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Sample records for biventricular assist device

  1. Biventricular assist using a portable driver in combination with implanted devices: preliminary experience.

    Science.gov (United States)

    von Segesser, L K; Tkebuchava, T; Leskosek, B; Marty, B; Pei, Y C; Turina, M

    1997-01-01

    Left ventricular assist systems with portable drive units are increasingly used in the clinical setting. However, such systems usually are not suitable for right ventricular support, and therefore, in the case of biventricular heart failure, they must be combined with other support devices that require additional drive consoles. As a result, most of the benefits of the wearable drive units (early mobilization and outpatient care) are lost. This present study was performed to evaluate biventricular support with implanted assist devices and a portable DC/battery-powered driver (Thoratec TLC-II). Electronic control by nonvolatile RAM accessible via RS232 interface, internal backup emergency battery, and optional manual activation are additional features of this 6 kg biventricular drive unit. In 3 bovine experiments (body weight 70 +/- 5 kg) partial cardiopulmonary bypass (CPB) was established, and two ventricular assist devices were implanted into a preperitoneal pocket on each side after connection to the right atrium and the pulmonary artery and to the left atrium and aorta, respectively. After weaning the patient from CPB, activated coagulation time (ACT) was kept at greater than 180 s, and biventricular support with the portable driver was activated. After 10 min, mean device flow stabilized at 3.5 +/- 0 L/min and remained at that level throughout the ensuing 6 h (3.5 +/- 0.3 L/min; NS). The heart rate moved from 130 +/- 13 beats per minute (bpm) at the end of CPB to 116 +/- 13 bpm after 10 min of assist (p < 0.05). Right atrial pressure moved from 11 +/- 2 mm Hg at the end of CPB to 13 +/- 3 mm Hg after 10 min of assist (not significant [NS]). Mean pulmonary artery pressure was 18 +/- mm Hg at the end of CPB and 17 +/- 5 mm Hg after 10 min of assist (NS). Left atrial pressure was 10 +/- 1 mm Hg at the end of CPB and 13 +/- 3 mm Hg after 10 min of assist (NS). Mean aortic pressure was 73 +/- 11 mm Hg at the end of CPB and 77 +/- 3 mm Hg after 10 min of assist (NS

  2. [First experience of application of assist circulation device using biventricular type "excor"].

    Science.gov (United States)

    Gordeev, M L; Karpenko, M A; Nikolaev, G V; Gnevashev, A S; Malaia, E Ia; Naĭmushin, A V; Rubinchik, V E; Sukhova, I V; Mitrofanova, L B; Somin, M Iu; Sazonova, Iu V; Stepanov, S S; Fedotov, P A

    2013-01-01

    The frequency of use of assist blood device as the "bridge" to the heart transplantation increased in last years. An assessment of results of first 7 implantations of assist circulation device using biventricular type "Excor" was made. The implantations were performed in Federal Almazov centre of the heart, blood and endocrinology. An observation period after implantation was since 11 till 301 days. The heart transplantation of 4 patients was carried out in different terms after implantation. One of the patients passed away on the fifth day due to the pulmonary embolism. Another patient died on the eleventh day after the implantation because of multiple organ failure against the background of severe chronic cardiac failure. The waiting list of heart transplantation includes 2 patients.

  3. Left Ventricular Assist Device Insertion in a Patient With Biventricular Noncompaction Cardiomyopathy, Ebstein Anomaly, and a Left Atrial Mass: A Case Report.

    Science.gov (United States)

    Kumar, Nikhil; Troianos, Christopher A; Baisden, Joshua S

    2016-12-15

    In this report, we present the case of a patient with biventricular noncompaction cardiomyopathy, Ebstein anomaly, and a left atrial mass who required emergent placement of a left ventricular assist device. The noncompaction cardiomyopathy complicated the left ventricular assist device implantation procedure because the thickened, trabeculated myocardium made it difficult to place the inflow cannula. We discuss our perioperative management strategy, in which transesophageal echocardiography was used, to help the surgical team identify the proper cannula placement and provide a bridge to transplantation.

  4. High pulmonary vascular resistance in addition to low right ventricular stroke work index effectively predicts biventricular assist device requirement.

    Science.gov (United States)

    Imamura, Teruhiko; Kinugawa, Koichiro; Kinoshita, Osamu; Nawata, Kan; Ono, Minoru

    2016-03-01

    Although the right ventricular stroke work index (RVSWI) is a good index for RV function, a low RVSWI is not necessarily an indicator for the need for a right ventricular assist device at the time of left VAD implantation. We here aimed to determine a more precise indicator for the need for a biventricular assist device (BiVAD). In total, 116 patients (mean age, 38 ± 14 years), who underwent hemodynamic assessments preoperatively including 12 BiVAD patients, and had been followed at our institute from 2003 to 2015, were included. Multivariate logistic regression analysis indicated that RVSWI and pulmonary vascular resistance (PVR) were independent predictors of BiVAD requirement (P 5 g/m, PVR 5, PVR > 3.7), (3) RV failure (RVSWI 3.7), and examined. Most of the patients in Group 4 (75 %), with acutely depressed hemodynamics and inflammatory responses in the myocardium, required BiVAD. Overall, patients with BiVAD had a worse survival rate as compared with those with LVAD alone. In conclusion, high PVR in addition to low RVSWI effectively predicts BiVAD requirement.

  5. Physiological control of dual rotary pumps as a biventricular assist device using a master/slave approach.

    Science.gov (United States)

    Stevens, Michael C; Wilson, Stephen; Bradley, Andrew; Fraser, John; Timms, Daniel

    2014-09-01

    Dual rotary left ventricular assist devices (LVADs) can provide biventricular mechanical support during heart failure. Coordination of left and right pump speeds is critical not only to avoid ventricular suction and to match cardiac output with demand, but also to ensure balanced systemic and pulmonary circulatory volumes. Physiological control systems for dual LVADs must meet these objectives across a variety of clinical scenarios by automatically adjusting left and right pump speeds to avoid catastrophic physiological consequences. In this study we evaluate a novel master/slave physiological control system for dual LVADs. The master controller is a Starling-like controller, which sets flow rate as a function of end-diastolic ventricular pressure (EDP). The slave controller then maintains a linear relationship between right and left EDPs. Both left/right and right/left master/slave combinations were evaluated by subjecting them to four clinical scenarios (rest, postural change, Valsalva maneuver, and exercise) simulated in a mock circulation loop. The controller's performance was compared to constant-rotational-speed control and two other dual LVAD control systems: dual constant inlet pressure and dual Frank-Starling control. The results showed that the master/slave physiological control system produced fewer suction events than constant-speed control (6 vs. 62 over a 7-min period). Left/right master/slave control had lower risk of pulmonary congestion than the other control systems, as indicated by lower maximum EDPs (15.1 vs. 25.2-28.4 mm Hg). During exercise, master/slave control increased total flow from 5.2 to 10.1 L/min, primarily due to an increase of left and right pump speed. Use of the left pump as the master resulted in fewer suction events and lower EDPs than when the right pump was master. Based on these results, master/slave control using the left pump as the master automatically adjusts pump speed to avoid suction and increases pump flow

  6. Long-term biventricular HeartWare ventricular assist device support--Case series of right atrial and right ventricular implantation outcomes.

    Science.gov (United States)

    Shehab, Sajad; Macdonald, Peter S; Keogh, Anne M; Kotlyar, Eugene; Jabbour, Andrew; Robson, Desiree; Newton, Phillip J; Rao, Sriram; Wang, Louis; Allida, Sabine; Connellan, Mark; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul C; Hayward, Christopher S

    2016-04-01

    There is limited information on outcomes using the HeartWare ventricular assist device (HVAD; HeartWare, Framington, MA) as a biventricular assist device, especially with respect to site of right ventricular assist device (RVAD) implantation. Outcomes in 13 patients with dilated cardiomyopathy and severe biventricular failure who underwent dual HVAD implantation as bridge to transplantation between August 2011 and October 2014 were reviewed. Of 13 patients, 10 were Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Level 1, and 3 were INTERMACS Level 2. Mean age was 45 ± 11 years, and mean body mass index was 26 ± 4 kg/m(2). There were 7 patients on temporary mechanical support pre-operatively (extracorporeal life support, n = 5; intra-aortic balloon pump, n = 2). The median hospital length of stay was 53 days (interquartile range [IQR] 33-70 days) with a median intensive care unit length of stay of 14 days (IQR 8-36 days). The median length of support on device was 269 days (IQR 93-426 days). The right HVAD was implanted in the right ventricular (RV) free wall in 6 patients and in the right atrial (RA) free wall in 7 patients. Transplantation was successfully performed in 5 patients, and overall survival for the entire cohort was 54%. RVAD pump thrombosis occurred in 3 of 6 RV pumps and 1 of 7 RA pumps. No left ventricular assist device pump thrombosis was observed. Bleeding tended to be higher in the RV implantation group (3 of 6 vs 0 of 7). During follow up, 6 patients died (4 of 7 in the RA group vs 2 of 6 in the RV group). Cause of death was multiple-organ failure in 3 patients, sepsis in 2 patients, and intracerebral hemorrhage in 1 patient. Critically ill patients who require biventricular support can be successfully bridged to transplant using 2 HVADs. RA implantation may allow right heart support with lower pump thrombosis and bleeding complications, although this was at the expense of a higher mortality in this cohort. Crown

  7. Left ventricular vs. biventricular mechanical support: Decision making and strategies for avoidance of right heart failure after left ventricular assist device implantation.

    Science.gov (United States)

    Dandel, Michael; Krabatsch, Thomas; Falk, Volkmar

    2015-11-01

    Left ventricular assist devices (LVADs) are safer and provide better survival and better quality of life than biventricular assist devices (BVADs) but end-stage heart failure often involves both ventricles, even if its initial cause was left-sided heart disease. Right ventricular failure (RVF) is also a severe complication in about 25% of patients receiving an LVAD, with high perioperative morbidity (renal, hepatic or multi-organ failure) and mortality. Patients who receive an RV assist device (RVAD) only days after LVAD insertion fare much worse than those who receive an RVAD simultaneously with LVAD implantation. Temporary RVAD support in LVAD recipients with high risk for postoperative RVF can avoid permanent BVAD support. Thus, patients who definitely need a BVAD should already be identified preoperatively or at least intra-operatively. However, although the initial biochemical, hemodynamic and echocardiographic patient profiles at admission may suggest the need for a BVAD, many risk factors may be favorably modified by various strategies that may result in avoidance of RVF after LVAD implantation. This article summarizes the knowledge of risk factors for irreversible RVF after LVAD implantation and strategies to optimize RV function (preoperatively, intra-operatively and post-operatively) aimed to reduce the number of BVAD implantations. Special attention is focused on assessment of RV size, geometry and function in relation to loading conditions with the goal of predicting preoperatively the RV changes which might be induced by RV afterload reduction with the LVAD. The review also provides a theoretical and practical basis for clinicians intending to be engaged in this field. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Biventricular heart assistance: preliminary tests on the hybrid (hydro-numerical) circulatory model.

    OpenAIRE

    Kozarski, Maciej; Ferrari, Gianfranco; Zielinski, Krzysztof; Gorczynska, Krystyna; Palko, Krzysztof Jakub; Darowski, Marek

    2010-01-01

    Objectives: The aim of the study is to show how hybrid (hydro-numerical) circulatory model is effectively used to reproduce different clinical physiological as well as pathological cases when parallel biventricular (LVAD and RVAD) heart assistance is applied. That opens unique R&D and educational opportunities to investigate and demonstrate influence of assistance procedures on hemodynamic and energetic parameters of the circulation e.g. to show situations when different timing or pressure ar...

  9. Anastomose cavo-pulmonar associada ao suporte circulatório esquerdo comparada à assistência biventricular na falência cardíaca aguda Cavo-pulmonary anastomosis associated with left ventricular in comparison with biventricular circulatory support in acute heart failure

    Directory of Open Access Journals (Sweden)

    Luis Alberto Saraiva Santos

    2012-12-01

    Full Text Available OBJETIVO: Este estudo avaliou o desempenho hemodinâmico e as alterações miocárdicas decorrentes do emprego de dispositivos de assistência ventricular esquerda (DAVE, associado ou não à descompressão do ventrículo direito por meio de derivação cavo-pulmonar, sendo esses achados comparados ao emprego de assistência circulatória biventricular. MÉTODOS: Vinte e um suínos foram submetidos à indução de insuficiência cardíaca através de fibrilação ventricular, sendo a atividade circulatória mantida por DAVE durante 180 minutos. No grupo controle, foi apenas implantado o DAVE. No grupo derivação, além do DAVE foi realizada cirurgia de derivação cavo-pulmonar. No grupo biventricular, foi instituída assistência biventricular. Foram monitoradas as pressões intracavitárias por 3 horas de assistência e amostras do endocárdio dos dois ventrículos foram coletadas e analisadas à microscopia óptica e eletrônica. RESULTADOS: O lactato sérico foi significativamente menor no grupo biventricular (P=0,014. A diferença observada entre o fluxo do DAVE nos grupos derivação e controle (+55±14 ml/kg/min, P=0,072 não foi significativa, enquanto que o fluxo no grupo biventricular foi significativamente maior (+93±17 ml/kg/min, P=0,012 e se manteve estável durante o experimento. A pressão arterial média (PAM se manteve constante apenas no grupo biventricular (POBJECTIVE: Right ventricular (RV failure during left ventricular assist device (LVAD support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavo-pulmonary anastomosis on LVAD performance and RV myocardial compromise in comparison with biventricular circulatory support, in a model of biventricular failure. METHODS: LVAD support was performed by centrifugal pump in 21 pigs with severe biventricular failure obtained by FV induction. Animals were randomized to be submitted to cavo-pulmonary anastomosis, to

  10. Optimal pacing for right ventricular and biventricular devices: minimizing, maximizing, and right ventricular/left ventricular site considerations.

    Science.gov (United States)

    Gillis, Anne M

    2014-10-01

    The results from numerous clinical studies provide guidance for optimizing outcomes related to RV or biventricular pacing in the pacemaker and ICD populations. (1) Programming algorithms to minimize RV pacing is imperative in patients with dual-chamber pacemakers who have intrinsic AV conduction or intermittent AV conduction block. (2) Dual-chamber ICDs should be avoided in candidates without an indication for bradycardia pacing. (3) Alternate RV septal pacing sites may be considered at the time of pacemaker implantation. (4) Biventricular pacing may be beneficial in some patients with mild LV dysfunction. (5) LV lead placement at the site of latest LV activation is desirable. (6) Programming CRT systems to achieve biventricular/LV pacing >98.5% is important. (7) Protocols for AV and VV optimization in patients with CRT are not recommended after device implantation but may be considered for CRT nonresponders. (8) Novel algorithms to maximize the benefit of CRT are in evolution further.

  11. Recovery of right heart function with temporary right ventricular assist using a centrifugal pump in patients with severe biventricular failure.

    Science.gov (United States)

    Saito, Shunsuke; Sakaguchi, Taichi; Miyagawa, Shigeru; Nishi, Hiroyuki; Yoshikawa, Yasushi; Fukushima, Satsuki; Daimon, Takashi; Sawa, Yoshiki

    2012-08-01

    Long-term outcomes of a biventricular assist device (BiVAD) support are worse than those of an isolated left ventricular assist device (LVAD) support. This study evaluated our strategy for right heart failure using a temporary right VAD (RVAD) with an extracorporeal centrifugal pump. From January 2001 to December 2010, 108 patients underwent LVAD implantation at our institution and their clinical outcomes were studied. A temporary centrifugal RVAD was implanted in 26 patients. Multivariate logistic regression revealed pre-operative extracorporeal life support (odds ratio [OR], 37.0), central venous pressure (OR, 1.2), mean pulmonary artery pressure (OR, 0.9), and serum total bilirubin (OR, 1.4) were the risk factors for RVAD requirement. RVAD-off test was conducted, and 11 of the 26 patients showed significant recovery of right heart function and were eventually removed from RVAD support. The survival of patients with isolated LVAD was significantly better than those with a paracorporeal pulsatile BiVAD (80% vs 11% at 1 year, p < 0.001). However, there was no significant difference between the survival of patients who underwent isolated LVAD support and those who were initially implanted with temporary BiVAD but underwent the RVAD removal (80% vs 73% at 1 year, p = 0.827). Our strategy with temporary RVAD for severe acute right heart failure was effective in selecting the patients who could be weaned from RVAD support. Patient survival was improved by avoiding the long-term support with a paracorporeal pulsatile BiVAD. Copyright © 2012 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  12. Ventricular assist device in univentricular heart physiology.

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    Brancaccio, Gianluca; Gandolfo, Fabrizio; Carotti, Adriano; Amodeo, Antonio

    2013-04-01

    The use of mechanical cardiac assistance is well established as a bridge to orthotopic heart transplantation (OHT) or to recovery for patients with congestive heart failure, however, the experience in single ventricle (SV) physiology is still limited. We report two cases of mechanical assistance in patients with SV physiology: a 2-year old male with hypoplastic left heart syndrome who underwent Norwood Stage I and II followed by HF and a 4-year old female with a univentricular heart who developed a severe right ventricular dysfunction 2 years after a cavopulmonary shunt. Mechanical support utilizing ventricular assist devices (VADs) is considered a valid tool to bridge patients with congestive heart failure to either OHT or to recovery. Increasing experience and improved outcomes utilizing this technology in children with biventricular hearts have led to considering employing these devices in failing SV treatment. We present 2 cases of terminally ill children with SV who were assisted with a VAD.

  13. Left Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    Khuansiri Narajeenron

    2017-04-01

    Full Text Available Audience: The audience for this classic team-based learning (cTBL session is emergency medicine residents, faculty, and students; although this topic is applicable to internal medicine and family medicine residents. Introduction: A left ventricular assist device (LVAD is a mechanical circulatory support device that can be placed in critically-ill patients who have poor left ventricular function. After LVAD implantation, patients have improved quality of life.1 The number of LVAD patients worldwide continues to rise. Left-ventricular assist device patients may present to the emergency department (ED with severe, life-threatening conditions. It is essential that emergency physicians have a good understanding of LVADs and their complications. Objectives: Upon completion of this cTBL module, the learner will be able to: 1 Properly assess LVAD patients’ circulatory status; 2 appropriately resuscitate LVAD patients; 3 identify common LVAD complications; 4 evaluate and appropriately manage patients with LVAD malfunctions. Method: The method for this didactic session is cTBL.

  14. Biventricular Mechanical Circulatory Support Does Not Prevent Delayed Myocardial Ventricular Rupture following Myocardial Infarction

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    Yazhini Ravi

    2013-01-01

    Full Text Available Cardiogenic shock and myocardial rupture can complicate an acute myocardial infarction (AMI. A case is reported in which a 58-year-old male with an acute inferior myocardial infarction required placement of biventricular assist device for hemodynamic support eight days after the onset of his AMI; eleven days after his AMI, the patient developed abrupt onset of hemodynamic instability with massive bleeding from his chest tube due to delayed free wall myocardial rupture that was discovered when he was taking emergently to the operating room. Myocardial rupture in patients with a ventricular assist device should be considered in the differential diagnosis in the event of acute hemodynamic compromise. A high level of suspicion for such a complication should prompt aggressive and emergent actions including surgery. We present a case of delayed free wall myocardial rupture following an acute inferior wall myocardial infarction in a patient with biventricular mechanical circulatory support.

  15. Electrohydraulic ventricular assist device development.

    Science.gov (United States)

    Diegel, P D; Mussivand, T; Holfert, J W; Nahon, D; Miller, J; Maclean, G K; Santerre, J P; Bearnson, G B; Juretich, J; Hansen, A C

    1991-01-01

    A 64 ml (effective stroke volume) in vitro electrohydraulic ventricular assist device (VAD) prototype has been built. The energy converter is an axial flow pump driven by a brushless direct current (DC) motor. Systole begins as silicone oil is pumped from the volume displacement chamber (VDC) into the ventricle, displacing the flexing diaphragm separating the oil and the blood. In diastole, the motor reverses, providing active filling by pumping oil from the ventricle into the VDC. The surface mount electronic internal controller provides motor commutator, energy management, telemetry, and physiologic control functions. Energy is supplied externally by either a 12 V DC power supply or a 12 V DC rechargeable battery and is transmitted through the skin by a transcutaneous energy transformer (TET). Energy can also be supplied by a 12 V DC rechargeable internal battery. Bidirectional infrared telemetry is used to transmit information between the internal and external controllers.

  16. 21 CFR 870.3545 - Ventricular bypass (assist) device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ventricular bypass (assist) device. 870.3545... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3545 Ventricular bypass (assist) device. (a) Identification. A ventricular bypass (assist) device is a device that assists...

  17. Assistive Devices for Students with Disabilities.

    Science.gov (United States)

    Wisniewski, Lech; Sedlak, Robert

    1992-01-01

    Describes a variety of devices that can assist students with disabilities. Highlights recently developed devices for students with specific learning disabilities, and with vision, hearing, health, physical, and speech and language impairments. The devices can help rehabilitate, reeducate, facilitate normalcy, or augment current functioning. (GLR)

  18. Cardiogenic shock associated with loco-regional anesthesia rescued with left ventricular assist device implantation

    Directory of Open Access Journals (Sweden)

    Droogan Christopher

    2010-12-01

    Full Text Available Abstract A healthy 53 year old man developed profound cardiogenic shock following instillation of bupivacaine-lidocaine-epinephrine solution as a locoregional anesthetic for elective outpatient shoulder surgery. Intubation, resuscitation, and transfer to the nearby hospital were done: echocardiography showed profound biventricular dysfunction; cardiac catheterization showed normal coronary arteries. Despite placement of an intra-aortic balloon pump and intravenous vasoactive drugs, the patient remained in shock. Stabilization was achieved with emergent institution of cardiopulmonary bypass and placement of a temporary left ventricular assist device (LVAD. Twenty-four hours later, cardiac function normalized and the LVAD was removed. The patient was discharged five days later and remained with normal heart function in three-year follow-up.

  19. Left Ventricular Assist Device Implantation After Intracardiac Parachute Device Removal.

    Science.gov (United States)

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Bruckner, Brian A; Suarez, Erik E; Estep, Jerry D; Loebe, Matthias

    2015-08-01

    Left ventricular assist device implantation is a proven and efficient modality for the treatment of end-stage heart failure. Left ventricular assist device versatility as a bridge to heart transplantation or destination therapy has led to improved patient outcomes with a concomitant rise in its overall use. Other less invasive treatment modalities are being developed to improve heart function and morbidity and mortality for the heart failure population. Percutaneous ventricular restoration is a new investigational therapy that deploys an intracardiac parachute to wall off damaged myocardium in patients with dilated left ventricles and ischemic heart failure. Clinical trials are under way to test the efficacy of percutaneous ventricular restoration using the parachute device. This review describes our encounter with the parachute device, its explantation due to refractory heart failure, and surgical replacement with a left ventricular assist device. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Use of the Nippon-Zeon pneumatic ventricular assist device as a bridge to cardiac transplantation.

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    Deleuze, P H; Le Besnerais, P; Mazzucotellu, J P; Abe, Y; Miyama, M; Mourtada, A; Benvenuti, C; Loisance, D Y

    1994-01-01

    The Nippon-Zeon (NZ) ventricular assist device is a sac type, air driven, heterotopic, external pump. Its performance has been evaluated in Japan as a bridge to myocardial recovery. Few data are available on the device as a bridge to heart transplantation. Since 1991, 10 patients (9 men) were bridged to heart transplantation with NZ, all in biventricular support. The mean age was 39 +/- 13 years (range, 21-60 years), mean body weight was 75 +/- 13 kg (range, 51-95 kg). Five patients had a dilated cardiopathy, and five were ischemic (three acute myocardial infarctions). Despite maximal inotropic support, including enoximone in seven, epinephrine in three, and intraaortic balloon pumping in one, eight patients were anuric, three were in acute hepatic failure, and three were intubated. Preoperative hemodynamic and biologic values were: cardiac index, 1.57 +/- 0.4 l/min/m2; pulmonary capillary wedge pressure, 34 +/- 5 mmHg; creatinine, 200 +/- 80 mumol/l; blood urea nitrogen, 17.5 +/- 8 mmol/l; total bilirubin 36 +/- 6 mumol/l; aspartate aminotransferase, 1,000 +/- 2,000 IU/l. In all patients, a biventricular assist device was implanted without the use of cardiopulmonary bypass. Improvement occurred immediately in all but one. Mean left ventricular flow was 4.5 +/- 0.8 l/min. Anticoagulation was maintained with intravenous heparin. Recently for bleeding was required in one case (10%), and two patients had positive blood cultures that were successfully treated. There was no mechanical failure. Hemolysis was not significant (lactate dehydrogenase, 378 +/- 50 IU/l; plasma-free hemoglobin below 10 mg/dl). Each device was free of thrombi and deposits at time of explantation. One patient died while on assist. Nine patients (90%) were transplanted after 11 +/- 8 days (range, 1-32 days). Three died early after transplantation, one of graft failure, two of sepsis. Six patients (66%) could be discharged. The follow-up ranges from 7 to 28 months. NZ is a simple, reliable

  1. Ventricular assist device support as a bridge to heart transplantation in patients with giant cell myocarditis.

    Science.gov (United States)

    Murray, Lindsay K; González-Costello, Jose; Jonas, Samual N; Sims, Daniel B; Morrison, Kerry A; Colombo, Paolo C; Mancini, Donna M; Restaino, Susan W; Joye, Evan; Horn, Evelyn; Takayama, Hiroo; Marboe, Charles C; Naka, Yoshifumi; Jorde, Ulrich P; Uriel, Nir

    2012-03-01

    Giant cell myocarditis (GCM) carries a poor prognosis and many patients require end-stage therapies. This study sought to determine the outcome of patients bridged with ventricular assist devices (VAD) to orthotopic heart transplantation (OHT). A retrospective data collection of all patients with GCM was performed. Diagnosis was determined by endomyocardial or explanted heart biopsy. Eight patients were found, but two of those patients went directly to OHT and were excluded. The remaining six patients received VADs, and these patients, aged 44 ± 18 years, were included. Five of the six patients were bridged with biventricular support and one patient was supported by left ventricular assist device (LVAD) alone. Two patients died on device support. Four patients were bridged to OHT 77 ± 42 days after device implantation. All four patients bridged with a VAD are alive, with a mean follow-up of 5.7 ± 4.1 years. Two patients were found to have recurrent GCM in the transplanted heart and were treated successfully with immunosuppression. Three patients had high grade (2R) rejection at 66 ± 52 days post-OHT. Cardiac function was preserved in all patients, and only one patient had cardiac allograft vasculopathy. Patients with end-stage GCM can be successfully bridged with VADs to OHT with very good post-OHT survival. The proper immunosuppressive regimen for this group needs further investigation given the frequency of rejection and GCM recurrence.

  2. Unlocking the box: basic requirements for an ideal ventricular assist device controller.

    Science.gov (United States)

    Medvedev, Alexander L; Karimov, Jamshid H; Kuban, Barry D; Horvath, David J; Moazami, Nader; Fukamachi, Kiyotaka

    2017-05-01

    A modern ventricular assist device (VAD) system comprises an implantable rotary blood pump and external components located outside the patient's body: a wearable controller connected to the pump via a percutaneous cable, wearable rechargeable batteries, battery charger, alternating- and direct-current power supplies, and a hospital device to control and monitor the system. If the blood pump is the 'heart' of a VAD system, the controller is its 'brain.' The controller drives the pump's electrical motor; varies the pump speed or flow based on user commands or feedback signals; collects, processes, and stores data; performs self-diagnostics; transmits to and receives data from other system components, i.e., hospital monitor and batteries; and provides various types of user interface - audible, visual, and tactile. Areas covered: Here we describe the essential functions and basic design of the VAD external controller and give our views on the future of this technology. Expert commentary: Controllers for VAD systems are crucial to their successful operation. The current clinically available system comprises an external power supply and patient-friendly controller unit. Future controller solutions may enable remote hospital monitoring, more intuitive system interface, and the potential to use a single controller to automatically control a biventricular assist device configuration.

  3. The Achilles' heel of left ventricular assist device therapy: right ventricle.

    Science.gov (United States)

    Ranganath, Neel K; Smith, Deane E; Moazami, Nader

    2018-04-07

    Many patients suffer from either persistent right ventricular failure (RVF) at the time of left ventricular assist device (LVAD) or have ongoing symptoms consistent with RVF during chronic mechanical circulatory support. The lack of long-term right ventricular assist devices (RVADs) has limited the impact that mechanical circulatory support can provide to patients with biventricular failure. We aim to review the entire spectrum of RVF in patients receiving LVADs and reflect on why this entity remains the Achilles' heel of LVAD therapy. In the early postoperative period, LVAD implantation reduces right ventricle (RV) afterload, but RV dysfunction may be exacerbated secondary to increased venous return. With prolonged therapy, the decreased RV afterload leads to improved RV contractile function. Bayesian statistical models outperform previously published preoperative risk scores by considering inter-relationships and conditional probabilities amongst independent variables. Various echocardiographic parameters and the pulmonary artery pulsatility index have shown promise in predicting post-LVAD RVF. Recent publications have delineated the emergence of 'delayed' RVF. Several devices are currently being investigated for use as RVADs. Post-LVAD RVF depends on the RV's ability to adapt to acute hemodynamic changes imposed by the LVAD. Management options are limited due to the lack of an easily implantable, chronic-use RVAD.

  4. Long-term total cardiac support in a Fontan-type circulation with HeartMate II left ventricular assist device.

    Science.gov (United States)

    Tchantchaleishvili, Vakhtang; Hallinan, William; Schwarz, Karl Q; Massey, Howard Todd

    2016-05-01

    Interest in utilizing long-term mechanical circulatory support for Fontan-type circulation has been high. Unfortunately, so far such attempts have not been successful. Herein, we are presenting the first case of an individual with biventricular heart failure and Fontan-type circulation on long-term mechanical circulatory support with a continuous-flow left ventricular assist device. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  5. Evaluating Personal Assistants on Mobile devices

    OpenAIRE

    Kiseleva, Julia; de Rijke, Maarten

    2017-01-01

    The iPhone was introduced only a decade ago in 2007 but has fundamentally changed the way we interact with online information. Mobile devices differ radically from classic command-based and point-and-click user interfaces, now allowing for gesture-based interaction using fine-grained touch and swipe signals. Due to the rapid growth in the use of voice-controlled intelligent personal assistants on mobile devices, such as Microsoft's Cortana, Google Now, and Apple's Siri, mobile devices have be...

  6. Experience With a Long-term Pulsatile Ventricular Assist Device as a Bridge to Heart Transplant in Adults.

    Science.gov (United States)

    Gómez Bueno, Manuel; Segovia Cubero, Javier; Serrano Fiz, Santiago; Ugarte Basterrechea, Juan; Hernández Pérez, Francisco José; Goirigolzarri Artaza, Josebe; Castedo Mejuto, Evaristo; Burgos Lázaro, Raúl; García Montero, Carlos; Moñivas Palomero, Vanessa; Mingo Santos, Susana; González Román, Ana Isabel; Álvarez Avelló, José Manuel; Vidal Fernández, Mercedes; Forteza Gil, Alberto; Alonso-Pulpón, Luis

    2017-09-01

    Most long-term ventricular assist devices (VADs) that are currently implanted are intracorporeal continuous-flow devices. Their main limitations include their high cost and inability to provide biventricular support. The aim of this study was to describe the results of using paracorporeal pulsatile-flow VADs as a bridge to transplant (BTT) in adult patients. Retrospective analysis of the characteristics, complications, and outcomes of a single-center case series of consecutive patients treated with the EXCOR VAD as BTT between 2009 and 2015. During the study period, 25 VADs were implanted, 6 of them biventricular. Ventricular assist devices were indicated directly as a BTT in 12 patients and as a bridge to decision in 13 due to the presence of potentially reversible contraindications or chance of heart function recovery. Twenty patients (80%) were successfully bridged to heart transplant after a median of 112 days (range, 8-239). The main complications included infectious (52% of patients), neurological events (32%, half of them fatal), bleeding (28%), and VAD malfunction requiring component replacement (28%). Eighty percent of patients with the EXCOR VAD as BTT achieved the goal after an average of almost 4 months of support. The most frequent complications were infectious, and the most severe were neurological. In our enivonment, the use of these pulsatile-flow VAD as BTT is a feasible strategy that obtains similar outcomes to those of intracorporeal continuous-flow devices. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  7. Preoperative three-dimensional echocardiography to assess risk of right ventricular failure after left ventricular assist device surgery.

    Science.gov (United States)

    Kiernan, Michael S; French, Amy L; DeNofrio, David; Parmar, Yuvrajsinh J; Pham, Duc Thinh; Kapur, Navin K; Pandian, Natesa G; Patel, Ayan R

    2015-03-01

    Right ventricular failure (RVF) is associated with significant morbidity after left ventricular assist device (LVAD) surgery. Hemodynamic, clinical, and 2-dimensional echocardiographic variables poorly discriminate patients at risk of RVF. We examined the utility of 3-dimensional echocardiography (3DE) right ventricular (RV) volumetric assessment to identify patients at risk for RVF. RVF was defined as the need for inotropic infusion for >14 days after LVAD surgery or the need for biventricular assist device support. Preoperative RV volumes and ejection fraction (EF) were measured, blinded to clinical data, from transthoracic 3DE full volume data sets in 26 patients. Baseline variables and 3DE RV indices were compared between patients with and without RVF. Twenty-four patients received continuous-flow LVADs, and 2 required biventricular support devices. Ten patients required prolonged inotropes after LVAD placement. Baseline characteristics associated with RVF included higher right atrial pressure, higher right atrial pressure to pulmonary capillary wedge pressure ratio, and lower cardiac index and RV stroke work index (RVSWI). Echocardiographic indices associated with RVF included 3DE indexed RV end-diastolic and end-systolic volumes (RVEDVI and RVESVI) and RV ejection fraction (RVEF). The relationship between 3DE quantification of RV volumes and the development of RVF was independent from RVSWI: RVEDVI: odds ratio (OR) 1.16, 95% confidence interval (CI) 1.00-1.33 (P = .04); RVESVI: OR 1.14, 95% CI 1.01-1.28 (P = .03). Quantitative 3DE is a promising method for pre-LVAD RV assessment. RV volumes assessed by 3DE are predictive of RVF in LVAD recipients independently from hemodynamic correlates of RV function. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Mycobacterium chimaera left ventricular assist device infections.

    Science.gov (United States)

    Balsam, Leora B; Louie, Eddie; Hill, Fred; Levine, Jamie; Phillips, Michael S

    2017-06-01

    A global outbreak of invasive Mycobacterium chimaera infections after cardiac surgery has recently been linked to bioaerosols from contaminated heater-cooler units. The majority of cases have occurred after valvular surgery or aortic graft surgery and nearly half have resulted in death. To date, infections in patients with left ventricular assist devices (LVADs) have not been characterized in the literature. We report two cases of device-associated M. chimaera infection in patients with continuous-flow LVADs and describe challenges related to diagnosis and management in this population. © 2017 Wiley Periodicals, Inc.

  9. Chronic ventricular assist device support: surgical innovation.

    Science.gov (United States)

    Rojas, Sebastian V; Hanke, Jasmin S; Haverich, Axel; Schmitto, Jan D

    2016-05-01

    Ventricular assist device (VAD) therapy is currently one of the fastest-developing fields in cardiac surgery. Consistently improved technology, research, and gain of clinical experience have established VADs as an important option for the treatment of congestive heart failure. During the past year, novel devices and less invasive surgical procedures have been revolutionizing this field. The purpose of this manuscript is to review these innovations with special emphasis on device-related surgery. Device miniaturization has enabled less invasive VAD surgery, excluding the need for full sternotomy. Recent data show that intrahospital survival rates following less invasive VAD implantation are surpassing 90%. Secondly, two new devices, Heartmate 3 and MVAD, are being applied and tested for clinical application. In this context, the Heartmate 3 CE mark study recently concluded with excellent outcomes and without any pump thrombosis or device malfunctions. The first clinical results of the newest generation of VADs are very promising compared with old-generation devices. Furthermore, less invasive surgery is becoming a standard for the implantation, exchange, or explantation of left VADs. The joint venture of improved technology and innovative surgical techniques will push this field forward to even better outcomes and reduced complication rates.

  10. Beyond the hearing aid: Assistive listening devices

    Science.gov (United States)

    Holmes, Alice E.

    2003-04-01

    Persons with hearing loss can obtain great benefit from hearing aids but there are many situations that traditional amplification devices will not provide enough help to ensure optimal communication. Assistive listening and signaling devices are designed to improve the communication of the hearing impaired in instances where traditional hearing aids are not sufficient. These devices are designed to help with problems created by listening in noise or against a competing message, improve distance listening, facilitate group conversation (help with problems created by rapidly changing speakers), and allow independence from friends and family. With the passage of the Americans with Disabilities Act in 1990, assistive listening devices (ALDs) are becoming more accessible to the public with hearing loss. Employers and public facilities must provide auxiliary aids and services when necessary to ensure effective communication for persons who are deaf or hard of hearing. However many professionals and persons with hearing loss are unaware of the various types and availability of ALDs. An overview of ALDs along with a discussion of their advantages and disadvantages will be given.

  11. Brain-controlled body movement assistance devices and methods

    Science.gov (United States)

    Leuthardt, Eric C.; Love, Lonnie J.; Coker, Rob; Moran, Daniel W.

    2017-01-10

    Methods, devices, systems, and apparatus, including computer programs encoded on a computer storage medium, for brain-controlled body movement assistance devices. In one aspect, a device includes a brain-controlled body movement assistance device with a brain-computer interface (BCI) component adapted to be mounted to a user, a body movement assistance component operably connected to the BCI component and adapted to be worn by the user, and a feedback mechanism provided in connection with at least one of the BCI component and the body movement assistance component, the feedback mechanism being configured to output information relating to a usage session of the brain-controlled body movement assistance device.

  12. The medical physics of ventricular assist devices

    International Nuclear Information System (INIS)

    Wood, Houston G; Throckmorton, Amy L; Untaroiu, Alexandrina; Song Xinwei

    2005-01-01

    Millions of patients, from infants to adults, are diagnosed with congestive heart failure each year all over the world. A limited number of donor hearts available for these patients results in a tremendous demand for alternative, supplemental circulatory support in the form of artificial heart pumps or ventricular assist devices (VADs). The development procedure for such a device requires careful consideration of biophysical factors, such as biocompatibility, haemolysis, thrombosis, implantability, physiologic control feasibility and pump performance. Conventional pump design equations based on Newton's law and computational fluid dynamics (CFD) are readily used for the initial design of VADs. In particular, CFD can be employed to predict the pressure-flow performance, hydraulic efficiencies, flow profile through the pump, stress levels and biophysical factors, such as possible blood cell damage. These computational flow simulations may involve comprehensive steady and transient flow analyses. The transient simulations involve time-varying boundary conditions and virtual modelling of the impeller rotation in the blood pumps. After prototype manufacture, laser flow measurements with sophisticated optics and mock circulatory flow loop testing assist with validation of pump design and identification of irregular flow patterns for optimization. Additionally, acute and chronic animal implants illustrate the blood pump's ability to support life physiologically. These extensive design techniques, coupled with fundamental principles of physics, ensure a reliable and effective VAD for thousands of heart failure patients each year

  13. The medical physics of ventricular assist devices

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Houston G [Mechanical and Aerospace Engineering Department, Virginia Artificial Heart Institute, 122 Engineers Way, University of Virginia, Charlottesville, VA (United States); Throckmorton, Amy L [Biomedical Engineering Department, Virginia Artificial Heart Institute, University of Virginia, Charlottesville, VA (United States); Untaroiu, Alexandrina [Mechanical and Aerospace Engineering Department, Virginia Artificial Heart Institute, 122 Engineers Way, University of Virginia, Charlottesville, VA (United States); Song Xinwei [Mechanical and Aerospace Engineering Department, Virginia Artificial Heart Institute, 122 Engineers Way, University of Virginia, Charlottesville, VA (United States)

    2005-03-01

    Millions of patients, from infants to adults, are diagnosed with congestive heart failure each year all over the world. A limited number of donor hearts available for these patients results in a tremendous demand for alternative, supplemental circulatory support in the form of artificial heart pumps or ventricular assist devices (VADs). The development procedure for such a device requires careful consideration of biophysical factors, such as biocompatibility, haemolysis, thrombosis, implantability, physiologic control feasibility and pump performance. Conventional pump design equations based on Newton's law and computational fluid dynamics (CFD) are readily used for the initial design of VADs. In particular, CFD can be employed to predict the pressure-flow performance, hydraulic efficiencies, flow profile through the pump, stress levels and biophysical factors, such as possible blood cell damage. These computational flow simulations may involve comprehensive steady and transient flow analyses. The transient simulations involve time-varying boundary conditions and virtual modelling of the impeller rotation in the blood pumps. After prototype manufacture, laser flow measurements with sophisticated optics and mock circulatory flow loop testing assist with validation of pump design and identification of irregular flow patterns for optimization. Additionally, acute and chronic animal implants illustrate the blood pump's ability to support life physiologically. These extensive design techniques, coupled with fundamental principles of physics, ensure a reliable and effective VAD for thousands of heart failure patients each year.

  14. In Vivo Evaluation of Active and Passive Physiological Control Systems for Rotary Left and Right Ventricular Assist Devices.

    Science.gov (United States)

    Gregory, Shaun D; Stevens, Michael C; Pauls, Jo P; Schummy, Emma; Diab, Sara; Thomson, Bruce; Anderson, Ben; Tansley, Geoff; Salamonsen, Robert; Fraser, John F; Timms, Daniel

    2016-09-01

    Preventing ventricular suction and venous congestion through balancing flow rates and circulatory volumes with dual rotary ventricular assist devices (VADs) configured for biventricular support is clinically challenging due to their low preload and high afterload sensitivities relative to the natural heart. This study presents the in vivo evaluation of several physiological control systems, which aim to prevent ventricular suction and venous congestion. The control systems included a sensor-based, master/slave (MS) controller that altered left and right VAD speed based on pressure and flow; a sensor-less compliant inflow cannula (IC), which altered inlet resistance and, therefore, pump flow based on preload; a sensor-less compliant outflow cannula (OC) on the right VAD, which altered outlet resistance and thus pump flow based on afterload; and a combined controller, which incorporated the MS controller, compliant IC, and compliant OC. Each control system was evaluated in vivo under step increases in systemic (SVR ∼1400-2400 dyne/s/cm(5) ) and pulmonary (PVR ∼200-1000 dyne/s/cm(5) ) vascular resistances in four sheep supported by dual rotary VADs in a biventricular assist configuration. Constant speed support was also evaluated for comparison and resulted in suction events during all resistance increases and pulmonary congestion during SVR increases. The MS controller reduced suction events and prevented congestion through an initial sharp reduction in pump flow followed by a gradual return to baseline (5.0 L/min). The compliant IC prevented suction events; however, reduced pump flows and pulmonary congestion were noted during the SVR increase. The compliant OC maintained pump flow close to baseline (5.0 L/min) and prevented suction and congestion during PVR increases. The combined controller responded similarly to the MS controller to prevent suction and congestion events in all cases while providing a backup system in the event of single controller failure

  15. Dissatisfaction and nonuse of assistive devices among frail elders.

    Science.gov (United States)

    Mann, William C; Goodall, Sara; Justiss, Michael D; Tomita, Machiko

    2002-01-01

    This article is based on the Rehabilitation Engineering Research Center on Aging Consumer Assessments Study. The sample included 1,056 subjects who reported use or nonuse of assistive devices. Of these subjects, 873 identified reasons for not using or being dissatisfied with certain assistive devices. Study participants owned a mean of 14.2 assistive devices, used 84.8% of the devices they owned, and were satisfied with 84.2% of the devices they owned. Devices were grouped into categories based on the type of impairment they addressed (hearing, vision, cognitive, and musculoskeletal/neuromotor). Study participants owned the largest number of devices in the musculoskeletal/neuromotor category (mean of 10.6 devices). Devices in the hearing impairment category were rated lowest by participants in terms of satisfaction. Almost half of all reasons listed for not using certain assistive devices related to perceived lack of need.

  16. Association between frequency of atrial and ventricular ectopic beats and biventricular pacing percentage and outcomes in patients with cardiac resynchronization therapy

    DEFF Research Database (Denmark)

    Ruwald, Martin H; Mittal, Suneet; Ruwald, Anne-Christine

    2014-01-01

    -defibrillator device with data available on biventricular pacing percentage and pre-implantation 24-h Holter recordings were included. Using logistic regression, we estimated the influence of ectopic beats on the percentage of biventricular pacing. Reverse remodeling was measured as reductions in atrial and left...

  17. Evaluation of inflow cannulation site for implantation of right-sided rotary ventricular assist device.

    Science.gov (United States)

    Gregory, Shaun D; Pearcy, Mark J; Fraser, John; Timms, Daniel

    2013-08-01

    Right heart dysfunction is one of the most serious complications following implantation of a left ventricular assist device, often leading to the requirement for short- or long-term right ventricular assist device (RVAD) support. The inflow cannulation site induces major hemodynamic changes and so there is a need to optimize the site used depending on the patient's condition. Therefore, this study evaluated and compared the hemodynamic influence of right atrial cannulation (RAC) and right ventricular cannulation (RVC) inflow sites. An in vitro variable heart failure mock circulation loop was used to compare RAC and RVC in mild and severe biventricular heart failure (BHF) conditions. In the severe BHF condition, higher ventricular ejection fraction (RAC: 13.6%, RVC: 32.7%) and thus improved heart chamber and RVAD washout were observed with RVC, which suggested this strategy might be preferable for long-term support (i.e., bridge-to-transplant or destination therapy) to reduce the risk of thrombus formation. In the mild BHF condition, higher pulmonary valve flow (RAC: 3.33 L/min, RVC: 1.97 L/min) and lower right ventricular stroke work (RAC: 0.10 W, RVC: 0.13 W) and volumes were recorded with RAC. These results indicate an improved potential for myocardial recovery, thus RAC should be chosen in this condition. This in vitro study suggests that RVAD inflow cannulation site should be chosen on a patient-specific basis with a view to the support strategy to promote myocardial recovery or reduce the risk of long-term complications. © 2013, Copyright the Authors. Artificial Organs © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  18. Elastic path controller for assistive devices.

    Science.gov (United States)

    Long, B; Rebsamen, B; Burdet, E; Yu, H; Teo, C L

    2005-01-01

    Robotic assistive devices that constrain motion along pre-defined paths are useful in reducing maneuvering efforts by human. This paper introduces an Elastic Path Controller (EPC) that adds "elasticity" to the path following and enables dynamic modification of the paths. This permits the users to compensate for changes in the environment such as introduction of new obstacles or for errors in position sensing. The experiments performed on a Scooter cobot show that users can learn to use this novel tool to modify and design guiding paths in a relatively simple way. The operators use the EPC by pushing/pulling against the guided paths to produce the desired deformations. Then, by just dropping the forces and trusting the path controller, they will be brought back to the guided paths.

  19. Endocarditis in left ventricular assist device

    Science.gov (United States)

    Thyagarajan, Braghadheeswar; Kumar, Monisha Priyadarshini; Sikachi, Rutuja R; Agrawal, Abhinav

    2016-01-01

    Summary Heart failure is one of the leading causes of death in developed nations. End stage heart failure often requires cardiac transplantation for survival. The left ventricular assist device (LVAD) has been one of the biggest evolvements in heart failure management often serving as bridge to transplant or destination therapy in advanced heart failure. Like any other medical device, LVAD is associated with complications with infections being reported in many patients. Endocarditis developing secondary to the placement of LVAD is not a frequent, serious and difficult to treat condition with high morbidity and mortality. Currently, there are few retrospective studies and case reports reporting the same. In our review, we found the most common cause of endocarditis in LVAD was due to bacteria. Both bacterial and fungal endocarditis were associated with high morbidity and mortality. In this review we will be discussing the risk factors, organisms involved, diagnostic tests, management strategies, complications, and outcomes in patients who developed endocarditis secondary to LVAD placement. PMID:27672540

  20. Right Ventricular Assist Device Configuration for Remote Decannulation.

    Science.gov (United States)

    Tchantchaleishvili, Vakhtang; Sagebin, Fabio; Massey, Howard Todd

    2016-01-01

    Preoperative risk factors, intraoperative fluid shifts, and transfusions place patients at increased risk for right ventricular failure during left ventricular assist device implantation. Despite aggressive use of inotropes and pulmonary vasodilators, in severe cases of RV failure, a right ventricular assist device may be required. For the past several years, we have been implanting right ventricular assist devices in the presented configuration, allowing less invasive removal without sternotomy. The method is presented herein.

  1. Percutaneous Ventricular Assist Devices: New Deus Ex Machina?

    Directory of Open Access Journals (Sweden)

    Diego Arroyo

    2011-01-01

    Full Text Available The development of ventricular assist devices has broadened the means with which one can treat acute heart failure. Percutaneous ventricular assist devices (pVAD have risen from recent technological advances. They are smaller, easier, and faster to implant, all important qualities in the setting of acute heart failure. The present paper briefly describes the functioning and assets of the most common devices used today. It gives an overview of the current evidence and indications for left ventricular assist device use in cardiogenic shock and high-risk percutaneous coronary intervention. Finally, extracorporeal life support devices are dealt with in the setting of hemodynamic support.

  2. Design of wheel-type walking-assist device

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Seung Ho; Kim, Seung Ho; Kim, Chang Hoi; Seo, Yong Chil; Jung, Kyung Min; Lee, Sung Uk

    2006-03-15

    In this research, a outdoor wheel-type walking-assist device is developed to help an elder having a poor muscular strength at legs for walking, sitting and standing up easily at outdoors, and also for going and downing stairs. In conceptually designing, the environments of an elder's activity, the size of an elder's body and a necessary function of helping an elder are considered. This device has 4 wheels for stability. When an elder walks in incline plane with the proposed device, a rear-wing is rotated to keep the supporting device horizontal, regardless of an angle of inclination. A height-controlling device, which can control the height of the supporting device for adjusting an elder's height, is varied vertically to help an elder to sit and stand-up easily. Moreover, a outdoor wheel-type walking-assist device is conceptually designed and is made. In order to design it, the preview research is investigated firstly. On the basis of the proposed walking-assist device, the outdoor walking-assist device is designed and made. The outdoor wheel-type walking-assist device can go and down stairs automatically. This device go up and down the stair of having maximum 20cm height and an angle of 25 degrees with maximum 4 sec/stairs speed, and move at flatland with 60cm/sec speed.

  3. A rare case of biventricular myxoma.

    Science.gov (United States)

    Ermek, Tangsakar; Aybek, Naibi; Zhang, Wei-Min; Guo, Yong-Zhong; Guo, Sheng; Mamataly, Azze; Chang, Dong-Qing; Liu, Jun; Zhang, Zong-Gang

    2017-03-27

    Cardiac myxoma is the most common primary cardiac tumor. Approximately 75-80% of myxomas are located in the left atrium. Occurrence of multiple myxomas is extremely rare. We describe a rare case of biventricular myxomas resulting in right ventricular inflow and tricuspid valve obstruction. The lesions were detected by echocardiography and thoracic computerized tomography (CT) and confirmed on positron emission tomography-computed tomography. The patient underwent successful surgical resection of the multiple cardiac myxomas. This kind of biventricular case has not been previously reported. The patient is asymptomatic as of the 10-month follow-up.

  4. Reference Device-Assisted Adaptive Location Fingerprinting

    Directory of Open Access Journals (Sweden)

    Dongjin Wu

    2016-06-01

    Full Text Available Location fingerprinting suffers in dynamic environments and needs recalibration from time to time to maintain system performance. This paper proposes an adaptive approach for location fingerprinting. Based on real-time received signal strength indicator (RSSI samples measured by a group of reference devices, the approach applies a modified Universal Kriging (UK interpolant to estimate adaptive temporal and environmental radio maps. The modified UK can take the spatial distribution characteristics of RSSI into account. In addition, the issue of device heterogeneity caused by multiple reference devices is further addressed. To compensate the measuring differences of heterogeneous reference devices, differential RSSI metric is employed. Extensive experiments were conducted in an indoor field and the results demonstrate that the proposed approach not only adapts to dynamic environments and the situation of changing APs’ positions, but it is also robust toward measuring differences of heterogeneous reference devices.

  5. Introduction of assistive devices: home nurses' practices and beliefs.

    Science.gov (United States)

    Roelands, Marc; Van Oost, Paulette; Depoorter, Anne Marie; Buysse, Ann; Stevens, Veerle

    2006-04-01

    This paper reports a study describing home nurses' intention and current practices regarding introducing assistive devices, and investigating whether their practice is related to social cognitive factors (attitudes, subjective norms and self-efficacy). Home nurses not only care for patients in particular medical domains, but also educate and guide them towards more independence. Patients with age-related disabilities in mobility and self-care might benefit from the use of assistive devices. A home nurse might be the first and only person to discuss the disability and use of an assistive device. Therefore, home nurses' beliefs about the introduction of assistive devices could affect their daily practices. A cross-sectional study was conducted with a convenience sample of 64 home nurses chosen from a random sample of home nursing departments. The home nurses completed a self-administered questionnaire. The Theory of Planned Behaviour framework was used to develop the social cognitive measures regarding each of the six steps distinguished in the introduction of assistive devices. Home nurses had positive attitudes and high levels of intention, subjective norm and self-efficacy towards most steps of the decision process to introduce assistive devices. In a multiple linear regression analysis, attitude and self-efficacy predicted intention to introduce assistive devices to older clients with disabilities. Intention was correlated to home nurses' current practices. The findings suggest that conditions are present to involve home nurses more explicitly in the introduction of assistive devices to their patients. Social cognitive factors should be taken into account when developing interventions that aim to support home nurses to do this.

  6. Design optimization of field-plate assisted RESURF devices

    NARCIS (Netherlands)

    Boksteen, B.K.; Ferrara, A.; Heringa, A.; Steeneken, P.G.; Koops, G.E.J.; Hueting, Raymond Josephus Engelbart

    2013-01-01

    A mathematical model for optimizing the 2-D potential distribution in the drift region of field-plate (FP)-assisted RESURF devices (Fig. 1) is presented. The proposed model extends earlier work [1-2] by including top-bottom dielectric asymmetry (typical in SOI devices [3]), non-zero field plate

  7. The diagnosis of left ventricular assist device thrombosis

    NARCIS (Netherlands)

    Gerds, H. Z. R.; Brugemann, J.; Rienstra, M.; Erasmus, M. E.

    The clinical course of a patient with a left ventricular assist device is described. A total of 6 weeks after device insertion, the lactate dehydrogenase (LDH) level increased to 2801 U/l despite adding low-molecular-weight heparin to acenocoumarol and aspirin. Pump thrombosis was suspected but

  8. Use of assistive technology devices in mainstream schools: students' perspective.

    Science.gov (United States)

    Hemmingsson, Helena; Lidström, Helene; Nygård, Louise

    2009-01-01

    The use and nonuse of assistive technology devices in school by students with physical disabilities was investigated, and the students' experiences in using these devices is described. We used a mixed-methods approach with predominantly qualitative methods to collect and analyze data, which included observations of and interviews with 20 students with physical disabilities and the number and type of assistive technology devices provided. It is vital that devices be integrated into educational practice and that students experience immediate benefits for their function in everyday school activities without detrimental effects on their social participation. The latter was often more important than being able to perform activities independently. The students adopted both a functional and a psychosocial perspective of their devices, and providers should neglect neither. Children and youth need both verbal information and practical experience using devices to be able to make informed decisions.

  9. Left Ventricular Assist Devices in the Management of Heart Failure

    Science.gov (United States)

    Y Birati, Edo

    2015-01-01

    Mechanical circulatory support has emerged as an important therapy for advanced heart failure, with more than 18,000 continuous flow devices implanted worldwide to date. These devices significantly improve survival and quality of life and should be considered in every patient with end-stage heart failure with reduced ejection fraction who has no other life-limiting diseases. All candidates for device implantation should undergo a thorough evaluation in order to identify those who could benefit from device implantation. Long-term management of ventricular assist device patients is challenging and requires knowledge of the characteristic complications with their unique clinical presentations. PMID:28785427

  10. Transapical miniaturized ventricular assist device: Design and initial testing

    Science.gov (United States)

    Slaughter, Mark S.; Giridharan, Guruprasad A.; Tamez, Dan; LaRose, Jeff; Sobieski, Mike A.; Sherwood, Leslie; Koenig, Steven C.

    2013-01-01

    Background Left ventricular assist devices are increasingly used to treat patients with advanced and otherwise refractory heart failure as bridge to transplant or destination therapy. We evaluated a new miniaturized left ventricular assist device that requires minimal surgery for implantation, potentially allowing implantation in earlier stage heart failure. Methods HeartWare (Miami Lakes, Fla) developed transapical miniaturized ventricular assist device. Acute (n = 4), 1-week (n = 2), and 30-day (n = 4) bovine model experiments evaluated hemodynamic efficacy and biocompatibility of the device, which was implanted through small left thoracotomy with single insertion at apex of left ventricle without cardiopulmonary bypass. The device outflow cannula was positioned across the aortic valve. The international normalized ratio was maintained between 2.0 and 2.5 with warfarin. Hemodynamic, echocardiographic, fluoroscopic, hematologic, and blood chemistry measurements were evaluated. Results The device was successfully implanted through the left ventricular apex in all 10 animals. The device was operated at 15,000 ± 1000 rpm (power consumption, 3.5–6.0 W). The device maintained normal end-organ perfusion with no significant hemolysis (0–30 mg/dL). There were no pump failures or device-related complications. At autopsy, no abnormalities were seen in endocardium, aortic valve leaflets, or aortic root. There was no evidence of thromboembolism or abnormalities in any peripheral end organs. Conclusions We successfully demonstrated feasibility of a novel intraventricular assist device that can be completely implanted through left ventricular apex. This transapical surgical approach eliminates needs for sternotomy, device pocket, cardiopulmonary bypass, ventricular coring, and construction of an outflow graft anastomosis. PMID:21320708

  11. Biventricular capture verification by means of morphological analysis of intracardiac electrogram.

    Science.gov (United States)

    Lian, Jie; Garner, Garth; Muessig, Dirk

    2013-11-01

    The aim of this study is to develop a new feature for automatic biventricular capture verification in cardiac resynchronization therapy (CRT) devices, by means of morphological analysis of the intracardiac electrogram (IEGM). The algorithm performs capture classification based on a novel adaptive signed correlation index (ASCI), which measures morphological similarity between the post-pace IEGM and a template waveform representing captured paces. To evaluate the performance of the algorithm, CRT pacemakers were implanted in six dogs. During a mean follow-up of 23 days, 175 biventricular threshold tests were conducted with various configurations of pace/sense polarities. Biventricular IEGMs were recorded and downloaded for offline analysis. Template signals for each pace/sense configuration in each chamber were created for individual dogs during the first follow-up. Each pace was annotated for capture or non-capture by visual examination of the IEGM. A total of 9991 capture paces and 4474 non-capture paces were included for morphological analysis. The calculated ASCI values were well separated for capture and non-capture paces irrespective of right/left pacing chambers, pace/sense configurations, pacing amplitude, individual dogs, and temporal proximity of the capture templates. Overall, the classification accuracy of the algorithm remained ≥99% for any ASCI cut-off value choosing between 0.18 and 0.52. This study demonstrated the feasibility to perform automatic biventricular capture verification based on morphological analysis of the IEGM.

  12. Right ventricular assist device with membrane oxygenator support for right ventricular failure following implantable left ventricular assist device placement.

    Science.gov (United States)

    Leidenfrost, Jeremy; Prasad, Sunil; Itoh, Akinobu; Lawrance, Christopher P; Bell, Jennifer M; Silvestry, Scott C

    2016-01-01

    Cardiogenic shock from refractory right ventricular (RV) failure during left ventricular assist device placement is associated with high morbidity and mortality. The addition of extracorporeal membrane oxygenation to RV mechanical assistance may help RV recovery and lead to improved outcomes. We retrospectively reviewed all implanted continuous-flow left ventricular assist devices from April 2009 to June 2013. RV mechanical support was utilized for RV failure defined as haemodynamic instability despite vasopressors, pulmonary vascular dilators and inotropic therapy. RV assist devices were utilized with and without in-line membrane oxygenation. During the study period, 267 continuous-flow left ventricular assist devices were implanted. RV mechanical support was utilized in 27 (10%) patients; 12 (46%) had the addition of in-line extracorporeal membrane oxygenation. The mean age of patients with a right ventricular assist device with membrane oxygenation was lower than that in patients with a right ventricular assist device alone (45.6 ± 15.9 vs 64.6 ± 6.5, P = 0.001). Support was weaned in 66% (10 of 15) of patients with right ventricular assist device (RVAD) alone vs 83% (10 of 12) of those with RVAD with membrane oxygenation (P = 0.42). The RVAD was removed after 10.4 ± 9.4 vs 5 ± 2.99 days for patients with a RVAD with membrane oxygenation (P = 0.1). Patients with RVAD with membrane oxygenation had a 30-day mortality rate of 8 vs 47% for those with RVAD alone (P = 0.04). The survival rate after discharge was 86, 63 and 54% at 3, 6 and 12 months for both groups combined. Patients with a RVAD with membrane oxygenation support for acute RV failure after continuous-flow left ventricular assist device implantation had a lower 30-day mortality than those with a RVAD alone. Patients who survive to discharge have a reasonable 1-year survival. Combining membrane oxygenation with RVAD support appears to offer a short-term survival benefit in patients with RV failure

  13. Human Grasp Assist Device Soft Goods

    Science.gov (United States)

    Ihrke, Chris A. (Inventor); Davis, Donald R. (Inventor); Linn, Douglas Martin (Inventor); Bergelin, Bryan (Inventor); Bridgwater, Lyndon B. J. (Inventor); Bibby, Heather (Inventor); Schroeder, Judy (Inventor); Erkkila, Craig (Inventor)

    2015-01-01

    A grasp assist system includes a glove and a flexible sleeve. The glove includes a digit such as a finger or thumb, a force sensor configured to measure a grasping force applied to an object by an operator wearing the glove, and adjustable phalange rings positioned with respect to the digit. A saddle is positioned with respect to the finger. A flexible tendon is looped at one end around the saddle. A conduit contains the tendon. A conduit anchor secured within a palm of the glove receives the conduit. The sleeve has pockets containing an actuator assembly connected to another end of the tendon and a controller. The controller is in communication with the force sensor, and calculates a tensile force in response to the measured grasping force. The controller commands the tensile force from the actuator assembly to tension the tendon and thereby move the finger.

  14. Human Grasp Assist Device With Exoskeleton

    Science.gov (United States)

    Bergelin, Bryan J (Inventor); Ihrke, Chris A. (Inventor); Davis, Donald R. (Inventor); Linn, Douglas Martin (Inventor); Bridgwater, Lyndon B. J. (Inventor)

    2014-01-01

    A grasp assist system includes a glove, actuator assembly, and controller. The glove includes a digit, i.e., a finger or thumb, and a force sensor. The sensor measures a grasping force applied to an object by an operator wearing the glove. Phalange rings are positioned with respect to the digit. A flexible tendon is connected at one end to one of the rings and is routed through the remaining rings. An exoskeleton positioned with respect to the digit includes hinged interconnecting members each connected to a corresponding ring, and/or a single piece of slotted material. The actuator assembly is connected to another end of the tendon. The controller calculates a tensile force in response to the measured grasping force, and commands the tensile force from the actuator assembly to thereby pull on the tendon. The exoskeleton offloads some of the tensile force from the operator's finger to the glove.

  15. 78 FR 34922 - Definition of Auditory Assistance Device

    Science.gov (United States)

    2013-06-11

    ... marketplace provides the best measure for determining which technology is optimal for addressing the... the life of the equipment. It decided that requiring the upgrade or replacement of existing part 15... be permitted to operate their existing part 15 auditory assistance devices until replacement is...

  16. Monitoring mobility assistive device use in post-stroke patients

    DEFF Research Database (Denmark)

    Boissy, Patrice; Hester, Todd; Sherrill, Delsey

    2007-01-01

    Mobility assistive devices (MAD) such as canes can improve mobility and allow independence in the performance of mobility-related tasks. The use of MAD is often prescribed for stroke survivors. Despite their acknowledged qualities, MAD in real life conditions are typically underutilized, misused ...

  17. Patient-reported outcomes in left ventricular assist device therapy

    DEFF Research Database (Denmark)

    Brouwers, Corline; Denollet, Johan; de Jonge, Nicolaas

    2011-01-01

    Technological advancements of left ventricular assist devices (LVAD) have created today's potential for extending the lives of patients with end-stage heart failure. Few studies have examined the effect of LVAD therapy on patient-reported outcomes (PROs), such as health status, quality of life...

  18. 76 FR 61655 - Definition of Part 15 Auditory Assistance Device

    Science.gov (United States)

    2011-10-05

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 15 [ET Docket No. 10-26; FCC 11-133] Definition of.... SUMMARY: This document proposes to amend the definition of ``auditory assistance device'' in the... interpretation, where the spoken words are translated continuously in near real time. This action is taken in...

  19. Ventricular assist devices: Pharmacological aspects of a mechanical therapy

    Science.gov (United States)

    Wever-Pinzon, O.; Stehlik, J.; Kfoury, A.G.; Terrovitis, J.V.; Diakos, N.A.; Charitos, C.; Li, D.Y.; Drakos, S.G.

    2013-01-01

    Heart failure (HF) is a global epidemic that continues to cause significant morbidity and mortality despite advances in medical therapy. Ventricular assist device technology has emerged as a therapeutic option to bridge patients with end-stage HF to heart transplantation or as an alternative to transplantation in selected patients. In some patients, mechanical unloading induced by ventricular assist devices leads to improvement of myocardial function and a possibility of device removal. The implementation of this advanced technology requires multiple pharmacological interventions, both in the perioperative and long-term periods, in order to minimize potential complications and improve patient outcomes. We herein review the latest available evidence supporting the use of specific pharmacological interventions and current practices in the care of these patients: anticoagulation, bleeding management, pump thrombosis, infections, arrhythmias, right ventricular failure, hypertension, desensitization protocols, among others. Areas of uncertainty and ground for future research are also highlighted. PMID:22281238

  20. Modelo experimental para treinamento com dispositivo de assistência ventricular pulsátil Experimental ventricular assist device to maintain cardiocirculatory conditions

    Directory of Open Access Journals (Sweden)

    Maurício Galantier

    1995-09-01

    Full Text Available Os dispositivos de Assistência Ventricular (D A V têm sido utilizados para permitir a manutenção de condições cardiocirculatórias em dois tipos de situações: 1- Como ponte para transplante cardíaco em paciente candidato e que, na espera de doador apropriado, tem suas condições cardiocirculatórias muito deterioradas. 2- Como suporte circulatório em situações agudas em que se prevê uma possível recuperação funcional do coração, como em miocardites agudas, miocardiopatia puerperal, falência miocárdica pós cardiotomia, rejeição aguda pós transplante cardíaco etc. Entre os vários dispositivos utilizados, o modelo descrito por Pierce-Donachy, desenvolvido pela Thoratec Laboratories Corporation, consiste em aparelho de fluxo pulsátil, pneumático, externo, podendo ser usado como suporte uni ou biventricular. O ventrículo artificial é acionado por um módulo que permite vários ajustes manuais ou mesmo automáticos para melhor adequação às diferentes condições clínicas do paciente. O treinamento para utilização do dispositivo implica na integração de vários setores, como cirurgiões, intensivistas, enfermeiras, biomédicos e eletrotécnicos, necessitando laboratório especializado, com o uso de animais de maior porte, de custo elevado e manuseio complicado, dificultando a repetição freqüente dos experimentos. Os autores desenvolveram um modelo experimental, constituído por um coração bovino conectado pelo átrio esquerdo e pela aorta a um circuito de circulação extracorpórea. Através de técnica cirúrgica padronizada, são instaladas as cânulas apropriadas; as mesmas são conectadas ao ventrículo artificial e este ao módulo de acionamento. Com este modelo podese, de maneira simples, didática e reprodutível, efetuar o treinamento de aspectos técnicos de implante, manuseio de módulo de acionamento e simulação de situações clínicas e emergenciaisThe Ventricular Assist Devices (V A D have

  1. Network-Assisted Device-to-Device (D2D) Direct Proximity Discovery with Underlay Communication

    DEFF Research Database (Denmark)

    Pratas, Nuno; Popovski, Petar

    2015-01-01

    Device-to-Device communications are expected to play an important role in current and future cellular generations, by increasing the spatial reuse of spectrum resources and enabling lower latency communication links. This paradigm has two fundamental building blocks: (i) proximity discovery and (ii......) direct communication between proximate devices. While (ii) is treated extensively in the recent literature, (i) has received relatively little attention. In this paper we analyze a network-assisted underlay proximity discovery protocol, where a cellular device can take the role of: announcer (which...... guaranteeing both reliable downlink transmissions and underlay proximity discovery....

  2. Assistive listening devices drive neuroplasticity in children with dyslexia

    Science.gov (United States)

    Hornickel, Jane; Zecker, Steven G.; Bradlow, Ann R.; Kraus, Nina

    2012-01-01

    Children with dyslexia often exhibit increased variability in sensory and cognitive aspects of hearing relative to typically developing peers. Assistive listening devices (classroom FM systems) may reduce auditory processing variability by enhancing acoustic clarity and attention. We assessed the impact of classroom FM system use for 1 year on auditory neurophysiology and reading skills in children with dyslexia. FM system use reduced the variability of subcortical responses to sound, and this improvement was linked to concomitant increases in reading and phonological awareness. Moreover, response consistency before FM system use predicted gains in phonological awareness. A matched control group of children with dyslexia attending the same schools who did not use the FM system did not show these effects. Assistive listening devices can improve the neural representation of speech and impact reading-related skills by enhancing acoustic clarity and attention, reducing variability in auditory processing. PMID:22949632

  3. Friction control of mechanical seals in a ventricular assist device

    Directory of Open Access Journals (Sweden)

    K. Kanda

    2015-06-01

    Full Text Available Low and stable friction is required for mechanical seals in implantable ventricular assist devices. In this study, a specialized test apparatus was designed to test the frictional properties of a mechanical seal in blood in implantable ventricular assist devices. It was shown that a blood-derived protein film forms on the sealing surfaces and causes higher and unstable friction than that in water. Further, it was shown that concave surface features on the substrate initially catch aggregated proteins that are denatured by friction, thus the protein film progresses from concave to flat regions on the substrate. On the basis of this protein film formation mechanism, the creation of a smooth, hydrophilic sealing surface was proposed to control friction and its effectiveness was validated.

  4. Concomitant Thoracic Aortobifemoral Bypass With Left Ventricular Assist Device Implantation.

    Science.gov (United States)

    Bishawi, Muath; Shah, Asad A; McCann, Richard L; Milano, Carmelo A

    2016-11-01

    Improved quality of life for patients after left ventricular assist device (LVAD) implantation can be greatly limited by peripheral vascular disease even if heart failure symptoms are resolved by LVAD support. We present a case of concomitant thoracic aortobifemoral bypass and LVAD implantation in a patient with ischemic cardiomyopathy, severe peripheral vascular disease, and multiple previous failed revascularization attempts. In this patient, we used the LVAD outflow to provide the inflow to the femoral artery bypass graft. This graft has remained patent at a 2-year follow-up, without claudication symptoms. Performing concomitant major vascular operations safely and successfully is feasible in patients with LVADs. Quality of life after ventricular assist device placement can be limited by vascular disease, but it can be markedly improved after vascular surgical intervention. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Focused microwave-assisted Soxhlet extraction: devices and applications.

    Science.gov (United States)

    Luque-García, J L; Luque de Castro, M D

    2004-10-20

    An overview of a new extraction technique called focused microwave-assisted Soxhlet extraction (FMASE) is here presented. This technique is based on the same principles as conventional Soxhlet extraction but using microwaves as auxiliary energy to accelerate the process. The different devices designed and constructed so far, their advantages and limitations as well as their main applications on environmental and food analysis are discussed in this article.

  6. Advanced patient transfer assist device with intuitive interaction control.

    Science.gov (United States)

    Humphreys, Heather C; Choi, Young Mi; Book, Wayne J

    2017-10-24

    This research aims to improve patient transfers by developing a new type of advanced robotic assist device. It has multiple actuated degrees of freedom and a powered steerable base to maximize maneuverability around obstacles. An intuitive interface and control strategy allows the caregiver to simply push on the machine in the direction of desired patient motion. The control integrates measurements of both force and proximity to mitigate any potential large collision forces and provides operators information about obstacles with a form of haptic feedback. Electro-hydraulic pump controlled actuation provides high force density for the actuation. Nineteen participants performed tests to compare transfer operations (transferring a 250-lb mannequin between a wheelchair, chair, bed, and floor) and interaction control of a prototype device with a commercially available patient lift. The testing included a time study of the transfer operations and subjective rating of device performance. The results show that operators perform transfer tasks significantly faster and rate performance higher using the prototype patient transfer assist device than with a current market patient lift. With further development, features of the new patient lift can help facilitate patient transfers that are safer, easier, and more efficient for caregivers.

  7. Modeling Users, Context and Devices for Ambient Assisted Living Environments

    Science.gov (United States)

    Castillejo, Eduardo; Almeida, Aitor; López-de-Ipiña, Diego; Chen, Liming

    2014-01-01

    The participation of users within AAL environments is increasing thanks to the capabilities of the current wearable devices. Furthermore, the significance of considering user's preferences, context conditions and device's capabilities help smart environments to personalize services and resources for them. Being aware of different characteristics of the entities participating in these situations is vital for reaching the main goals of the corresponding systems efficiently. To collect different information from these entities, it is necessary to design several formal models which help designers to organize and give some meaning to the gathered data. In this paper, we analyze several literature solutions for modeling users, context and devices considering different approaches in the Ambient Assisted Living domain. Besides, we remark different ongoing standardization works in this area. We also discuss the used techniques, modeled characteristics and the advantages and drawbacks of each approach to finally draw several conclusions about the reviewed works. PMID:24643006

  8. Limitations to Chronic Right Ventricular Assist Device Support.

    Science.gov (United States)

    Karimov, Jamshid H; Sunagawa, Gengo; Horvath, David; Fukamachi, Kiyotaka; Starling, Randall C; Moazami, Nader

    2016-08-01

    Failure of the right ventricle represents a significant clinical problem and may have different causes, with rates varying between 5% and 50% in patients supported by a left ventricular assist device (LVAD). However, treatment options and device development for right ventricular failure (RVF) have significantly lagged behind those for LVADs. Newer technologies designed or adapted for RV support are needed to provide adequate long-term circulatory support. In this review, we discuss (1) the significance of RVF and its physiologic implications, (2) device constraints affecting treatment options for RVF, and (3) implantable VADs potentially available for RV support. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Delineating survival outcomes in children Ventricular Assist Device.

    Science.gov (United States)

    Conway, Jennifer; St Louis, James; Morales, David L S; Law, Sabrina; Tjossem, Christine; Humpl, Tilman

    2015-01-01

    The goal of this study was to delineate outcomes of children weighing Ventricular Assist Device (EXCOR Pediatric, Berlin Heart Inc., The Woodlands, Texas) and to identify factors that increased the risk of all-cause mortality in this population. Ventricular assist devices have been shown to be an effective bridge to transplant, with improved outcomes compared with use of extracorporeal membrane oxygenation. Smaller patients may be at greatest risk for poor outcomes, but it remains unclear if mortality is uniform across all smaller candidates. Patients included in the analysis were part of a multicenter prospective cohort study examining the use of the Berlin Heart EXCOR Pediatric Ventricular Assist Device as a bridge to transplant. All children who received the device between May 9, 2007 and December 31, 2010, and who were enrolled in the sponsor's U.S. regulatory database, were identified and analyzed. Multivariable analysis was performed to determine risk factors associated with mortality. A total of 97 children weighing <10 kg were included (median age 6.2 months; median weight 6.2 kg; median duration of support 26 days). Successful outcomes were achieved in 56.7% of patients. Independent risk factors for mortality in smaller children included pre-existing congenital heart disease (odds ratio: 4.8 [95% confidence interval: 1.5 to 15.0]; p = 0.007) and an elevated bilirubin level (odds ratio: 5.3 [95% confidence interval: 2.0 to 14.3]; p = 0.001). Overall results for children weighing <10 kg were inferior to those of their larger counterparts. This outcome was primarily influenced by congenital heart disease and presence of elevated pre-implant bilirubin levels. These factors should be taken into consideration at decision making because reasonable outcomes can be achieved in a select population of children weighing <10 kg. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  10. Pediatric ventricular assist devices: current challenges and future prospects

    Science.gov (United States)

    Burki, Sarah; Adachi, Iki

    2017-01-01

    The field of mechanical circulatory support has made great strides in the preceding 2 decades. Although pediatric mechanical circulatory support has lagged behind that of adults, the gap between them is expected to close soon. The only device currently approved by the US Food and Drug Administration for use in children is the Berlin Heart EXCOR ventricular assist device (VAD). The prospective Berlin Heart Investigational Device Exemption Trial demonstrated good outcomes, such as bridge to transplantation or recovery, in ~90% of children supported with this device. However, a high incidence of hemorrhagic and thrombotic complications was also noted. As a result, pediatric centers have just started implanting adult intracorporeal continuous-flow devices in children. This paradigm shift has opened a new era in pediatric mechanical circulatory support. Whereas children on VAD were previously managed exclusively in hospital, therapeutic options such as outpatient management and even destination therapy have been becoming a reality. With continued miniaturization and technological refinements, devices currently in development will broaden the range of options available to children. The HeartMate 3 and HeartWare MVAD are two such compact VADs, which are anticipated to have great potential for pediatric use. Additionally, a pediatric-specific continuous-flow VAD, the newly redesigned Jarvik Infant 2015, is currently undergoing preclinical testing and is expected to undergo a randomized clinical trial in the near future. This review aims to discuss the challenges posed by the use of intracorporeal adult continuous-flow devices in children, as well as to provide our perspective on the future prospects of the field of pediatric VADs. PMID:28546755

  11. Robot-assisted repair of diaphragmatic hernias following ventricular assist device implantation.

    Science.gov (United States)

    Ongele, M O; Benrashid, E; Gilmore, B F; Schroder, J; Hartwig, M; Zani, S

    2018-02-01

    Use of ventricular assist devices (VADs) is increasingly common, as is the need for surgeons to be familiar with the management of common complications in this population. Nonetheless, repair of diaphragmatic hernias which commonly develop following VAD implantation remains technically challenging due to intra-abdominal adhesions and the proximity of vital structures. Despite the potential benefits of improved dexterity and visualization, robotic approaches have thus far not been used to address this. We present the first two described cases of robot-assisted repair of diaphragmatic hernias in the setting of prior or current VAD placement.

  12. FOLFOX Induced Takotsubo Cardiomyopathy Treated with Impella Assist Device

    Directory of Open Access Journals (Sweden)

    Swethika Sundaravel

    2017-01-01

    Full Text Available Chemotherapy induced cardiotoxicity is becoming increasingly prevalent with several new agents being used recently. The incidence of Takotsubo cardiomyopathy due to 5-fluorouracil based chemotherapeutic regimens like FOLFOX is not uncommon. It is also seen with platinum based chemotherapy. Most of these patients have reversible cardiotoxicity and the cardiac function recovers within a short period with supportive treatment. Here we have a patient who presented with cardiogenic shock after 5 days of receiving FOLFOX regimen for colorectal adenocarcinoma. She was treated with a percutaneous left ventricular assist device, Impella CP, for hemodynamic support with excellent outcome.

  13. Left ventricular assist device therapy in advanced heart failure

    DEFF Research Database (Denmark)

    Gustafsson, Finn; Rogers, Joseph G

    2017-01-01

    when deciding on LVAD implantation such as age, co-morbidity, and cardiac pathophysiology. Complications to LVAD therapy are reviewed. It is concluded that while complications with LVAD therapy are not uncommon, most are manageable, and current outcomes clearly justify use of LVADs in advanced HF....... to shortage of donor organs. Implantable left ventricular assist device (LVAD) technology has improved considerably, and the currently used continuous flow devices may last >10 years in a patient. LVADs are being used increasingly both as bridge-to-transplantation and as destination therapy. Current studies...... report 1- and 2-year survival after LVAD implantation of 80% and 70%, respectively. Outcome after LVAD implantation in stable patients is superior to that of 'crash and burn' patients or patients sliding on inotropes, favouring early referral and implantation. This review summarizes factors to consider...

  14. Simulating Pediatric Ventricular Assist Device Operation Using Fluid Structure Interaction

    Science.gov (United States)

    Long, Chris; Bazilevs, Yuri; Marsden, Alison

    2012-11-01

    Ventricular Assist Devices (VADs) provide mechanical circulatory support to patients in heart failure. They are primarily used to extend life until cardiac transplant, but also show promise as a ``bridge-to-recovery'' device in pediatric patients. Commercially available pediatric pumps are pulsatile displacement pumps, with two distinct chambers for air and blood separated by a thin, flexible membrane. The air chamber pneumatically drives the membrane, which drives blood through the other chamber via displacement. The primary risk factor associated with these devices is stroke or embolism due to thrombogenesis in the blood chamber, occurring in as many as 40% of patients. Our goal is to perform simulations that accurately model the hemodynamics of the device, as well as the non-linear membrane buckling. We apply a finite-element based fluid solver, with an Arbitrary Lagrangian-Eulerian (ALE) framework to account for mesh motion. Isogeometric Analysis with a Kirchhoff-Love shell formulation is used on the membrane, and two distinct fluid subdomains are used for the air and blood chambers. The Fluid Structure Interaction (FSI) problem is solved simultaneously, using a Matrix Free method to model the interactions at the fluid-structure boundary. Methods and results are presented.

  15. Percutaneous Ventricular Assist Devices: A Health Technology Assessment

    Science.gov (United States)

    Lee, Christine; Djalalov, Sandjar; Xie, Xuanqian; Holubowich, Corinne

    2017-01-01

    Background Percutaneous coronary intervention (PCI)—using a catheter to place a stent to keep blood vessels open—is increasingly used for high-risk patients who cannot undergo surgery. Cardiogenic shock (when the heart suddenly cannot pump enough blood) is associated with a high mortality rate. The percutaneous ventricular assist device can help control blood pressure and increase blood flow in these high-risk conditions. This health technology assessment examined the benefits, harms, and budget impact of the Impella percutaneous ventricular assist device in high-risk PCI and cardiogenic shock. We also analyzed cost-effectiveness of the Impella device in high-risk PCI. Methods We performed a systematic search of the literature for studies examining the effects of the Impella percutaneous ventricular assist device in high-risk PCI and cardiogenic shock, and appraised the evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria, focusing on hemodynamic stability, mortality, major adverse cardiac events, bleeding, and vascular complications. We developed a Markov decision-analytical model to assess the cost- effectiveness of Impella devices versus intra-aortic balloon pumps (IABPs), calculated incremental cost-effectiveness ratios (ICERs) using a 10-year time horizon, and conducted sensitivity analyses to examine the robustness of the estimates. The economic model was conducted from the perspective of the Ontario Ministry of Health and Long-Term Care. Results Eighteen studies (one randomized controlled trial and 10 observational studies for high-risk PCI, and one randomized controlled trial and six observational studies for cardiogenic shock) were included in the clinical review. Compared with IABPs, Impella 2.5, one model of the device, improved hemodynamic parameters (GRADE low–very low) but showed no significant difference in mortality (GRADE low), major adverse cardiac events (GRADE low

  16. Prototype ventricular assist device supported on magnetic bearings

    Energy Technology Data Exchange (ETDEWEB)

    Allaire, P.E.; Maslen, E.H. [Univ. of Virginia, Charlottesville, VA (United States); Kim, H.C.; Olsen, D.B.; Bearnson, G.D. [Univ. of Utah, Salt Lake City, UT (United States)

    1995-12-31

    Mechanical artificial hearts are now expected to be used as assist or total replacements for failing human hearts, if a reliable, anatomically appropriate design is developed. Initially, ventricular assist or total replacement devices were pulsatile air driven units containing a flexing polymeric diaphragm and two valves for each ventricle. Many reliability problems were encountered. Recently, attention has been focused on axial or centrifugal continuous flow blood pumps. Magnetic bearings employed in such devices offer the advantages of no required lubrication and large operating clearances. This paper describes a prototype continuous flow pump supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. It delivered 6 liters/min of flow at 100 mm Hg differential head operating at 2,400 rpm in water. The pump is totally magnetically supported in four magnetic bearings - two radial and two thrust. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity, current gains, and open loop stiffness are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water.

  17. Feasibility of a pumpless extracorporeal respiratory assist device.

    Science.gov (United States)

    De Somer, F; Van Belleghem, Y; Foubert, L; Caes, F; François, K; Dubrulle, F; Van Nooten, G

    1999-10-01

    Our study evaluated the efficacy and feasibility of a pumpless respiratory assist device and determined its capacity for carbon dioxide removal. In five adult pigs the left femoral vein and artery were cannulated with a 20F cannula and connected to a low-pressure hollow-fiber artificial lung. After we had obtained baseline values of mean arterial pressure, cardiac output, and blood flow across the artificial lung, the mean arterial pressure was reduced 20% and 40% relative to baseline; in a second phase, it was raised 20% and 40. Cardiac output and artificial lung flow were simultaneously recorded. We determined the carbon dioxide removal capacity of the artificial lung by gradually increasing the arterial partial carbon dioxide tension of the animal. An increase of 10 mm Hg in mean arterial pressure resulted in an increase of flow of 0.14 L/min. The mean pressure drop across the artificial lung was measured at 17 +/- 9 mm Hg. The shunt flow over the artificial lung varied between 14 and 25% of the cardiac output of the animal. Depending on inlet conditions, carbon dioxide removal by the artificial lung was between 62 +/- 22 mL/L/min and 104 +/- 25 mL/L/min. A pumpless respiratory assist device can remove a significant proportion of the metabolic carbon dioxide production. However, adequate mean arterial pressure is mandatory to maintain sufficient flow across the device. The technique seems attractive because of its simplicity and can be used in acute lung injury in conjunction of apneic oxygenation for prolonged respiratory support.

  18. An Implantable Intravascular Pressure Sensor for a Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Luigi Brancato

    2016-08-01

    Full Text Available The aim of this study is to investigate the intravascular application of a micro-electro-mechanical system (MEMS pressure sensor to directly measure the hemodynamic characteristics of a ventricular assist device (VAD. A bio- and hemo-compatible packaging strategy is implemented, based on a ceramic thick film process. A commercial sub-millimeter piezoresistive sensor is attached to an alumina substrate, and a double coating of polydimethylsiloxane (PDMS and parylene-C is applied. The final size of the packaged device is 2.6 mm by 3.6 mm by 1.8 mm. A prototype electronic circuit for conditioning and read-out of the pressure signal is developed, satisfying the VAD-specific requirements of low power consumption (less than 14.5 mW in continuous mode and small form factor. The packaged sensor has been submitted to extensive in vitro tests. The device displayed a temperature-independent sensitivity (12 μ V/V/mmHg and good in vitro stability when exposed to the continuous flow of saline solution (less than 0.05 mmHg/day drift after 50 h. During in vivo validation, the transducer has been successfully used to record the arterial pressure waveform of a female sheep. A small, intravascular sensor to continuously register the blood pressure at the inflow and the outflow of a VAD is developed and successfully validated in vivo.

  19. Fluid Structure Interaction Simulations of Pediatric Ventricular Assist Device Operation

    Science.gov (United States)

    Long, Chris; Marsden, Alison; Bazilevs, Yuri

    2011-11-01

    Pediatric ventricular assist devices (PVADs) are used for mechanical circulatory support in children with failing hearts. They can be used to allow the heart to heal naturally or to extend the life of the patient until transplant. A PVAD has two chambers, blood and air, separated by a flexible membrane. The air chamber is pressurized, which drives the membrane and pumps the blood. The primary risk associated with these devices is stroke or embolism from thrombogenesis. Simulation of these devices is difficult due to a complex coupling of two fluid domains and a thin membrane, requiring fluid-structure interaction modeling. The goal of this work is to accurately simulate the hemodynamics of a PVAD. We perform FSI simulations using an Arbitrary Lagrangian-Eulerian (ALE) finite element framework to account for large motions of the membrane and the fluid domains. The air, blood, and membrane are meshed as distinct subdomains, and a method for non-matched discretizations at the fluid-structure interface is presented. The use of isogeometric analysis to model the membrane mechanics is also discussed, and the results of simulations are presented.

  20. Timing of temporary right ventricular assist device insertion for severe right heart failure after left ventricular assist device implantation.

    Science.gov (United States)

    Takeda, Koji; Naka, Yoshifumi; Yang, Jonathan A; Uriel, Nir; Colombo, Paolo C; Jorde, Ulrich P; Takayama, Hiroo

    2013-01-01

    Data on how the timing of a temporary right ventricular assist device (RVAD) insertion affects outcome are limited in patients receiving left ventricular assist device (LVAD). Of the 282 patients who underwent LVAD placement between January 2000 and November 2010, 40 (14%) required concomitant (n = 26) or delayed (n = 14) RVAD insertion as temporary support. We analyzed early and 1-year outcomes. Preoperative variables were similar in the concomitant and delayed RVAD groups. The hospital mortality rate was approximately 50% in both groups (p = 0.82). The 1-year actuarial survival was similar in both groups (p = 0.42). Patients who required RVAD support had higher in-hospital mortality and worse 1-year survival rates than those who received LVAD only (48% vs. 9.5%, p < 0.0001; 40% vs. 82%, p < 0.0001). Multivariate logistic regression analysis indicated RVAD use as a significant risk factor for 1-year mortality (odds ratio, 18; p = 0.0003; 95% confidence interval, 3.765-86.74). Timing of temporary RVAD insertion did not affect overall survival. Necessity of RVAD support is associated with significantly worse early and late mortality at any rate. The decision to place the RVAD can be made once it is clinically necessary.

  1. Grasp Assist Device with Shared Tendon Actuator Assembly

    Science.gov (United States)

    Ihrke, Chris A. (Inventor); Bergelin, Bryan J. (Inventor); Bridgwater, Lyndon (Inventor)

    2015-01-01

    A grasp assist device includes a glove with first and second tendon-driven fingers, a tendon, and a sleeve with a shared tendon actuator assembly. Tendon ends are connected to the respective first and second fingers. The actuator assembly includes a drive assembly having a drive axis and a tendon hook. The tendon hook, which defines an arcuate surface slot, is linearly translatable along the drive axis via the drive assembly, e.g., a servo motor thereof. The flexible tendon is routed through the surface slot such that the surface slot divides the flexible tendon into two portions each terminating in a respective one of the first and second ends. The drive assembly may include a ball screw and nut. An end cap of the actuator assembly may define two channels through which the respective tendon portions pass. The servo motor may be positioned off-axis with respect to the drive axis.

  2. Left ventricular assist device hemolysis leading to dysphagia.

    Science.gov (United States)

    Wuschek, Alexander; Iqbal, Sara; Estep, Jerry; Quigley, Eamonn; Richards, David

    2015-05-14

    A 41-year-old man with a continuous-flow left ventricular assist device presented for evaluation of dysphagia and dark urine. He was found to have a significantly elevated L-lactate dehydrogenase and an elevated plasma free hemoglobin consistent with intravascular hemolysis. After the hemolysis ceased, both the black urine and dysphagia resolved spontaneously. Transient esophageal dysfunction, as a manifestation of gastrointestinal dysmotility, is known to occur in the setting of hemolysis. Paroxysmal nocturnal hemoglobinuria is another recognized cause of massive hemolysis with gastrointestinal dysmotility occurring in 25%-35% of patients during a paroxysm. Intravascular hemolysis increases plasma free hemoglobin, which scavenges nitric oxide (NO), an important second messenger for smooth muscle cell relaxation. The decrease in NO can lead to esophageal spasm and resultant dysphagia. In our patient the resolution of hemolysis resulted in resolution of dysphagia.

  3. Memory-assisted measurement-device-independent quantum key distribution

    Science.gov (United States)

    Panayi, Christiana; Razavi, Mohsen; Ma, Xiongfeng; Lütkenhaus, Norbert

    2014-04-01

    A protocol with the potential of beating the existing distance records for conventional quantum key distribution (QKD) systems is proposed. It borrows ideas from quantum repeaters by using memories in the middle of the link, and that of measurement-device-independent QKD, which only requires optical source equipment at the user's end. For certain memories with short access times, our scheme allows a higher repetition rate than that of quantum repeaters with single-mode memories, thereby requiring lower coherence times. By accounting for various sources of nonideality, such as memory decoherence, dark counts, misalignment errors, and background noise, as well as timing issues with memories, we develop a mathematical framework within which we can compare QKD systems with and without memories. In particular, we show that with the state-of-the-art technology for quantum memories, it is potentially possible to devise memory-assisted QKD systems that, at certain distances of practical interest, outperform current QKD implementations.

  4. Fluid-structure interaction simulation of pulsatile ventricular assist devices

    Science.gov (United States)

    Long, C. C.; Marsden, A. L.; Bazilevs, Y.

    2013-11-01

    In this paper we present a collection of fluid-structure interaction (FSI) computational techniques that enable realistic simulation of pulsatile Ventricular Assist Devices (VADs). The simulations involve dynamic interaction of air, blood, and a thin membrane separating the two fluids. The computational challenges addressed in this work include large, buckling motions of the membrane, the need for periodic remeshing of the fluid mechanics domain, and the necessity to employ tightly coupled FSI solution strategies due to the very strong added mass effect present in the problem. FSI simulation of a pulsatile VAD at realistic operating conditions is presented for the first time. The FSI methods prove to be robust, and may be employed in the assessment of current, and the development of future, pulsatile VAD designs.

  5. Inhaled Milrinone After Left Ventricular Assist Device Implantation.

    Science.gov (United States)

    Haglund, Nicholas A; Burdorf, Adam; Jones, Tara; Shostrom, Valerie; Um, John; Ryan, Timothy; Shillcutt, Sasha; Fischer, Patricia; Cox, Zachary L; Raichlin, Eugenia; Anderson, Daniel R; Lowes, Brian D; Dumitru, Ioana

    2015-10-01

    Proven strategies to reduce right ventricular (RV) dysfunction after continuous-flow left ventricular assist device (CF-LVAD) implantation are lacking. We sought to evaluate the tolerability, feasibility, efficacy, and pharmacokinetics of inhaled milrinone (iMil) delivery after CF-LVAD implantation. We prospectively evaluated fixed-dose nebulized iMil delivered into a ventilator circuit for 24 hours in 10 postoperative CF-LVAD (Heartmate-II) patients. Tolerability (arrhythmias, hypotension, and hypersensitivity reaction), efficacy (hemodynamics), pharmacokinetics (plasma milrinone levels), and cost data were collected.Mean age was 56 ± 9 years, 90% were male, and mean INTERMACS profile was 2.5 ± 0.8. No new atrial arrhythmia events occurred, although 3 (30%) ventricular tachycardia (1 nonsustained, 2 sustained) events occurred. Sustained hypotension, drug hypersensitivity, death, or need for right ventricular assist device were not observed. Invasive mean pulmonary arterial pressure from baseline to during iMil therapy was improved (P = .017). Mean plasma milrinone levels (ng/mL) at baseline, and 1, 4, 8, 12, and 24 hours were 74.2 ± 35.4, 111.3 ± 70.9, 135.9 ± 41.5, 205.0 ± 86.7, 176.8 ± 61.3 187.6 ± 105.5, respectively. Reduced institutional cost was observed when iMil was compared with nitric oxide therapy over 24 hours ($165.29 vs $1,944.00, respectively). iMil delivery after CF-LVAD implantation was well tolerated, feasible, and demonstrated favorable hemodynamic, pharmacokinetic, and cost profiles. iMil therapy warrants further study in larger clinical trials. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Our experience with implantation of VentrAssist left ventricular assist device

    Directory of Open Access Journals (Sweden)

    Hiriyur Shivalingappa Jayanthkumar

    2013-01-01

    Full Text Available Perioperative anaesthetic management of the VentrAssist TM left ventricular assist device (LVAD is a challenge for anaesthesiologists because patients presenting for this operation have long-standing cardiac failure and often have associated hepatic and renal impairment, which may significantly alter the pharmacokinetics of administered drugs and render the patients coagulopathic. The VentrAssist is implanted by midline sternotomy. A brief period of cardiopulmonary bypass (CPB for apical cannulation of left ventricle is needed. The centrifugal pump, which produces non-pulsatile, continuous flow, is positioned in the left sub-diaphragmatic pocket. This LVAD is preload dependent and afterload sensitive. Transoesophageal echocardiography is an essential tool to rule out contraindications and to ensure proper inflow cannula position, and following the implantation of LVAD, to ensure right ventricular (RV function. The anaesthesiologist should be prepared to manage cardiac decompensation and acute desaturation before initiation of CPB, as well as RV failure and severe coagulopathic bleeding after CPB. Three patients had undergone implantation of VentrAssist in our hospital. This pump provides flow of 5 l/min depending on preload, afterload and pump speed. All the patients were discharged after an average of 30 days. There was no perioperative mortality.

  7. Modelling a soft composite accumulator for human mobility assist devices.

    Science.gov (United States)

    Shaheen, Robert; Doumit, Marc

    2018-04-01

    Research in the field of human mobility assist devices, aiming to reduce the metabolic cost of daily activities, is seeing the benefits of the exclusive use of accumulators to store and release energy during the gait cycle. The Pneumatic Artificial Muscle, used in a passive state, has proven to be a superior choice for these devices when compared to its alternatives, however, challenges regarding muscle pressure dissipation and a limited elongation potential have been identified. A recently developed, novel Soft Composite material has been shown to experimentally replicate the distinctive mechanical behaviour of the Pneumatic Artificial Muscle, without the need for internal pressurization. This paper presents two separate constitutive models to provide a closer insight into the behaviour of these Soft Composite accumulators. Both models were derived from methods involving finite elasticity theory and employed either a structural strain energy function of Holzapfel, Gasser, and Ogden's type or a phenomenological strain energy function of Fung's type. Both models were in good agreement with the experimental data that were collected through a modified extension-inflation test and, therefore, provide a basis for further examination as a Soft Composite design model. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Effects of an Elastic Hamstring Assistance Device During Downhill Running

    Science.gov (United States)

    Aldret, Randy L; Trahan, Brittany A; Davis, Greggory; Campbell, Brian; Bellar, David M

    2017-01-01

    Abstract The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants’ body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces. PMID:28713460

  9. Identification of tasks performed by stroke patients using a mobility assistive device

    DEFF Research Database (Denmark)

    Hester, Todd; Sherrill, Delsey M; Hamel, Mathieu

    2006-01-01

    Many stroke patients are prescribed canes or other mobility assistive devices. Once taken home, these mobility assistive devices are often abandoned or misused. A means for assessing the use of the cane in the home and community settings is required to assist clinicians in the prescription...... of these devices. In this study, we propose the use of wearable sensors to identify tasks performed by stroke patients with a mobility assistive device. Subjects performed ten tasks with a three-axis accelerometer attached to their ankle and a neural network was trained to identify the task being performed...

  10. Liberal Right Ventricular Assist Device Extracorporeal Membrane Oxygenation Support for Right Ventricular Failure after Implantable Left Ventricular Assist Device Placement.

    Science.gov (United States)

    Fischer, Quentin; Kirsch, Matthias

    2017-11-27

    Refractory right ventricular failure (RVF) after implantation of left ventricular assist device (LVAD) is a dramatic complication. The addition of right ventricular assist device (RVAD) may improve RV recovery and lead to improve outcomes. From February 2012 to September 2014, 44 patients received a HeartMate II. These patients were retrospectively compared in two groups according to early liberal implantation of an extracorporeal membrane oxygenation (ECMO) used as a RVAD established between a femoral vein and the pulmonary artery. Of the 44 patients, 22 required addition of a temporary RVAD (t-RVAD group). Patients are sicker in the t-RVAD group with significantly higher rate of preoperative extracorporeal life support (46% vs. 9%; p = 0.016) or any mechanical circulatory support (55% vs. 14%; p = 0.01), more preoperative hemofiltration (23% vs. 0%; p = 0.048), and more inotrope support by dobutamine (68.2% vs. 27.3%; p = .015). Likewise Michigan risk score was significantly higher in t-RVAD group (2.61 ± 2.2 vs. 1.0 ± 1.6 pts; p = 0.013) and INTERMACS clinical profile (2.1 ± 0.6 vs. 3.4 ± 1.3 pts; p = 0.0001). Despite severity of preimplant conditions in t-RVAD group, clinical outcomes did not differ in both groups with similar survival rate at 6 months (60.4 ± 12 vs. 71.4 ± 9.9 months; p = 0.585). Early and liberal use of temporary RVAD in patients with risk factors of RVF could improve the prognostic after LVAD implantation.

  11. Internet-Based Device-Assisted Remote Monitoring of Cardiovascular Implantable Electronic Devices

    Science.gov (United States)

    Pron, G; Ieraci, L; Kaulback, K

    2012-01-01

    Executive Summary Objective The objective of this Medical Advisory Secretariat (MAS) report was to conduct a systematic review of the available published evidence on the safety, effectiveness, and cost-effectiveness of Internet-based device-assisted remote monitoring systems (RMSs) for therapeutic cardiac implantable electronic devices (CIEDs) such as pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. The MAS evidence-based review was performed to support public financing decisions. Clinical Need: Condition and Target Population Sudden cardiac death (SCD) is a major cause of fatalities in developed countries. In the United States almost half a million people die of SCD annually, resulting in more deaths than stroke, lung cancer, breast cancer, and AIDS combined. In Canada each year more than 40,000 people die from a cardiovascular related cause; approximately half of these deaths are attributable to SCD. Most cases of SCD occur in the general population typically in those without a known history of heart disease. Most SCDs are caused by cardiac arrhythmia, an abnormal heart rhythm caused by malfunctions of the heart’s electrical system. Up to half of patients with significant heart failure (HF) also have advanced conduction abnormalities. Cardiac arrhythmias are managed by a variety of drugs, ablative procedures, and therapeutic CIEDs. The range of CIEDs includes pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. Bradycardia is the main indication for PMs and individuals at high risk for SCD are often treated by ICDs. Heart failure (HF) is also a significant health problem and is the most frequent cause of hospitalization in those over 65 years of age. Patients with moderate to severe HF may also have cardiac arrhythmias, although the cause may be related more to heart pump or haemodynamic failure. The presence of HF, however

  12. Ergonomic evaluation of a wearable assistive device for overhead work.

    Science.gov (United States)

    Rashedi, Ehsan; Kim, Sunwook; Nussbaum, Maury A; Agnew, Michael J

    2014-01-01

    Overhead work is an important risk factor for upper extremity (UE) musculoskeletal disorders. We examined the potential of a mechanical arm and an exoskeletal vest as a wearable assistive device (WADE) for overhead work. Twelve participants completed 10 minutes of simulated, intermittent overhead work, using each of three payloads (1.1, 3.4 and 8.1 kg) and with/without the WADE. Ratings of perceived discomfort (RPDs) and electromyography (EMG) were obtained for the upper arms, shoulders and low back. Using the WADE, UE RPDs decreased by ∼50% with the heavier payloads, whereas smaller (∼25%) and non-significant increases in low-back RPDs were found and were relatively independent of payload. Changes in RPDs with WADE use were consistent with physical demands indicated by EMG, though EMG-based differences in fatigue were less apparent. Participants generally preferred using the WADE, particularly with heavier payloads. These results supported the potential utility of a WADE as an intervention for overhead work.

  13. Stable and Intuitive Control of an Intelligent Assist Device.

    Science.gov (United States)

    Duchaine, V; Mayer St-Onge, Boris; Dalong Gao; Gosselin, C

    2012-01-01

    Safety and dependability are of the utmost importance for physical human-robot interaction due to the potential risks that a relatively powerful robot poses to human beings. From the control standpoint, it is possible to improve safety by guaranteeing that the robot will never exhibit any unstable behavior. However, stability is not the only concern in the design of a controller for such a robot. During human-robot interaction, the resulting cooperative motion should be truly intuitive and should not restrict in any way the human performance. For this purpose, we have designed a new variable admittance control law that guarantees the stability of the robot during constrained motion and also provides a very intuitive human interaction. The former characteristic is provided by the design of a stability observer while the latter is based on a variable admittance control scheme that uses the time derivative of the contact force to assess human intentions. The stability observer is based on a previously published stability investigation of cooperative motion which implies the knowledge of the interaction stiffness. A method to accurately estimate this stiffness online using the data coming from the encoder and from a multiaxis force sensor at the end effector is also provided. The stability and intuitivity of the control law are verified in a user study involving a cooperative drawing task with a 3 degree-of-freedom (dof) parallel robot as well as in experiments performed with a prototype of an industrial Intelligent Assist Device.

  14. Memory-assisted measurement-device-independent quantum key distribution

    International Nuclear Information System (INIS)

    Panayi, Christiana; Razavi, Mohsen; Ma, Xiongfeng; Lütkenhaus, Norbert

    2014-01-01

    A protocol with the potential of beating the existing distance records for conventional quantum key distribution (QKD) systems is proposed. It borrows ideas from quantum repeaters by using memories in the middle of the link, and that of measurement-device-independent QKD, which only requires optical source equipment at the user's end. For certain memories with short access times, our scheme allows a higher repetition rate than that of quantum repeaters with single-mode memories, thereby requiring lower coherence times. By accounting for various sources of nonideality, such as memory decoherence, dark counts, misalignment errors, and background noise, as well as timing issues with memories, we develop a mathematical framework within which we can compare QKD systems with and without memories. In particular, we show that with the state-of-the-art technology for quantum memories, it is potentially possible to devise memory-assisted QKD systems that, at certain distances of practical interest, outperform current QKD implementations. (paper)

  15. Left Ventricular Assist Device: Care On Inpatient Rehabilitation Facility.

    Science.gov (United States)

    Forrest, George; Radu, Gabriel; Rifenburg, Kathleen; Shields, Evelyn; Clift, Sarah

    2015-01-01

    Investigate the outcomes of patients admitted to an inpatient rehabilitation facility (IRF) after placement of a left ventricular assist device (LVAD). Retrospective review of records. Authors reviewed records of patients admitted to the IRF after cardiac surgery or admission to the hospital with either acute myocardial infarction, congestive heart failure, or placement of an LVAD. The study reports improvement in function, length of stay (LOS), and location of discharge. The patients in the LVAD group made as much progress in terms of improvement in function as the other groups. None of the patients in the LVAD group required transfer back to medical or surgical units. All were discharged to home. Length of stay (LOS) of the LVAD group was not significantly longer than that of the other cardiac patients. Patients who have had placement of an LVAD can be safely cared for in an IRF. This paper provides information about the indications for LVAD, the nursing care of patients with an LVAD, and the outcomes of care in an IRF. © 2014 Association of Rehabilitation Nurses.

  16. 38 CFR 17.152 - Devices to assist in overcoming the handicap of deafness.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Devices to assist in overcoming the handicap of deafness. 17.152 Section 17.152 Pensions, Bonuses, and Veterans' Relief DEPARTMENT... in overcoming the handicap of deafness. Devices for assisting in overcoming the handicap of deafness...

  17. An unknown complication of peripherally inserted central venous catheter in a patient with ventricular assist device

    Directory of Open Access Journals (Sweden)

    Parikh M

    2011-01-01

    Full Text Available We report an unknown complication of peripherally inserted central venous catheter in a patient with Ventricular Assist Device. This rare complication led to the failure of the right ventricular assist device, which could be detrimental in patients with dilated cardiomyopathy.

  18. A novel implantable electromechanical ventricular assist device - First acute animal testing

    NARCIS (Netherlands)

    Kaufmann, R; Rakhorst, G; Mihaylov, D; Elstrodt, J; Nix, C; Reul, H; Rau, G

    1997-01-01

    A novel ventricular assist device (HIA-EMLVAD-AT1, Helmholtz Institute Aachen-electromechanical Left Ventricular Assist Device-Animal Test Version 1), driven by a uniformly and unidirectionally rotating actuator and a patented hypocycloidic pusherplate displacement gear unit, was developed and

  19. In-vivo evaluation of the HIA-VAD: : a new German ventricular assist device

    NARCIS (Netherlands)

    Rakhorst, G.; Hensens, A. G.; Verkerke, G. J.; Blanksma, P. K.; Bom, V. J. J.; Elstrodt, J.; Magielse, C. P. E.; van der Meer, J; Ruel, H.

    Helmholtz Ventricular Assist Devices (VAD) are pneumatically driven polyurethane membrane pumps with various volumes. The pumps are placed paracorporeally and connected with commercially available cannulas between the left atrium and aorta (left ventricular assist device) and/or right atrium and

  20. Accuracy of different imaging modalities prior to biventricular repair ...

    African Journals Online (AJOL)

    Accuracy of different imaging modalities prior to biventricular repair in Tetralogy of Fallot. ... Internet Journal of Medical Update - EJOURNAL ... findings of different imaging modalities (e.g. echocardiography, multi-detector Computed Tomography (CT) and invasive angiocardiography) to intraoperative findings to determine ...

  1. [Experience of left ventricular assist device "Incor" as "bridge to recovery" implantation in patients with end stage congestive heart failure].

    Science.gov (United States)

    Khubulava, G G; Ivchenko, E V; Paĭvin, A A; Kravchuk, V N; Iurchenko, D L; Ivashchenko, A I; Didenko, M V; Luk'ianov, N G; Peleshok, A S; Tsygan, N V; Liubimov, A I; Naumov, A B; Shorokhov, K H; Sukharev, A E; Kniazev, E A; Porembskaia, I A

    2011-11-01

    Left ventricular assist device "Incor" ("Berlinhear", Germany) implantation experience in patient with ischemic cardiomiopathy and severe congestive heart failure is presented. Left ventricular assist device implantation was followed by coronary artery bypass grafting simultaneously. Total assist time was 211 days. Complications developed during assisting time are shown. After Left ventricular assist device explantation three chamber pacemaker was implanted as cardiac resynchronization therapy. Left ventricular end diastolic size decreased (from 78 to 70 mm), ejection fraction increased (from 19 to 35%) during assist time.

  2. Durable left ventricular assist device therapy in advanced heart failure: Patient selection and clinical outcomes

    Science.gov (United States)

    Shah, Sachin P.; Mehra, Mandeep R.

    2016-01-01

    The increasing adoption of left ventricular assist devices (LVADs) into clinical practice is related to a combination of engineering advances in pump technology and improvements in understanding the appropriate clinical use of these devices in the management of patients with advanced heart failure. This review intends to assist the clinician in identifying candidates for LVAD implantation, to examine long-term outcomes and provide an overview of the common complications related to use of these devices. PMID:27056652

  3. Ethical challenges with the left ventricular assist device as a destination therapy

    Directory of Open Access Journals (Sweden)

    Rady Mohamed Y

    2008-08-01

    Full Text Available Abstract The left ventricular assist device was originally designed to be surgically implanted as a bridge to transplantation for patients with chronic end-stage heart failure. On the basis of the REMATCH trial, the US Food and Drug Administration and the US Centers for Medicare & Medicaid Services approved permanent implantation of the left ventricular assist device as a destination therapy in Medicare beneficiaries who are not candidates for heart transplantation. The use of the left ventricular assist device as a destination therapy raises certain ethical challenges. Left ventricular assist devices can prolong the survival of average recipients compared with optimal medical management of chronic end-stage heart failure. However, the overall quality of life can be adversely affected in some recipients because of serious infections, neurologic complications, and device malfunction. Left ventricular assist devices alter end-of-life trajectories. The caregivers of recipients may experience significant burden (e.g., poor physical health, depression, anxiety, and posttraumatic stress disorder from destination therapy with left ventricular assist devices. There are also social and financial ramifications for recipients and their families. We advocate early utilization of a palliative care approach and outline prerequisite conditions so that consenting for the use of a left ventricular assist device as a destination therapy is a well informed process. These conditions include: (1 direct participation of a multidisciplinary care team, including palliative care specialists, (2 a concise plan of care for anticipated device-related complications, (3 careful surveillance and counseling for caregiver burden, (4 advance-care planning for anticipated end-of-life trajectories and timing of device deactivation, and (5 a plan to address the long-term financial burden on patients, families, and caregivers. Short-term mechanical circulatory devices (e

  4. Hemodynamic Ramp Tests in Patients With Left Ventricular Assist Devices.

    Science.gov (United States)

    Uriel, Nir; Sayer, Gabriel; Addetia, Karima; Fedson, Savitri; Kim, Gene H; Rodgers, Daniel; Kruse, Eric; Collins, Keith; Adatya, Sirtaz; Sarswat, Nitasha; Jorde, Ulrich P; Juricek, Colleen; Ota, Takeyoshi; Jeevanandam, Valluvan; Burkhoff, Daniel; Lang, Roberto M

    2016-03-01

    This study tested whether combined invasive hemodynamic and echocardiographic ramp tests can help optimize patient management. Guidelines for optimizing speed and medications in continuous flow ventricular assist device (cfLVAD) patients are mainly based on expert opinion. Thirty-five cfLVAD patients (21 HeartMate II [Thoratec, Pleasanton, California] and 14 HVAD [HeartWare International, Framingham, Massachusetts]) underwent ramp tests with right heart catheterization (including central venous pressure [CVP], pulmonary artery pressure, pulmonary capillary wedge pressure [PCWP], and blood pressure) and echocardiography. Data were recorded at up to 9 speed settings. Speed changes were in steps of 400 revolutions per minute (RPM) for HeartMate II (8,000 to 12,000 RPM) and 100 RPM for HVAD (2,300 to 3,200 RPM) patients. Only 42.9% of patients had normal CVPs and PCWPs at their original RPM settings. Going from lowest to highest speeds, cardiac output improved by 0.16 ± 0.19 l/min/step (total change 1.28 ± 1.41 l/min) and PCWP decreased by 1.23 ± 0.85 mm Hg/step (total change 9.9 ± 6.5 mm Hg). CVP and systolic blood pressure did not change significantly with RPM. RPM were adjusted based on test results to achieve CVPs and PCWPs as close to normal limits as possible, which was feasible in 56% of patients. For the remainder, results indicated which type of medical management should be pursued. Use of combined hemodynamic and echocardiographic ramp tests in patients provides objective means of optimizing RPM, and has the potential to guide medical management. It remains to be tested whether this strategy has a beneficial impact on quality of life or clinical outcomes. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  5. Device-specific evaluation of intraventricular left ventricular assist device position by quantitative coaxiality analysis.

    Science.gov (United States)

    Anselmi, Amedeo; Collin, Sophie; Haigron, Pascal; Verhoye, Jean-Philippe; Flecher, Erwan

    2017-06-01

    Patient-specific anatomy may influence the final intraventricular positioning of inflow cannula in left ventricular assist device (LVAD) recipients. An association exists between such positioning and clinical outcomes (specifically, orientation toward the interventricular septum has negative prognostic implications). Alternative commercially available LVADs are characterized by markedly different design, with potential consequences on intrathoracic fitting among individual patients. A cohort of 13 LVAD recipients (either HeartMate II-group A or Jarvik 2000 Flowmaker-group B) was evaluated. On postoperative computed tomography scans, we reconstructed the implanted LVAD (semiautomatic segmentation), defined the target mitral orifice (3D Slicer software), and built a coordinate system to quantify the coaxiality of the cannula with the mitral valve axis (angles φ and θ, expressed as percentage variation from the ideal value φ = θ = 0°). Group A presented significantly greater average percentage variation of the φ angle (significantly greater orientation of the intraventricular cannula toward the interventricular septum; 33.2% ± 32.1% versus 1.9% ± 0.9%, P = 0.001). Group A presented significantly greater average percentage variation of the θ angle (52.7% ± 23.6% versus 14.5% ± 6.3%, P = 0.013). The device assessed in group B showed in the present series better average coaxiality with the mitral orifice. Such finding is related with its design (total intraventricular placement) and interaction with thoracic structures. The present method is being integrated in the development of LVAD virtual implantation tools and may help physicians in patient-specific selection among alternative devices. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Simulating ideal assistive devices to reduce the metabolic cost of walking with heavy loads.

    Directory of Open Access Journals (Sweden)

    Christopher L Dembia

    Full Text Available Wearable robotic devices can restore and enhance mobility. There is growing interest in designing devices that reduce the metabolic cost of walking; however, designers lack guidelines for which joints to assist and when to provide the assistance. To help address this problem, we used musculoskeletal simulation to predict how hypothetical devices affect muscle activity and metabolic cost when walking with heavy loads. We explored 7 massless devices, each providing unrestricted torque at one degree of freedom in one direction (hip abduction, hip flexion, hip extension, knee flexion, knee extension, ankle plantarflexion, or ankle dorsiflexion. We used the Computed Muscle Control algorithm in OpenSim to find device torque profiles that minimized the sum of squared muscle activations while tracking measured kinematics of loaded walking without assistance. We then examined the metabolic savings provided by each device, the corresponding device torque profiles, and the resulting changes in muscle activity. We found that the hip flexion, knee flexion, and hip abduction devices provided greater metabolic savings than the ankle plantarflexion device. The hip abduction device had the greatest ratio of metabolic savings to peak instantaneous positive device power, suggesting that frontal-plane hip assistance may be an efficient way to reduce metabolic cost. Overall, the device torque profiles generally differed from the corresponding net joint moment generated by muscles without assistance, and occasionally exceeded the net joint moment to reduce muscle activity at other degrees of freedom. Many devices affected the activity of muscles elsewhere in the limb; for example, the hip flexion device affected muscles that span the ankle joint. Our results may help experimentalists decide which joint motions to target when building devices and can provide intuition for how devices may interact with the musculoskeletal system. The simulations are freely available

  7. Considering Material Culture in Assessing Assistive Devices: “Breaking up the Rhythm”

    Directory of Open Access Journals (Sweden)

    Sharon Anderson

    2016-04-01

    Full Text Available This paper reports on a project that looked at the meaning stroke survivors assigned to assistive devices. Material culture theory served as a framework to help stroke survivors explicitly consider [dis]ability as a discursive object with a socially constructed meaning that influenced how they thought about themselves with impairment. Material culture theory informed the design (taking and talking to their peers about photos of anything that assisted and analysis of the meaning of the assistive devices project. In our analysis of the narratives, survivors assigned three types of meanings to the assistive devices: markers of progress, symbolic objects of disability, and the possibility of independent participation. Notably, the meaning of assistive devices as progress, [dis]ability, and [poss]ability was equally evident as participants talked about mobility, everyday activities, and services. We discuss how considering [dis]ability as a discursive object in the situation might have enabled stroke survivors to participate.

  8. Simulating Ideal Assistive Devices to Reduce the Metabolic Cost of Running.

    Directory of Open Access Journals (Sweden)

    Thomas K Uchida

    Full Text Available Tools have been used for millions of years to augment the capabilities of the human body, allowing us to accomplish tasks that would otherwise be difficult or impossible. Powered exoskeletons and other assistive devices are sophisticated modern tools that have restored bipedal locomotion in individuals with paraplegia and have endowed unimpaired individuals with superhuman strength. Despite these successes, designing assistive devices that reduce energy consumption during running remains a substantial challenge, in part because these devices disrupt the dynamics of a complex, finely tuned biological system. Furthermore, designers have hitherto relied primarily on experiments, which cannot report muscle-level energy consumption and are fraught with practical challenges. In this study, we use OpenSim to generate muscle-driven simulations of 10 human subjects running at 2 and 5 m/s. We then add ideal, massless assistive devices to our simulations and examine the predicted changes in muscle recruitment patterns and metabolic power consumption. Our simulations suggest that an assistive device should not necessarily apply the net joint moment generated by muscles during unassisted running, and an assistive device can reduce the activity of muscles that do not cross the assisted joint. Our results corroborate and suggest biomechanical explanations for similar effects observed by experimentalists, and can be used to form hypotheses for future experimental studies. The models, simulations, and software used in this study are freely available at simtk.org and can provide insight into assistive device design that complements experimental approaches.

  9. Left ventricular assist device (lvad design features: literature review

    Directory of Open Access Journals (Sweden)

    Yu. V. Bogdanova

    2014-01-01

    Full Text Available More than 8 million people in our country suffer from heart failure. About one million of these people die each year [1]. The problem of ventricular assist device creating - a mechanical device used for partial or complete replacement of heart function - is investigated for a long time (according to [2] just in our country since the 1970s. Today plenty of encouraging results are received. There is a number of VAD models which are successfully applied to patients with heart failure. After implantation, patients conduct a way of life that is normal in many respects: they are in the family, often they have an opportunity to work in their former specialty. Some of them live with the device about 8 years [3].According to [4] for 2010 the estimated total number of long-term devices implanted in the United States per year is over 1,700 (the population of the U.S. is 305 million, compared with over 430 per year in Europe (the population of Europe is 731 million. Unfortunately, people who need a heart transplant are much more.The principle of VAD is that being connected to the left ventricle with one cannula and to the ascending aorta with the other cannula the pump fully or partially replaces the function of the natural heart. This scheme allows the use of VAD in two ways: as a "bridge to transplantation" when the device is used temporarily until the donor heart is found, and a "bridge to recovery", when through the use of VAD the function of the heart muscle is recovered.VAD system can be divided into three subsystems: blood pump, power supply system and control system (Fig. 1.Each subsystem can be the subject of separate study. Special role in the development of VAD plays medical side of the issue. Successful research and development require interaction with qualified professionals in this field. The development of VAD is a multidisciplinary problem which demands fulfilment of a number of requirements.One of the most active programs in implantation of

  10. Institutional Cost Comparison Between Heart Transplants and Left Ventricular Assist Device Implantations.

    Science.gov (United States)

    Chimanji, Neeraj; Kilic, Arman; Hasan, Ayesha; Higgins, Robert S D; Whitson, Bryan A; Kilic, Ahmet

    2016-12-01

    Increased numbers of end-stage heart failure patients and improved technology have led to increased use of left ventricular assist devices as a viable alternative to heart transplants. Given the current economic climate, we compared costs of heart transplant versus device placement. Medical records of patients who received heart transplants or left ventricular assist devices were cross-referenced with institutional financial data. The device cohort was limited to those receiving durable (not temporary) devices. Index admission, 1-year readmission, and overall 1-year charges were compared using standard statistical methods. Of 184 identified patients with end-stage heart failure surgical therapy, 121 received left ventricular assist devices, 43 had heart transplants, and 20 received left ventricular assist devices as bridge to heart transplant; these latter patients were excluded from our analyses. At index admission, mean charges were $863 433 ± $398 427 for device patients and $725 877 ± $488 685 for transplant patients (P = .05). One-year mean readmission rates were similar (4.65/transplant patient and 4.53/device patient; P = .94), with corresponding 1-year survival rates of 87.8% and 78.0% (P = .04). Total readmission charges during year 1 were $169 732 ± $242 366 for device patients and $201 682 ± $297 565 for transplant patients (P = .08), with corresponding overall charges at 1 year of $1 029 732 ± $450 498 and $927 559 ± $562 404 (P = .49). During the first year, heart transplant and left ventricular assist device placement have similar costs. Initial index admission costs seem to favor heart transplant, with device pump costs accounting for some of the difference. From a 1-year survival perspective, heart transplant may be more effective; however, with lack of suitable donors, left ventricular assist devices are valuable in the armamentarium of advanced heart failure surgical options.

  11. Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison.

    Science.gov (United States)

    Avery, Ryan; Day, Kevin; Jokerst, Clinton; Kazui, Toshinobu; Krupinski, Elizabeth; Khalpey, Zain

    2017-10-10

    FPRNA was 32.6% (9 - 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 - 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 - 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 - 0.72) and for FAC of 0.64 (95% of 0.21 - 1.00). Heart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

  12. Analysis of Contemporary Methods for Designing Rotary Type Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    E. P. Banin

    2015-01-01

    Full Text Available The research object is inlet apparatus of ventricular assist device, namely inlet cannula and straightener.The purpose of the study is to reveal features of blood flow in inlet apparatus of ventricular assist device. The mathematical modeling is carried out by computational fluid dynamics analysis in a stationary setting.The first part of study concerns the analysis of existing approaches to the numerical and experimental studies in designing the ventricular assist devices of rotary type. It reveals the features of each approach for their further application in practice. The article presents an original design of developed hydraulic test bench to verify the results of mathematical modeling. Analysis of foreign authors’ studies showed that there is no enough attention paid to design of the adjacent pump assemblies of ventricular assist device. The second part of study considers direct mathematical modeling of input apparatus of ventricular assist device. The study examined straightener with three or four blades. Mathematical modeling has revealed the presence of potentially dangerous stagnation zones and essential asymmetry of the outlet flow from the input unit. The found features must be taken in consideration in designing the ventricular assist device pumps. In the future we plan to use obtained data to create a parametric model of the rotor and the diffuser considering the abovementioned features.

  13. Universal Open Power, Communications, and Control for Assistive Devices

    Science.gov (United States)

    2017-10-01

    with electronic damping control LEGS Data Arbitrator • WiFi, DART, BLE , I2C, SPI, UART, PWM • Device hardware control • Cloud data streaming...PWM • Device hardware control • Cloud data streaming Integrated Odyssey K3 • Open-access ankle with electronic damping control LEGS...The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the

  14. Impact of interface charge on the electrostatics of field-plate assisted RESURF devices

    NARCIS (Netherlands)

    Boksteen, B.K.; Ferrara, A.; Heringa, A.; Steeneken, P.G.; Hueting, Raymond Josephus Engelbart

    2014-01-01

    A systematic study on the effects of arbitrary parasitic charge profiles, such as trapped or fixed charge, on the 2-D potential distribution in the drain extension of reverse-biased field-plate-assisted reduced surface field (RESURF) devices is presented. Using TCAD device simulations and analytical

  15. On the degradation of field-plate assisted RESURF power devices

    NARCIS (Netherlands)

    Boksteen, B.K.; Dhar, S.; Ferrara, A.; Heringa, A.; Hueting, Raymond Josephus Engelbart; Koops, G.E.J.; Salm, Cora; Schmitz, Jurriaan

    2012-01-01

    Hot-carrier degradation phenomena in field-plate assisted reduced surface field (RESURF) devices caused by high voltage off- and on-state stressing have been investigated. The device I-V characteristics are analyzed and modeled in detail. It is shown that via noninvasive low-voltage leakage

  16. Computation of blood flow in a diaphragm-type ventricular assist device

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, M.G.; Tavoularis, S. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada)]. E-mail: mdoyle@eng.uottawa,ca; Bourgault, Y. [Univ. of Ottawa, Dept. of Mechanical Engineering and Dept. of Mathematics and Statistics, Ottawa, Ontario (Canada)

    2004-07-01

    The finite element method was used to simulate blood flow in an idealized diaphragm-type ventricular assist device, taking into consideration fluid-structure interaction effects. The results of this pilot study have been partly validated versus available experimental and computational results. It is concluded that this is a feasible approach for the modelling of similar devices for design and optimization purposes. (author)

  17. The use of Computer Assisted Language Learning (CALL) Devices ...

    African Journals Online (AJOL)

    Computer-Assisted Language Learning (CALL) is a relatively new and rapidly evolving academic field that explores the role of information and communication technologies in language learning and teaching. It has rapidly developed over the last forty years. This development can be categorized into three distinct phases: ...

  18. Design and Control of a Wearable Stewart Platform-Type Ankle-Foot Assistive Device

    Directory of Open Access Journals (Sweden)

    Hiroshi Takemura

    2012-11-01

    Full Text Available The design and control of an active ankle-foot rehabilitation orthotic system that was designed as a wearable and portable rehabilitation and walking assistive tool is presented. This device can measure and assist the six degree of freedoms (DOFs movement of the human ankle joint by using a Stewart platform mechanism, which can adapt to the displacement of the rotation axis during the movement of a human foot. The estimation method of an instantaneous rotation axis of ankle-foot motion is also proposed. In this paper, the motion measurement and motion control performance of the developed assistive device is evaluated. Static and dynamic motion measurement and motion reproduction performance verification experiments are conducted. The experimental results showed that the developed assistive device is enough for measuring and controlling the human ankle-foot motion.

  19. User assistance for multitasking with interruptions on a mobile device

    NARCIS (Netherlands)

    Nagata, S.F.

    2006-01-01

    Issues users have with use of the web on a mobile device can be attributed to difficulties with the mobile interface. A major challenge that we address is improving the user experience for handling of interruptions and multitasking when using the web in a mobile context. The usability issues with a

  20. User Assistance for Multitasking with Interruptions on a Mobile Device

    NARCIS (Netherlands)

    Nagata, S.F.

    2006-01-01

    Issues users have with use of the web on a mobile device can be attributed to difficulties with the mobile interface. A major challenge that we address is improving the user experience for handling of interruptions and multitasking when using the web in a mobile context. The usability issues with a

  1. Ethical framework of assistive devices: review and reflection.

    Science.gov (United States)

    Mansouri, Nazanin; Goher, Khaled; Hosseini, Seyed Ebrahim

    2017-01-01

    The population of ageing is growing significantly over the world, and there is an emerging demand for better healthcare services and more care centres. Innovations of Information and Communication Technology has resulted in development of various types of assistive robots to fulfil elderly's needs and independency, whilst carrying out daily routine tasks. This makes it vital to have a clear understanding of elderly's needs and expectations from assistive robots. This paper addresses current ethical issues to understand elderly's prime needs. Also, we consider other general ethics with the purpose of applying these theories to form a proper ethics framework. In the ethics framework, the ethical concerns of senior citizens will be prioritized to satisfy elderly's needs and also to diminish related expenses to healthcare services.

  2. VENTRICLE ASSIST DEVICE: PAST, PRESENT, AND FUTURE NONPULSATILE PUMPS

    Directory of Open Access Journals (Sweden)

    G. Р. Itkin

    2009-01-01

    Full Text Available The article briefly describes the history of the non-pulsating type blood pumps for ventricular assist circulation and heart-lung machine. Disclosed the main advantages of these pumps before pulsating type, especially for implantable systems development. However, disadvantages of these pumps and the directions of minimize or eliminate ones have shown. Specific examples of our implantable centrifugal and axial pump developments are presented. Declare the ways to further improve the pumps. 

  3. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices

    Science.gov (United States)

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie

    2016-09-01

    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes’ (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.

  4. Early Assistance With Left Ventricular Assist Device Limits Left Ventricular Remodeling After Acute Myocardial Infarction in a Swine Model.

    Science.gov (United States)

    Sun, Xiaotian; Li, Jun; Zhao, Weipeng; Lu, Shuyang; Guo, Changfa; Lai, Hao; Wang, Chunsheng

    2016-03-01

    Although left ventricular assist devices (LVADs) have been commonly used for patients with cardiogenic shock after acute myocardial infarction (AMI), their effects on post-AMI prognosis remain to be elucidated. In this study, we aimed to explore the effects of an LVAD on left ventricular (LV) remodeling and function at the postinfarction stage in a swine model. AMI was induced by ligation of the circumflex artery or its branches for 120 min, followed by 120 min of reperfusion. In the assist group (n = 6), LVAD was initiated at 90 min after ischemia and was maintained for support until 120 min after reperfusion, whereas the control group (n = 6) received no support. LV pressure, volume, wall stress, and stroke work were all decreased by LVAD assistance at the ischemia and reperfusion stages, and blood pressure and cardiac output were maintained. All swine were studied 1 month after the procedure, and those in the assist group showed less increased end-diastolic volumes (assist vs. 57.9 ± 6.6 vs. 79.0 ± 6.7 mL, P = 0.032) and sphericity (assist vs. 1.33 ± 0.16 vs. 1.51 ± 0.12, P = 0.01), as well as improved ejection fractions (assist vs. 59.0 ± 7.8 vs. 42.3 ± 6.0%, P = 0.002). Furthermore, despite a presence of a similar initial ischemic area, the percent of infarcted myocardium was reduced by 49.9% in the assist group (assist vs. 18.1 ± 4.8 vs. 35.3 ± 6.2%, P assistance with an LVAD in AMI limited LV remodeling, preserved postinfarction systolic function, and improved the prognosis. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  5. Modelling Framework and Assistive Device for Peripheral Intravenous Injections

    Science.gov (United States)

    Kam, Kin F.; Robinson, Martin P.; Gilbert, Mathew A.; Pelah, Adar

    2016-02-01

    Intravenous access for blood sampling or drug administration that requires peripheral venepuncture is perhaps the most common invasive procedure practiced in hospitals, clinics and general practice surgeries.We describe an idealised mathematical framework for modelling the dynamics of the peripheral venepuncture process. Basic assumptions of the model are confirmed through motion analysis of needle trajectories during venepuncture, taken from video recordings of a skilled practitioner injecting into a practice kit. The framework is also applied to the design and construction of a proposed device for accurate needle guidance during venepuncture administration, assessed as consistent and repeatable in application and does not lead to over puncture. The study provides insights into the ubiquitous peripheral venepuncture process and may contribute to applications in training and in the design of new devices, including for use in robotic automation.

  6. A novel curve fitting method for AV optimisation of biventricular pacemakers.

    Science.gov (United States)

    Dehbi, Hakim-Moulay; Jones, Siana; Sohaib, S M Afzal; Finegold, Judith A; Siggers, Jennifer H; Stegemann, Berthold; Whinnett, Zachary I; Francis, Darrel P

    2015-09-01

    In this study, we designed and tested a new algorithm, which we call the 'restricted parabola', to identify the optimum atrioventricular (AV) delay in patients with biventricular pacemakers. This algorithm automatically restricts the hemodynamic data used for curve fitting to the parabolic zone in order to avoid inadvertently selecting an AV optimum that is too long.We used R, a programming language and software environment for statistical computing, to create an algorithm which applies multiple different cut-offs to partition curve fitting of a dataset into a parabolic and a plateau region and then selects the best cut-off using a least squares method. In 82 patients, AV delay was adjusted and beat-to-beat systolic blood pressure (SBP) was measured non-invasively using our multiple-repetition protocol. The novel algorithm was compared to fitting a parabola across the whole dataset to identify how many patients had a plateau region, and whether a higher hemodynamic response was achieved with one method.In 9/82 patients, the restricted parabola algorithm detected that the pattern was not parabolic at longer AV delays. For these patients, the optimal AV delay predicted by the restricted parabola algorithm increased SBP by 1.36 mmHg above that predicted by the conventional parabolic algorithm (95% confidence interval: 0.65 to 2.07 mmHg, p-value = 0.002).AV optima selected using our novel restricted parabola algorithm give a greater improvement in acute hemodynamics than fitting a parabola across all tested AV delays. Such an algorithm may assist the development of automated methods for biventricular pacemaker optimisation.

  7. Development of Hand Grip Assistive Device Control System for Old People through Electromyography (EMG Signal Acquisitions

    Directory of Open Access Journals (Sweden)

    Khamis Herman

    2017-01-01

    Full Text Available The hand grip assistive device is a glove to assist old people who suffer from hand weakness in their daily life activities. The device earlier control system only use simple on and off switch. This required old people to use both hand to activate the device. The new control system of the hand grip assistive device was developed to allow single hand operation for old people. New control system take advantages of electromyography (EMG and flex sensor which was implemented to the device. It was programmed into active and semi-active mode operation. EMG sensors were placed on the forearm to capture EMG signal of Flexor Digitorum Profundus muscle to activate the device. Flex sensor was used to indicate the finger position and placed on top of the finger. The signal from both sensors then used to control the device. The new control system allowed single hand operation and designed to prevent user from over depended on the device by activating it through moving their fingers.

  8. 14 CFR 382.121 - What mobility aids and other assistive devices may passengers with a disability bring into the...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false What mobility aids and other assistive... REGULATIONS NONDISCRIMINATION ON THE BASIS OF DISABILITY IN AIR TRAVEL Stowage of Wheelchairs, Other Mobility Aids, and Other Assistive Devices § 382.121 What mobility aids and other assistive devices may...

  9. Beneficial effects of biventricular pacing in a patient with hypertrophic cardiomyopathy and intraventricular conduction delay

    OpenAIRE

    Rinaldi, C A; Bucknall, C A; Gill, J S

    2002-01-01

    The beneficial use of biventricular pacing is reported in a patient with hypertrophic cardiomyopathy and intraventricular conduction delay. This resulted in improvements in symptomatic status and exercise tolerance that may be related to cardiac resynchronisation. The improvement in symptoms by biventricular pacing in a patient with hypertrophic cardiomyopathy and intraventricular conduction delay is previously undocumented and requires further investigation.

  10. A Passively-Suspended Tesla Pump Left Ventricular Assist Device

    Science.gov (United States)

    Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

  11. Improving hemodynamics of cardiovascular system under a novel intraventricular assist device support via modeling and simulations.

    Science.gov (United States)

    Zhu, Shidong; Luo, Lin; Yang, Bibo; Li, Xinghui; Wang, Xiaohao

    2017-12-01

    Ventricular assist devices (LVADs) are increasingly recognized for supporting blood circulation in heart failure patients who are non-transplant eligible. Because of its volume, the traditional pulsatile device is not easy to implant intracorporeally. Continuous flow LVADs (CF-LVADs) reduce arterial pulsatility and only offer continuous flow, which is different from physiological flow, and may cause long-term complications in the cardiovascular system. The aim of this study was to design a new pulsatile assist device that overcomes this disadvantage, and to test this device in the cardiovascular system. Firstly, the input and output characteristics of the new device were tested in a simple cardiovascular mock system. A detailed mathematical model was established by fitting the experimental data. Secondly, the model was tested in four pathological cases, and was simulated and coupled with a fifth-order cardiovascular system and a new device model using Matlab software. Using assistance of the new device, we demonstrated that the left ventricle pressure, aortic pressure, and aortic flow of heart failure patients improved to the levels of a healthy individual. Especially, in state IV level heart failure patients, the systolic blood pressure increased from 81.34 mmHg to 132.1 mmHg, whereas the diastolic blood pressure increased from 54.28 mmHg to 78.7 mmHg. Cardiac output increased from 3.21 L/min to 5.16 L/min. The newly-developed assist device not only provided a physiological flow that was similar to healthy individuals, but also effectively improved the ability of the pathological ventricular volume. Finally, the effects of the new device on other hemodynamic parameters are discussed.

  12. Sensor-Based Assistive Devices for Visually-Impaired People: Current Status, Challenges, and Future Directions.

    Science.gov (United States)

    Elmannai, Wafa; Elleithy, Khaled

    2017-03-10

    The World Health Organization (WHO) reported that there are 285 million visuallyimpaired people worldwide. Among these individuals, there are 39 million who are totally blind. There have been several systems designed to support visually-impaired people and to improve the quality of their lives. Unfortunately, most of these systems are limited in their capabilities. In this paper, we present a comparative survey of the wearable and portable assistive devices for visuallyimpaired people in order to show the progress in assistive technology for this group of people. Thus, the contribution of this literature survey is to discuss in detail the most significant devices that are presented in the literature to assist this population and highlight the improvements, advantages, disadvantages, and accuracy. Our aim is to address and present most of the issues of these systems to pave the way for other researchers to design devices that ensure safety and independent mobility to visually-impaired people.

  13. Sensor-Based Assistive Devices for Visually-Impaired People: Current Status, Challenges, and Future Directions

    Directory of Open Access Journals (Sweden)

    Wafa Elmannai

    2017-03-01

    Full Text Available The World Health Organization (WHO reported that there are 285 million visuallyimpaired people worldwide. Among these individuals, there are 39 million who are totally blind. There have been several systems designed to support visually-impaired people and to improve the quality of their lives. Unfortunately, most of these systems are limited in their capabilities. In this paper, we present a comparative survey of the wearable and portable assistive devices for visuallyimpaired people in order to show the progress in assistive technology for this group of people. Thus, the contribution of this literature survey is to discuss in detail the most significant devices that are presented in the literature to assist this population and highlight the improvements, advantages, disadvantages, and accuracy. Our aim is to address and present most of the issues of these systems to pave the way for other researchers to design devices that ensure safety and independent mobility to visually-impaired people.

  14. Sensor-Based Assistive Devices for Visually-Impaired People: Current Status, Challenges, and Future Directions

    Science.gov (United States)

    Elmannai, Wafa; Elleithy, Khaled

    2017-01-01

    The World Health Organization (WHO) reported that there are 285 million visually-impaired people worldwide. Among these individuals, there are 39 million who are totally blind. There have been several systems designed to support visually-impaired people and to improve the quality of their lives. Unfortunately, most of these systems are limited in their capabilities. In this paper, we present a comparative survey of the wearable and portable assistive devices for visually-impaired people in order to show the progress in assistive technology for this group of people. Thus, the contribution of this literature survey is to discuss in detail the most significant devices that are presented in the literature to assist this population and highlight the improvements, advantages, disadvantages, and accuracy. Our aim is to address and present most of the issues of these systems to pave the way for other researchers to design devices that ensure safety and independent mobility to visually-impaired people. PMID:28287451

  15. Embedded Control System for Smart Walking Assistance Device.

    Science.gov (United States)

    Bosnak, Matevz; Skrjanc, Igor

    2017-03-01

    This paper presents the design and implementation of a unique control system for a smart hoist, a therapeutic device that is used in rehabilitation of walking. The control system features a unique human-machine interface that allows the human to intuitively control the system just by moving or rotating its body. The paper contains an overview of the complete system, including the design and implementation of custom sensors, dc servo motor controllers, communication interfaces and embedded-system based central control system. The prototype of the complete system was tested by conducting a 6-runs experiment on 11 subjects and results are showing that the proposed control system interface is indeed intuitive and simple to adopt by the user.

  16. Implantable physiologic controller for left ventricular assist devices with telemetry capability.

    Science.gov (United States)

    Asgari, Siavash S; Bonde, Pramod

    2014-01-01

    Rotary type left ventricular assist devices have mitigated the problem of durability associated with earlier pulsatile pumps and demonstrated improved survival. However, the compromise is the loss of pulsatility due to continuous flow and retained percutaneous driveline leading to increased mortality and morbidity. Lack of pulsatility is implicated in increased gastrointestinal bleeding, aortic incompetence, and diastolic hypertension. We present a novel, wirelessly powered, ultra-compact, implantable physiologic controller capable of running a left ventricular assist device in a pulsatile mode with wireless power delivery. The schematic of our system was laid out on a circuit board to wirelessly receive power and run a left ventricular assist device with required safety and backup measures. We have embedded an antenna and wireless network for telemetry. Multiple signal processing steps and controlling algorithm were incorporated. The controller was tested in in vitro and in vivo experiments. The controller drove left ventricular assist devices continuously for 2 weeks in an in vitro setup and in vivo without any failure. Our controller is more power efficient than the current Food and Drug Administration-approved left ventricular assist device controllers. When used with electrocardiography synchronization, the controller allowed on-demand customization of operation with instantaneous flow and revolutions per minute changes, resulting in a pulsatile flow with adjustable pulse pressure. Our test results prove the system to be remarkably safe, accurate, and efficient. The unique combination of wireless powering and small footprint makes this system an ideal totally implantable physiologic left ventricular assist device system. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  17. Echocardiographic outflow pump ramp test in centrifugal-flow left ventricular assist device.

    Science.gov (United States)

    Iacovoni, Attilio; Vittori, Claudia; Fontana, Alessandra; Carobbio, Alessandra; Fino, Carlo; D'Elia, Emilia; Terzi, Amedeo; Senni, Michele

    2017-04-18

    This study sought to develop a novel echocardiogram outflow ramp test to detect device malfunctions in centrifugal-flow left ventricular assist devices (LVADs). This new ramp pump test is based on the direct analyses of systolic and diastolic ratio (S/D) Doppler velocity in the outflow cannula in the HeartWare LVAD during progressive increases in speed. The results showed that in patients with normal pump function, the Doppler velocity S/D ratio gradually decreased during LVAD speed increases. This test is easily performed and seems promising to detect normal pump function in patients assisted by a centrifugal flow LVAD.

  18. Rapid progression of carotid artery atherosclerosis and stenosis in a patient with a ventricular assist device

    Directory of Open Access Journals (Sweden)

    James A. Saltsman, III, MD, MPH

    2016-06-01

    Full Text Available This case describes the management of cerebrovascular disease in a patient with a left ventricular assist device (LVAD who was awaiting cardiac transplantation. It demonstrates several unique features in managing vascular disease in patients with cardiac assist devices. First, we detail the difficulties in using duplex ultrasound to assess patients with altered hemodynamic physiology. Second, we report an instance of rapid progression of known carotid stenosis in a patient with a recently placed LVAD. This case suggests that patients with any degree of carotid stenosis before LVAD placement should be monitored closely for progression after the LVAD is placed.

  19. Non-Exposure, Device-Assisted Endoscopic Full-thickness Resection.

    Science.gov (United States)

    Bauder, Markus; Schmidt, Arthur; Caca, Karel

    2016-04-01

    Recent developments have expanded the frontier of interventional endoscopy toward more extended resections following surgical principles. This article presents two new device-assisted techniques for endoscopic full-thickness resection in the upper and lower gastrointestinal tract. Both methods are nonexposure techniques avoiding exposure of gastrointestinal contents to the peritoneal cavity by a "close first-cut later" principle. The full-thickness resection device is a novel over-the-scope device designed for clip-assisted full-thickness resection of colorectal lesions. Endoscopic full-thickness resection of gastric subepithelial tumors can be performed after placing transmural sutures underneath the tumor with a suturing device originally designed for endoscopic antireflux therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. The embodiment of assistive devices-from wheelchair to exoskeleton

    Science.gov (United States)

    Pazzaglia, Mariella; Molinari, Marco

    2016-03-01

    Spinal cord injuries (SCIs) place a heavy burden on the healthcare system and have a high personal impact and marked socio-economic consequences. Clinically, no absolute cure for these conditions exists. However, in recent years, there has been an increased focus on new robotic technologies that can change the frame we think about the prognosis for recovery and for treating some functions of the body affected after SCIs. This review has two goals. The first is to assess the possibility of the embodiment of functional assistive tools after traumatic disruption of the neural pathways between the brain and the body. To this end, we will examine how altered sensorimotor information modulates the sense of the body in SCI. The second goal is to map the phenomenological experience of using external tools that typically extend the potential of the body physically impaired by SCI. More specifically, we will focus on the difference between the perception of one's physically augmented and non-augmented affected body based on observable and measurable behaviors. We discuss potential clinical benefits of enhanced embodiment of the external objects by way of multisensory interventions. This review argues that the future evolution of human robotic technologies will require adopting an embodied approach, taking advantage of brain plasticity to allow bionic limbs to be mapped within the neural circuits of physically impaired individuals.

  1. The embodiment of assistive devices-from wheelchair to exoskeleton.

    Science.gov (United States)

    Pazzaglia, Mariella; Molinari, Marco

    2016-03-01

    Spinal cord injuries (SCIs) place a heavy burden on the healthcare system and have a high personal impact and marked socio-economic consequences. Clinically, no absolute cure for these conditions exists. However, in recent years, there has been an increased focus on new robotic technologies that can change the frame we think about the prognosis for recovery and for treating some functions of the body affected after SCIs. This review has two goals. The first is to assess the possibility of the embodiment of functional assistive tools after traumatic disruption of the neural pathways between the brain and the body. To this end, we will examine how altered sensorimotor information modulates the sense of the body in SCI. The second goal is to map the phenomenological experience of using external tools that typically extend the potential of the body physically impaired by SCI. More specifically, we will focus on the difference between the perception of one's physically augmented and non-augmented affected body based on observable and measurable behaviors. We discuss potential clinical benefits of enhanced embodiment of the external objects by way of multisensory interventions. This review argues that the future evolution of human robotic technologies will require adopting an embodied approach, taking advantage of brain plasticity to allow bionic limbs to be mapped within the neural circuits of physically impaired individuals. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. A Numerical Analysis of Phononic-Assisted Control of Ultrasound Waves in Acoustofluidic Device

    DEFF Research Database (Denmark)

    Moiseyenko, Rayisa; Bruus, Henrik

    2015-01-01

    and streaming has received much attention, since it relies solely on mechanical properties such as particle size and contrast in density and compressibility. We present a theoretical study of phononic-assisted control of ultrasound waves in acoustofluidic devices. We propose the use of phononic crystal...... can be made configurable, by embedding the diffractors, all working at the same excitation frequency but with different resulting diffraction patterns, in exchangeable membranes on top of the device....

  3. The Jarvik 2000 left ventricular assist device as a bridge to transplantation: Japanese Registry for Mechanically Assisted Circulatory Support.

    Science.gov (United States)

    Kohno, Hiroki; Matsumiya, Goro; Sawa, Yoshiki; Ono, Minoru; Saiki, Yoshikatsu; Shiose, Akira; Yamazaki, Kenji; Matsui, Yoshiro; Niinami, Hiroshi; Matsuda, Hikaru; Kitamura, Soichiro; Nakatani, Takeshi; Kyo, Shunei

    2018-01-01

    The Jarvik 2000 ventricular assist device features a miniaturized intraventricular pump and an intermittent low-speed function that facilitates aortic valve opening. Despite its long history, little is known about the Jarvik device with regard to post-implantation outcomes. Prospectively collected data from 13 participating hospitals were extracted from the Japanese Registry for Mechanically Assisted Circulatory Support database to analyze mortality, morbidity and de-novo aortic regurgitation. Data on 83 patients who underwent implantation of the Jarvik 2000 were reviewed. Median support duration was 191 (maximum 758) days. All recipients underwent implantation as a bridge to transplantation. Overall survival proportions at 1 and 2 years were 85.0% and 79.3%, respectively. Nine patients were in INTERMACS Level 1, and 28 patients were on mechanical circulatory support at the time of implantation. Causes of death included stroke, infection and device malfunction. Three patients had their device removed: 2 at the time of heart transplantation and 1 after recovery of the left ventricle. Common adverse events included major bleeding (27.7%), new infection (31.3%), stroke (20.5%) and device malfunction (20.5%). De-novo aortic regurgitation was observed in 17 patients, 6 of whom developed at least moderate regurgitation during follow-up. Mid-term survival after Jarvik 2000 implantation was satisfactory and comparable to that reported by other national and international registries (INTERMACS and IMACS) for continuous-flow LVADs. De novo aortic regurgitation occurred despite the intermittent low-speed effect of this device, with some recipients experiencing progressive worsening of aortic regurgitation within 2 years post-implantation. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  4. Utilising three-dimensional printing techniques when providing unique assistive devices: A case report.

    Science.gov (United States)

    Day, Sarah Jane; Riley, Shaun Patrick

    2018-02-01

    The evolution of three-dimensional printing into prosthetics has opened conversations about the availability and cost of prostheses. This report will discuss how a prosthetic team incorporated additive manufacture techniques into the treatment of a patient with a partial hand amputation to create and test a unique assistive device which he could use to hold his French horn. Case description and methods: Using a process of shape capture, photogrammetry, computer-aided design and finite element analysis, a suitable assistive device was designed and tested. The design was fabricated using three-dimensional printing. Patient satisfaction was measured using a Pugh's Matrix™, and a cost comparison was made between the process used and traditional manufacturing. Findings and outcomes: Patient satisfaction was high. The three-dimensional printed devices were 56% cheaper to fabricate than a similar laminated device. Computer-aided design and three-dimensional printing proved to be an effective method for designing, testing and fabricating a unique assistive device. Clinical relevance CAD and 3D printing techniques can enable devices to be designed, tested and fabricated cheaper than when using traditional techniques. This may lead to improvements in quality and accessibility.

  5. Left ventricular assist device management in patients chronically supported for advanced heart failure.

    Science.gov (United States)

    Cowger, Jennifer; Romano, Matthew A; Stulak, John; Pagani, Francis D; Aaronson, Keith D

    2011-03-01

    This review summarizes management strategies to reduce morbidity and mortality in heart failure patients supported chronically with implantable left ventricular assist devices (LVADs). As the population of patients supported with long-term LVADs has grown, patient selection, operative technique, and patient management strategies have been refined, leading to improved outcomes. This review summarizes recent findings on LVAD candidate selection, and discusses outpatient strategies to optimize device performance and heart failure management. It also reviews important device complications that warrant close outpatient monitoring. Managing patients on chronic LVAD support requires regular patient follow-up, multidisciplinary care teams, and frequent laboratory and echocardiographic surveillance to ensure optimal outcomes.

  6. Numerical simulation of the pulsating catheter pump : A left ventricular assist device

    NARCIS (Netherlands)

    Verkerke, GJ; Mihaylov, D; Geertsema, AA; Lubbers, J; Rakhorst, G

    1999-01-01

    The pulsating catheter (PUCA) pump, a left ventricular assist device, consists of a hydraulically or pneumatically driven membrane pump, extracorporeally placed and mounted to a valved catheter. The catheter is introduced into an easily accessible artery and positioned with its distal tip in the

  7. Electric field and interface charge extraction in field-plate assisted RESURF devices

    NARCIS (Netherlands)

    Boksteen, B.K.; Heringa, Anco; Ferrara, A.; Steeneken, Peter G.; Schmitz, Jurriaan; Hueting, Raymond Josephus Engelbart

    2015-01-01

    A methodology for extracting the lateral electric field (Ex) in the drain extension of thin silicon-on-insulator high-voltage field-plate assisted reduced surface field (RESURF) devices is detailed including its limits and its accuracy. Analytical calculations and technology computer-aided design

  8. Extraction of the Electric Field in Field Plate Assisted RESURF Devices

    NARCIS (Netherlands)

    Boksteen, B.K.; Dhar, S.; Heringa, A.; Koops, G.E.J.; Hueting, Raymond Josephus Engelbart

    2012-01-01

    It has previously been reported that the lateral electric field (Ex) in the drain extension of thin SOI HV (700V) field plate assisted RESURF devices can be extracted from their ID-VD characteristics in the subthreshold regime. In this work the prerequisites for valid field extraction and the

  9. Recurrent Early Thrombus Formation in HeartMate II Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Massimo Capoccia MD, MSc

    2013-05-01

    Full Text Available Left ventricular assist devices are becoming an established treatment for end-stage heart failure. In spite of their proven benefit, pump thrombosis remains a significant complication. Here we describe the challenging management of a patient with recurrent pump thrombosis.

  10. Right ventricular failure after implantation of a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Cordtz, Johan Joakim; Nilsson, Jens C; Hansen, Peter B

    2014-01-01

    Right ventricular failure (RVF) is a significant complication after implantation of a left ventricular assist device. We aimed to identify haemodynamic changes in the early postoperative phase that predicted subsequent development of RVF in a cohort of HeartMate II (HMII) implanted patients....

  11. Left ventricular assist device implantation via left thoracotomy: alternative to repeat sternotomy.

    Science.gov (United States)

    Pierson, Richard N; Howser, Renee; Donaldson, Terri; Merrill, Walter H; Dignan, Rebecca J; Drinkwater, Davis C; Christian, Karla G; Butler, Javed; Chomsky, Don; Wilson, John R; Clark, Rick; Davis, Stacy F

    2002-03-01

    Repeat sternotomy for left ventricular assist device insertion may result in injury to the right heart or patent coronary grafts, complicating intraoperative and postoperative management. In 4 critically ill patients, left thoracotomy was used as an alternative to repeat sternotomy. Anastomosis of the outflow conduit to the descending thoracic aorta provided satisfactory hemodynamic support.

  12. Minimally Invasive Cochlear Implantation Assisted by Bi-planar Device: An Exploratory Feasibility Study in vitro

    Directory of Open Access Journals (Sweden)

    Jia Ke

    2016-01-01

    Conclusions: This exploratory study demonstrated the safety of the newly developed image-guided minimally invasive cochlear implantation assisted by the bi-planar device and established the operational procedures. Further, more in vitro experiments are needed to improve the system operation and its safety.

  13. Hemodynamic stress echocardiography in patients supported with a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Andersen, Mads; Gustafsson, Finn; Madsen, Per Lav

    2010-01-01

    Functional assessment of continuous-flow left ventricular assist devices (LVADs) is usually performed with the patient at rest. This study compared echocardiographic indices of contraction and filling pressure with invasive measures in 12 ambulatory LVAD patients undergoing symptom-limited bicycle...

  14. Intelligent speed adaptation as an assistive device for drivers with acquired brain injury

    DEFF Research Database (Denmark)

    Klarborg, Brith; Lahrmann, Harry Spaabæk; Agerholm, Niels

    2012-01-01

    Intelligent speed adaptation (ISA) was tested as an assistive device for drivers with an acquired brain injury (ABI). The study was part of the “Pay as You Speed” project (PAYS) and used the same equipment and technology as the main study (Lahrmann et al., in press-a, in press-b). Two drivers...

  15. Emergency ventricular assist device: better survival rates in non-post cardiotomy-related cardiogenic shock

    NARCIS (Netherlands)

    Rodrigus, I. E.; Amsel, B. J.; Conraads, V.; de Hert, S.; Moulijn, A. C.

    2001-01-01

    OBJECTIVE: The Abiomed BVS 5000 ventricular assist device (VAD) has been approved in Belgium for emergency cardiac support in patients with postcardiotomy failure with the aim of native heart function recovery. Other indications have emerged from world wide experience, but the indication and

  16. User Evaluation of the MOBOT Rollator Type Robotic Mobility Assistive Device

    Directory of Open Access Journals (Sweden)

    Yiannis Koumpouros

    2017-11-01

    Full Text Available In this paper, we report on the evaluation strategy and the results that were obtained from the final end-user evaluation process of an innovative robotic assistive device supporting mobility. More specifically, the paper deals with the evaluation of the MOBOT robotic rollator as regards to the system’s overall performance and its individual assistive characteristics and functionalities, as implemented in respect to (i the provided cognitive assistance, and (ii the adopted audio-gestural human-robot communication model. User evaluation was designed on the basis of an extensive survey of scales and methodologies widely reported in the relevant literature. The actual evaluation phase exploited the QUEST 2.0, ATDPA-Device Form, and PYTHEIA scales to measure the subjective satisfaction of the users. The PYTHEIA scale, in particular, was structured in order to fill the gaps that were identified during the study of previously existing tools for measuring assistive device user satisfaction. The scale was applied for the first time during the reported evaluation process. An analysis of the results showed that MOBOT was ranked very high by end users in all of the aspects addressed by the three employed assessment scales, thus providing significant evidence for positive acceptance of any industrialized outcome of the current prototype in the assistive robots market.

  17. Physical assistance devices in complex motor skill learning: benefits of a self-controlled practice schedule.

    Science.gov (United States)

    Wulf, G; Toole, T

    1999-09-01

    This study examines the effects of a self-controlled use of physical assistance devices on learning a complex motor skill (i.e., producing slalom-type movements on a ski simulator). Physical assistance was provided by ski poles. One group of learners (self-control) was provided with the poles whenever they requested them, whereas another (yoked) group had no influence on the pole/no-pole schedule. While there were no group differences during the practice phase (Days 1 and 2), clear group differences emerged in the retention test without poles (Day 3). The self-control group produced significantly larger amplitudes than the yoked group. These results extend previous findings by showing learning advantages of the self-controlled use of physical assistance devices in complex motor skill learning.

  18. AUDIS wear: a smartwatch based assistive device for ubiquitous awareness of environmental sounds.

    Science.gov (United States)

    Mielke, Matthias; Bruck, Rainer

    2016-08-01

    A multitude of assistive devices is available for deaf people (i.e. deaf, deafened, and hard of hearing). Besides hearing and communication aids, devices to access environmental sounds are available commercially. But the devices have two major drawbacks: 1. they are targeted at indoor environments (e.g. home or work), and 2. only specific events are supported (e.g. the doorbell or telephone). Recent research shows that important sounds can occur in all contexts and that the interests in sounds are diverse. These drawbacks can be tackled by using modern information and communication technology that enables the development of new and improved assistive devices. The smartwatch, a new computing platform in the form of a wristwatch, offers new potential for assistive technology. Its design promises a perfect integration into various different social contexts and thus blends perfectly into the user's life. Based on a smartwatch and algorithms from pattern recognition, a prototype for awareness of environmental sounds is presented here. It observes the acoustic environment of the user and detects environmental sounds. A vibration is triggered when a sound is detected and the type of sound is shown on the display. The design of the prototype was discussed with deaf people in semi-structured interviews, leading to a set of implications for the design of such a device.

  19. Embodying prostheses - how to let the body welcome assistive devices. Comment on "The embodiment of assistive devices-from wheelchair to exoskeleton" by M. Pazzaglia and M. Molinari

    Science.gov (United States)

    Longo, Matthew R.; Sadibolova, Renata; Tamè, Luigi

    2016-03-01

    A growing body of research has focused on the development of assistive devises to improve the recovery and ameliorate the quality of life of people suffering from spinal cord injuries (SCI). In their stimulating and timely paper, Pazzaglia and Molinari [1] review the significant progress made by biotechnology studies in providing increasing sophisticated assistive tools (e.g., prostheses and exoskeletons) that extend the functionality of patients' bodies. However, despite this extraordinary technological effort [2], it remains uncertain how these devices can be appropriately embedded into the mental representation of the body. Here, we wish to amplify the points raised by Pazzaglia and Molinari by discussing three challenges facing work on embodying prostheses raised by experimental research on body representation.

  20. Ventricular assist devices for heart failure: a focus on patient selection and complications

    Directory of Open Access Journals (Sweden)

    Cipriani M

    2014-09-01

    Full Text Available Manlio Cipriani, Vincenzo De Simone, Luciana D'Angelo, Enrico Perna, Marzia Lilliu, Virginia Bovolo, Fabrizio Oliva, Maria Frigerio Cardiovascular and Thoracic Department, A De Gasperis Niguarda Ca' Granda Hospital, Milan, Italy Abstract: Heart transplantation represents the “gold standard” for the treatment of patients with end-stage heart failure, but remains challenged by inadequate donor supply, finite graft survival, and long-term complications arising from immunosuppressive therapy. In addition, a lot of patients waiting for a heart transplant experience clinical deterioration, and other patients become ineligible to undergo this treatment due to their age or relevant comorbidities. Left ventricular assist devices have emerged as a valid therapeutic option for advanced heart failure. In recent years, we have seen significant advances not only in the technologies available, but also in patient selection, indications for use, and management after implantation. Consequently, there has been an increase in the number of implants and an improvement in the survival rate and quality of life for these patients. At the same time, there are new challenges on the horizon. Patient selection is a difficult process, based on clinical and imaging parameters and risk scores, and more data are needed to refine patient selection criteria and the timing of the implant. Left ventricular assist device-related complications are still a serious problem, causing adverse events and hospital readmissions. Continuous progress in the development of these implantable devices, such as a further reduction in size and hopefully the abolition of the external driveline, will probably make ventricular assist devices an option also for less advanced stages of heart failure. Here, we discuss the current indications for left ventricular assist device implantation, patient selection criteria, and the most frequent complications associated with these devices. Keywords

  1. Total artificial heart freedom driver in a patient with end-stage biventricular heart failure.

    Science.gov (United States)

    Friedline, Kristin; Hassinger, Pamela

    2012-04-01

    Approximately 5.7 million people in the United States have a diagnosis of heart failure, and more than 3,100 patients are awaiting a heart transplant. A temporary total artificial heart (TAH-t, SynCardia Systems Inc, Tucson, Arizona) is approved by the US Food and Drug Administration (FDA) as a bridge to transplant in patients at risk of dying of biventricular heart failure. Currently, TAH-t recipients awaiting transplant are hospital-bound and attached to a large pneumatic driver. In 2010, the FDA gave conditional approval for an Investigational Device Exemption clinical study of the portable Freedom driver (SynCardia). This case report describes a 61-year-old man admitted with acute decompensated heart failure, which progressively worsened, eventually requiring implantation of a TAH-t. Following stabilization, the patient was switched to the Freedom driver. After the patient and his wife proved competence in managing the device, they were able to take several daylong excursions outside the hospital. The patient considered discharge from the hospital while awaiting a transplant but ultimately received a heart transplant while still an inpatient. Higher rates of survival to transplant have already been proved with the TAH-t. Potential benefits for the portable Freedom driver include increased mobility, decreased cost, and improved quality of life.

  2. 49 CFR 39.93 - What wheelchairs and other assistive devices may passengers with a disability bring onto a...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What wheelchairs and other assistive devices may passengers with a disability bring onto a passenger vessel? 39.93 Section 39.93 Transportation Office of the... and Services to Passengers With Disabilities § 39.93 What wheelchairs and other assistive devices may...

  3. A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

    Directory of Open Access Journals (Sweden)

    Guilian Wang

    2018-01-01

    Full Text Available The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals’ inputs, respectively, and then the types of elliptic and Lissajous’s vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

  4. A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

    Science.gov (United States)

    Wang, Guilian; Zhou, Xiaoqin; Ma, Peiqun; Wang, Rongqi; Meng, Guangwei; Yang, Xu

    2018-01-01

    The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals' inputs, respectively, and then the types of elliptic and Lissajous's vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

  5. Foil assisted replica molding for fabrication of microfluidic devices and their application in vitro.

    Science.gov (United States)

    Micheal, Issac J; Vidyasagar, Aditya J; Bokara, Kiran Kumar; Mekala, Naveen Kumar; Asthana, Amit; Rao, Ch Mohan

    2014-10-07

    We present a simple, rapid, benchtop, Foil Assisted Rapid Molding (FARM) method for the fabrication of microfluidic devices. This novel technique involves the use of aluminium foil, pen and an X-Y plotter to create semi-circular or plano-concave, shallow microchannels. It is an easy do-it-yourself (DIY) technique for creating a microfluidic device in three simple steps: (1) create a channel design using the CAD software, (2) plot the patterns on aluminium foil and (3) use the reverse of the engraved foil as a mold to create microfluidic devices. In this report, we present a detailed study of the proposed method by varying a range of parameters such as foil thickness, tip material, and tip sizes and by investigating their effect on the creation of channels with varying geometry. Furthermore, we demonstrated the cytocompatibility of these devices in vitro.

  6. Laminated Copper Nanocluster Incorporated Antioxidative Paper Device with RGB System-Assisted Signal Improvement

    Directory of Open Access Journals (Sweden)

    Chong-You Chen

    2018-02-01

    Full Text Available Paper-based analytical devices are an emerging class of lightweight and simple-to-use analytical platform. However, challenges such as instrumental requirements and chemical reagents durability, represent a barrier for less-developed countries and markets. Herein, we report an advanced laminated device using red emitting copper nanocluster and RGB digital analysis for signal improvement. Upon RGB system assistance, the device signal-to-background ratio and the calibration sensitivity are highly enhanced under a filter-free setup. In addition, the calibration sensitivity, limit of detection, and coefficient of determination are on par with those determined by instrumental fluorescence analysis. Moreover, the limitation of using oxidation-susceptible fluorescent nanomaterials is overcome by the introduction of protecting tape barriers, antioxidative sheets, and lamination enclosing. The robustness of device is highly advanced, and the durability is prolonged to more than tenfold.

  7. Combined spinal-epidural anesthesia for cesarean delivery in a patient with cor triloculare biventriculare.

    Science.gov (United States)

    Han, Yuan; Zhang, Zhenfeng; Sun, Qingchun; Ding, Ke; Han, Liu; Dong, Mengmeng; Xu, Yifan; Ge, Lei

    2017-08-29

    Cor triloculare biventriculare accounts for approximately 0.31% of cases of congenital heart disease (CHD). Moreover, people with cor triloculare biventriculare always have shorter life spans, and cases of gestation are rare. There have been various related reports of cor triloculare biventriculare in recent years. We described an emergency cesarean section of a 30-year-old, 38-weeks-pregnant woman suffering from cardiac insufficiency and fetal distress. Combined spinal-epidural anesthesia was performed safely, and a male baby was smoothly delivered 10 min after the procedure without any adverse outcome on the mother or newborn. After surgery, we advised that the patient submit to an echocardiogram examination, which revealed the congenital heart disease cor triloculare biventriculare. Combined spinal-epidural anesthesia was administered to a patient with cor triloculare biventricularethis with good effect, ensuring the patient's safety and meeting the need for emergency surgery.

  8. The impact of mobility assistive technology devices on participation for individuals with disabilities.

    Science.gov (United States)

    Carver, Jordan; Ganus, Ashley; Ivey, Jon Mark; Plummer, Teresa; Eubank, Ann

    2016-08-01

    This study aims to address the gap in research and contribute to the body of knowledge on the perspectives assistive technology device users have toward their devices. Mixed methods were used to better understand the impact of mobility assistive technology devices (MATDs) on participation for individuals with disabilities. The Functional Mobility Assessment was administered in conjunction with two qualitative questions developed by the research team allowing participants to expound on the impact of their MATD experience. Participants were recruited online via the National Spinal Cord Injury Association website and in-person at Abilities Expo in Atlanta, Georgia, and the International Seating Symposium in Nashville, Tennessee. Results are consistent with findings from prior research regarding accessibility for individuals with disabilities. Corresponding findings were found in both the quantitative and qualitative data and are categorized into several major themes: environment (indoor and outdoor), surface heights, transportation, dependence, independence, quality of life and participation. Quantitative data from this study indicate that users of MATD are satisfied with the way in which their devices enable maneuvering indoors, while qualitative data suggest otherwise. Implications for healthcare practitioners are described and future recommendations are provided. Implications for Rehabilitation Healthcare professionals should advocate for proper mobility assistive technology devices (MATDs) for their patients in order to enable increased independence, safety and efficiency. Healthcare professionals must be cognizant of the impact of the environment and/or environmental barriers when prescribing MATD. Additional areas of interest for future research may include investigating the impact of MATD in association with date of onset of disability, according to diagnoses, or specific to length of time since acquiring the device.

  9. Internal vacuum-assisted closure device in the swine model of severe liver injury

    Directory of Open Access Journals (Sweden)

    Everett Christopher B

    2012-12-01

    Full Text Available Abstract Objectives The authors present a novel approach to nonresectional therapy in major hepatic trauma utilizing intraabdominal perihepatic vacuum assisted closure (VAC therapy in the porcine model of Grade V liver injury. Methods A Grade V injury was created in the right lobe of the liver in a healthy pig. A Pringle maneuver was applied (4.5 minutes total clamp time and a vacuum assisted closure device was placed over the injured lobe and connected to suction. The device consisted of a perforated plastic bag placed over the liver, followed by a 15 cm by 15cm VAC sponge covered with a nonperforated plastic bag. The abdomen was closed temporarily. Blood loss, cardiopulmonary parameters and bladder pressures were measured over a one-hour period. The device was then removed and the animal was euthanized. Results Feasibility of device placement was demonstrated by maintenance of adequate vacuum suction pressures and seal. VAC placement presented no major technical challenges. Successful control of ongoing liver hemorrhage was achieved with the VAC. Total blood loss was 625 ml (20ml/kg. This corresponds to class II hemorrhagic shock in humans and compares favorably to previously reported estimated blood losses with similar grade liver injuries in the swine model. No post-injury cardiopulmonary compromise or elevated abdominal compartment pressures were encountered, while hepatic parenchymal perfusion was maintained. Conclusion These data demonstrate the feasibility and utility of a perihepatic negative pressure device for the treatment of hemorrhage from severe liver injury in the porcine model.

  10. Left ventricular assist device as bridge to recovery for anthracycline-induced terminal heart failure.

    Science.gov (United States)

    Appel, Jon M; Sander, Kåre; Hansen, Peter B; Møller, Jacob E; Krarup-Hansen, Anders; Gustafsson, Finn

    2012-01-01

    Anthracycline treatments are hampered by dose-related cardiotoxicity, frequently leading to heart failure (HF) with a very poor prognosis. The authors report a case of a 19-year-old man developing HF after anthracycline treatment for Ewing sarcoma. Despite medical treatment, his condition deteriorated to terminal HF, leading to implantation of a mechanical left ventricular assist device (LVAD). His heart function recovered, allowing explantation of the device 14 months after implantation. Heart transplantation is often contraindicated in the first years after treatment for cancers, and LVAD as "bridge to recovery" may be warranted in similar patients. © 2012 Wiley Periodicals, Inc.

  11. Pre-ejection period by radial artery tonometry supplements echo doppler findings during biventricular pacemaker optimization

    Directory of Open Access Journals (Sweden)

    Qamruddin Salima

    2011-07-01

    Full Text Available Abstract Background Biventricular (Biv pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP assessment by radial artery tonometry in guiding Biv pacemaker optimization. Methods Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV ejection fraction (EF 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI, ejection time (ET, myocardial performance index (MPI, radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated. Results Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p Conclusion An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.

  12. Does reduced movement restrictions and use of assistive devices affect rehabilitation outcome after total hip replacement?

    DEFF Research Database (Denmark)

    Mikkelsen, Lone Ramer; Petersen, Annemette Krintel; Søballe, Kjeld

    2014-01-01

    ). This group was compared to patients included the following 3 months with less restricted hip movement and use of assistive devices according to individual needs (unrestricted group). Questionnaires on function, pain, quality of life (HOOS), anxiety (HADS), working status and patient satisfaction were...... completed before THR, 3 and 6 weeks after. RESULTS: The HOOS function score at the 3 measurement times was (mean ± SD); unrestricted group: 46 ± 17 - 76 ± 9 - 83 ± 14 compared to restricted group: 43 ± 16 - 81 ± 14 - 83 ± 13. Changes over time was significantly higher in the restricted group (P=0...... slower recovery in patient-reported function after reduction in movement restrictions and use of assistive devices, but the difference was eliminated after 6 weeks. Reduced movement restrictions did not affect the other patient-reported outcomes and led to earlier return to work. CLINICAL REHABILITATION...

  13. Does reduced movement restrictions and use of assistive devices affect rehabilitation outcome after total hip replacement?

    DEFF Research Database (Denmark)

    Mikkelsen, Lone Ramer; Petersen, Annemette Krintel; Søballe, Kjeld

    2014-01-01

    BACKGROUND: Improvements in surgical techniques and increase of femoral head size might have changed the rationale for movement restrictions after total hip replacement (THR). AIM: To evaluate the influence of movement restrictions and assistive devices on rehabilitation after fast track THR. DES...... IMPACT: It is possible to reduce movement restrictions and use of assistive devices considerably. More research on safety issues is needed to elucidate the effect of unrestricted rehabilitation on hip dislocation....... completed before THR, 3 and 6 weeks after. RESULTS: The HOOS function score at the 3 measurement times was (mean ± SD); unrestricted group: 46 ± 17 - 76 ± 9 - 83 ± 14 compared to restricted group: 43 ± 16 - 81 ± 14 - 83 ± 13. Changes over time was significantly higher in the restricted group (P=0...

  14. Left Ventricular Assist Device Thrombosis-Amiodarone-Induced Hyperthyroidism: Causal Link?

    Science.gov (United States)

    Rajapreyar, Indranee; Acharya, Deepak; Tallaj, José; Hornbuckle, Lauren; Sharpton, Jessica; Joly, Joanna; Pamboukian, Salpy

    2018-03-05

    Ventricular arrhythmias occurs in 20-50% of patients supported with left ventricular assist devices (LVAD). Ventricular arrhythmias are well tolerated with LVAD support but long-term consequences include worsening right ventricular function. Management of ventricular arrhythmias in LVAD patients includes use of antiarrhythmic agents or ablation. Amiodarone has been used a first-line agent to treat ventricular arrhythmias post-LVAD implantation. Chronic treatment with amiodarone for arrhythmias can result in hyperthyroidism and hypothyroidism in 5-10% of patients. Hyperthyroidism is known to cause endothelial dysfunction, alterations in coagulation, and fibrinolytic pathways favoring hypercoagulable state. We describe two cases of left ventricular assist device (LVAD) thrombosis potentiated by amiodarone-induced hyperthyroidism (AIT) and discuss pathophysiological mechanisms for hypercoagulable state induced by hyperthyroidism.

  15. Numerical simulation of left ventricular assist device implantations: comparing the ascending and the descending aorta cannulations.

    Science.gov (United States)

    Bonnemain, Jean; Malossi, A Cristiano I; Lesinigo, Matteo; Deparis, Simone; Quarteroni, Alfio; von Segesser, Ludwig K

    2013-10-01

    In this work we present numerical simulations of continuous flow left ventricle assist device implantation with the aim of comparing difference in flow rates and pressure patterns depending on the location of the anastomosis and the rotational speed of the device. Despite the fact that the descending aorta anastomosis approach is less invasive, since it does not require a sternotomy and a cardiopulmonary bypass, its benefits are still controversial. Moreover, the device rotational speed should be correctly chosen to avoid anomalous flow rates and pressure distribution in specific location of the cardiovascular tree. With the aim of assessing the differences between these two approaches and device rotational speed in terms of flow rate and pressure waveforms, we set up numerical simulations of network of one-dimensional models where we account for the presence of an outflow cannula anastomosed to different locations of the aorta. Then, we use the resulting network to compare the results of the two different cannulations for several stages of heart failure and different rotational speed of the device. The inflow boundary data for the heart and the cannulas are obtained from a lumped parameters model of the entire circulatory system with an assist device, which is validated with clinical data. The results show that ascending and descending aorta cannulations lead to similar waveforms and mean flow rate in all the considered cases. Moreover, regardless of the anastomosis region, the rotational speed of the device has an important impact on wave profiles; this effect is more pronounced at high RPM. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Starting assistance device for directly-driven electric vehicle with variable-idle speed control

    OpenAIRE

    Xiong, Ping; Gu, Chenglin

    2017-01-01

    By introducing a novel permanent magnetic bi-stable electromagnetic clutch unit (PMBECU) in the driveline of directly-driven electric vehicle, a flexible connection between motor and hub is realized with characteristic of separated starting process of drive motor and wheel load. Firstly, the working principle and power supply scheme for the PMBECU is discussed. Then the assembly for the wheel-drive system with starting assistance device by the clutch is investigated. Considering the good dyna...

  17. Implantation of left ventricular assist device in a patient with left ventricular non-compaction.

    Science.gov (United States)

    Balsara, Keki R; Bierhals, Andrew; Vader, Justin; Pasque, Michael K; Itoh, Aki

    2017-02-01

    Left ventricular noncompaction (LVNC) may result in systolic left ventricular (LV) failure resulting in the need for heart transplantation. LV assist devices (LVAD) have been used to bridge these patients to transplantation; however, the extensive trabeculations found in these patients predispose them to thromboembolic events and pump thrombosis. We describe a patient with LVNC in whom an aggressive surgical approach was used to debride the LV cavity of trabeculations to successfully implant an LVAD. © 2017 Wiley Periodicals, Inc.

  18. A wound retraction device for laparoscopic-assisted intestinal surgery in dogs and cats.

    Science.gov (United States)

    Gower, Sara B; Mayhew, Philipp D

    2011-06-01

    To report experience with laparoscopic-assisted intestinal resection and anastomosis for treatment of discrete intestinal masses using a novel wound retraction device. Case series. Dogs (n=2) and cats (6). Dogs and cats with discrete intestinal masses identified by ultrasonography without evidence of intestinal perforation or peritonitis, were included. A 2 portal technique was used; 1 portal was enlarged for insertion of the wound retraction device through which the intestine was examined as thoroughly as possible. The diseased portion of the intestine was exteriorized through the wound retractor and resection and anastomosis of the intestinal mass performed. Of the 8 animals, laparoscopic-assisted intestinal resection and anastomosis through the wound retractor was performed in 2 dogs and 3 cats. In 3 cats, based on either location or extent of the lesion, 2 were converted to laparoscopic-assisted intestinal biopsies and 1 to an open colocolostomy. No other intra- or perioperative complications were encountered and all animals survived to discharge. Laparoscopic-assisted intestinal resection and anastomosis can be performed in select canine and feline patients with modestly sized, discrete intestinal masses. © Copyright 2011 by The American College of Veterinary Surgeons.

  19. A device for training and computer-assisted application of panretinal photocoagulation

    Science.gov (United States)

    Barriga, Eduardo S.; Russell, Stephen; Abramoff, Michael; Brittain, Robert; Nguyen, Phong; Soliz, Peter

    2007-02-01

    To become highly proficient at a given surgical procedure and to reduce risk to patients, physicians must gain experience through a number means. Today optical training devices based on the actual surgical device coupled with computer models can provide the required realism to provide highly effective training. This paper presents a optical system that will be used for training residents to perform panretinal photocoagulation (PRP), a laser surgical procedure for treating the retina. The system will naturally evolve into a computer-assisted device for performing PRP. With the system described herein, simulations are created in the Umbra modeling and simulation framework. The simulation is composed of four building blocks: Pre-operation planning, multi-modality image registration, tracking the patient's eye movement, and positioning the laser according to the pre-planned aim points. A prototype simulation was developed to demonstrate a realistic depiction of the PRP the procedure. The ultimate goal of this project is to integrate the software into an existing ophthalmic device to increase the accuracy of the laser application procedure by providing computer-assisted surgery.

  20. [Tracheal intubation with Parker Flex-Tip tubes assisted by tube-guiding devices].

    Science.gov (United States)

    Mizuno, Ju; Morita, Shigeho; Suzuki, Maya; Arita, Hideko; Hanaoka, Kazuo

    2010-04-01

    In tracheal intubation assisted by tube-guiding devices passing through the tube, such as fiberoptic scopes, bougies, tracheal tube exchange catheters, and light wands, passage of the tube-guiding device, by itself, is often easy. But advancing a tracheal tube with a conventional distal tip over these tube-guiding devices is frequently difficult or impossible, because its rigid, side-beveled tip frequently catches on anatomical features of the airway. A novel tracheal tube, the Parker Flex-Tip tube (Parker Medical, Colorado, USA) has a centered, curved, tapered and flexible distal tip that passes through the airway faster and easier than conventional tracheal tubes. As it is advanced along a tube-guiding device, the tip of the Parker tube travels along the midline of the airway, without the gap that usually exists between the distal edge of a conventional tracheal tube and the tube-guiding device. The gapless, midline travel of the Parker tube leads to a greater incidence of first-attempt intubation success with tube-guiding devices, because there is less risk of tube tip hang-ups on the arytenoids and the vocal cords. Clinically, use of the Parker tube is helpful for oral and nasal intubations, especially in patients with difficult airways.

  1. A Numerical Analysis of Phononic-Assisted Control of Ultrasound Waves in Acoustofluidic Device

    Science.gov (United States)

    Moiseyenko, Rayisa P.; Bruus, Henrik

    The ability to precisely sort individual microparticles/cells/droplets in suspension is important for various chemical and biological applications such as cancer cell detection, drug screening etc. The past decade, label- free particle handling of particle suspensions by ultrasonic radiation forces and streaming has received much attention, since it relies solely on mechanical properties such as particle size and contrast in density and compressibility. We present a theoretical study of phononic-assisted control of ultrasound waves in acoustofluidic devices. We propose the use of phononic crystal diffractors, which can be introduced in acoustofluidic structures. These diffractors can be applied in the design of efficient resonant cavities, directional sound waves for new types of particle sorting methods, or acoustically controlled deterministic lateral displacement. The PnC-diffractor-based devices can be made configurable, by embedding the diffractors, all working at the same excitation frequency but with different resulting diffraction patterns, in exchangeable membranes on top of the device.

  2. Stroke rehabilitation: assistive technology devices and environmental modifications following primary rehabilitation in hospital--a therapeutic perspective

    DEFF Research Database (Denmark)

    Sørensen, Hanne Vinkel; Lendal, Susie; Schultz-Larsen, Kirsten

    2003-01-01

    The aim of this article is to describe the need for assistive devices and environmental modifications among long-living stroke survivors and to investigate if the need is continued and growing over time. The study sample of 155 consecutive stroke patients with stroke-related impairment, discharged...... home from three hospitals in Copenhagen from 1996 through 1998, constituted 20% of the total population of stroke survivors in this area. The results showed that 75% of these patients were provided with assistive devices and/or environmental modifications at discharge. Six months after discharge...... be required in order to target stroke survivors' changing needs for assistive devices and environmental modifications....

  3. Objective and perceptual comparisons of two bluetooth hearing aid assistive devices.

    Science.gov (United States)

    Clark, Jackie L; Pustejovsky, Carmen; Vanneste, Sven

    2017-08-01

    With the advent of Bluetooth technology, many of the assistive listening devices for hearing have become manufacturer specific, with little objective information about the performance provided. Thirty native English-speaking adults (mean age 29.8) with normal hearing were tested pseudo-randomly with two major hearing aid manufacturers' proprietary Bluetooth connectivity devices paired to the accompanying manufacturer's specific hearing aids. Sentence recognition performance was objectively measured for each system with signals transmitted via a land-line to the same iPhone in two conditions. There was a significant effect of participant's performance according to listening condition. There was no significant effect between device manufacturers according to listening condition, but there was a significant effect in participant's perception of "quality of sound". Despite differences in signal transmission for each devise, when worn by participants both the systems performed equally. In fact, participants expressed personal preferences for specific technology that was largely due to their perceived quality of sound while listening to recorded signals. While further research is necessary to investigate other measures of benefit for Bluetooth connectivity devices, preliminary data suggest that in order to ensure comfort and compatibility, not only should objective measures of the patient benefit be completed, but also assessing the patient's perception of benefit is equally important. Implications for Rehabilitation All professionals who work with individuals with hearing loss, become aware of the differences in the multiple choices for assistive technology readily available for hearing loss. With the ever growing dispensing of Bluetooth connectivity devices coupled to hearing aids, there is an increased burden to determine whether performance differences could exist between manufacturers. There is a growing need to investigate other measures of benefit for Bluetooth

  4. Use of and Self-Perceived Need for Assistive Devices in Individuals with Disabilities in Taiwan.

    Directory of Open Access Journals (Sweden)

    Kwok-Tak Yeung

    Full Text Available Assistive devices (ADs can help individuals with disabilities achieve greater independence, and it can enhance the quality of their lives. This study investigated the use of and self-perceived need for ADs in individuals with disabilities, and determined the influence of gender, age as well as type and degree of disability on the use of and self-perceived need for ADs. This descriptive study utilized a cross-sectional survey design with a convenience sample of participants. A total of 1018 subjects with disabilities who visited an exhibition of assistive technology and two ADs research and development centers completed a questionnaires either by themselves or via a caregiver who completed the questionnaire on behalf of the subject or via interviewers trained specifically for this study. The Mann-Whitney U test and Kruskal-Wallis test were used to determine the influence of participant characteristics on the use of ADs. The results showed that 77.2% and 83.3% of the participants reported that they used and needed AD(s to engage in activities of daily living. The mean quantity of the use of and self-perceived need for total types of ADs were 3.0 and 5.3, respectively. Participants with different disabilities reported different percentages of the use of various types of ADs. No difference was found between genders and among the age groups in the use of quantity of ADs. Individuals with different types and degrees of disability used different quantities of ADs. Participants with physical, visual and multiple disabilities used significantly more ADs compared to participants with intellectual disability. The total quantity of ADs used increased significantly with increased severity of disability. The mean use of assistive devices was lower compared to the mean need of individuals with disabilities. Further study is required to determine why patients feel the need for but not currently use a specific assistive device.

  5. Use of and Self-Perceived Need for Assistive Devices in Individuals with Disabilities in Taiwan.

    Science.gov (United States)

    Yeung, Kwok-Tak; Lin, Chung-Hui; Teng, Ya-Ling; Chen, Fen-Fen; Lou, Shu-Zon; Chen, Chiung-Ling

    2016-01-01

    Assistive devices (ADs) can help individuals with disabilities achieve greater independence, and it can enhance the quality of their lives. This study investigated the use of and self-perceived need for ADs in individuals with disabilities, and determined the influence of gender, age as well as type and degree of disability on the use of and self-perceived need for ADs. This descriptive study utilized a cross-sectional survey design with a convenience sample of participants. A total of 1018 subjects with disabilities who visited an exhibition of assistive technology and two ADs research and development centers completed a questionnaires either by themselves or via a caregiver who completed the questionnaire on behalf of the subject or via interviewers trained specifically for this study. The Mann-Whitney U test and Kruskal-Wallis test were used to determine the influence of participant characteristics on the use of ADs. The results showed that 77.2% and 83.3% of the participants reported that they used and needed AD(s) to engage in activities of daily living. The mean quantity of the use of and self-perceived need for total types of ADs were 3.0 and 5.3, respectively. Participants with different disabilities reported different percentages of the use of various types of ADs. No difference was found between genders and among the age groups in the use of quantity of ADs. Individuals with different types and degrees of disability used different quantities of ADs. Participants with physical, visual and multiple disabilities used significantly more ADs compared to participants with intellectual disability. The total quantity of ADs used increased significantly with increased severity of disability. The mean use of assistive devices was lower compared to the mean need of individuals with disabilities. Further study is required to determine why patients feel the need for but not currently use a specific assistive device.

  6. [Vectorcardiographic manifestations of left ventricular and biventricular enlargement].

    Science.gov (United States)

    de Micheli, A; Medrano, G A

    1979-01-01

    The basic criteria for the vectorcardiographic diagnosis of left ventricular and biventricular enlargements are discussed on the basis of the myocardial activation sequence. Left ventricular dilatation, secondary to isolated diastolic overloading, increases the manifestation of all the vectors resulting of the activation of this ventricle. These changes reflect the proximity of the left ventricular walls to the exploring electrodes. The vectors above mentioned project themselves as wide ventricular curves with counterclockwise rotation on the three planes. The T loop, of secondary type, is concordant in its orientation with the R loop. Cases with left ventricular hypertrophy, produced by a sustained systolic overloading, are also described. In the presence of global left ventricular hypertrophy without LBBB, the manifestation of all the vectors resulting from the depolarization of this ventricle (I, IIl, IIIl), is increased. This is due to a prolonged duration of the corresponding activation fronts. These vectors are projected on the different segments of the ventricular curves and they show a counterclockwise rotation on the three planes. When LBBB is also present, the first septal vector is not evident. The T loop, of secondary type, opposes the R loop on the frontal and horizontal planes. The presence of left ventricular hypertrophy of the segmentary type, generally increases the manifestation of the vector I, and sometimes, also that of the vector IIIl. When both ventricles are hypertrophied, the electromotive forces of the chamber more severely affected predominate in the vectorcardiographic records.

  7. An ambulatory pulmonary and right heart assist device (OxyRVAD) in an ovine survival model.

    Science.gov (United States)

    Wang, Dongfang; Zhou, Xiaoqin; Lick, Scott D; Liu, Xiaojun; Qian, Kunxi; Zwischenberger, Joseph B

    2007-10-01

    To develop ambulatory total respiratory and right heart assistance for up to 4 weeks as a bridge to lung transplantation, we coupled a compact gas exchange device with a right ventricular assist device (RVAD), a compact rotary blood pump, to create an "OxyRVAD." Our ambulatory OxyRVAD includes a portable (4 x 4 x 7-cm) centrifugal pump with heparin saline-purged needle roller bearings and an ultra-low-resistant gas exchange device (BioLung, MC3, Ann Arbor, MI). In 6 anesthetized sheep, the main pulmonary artery (PA) and right atrium (RA) were exposed through a left fourth intercostal thoracotomy. A 12-mm outer diameter vascular graft was anastomosed (end-to-side) to the main PA, and a VAD atrial cannula was placed into RA through the RA appendage. The pump and gas exchange device were interposed in circuit for RA-PA support. All 6 sheep survived OxyRVAD insertion. Four sheep survived the 5-day experiment. One was euthanized at 48 hours owing to pump electrical failure (wiring) and another at 72 hours owing to pump bearing failure (broken heparin purge line). One sheep needed replacement of a BioLung due to internal thrombi. OxyRVAD flow was stable (range, 3.57-4.30 liters/min). Carbon dioxide removal was constant during experiment (range, 88.35 +/- 6.12 ml/min at onset to 141.38 +/- 5.48 ml/min at the 96th hour). Oxygen transfer decreased from 161.8 +/- 8.8 to 79.7 +/- 31.4 ml/min at the 96th hour (p = 0.045). Our ambulatory OxyRVAD provided total assistance of right heart and lungs in normal awake sheep for up to 5 days.

  8. Physical interface dynamics alter how robotic exosuits augment human movement: implications for optimizing wearable assistive devices.

    Science.gov (United States)

    Yandell, Matthew B; Quinlivan, Brendan T; Popov, Dmitry; Walsh, Conor; Zelik, Karl E

    2017-05-18

    Wearable assistive devices have demonstrated the potential to improve mobility outcomes for individuals with disabilities, and to augment healthy human performance; however, these benefits depend on how effectively power is transmitted from the device to the human user. Quantifying and understanding this power transmission is challenging due to complex human-device interface dynamics that occur as biological tissues and physical interface materials deform and displace under load, absorbing and returning power. Here we introduce a new methodology for quickly estimating interface power dynamics during movement tasks using common motion capture and force measurements, and then apply this method to quantify how a soft robotic ankle exosuit interacts with and transfers power to the human body during walking. We partition exosuit end-effector power (i.e., power output from the device) into power that augments ankle plantarflexion (termed augmentation power) vs. power that goes into deformation and motion of interface materials and underlying soft tissues (termed interface power). We provide empirical evidence of how human-exosuit interfaces absorb and return energy, reshaping exosuit-to-human power flow and resulting in three key consequences: (i) During exosuit loading (as applied forces increased), about 55% of exosuit end-effector power was absorbed into the interfaces. (ii) However, during subsequent exosuit unloading (as applied forces decreased) most of the absorbed interface power was returned viscoelastically. Consequently, the majority (about 75%) of exosuit end-effector work over each stride contributed to augmenting ankle plantarflexion. (iii) Ankle augmentation power (and work) was delayed relative to exosuit end-effector power, due to these interface energy absorption and return dynamics. Our findings elucidate the complexities of human-exosuit interface dynamics during transmission of power from assistive devices to the human body, and provide insight into

  9. Virtual implantation and patient-specific simulation for optimization of outcomes in ventricular assist device recipients.

    Science.gov (United States)

    Anselmi, Amedeo; Collin, Sophie; Haigron, Pascal; Verhoye, Jean-Philippe; Flecher, Erwan

    2016-06-01

    Left ventricular assist devices (LVAD) are increasingly used for long-term mechanical circulatory support and are effective in improving survival and quality-of-life of patient with advanced heart failure. Nonetheless, they are associated with significant early and late morbidity rates (including pump thrombosis, thromboembolic events, and pump dysfunction). These complications are at least partially associated with suboptimal pump positioning. Currently, we are missing tools to further improve the positioning of LVAD devices in a patient-specific fashion. We hypothesized that the analysis of the implanted device in patients presenting selected LVAD-related complications through segmentation and three-dimensional reconstruction of CT scans may provide patient-specific information into mechanical factors contributing to pump dysfunction and thromboembolic events, with potential to guide preventive interventions against development of new complications. We also hypothesized that preoperative virtual implantation and computer-assisted surgery in candidates to LVAD implantation may help in the customization of device positioning, with potential to minimize severe complications. The hypothesis was evaluated in a multidisciplinary fashion (cardiac surgeons, biomedical engineers and biomedical images processing experts). CT scans of 14 LVAD recipients were reconstructed through semi-automatic segmentation (including the whole heart, the implanted device and the chest wall). A coordinate system was built to quantify the coaxiality of the LVAD apical cannula with the mitral annulus. Patients were stratified into Group 1 (presenting complications such as thromboembolic events, pump dysfunction or thrombosis) and Group 2 (no complications). Group 1 patients presented significantly greater average rotation of the apical cannula towards the interventricular septum (p=0.015), although no difference was observed in terms of average rotation towards the anterior or posterior left

  10. Cross-cultural adaptation of the psychosocial impact of assistive device scale (PIADS) for Puerto Rican assistive technology users.

    Science.gov (United States)

    Orellano, Elsa M; Jutai, Jeffrey W

    2013-01-01

    Assistive technology (AT) is important for individuals with disabilities' independence and participation in daily life, and there is a lack of valid AT outcome tools for the Puerto Rican population. This pilot study examined the content validity of a new adaptation of the Psychosocial Impact of Assistive Device Scale (PIADS): the Puerto Rican-Spanish PIADS (PR-PIADS). Following standard procedures, the cultural adaptation methodology included a bilingual multidisciplinary committee review of the original (English language) and Spanish versions of the PIADS and pilot testing of the preliminary version of the PR-PIADS with 20 AT users. The committee recommended a total of 58 semantic and conceptual modifications of the Spanish PIADS. Pilot data analysis resulted in 4 additional semantic and conceptual modifications of items that did not reach the minimum content validity ratio of 0.42 for a panel composed by 20 members: competence (0), efficiency (-0.6), performance (-0.95), and eagerness to take chances (-0.6). This pilot study demonstrated evidence of initial content validity of the PR-PIADS. Future research is required before using this tool with greater confidence to address the construct validity and reliability that are also critical to a successful cultural adaptation.

  11. Left ventricular diastolic filling with an implantable ventricular assist device: beat to beat variability with overall improvement

    Science.gov (United States)

    Nakatani, S.; Thomas, J. D.; Vandervoort, P. M.; Zhou, J.; Greenberg, N. L.; Savage, R. M.; McCarthy, P. M.

    1997-01-01

    OBJECTIVES: We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling. BACKGROUND: Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance. METHODS: Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation. RESULTS: Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables. CONCLUSIONS: With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but overall diastolic filling tended to normalize with an increase of atrial contribution to the filling. Because of the variable nature of the transmitral flow pattern with the assist device, the timing of the device cycle must be considered when inferring diastolic function from transmitral flow pattern.

  12. Management issues during HeartWare left ventricular assist device implantation and the role of transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Sanjay Orathi Patangi

    2013-01-01

    Full Text Available Left ventricular assist devices (LVAD are increasingly used for mechanical circulatory support of patients with severe heart failure, primarily as a bridge to heart transplantation. Transesophageal echocardiography (TEE plays a major role in the clinical decision making during insertion of the devices and in the post-operative management of these patients. The detection of structural and device-related mechanical abnormalities is critical for optimal functioning of assist device. In this review article, we describe the usefulness of TEE for optimal perioperative management of patients presenting for HeartWare LVAD insertion.

  13. Design and User Evaluation of a Wheelchair Mounted Robotic Assisted Transfer Device

    Directory of Open Access Journals (Sweden)

    Garrett G. Grindle

    2015-01-01

    Full Text Available Purpose. The aim of this study is to describe the robotic assisted transfer device (RATD and an initial focus group evaluation by end users. The purpose of the device is to aid in the transfers of people with disabilities to and from their electric powered wheelchair (EPW onto other surfaces. The device can be used for both stand-pivot transfers and fully dependent transfers, where the person being transferred is in a sling and weight is fully on the robot. The RATD is fixed to an EPW to allow for its use in community settings. Method. A functional prototype of the RATD was designed and fabricated. The prototype was presented to a group of 16 end users and feedback on the device was obtained via a survey and group discussion. Results. Thirteen out of sixteen (83% participants agreed that it was important to develop this type of technology. They also indicated that user, caregiver, and robotic controls were important features to be included in the device. Conclusions. Participants in this study suggested that they would be accepting the use of robotic technology for transfers and a majority did not feel that they would be embarrassed to use this technology.

  14. Shape optimization of pulsatile ventricular assist devices using FSI to minimize thrombotic risk

    Science.gov (United States)

    Long, C. C.; Marsden, A. L.; Bazilevs, Y.

    2014-10-01

    In this paper we perform shape optimization of a pediatric pulsatile ventricular assist device (PVAD). The device simulation is carried out using fluid-structure interaction (FSI) modeling techniques within a computational framework that combines FEM for fluid mechanics and isogeometric analysis for structural mechanics modeling. The PVAD FSI simulations are performed under realistic conditions (i.e., flow speeds, pressure levels, boundary conditions, etc.), and account for the interaction of air, blood, and a thin structural membrane separating the two fluid subdomains. The shape optimization study is designed to reduce thrombotic risk, a major clinical problem in PVADs. Thrombotic risk is quantified in terms of particle residence time in the device blood chamber. Methods to compute particle residence time in the context of moving spatial domains are presented in a companion paper published in the same issue (Comput Mech, doi: 10.1007/s00466-013-0931-y, 2013). The surrogate management framework, a derivative-free pattern search optimization method that relies on surrogates for increased efficiency, is employed in this work. For the optimization study shown here, particle residence time is used to define a suitable cost or objective function, while four adjustable design optimization parameters are used to define the device geometry. The FSI-based optimization framework is implemented in a parallel computing environment, and deployed with minimal user intervention. Using five SEARCH/ POLL steps the optimization scheme identifies a PVAD design with significantly better throughput efficiency than the original device.

  15. The Ventricular Assist Device in the Life of the Child: A Phenomenological Pediatric Study.

    Science.gov (United States)

    van Manen, Michael A

    2017-05-01

    What is it like for a child to live with an artificial heart? The use of some medical therapies in children requires developmental considerations, is associated with psychosocial consequences, and calls for ethical sensitivities. A critical case is the ventricular assist device (VAD), a mechanical pump used to support the functioning of a failing heart. As a pediatric therapy, the device can be used as a temporary solution for poor heart function, a bridge to transplantation or recovery, or as a destination therapy. While the mechanical-technical operation of the VAD is well understood, the clinical-technical aspects of young people living with this device are largely unexplored. Drawing on interviews of school-aged children, the aim of this phenomenological study is to explore how a VAD may structure or condition a child's meaningful experience of their world outside the hospital. The driveline of an implanted VAD is the peripheral attachment, extruding through the skin to connect the controller-power supply. The materiality of the device may be interruptive, restrictive, and disturbing to the psycho-physical being and sense of self-identity of the child as a child. And while a child equipped with a VAD is not necessarily conspicuous among other children, the child may experience the device as an exposing presence, while living with the worry of a caregiver who takes on the role not simply of parent but of watchful health professional. A phenomenological understanding of the VAD should assist parents and caregiving health professionals knowing how to deal with specific issues arising in the life of the VAD child.

  16. Pediatric Acquired von Willebrand Disease With Berlin Heart Excor Ventricular Assist Device Support.

    Science.gov (United States)

    Gossai, Nathan; Brown, Nicholas M; Ameduri, Rebecca; Zantek, Nicole D; Louis, James St; Steiner, Marie E

    2016-09-01

    The balance of hemostasis and anticoagulation is a concern for patients dependent upon ventricular assist devices (VADs). Bleeding is a common complication with both short- and long-term use of these devices. A better understanding of the risk factors and etiologies of bleeding associated with these devices is needed and could improve the overall results. We sought to determine the relationship of mechanical circulatory assist device use with acquired von Willebrand disease (avWD) in children. Data were analyzed retrospectively via review of the medical record of 19 consecutive patients who were supported with the Berlin EXCOR VAD for greater than 24 hours. Laboratory testing for avWD was performed at the discretion of the clinical team, often in association with clinical bleeding. Of 19 pediatric patients, 10 (52.6%) had laboratory testing consistent with avWD. Median time to detection of avWD was 35 days postimplantation of device (range 0-310 days). Both minor mucosal bleeding and bleeding requiring intervention were highly prevalent in patients in whom avWD was identified (10/10 [100%] and 7/10 [70%]). The mean age of all patients was 3.3 years, but patients found to have avWD tended to be older (mean 5.3 years) and supported with larger volume VADs. This experience demonstrates a high prevalence of avWD following EXCOR implantation. Bleeding, older age, and larger VAD size may be associated with avWD. These results should stimulate critical evaluation of individualized anticoagulation regimens in pediatric VAD patients. © The Author(s) 2016.

  17. In vivo quantification of intraventricular flow during left ventricular assist device support

    Science.gov (United States)

    Vu, Vi; Wong, Kin; Del Alamo, Juan; Aguilo, Pablo M. L.; May-Newman, Karen; Department of Bioengineering, San Diego State University Collaboration; Department of Mechanical; Aerospace Engineering, University of California San Diego Collaboration; Mechanical Assist Device Program, Sharp Memorial Hospital Collaboration

    2014-11-01

    Left ventricular assist devices (LVADs) are mechanical pumps that are surgically connected to the left ventricle (LV) and aorta to increase aortic flow and end-organ perfusion. Clinical studies have demonstrated that LVADs improve patient health and quality of life and significantly reduce the mortality of cardiac failure. However, In the presence of left ventricular assisted devices (LVAD), abnormal flow patterns and stagnation regions are often linked to thrombosis. The aim of our study is to evaluate the flow patterns in the left ventricle of the LVAD-assisted heart, with a focus on alterations in vortex development and blood stasis. To this aim, we applied color Doppler echocardiography to measure 2D, time resolved velocity fields in patients before and after implantation of LVADs. In agreement with our previous in vitro studies (Wong et al., Journal of Biomechanics 47, 2014), LVAD implantation resulted in decreased flow velocities and increased blood residence time near the outflow tract. The variation of residence time changes with LVAD operational speed was characterized for each patient.

  18. Remission of chronic anthracycline-induced heart failure with support from a continuous-flow left ventricular assist device.

    Science.gov (United States)

    Khan, Nadeem; Husain, Syed Arman; Husain, Syed Iman; Khalaf, Natalia; George, Joggy; Raissi, Farshad; Segura, Ana Maria; Kar, Biswajit; Bogaev, Roberta C; Frazier, O H

    2012-01-01

    We report the case of a patient who had chronic anthracycline-induced cardiomyopathy that was reversed after treatment with a left ventricular assist device. A 29-year-old woman had undergone anthracycline-based chemotherapy as a teenager in 1991 and 1992 and received a diagnosis of dilated cardiomyopathy 10 years later. Optimal medical therapy had initially controlled the symptoms of heart failure. However, in June 2006, the symptoms worsened to New York Heart Association functional class IV status. We implanted a continuous-flow left ventricular assist device as a bridge to cardiac transplantation; of note, a left ventricular core biopsy at that time showed no replacement fibrosis. The patient's clinical status improved thereafter, enabling left ventricular assist device ex-plantation after 17 months. To our knowledge, this is the first report of the use of left ventricular assist device support to reverse chronic anthracycline-induced heart failure.

  19. Experimental studies on the human gait using a tethered pelvic assist device (T-PAD).

    Science.gov (United States)

    Vashista, Vineet; Mustafa, S K; Agrawal, Sunil K

    2011-01-01

    This paper presents the prototype of a novel tethered pelvic assist device (T-PAD). This is a purely passive device, consisting of a set of elastic tethers with one end attached to a hip brace worn by a subject walking on a treadmill, and the other end attached to a fixed frame surrounding the subject. T-PAD offers the flexibility of varying the assistance required on the pelvis by changing the configuration of the tether attachment locations, number of tethers and tether elasticity. Experimental studies were conducted using a full and a partial pelvic constraint configuration of T-PAD, with varying tether elasticity. The studies were aimed at observing the effect of T-PAD on the human gait. Results show that T-PAD reduced the range-of-motion for the pelvic angles with increase of tether elasticity. However, it had mixed effects on the range-of-motion of the hip angles, but negligible effect on the knee and ankle joint angles. Overall, T-PAD shows potential as a low-cost pelvic support device with pelvic motion control capabilities, and can work in tandem with existing gait trainers. © 2011 IEEE

  20. [Rise of the machines? Left ventricular assist devices for treatment of severe heart failure].

    Science.gov (United States)

    Ujeyl, A; Krüger, M

    2015-11-01

    The use of left ventricular assist devices (LVAD) as a treatment for severe heart failure has gained momentum in recent years. Even at this stage the number of worldwide LVAD implantations far exceeds the volume of heart transplantations in view of the chronic shortage of donor organs. Third generation continuous flow assist devices have helped to improve survival, quality of life and symptom burden of heart failure patients in comparison to a regimen of optimal medication management. Alongside bridging to transplantation, destination therapy has become an established strategy of LVAD implantation. A careful patient selection process is crucial for a good clinical outcome after device implantation and risk assessment for postoperative right ventricular failure is of particular importance in this context. The rate of hospitalization during LVAD support is still high, despite the step-wise attempts to widen the indications to less severely ill heart failure patients. An effective perioperative and postoperative management will help to lower the incidence of complications (e.g. bleeding, infections, thromboembolic events and right ventricular failure) and to improve the encouraging results of mechanical circulatory support.

  1. Understanding the Provision of Assistive Mobility and Daily Living Devices and Service Delivery to Veterans After Stroke.

    Science.gov (United States)

    Kairalla, John A; Winkler, Sandra L; Feng, Hua

    2016-01-01

    The objective of this study was to determine whether facility-level, structural factors affect the provision of assistive devices and services. A retrospective design was used. Activities of daily living and mobility-related devices were categorized into 11 types. Logistic regression models were performed for each type of device, controlling for patient-level and facility-level covariates. Non-veteran-level factors significantly affect the provision of assistive devices, even after covariate adjustment. Increased rehabilitation clinician staffing by 1 full-time equivalent position was associated with increased provision odds of 1%-5% for 5 of 11 types of devices. Lower facility complexity was significantly associated with increased provision odds of 35%-59% for 3 types of devices and with decreased provision odds of 16%-69% for 3 types of devices. System-level factors, in addition to patient need, significantly affect the provision of assistive devices. Provision guidelines could assist clinicians in making decisions about device provision. Copyright © 2016 by the American Occupational Therapy Association, Inc.

  2. Impact of pacing modality and biventricular pacing on cardiac output and coronary conduit flow in the post-cardiotomy patient.

    LENUS (Irish Health Repository)

    Healy, David G

    2012-02-03

    We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing first time elective coronary artery bypass grafting who required pacing following surgery were recruited. Comparison of cardiac output and coronary conduit flow was performed between VVI and DDD pacing with a single right ventricular lead and biventricular pacing lead placement. Cardiac output was measured using arterial pulse waveform analysis while conduit flow was measured using ultrasonic transit time methodology. Cardiac output was greatest with DDD pacing using right ventricular lead placement only [DDD-univentricular 5.42 l (0.7), DDD-biventricular 5.33 l (0.8), VVI-univentricular 4.71 l (0.8), VVI-biventricular 4.68 l (0.6)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.023) and VVI-biventricular pacing (P=0.001) but there was no significant advantage to DDD-biventricular pacing (P=0.45). In relation to coronary conduit flow, DDD pacing again had the highest flow [DDD-univentricular 55 ml\\/min (24), DDD-biventricular 52 ml\\/min (25), VVI-univentricular 47 ml\\/min (23), VVI-biventricular 50 ml\\/min (26)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.006) pacing but not significantly different to VVI-biventricular pacing (P=0.109) or DDD-biventricular pacing (P=0.171). Pacing with a DDD modality offers the optimal coronary conduit flow by maximising cardiac output. Biventricular lead placement offered no significant benefit to coronary conduit flow or cardiac output.

  3. Cardiac resynchronization therapy or atrio-biventricular pacing-what should it be called?

    Science.gov (United States)

    Cleland, John G F; Nasir, Mansour; Tageldien, Ahmed

    2007-02-01

    Reduced cardiac efficiency caused by suboptimal synchronization of the heart's normal contraction might contribute to the development of or exacerbate heart failure. Conceptually and in practice cardiac dyssynchrony is complex. Recent studies have shown that atrio-biventricular pacing can improve cardiac synchrony in many patients and improve cardiac function, symptoms and exercise capacity, and reduce morbidity and mortality substantially. Randomized controlled trials, however, indicate that the severity of cardiac dyssynchrony, as conventionally measured, is a poor guide to treatment benefit and that correction of dyssynchrony accounts for only part of the benefit of atrio-biventricular pacing. Although some of the benefits of atrio-biventricular pacing might be mediated by cardiac resynchronization, much of the benefit could be mediated by mechanisms that are as yet unknown. Withholding atrio-biventricular pacing in patients who do not exhibit cardiac dyssynchrony on imaging but otherwise fulfil the entry criteria used in randomized controlled trials of this therapy could be unwise. Here, we examine the evidence that cardiac resynchronization is indeed the mechanism by which atrio-biventricular pacing exerts its effects.

  4. The Role of Subjective Well-Being in Co-Designing Open-Design Assistive Devices; design case study

    NARCIS (Netherlands)

    De Couvreur, L.; Dejonghe, W.; Detand, J.; Goossens, R.

    2013-01-01

    In this paper we explore the role of subjective well-being within the process of making together a personalized assistive device. Through a process of social product adaptation, assistive artifacts become part of occupational therapy and co-evolve with clients. Personal digital fabrication tools

  5. Hydraulic and hemodynamic performance of a minimally invasive intra-arterial right ventricular assist device.

    Science.gov (United States)

    Hsu, Po-Lin; Graefe, Roland; Boehning, Fiete; Wu, Chen; Parker, Jack; Autschbach, Rüdiger; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2014-09-01

    Right ventricular assistance is still in the early phase of development compared to left ventricular assist device (LVAD) technology. In order to provide flexible pulmonary support and potentially reduce the known complications, we propose a minimally invasive right ventricular assist device (MIRVAD), located in the pulmonary artery (PA) and operating in series with the right ventricle (RV). The MIRVAD is an intra-arterial rotary blood pump containing a single axial impeller, which is not enclosed by a rigid housing but stent-fixed within the vessel. The impeller geometry has been designed with the assistance of analytical methods and computational fluid dynamics (CFD). The hydraulic performance of the impeller was evaluated experimentally with a customized test setup using blood synthetic medium (HES). The blade-tip clearance (BTC) was varied between 0.25-4.25 mm to evaluate the effect of different PA sizes on impeller performance. Furthermore, the Langrangian particle-tracking method was used to estimate the level of hemolysis and generate numerical blood damage indexes.The impeller design generated 25.6 mmHg for flow rates of 5 lpm at a speed of 6,000 rpm at the baseline condition, capable of providing sufficient support for the RV. The BTC presented a significant effect on the static pressure generation and the efficiency, but the operational range is suitable for most vessel sizes. The numerical results demonstrated a low risk of blood damage at the design point (mean Lagrangian damage index 2.6*10(-7)). The preliminary results have encouraged further impeller optimization and development of the MIRVAD.

  6. [The intracardial hemopump. A new technique of left ventricle assist device].

    Science.gov (United States)

    Loisance, D; Dubois-Randé, J L; Deleuze, P; Rosenval, O; Zelinski, R; Shiiya, N; Geschwind, H

    1990-12-01

    A new left ventricular assist device consisting of a canula containing a turbine introduced by retrograde catheterisation was evaluated in the prevention of complications in 9 patients undergoing high risk coronary angioplasty. The good clinical and hemodynamic status during and after coronary dilatation confirmed the system's innocuity and its efficacy each time it could be correctly positioned in the ventricle (6 patients). These extremely encouraging preliminary results suggest that an additional simplification but reducing the size of the canula and increasing turbine flow, allowing percutaneously introduction would constitute a significant development.

  7. Manual material handling advice and assistive devices for preventing and treating back pain in workers.

    Science.gov (United States)

    Verbeek, Jos H; Martimo, Kari-Pekka; Karppinen, Jaro; Kuijer, P Paul Fm; Viikari-Juntura, Eira; Takala, Esa-Pekka

    2011-06-15

    Training and the provision of assistive devices are considered major interventions to prevent back pain and its related disability among workers exposed to manual material handling (MMH). To determine the effectiveness of MMH advice and training and the provision of assistive devices in preventing and treating back pain. We searched CENTRAL (The Cochrane Library 2011, issue 1), MEDLINE, EMBASE, CINAHL, Nioshtic, CISdoc, Science Citation Index, and PsychLIT to February 2011. We included randomised controlled trials (RCT) and cohort studies with a concurrent control group that were aimed at changing human behaviour in MMH and measured back pain, back pain-related disability or sickness absence. Two authors independently extracted the data and assessed the risk of bias using the criteria recommended by the Cochrane Back Review Group for RCTs and MINORS for the cohort studies.We based the results and conclusions on the analysis of RCTs only. We compared these with the results from cohort studies. We included nine RCTs (20,101 employees) and nine cohort studies (1280 employees) on the prevention of back pain in this updated review. Studies compared training to no intervention (4), professional education (2), a video (3), use of a back belt (3) or exercise (2). Other studies compared training plus lifting aids to no intervention (3) and to training only (1). The intensity of training ranged from a single educational session to very extensive personal biofeedback.Six RCTs had a high risk of bias.None of the included studies showed evidence of a preventive effect of training on back pain.There was moderate quality evidence from seven RCTs (19,317 employees) that those who received training reported levels of back pain similar to those who received no intervention, with an odds ratio of 1.17 (95% confidence intervals (CI) 0.68 to 2.02) or minor advice (video), with a relative risk of 0.93 (95% CI 0.69 to 1.25). Confidence intervals around the effect estimates were still

  8. Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System.

    Science.gov (United States)

    Ohnishi, Kengo; Saito, Yukio; Oshima, Toru; Higashihara, Takanori

    2013-01-01

    This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions.

  9. Severe hemolytic anemia caused by the NIPRO extracorporeal left ventricular assist device.

    Science.gov (United States)

    Shibasaki, Ikuko; Kuwata, Toshiyuki; Tsuchiya, Go; Ogawa, Hironaga; Yamada, Yasuyuki; Toyoda, Shigeru; Inoue, Teruo; Fukuda, Hirotsugu

    2017-04-01

    A 56-year-old woman with dilated cardiomyopathy underwent mitral and tricuspid annuloplasty, and simultaneous deployment of an extracorporeal left ventricular assist device (LVAD). Subsequently, she developed hemolytic anemia. Although the LVAD system was repeatedly exchanged and the mitral annular ring was removed, her hemolytic anemia did not improve. Finally, the NIPRO LVAD was replaced with Gyro Pump ® , and her anemia was ameliorated. It appears important to consider the possibility of hemolytic anemia as a LVAD-related complication, although it would be rare.

  10. Vasodilatory Shock After Ventricular Assist Device Placement: A Bench to Bedside Review.

    Science.gov (United States)

    Baer, John; Stoops, Shea; Flynn, Brigid

    2016-01-01

    With more than 2000 ventricular assist devices (VAD) placed annually in the United States, understanding postoperative management is important. One of the most common postoperative morbidities encountered with VAD implantation is vasodilatory shock. The mechanisms for this phenomenon are numerous and include cellular and hormonal aberrancies unique to the VAD recipient. Management of vasodilatory shock in VAD patients needs to be undertaken with an understanding of the side effects associated with each treatment, especially the effects on the right ventricle and pulmonary vasculature. This article focuses on the incidence, the pathogenesis, the consequences, and the management of vasodilatory shock in the postoperative VAD patient. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Experience with left ventricular assist device usage in the treatment of end-stage heart failure

    Directory of Open Access Journals (Sweden)

    B.M. Todurov

    2017-06-01

    Full Text Available Heart failure potentially developing in most of heart diseases is a progressive process associated with high morbidity and mortality. Almost 3/4 of patients die within five years after first hospitalization because of heart failure. The main treatment for patients with terminal heart failure is heart transplantation. Left ventricular assist device is a main alternative to heart transplantation. We present case of long-term mechanical support applied in patients with heart failure class IV NYHA, refractory to medical therapy. Long-term implantation of mechanical heart support system may serve as an effective bridge to heart transplantation in patients with advanced congestive heart failure.

  12. A novel junction-assisted programming scheme for Si-nanocrystal memory devices with improved performance

    Science.gov (United States)

    Jiang, Dandan; Huo, Zongliang; Zhang, Manhong; Jin, Lin; Bai, Jie; Yu, Zhaoan; Liu, Jing; Wang, Qin; Yang, Xiaonan; Wang, Yong; Zhang, Bo; Chen, Junning; Liu, Ming

    2011-11-01

    A novel drain-junction-assisted hot electron programming scheme has been proposed for Si nanocrystal memory devices. Different from the conventional channel hot electron (CHE) injection, two electron injection paths are responsible for the proposed scheme. Experimental results show that the new scheme has a nearly 1 V memory window increase and almost 300 times faster programming speed rather than the conventional CHE method. Meanwhile, improved data retention and endurance characteristics have also been achieved with the enlarged memory window, which is mainly due to less tunnel oxide degradation during the program/erase cycling. Therefore, the new scheme is shown to be more promising for Si nanocrystal memory application.

  13. Pimobendan in Chronic Right Heart Failure in a Left Ventricular Assist Device Patient

    Science.gov (United States)

    Kreibich, Maximilian; Berchtold-Herz, Michael; Beyersdorf, Friedhelm; Trummer, Georg

    2016-01-01

    We report the case of a 76-year-old patient who developed chronic right heart failure 1 year after left ventricular assist device implantation due to ischemic cardiomyopathy. Initial recompensation was achieved through dobutamin, sildenafil, and levosimendan treatment. Yet, discharge was successful only after the off-label use of the oral calcium sensitizer pimobendan. Ten months after discharge, the patient presents with no clinical signs of right heart failure and significantly improved right heart function without any impairment in quality of life. PMID:28018821

  14. Radical Cystectomy with Ileal Conduit Urinary Diversion in a Patient with a Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Joseph J. Pariser

    2015-01-01

    Full Text Available Left ventricular assist device (LVAD is an option for the surgical management of severe heart failure, and radical cystectomy remains the standard of care for muscle-invasive bladder cancer. Given a complicated population in terms of comorbidities and management for patients with an LVAD, there is little experience with major urologic procedures, which require balancing the benefits of surgery with considerable perioperative risks. We report our experience performing the first radical cystectomy with ileal conduit in a patient with an LVAD and muscle-invasive bladder cancer.

  15. Repair of pectus excavatum during HeartMate II left ventricular assist device placement.

    Science.gov (United States)

    Tchantchaleishvili, Vakhtang; Massey, Howard Todd

    2016-01-01

    Pectus excavatum deformity often remains clinically asymptomatic even in cases of a severely diminished thoracic volume and frequently remains uncorrected. In the patient population that requires left ventricular assist device (LVAD) placement, a diminished thoracic volume can be problematic and lead to significant challenges in pump and outflow cannula positioning. Here we present a case of pectus excavatum correction during LVAD placement to show that this deformity can be successfully addressed with minimal, if any, additional operative risk at the time of LVAD implant. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  16. [Rehabilitation standards for follow-up treatment and rehabilitation of patients with ventricular assist device (VAD)].

    Science.gov (United States)

    Willemsen, Detlev; Cordes, C; Bjarnason-Wehrens, B; Knoglinger, E; Langheim, E; Marx, R; Reiss, N; Schmidt, T; Workowski, A; Bartsch, P; Baumbach, C; Bongarth, C; Phillips, H; Radke, R; Riedel, M; Schmidt, S; Skobel, E; Toussaint, C; Glatz, J

    2016-03-01

    The increasing use of ventricular assist devices (VADs) in terminal heart failure patients provides new challenges to cardiac rehabilitation physicians. Structured cardiac rehabilitation strategies are still poorly implemented for this special patient group. Clear guidance and more evidence for optimal modalities are needed. Thereby, attention has to be paid to specific aspects, such as psychological and social support and education (e.g., device management, INR self-management, drive-line care, and medication).In Germany, the post-implant treatment and rehabilitation of VAD Patients working group was founded in 2012. This working group has developed clear recommendations for the rehabilitation of VAD patients according to the available literature. All facets of VAD patients' rehabilitation are covered. The present paper is unique in Europe and represents a milestone to overcome the heterogeneity of VAD patient rehabilitation.

  17. iPhone in the Management of the Berlin Heart EXCOR Ventricular Assist Device.

    Science.gov (United States)

    Badheka, Aditya; Allareddy, Veerajalandhar

    Berlin Heart Inc. EXCOR is an extracorporeal pneumatically pulsatile ventricular assist device approved for use in pediatric age group since 2011 in the United States. It is a well-established life-saving therapy for the bridge to heart transplant or to provide circulatory support in a transplanted patient. The most commonly reported problem was "membrane defect" in a postmarketing major device reporting. In general, the filling and emptying of the pump can be easily visualized, but the interobserver variability exist. In this first novel report, we used the iPhone slow motion video to quantify and compare the differences in filling and emptying that positively impacted the management of the Berlin Heart. This is an initial exploratory concept that will need further studies to validate this bedside tool.

  18. Use of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

    Science.gov (United States)

    Saeed, Diyar; Horvath, David J; Massiello, Alex L; Ootaki, Yoshio; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

    2010-02-01

    Our aim was to evaluate the potential use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. The DexAide titanium stator was replaced by a zirconia stator in several blood pump builds, without changing the remaining pump hardware components. In vitro pump performance and efficiency were evaluated at a predetermined pump speed and flow. Motor power consumption decreased by 20%, and DexAide battery life was extended to over 12 h on two fully charged batteries. The zirconia stator was also successfully evaluated in a severe start/stop test pre- and postexposure of the zirconia to accelerated simulated biologic aging. This study's outcomes indicated the advantages of zirconia as an alternate journal bearing material for the DexAide device.

  19. Safety and Feasibility of Laparoscopic Abdominal Surgery in Patients With Mechanical Circulatory Assist Devices.

    Science.gov (United States)

    Ashfaq, Awais; Chapital, Alyssa B; Johnson, Daniel J; Staley, Linda L; Arabia, Francisco A; Harold, Kristi L

    2016-10-01

    Objectives Increasing number of mechanical circulatory assist devices (MCADs) are being placed in heart failure patients. Morbidity from device placement is high and the outcome of patients who require noncardiac surgery after, is unclear. As laparoscopic interventions are associated with decreased morbidity, we examined the impact of such procedures in these patients. Methods A retrospective review was conducted on 302 patients who underwent MCAD placement from 2005 to 2012. All laparoscopic abdominal surgeries were included and impact on postoperative morbidity and mortality studied. Results Ten out of 16 procedures were laparoscopic with 1 conversion to open. Seven patients had a HeartMate II, 2 had Total Artificial Hearts, and 1 had CentriMag. Four patients had devices for ischemic cardiomyopathy and 6 cases were emergent. Surgeries included 6 laparoscopic cholecystectomies, 2 exploratory laparoscopies, 1 laparoscopic colostomy takedown, and 1 laparoscopic ventral hernia repair with mesh. Median age of the patients was 63 years (range, 29-79 years). Median operative time was 123 minutes (range, 30-380 minutes). Five of 10 patients were on preoperative anticoagulation with average intraoperative blood loss of 150 mL (range, 20-700 mL). There were 3 postoperative complications; acute respiratory failure, acute kidney injury and multisystem organ failure resulting in death not related to the surgical procedure. Conclusion The need for noncardiac surgery in post-MCAD patients is increasing due to limited donors and due to more durable and longer support from newer generation assist devices. While surgery should be approached with caution in this high-risk group, laparoscopic surgery appears to be a safe and successful treatment option. © The Author(s) 2016.

  20. Assessment of thermal dissipation effects in a ventricular assist device - biomed 2013.

    Science.gov (United States)

    Kailasan, Arunvel; Untaroiu, Alexandrina; Pravin, Swapnil; Wood, Houston G

    2013-01-01

    The heat generated during normal operation of an implantable Left Ventricular Assist Device (LVAD) can have a deleterious effect on the surrounding tissue as well as the blood flowing through the device. This effect is often overlooked and might also result in heart pump failure. Therefore, for a comprehensive design evaluation it is essential to accurately model the thermal dissipation in a LVAD system to ensure safety and device reliability. The LifeFlow artificial heart pump is a magnetically suspended axial flow LVAD in which the motor as well as the suspension system are the primary sources for heat generation. The objective of this study is to perform a thorough thermal analysis of the device using a combination of heat transfer equations, 3D-Finite Element analysis and 3D-CFD modeling. Particularly, the effects of heat generated on blood passing through the device due to the motor, magnetic suspension system and housing are studied. Conduction and convection effects due to the above contributors are analyzed. In addition, temperature distributions are estimated for different flow rates and pressure differentials. As a result of this study, it can be inferred if nominal operation of the LifeFlow LVAD would have any significant thermal effects on blood passing through the device. Results show that there is a 2.2°C temperature increase in the magnetic suspension system during nominal operation, while the blood temperature is increasing by 1.6°C. Assessment of thermal effects is crucial since high temperature exposure of blood could ultimately affect the patient whose systemic circulation is supported by the LVAD.

  1. Biventricular / Left Ventricular Pacing in Hypertrophic Obstructive Cardiomyopathy: An Overview

    Directory of Open Access Journals (Sweden)

    Radu Vatasescu, MD

    2012-05-01

    Full Text Available Hypertrophic cardiomyopathy (HCM is an autosomal dominant inherited genetic disease characterized by compensatory pathological left ventricle (LV hypertrophy due to sarcomere dysfunction. In an important proportion of patients with HCM, the site and extent of cardiac hypertrophy results in severe obstruction to LV outflow tract (LVOT, contributing to disabling symptoms and increasing the risk of sudden cardiac death (SCD. In patients with progressive and/or refractory symptoms despite optimal pharmacological treatment, invasive therapies that diminish or abolish LVOT obstruction relieve heart failure-related symptoms, improve quality of life and could be associated with long-term survival similar to that observed in the general population. The gold standard in this respect is surgical septal myectomy, which might be supplementary associated with a reduction in SCD. Percutaneous techniques, particularly alcohol septal ablation (ASA and more recently radiofrequency (RF septal ablation, can achieve LVOT gradient reduction and symptomatic benefit in a large proportion of HOCM patients at the cost of a supposedly limited septal myocardial necrosis and a 10-20% risk of chronic atrioventricular block. After an initial period of enthusiasm, standard DDD pacing failed to show in randomized trials significant LVOT gradient reductions and objective improvement in exercise capacity. However, case reports and recent small pilot studies suggested that atrial synchronous LV or biventricular (biV pacing significantly reduce LVOT obstruction and improve symptoms (acutely as well as long-term in a large proportion of severely symptomatic HOCM patients not suitable to other gradient reduction therapies. Moreover, biV/LV pacing in HOCM seems to be associated with significant LV reverse remodelling.

  2. Development of a power-assisted lifting device for construction and periodic inspection

    International Nuclear Information System (INIS)

    Hayatsu, M.; Yamada, M.; Takasu, H.; Tagawa, Y.; Kajiwara, K.

    2001-01-01

    This study focuses on the control system design and control performance of a power-assisted lifting device. The device consists of several electric chain-blocks, each controlled by force sensors and a CPU. The mechanism is as follows: (1) Force sensors detect any chain tension changes (by human force), (2) The CPU calculates the required output, (3) Electric chain-blocks move the object in the intended direction. The feature of this device is that it does not require any information related to the suspension points of the electric chain-blocks. The controller was designed using the H method, which considers disturbances and aims to provide robust stability under the operation conditions of construction verified through experiments using a 700 kg steel dummy mass (control object) suspended by four electric chain-blocks. In the experiments, the controller, which was designed using the H method, was compared to the PI controller method, and the effectiveness of the H controller was proven. A control object could be moved, translated, and rotated by human force (of less than 10 kg). Positioning performance errors were suppressed to less than 0.5 mm, and operation time was reduced by about 50%. This device will improve working efficiency and rationalize lifting operations in nuclear power plants. (author)

  3. Management of three cardiogenic pulmonary edemas occurring in a patient scheduled for left ventricular assist device implantation: indicators for determining left ventricular assist device pump speed.

    Science.gov (United States)

    Toyama, Hiroaki; Takei, Yusuke; Saito, Kazutomo; Ota, Takahisa; Kurotaki, Kenji; Ejima, Yutaka; Matsuura, Takeshi; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yamauchi, Masanori

    2016-08-01

    A male patient with Marfan syndrome underwent aortic root replacement and developed left ventricular (LV) failure. Four years later, he underwent aortic arch and aortic valve replacement. Thereafter, his LV failure progressed, and cardiogenic pulmonary edema (CPE) appeared, which we treated with extracorporeal LV assist device (LVAD) placement. Three months later, the patient developed aspiration pneumonia, which caused hyperdynamic right ventricle (RV) and CPE. We treated by changing his pneumatic LVAD to a high-flow centrifugal pump. A month later, he underwent thoracoabdominal aortic replacement. After four weeks, he developed septic thrombosis and LVAD failure, which caused CPE. We treated with LVAD circuit replacement and an additional membrane oxygenator. Four months later, he underwent DuraHeart(®) implantation. During this course, pulmonary artery wedge pressure (PAWP) varied markedly. Additionally, systolic pulmonary artery pressure (sPAP), left atrial diameter (LAD), RV end-diastolic diameter (RVEDD) and estimated RV systolic pressure (esRVP) changed with PAWP changes. In this patient, LV failure and hyperdynamic RV caused the CPEs, which we treated by adjusting the LVAD output to the RV output. Determining LVAD output, RV function and LV end-diastolic diameter are typically referred, and PAWP, LAD, RVEDD, and sPAP could be also referred.

  4. Feasibility of cell transplantation with a left ventricular assist device to improve the success rate of left ventricular assist device removal: the first experiment.

    Science.gov (United States)

    Mizuno, Tomohiro

    2011-01-01

    Left ventricular assist devices (LVADs) greatly support heart recovery, but recurrent heart failure after LVAD removal limits their use as 'a bridge to recovery'. The combination of LVADs and cell transplantation (CTx) is expected to be effective to improve the success rate of LVAD removal. We investigated the feasibility of combined CTx therapy and LVAD support with a new heterotopic rat heart-lung transplantation model that could simulate LVAD support and LVAD removal. The heart and both lungs of a rat were heterotopically transplanted, and the heart was kept unloaded for two weeks. The heart was then reloaded for two weeks (LVAD group). Syngenic smooth muscle cells were transplanted into the hearts that had been unloaded for a week, and the hearts were kept unloaded for another week and then reloaded (CT-LVAD group). In the unloaded state, CTx could reduce the left ventricle (LV) volume more effectively than LVAD therapy alone (P<0.01) and maintain the LV volume even after the hearts were reloaded (P<0.01). The results suggest that CTx with LVAD support can prevent recurrent LV dilation after LVAD removal and improve the success rate of LVAD removal.

  5. Octreotide for the Management of Gastrointestinal Bleeding in a Patient with a HeartWare Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Geetanjali Dang

    2014-01-01

    Full Text Available HeartWare is a third generation left ventricular assist device (LVAD, widely used for the management of advanced heart failure patients. These devices are frequently associated with a significant risk of gastrointestinal (GI bleeding. The data for the management of patients with LVAD presenting with GI bleeding is limited. We describe a 56-year-old lady, recipient of a HeartWare device, who experienced recurrent GI bleeding and was successfully managed with subcutaneous (SC formulations of octreotide.

  6. Psychological distress in patients with a left ventricular assist device and their partners

    DEFF Research Database (Denmark)

    Brouwers, Corline; Denollet, Johan; Caliskan, Kadir

    2015-01-01

    Background:Left ventricular assist device (LVAD) therapy is increasingly used in patients with advanced heart failure, and may have a significant psychological impact on both patients and their partners. Hence, we examined the distress levels of LVAD patients and their partners.Methods:Anxiety, d......Background:Left ventricular assist device (LVAD) therapy is increasingly used in patients with advanced heart failure, and may have a significant psychological impact on both patients and their partners. Hence, we examined the distress levels of LVAD patients and their partners.......Methods:Anxiety, depression and post-traumatic stress disorder (PTSD) were assessed at 3-4 weeks after implantation, and at 3 and 6 months follow-up in 33 LVAD patients (73% men; mean age=54±10 years) and 33 partners (27% men; mean age=54±11 years).Results:The prevalence of anxiety in LVAD partners was significantly higher...... correction for age, gender and clinical covariates. However, after correction for Type D personality and the use of psychotropic medication the LVAD partners showed significantly higher anxiety (F=6.95, p=0.01) and depression (F=3.94, p=0.04) scores over time compared to LVAD patients...

  7. Haptic cue control of an MR gear shifting assistance device via Preisach hysteresis linearization

    Science.gov (United States)

    Han, Young-Min; Choi, Seung-Bok; Chung, Jye Ung; Kim, Soomin

    2015-04-01

    This paper proposes a driver assistance device to notify vehicle drivers an optimal gear shifting timing considering fuel consumption in manual transmission vehicles. The haptic cue function of the proposed gear shifting assistance device is utilizing magnetorheological (MR) clutch mechanism as haptic interface between driver and vehicle. The shear stress level and hysteretic behavior of the employed MR fluid are experimentally observed and identified with the Preisach model. A rotary type clutch mechanism is designed and manufactured with electromagnetic circuit and its transmission torque level is experimentally evaluated according to the applied current. The manufactured MR clutch is integrated with accelerator pedal on which driver's foot is placed to transmit haptic cue signal. In the meantime, a cue algorithm for gear shifting is formulated by considering vehicle model. The cue algorithm is then integrated with a haptic controller which is a torque model based-compensation strategy regarding Presiach hystersis linearization of the employed MR fluid. In this work, the haptic cue controller is implemented in discrete manner. Control performances are experimentally evaluated such as haptic tracking responses.

  8. Prototype of a mechanical assistance device for the wrists' flexion-extension movement

    International Nuclear Information System (INIS)

    Politti, Julio C; Puglisi, Lisandro J; Farfan, Fernando D

    2007-01-01

    Using CMU actuators, a Prototype of Mechanical Assistance Device for the Wrist's Flexion Movement (PMA) was developed and probed in a mechanical model, in order to be implemented in a future as a dynamic powered orthosis or as a rehabilitation assistant instrument. Two Mayor Actuators conformed by three CMU actuators arranged in a series configuration, allows to an artificial hand to be placed in four predefined positions: 0 0 , 20 0 , 40 0 and 60 0 . The synchronism and control of the actuators is achieved with the Programmable Control Module (PCM). It is capable to drive up to six CMU actuators, and possess two different modes of execution: a Manual mode and an Exercise mode. In the Manual Mode, the position of the hand responds directly to the commands of the keyboard of the front panel, and in the Exercise mode, the hand realizes a repetitive and programmed movement. The prototype was tested in 100 positions in the Manual Mode and for 225 works cycles in the Exercise Mode. The relative repetition error was less than 5% for both test. This prototype only consumes 4,15W, which makes it possible to be powered by small rechargeable batteries, allowing its use as a portable device

  9. Laparoscopy-assisted percutaneous endoscopic gastrostomy using a "Funada-kit II" device.

    Science.gov (United States)

    Takahashi, Toshiaki; Miyano, Go; Shiyanagi, Satoko; Lane, Geoffrey J; Yamataka, Atsuyuki

    2012-09-01

    We aimed at assessing the effect of using a "Funada-kit II" device during laparoscopy-assisted percutaneous endoscopic gastrostomy (Lap-PEG), by reviewing 29 cases of Lap-PEG we performed from 2001 to 2011. We started using the "Funada-kit II" (CREATE MEDIC CO., Kanagawa, Japan) device with two parallel needles to puncture the stomach and assist suturing the anterior gastric wall to the anterior abdominal wall during Lap-PEG in 2011 (F-PEG). By introducing a loop through the lumen of one needle which allows placement of a suture introduced through the lumen of the other needle. Once repeated, the stomach can be pexied at two points, approximately 2 cm apart. We compared Lap-PEG (n = 23) with F-PEG (n = 6) where the mean ages and weights at surgery and sex ratios were similar. All cases were uneventful without intraoperative complications, although one postoperative wound infection occurred in a Lap-PEG case. There were no differences in the duration of analgesia, time taken to commence tube feeding, and return to full feeding. However, mean operating time was significantly shorter in F-PEG (28.1 min) versus Lap-PEG (46.1 min) p < 0.05. As per results F-PEG would appear to be as safe as Lap-PEG, but much quicker.

  10. Utilization of assistive devices for students with disabilities in the public schools

    Directory of Open Access Journals (Sweden)

    Carolina Bastos Plotegher

    2013-04-01

    Full Text Available Introduction: Assistive technology is an area of expanding knowledge in Brazil. Its use in school can help students with disabilities in performing important tasks to participate in different activities. Objectives: to report the experience of using assistive devices in the academic achievement of students with disabilities included in the regular school system of the municipality of Sao Carlos, state of Sao Paulo. Method: it was developed from an extension project conducted in 2010. Thirteen students with various types of disabilities participated in the project. The interventions were based on the School Function Assessment with the teachers to know the students’ difficulties. The students were also observed performing school tasks. Results: Forty-seven adaptations were made: thickeners, rings for zippers, slants, communication boards, non-slip mats, among others. Besides the adjustments, orientation regarding use of the devices was provided for teachers and persons responsible for the students. Conclusion: we believe that the project benefited the students, because it produced higher academic achievement and provided better school conditions for their school inclusion. For the undergraduate students of Occupational Therapy, the project enabled the dealing with real issues of inclusion and school interventions, thus approaching theory to practice.

  11. Prototype of a mechanical assistance device for the wrists' flexion-extension movement

    Energy Technology Data Exchange (ETDEWEB)

    Politti, Julio C; Puglisi, Lisandro J; Farfan, Fernando D [Departamento de BioingenierIa - FaCEyT - UNT (Argentina)

    2007-11-15

    Using CMU actuators, a Prototype of Mechanical Assistance Device for the Wrist's Flexion Movement (PMA) was developed and probed in a mechanical model, in order to be implemented in a future as a dynamic powered orthosis or as a rehabilitation assistant instrument. Two Mayor Actuators conformed by three CMU actuators arranged in a series configuration, allows to an artificial hand to be placed in four predefined positions: 0{sup 0}, 20{sup 0}, 40{sup 0} and 60{sup 0}. The synchronism and control of the actuators is achieved with the Programmable Control Module (PCM). It is capable to drive up to six CMU actuators, and possess two different modes of execution: a Manual mode and an Exercise mode. In the Manual Mode, the position of the hand responds directly to the commands of the keyboard of the front panel, and in the Exercise mode, the hand realizes a repetitive and programmed movement. The prototype was tested in 100 positions in the Manual Mode and for 225 works cycles in the Exercise Mode. The relative repetition error was less than 5% for both test. This prototype only consumes 4,15W, which makes it possible to be powered by small rechargeable batteries, allowing its use as a portable device.

  12. Communicating with assistive listening devices and age-related hearing loss: Perceptions of older Australians.

    Science.gov (United States)

    Aberdeen, Lucinda; Fereiro, David

    2014-01-01

    Abstract Age-related hearing loss can impact adversely on the delivery of primary care and cannot necessarily be remedied by hearing aid technology. A study of 20 older Australians living in a Queensland retirement village and residential hostel complex was undertaken to investigate how communication might be advanced through an assistive listening device (ALD). Most participants were women aged over 85 years; almost all had hearing loss and wore hearing aids. Tests with an ALD found very high levels of satisfaction with understanding speech and sound quality amongst participants. However, few had heard previously of ALDs, all required individualised assistance to fit and use the device and rated ease of use less highly. The findings affirm those of previous studies that ALD technology has a role in communication for older hearing impaired people and for hearing rehabilitation. Its potential to enhance quality of life can be facilitated and promoted through nursing practice, but requires professional and consumer education so that it is not overlooked as a communication option.

  13. Environmental barriers to participation and facilitators for use of three types of assistive technology devices.

    Science.gov (United States)

    Widehammar, Cathrine; Lidström, Helene; Hermansson, Liselotte

    2017-08-07

    The aim was to compare the presence of environmental barriers to participation and facilitators for assistive technology (AT) use and study the relation between barriers and AT use in three different AT devices. A cross-sectional survey was conducted. Inclusion criteria were ≥one year of experience as a user of myoelectric prosthesis (MEP), powered mobility device (PMD), or assistive technology for cognition (ATC) and age 20-90 years. Overall, 156 participants answered the Swedish version of the Craig Hospital Inventory of Environmental Factors and a study-specific questionnaire on facilitating factors. Non-parametric tests were used for comparisons. Barriers to participation were lowest in MEP users (md=0.12; p>0.001), and highest in ATC users (md=1.56; p>0.001) with the least support for AT use (p>0.001 - p=0.048). A positive correlation between fewer barriers and higher use of MEP was seen (r=0.30, p=0.038). The greatest barriers to participation were Natural environment, Surroundings and Information, and the most support came from relatives and professionals. Support, training and education are vital in the use of AT. These factors may lead to a more sustained and prolonged use of AT and may enable increased participation. Future research should focus on interventions that meet the needs of people with cognitive disabilities.

  14. Intraoperative Transesophageal Echocardiography and Right Ventricular Failure After Left Ventricular Assist Device Implantation.

    Science.gov (United States)

    Silverton, Natalie A; Patel, Ravi; Zimmerman, Josh; Ma, Jianing; Stoddard, Greg; Selzman, Craig; Morrissey, Candice K

    2018-02-15

    To determine whether intraoperative measures of right ventricular (RV) function using transesophageal echocardiography are associated with subsequent RV failure after left ventricular assist device (LVAD) implantation. Retrospective, nonrandomized, observational study. Single tertiary-level, university-affiliated hospital. The study comprised 100 patients with systolic heart failure undergoing elective LVAD implantation. Transesophageal echocardiographic images before and after cardiopulmonary bypass were analyzed to quantify RV function using tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (S'), fractional area change (FAC), RV global longitudinal strain, and RV free wall strain. A chart review was performed to determine which patients subsequently developed RV failure (right ventricular assist device placement or prolonged inotrope requirement ≥14 days). Nineteen patients (19%) subsequently developed RV failure. Postbypass FAC was the only measure of RV function that distinguished between the RV failure and non-RV failure groups (21.2% v 26.5%; p = 0.04). The sensitivity, specificity, and area under the curve of an abnormal RV FAC (failure after LVAD implantation were 84%, 20%, and 0.52, respectively. No other intraoperative measure of RV function was associated with subsequent RV failure. RV failure increased ventilator time, intensive care unit and hospital length of stay, and mortality. Intraoperative measures of RV function such as tricuspid annular plane systolic excursion, tricuspid annular systolic velocity, and RV strain were not associated with RV failure after LVAD implantation. Decreased postbypass FAC was significantly associated with RV failure but showed poor discrimination. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

    Science.gov (United States)

    Marasco, Silvana F; Lo, Casey; Murphy, Deirdre; Summerhayes, Robyn; Quayle, Margaret; Zimmet, Adam; Bailey, Michael

    2016-01-01

    In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  16. Radiofrequency-assisted liposuction device for body contouring: 97 patients under local anesthesia.

    Science.gov (United States)

    Theodorou, Spero J; Paresi, Robert J; Chia, Christopher T

    2012-08-01

    Radiofrequency-assisted liposuction involves the delivery of a controlled amount of energy to treated tissue resulting in fat liquefaction, accompanying hemostasis, and skin tightening. The purpose of this study is to report experience with a larger sample size using the BodyTite™ radiofrequency-assisted liposuction (RFAL) platform, and its first use with local tumescent anesthesia. The Bodytite™ device is currently awaiting FDA approval. We prospectively included 97 patients who underwent radiofrequency-assisted liposuction under local anesthesia under IRB approval. We treated 144 anatomical areas in 132 operations and collected the following data: age, sex, height, weight, body mass index (BMI), anatomical area of treatment, operative time, amount of tumescent solution used, amount of fat aspirated, amount of kilojoules (kJ) delivered, and the incidence of infections, seromas, adverse effects from medications, and thermal injuries. Patients were asked to complete an online survey assessing the aesthetic outcome and quality of life after treatment with RFAL-assisted liposuction. Three independent plastic surgeons were asked to evaluate photographs of our 6-month postoperative results in comparison to the preoperative photos. The average age and BMI of our study population was 37.6 years and 28.2 kg/m2, respectively. The study population was 88% female. The mean amount of lidocaine given per treatment session was 32.7 mg/kg (range=3.8-83.3 mg/kg). The mean amount of tumescent fluid given per anatomical treatment area was 1,575 cc. The average amount of total aspirate across all anatomical treatment areas was 1,050 cc, with an average total aspirate of 1,146 cc per treatment date. The overall incidence of major complications was 6.25% and the incidence of minor complications was 8.3%. Overall patient satisfaction was 82% for the degree of skin tightening and 85% for the body-contouring result with the BodyTite™ device. Three independent plastic surgeons graded

  17. Cross-cultural adaptation of the assistive technology device - Predisposition assessment (ATD PA) for use in Brazil (ATD PA Br).

    Science.gov (United States)

    Alves, Ana Cristina de Jesus; Matsukura, Thelma Simões; Scherer, Marcia J

    2017-02-01

    The purpose of this study is to conduct a cross-cultural adaptation of the Assistive Technology Device Predisposition Assessment (ATD PA) for use in Brazil. The selection of the Assistive Technology Device Predisposition Assessment (ATD PA) was determined by previous literature reviews of articles published in 2014 and 2016 in six databases with the terms "assistive device" or "assistive technology" or "self-help device" combined with "evidence-based practice" or "framework" or "measurement scale" or "model and outcome assessment". This review indicated that the conceptual model of Assistive Technology (AT) most discussed in the literature was the Matching Person and Technology (MPT) model, and this finding determined the selection of ATD PA as an assessment within the MPT portfolio of measures. The procedures for cross-cultural adaptation were as follows: Equivalence of Concept, Semantic and Operational. Five experts were asked to translate 725 items and these translations were evaluated and a high level of agreement was demonstrated. The Portuguese version, Avaliação de Tecnologia Assistiva - Predisposição ao Uso - ATD PA Br, was derived from the original version in English (ATD PA). The ATD PA Br will support professionals and people with disabilities in Brazil to better select AT devices according to the clients' needs. Implications for rehabilitation Provides a systematic way of selecting assistive technology devices for the use of individuals with disabilities according to the Brazilian reality. A systematic way of selecting the assistive technology that can help decrease the abandonment of the assistive technology use. The use of the Matching Person and Technology theorical model and of the assessment ATD PA Br is essential to guide the researches and clinical practice in Brazil.

  18. Left Ventricular Assist Device Malfunctions: It Is More Than Just the Pump.

    Science.gov (United States)

    Kormos, Robert L; McCall, Michael; Althouse, Andrew; Lagazzi, Luigi; Schaub, Richard; Kormos, Michael A; Zaldonis, Jared A; Sciortino, Christopher; Lockard, Kathleen; Kuntz, Nicole; Dunn, Elizabeth; Teuteberg, Jeffrey J

    2017-10-31

    Reports of left ventricular assist device (LVAD) malfunction have focused on pump thrombosis. However, the device consists of the pump, driveline, and peripherals, all of which are potentially subject to failure. Prospectively collected data were reviewed for all LVAD device malfunctions (DMs) occurring in rotary LVADs implanted at a single center between April 2004 and May 2016. Durable LVADs included 108 Heartmate II (HM II) and 105 HeartWare VAD (HVAD). DM data were categorized according to device type and into categories related to the component that failed: (1) controller, (2) peripheral components, and (3) implantable blood pump or its integral electric driveline. Pump-related events were analyzed as pump-specific (suspected or confirmed thrombosis) or nonpump-specific (driveline failure). DM rates were reported as events per 1000 patient-days, and Cox proportional hazard models were used for time-to-event analyses. Cumulative rates of malfunction were examined for the main components of each type of LVAD. Types of DM included controller failure (30%), battery failure (19%), or patient cable failure (14%), whereas only 13% were because of pump failure. DMs were more common in the HM II device (3.73 per 1000 patient-days versus 3.06 per 1000 patient-days for the HVAD, P pump-specific malfunctions was discovered in those implanted with an HM II versus an HVAD (0.55 versus 0.39, respectively; P pump-specific malfunction at 3 years compared with 56% for the HM II (log-rank P pump thrombosis at 3 years compared with 90% of the patients with HVAD. Freedom from failure of the integrated driveline was 79% at 3 years for the HM II but 100% for the HVAD (log-rank P pump failure alone and occurs for different components at different rates based on the type of LVAD. © 2017 American Heart Association, Inc.

  19. Validation of a laser-assisted wound measurement device in a wound healing model.

    Science.gov (United States)

    Constantine, Ryan S; Bills, Jessica D; Lavery, Lawrence A; Davis, Kathryn E

    2016-10-01

    In the treatment and monitoring of a diabetic or chronic wound, accurate and repeatable measurement of the wound provides indispensable data for the patient's medical record. This study aims to measure the accuracy of the laser-assisted wound measurement (LAWM) device against traditional methods in the measurement of area, depth and volume. We measured four 'healing' wounds in a Play-Doh(®) -based model over five subsequent states of wound healing progression in which the model was irregularly filled in to replicate the healing process. We evaluated the LAWM device against traditional methods including digital photograph assessment with National Institutes of Health ImageJ software, measurements of depth with a ruler and weight-to-volume assessment with dental paste. Statistical analyses included analysis of variance (ANOVA) and paired t-tests. We demonstrate that there are significantly different and nearly statistically significant differences between traditional ruler depth measurement and LAWM device measurement, but there are no statistically significant differences in area measurement. Volume measurements were found to be significantly different in two of the wounds. Rate of percentage change was analysed for volume and depth in the wound healing model, and the LAWM device was not significantly different than the traditional measurement technique. While occasionally inaccurate in its absolute measurement, the LAWM device is a useful tool in the clinician's arsenal as it reliably measures rate of percentage change in depth and volume and offers a potentially aseptic alternative to traditional measurement techniques. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  20. Electric poling-assisted additive manufacturing process for PVDF polymer-based piezoelectric device applications

    International Nuclear Information System (INIS)

    Lee, ChaBum; Tarbutton, Joshua A

    2014-01-01

    This paper presents a new additive manufacturing (AM) process to directly and continuously print piezoelectric devices from polyvinylidene fluoride (PVDF) polymeric filament rods under a strong electric field. This process, called ‘electric poling-assisted additive manufacturing or EPAM, combines AM and electric poling processes and is able to fabricate free-form shape piezoelectric devices continuously. In this process, the PVDF polymer dipoles remain well-aligned and uniform over a large area in a single design, production and fabrication step. During EPAM process, molten PVDF polymer is simultaneously mechanically stresses in-situ by the leading nozzle and electrically poled by applying high electric field under high temperature. The EPAM system was constructed to directly print piezoelectric structures from PVDF polymeric filament while applying high electric field between nozzle tip and printing bed in AM machine. Piezoelectric devices were successfully fabricated using the EPAM process. The crystalline phase transitions that occurred from the process were identified by using the Fourier transform infrared spectroscope. The results indicate that devices printed under a strong electric field become piezoelectric during the EPAM process and that stronger electric fields result in greater piezoelectricity as marked by the electrical response and the formation of sharper peaks at the polar β crystalline wavenumber of the PVDF polymer. Performing this process in the absence of an electric field does not result in dipole alignment of PVDF polymer. The EPAM process is expected to lead to the widespread use of AM to fabricate a variety of piezoelectric PVDF polymer-based devices for sensing, actuation and energy harvesting applications with simple, low cost, single processing and fabrication step. (paper)

  1. Assistive control of motion therapy devices based on pneumatic soft-actuators with rotary elastic chambers.

    Science.gov (United States)

    Wilkening, André; Baiden, David; Ivlev, Oleg

    2011-01-01

    Robot assisted motion therapy attains increasingly importance and acceptance especially in neurorehabilitation after stroke or spinal injury, but also in orthopedic rehabilitation and surgical interventions. Several studies have shown that a patient-cooperative (assistive) motion therapy, which activates remaining muscle strength and so optimizes recovery, will cause a much higher effectiveness compared to commonly used continuous passive motion (CPM) machines with pre-programmed trajectories (motion profiles). This article describes an assistive control concept developed for orthopedic rehabilitation based on inherent compliant (soft) actuators. Control concept takes into acccount specific properties of physiotherapists behavior during treatment. The patient will be supported and at the same time encouraged to generate own muscular strength to perform desired movement. Concept has been implemented for two prototypes of motion therapy devices (MTD) for knee and shoulder motion therapy. The first prototype (Knee-MTD) has been extensively tested with healthy persons and now is being tested in the Clinic for Orthopaedics and Trauma Surgery of Klinikum Stuttgart to prove concept in real-life conditions. © 2011 IEEE

  2. A Physiological Controller for Turbodynamic Ventricular Assist Devices Based on Left Ventricular Systolic Pressure.

    Science.gov (United States)

    Petrou, Anastasios; Ochsner, Gregor; Amacher, Raffael; Pergantis, Panagiotis; Rebholz, Mathias; Meboldt, Mirko; Schmid Daners, Marianne

    2016-09-01

    The current article presents a novel physiological feedback controller for turbodynamic ventricular assist devices (tVADs). This controller is based on the recording of the left ventricular (LV) pressure measured at the inlet cannula of a tVAD thus requiring only one pressure sensor. The LV systolic pressure (SP) is proposed as an indicator to determine the varying perfusion requirements. The algorithm to extract the SP from the pump inlet pressure signal used for the controller to adjust the speed of the tVAD shows robust behavior. Its performance was evaluated on a hybrid mock circulation. The experiments with changing perfusion requirements were compared with a physiological circulation and a pathological one assisted with a tVAD operated at constant speed. A sensitivity analysis of the controller parameters was conducted to identify their limits and their influence on a circulation. The performance of the proposed SP controller was evaluated for various values of LV contractility, as well as for a simulated pressure sensor drift. The response of a pathological circulation assisted by a tVAD controlled by the introduced SP controller matched the physiological circulation well, while over- and underpumping events were eliminated. The controller presented a robust performance during experiments with simulated pressure sensor drift. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  3. Mechanical circulatory assist device development at the Texas Heart Institute: a personal perspective.

    Science.gov (United States)

    Frazier, O H

    2014-01-01

    In December 2013, we performed our 1000th ventricular assist device implantation at the Texas Heart Institute. In my professional career, I have been fortunate to see the development of numerous mechanical circulatory support devices for the treatment of patients with advanced heart failure. In fact, most of the cardiac pumps in wide use today were developed in the Texas Heart Institute research laboratories in cooperation with the National Heart, Lung and Blood Institute or device innovators and manufacturers and implanted clinically at our partner St. Luke's Episcopal Hospital. My early involvement in this field was guided by my mentors, Dr Michael E. DeBakey and, especially, Dr Denton A. Cooley. Also, many of the advances are directly attributable to my ongoing clinical experience. What I learned daily in my surgical practice allowed me to bring insights to the development of this technology that a laboratory researcher alone might not have had. Young academic surgeons interested in this field might be well served to be active not only in laboratory research but also in clinical practice. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Mechanisms and clinical applications of the vacuum-assisted closure (VAC) Device: a review.

    Science.gov (United States)

    Venturi, Mark L; Attinger, Christopher E; Mesbahi, Ali N; Hess, Christopher L; Graw, Katherine S

    2005-01-01

    The use of sub-atmospheric pressure dressings, available commercially as the vacuum-assisted closure (VAC) device, has been shown to be an effective way to accelerate healing of various wounds. The optimal sub-atmospheric pressure for wound healing appears to be approximately 125 mm Hg utilizing an alternating pressure cycle of 5 minutes of suction followed by 2 minutes off suction. Animal studies have demonstrated that this technique optimizes blood flow, decreases local tissue edema, and removes excessive fluid from the wound bed. These physiologic changes facilitate the removal of bacteria from the wound. Additionally, the cyclical application of sub-atmospheric pressure alters the cytoskeleton of the cells in the wound bed, triggering a cascade of intracellular signals that increases the rate of cell division and subsequent formation of granulation tissue. The combination of these mechanisms makes the VAC device an extremely versatile tool in the armamentarium of wound healing. This is evident in the VAC device's wide range of clinical applications, including treatment of infected surgical wounds, traumatic wounds, pressure ulcers, wounds with exposed bone and hardware, diabetic foot ulcers, and venous stasis ulcers. VAC has also proven useful in reconstruction of wounds by allowing elective planning of the definitive reconstructive surgery without jeopardizing the wound or outcome. Furthermore, VAC has significantly increased the skin graft success rate when used as a bolster over the freshly skin-grafted wound. VAC is generally well tolerated and, with few contraindications or complications, is fast becoming a mainstay of current wound care.

  5. Carotid Artery Stenting in a Patient With a Continuous-Flow Left Ventricular Assist Device.

    Science.gov (United States)

    Piazza, Michele; Squizzato, Francesco; Grego, Franco; Bottio, Tommaso; Gerosa, Gino; Antonello, Michele

    2016-08-01

    To demonstrate the safety and feasibility of carotid artery stenting (CAS) in a patient with a continuous-flow left ventricular assist device (LVAD). A 54-year-old woman with a LVAD was referred for a 90% stenosis of the right internal carotid artery (ICA). The patient was offered CAS, and oral anticoagulant was not discontinued in the periprocedural period. Because of absent arterial pulses, percutaneous transfemoral access was obtained under ultrasound guidance. Particular attention was paid to cannulation of the innominate artery; a 7-F guiding catheter was advanced from the descending aorta into the innominate artery under road-mapping, avoiding maneuvers in the ascending aorta where the outflow Dacron graft of the LVAD was anastomosed. To avoid cerebral flow modifications, the Angioguard RX was used as the cerebral protection device rather than other devices such as the flow reversal or flow-clamping systems. At this point, CAS was performed in a standard fashion using the 7×30-mm Precise ProRX stent. The computed tomography angiogram at 6 months showed patency of the stented right ICA. With adequate planning, CAS appears feasible in patients with a LVAD. © The Author(s) 2016.

  6. Use of Ventricular Assist Device in Univentricular Physiology: The Role of Lumped Parameter Models.

    Science.gov (United States)

    Di Molfetta, Arianna; Ferrari, Gianfranco; Filippelli, Sergio; Fresiello, Libera; Iacobelli, Roberta; Gagliardi, Maria G; Amodeo, Antonio

    2016-05-01

    Failing single-ventricle (SV) patients might benefit from ventricular assist devices (VADs) as a bridge to heart transplantation. Considering the complex physiopathology of SV patients and the lack of established experience, the aim of this work was to realize and test a lumped parameter model of the cardiovascular system, able to simulate SV hemodynamics and VAD implantation effects. Data of 30 SV patients (10 Norwood, 10 Glenn, and 10 Fontan) were retrospectively collected and used to simulate patients' baseline. Then, the effects of VAD implantation were simulated. Additionally, both the effects of ventricular assistance and cavopulmonary assistance were simulated in different pathologic conditions on Fontan patients, including systolic dysfunction, diastolic dysfunction, and pulmonary vascular resistance increment. The model can reproduce patients' baseline well. Simulation results suggest that the implantation of VAD: (i) increases the cardiac output (CO) in all the three palliation conditions (Norwood 77.2%, Glenn 38.6%, and Fontan 17.2%); (ii) decreases the SV external work (SVEW) (Norwood 55%, Glenn 35.6%, and Fontan 41%); (iii) increases the mean pulmonary arterial pressure (Pap) (Norwood 39.7%, Glenn 12.1%, and Fontan 3%). In Fontan circulation, with systolic dysfunction, the left VAD (LVAD) increases CO (35%), while the right VAD (RVAD) determines a decrement of inferior vena cava pressure (Pvci) (39%) with 34% increment of CO. With diastolic dysfunction, the LVAD increases CO (42%) and the RVAD decreases the Pvci. With pulmonary vascular resistance increment, the RVAD allows the highest CO (50%) increment with the highest decrement of Pvci (53%). The single ventricular external work (SVEW) increases (decreases) increasing the VAD speed in cavopulmonary (ventricular) assistance. Numeric models could be helpful in this challenging and innovative field to support patients and VAD selection to optimize the clinical outcome and personalize the therapy

  7. Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, Q; Snyder, J; Wang, C; Guceri, S; Sun, W [Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA (United States); Timmer, M; Hammer, J, E-mail: sunwei@drexel.edu [Advanced Technologies and Regenerative Medicine, Somerville, NJ (United States)

    2011-09-15

    In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 deg. C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 deg. C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

  8. Anesthesia for gastrointestinal endoscopy in patients with left ventricular assist devices: Initial experience with 68 procedures

    Directory of Open Access Journals (Sweden)

    Basavana G Goudra

    2013-01-01

    Full Text Available Aims and Objectives: Continuous flow left ventricular assist devices (LVAD have emerged as a reliable treatment option for heart failure. Because of bleeding secondary to anticoagulation, these patients present frequently for gastrointestinal (GI endoscopy. The presently available literature on perioperative management of these patients is extremely limited and is primarily based upon theoretical principles. Materials and Methods: Perioperative records of patients with LVAD undergoing (GI endoscopy between 2008 and 2012 were reviewed. Patient, device and procedure specific information was analyzed. Results: A total of 105 LVADs were implanted, and 68 procedures were performed in 39 patients. The most common indication was GI bleed (48/68, with yearly risk of 8.57% per patient. A total of 63 procedures were performed under deep sedation, with five procedures requiring general anesthesia. Intra-procedure hypotension was managed by fluids and (or vasopressors/inotropes (phenylephrine, ephedrine or milrinone guided by plethysmographic waveform, non-invasive blood pressure (NIBP and LVADs pulsatility index (for HeartMate II/flow pulsatility (for HeartWare. No patient required invasive monitoring and both NIBP and pulse oximeter could be reliably used for monitoring (and guided management in all patients due to the presence of native heart′s pulsatile output. Conclusion: In the presence of residual heart function, with optimal device settings, non-invasive hemodynamic monitoring can be reliably used in these patients while undergoing GI endoscopy under general anesthesia or monitored anesthesia care. Transient hypotensive episodes respond well to fluids/vasopressors without the need of increasing device speed that can be detrimental.

  9. Development of ventricular assist devices in China: present status, opportunities and challenges.

    Science.gov (United States)

    Gu, Kaiyun; Chang, Yu; Gao, Bin; Wan, Feng; Loisance, Daniel; Zeng, Yi

    2014-08-01

    The growing number of heart failure patients and the scarcity of organ donors account for the huge need for the development of mechanical circulatory systems, including ventricular assist devices (VADs) and artificial hearts, in China. Several research programmes on blood pumps have been under way for the last three decades. However, unlike in other countries, the development of VADs has been extremely slow, and no system is currently approved and available for clinical application. There are many reasons for this situation. This article provides an overview of the present development of experimental and clinical research on VADs in China. In addition, the challenges for the clinical development of mechanical circulatory support in China are discussed. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  10. Singularity now: using the ventricular assist device as a model for future human-robotic physiology.

    Science.gov (United States)

    Martin, Archer K

    2016-04-01

    In our 21 st century world, human-robotic interactions are far more complicated than Asimov predicted in 1942. The future of human-robotic interactions includes human-robotic machine hybrids with an integrated physiology, working together to achieve an enhanced level of baseline human physiological performance. This achievement can be described as a biological Singularity. I argue that this time of Singularity cannot be met by current biological technologies, and that human-robotic physiology must be integrated for the Singularity to occur. In order to conquer the challenges we face regarding human-robotic physiology, we first need to identify a working model in today's world. Once identified, this model can form the basis for the study, creation, expansion, and optimization of human-robotic hybrid physiology. In this paper, I present and defend the line of argument that currently this kind of model (proposed to be named "IshBot") can best be studied in ventricular assist devices - VAD.

  11. Partial Nephrectomy in a Patient with a Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Jules P. Manger

    2011-01-01

    Full Text Available Left ventricular assist device (LVAD use has increased as a bridge to heart transplant as well as destination therapy in patients with severe heart failure. Presence of LVAD is not a contraindication to noncardiac surgery but does present special challenges to the surgical, anesthesia, and cardiac teams. We present the case of a 40-year-old woman with idiopathic cardiomyopathy necessitating LVAD who underwent left partial nephrectomy for a renal mass. She had undergone three nondiagnostic percutaneous image-guided biopsies. Left partial nephrectomy was performed. Perioperative care was without incident due to careful oversight by a multidisciplinary team. Pathology revealed high-grade clear cell renal cell carcinoma (RCC with negative margins. Polytetrafluoroethylene (PTFE bolsters were misidentified six months postoperatively on computed tomography (CT at an outside institution as a retained laparotomy sponge. This is, to our knowledge, the first report of a partial nephrectomy performed in a patient with LVAD.

  12. Asymmetric adaptation in human walking using the Tethered Pelvic Assist Device (TPAD).

    Science.gov (United States)

    Vashista, Vineet; Reisman, Darcy S; Agrawal, Sunil K

    2013-06-01

    Human nervous system is capable of modifying motor commands in response to alterations in walking conditions. Previous research has shown that external perturbations that induce gait asymmetry can lead to adaptation in gait parameters. Such strategies have also been shown to temporarily restore gait symmetry in subjects with post stroke hemiparesis. This work aims to develop an experimental paradigm to induce gait asymmetry in human subjects by applying external asymmetric forces on the pelvis through the Tethered Pelvic Assist Device (TPAD). These external forces on the pelvis have the potential to influence the swing and the stance phases of both legs. Eight healthy subjects participated in the experiment where a higher resistive force was applied on the pelvis during the swing phase of the left leg as compared to the right leg. We hypothesized that such asymmetrically applied forces on the pelvis will lead to asymmetric adaptation in the human walking.

  13. The Impact of Ventricular Assist Device Prior to Transplantation on Morphological Parameters in Cardiac Allografts

    DEFF Research Database (Denmark)

    Wassilew, Katharina

    2017-01-01

    Due to the shortage of donor organs, mechanical circulatory support systems (MCS) are now widely used as a treatment option to bridge the failing heart to transplantation. There are limited data, suggesting that prolonged use of ventricular assist device (VAD) therapy may result in cardiac...... of the level of macrophages on the degree of IF in right ventricular endomyocardial biopsies (EMBs) of cardiac allografts. Methods: We evaluated all consecutive EMBs of cardiac allografts from 254 patients taken between 01/2011 and 12/2012.With regard to pre-transplant MCS treatment, patients were divided....... The Cochran-Mantel-Haenzsel test was applied to assess significance of the differences in interactions between groups. To evaluate the impact of bridge- to- transplant mechanical circulatory support on development on transplant vasculopathy in cardiac allografts, the intramyocardial terminal arterial network...

  14. Dynamic stability analysis of spring loaded safety valves elements for improved valve performance through assistance device

    International Nuclear Information System (INIS)

    Catalani, L.

    1984-08-01

    For a given valve design (internal profile and ring setting), the dynamic performance which depends strongly on the piping t/h response can be judged only in terms of a coupled problem between valve and piping hydraulic transient. To fulfill this aim an analytical model was developed (valve dynamic model coupled with an existing thermal-hydraulics code for the upstream piping) that provides the means to assess the influence of the main parameters on the valve stability: ring setting, upstream fluid conditions (vapour or liquid discharge), upstream piping length (between pressurizer and safety valves). At last, the performance of a spring loaded safety valve may be greatly improved by the introduction of a pneumatic or electromagnetic assistance device

  15. Pump speed modulations and sub-maximal exercise tolerance in left ventricular assist device recipients

    DEFF Research Database (Denmark)

    Jung, Mette Holme; Houston, Brian; Russell, Stuart D

    2017-01-01

    of the 2 sub-maximal tests was determined by randomization. Both patient and physician were blinded to the sequence. Exercise duration, oxygen consumption (VO2) and rate of perceived exertion (RPE), using the Borg scale (score 6 to 20), were recorded. RESULTS: Nineteen patients (all with a HeartMate II...... ventricular assist device) completed 57 exercise tests. Baseline pump speed was 9,326 ± 378 rpm. At AT, workload was 63 ± 26 W (25 to 115 W) and VO2 was 79 ± 14% of maximum. Exercise duration improved by 106 ± 217 seconds (~13%) in Speedinc compared with Speedbase (837 ± 358 vs 942 ± 359 seconds; p = 0...

  16. Exercise physiology, testing, and training in patients supported by a left ventricular assist device.

    Science.gov (United States)

    Loyaga-Rendon, Renzo Y; Plaisance, Eric P; Arena, Ross; Shah, Keyur

    2015-08-01

    The left ventricular assist device (LVAD) is an accepted treatment alternative for the management of end-stage heart failure. As we move toward implantation of LVADs in less severe cases of HF, scrutiny of functional capacity and quality of life becomes more important. Patients demonstrate improvements in exercise capacity after LVAD implantation, but the effect is less than predicted. Exercise training produces multiple beneficial effects in heart failure patients, which would be expected to improve quality of life. In this review, we describe factors that are thought to participate in the persistent exercise impairment in LVAD-supported patients, summarize current knowledge about the effect of exercise training in LVAD-supported patients, and suggest areas for future research. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  17. Left ventricular non-compaction cardiomyopathy and left ventricular assist device: a word of caution.

    Science.gov (United States)

    Kornberger, A; Stock, U A; Risteski, P; Beiras Fernandez, A

    2016-07-15

    In patients with left ventricular non-compaction (LVNC), implantation of a left ventricular assist device (LVAD) may be performed as a bridge to transplantation. In this respect, the particular characteristics of the left ventricular myocardium may represent a challenge. We report a patient with LVNC who required urgent heart transplantation for inflow cannula obstruction nine months after receiving a LVAD. LVAD parameters, echocardiography and examination of the explanted heart suggested changes of left ventricular configuration brought about by LVAD support as the most likely cause of inflow cannula obstruction. We conclude that changes experienced by non-compacted myocardium during LVAD support may give rise to inflow cannula obstruction and flow reduction. Presence of LVNC mandates tight surveillance for changes in LV configuration and LVAD flow characteristics and may justify urgent transplantation listing status.

  18. Computation of residence time in the simulation of pulsatile ventricular assist devices

    Science.gov (United States)

    Long, C. C.; Esmaily-Moghadam, M.; Marsden, A. L.; Bazilevs, Y.

    2014-10-01

    A continuum-based model of particle residence time for moving-domain fluid mechanics and fluid-structure interaction (FSI) computations is proposed, analyzed, and applied to the simulation of an adult pulsatile ventricular assist device (PVAD). Residence time is a quantity of clinical interest for blood pumps because it correlates with thrombotic risk. The proposed technique may be easily implemented in any flow or FSI solver. In the context of PVADs the results of the model may be used to assess how efficiently the pump moves the blood through its interior. Three scalar measures of particle residence time are also proposed. These scalar quantities may be used in the PVAD design with the goal of reducing thrombotic risk.

  19. An Engineering Analysis of the Aortic Valve Dynamics in Patients with Rotary Left Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    George Faragallah

    2013-01-01

    Full Text Available The use of a rotary Left Ventricular Assist Device (LVAD as a bridge-to-recovery treatment is gaining considerable attention in the LVAD research community. Using a mathematical model of the cardiovascular-LVAD system, this paper intends to define the critical control parameters in terms of power and rotational speed of the LVAD to ensure normal dynamics of the aortic valve for different levels of patient's activity and severity of heart failure. The effects of permanent closure of the aortic valve on the hemodynamics of the patient and the pump flow characteristics, if the critical control values are exceeded, are also examined. Additionally, LVAD power and speed control parameters that yield a given percentage of the cardiac cycle during which the aortic valve remains open are examined indicating that the severity of the heart failure is a very important factor in deciding the appropriateness of the LVAD as a bridge-to recovery treatment.

  20. Continuous flow left ventricular assist devices: shared care goals of monitoring and treating patients.

    Science.gov (United States)

    Estep, Jerry D; Trachtenberg, Barry H; Loza, Laurie P; Bruckner, Brian A

    2015-01-01

    Continuous-flow left ventricular assist devices (CF-LVADs) have been clinically adopted as a long-term standard of care therapy option for patients with end-stage heart failure. For many patients, shared care between the care providers at the implanting center and care providers in the community in which the patient resides is a clinical necessity. The aims of this review are to (1) provide a rationale for the outpatient follow-up exam and surveillance testing used at our center to monitor patients supported by the HeartMate II(®) CF-LVAD (Thoratec Corporation, Pleasanton, CA) and (2) provide the protocol/algorithms we use for blood pressure, driveline exit site, LVAD alarm history, surveillance blood work, and echocardiography monitoring in this patient population. In addition, we define our partnership outpatient follow-up protocol and the "shared care" specific responsibilities we use with referring health care providers to best manage many of our patients.

  1. Right Ventricular Versus Biventricular Pacing for Heart Failure and Atrioventricular Block.

    Science.gov (United States)

    Beck, Hiroko; Curtis, Anne B

    2016-10-01

    The use of cardiac resynchronization therapy (CRT) is well accepted as an important option for the treatment of patients with systolic heart failure and prolonged QRS duration. CRT for patients with narrow QRS complexes is reserved for patients who are undergoing implantation of new or replacement pacemakers or implantable cardioverter defibrillators with an anticipated significant requirement for ventricular pacing. The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial examined the role of CRT in heart failure patients with atrioventricular block and demonstrated significantly better outcomes with CRT compared to right ventricular pacing. On the other hand, conflicting preliminary data were reported by the Biventricular Pacing for Atrioventricular Block to Prevent Cardiac Desynchronization (BioPace) Trial investigators. In this review, we will discuss the adverse consequences of chronic right ventricular pacing, the options of alternate pacing sites in the right ventricle versus biventricular pacing, and the findings from the BLOCK HF Trial as well as the preliminary data from the BioPace Trial. Our goal is to explore the role of biventricular pacing in patients with atrioventricular block.

  2. Stability effects of singularities in force-controlled robotic assist devices

    Science.gov (United States)

    Luecke, Greg R.

    2002-02-01

    Force feedback is being used as an interface between humans and material handling equipment to provide an intuitive method to control large and bulky payloads. Powered actuation in the lift assist device compensates for the inertial characteristics of the manipulator and the payload to provide effortless control and handling of manufacturing parts, components, and assemblies. The use of these Intelligent Assist Devices (IAD) is being explored to prevent worker injury, enhance material handling performance, and increase productivity in the workplace. The IAD also provides the capability to shape and control motion in the workspace during routine operations. Virtual barriers can be developed to protect fixed objects in the workspace, and regions can be programmed that attract the work piece to a certain position and orientation. However, the robot is still under complete control of the human operator, with the trajectory being determined and commanded using the judgment of the operator to complete a given task. In many cases, the IAD is built in a configuration that may have singular points inside the workspace. These singularities can cause problems when the unstructured trajectory commands from the human cause interaction between the IAD and the virtual walls and fixtures at positions close to these singularities. The research presented here explores the stability effects of the interactions between the powered manipulator and the virtual surfaces when controlled by the operator. Because of the flexible nature of the human decisions determining the real time work piece paths, manipulator singularities that occur in conjunction with the virtual surfaces raise stability issues in the performance around these singularities. We examine these stability issues in the context of a particular IAD configuration, and present analytic results for the performance and stability of these systems in response to the real-time trajectory modification of the human operator.

  3. Handcrafted Vacuum-Assisted Device for Skin Ulcers Treatment Versus Traditional Therapy, Randomized Controlled Trial.

    Science.gov (United States)

    Gonzalez, Israel Gonzalez; Angel, Medina Andrade Luis; Baez, Maria Valeria Jimenez; Ruiz Flores, Brenda; de Los Angeles Martinez Ferretiz, Maria; Woolf, Stephanny Vanestty; López, Israel; Sandoval-Jurado, Luis; Pat-Espadas, Fany Guadalupe; Cruz, Alan Alejandro Reyes; Delgado, Arsenio Torres

    2017-02-01

    Chronic lower limb ulcers constitute a public health problem, with important socioeconomic implications and high attention cost. This trial evaluates handcrafted vacuum-assisted therapy versus traditional treatment effectiveness for lower limbs ulcers. It was a prospective randomized clinical trial conducted over 144 patients with lower limbs ulcers. Patients were randomized into two groups of 72 patients: Experimental group were treated with debridement, cure and a handcrafted vacuum-assisted device that was changed every 72 h. Control group was treated with debridement and cure with soap every 24 h. Ulcers were evaluated every 72 h and on 10th day. The presence of systemic inflammatory response, pain, granulation tissue and viability for discharge was registered and analyzed . After exclusion of 18 patients, 126 were included, 65.1% were men with an average of 58 years. Sole region ulcer by diabetic foot was the more frequent in both groups (73%). Leukocytes count, systemic inflammatory response and pain were significantly lower in experimental group (p ulcers. This system would benefit patients favoring earlier infection control, faster granulation tissue appearance and earlier discharge. Clinical trials registered in https://www.clinicaltrials.gov/ Number NCT02512159.

  4. Changing pulsatility by delaying the rotational speed phasing of a rotary left ventricular assist device.

    Science.gov (United States)

    Date, Kazuma; Nishimura, Takashi; Arakawa, Mamoru; Takewa, Yoshiaki; Kishimoto, Satoru; Umeki, Akihide; Ando, Masahiko; Mizuno, Toshihide; Tsukiya, Tomonori; Ono, Minoru; Tatsumi, Eisuke

    2017-03-01

    Continuous-flow left ventricular assist devices (LVADs) have improved the prognosis of end-stage heart failure. However, continuous-flow LVADs diminish pulsatility, which possibly result in bleeding, aortic insufficiency, and other adverse effects. We previously developed a novel control system for a continuous-flow LVAD (EVAHEART ® ; Sun Medical), and demonstrated that we could create sufficient pulsatility by increasing its rotational speed (RS) in the systolic phase (Pulsatile Mode) in the normal heart model. Here, we aimed to evaluate differences between systolic assist with advanced and delayed loads by shifting the timing of increased RS. We implanted EVAHEART in six goats (55.3 ± 4.3 kg) with normal hearts. We reduced their heart rates to ventricular pacing. We shifted the timing of increasing RS from -60 to +60 ms in the systolic phase. We found significant increases in all the following parameters when assessments of delayed timing (+60 ms) were compared with assessments of advanced timing (-60 ms): pulse pressure, mean dP/dt max of aortic pressure, and energy-equivalent pulse pressure. During continuous-flow LVAD support, pulsatility can be controlled using a rotary pump. In particular, pulsatility can be shifted by delaying increased RS.

  5. Stroke rehabilitation: assistive technology devices and environmental modifications following primary rehabilitation in hospital--a therapeutic perspective

    DEFF Research Database (Denmark)

    Sørensen, Hanne Vinkel; Lendal, Susie; Schultz-Larsen, Kirsten

    2003-01-01

    The aim of this article is to describe the need for assistive devices and environmental modifications among long-living stroke survivors and to investigate if the need is continued and growing over time. The study sample of 155 consecutive stroke patients with stroke-related impairment, discharged...... the proportion was 81%. The aids most frequently prescribed were bath seats, aids for mobility, grab bars, and removal of door thresholds. At follow-up 3-5 years later, 74% of the survivors were seen (76 patients). Almost all of the survivors were dependent on assistive devices and/or environmental modifications...

  6. Satisfaction with assistive technology device in relation to the service delivery process-A systematic review.

    Science.gov (United States)

    Larsson Ranada, Åsa; Lidström, Helene

    2017-09-11

    The service delivery process (SDP) of assistive technology devices (ATDs) is attracting interest, as the provision of ATDs is critical for the independence and participation in society of individuals with disabilities. The purpose of the current study was to investigate what impact the SDP has on satisfaction with ATDs in individuals with disabilities in relation to everyday activities. A systematic literature review was conducted, which resulted in 53 articles included. The results showed that there are factors in almost all the different steps of the SDP that affect the satisfaction with of the devices, which can lead to underutilization and abandonment of ATDs. Only a few studies have been conducted with a design robust enough to generalize the results; therefore, more research is needed. Therefore, the conclusion is the SDP as a whole contributes to the satisfaction with and usability of ATDs in individuals with disability in relation to achieving the desired goals of participation in everyday activities, for the articles included must be deemed as moderate. A client-centred approach in the process is advocated, and was found to be an important factor for an effective SDP and satisfied users.

  7. HeartMate II Left Ventricular Assist Device Pump Exchange: A Single-Institution Experience.

    Science.gov (United States)

    Shaikh, Asad F; Joseph, Susan M; Lima, Brian; Hall, Shelley A; Malyala, Rajasekhar; Rafael, Aldo E; Gonzalez-Stawinski, Gonzalo V; Chamogeorgakis, Themistokles

    2017-08-01

    Background  Left ventricular assist devices (LVADs) have revolutionized the treatment of patients with end-stage heart failure. These devices are replaced when pump complications arise if heart transplant is not possible. We present our experience with HeartMate II (HMII (Thoratec, Plesanton, California, United States)) LVAD pump exchange. Materials and Methods  We retrospectively reviewed all cases that required pump exchange due to LVAD complication from November 2011 until June 2016 at a single high-volume institution. The indications, demographics, and outcome were extracted and analyzed. Results  Of 250 total patients with implanted HMII LVADs, 16 (6%) required pump exchange during the study period. The initial indications for LVAD placement in these patients were bridge to transplantation ( n  = 6 [37.5%]) or destination therapy ( n  = 10 [62.5%]). Fifteen patients (93.8%) required pump exchange due to pump thrombosis and 1 (6.2%) due to refractory driveline infection. Nine patients (56.2%) underwent repeat median sternotomy while a left subcostal approach was used in the remaining seven patients. Fifteen patients (93.7%) survived until hospital discharge. During the follow-up period (median, 155 days), 11 patients remained alive and 4 of these underwent successful cardiac transplantation. Conclusion  HMII LVAD pump exchange can be safely performed for driveline infection or pump thrombosis when heart transplantation is not an option. Georg Thieme Verlag KG Stuttgart · New York.

  8. Design of inductive sensors for tongue control system for computers and assistive devices.

    Science.gov (United States)

    Lontis, Eugen R; Struijk, Lotte N S A

    2010-07-01

    The paper introduces a novel design of air-core inductive sensors in printed circuit board (PCB) technology for a tongue control system. The tongue control system provides a quadriplegic person with a keyboard and a joystick type of mouse for interaction with a computer or for control of an assistive device. Activation of inductive sensors was performed with a cylindrical, soft ferromagnetic material (activation unit). Comparative analysis of inductive sensors in PCB technology with existing hand-made inductive sensors was performed with respect to inductance, resistance, and sensitivity to activation when the activation unit was placed in the center of the sensor. Optimisation of the activation unit was performed in a finite element model. PCBs with air-core inductive sensors were manufactured in a 10 layers, 100 microm and 120 microm line width technology. These sensors provided quality signals that could drive the electronics of the hand-made sensors. Furthermore, changing the geometry of the sensors allowed generation of variable signals correlated with the 2D movement of the activation unit at the sensors' surface. PCB technology for inductive sensors allows flexibility in design, automation of production and ease of possible integration with supplying electronics. The basic switch function of the inductive sensor can be extended to two-dimensional movement detection for pointing devices.

  9. A study on ship automatic berthing with assistance of auxiliary devices

    Directory of Open Access Journals (Sweden)

    Van Luong Tran

    2012-09-01

    Full Text Available The recent researches on the automatic berthing control problems have used various kinds of tools as a control method such as expert system, fuzzy logic controllers and artificial neural network (ANN. Among them, ANN has proved to be one of the most effective and attractive options. In a marine context, the berthing maneuver is a complicated procedure in which both human experience and intensive control operations are involved. Nowadays, in most cases of berthing operation, auxiliary devices are used to make the schedule safer and faster but none of above researches has taken into account. In this study, ANN is applied to design the controllers for automatic ship berthing using assistant devices such as bow thruster and tug. Using back-propagation algorithm, we trained ANN with set of teaching data to get a minimal error between output values and desired values of four control outputs including rudder, propeller revolution, bow thruster and tug. Then, computer simulations of automatic berthing were carried out to verify the effecttiveness of the system. The results of the simulations showed good performance for the proposed berthing control system.

  10. Non-Invasive Mapping of Intraventricular Flow Patterns in Patients Treated with Left Ventricular Assist Devices

    Science.gov (United States)

    Miramontes, Marissa; Rossini, Lorenzo; Braun, Oscar; Brambatti, Michela; Almeida, Shone; Mizeracki, Adam; Martinez-Legazpi, Pablo; Benito, Yolanda; Bermejo, Javier; Kahn, Andrew; Adler, Eric; Del Álamo, Juan C.

    2017-11-01

    In heart failure patients, left ventricular (LV) assist devices (LVADs) decrease mortality and improve quality of life. We hypothesize echo color Doppler velocimetry (echo-CDV), an echocardiographic flow mapping modality, can non-invasively characterize the effect of LVAD support, optimize the device, thereby decreasing the stoke rate present in these patients. We used echo-CDV to image LV flow at baseline LVAD speed and during a ramp test in LVAD patients (Heartmate II, N =10). We tracked diastolic vortices and mapped blood stasis and cumulative shear. Compared to dilated cardiomyopathy (DCM) patients without LVADs, the flow had a less prominent diastolic vortex ring, and transited directly from mitral valve to cannula. Residence time and shear were significantly lower compared to healthy controls and DCMs. Aortic regurgitation and a large LV vortex presence or a direct mitral jet towards the cannula affected blood stasis region location and size. Flow patterns, residence time and shear depended on LV geometry, valve function and LVAD speed in a patient specific manner. This new methodology could be used with standard echo, hemodynamics and clinical information to find the flow optimizing LAVD setting minimizing stasis for each patient.

  11. Practical approaches to commencing device-assisted therapies for Parkinson disease in Australia.

    Science.gov (United States)

    Williams, David R; Evans, Andrew H; Fung, Victor S C; Hayes, Michael; Iansek, Robert; Kimber, Thomas; O'Sullivan, John D; Sue, Carolyn M

    2017-10-01

    In Australia 1% of individuals aged over 50 years have Parkinson disease (PD). Guidance for commencing device-assisted therapies (DAT) for PD in Australia was developed based on a review of European recommendations and their relevance to the local clinical setting. An online survey and teleconference discussions were held by a group of eight local movement disorder experts to develop consensus. Referral to a movement disorder specialist and consideration of DAT is appropriate when motor fluctuations cause disability or reduced quality of life, response to treatment is inconsistent or motor fluctuations and dyskinesias require frequent treatment adjustment without apparent benefit and levodopa is required four or more times daily. Three types of DAT are available in Australia for patients with PD: continuous subcutaneous apomorphine; continuous levodopa-carbidopa intestinal gel infusion; and deep brain stimulation. All improve consistency of motor response. The most important aspects when considering which DAT to use are the preferences of the patient and their carers, patient comorbidities, age, cognitive function and neuropsychiatric status. Patients and their families need to be provided with treatment options that are suitable to them, with adequate explanations regarding the recommendations and comparison of potential device-related complications. DAT are best managed, where possible, in a specialist centre with experience in all three types of therapy. Proactive and early management of symptoms during disease progression is essential to maintain optimally motor responses and quality of life in patients with PD. © 2017 Royal Australasian College of Physicians.

  12. [Temporary use of centrifugal pump for pump thrombosis in patients with paracorporeal ventricular assist device].

    Science.gov (United States)

    Kimura, Mitsutoshi; Kinoshita, Osamu; Nawata, Kan; Yamauchi, Haruo; Itoda, Yoshifumi; Hoshino, Yasuhiro; Kashiwa, Koichi; Kubo, Hitoshi; Kurosawa, Hideo; Takahashi, Mai; Koga, Sayaka; Ono, Minoru

    2015-05-01

    Nipro paracorporeal ventricular assist device( VAD) is often associated with pump thrombosis which causes severe complications such as brain infarction, often requiring pump change. However, Nipro VAD pump is an expensive device and it is difficult to change pumps frequently at a short interval. We have temporarily used Rotaflow centrifugal pump for recurrent pump thrombosis in patients with Nipro VADs. From January 2012 through December 2013, 19 patients underwent Nipro VADs implantation at our institution, and 9 of them underwent pump change from Nipro pumps to Rotaflow centrifugal pumps. A total of 25 Rotaflow centrifugal pumps were used in these 9 patients, with the total circulatory support duration of 526 days. The median support period was 15 days (range;2-128 days). There were 2 cerebrovascular accidents and 1 Rotaflow pump circuit thrombosis during this period. Change from Rotaflow to Nipro VAD pump resulted in decrease in hematocrit by about 3 point. There was no difference in liver or renal function between before and after the pump change. Our results suggest that temporary use of Rotaflow centrifugal pump for recurrent pump thrombosis in patients with Nipro VADs may be a promising alternative.

  13. Centrifugal blood pump for temporary ventricular assist devices with low priming and ceramic bearings.

    Science.gov (United States)

    Leme, Juliana; da Silva, Cibele; Fonseca, Jeison; da Silva, Bruno Utiyama; Uebelhart, Beatriz; Biscegli, José F; Andrade, Aron

    2013-11-01

    A new model of centrifugal blood pump for temporary ventricular assist devices has been developed and evaluated. The design of the device is based on centrifugal pumping principles and the usage of ceramic bearings, resulting in a pump with reduced priming (35 ± 2 mL) that can be applied for up to 30 days. Computational fluid dynamic (CFD) analysis is an efficient tool to optimize flow path geometry, maximize hydraulic performance, and minimize shear stress, consequently decreasing hemolysis. Initial studies were conducted by analyzing flow behavior with different impellers, aiming to determine the best impeller design. After CFD studies, rapid prototyping technology was used for production of pump prototypes with three different impellers. In vitro experiments were performed with those prototypes, using a mock loop system composed of Tygon tubes, oxygenator, digital flow meter, pressure monitor, electronic driver, and adjustable clamp for flow control, filled with a solution (1/3 water, 1/3 glycerin, 1/3 alcohol) simulating blood viscosity and density. Flow-versus-pressure curves were obtained for rotational speeds of 1000, 1500, 2000, 2500, and 3000 rpm. As the next step, the CFD analysis and hydrodynamic performance results will be compared with the results of flow visualization studies and hemolysis tests. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  14. The influence of assistive technology devices on the performance of activities by visually impaired

    Directory of Open Access Journals (Sweden)

    Suzana Rabello

    2014-04-01

    Full Text Available Objective: To establish the influence of assistive technology devices (ATDs on the performance of activities by visually impaired schoolchildren in the resource room. Methods: A qualitative study that comprised observation and an educational intervention in the resource room. The study population comprised six visually impaired schoolchildren aged 12 to 14 years old. The participants were subjected to an eye examination, prescribed ATDs comprising optical and non-optical devices, and provided an orientation on the use of computers. The participants were assessed based on eye/object distance, font size, and time to read a computer screen and printed text. Results: The ophthalmological conditions included corneal opacity, retinochoroiditis, retinopathy of prematurity, aniridia, and congenital cataracts. Far visual acuity varied from 20/200 to 20/800 and near visual acuity from 0.8 to 6 M. Telescopes, spherical lenses, and support magnifying glasses were prescribed. Three out of five participants with low vision after intervention could decrease the font size on the screen computer, and most participants (83.3% reduced their reading time at the second observation session. Relative to the printed text, all the participants with low vision were able to read text written in smaller font sizes and reduced their reading time at the second observation session. Conclusion: Reading skills improved after the use of ATDs, which allowed the participants to perform their school tasks equally to their classmates.

  15. Molecular changes after left ventricular assist device support for heart failure.

    Science.gov (United States)

    Birks, Emma J

    2013-08-30

    Heart failure is associated with remodeling that consists of adverse cellular, structural, and functional changes in the myocardium. Until recently, this was thought to be unidirectional, progressive, and irreversible. However, irreversibility has been shown to be incorrect because complete or partial reversal can occur that can be marked after myocardial unloading with a left ventricular assist device (LVAD). Patients with chronic advanced heart failure can show near-normalization of nearly all structural abnormalities of the myocardium or reverse remodeling after LVAD support. However, reverse remodeling does not always equate with clinical recovery. The molecular changes occurring after LVAD support are reviewed, both those demonstrated with LVAD unloading alone in patients bridged to transplantation and those occurring in the myocardium of patients who have recovered enough myocardial function to have the device removed. Reverse remodeling may be attributable to a reversal of the pathological mechanisms that occur in remodeling or the generation of new pathways. A reduction in cell size occurs after LVAD unloading, which does not necessarily correlate with improved cardiac function. However, some of the changes in both the cardiac myocyte and the matrix after LVAD support are specific to myocardial recovery. In the myocyte, increases in the cytoskeletal proteins and improvements in the Ca²⁺ handling pathway seem to be specifically associated with myocardial recovery. Changes in the matrix are complex, but excessive scarring appears to limit the ability for recovery, and the degree of fibrosis in the myocardium at the time of implantation may predict the ability to recover.

  16. HeartWare Ventricular Assist Device Implantation in Patients With Fontan Physiology.

    Science.gov (United States)

    Imielski, Bartlomiej R; Niebler, Robert A; Kindel, Steven J; Woods, Ronald K

    2017-01-01

    We aim to describe the clinical course of a series of patients with hypoplastic left heart syndrome and refractory systolic heart failure supported with a HeartWare ventricular assist device (HVAD) following Fontan palliation. This is a retrospective review of three consecutive patients supported with a HVAD following Fontan palliation through February 2016. Data include patient characteristics, operative variables, postimplantation hemodynamic/device parameters, event outcomes, and duration of HVAD support. Patient ages were 11.7, 13.5, and 17.5 years, respectively, at the time of HVAD implant. The duration of HVAD support was 148, 272, and 271 days, respectively, of which 86, 222, and 211 were outpatient days. Inflow cannula position was the morphologic right ventricle with depth adjustment and manipulation of the tricuspid subvalvar apparatus to ensure good inflow. Echocardiographic, hemodynamic, and noninvasive oximetric monitoring resulted in high RPM settings for all patients. Despite various complications, all patients were successfully transplanted and discharged home alive. We present three patients bridged to transplantation using the HVAD following Fontan palliation. We demonstrate potential for durable support with transition to outpatient care while awaiting heart transplantation in a subset of patients status post Fontan surgery. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Optimization of the Outflow Graft Position and Angle in a Left Ventricular Assist Device

    Science.gov (United States)

    McGah, Patrick; Prisco, Anthony; Beckman, Jennifer; Mokadam, Nahush; Mahr, Claudius; Aliseda, Alberto

    2015-11-01

    The placement of the outflow graft in the aorta plays a key role in the hemodynamics of Left Ventricle Assist Devices (LVAD), a medical device with a growing importance in the treatment of end-stage heart failure. We use a patient-specific computational model of the VAD and the ascending aorta to investigate the impact of VAD outflow graft configuration on the residence time and wall shear stresses along the ascending aorta and the ostia of the upper branches. The flow induced by the combination of VAD output through the graft anastomosed to the aorta and the limited cardiac output through intermittent opening of the aortic valve is studied to determine the nature of thrombogenic flow patterns. Outflow grafts are virtually anastomosed along the ascending aorta or subclavian artery of the patient-specific model at different positions and angles that are surgically-informed. Detailed markers of thrombosis, such as cell residence time, wall shear stress, and shear stress gradients are analyzed and compared for the different configurations. The angle of incidence of the outflow graft critically influences the volume of recirculating flow between aortic valve and anastomosis, and the aortic pressure acting against aortic valve opening.

  18. Development of a fixation device for robot assisted fracture reduction of femoral shaft fractures: a biomechanical study.

    Science.gov (United States)

    Weber-Spickschen, T S; Oszwald, M; Westphal, R; Krettek, C; Wahl, F; Gosling, T

    2010-01-01

    Robot assisted fracture reduction of femoral shaft fractures provides precise alignment while reducing the amount of intraoperative imaging. The connection between the robot and the fracture fragment should allow conventional intramedullary nailing, be minimally invasive and provide interim fracture stability. In our study we tested three different reduction tools: a conventional External Fixator, a Reposition-Plate and a Three-Point-Device with two variations (a 40 degrees and a 90 degrees version). We measured relative movements between the tools and the bone fragments in all translation and rotation planes. The Three-Point-Device 90 degrees showed the smallest average relative displacement and was the only device able to withstand the maximum applied load of 70 Nm without failure of any bone fragment. The Three-Point-Device 90 degrees complies with all the stipulated requirements and is a suitable interface for robot assisted fracture reduction of femoral shaft fractures.

  19. A review of assistive listening device and digital wireless technology for hearing instruments.

    Science.gov (United States)

    Kim, Jin Sook; Kim, Chun Hyeok

    2014-12-01

    Assistive listening devices (ALDs) refer to various types of amplification equipment designed to improve the communication of individuals with hard of hearing to enhance the accessibility to speech signal when individual hearing instruments are not sufficient. There are many types of ALDs to overcome a triangle of speech to noise ratio (SNR) problems, noise, distance, and reverberation. ALDs vary in their internal electronic mechanisms ranging from simple hard-wire microphone-amplifier units to more sophisticated broadcasting systems. They usually use microphones to capture an audio source and broadcast it wirelessly over a frequency modulation (FM), infra-red, induction loop, or other transmission techniques. The seven types of ALDs are introduced including hardwire devices, FM sound system, infra-red sound system, induction loop system, telephone listening devices, television, and alert/alarm system. Further development of digital wireless technology in hearing instruments will make possible direct communication with ALDs without any accessories in the near future. There are two technology solutions for digital wireless hearing instruments improving SNR and convenience. One is near-field magnetic induction combined with Bluetooth radio frequency (RF) transmission or proprietary RF transmission and the other is proprietary RF transmission alone. Recently launched digital wireless hearing aid applying this new technology can communicate from the hearing instrument to personal computer, phones, Wi-Fi, alert systems, and ALDs via iPhone, iPad, and iPod. However, it comes with its own iOS application offering a range of features but there is no option for Android users as of this moment.

  20. A Review of Assistive Listening Device and Digital Wireless Technology for Hearing Instruments

    Science.gov (United States)

    Kim, Chun Hyeok

    2014-01-01

    Assistive listening devices (ALDs) refer to various types of amplification equipment designed to improve the communication of individuals with hard of hearing to enhance the accessibility to speech signal when individual hearing instruments are not sufficient. There are many types of ALDs to overcome a triangle of speech to noise ratio (SNR) problems, noise, distance, and reverberation. ALDs vary in their internal electronic mechanisms ranging from simple hard-wire microphone-amplifier units to more sophisticated broadcasting systems. They usually use microphones to capture an audio source and broadcast it wirelessly over a frequency modulation (FM), infra-red, induction loop, or other transmission techniques. The seven types of ALDs are introduced including hardwire devices, FM sound system, infra-red sound system, induction loop system, telephone listening devices, television, and alert/alarm system. Further development of digital wireless technology in hearing instruments will make possible direct communication with ALDs without any accessories in the near future. There are two technology solutions for digital wireless hearing instruments improving SNR and convenience. One is near-field magnetic induction combined with Bluetooth radio frequency (RF) transmission or proprietary RF transmission and the other is proprietary RF transmission alone. Recently launched digital wireless hearing aid applying this new technology can communicate from the hearing instrument to personal computer, phones, Wi-Fi, alert systems, and ALDs via iPhone, iPad, and iPod. However, it comes with its own iOS application offering a range of features but there is no option for Android users as of this moment. PMID:25566400

  1. Exercise capacity in left ventricular assist device patients with full and partial support.

    Science.gov (United States)

    Fresiello, Libera; Buys, Roselien; Jacobs, Steven; Van Puyvelde, Joeri; Droogne, Walter; Rega, Filip; Meyns, Bart

    2017-01-01

    Background In the present work, we investigated the exercise capacities of patients with partial flow left ventricular assist devices and its evolution over time. We then compared the exercise capacities of these patients with those of full support ventricular assist device patients. Methods We retrospectively analysed the data of maximal cardiopulmonary exercise tests of ten partial support patients (CircuLite Synergy® Micropump) collected before (PS0), at 3 (PS3) and 6 months (PS6) after implantation. The data were then compared with those of 17 patients (FS6) treated with a full support device (HeartMate II, Thoratec©). For this analysis, we considered the exercise tests performed at 6 months after pump implantation for both groups. Results Peak oxygen uptake evolved in the PS0, PS3 and PS6 groups from 11.5 ± 2.3 to 12.6 ± 2.8 and 12.0 ± 2.7 mL/kg/min, respectively. Heart rate peak increased from PS0 to PS6 (100 ± 17 bpm and 107 ± 22 bpm, p = 0.05). The comparative analysis between PS6 and FS6 groups showed no difference in terms of exercise performance (12.0 ± 2.7 and 13.5 ± 3.0 mL/kg/min, respectively), fatigue perception, ventilation efficiency slope, anaerobic threshold and oxygen uptake efficiency slope. The chronotropic response was also similar in both PS6 and FS6 groups. However, PS6 patients were more often treated with β-blockers and therefore had lower heart rates at rest and at peak exercise than FS6 patients. Conclusions Exercise performance does not change after partial support implantation and stays stable over time. Partial and full support patients show similar exercise performances that attain 41% and 46% of the expected values, respectively.

  2. Left Ventricular Assist Devices for Destination Therapy: A Health Technology Assessment

    Science.gov (United States)

    2016-01-01

    Background Left ventricular assist devices (LVADs) provide circulatory support to assist the damaged left ventricle in patients with end-stage heart failure. Implantation of an LVAD is sometimes a last resort for patients with end stage heart failure who are ineligible for heart transplantation (destination therapy). First-generation LVADs used pulsatile pumps to mimic the natural pulsing action of the heart. Implanted second-generation LVADs use a rapidly spinning rotor to produce a continuous flow of blood into the systemic arterial system. Objectives Our objectives were to: Determine the clinical effectiveness of LVADs for destination therapy for patients with end-stage heart failure who are ineligible for heart transplantation Estimate the cost-effectiveness of destination-therapy LVAD for patients with end-stage heart failure who are ineligible for heart transplantation and to estimate the potential budget impact for the Ontario Ministry of Health and Long-Term Care over the next 5 years Methods We performed a narrative review of the clinical and economic literature for effectiveness and cost-effectiveness and a budget impact analysis from the perspective of the Ministry of Health and Long-Term Care. We did not conduct a meta-analysis of the clinical evidence owing to differences in the type of LVADs included in the studies. Results Three systematic reviews and one observational study contributed to the clinical evidence. Three economic reviews contributed to the economic evidence. There is moderate quality evidence that treatment with continuous-flow LVADs improves survival but has higher adverse events rates compared with drug therapy. Low quality evidence suggests treatment with a continuous-flow LVADs improves quality of life. The incremental cost-effectiveness ratio associated with destination-therapy LVAD over optimal medical management is relatively high and exceeds the traditionally accepted thresholds ($50,000 to $100,000 per quality-adjusted life

  3. Flow Visualization of Three-Dimensionality Inside the 12 cc Penn State Pulsatile Pediatric Ventricular Assist Device

    OpenAIRE

    Roszelle, Breigh N.; Deutsch, Steven; Manning, Keefe B.

    2010-01-01

    In order to aid the ongoing concern of limited organ availability for pediatric heart transplants, Penn State has continued development of a pulsatile Pediatric Ventricular Assist Device (PVAD). Initial studies of the PVAD observed an increase in thrombus formation due to differences in flow field physics when compared to adult sized devices, which included a higher degree of three-dimensionality. This unique flow field brings into question the use of 2D planar particle image velocimetry (PIV...

  4. Loose-Lipped Mobile Device Intelligent Personal Assistants: A Discussion of Information Gleaned from Siri on Locked iOS Devices.

    Science.gov (United States)

    Horsman, Graeme

    2018-04-23

    The forensic analysis of mobile handsets is becoming a more prominent factor in many criminal investigations. Despite such devices frequently storing relevant evidential content to support an investigation, accessing this information is becoming an increasingly difficult task due to enhanced effective security features. Where access to a device's resident data is not possible via traditional mobile forensic methods, in some cases it may still be possible to extract user information via queries made to an installed intelligent personal assistant. This article presents an evaluation of the information which is retrievable from Apple's Siri when interacted with on a locked iOS device running iOS 11.2.5 (the latest at the time of testing). The testing of verbal commands designed to elicit a response from Siri demonstrate the ability to recover call log, SMS, Contacts, Apple Maps, Calendar, and device information which may support any further investigation. © 2018 American Academy of Forensic Sciences.

  5. Ramp Study Hemodynamics, Functional Capacity, and Outcome in Heart Failure Patients with Continuous-Flow Left Ventricular Assist Devices

    DEFF Research Database (Denmark)

    Jung, Mette H; Gustafsson, Finn; Houston, Brian

    2016-01-01

    Ramp studies-measuring changes in cardiac parameters as a function of serial pump speed changes (revolutions per minute [rpm])-are increasingly used to evaluate function and malfunction of continuous-flow left ventricular assist devices (CF-LVADs). We hypothesized that ramp studies can predict fu...

  6. The provision of assistive devices and home adaptations to patients with ALS in the Netherlands: patients' perspectives

    NARCIS (Netherlands)

    Creemers, Huub; Beelen, Anita; Grupstra, Hepke; Nollet, Frans; van den Berg, Leonard H.

    2014-01-01

    The timely provision of assistive devices and home adaptations (ADHA) is crucial in the management of patients with amyotrophic lateral sclerosis (ALS) in order to maintain their independence and relieve their caregivers. Our objective was to study the experiences of patients with ALS during the

  7. The possession of assistive devices is related to improved psychological well-being in patients with rheumatic conditions

    NARCIS (Netherlands)

    Veehof, M.M.; Taal, Erik; Rasker, Johannes J.; Lohmann, Johannes; van de Laar, Mart A F J

    2006-01-01

    OBJECTIVE: To investigate the relationship between the possession of assistive devices and psychological well-being in patients with rheumatic conditions. METHODS: Patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) were selected from rheumatology outpatient clinics in 2 adjacent

  8. Atrophy of the Heart After Insertion of a Left Ventricular Assist Device and Closure of the Aortic Valve.

    Science.gov (United States)

    Roberts, William C; Hall, Shelley A; Ko, Jong M; McCullough, Peter A; Lima, Brian

    2016-03-01

    Described are findings in a 70-year-old man who had heart transplantation 4 years after treatment with a left ventricular assist device, and surgical closure of his previously replaced aortic valve. The result was a totally nonfunctioning left ventricle resulting in severe atrophy. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Influence of dilated cardiomyopathy and a left ventricular assist device on vortex dynamics in the left ventricle

    NARCIS (Netherlands)

    Loerakker, S.; Cox, L. G. E.; van Heijst, G. J. F.; de Mol, B. A. J. M.; van de Vosse, F. N.

    2008-01-01

    Together with new developments in mechanical cardiac support, the analysis of vortex dynamics in the left ventricle has become an increasingly important topic in literature. The aim of this study was to develop a method to investigate the influence of a left ventricular assist device (LVAD) on

  10. Nipro extra-corporeal left ventricular assist device fitting after left ventricular reconstruction with mitral valve plasty.

    Science.gov (United States)

    Arakawa, Mamoru; Yamaguchi, Atsushi; Nishimura, Takashi; Itoh, Satoshi; Yuri, Koichi; Kyo, Shunei; Adachi, Hideo

    2015-12-01

    Both left ventricular assist device and left ventricular reconstruction are treatment choices for severe heart failure conditions. Our institution performed a left ventricular assist device installation following a left ventricular reconstruction procedure on a 42-year-old male patient who presented with dilated cardiomyopathy and low cardiac output syndrome. A mitral valve plasty was used to correct the acute mitral valve regurgitation and we performed a Nipro extra-corporeal left ventricular assist device installation on post-operative day 14. Due to the left ventricular reconstruction that the patient had in a previous operation, we needed to attach an apical cuff on posterior apex, insert the inflow cannula with a large curve, and shift the skin insertion site laterally to the left. We assessed the angle between the cardiac longitudinal axis and the inflow cannula using computed tomography. The patient did not complain of any subjective symptoms of heart failure. Although Nipro extra-corporeal left ventricular assist device installation after left ventricular reconstruction has several difficulties historically, we have experienced a successful case.

  11. The Use of Pediatric Ventricular Assist Devices in Children's Hospitals From 2000 to 2010: Morbidity, Mortality, and Hospital Charges.

    Science.gov (United States)

    Mansfield, Robert T; Lin, Kimberly Y; Zaoutis, Theoklis; Mott, Antonio R; Mohamad, Zeinab; Luan, Xianqun; Kaufman, Beth D; Ravishankar, Chitra; Gaynor, J William; Shaddy, Robert E; Rossano, Joseph W

    2015-07-01

    The use of ventricular assist devices has increased dramatically in adult heart failure patients. However, the overall use, outcome, comorbidities, and resource utilization of ventricular assist devices in pediatric patients have not been well described. We sought to demonstrate that the use of ventricular assist devices in pediatric patients has increased over time and that mortality has decreased. A retrospective study of the Pediatric Health Information System database was performed for patients 20 years old or younger undergoing ventricular assist device placement from 2000 to 2010. None. Four hundred seventy-five pediatric patients were implanted with ventricular assist devices during the study period: 69 in 2000-2003 (era 1), 135 in 2004-2006 (era 2), and 271 in 2007-2010 (era 3). Median age at ventricular assist device implantation was 6.0 years (interquartile range, 0.5-13.8), and the proportion of children who were 1-12 years old increased from 29% in era 1 to 47% in era 3 (p = 0.002). The majority of patients had a diagnosis of cardiomyopathy; this increased from 52% in era 1 to 72% in era 3 (p = 0.003). Comorbidities included arrhythmias (48%), pulmonary hypertension (16%), acute renal failure (34%), cerebrovascular disease (28%), and sepsis/systemic inflammatory response syndrome (34%). Two hundred forty-seven patients (52%) underwent heart transplantation and 327 (69%) survived to hospital discharge. Hospital mortality decreased from 42% in era 1 to 25% in era 3 (p = 0.004). Median hospital length of stay increased (37 d [interquartile range, 12-64 d] in era 1 vs 69 d [interquartile range, 35-130] in era 3; p interquartile range, $227,052-$853,318] in era 1 vs $1,577,983 [interquartile range, $874,463-$2,280,435] in era 3; p < 0.001). Factors associated with increased mortality include age less than 1 year (odds ratio, 2.04; 95% CI, 1.01-3.83), acute renal failure (odds ratio, 2.1; 95% CI, 1.26-3.65), cerebrovascular disease (odds ratio, 2.1; 95% CI, 1

  12. Development of an inlet pressure sensor for control in a left ventricular assist device.

    Science.gov (United States)

    Fritz, Bryan; Cysyk, Joshua; Newswanger, Ray; Weiss, William; Rosenberg, Gerson

    2010-01-01

    A Tesla type continuous flow left ventricular assist device (VAD) has been designed by Penn State and Advanced Bionics, Inc. (ABI). When a continuous flow device is used, care must be taken to limit low pressures in the ventricle, which can produce an obstruction to the inlet cannula or trigger arrhythmias. Design of an inexpensive, semiconductor strain gauge inlet pressure sensor to detect suction has been completed. The research and design analysis included finite element modeling of the sensing region. Sensitivity, step-response, temperature dependence, and hysteresis tests have been performed on prototype units. All sensors were able to withstand the maximum expected strain of 82 microm/in at 500 mm Hg internal pressure. Average sensitivity was 0.52 +/- 0.24 microV/mm Hg with 0.5 V excitation (n = 5 units). Step-response time for a 0- to 90-mm Hg step change averaged 22 msec. Hysteresis was measured by applying and holding 75 mm Hg internal pressure for 4 hours, followed by a zero pressure measurement, and ranged from -15 to 4.1 mm Hg (n = 3 units). Offset drift varied between 180 and -140 mm Hg over a 4-week period (n = 2 units). Span temperature sensitivity ranged from 18 to -21 muV/ degrees C (n = 5 units). Gain temperature sensitivity ranged from -7.4 to 4.9 muV/ degrees C (n = 5 units). With the inherent drift, it is currently not possible to use the transducer to measure actual pressures, but it can easily be used to measure pressure changes throughout the cardiac cycle. This signal can then be used in the control system to avoid ventricular suction events.

  13. Left ventricular assist devices and gastrointestinal bleeding: a narrative review of case reports and case series.

    Science.gov (United States)

    Islam, Sameer; Cevik, Cihan; Madonna, Rosalinda; Frandah, Wesam; Islam, Ebtesam; Islam, Sherazad; Nugent, Kenneth

    2013-04-01

    The use of left ventricular assist devices (LVADs) has become a state-of-the-art therapy for advanced cardiac heart failure; however, multiple reports in the literature describe an increased risk for gastrointestinal (GI) bleeding in these patients. We characterized this association by reviewing recent studies on this topic. GI bleeding occurs frequently in patients with LVADs, especially with devices with nonpulsatile flow patterns. We performed a comprehensive literature review to identify articles that reported GI bleeding in patients with LVADs. Databases used included PubMed, EMBASE, Scopus, Web of Knowledge, and Ovid. Baseline and outcome data were then ed from these reports. We identified 10 case reports and 22 case series with 1543 patients. The mean age was 54.2 years. Most patients had nonpulsatile LVADs (1316, 85.3%). Three hundred and seventeen patients (20.5%) developed GI bleeding; this occurred more frequently in patients with nonpulsatile LVADs. Multiple procedures were performed without complications but often did not identify a definite bleeding site. Suspect lesions occurred throughout the GI tract but were more frequent in the upper GI tract. Many patients had arteriovenous malformations. All patients received medical therapy. None of the patients had their LVAD replaced. The use of anticoagulation did not appear to predispose these patients to more GI bleeding episodes. Patients with LVADs have frequent GI bleeds, especially from arteriovenous malformations, which can occur throughout the GI tract. Most diagnostic and therapeutic interventions can be used safely in these patients. The pathogenesis of the GI bleeding in these patients may involve the use of anticoagulant medications, the formation of arteriovenous malformations, loss of von Willebrand factor activity, and mucosal ischemia. © 2013 Wiley Periodicals, Inc.

  14. Heart monitoring using left ventricle impedance and ventricular electrocardiography in left ventricular assist device patients.

    Science.gov (United States)

    Her, Keun; Ahn, Chi Bum; Park, Sung Min; Choi, Seong Wook

    2015-03-21

    Patients who develop critical arrhythmia during left ventricular assist device (LVAD) perfusion have a low survival rate. For diagnosis of unexpected heart abnormalities, new heart-monitoring methods are required for patients supported by LVAD perfusion. Ventricular electrocardiography using electrodes implanted in the ventricle to detect heart contractions is unsuitable if the heart is abnormal. Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle. To detect detailed abnormal heart conditions, we obtained ventricular electrocardiograms (v-ECGs) and LVI simultaneously in porcine models connected to LVADs. In the porcine models, electrodes were set on the heart apex and ascending aorta for real-time measurements of v-ECGs and LVI. As the carrier current frequency of the LVI was adjusted to 30 kHz, it was easily derived from the original v-ECG signal by using a high-pass filter (cutoff: 10 kHz). In addition, v-ECGs with a frequency band of 0.1 - 120 Hz were easily derived using a low-pass filter. Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted. A new real-time algorithm for comparison of v-ECGs and LVI determined whether the porcine heartbeats were normal or abnormal. Several abnormal heartbeats were detected using the LVADs operating in asynchronous mode, most of which were premature ventricle contractions (PVCs). To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices. The new method provided more accurate detection of abnormal heart movements. This method can be used for various heart diseases, even those in which the cardiac output is heavily affected by LVAD operation.

  15. Right heart failure and "failure to thrive" after left ventricular assist device: clinical predictors and outcomes.

    Science.gov (United States)

    Baumwol, Jay; Macdonald, Peter S; Keogh, Anne M; Kotlyar, Eugene; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

    2011-08-01

    This study determined predictors of early post-operative right heart failure (RHF) and its consequences, as well as predictors of those who clinically thrive longer term after insertion of a continuous-flow left ventricular assist device (LVAD). Pre-operative and latest follow-up data were analyzed for 40 consecutive patients who received third-generation centrifugal-flow LVADs. RHF was defined using previously described criteria, including post-operative inotropes, pulmonary vasodilator use, or right-sided mechanical support. Patients were also categorized according to clinical outcomes after LVAD insertion. LVADs were implanted as a bridge to transplantation (BTT) in 33 patients and as destination therapy in 7. Before LVAD implant, 22 patients were Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level 1, and 17 were at level 2. Temporary mechanical assistance was present in 50% of the cohort at LVAD implantation. The 6-month survival/progression to transplant was 92.5%. Average LVAD support time was 385 days (range, 21-1,011 days). RHF developed postoperatively in 13 of 40 patients (32.5%). RHF patients had more severe pre-operative tricuspid incompetence than non-RHF patients. The BTT patients with evidence of RHF had poorer survival to transplant (6 of 11 [54.5%]) than those without RHF (20 of 22 [90.9%]), p = 0.027). There were no other hemodynamic or echocardiographic predictors of short-term RHF. After LVAD, 22 of the 40 patients (55%) thrived clinically. For BTT patients, 20 of 21 (95%) of those who thrived progressed to transplant or were alive at latest follow-up vs 6 of 12 (50%) of those who failed to thrive (FTT; p thrived. Early post-operative RHF results in poorer survival/progression to transplantation for BTT patients and is predicted by greater pre-operative tricuspid incompetence. The most important predictor for those who will clinically thrive longer-term after LVAD insertion is younger age. Crown Copyright © 2011

  16. Feasibility of Home-Use Animal-Assisted Activities in Patients With Implanted Cardiac Electronic Devices

    Directory of Open Access Journals (Sweden)

    Peter Jirak

    2016-02-01

    Full Text Available Animal-assisted activities (AAAs are mainly carried out in institutions. The aim of this prospective pilot study was to assess the willingness of patients with cardiac implanted electronic devices (IEDs to participate in AAA. The sample included 75 ambulatory patients (18 females, M age = 69 years, who attended an outpatient clinic for control of antibradycardic pacemakers (n = 15 or implanted cardioverter defibrillators (n = 60. Twenty-three percent were current and 48% were previous pet-owners. Current pet-owners were younger than non-pet-owners (63.5 vs. 72.0 years, p = .0003. Twelve patients (16% showed interest in AAA visits. However, only two patients agreed to an AAA visit. Both patients were visited once, but declined further visits. Hence, AAA sessions at home were poorly accepted, mainly because the patients considered themselves too busy or healthy, or due to a general disinterest in AAA. Potential health benefits associated with AAA may not be feasible to investigate during home visits of AAA-teams in patients with IEDs who are healthy enough to leave their homes. For further studies concerning AAA in patients with cardiovascular diseases, we suggest focusing on institutions like rehabilitation centers or day care centers and on more severely sick, homebound patients.

  17. Implant Strategy-Specific Changes in Symptoms in Response to Left Ventricular Assist Devices.

    Science.gov (United States)

    Lee, Christopher S; Gelow, Jill M; Chien, Christopher V; Hiatt, Shirin O; Bidwell, Julie T; Denfeld, Quin E; Grady, Kathleen L; Mudd, James O

    Although we know that the quality of life generally improves after left ventricular assist device (LVAD) implantation, we know little about how symptoms change in response to LVAD. The purpose of this study was to compare the changes in symptoms between bridge and destination therapy patients as part of a prospective cohort study. Physical (dyspnea and wake disturbances) and affective symptoms (depression and anxiety) were measured before LVAD and at 1, 3, and 6 months after LVAD. Multiphase growth modeling was used to capture the 2 major phases of change: initial improvements between preimplant and 1 month after LVAD and subsequent improvements between 1 and 6 months after LVAD. The sample included 64 bridge and 22 destination therapy patients as the preimplant strategy. Destination patients had worse preimplant dyspnea and wake disturbances, and they experienced greater initial improvements in these symptoms compared with bridge patients (all P .05). Destination patients had worse preimplant depression (P = .042) but experienced similar initial and subsequent improvements in depression in response to LVAD compared with bridge patients (both P > .05). Destination patients had similar preimplant anxiety (P = .279) but experienced less initial and greater subsequent improvements in anxiety after LVAD compared with bridge patients (both P < .05). There are many differences in the magnitude and timing of change in symptom responses to LVAD between bridge and destination therapy patients. Detailed information on changes in specific symptoms may better inform shared decision-making regarding LVAD.

  18. Ventricular Energetics in Pediatric Left Ventricular Assist Device Patients: A Retrospective Clinical Study.

    Science.gov (United States)

    Di Molfetta, Arianna; Ferrari, Gianfranco; Iacobelli, Roberta; Filippelli, Sergio; Di Chiara, Luca; Guccione, Paolo; Amodeo, Antonio

    The aim of this study is to estimate the trend of right and left energetic parameters in left ventricular assist device (LVAD) pediatric patients. Echocardiographic data were retrospectively collected at the baseline, in the acute phase after and at the monthly follow-ups till the LVAD explantation to estimate left and right ventricular energetic parameters. A significant relationship between the left and right ventricular energetic parameter trends was found along all the study period. Left ventricular end-systolic pressure-volume relationship improved till the follow-up of 2 months and then progressively decreases. Left arteroventricular coupling decreases after the LVAD, and right arteroventricular coupling decreases at the short-term follow-up. Left ventricular external work, potential energy, and pressure-volume area decrease at the short-term follow-up and then increase progressively. Right ventricular external work, potential energy, and pressure-volume area increase after the LVAD implantation. Left (right) cardiac mechanical efficiency is improved (worsened) by the LVAD. Energetic variables show that the LVAD benefits could decrease over time. A continuous and patient tailored LVAD setting could contribute to prolong LVAD benefits. The introduction of energetic parameters could lead to a more complete evaluation of LVAD patients' outcome which is a multiparametric process.

  19. Evaluation of gait performance of knee osteoarthritis patients after total knee arthroplasty with different assistive devices

    Directory of Open Access Journals (Sweden)

    Ana Tereso

    Full Text Available IntroductionNowadays Knee Osteoarthritis (KOA affects a large percentage of the elderly, and one solution is to perform a Total Knee Arthroplasty (TKA. In this paper, one intends to study the gait and posture of these patients after the TKA, while walking with three assistive devices (ADs (crutches, standard walker (SW and rollator with forearm supports (RFS.MethodsEleven patients were evaluated in 2 phases: 5 days and 15 days after surgery. This evaluation was conducted with two inertial sensors, one attached to the operated leg ankle, to measure spatiotemporal parameters, and the other at the sacrum, to measure posture and fall risk-related parameters. Multivariate analysis of variance (MANOVA with repeated measures was performed to detect group differences.ResultsThe MANOVA results show that all spatiotemporal parameters are significantly different (p0.05. The interaction between time and ADs only affects significantly the velocity (p<0.05. In terms of fall risk parameters, time only significantly affects the antero-posterior direction (p<0.05 and ADs affects significantly root mean square in medio-lateral direction (p<0.05. In terms of interaction between time and ADs, there are no statistical significant differences.ConclusionThis study concludes that depending on the state of recovery of the patient, different ADs should be prescribed. On the overall, standard walker is good to give stability to the patient and RFS allows the patient to present a gait pattern closer to a natural gait.

  20. Anesthesia for left ventricular assist device insertion: a case series and review.

    Science.gov (United States)

    Broussard, David; Donaldson, Emilie; Falterman, Jason; Bates, Michael

    2011-01-01

    From October 2008 to June 2010, a total of 42 patients had the HeartMate II left ventricular assist device inserted surgically at Ochsner Medical Center in New Orleans, LA. A retrospective electronic record review was conducted on this series of patients to analyze elements of perioperative anesthetic care, including general anesthetic care, echocardiographic considerations, and blood product usage. Etomidate was used to induce anesthesia for 34 of 42 patients (81%) in this series, with an average dose of 16.5 mg (±6 mg). The average intraoperative fentanyl dose was 1,318 µg (±631 µg). On average, patients were extubated 91 hours (±72 hours) after arrival to the intensive care unit and left on day 9 (±5 days). The average left ventricular ejection fraction of the patients in this series was 13% (±5%). Sixteen patients were evaluated as having severe right-heart dysfunction preoperatively. Two of 42 patients required surgical closure of echocardiographically identified patent foramen ovale. Twelve of 42 patients underwent surgical correction of tricuspid regurgitation. On average, 3 units (±2.6 units) of fresh frozen plasma were transfused intraoperatively and 10 units postoperatively. Intraoperative red blood cell usage averaged 1.1 units (maximum, 7 units), with an average 9.3 units administered in the first 48 hours postoperatively.

  1. Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

    Science.gov (United States)

    Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

    2017-05-01

    Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  2. Identification of non-HLA antibodies in ventricular assist device recipients

    Directory of Open Access Journals (Sweden)

    Sandy von Salisch

    2013-11-01

    Full Text Available Aims Recipients of ventricular assist devices (VADR have a higher incidence to develop antibodies (Abs against human leukocyte antigens (HLA. Non-HLA antibodies like major histocompatibility complex class I-related chain A (MICA and autoantibodies against angiotensin type 1 receptor (AT1R and endothelin receptor A (ETAR are also implicated in the pathogenesis of acute rejection and allograft vasculopathy. We monitored non-HLA- and HLA-Abs in VADR up to one year after implantation. Materials and methods Sera of 56 VADR (54.1±12.8 years old, 50 men were analyzed for Abs against HLA-, MICA-, AT1R- and ETAR several times over one year after implantation using ELISA and Luminex xMAP technology. Blood transfusions, gender and age were reviewed. Results Sera of 56 VADR (54.1±12.8 years old, 50 men were analyzed for Abs against HLA-, MICA-, AT1R- and ETAR several times over one year after implantation using ELISA and Luminex xMAP technology. Blood transfusions, gender and age were reviewed. Conclusion Beside HLA- and MICA-Abs, VADR showed high titres of Abs against AT1R or ETAR, which underlines the necessity for monitoring non-HLA antibodies in VADR prior heart transplantation.

  3. Thresholds of physical activity and life expectancy for patients considering destination ventricular assist devices.

    Science.gov (United States)

    Stewart, Garrick C; Brooks, Kimberly; Pratibhu, Parakash P; Tsang, Sui W; Semigran, Marc J; Smith, Colleen M; Saniuk, Catherine; Camuso, Janice M; Fang, James C; Mudge, Gilbert H; Couper, Gregory S; Baughman, Kenneth L; Stevenson, Lynne W

    2009-09-01

    Current implantable left ventricular assist devices (LVAD) improve survival and function for patients with very late stage heart failure (HF) but may also offer benefit before inotrope dependence. Debate continues about selection of HF patients for LVAD therapy. We sought to determine what level of personal risk and disability HF patients thought would warrant LVAD therapy. The study included 105 patients with symptomatic HF and an LV ejection fraction (EF) trade-off utility, and patient-assessed functional score were determined. Participants (mean age, 58 years) had an LVEF of 21%. The median duration of HF was 5 years, and 65% had a primary prevention implantable cardioverter defibrillator. Presented with a scenario of bed-ridden HF, 81% stated they would definitely or probably want an LVAD; 50% would consider LVAD to prolong survival if HF survival were predicted to be dress without stopping. Anticipated thresholds did not differ by NYHA class, time trade-off, or functional score. Patient thresholds for LVAD insertion parallel objective survival and functional data. HF patients would be receptive to referral for discussion of LVAD by the time expected mortality is within 6 to 12 months and activity remains limited to less than 1 block.

  4. Developments in control systems for rotary left ventricular assist devices for heart failure patients: a review

    International Nuclear Information System (INIS)

    AlOmari, Abdul-Hakeem H; Savkin, Andrey V; Lovell, Nigel H; Stevens, Michael; Mason, David G; Timms, Daniel L; Salamonsen, Robert F

    2013-01-01

    From the moment of creation to the moment of death, the heart works tirelessly to circulate blood, being a critical organ to sustain life. As a non-stopping pumping machine, it operates continuously to pump blood through our bodies to supply all cells with oxygen and necessary nutrients. When the heart fails, the supplement of blood to the body's organs to meet metabolic demands will deteriorate. The treatment of the participating causes is the ideal approach to treat heart failure (HF). As this often cannot be done effectively, the medical management of HF is a difficult challenge. Implantable rotary blood pumps (IRBPs) have the potential to become a viable long-term treatment option for bridging to heart transplantation or destination therapy. This increases the potential for the patients to leave the hospital and resume normal lives. Control of IRBPs is one of the most important design goals in providing long-term alternative treatment for HF patients. Over the years, many control algorithms including invasive and non-invasive techniques have been developed in the hope of physiologically and adaptively controlling left ventricular assist devices and thus avoiding such undesired pumping states as left ventricular collapse caused by suction. In this paper, we aim to provide a comprehensive review of the developments of control systems and techniques that have been applied to control IRBPs. (topical review)

  5. Children at home on mechanical assistive devices and their families: a retrospective study.

    Science.gov (United States)

    Williams, P D; Williams, A R; Griggs, C

    1990-01-01

    Few assessments have been done of the influence of caregiver and family interactions on the developmental status of children discharged on mechanical assistive devices. The ages of the 25 children in this study ranged from 2-30 months. Seven were on apnea monitors at the time of the home interviews, and 18 had been off the monitors for 18 months or more. Mothers were administered six questionnaires: Family Adaptability and Cohesion Evaluation Scales (FACES III), Duke-UNC Functional Social Support Questionnaire, Families Coping Strategies (FCOPES), Self-Esteem Scale, Home Observation for Measurement of the Environment, and the Receptive-Expressive Emergent Language Scale (REEL). Results on the FACES III revealed that families were not rigid in adaptability; 61% were chaotic, and 33% were balanced. On the cohesion scale, 25% were disengaged, 30% were enmeshed, and 45% were balanced. On the FCOPES, and it's subscales, 36-40% of the respondents scored below the established norms. Social support was strongly correlated with Cohesion and Adaptability (r = .47, .67), HOME scores correlated with Self-Esteem (r = .47) and FCOPES Reframe scale (r = .45), and REEL scores correlated with Social Support (r = .47, .52). Path-analysis revealed two paths: help-seeking behaviors of the mother and the child-mother interactions.

  6. A Novel Mean-Value Model of the Cardiovascular System Including a Left Ventricular Assist Device.

    Science.gov (United States)

    Ochsner, Gregor; Amacher, Raffael; Schmid Daners, Marianne

    2017-06-01

    Time-varying elastance models (TVEMs) are often used for simulation studies of the cardiovascular system with a left ventricular assist device (LVAD). Because these models are computationally expensive, they cannot be used for long-term simulation studies. In addition, their equilibria are periodic solutions, which prevent the extraction of a linear time-invariant model that could be used e.g. for the design of a physiological controller. In the current paper, we present a new type of model to overcome these problems: the mean-value model (MVM). The MVM captures the behavior of the cardiovascular system by representative mean values that do not change within the cardiac cycle. For this purpose, each time-varying element is manually converted to its mean-value counterpart. We compare the derived MVM to a similar TVEM in two simulation experiments. In both cases, the MVM is able to fully capture the inter-cycle dynamics of the TVEM. We hope that the new MVM will become a useful tool for researchers working on physiological control algorithms. This paper provides a plant model that enables for the first time the use of tools from classical control theory in the field of physiological LVAD control.

  7. Experimental Assessment of the Hydraulics of a Miniature Axial-Flow Left Ventricular Assist Device

    Science.gov (United States)

    Smith, P. Alex; Cohn, William; Metcalfe, Ralph

    2017-11-01

    A minimally invasive partial-support left ventricular assist device (LVAD) has been proposed with a flow path from the left atrium to the arterial system to reduce left ventricular stroke work. In LVAD design, peak and average efficiency must be balanced over the operating range to reduce blood trauma. Axial flow pumps have many geometric parameters. Until recently, testing all these parameters was impractical, but modern 3D printing technology enables multi-parameter studies. Following theoretical design, experimental hydraulic evaluation in steady state conditions examines pressure, flow, pressure-flow gradient, efficiency, torque, and axial force as output parameters. Preliminary results suggest that impeller blades and stator vanes with higher inlet angles than recommended by mean line theory (MLT) produce flatter gradients and broader efficiency curves, increasing compatibility with heart physiology. These blades also produce less axial force, which reduces bearing load. However, they require slightly higher torque, which is more demanding of the motor. MLT is a low order, empirical model developed on large pumps. It does not account for the significant viscous losses in small pumps like LVADs. This emphasizes the importance of experimental testing for hydraulic design. Roderick D MacDonald Research Fund.

  8. Control of a haptic gear shifting assistance device utilizing a magnetorheological clutch

    International Nuclear Information System (INIS)

    Han, Young-Min; Choi, Seung-Bok

    2014-01-01

    This paper proposes a haptic clutch driven gear shifting assistance device that can help when the driver shifts the gear of a transmission system. In order to achieve this goal, a magnetorheological (MR) fluid-based clutch is devised to be capable of the rotary motion of an accelerator pedal to which the MR clutch is integrated. The proposed MR clutch is then manufactured, and its transmission torque is experimentally evaluated according to the magnetic field intensity. The manufactured MR clutch is integrated with the accelerator pedal to transmit a haptic cue signal to the driver. The impending control issue is to cue the driver to shift the gear via the haptic force. Therefore, a gear-shifting decision algorithm is constructed by considering the vehicle engine speed concerned with engine combustion dynamics, vehicle dynamics and driving resistance. Then, the algorithm is integrated with a compensation strategy for attaining the desired haptic force. In this work, the compensator is also developed and implemented through the discrete version of the inverse hysteretic model. The control performances, such as the haptic force tracking responses and fuel consumption, are experimentally evaluated. (paper)

  9. Control of a haptic gear shifting assistance device utilizing a magnetorheological clutch

    Science.gov (United States)

    Han, Young-Min; Choi, Seung-Bok

    2014-10-01

    This paper proposes a haptic clutch driven gear shifting assistance device that can help when the driver shifts the gear of a transmission system. In order to achieve this goal, a magnetorheological (MR) fluid-based clutch is devised to be capable of the rotary motion of an accelerator pedal to which the MR clutch is integrated. The proposed MR clutch is then manufactured, and its transmission torque is experimentally evaluated according to the magnetic field intensity. The manufactured MR clutch is integrated with the accelerator pedal to transmit a haptic cue signal to the driver. The impending control issue is to cue the driver to shift the gear via the haptic force. Therefore, a gear-shifting decision algorithm is constructed by considering the vehicle engine speed concerned with engine combustion dynamics, vehicle dynamics and driving resistance. Then, the algorithm is integrated with a compensation strategy for attaining the desired haptic force. In this work, the compensator is also developed and implemented through the discrete version of the inverse hysteretic model. The control performances, such as the haptic force tracking responses and fuel consumption, are experimentally evaluated.

  10. Effects of Thoratec pulsatile ventricular assist device timing on the abdominal aortic wave intensity pattern.

    Science.gov (United States)

    Jahren, Silje Ekroll; Amacher, Raffael; Weber, Alberto; Most, Henriette; Flammer, Shannon Axiak; Traupe, Tobias; Stoller, Michael; de Marchi, Stefano; Vandenberghe, Stijn

    2014-10-15

    Arterial waves are seen as possible independent mediators of cardiovascular risks, and the wave intensity analysis (WIA) has therefore been proposed as a method for patient selection for ventricular assist device (VAD) implantation. Interpreting measured wave intensity (WI) is challenging, and complexity is increased by the implantation of a VAD. The waves generated by the VAD interact with the waves generated by the native heart, and this interaction varies with changing VAD settings. Eight sheep were implanted with a pulsatile VAD (PVAD) through ventriculoaortic cannulation. The start of PVAD ejection was synchronized to the native R wave and delayed between 0 and 90% of the cardiac cycle in 10% steps or phase shifts (PS). Pressure and velocity signals were registered, with the use of a combined Doppler and pressure wire positioned in the abdominal aorta, and used to calculate the WI. Depending on the PS, different wave interference phenomena occurred. Maximum unloading of the left ventricle (LV) coincided with constructive interference and maximum blood flow pulsatility, and maximum loading of the LV coincided with destructive interference and minimum blood flow pulsatility. We believe that noninvasive WIA could potentially be used clinically to assess the mechanical load of the LV and to monitor the peripheral hemodynamics such as blood flow pulsatility and risk of intestinal bleeding. Copyright © 2014 the American Physiological Society.

  11. Monitoring of Diaphragm Position in Pulsatile Pnumatic Ventricular Assisted Device by Ultrasound Sensor

    Science.gov (United States)

    Kamimura, Tadayuki; Homma, Akihiko; Tsukiya, Tomonori; Kakuta, Yukihide; Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki; Kitamura, Soichiro

    A new method using ultrasound sensors to detect the diaphragm position of a ventricular assist device (VAD) was proposed. Two small ultrasound sensors of 2.4mm diameter were attached to the outside surface of blood chamber of a pneumatic VAD. The receiving crystal received the ultrasound from the transmitting crystal reflected by the diaphragm. The diaphragm position was calculated by using geometric relation among two sensors and ultrasound propagation time. Validity of this method was evaluated in a mock circulation test under various driving conditions of VAD by comparing the ultrasound signals with driving pressure waveforms. The ultrasound signals could detect full-fill (FF) and full-eject (FE) status shortly before the spikes appeared on pressure waves, which are currently available to detect FE and FF but accompanies excessive extension of the diaphragm. This method would be helpful to avoid overloading of diaphragm. Linear correlation was observed between the output from VAD and blood volume calculated from the change of diaphragm position multiplied by the heart rate. This monitoring method of diaphragm of a VAD was proven to have advantages over the current method toward better control of a pneumatic VAD.

  12. Left ventricular assist device implantation in patients after left ventricular reconstruction.

    Science.gov (United States)

    Palmen, Meindert; Braun, Jerry; Beeres, Saskia L M A; Klautz, Robert J M

    2016-12-01

    Left ventricular assist device (LVAD) implantation can be challenging in patients with a prior surgical ventricular restoration (SVR). In this case series of heart failure patients with a history of SVR, we describe the surgical technique and outcome of a customized approach for inflow cannula orientation. Seven patients with a history of SVR with end-stage chronic heart failure were accepted for long-term LVAD support. In all patients, the Dacron patch was removed through left ventriculotomy and a Hegar 22 dilator was inserted at the estimated optimal position of the LVAD inflow cannula. The left ventricle was reconstructed around the dilator from the left ventricular (LV) apex to the base. Finally, the LVAD sewing ring was sutured onto the remaining apical defect and a HeartWare® LVAD was implanted. LVAD implantation was successful in all 7 patients. Transoesophageal echocardiography ensured an adequate LVAD position and inflow and outflow cannula Doppler flow recordings. The mean intensive care unit stay was 5.8 ± 2.6 days, and the hospital stay after surgery was 32 ± 16 days. All patients follow regular visits (follow-up 20 ± 16 months) at the outpatient clinic without any remarkable event. Using the technique described, LVAD implantation in patients after SVR is feasible and safe. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  13. Cardiac passive-aggressive behavior? The right ventricle in patients with a left ventricular assist device.

    Science.gov (United States)

    Kimmaliardjuk, Donna May; Ruel, Marc

    2017-04-01

    Right ventricular failure (RVF) affects up to 50% of patients post-left ventricular assist device (LVAD) implantation, and carries significant morbidity and mortality. There is no widely-used long-term mechanical support option for the right ventricle, thus early identification, prevention and medical treatment of RVF is of the upmost importance. Areas covered: A PubMed search was first completed searching 'Right ventricular failure post-LVAD' which yielded 152 results, and a subsequent search was performed under 'RV mechanical support' which yielded 374 results, and was filtered to 'humans' and literature written in English, generating 219 results. We focused this research on pre-operative risk factors identified in the literature for developing RVF-post LVAD implantation, and the medical and surgical treatment options for RVF, including mechanical treatment options. Expert commentary: There is little consensus on pre-operative risk factors that reliably predict RVF post-LVAD implantation. Large prospective randomized trials would help clarify indications for specific medical and surgical therapy. We gather this knowledge in the present article and describe the main RVF remediation modalities. Surgeons and anesthesiologists should help prevent and have a low threshold for initiating supportive treatment for RVF, which may include increasingly invasive therapies up to long-term mechanical RV support.

  14. Preliminary evaluation of nickel/cadmium cells for a totally implantable ventricular assist device

    Science.gov (United States)

    Shu, Zhi Xin; Aiken, Peter A.; MacLean, Gregory K.; Adams, William A.

    A preliminary evaluation on the performance characteristics of three types of Ni/Cd cells was carried out in order to determine their potential usefulness in the internal (implantable) battery for the electrohydraulic ventricular assist device (EVAD) being developed at the University of Ottawa Heart Institute and University of Utah. The parameters studied at 37 °C were memory effect, discharge rate capability, self-discharge, surface temperature increase during charge and discharge and cycle life under the average power drain of the EVAD. Standard cells (designated 'S'), which were designed for room temperature use, suffered from a memory effect and had a low cycle life (114 cycles) and were, therefore, rejected for use in the EVAD. Two other types of cells (designated 'P' and 'H'), which were designed for higher temperature use, were comparable in their overall performance showing little or no memory effect and good cycle life (514 and 358 cycles, respectively). These latter two types of cells could be potential candidates for use in EVAD's internal battery.

  15. The Importance of the Management of Infectious Complications for Patients with Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Michinari Hieda

    2015-08-01

    Full Text Available A left ventricular assist device (LVAD therapy is the viable option for patients with advanced heart failure as a bridge to transplantation, bridge to recovery, or destination therapy. Although application of LVAD support has become a standard option, serious complications or adverse events related with LVAD remain a concern. LVAD-related infection including driveline infection (DLI and bloodstream infection (BSI is one of the serious clinical matters for LVAD patients, and especially BSI leads to the high incidence of mortality. The LVAD-related infections negatively impact patient’s quality of life. Therefore, control of infection is one of the primary goals of management in LVAD patients. Several efforts including early and appropriate intervention including antibiotics and wound care may contribute to avert the progress into BSI from localized DLI. Particularly, there are clinical secrets in how to use antibiotics and how to treat wound care in LVAD patients. The rational way of thinking for wound care will be introduced in this review.

  16. Effects of Sevoflurane and Propofol on Organ Blood Flow in Left Ventricular Assist Devices in Pigs

    Science.gov (United States)

    Morillas-Sendín, Paloma; Delgado-Baeza, Emilio; Delgado-Martos, María Jesús; Barranco, Mónica; del Cañizo, Juan Francisco; Ruíz, Manuel

    2015-01-01

    The aim of this study was to assess the effect of sevoflurane and propofol on organ blood flow in a porcine model with a left ventricular assist device (LVAD). Ten healthy minipigs were divided into 2 groups (5 per group) according to the anesthetic received (sevoflurane or propofol). A Biomedicus centrifugal pump was implanted. Organ blood flow (measured using colored microspheres), markers of tissue injury, and hemodynamic parameters were assessed at baseline (pump off) and after 30 minutes of partial support. Blood flow was significantly higher in the brain (both frontal lobes), heart (both ventricles), and liver after 30 minutes in the sevoflurane group, although no significant differences were recorded for the lung, kidney, or ileum. Serum levels of alanine aminotransferase and total bilirubin were significantly higher after 30 minutes in the propofol group, although no significant differences were detected between the groups for other parameters of liver function, kidney function, or lactic acid levels. The hemodynamic parameters were similar in both groups. We demonstrated that, compared with propofol, sevoflurane increases blood flow in the brain, liver, and heart after implantation of an LVAD under conditions of partial support. PMID:26583144

  17. Pulmonary Artery Pulsatility Index Is Associated With Right Ventricular Failure After Left Ventricular Assist Device Surgery.

    Science.gov (United States)

    Morine, Kevin J; Kiernan, Michael S; Pham, Duc Thinh; Paruchuri, Vikram; Denofrio, David; Kapur, Navin K

    2016-02-01

    Right ventricular failure (RVF) is a major cause of morbidity and mortality after CF-LVAD implantation. We explored the association of pulmonary artery compliance (PAC), pulmonary artery elastance (PAE), and pulmonary artery pulsatility index (PAPi) in addition to established parameters as preoperative determinants of postoperative RVF after CF-LVAD surgery. We retrospectively reviewed 132 consecutive CF-LVAD implantations at Tufts Medical Center from 2008 to 2013. Clinical, hemodynamic, and echocardiographic data were studied. RVF was defined as the unplanned need for a right ventricular assist device or inotrope dependence for ≥14 days. Univariate analysis was performed. RVF occurred in 32 of 132 patients (24%). PAC and PAE were not changed, whereas the PAPi was lower among patients with versus without postoperative RVF (1.32 ± 0.46 vs 2.77 ± 1.16; P < .001). RA pressure, RA to pulmonary capillary wedge pressure ratio (RA:PCWP), and RV stroke work index (RVSWI) were also associated with RVF. Using receiver operating characteristic curve-derived cut-points, PAPi < 1.85 provided 94% sensitivity and 81% specificity (C-statistic = 0.942) for identifying RVF and exceeded the predictive value of RA:PCWP, RVSWI, or RA pressure alone. PAPi is a simple hemodynamic variable that may help to identify patients at high risk of developing RVF after LVAD implantation. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Ventricular Assist Device in Single-Ventricle Heart Disease and a Superior Cavopulmonary Anastomosis.

    Science.gov (United States)

    Niebler, Robert A; Shah, Tejas K; Mitchell, Michael E; Woods, Ronald K; Zangwill, Steven D; Tweddell, James S; Berger, Stuart; Ghanayem, Nancy S

    2016-02-01

    Our objective is to describe the use of a ventricular assist device (VAD) in single-ventricle patients with circulatory failure following superior cavopulmonary anastomosis (SCPA). We performed a retrospective chart review of all single-ventricle patients supported with a VAD following SCPA. Implantation techniques, physiologic parameters while supported, medical and surgical interventions postimplant, and outcomes were reviewed. Four patients were supported with an EXCOR Pediatric (Berlin Heart Inc., The Woodlands, TX, USA) following SCPA for a median duration of 10.5 days (range 9-312 days). Selective excision of trabeculae and chords facilitated apical cannulation in all patients without inflow obstruction. There were two pump exchanges in the one patient supported for 312 days. Two patients were evaluated by cardiac catheterization while supported. Three of four patients were successfully bridged to transplantation. One patient died while supported. All patients had significant bleeding at the time of transplantation, and one required posttransplant extracorporeal membrane oxygenation with subsequent full recovery. VAD support can provide a successful bridge to transplantation in patients with single-ventricle circulation following SCPA. A thorough understanding of the challenges encountered during this support is necessary for successful outcomes. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  19. The Role of Computed Tomography in Predicting Left Ventricular Assist Device Infectious Complications

    Directory of Open Access Journals (Sweden)

    Carrie K Gomez

    2016-01-01

    Full Text Available Objective: The purpose of this study is to identify early computed tomography findings around the driveline which would predict mediastinal or left ventricular assist device (LVAD pocket abscess formation. Materials and Methods: A retrospective analysis was performed on 128 LVAD recipients between January 2007 and December 2011. Infectious complications were subdivided into those affecting the driveline and those resulting in abscess formation either around the LVAD pump or mediastinum. The size and location of infiltrative changes surrounding the driveline were used to predict infection propagation resulting in abscess. Results: Of the 128 patients, 49 (38.3% patients developed driveline infections and 24 (18.8% patients developed abscess. 87.5% patients who developed abscess had a preceding driveline infection. The mean time from driveline infection to the development of pump pocket abscess was approximately 7 months. In addition, patients with abscess in the pump pocket or mediastinum had preceding infiltrative changes surrounding the driveline ≥14 mm (P = 0.0001. A preperitoneal location and size of infiltrative changes ≥14 mm were correlated with a higher likelihood of abscess formation (P = 0.0002. Conclusion: Our study demonstrates the predictive value of infection/infiltrative changes around the driveline, which increases the risk for abscess formation in the LVAD pump pocket and/or in the mediastinum.

  20. iOS--Worthy of the Hype as Assistive Technology for Visual Impairments? A Phenomenological Study of iOS Device Use by Individuals with Visual Impairments

    Science.gov (United States)

    Scott, Shari

    2013-01-01

    This qualitative study sought to explore the shared essence of the lived experiences of early adopters of iOS devices as assistive technology by persons with visual impairments. The capstone question addressed the idea of whether any one device could fully meet the assistive technology needs of this population. Purposeful sampling methods were…

  1. 78. Asistencia biventricular de larga duración mediante dispositivo heartware hvad miniaturizado

    Directory of Open Access Journals (Sweden)

    M.T. González López

    2012-04-01

    Conclusiones: Existe una limitada experiencia a nivel mundial con el empleo de asistencia de flujo continuo en el corazón derecho. Sin embargo, este tipo de dispositivo permite una técnica relativamente sencilla de implantación, junto con una mayor autonomía y calidad de vida del paciente que precisa soporte biventricular de larga duración como puente al trasplante.

  2. Surgical outcomes of 380 patients with double outlet right ventricle who underwent biventricular repair.

    Science.gov (United States)

    Li, Shoujun; Ma, Kai; Hu, Shengshou; Hua, Zhongdong; Yang, Keming; Yan, Jun; Chen, Qiuming

    2014-09-01

    The study objective was to report the outcomes of biventricular repair in patients with double outlet right ventricle. Patients with double outlet right ventricle who underwent biventricular repair at Fuwai Hospital from January 2005 to December 2012 were included. Patients were excluded if double outlet right ventricle was combined with atrioventricular septal defect, heterotaxy syndrome, atrioventricular discordance, or univentricular physiology. A total of 380 consecutive patients with a mean age of 1.9 ± 2.1 years (range, 1 month to 6 years) were included. Varied types of biventricular repair were customized individually. Follow-up was 90.4% complete, and the mean follow-up time was 3.4 ± 3.9 years. There were 17 (4.5%) early deaths and 7 (2.1%) late deaths. Preoperative pulmonary hypertension was the only risk factor for early mortality. Postoperative significant left ventricular outflow tract obstruction was present in 9 survivors. Patients with noncommitted ventricular septal defect had a longer crossclamp time, longer cardiopulmonary bypass time, and higher incidence of postdischarge left ventricular outflow tract obstruction. There were 4 reoperations, all of which were caused by subaortic left ventricular outflow tract obstruction. All of the pressure gradients were decreased to less than 20 mm Hg after the modified Konno procedure with an uneventful postoperative course. Optimal results of varied types of biventricular repair for double outlet right ventricle have been acquired. Although noncommitted ventricular septal defect is technically difficult, the outcomes of patients are favorable. Late-onset left ventricular outflow tract obstruction is the main reason for reoperation but can be successfully relieved by the modified Konno procedure. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  3. Sequential biventricular pacing improves regional contractility, longitudinal function and dyssynchrony in patients with heart failure and prolonged QRS

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    Ring Margareta

    2010-04-01

    Full Text Available Abstract Aims Biventricular pacing (BiP is an effective treatment in systolic heart failure (HF patients with prolonged QRS. However, approximately 35% of the patients receiving BiP are classified as non-responders. The aim of this study is to evaluate the acute effects of VV-optimization on systolic heart function. Methods Twenty-one HF patients aged 72 (46-88 years, QRS 154 (120-190 ms, were studied with echocardiography, Tissue Doppler Imaging (TDI and 3D-echo the first day after receiving a BiP device. TDI was performed; during simultaneous pacing (LV-lead pacing 4 ms before the RV-lead and during sequential pacing (LV 20 and 40 ms before RV and RV 20 and 40 ms before LV-lead pacing. Systolic heart function was studied by tissue tracking (TT for longitudinal function and systolic maximal velocity (SMV for regional contractility and signs of dyssynchrony assessed by time-delays standard deviation of aortic valve opening to SMV, AVO-SMV/SD and tissue synchronization imaging (TSI. Results The TT mean value preoperatively was 4,2 ± 1,5 and increased at simultaneous pacing to 5,0 ± 1,2 mm (p Conclusions VV-optimization in the acute phase improves systolic heart function more than simultaneous BiP pacing. Long-term effects should be evaluated in prospective randomized trials.

  4. Ventricular resynchronization through biventricular cardiac pacing for the treatment of refractory heart failure in dilated cardiomyopathy

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    Silas S. Galvão Fº

    2002-01-01

    Full Text Available OBJECTIVE: The biventricular pacing (BVP approach has good results in the treatment of congestive heart failure (CHF in patients (pts with disorders of intraventricular conduction. METHODS: We have applied BVP to 28 pts, with left ventricular pacing using minitoracotomy in 3 pts and the transvenous aproach via coronary sinus in 25 pts. The mean duration of the QRS complexes was 187 ms, in the presence of the left branch block in 22 pts, and right branch block + divisional hemiblock in 6 pts. All pts had been considerated candidates to cardiac transplantation, and were under optimized drug therapy. Sixteen pts were in Functional Class (NYHA IV, and 12 in class III. The ejection fraction varied from 22 to 46% (average = 34%. The pacing mode employed was biventricular triple-chamber in 22 pts, and bi-ventricular dual-chamber in 6 pts (one with ICD. RESULTS: The pts were followed up for a period that ranged from 10 days to 14 months (mean 5 months. All pts presented clinical improvement after implant, chaging the NYHA Functional Class at the end of follow-up to Class I (9pts, Class II (10 pts and Class III (6 pts. The initial mean ejection fraction have-raised to 37%. Two pts died suddenly. One patient died due to a pulmonary fungal infection. CONCLUSION: Ventricular resynchronization through BVP, improved significantly the Functional Class and, therefore, the quality of life. Assessments of myocardial function acutely performed do not reflect the clinical improvement observed.

  5. Performance and management of implantable lithium battery systems for left ventricular assist devices and total artificial hearts

    Science.gov (United States)

    Dodd, J.; Kishiyama, C.; Mukainakano, Hiroshi; Nagata, M.; Tsukamoto, H.

    A lithium ion cell designed for implantable medical devices was tested for its performance as a power source for left ventricular assist devices (LVAD) or total artificial hearts (TAH). These two cardiovascular devices require high power, and thus a high current (0.5-3 A) and high voltage (20-30 V). Since these are implantable medical devices, in addition to high power capability, the power source should have long cycle life and calendar life, as well as high safety. The QL0700I, a 700 mAh cell, was cycled at 0.5 C rate as well as at 1.5 C rate, and the cycle life capacity retention was evaluated after numerous cycles. A battery pack consisting of seven QL0700I cells in series, with a battery management system (BMS) connected, was tested for rate capability as well as safety protection.

  6. Biocompatible Evaluation Of Biomaterials Used In The New Polish Extracorporeal Pulsatile Heart Assist Device ReligaHeart EXT

    Directory of Open Access Journals (Sweden)

    Gonsior M.

    2015-09-01

    Full Text Available The innovative extracorporeal heart support device ReligaHeart (RH EXT has been developed, based on POLVAD ventricular assist device clinical experience, collected in more than 300 patient applications. The innovative surface engineering technologies are applied in ReligaHeart EXT device. The pump is manufactured of new generation, modified surface structure, biocompatible polyurethanes, and equipped with original tilting disc valves, Moll type. The valve ring is made of titanium alloy, TiN+Ti2N+αTi(N diffusive layer modified, produced with glow discharge at plasma potential, in order to obtain the lowest thrombogenicity. The valve disc is made of polyether ether ketone. The complex in vitro and in vivo biological evaluations were performed, confirming both biomaterials biocompatible properties and device biocompatibility, proved in 30 days animal heart support.

  7. Metabolic volume performs better than SUVmax in the detection of left ventricular assist device driveline infection

    Energy Technology Data Exchange (ETDEWEB)

    Avramovic, Nemanja; Weckesser, Matthias; Milankovic, Danka; Vrachimis, Alexis; Wenning, Christian [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Dell' Aquila, Angelo Maria; Sindermann, Juergen R. [University Hospital Muenster, Department of Cardiac Surgery, Muenster (Germany)

    2017-10-15

    A continuous-flow left ventricular assist device (LVAD) is a new and highly promising therapy in supporting end-stage heart failure patients, either bridging them to heart transplantation or as a destination therapy. Infection is one of the major complications associated with LVAD implants. {sup 18}F-FDG PET/CT has already been shown to be useful in the detection of LVAD infection. The goal of this study was to compare the diagnostic accuracy of different PET analysis techniques (visual grading versus SUVmax and metabolic volume). We retrospectively analyzed 48 patients with implanted LVAD who underwent an {sup 18}F-FDG PET/CT that were either suspected to have a driveline or device infection or inflammation of unknown origin. PET/CT was analyzed qualitatively (visual grading) and quantitatively (SUVmax and metabolic volume) and matched to the final clinical diagnosis concerning driveline infection. The final diagnosis (standard of reference) was made at the end of clinically recorded follow-up or transplantation and included microbiological cultures of the driveline exit site and/or surgical samples, and clinical signs of infection despite negative cultures as well as recurrence of symptoms. Sensitivity, specificity, positive and negative predictive value were 87.5%, 79%, 81% and 86% for visual score, 87.5%, 87.5%, 87.5% and 87.5% for SUVmax and 96%, 87.5%, 88.5%, 95.5% for metabolic volume, respectively. ROC analysis revealed an AUC of.929 for SUVmax and.969 for metabolic volume. Both SUVmax and metabolic volume had a high detection rate of patients with driveline infection (21/24 = 91.5% true positive vs. 23/26 = 88.5% true positive, respectively). However, metabolic volume detected more patients without any infection correctly (1/22 = 4.5% false negative vs. 3/24 = 12.5% false negative). {sup 18}F-FDG PET/CT is a valuable tool for the diagnosis of LVAD driveline infection with high diagnostic accuracy. Particularly the use of the metabolic volume yields very

  8. In Vitro Evaluation of Inflow Cannula Fixation Techniques in Left Ventricular Assist Device Surgery.

    Science.gov (United States)

    Hanke, Jasmin S; Krabatsch, Thomas; Rojas, Sebastian V; Deniz, Ezin; Ismail, Issam; Martens, Andreas; Shrestha, Malakh; Haverich, Axel; Netuka, Ivan; Schmitto, Jan D

    2017-03-01

    The therapy of terminal heart failure with left ventricular assist devices has become a standard in cardiac surgery. Yet the surgical implantation technique is not standardized and differs from center to center. Complications associated with left ventricular assist device (LVAD) inflow cannula placement are thrombosis, suction events, and flow disturbances. Within this in vitro study we aimed to investigate if the fixation technique of the sewing ring has an impact on the position of the inflow cannula. For this in vitro study the HeartMate III LVAD (Thoratec Corporation, Pleasanton, CA, USA) was used. In five sessions, two approaches were considered for coring of the ventricle for LVAD inflow cannula insertion: "sew-then-core" and "core-then-sew." In the "sew-then-core" technique, the sewing cuff is first affixed to the heart, usually with 8-16 interrupted pledgeted mattress sutures. Subsequently, a cylindrical knife is used to resect a cylindrical core of myocardium to permit cannula insertion. In the "core-then-sew" technique, the sequence is reversed such that the knife is used before the suture ring is affixed. When the "sew-then-core" technique is used, the mattress sutures may be placed with full-thickness bites that penetrate the endocardium (i.e., transmural stitching) or partial-thickness bites that do not penetrate the endocardium (i.e., epicardial stitching). When the "core-then-sew" technique is used, the suture is passed fully into the ventricular lumen and fed back through the cored hole, at which point the needle may be reinserted into the freshly cored myocardium such that it exits the epicardium (i.e., transmural stitching with back stitch) or not (i.e., transmural stitching without back stitch). These four different sewing ring fixation suturing techniques were tested by experienced surgeons to affix the sewing ring: transmural stitching, epicardial stitching, transmural stitching with back stitch, and transmural stitching without back stitch

  9. POSTCARDIOTOMY SHOCK - CLINICAL-EVALUATION OF THE BVS-5000 BIVENTRICULAR SUPPORT SYSTEM

    NARCIS (Netherlands)

    GUYTON, RA; SCHONBERGER, JPAM; EVERTS, PAM; JETT, GK; GRAY, LA; GIELCHINSKY, [No Value; RAESS, DH; VLAHAKES, GJ; WOOLLEY, [No Value; GANGAHAR, DM; SOLTANZADEH, H; PICCIONE, WJ; VAUGHN, CC; BOONSTRA, PW; BUCKLEY, MJ

    This prospective trial evaluated the safety and efficacy of a new pulsatile, temporary ventricular assist device, the BVS 5000. Patients were eligible for treatment if they were hemodynamically unstable despite maximal pharmacologic and intraaortic balloon pump therapy, were free of concomitant

  10. Is Diabetes Mellitus a Risk Factor for Poor Outcomes after Left Ventricular Assist Device Placement?

    Science.gov (United States)

    Mohamedali, Burhan; Yost, Gardner; Bhat, Geetha

    2017-04-01

    Diabetes mellitus is associated with adverse outcomes in patients with cardiovascular diseases, including heart failure. Left ventricular assist devices (LVADs) are increasingly used as life-saving therapy for advanced heart failure. The effects of pre-LVAD diabetes on long-term outcomes after LVAD implantation are not well understood. In this study, we retrospectively evaluated the effect of existing diabetes on post-LVAD outcomes. Data on 288 LVAD recipients from 2006 through 2013 were reviewed. Patients were stratified in accordance with their histories of diabetes. Baseline demographic, laboratory, hemodynamic, and echocardiographic information before LVAD placement were reviewed, together with the post-LVAD incidence of major adverse outcomes. Kaplan-Meier analysis and Cox regression analysis were performed. Our cohort comprised 122 patients with diabetes and 166 patients without. The mean glycosylated hemoglobin A 1c level in the diabetes group was 7.4% ± 1.6%. Diabetic patients at baseline had a more adverse medical profile than did nondiabetic patients. There were no differences in major outcomes between the 2 groups other than a higher incidence of hemolysis in the diabetes group: 12 (10%) vs 5 (3%); P =0.02. There was no difference in survival outcomes between the groups. Diabetic patients did not have worse survival or more adverse outcomes than did nondiabetic patients in this study, perhaps because of improved diabetes control, or improvement in biochemical derangements after normalization of cardiac output with LVAD therapy. A diagnosis of diabetes was an independent predictor of hemolysis. Further studies to evaluate the link between hemolysis and diabetes are indicated.

  11. Evaluation of right ventricular function using liver stiffness in patients with left ventricular assist device.

    Science.gov (United States)

    Kashiyama, Noriyuki; Toda, Koichi; Nakamura, Teruya; Miyagawa, Shigeru; Nishi, Hiroyuki; Yoshikawa, Yasushi; Fukushima, Satsuki; Saito, Shunsuke; Yoshioka, Daisuke; Sawa, Yoshiki

    2017-04-01

    Although right ventricular failure (RVF) is a major concern after left ventricular assist device (LVAD) implantation, methodologies to evaluate RV function remain limited. Liver stiffness (LS), which is closely related to right-sided filling pressure and may indicate RVF severity, could be non-invasively and repeatedly assessed using transient elastography. Here we investigated the suitability of LS as a parameter of RV function in pre- and post-LVAD periods. The study included 55 patients with LVAD implantation as a bridge to transplantation between 2011 and 2015 whose LS was assessed using transient elastography. Seventeen patients presented with RVF, defined as requiring inotropic support for ≥30 days, nitric oxygen inhalation for ≥5 days, and/or mechanical RV support following LVAD implantation. Survival of patients with RVF was significantly worse compared with that of patients without RVF. Multivariate logistic regression analysis identified preoperative LS, LV diastolic dimension, RV stroke work index, and dilated phase of hypertrophic cardiomyopathy aetiology as significant risk factors; the combination of these parameters could improve predictive power of post-LVAD RVF with areas under the curve of 0.89. Furthermore, LS was significantly decreased by LV unloading and significantly correlated with right-sided filling pressure. In addition to dilated hypertrophic cardiomyopathy aetiology, reduced RV stroke work index and small LV dimension, we demonstrated that non-invasively measured LS was a predictor of post-LVAD RVF and can be used as a parameter for the evaluation and optimization of RV function in the perioperative period.

  12. Pulsatile operation of a continuous-flow right ventricular assist device (RVAD) to improve vascular pulsatility.

    Science.gov (United States)

    Ng, Boon C; Kleinheyer, Matthias; Smith, Peter A; Timms, Daniel; Cohn, William E; Lim, Einly

    2018-01-01

    Despite the widespread acceptance of rotary blood pump (RBP) in clinical use over the past decades, the diminished flow pulsatility generated by a fixed speed RBP has been regarded as a potential factor that may lead to adverse events such as vasculature stiffening and hemorrhagic strokes. In this study, we investigate the feasibility of generating physiological pulse pressure in the pulmonary circulation by modulating the speed of a right ventricular assist device (RVAD) in a mock circulation loop. A rectangular pulse profile with predetermined pulse width has been implemented as the pump speed pattern with two different phase shifts (0% and 50%) with respect to the ventricular contraction. In addition, the performance of the speed modulation strategy has been assessed under different cardiovascular states, including variation in ventricular contractility and pulmonary arterial compliance. Our results indicated that the proposed pulse profile with optimised parameters (Apulse = 10000 rpm and ωmin = 3000 rpm) was able to generate pulmonary arterial pulse pressure within the physiological range (9-15 mmHg) while avoiding undesirable pump backflow under both co- and counter-pulsation modes. As compared to co-pulsation, stroke work was reduced by over 44% under counter-pulsation, suggesting that mechanical workload of the right ventricle can be efficiently mitigated through counter-pulsing the pump speed. Furthermore, our results showed that improved ventricular contractility could potentially lead to higher risk of ventricular suction and pump backflow, while stiffening of the pulmonary artery resulted in increased pulse pressure. In conclusion, the proposed speed modulation strategy produces pulsatile hemodynamics, which is more physiologic than continuous blood flow. The findings also provide valuable insight into the interaction between RVAD speed modulation and the pulmonary circulation under various cardiovascular states.

  13. The effect of ventricular assist devices on cerebral blood flow and blood pressure fractality

    International Nuclear Information System (INIS)

    Bellapart, Judith; Fraser, John F; Chan, Gregory S H; Tzeng, Yu-Chieh; Ainslie, Philip N; Dunster, Kimble R; Barnett, Adrian G; Boots, Rob

    2011-01-01

    Biological signals often exhibit self-similar or fractal scaling characteristics which may reflect intrinsic adaptability to their underlying physiological system. This study analysed fractal dynamics of cerebral blood flow in patients supported with ventricular assist devices (VAD) to ascertain if sustained modifications of blood pressure waveform affect cerebral blood flow fractality. Simultaneous recordings of arterial blood pressure and cerebral blood flow velocity using transcranial Doppler were obtained from five cardiogenic shock patients supported by VAD, five matched control patients and five healthy subjects. Computation of a fractal scaling exponent (α) at the low-frequency time scale by detrended fluctuation analysis showed that cerebral blood flow velocity exhibited 1/f fractal scaling in both patient groups (α = 0.95 ± 0.09 and 0.97 ± 0.12, respectively) as well as in the healthy subjects (α = 0.86 ± 0.07). In contrast, fluctuation in blood pressure was similar to non-fractal white noise in both patient groups (α = 0.53 ± 0.11 and 0.52 ± 0.09, respectively) but exhibited 1/f scaling in the healthy subjects (α = 0.87 ± 0.04, P < 0.05 compared with the patient groups). The preservation of fractality in cerebral blood flow of VAD patients suggests that normal cardiac pulsation and central perfusion pressure changes are not the integral sources of cerebral blood flow fractality and that intrinsic vascular properties such as cerebral autoregulation may be involved. However, there is a clear difference in the fractal scaling properties of arterial blood pressure between the cardiogenic shock patients and the healthy subjects

  14. Cognitive outcomes in pediatric heart transplant recipients bridged to transplantation with ventricular assist devices.

    Science.gov (United States)

    Stein, Mary Lynette; Bruno, Jennifer L; Konopacki, Kelly L; Kesler, Shelli; Reinhartz, Olaf; Rosenthal, David

    2013-02-01

    Ventricular assist devices (VADs) have been associated with high rates of neurologic injury in pediatric patients during the period of support, but the delayed consequences of this type of injury have not been described in the literature. In this study we assess cognitive outcomes with indices of general intellectual functioning, including working memory, processing speed, perceptual reasoning and verbal comprehension, for pediatric heart transplant recipients who required VAD support as a bridge to transplant (n = 9). We present an aggregate of these VAD patients combined with heart transplant recipients who did not require mechanical circulatory support (n = 11), and compare the performance of all transplant patients (n = 20) to typically developing, healthy comparators (n = 12). We also present a post hoc analysis of those transplant recipients with significant medical morbidity in the first year of life, referred to as the "high-risk" transplant group (n = 5), and compare them with the "low-risk" transplant group (n = 15) and the typically developing comparators (n = 12). The mean performance of the VAD patients was in the average range for each of the examined indices of cognitive functioning. A total of 11% of the VAD patients performed in the impaired range and 78% performed in the average range, with 11% in the superior range on measures of general intellectual functioning. The typically developing participants performed significantly better than the aggregated transplant recipients on all indices except verbal comprehension. Lower cognitive performance in the combined transplant group appears to be associated with medical morbidity in the first year of life. Despite significant neurologic risk factors, this cohort of pediatric patients who were bridged to transplant with VAD demonstrated resiliency in terms of cognitive outcomes. In this heterogeneous population, it is likely that multiple factors contributed to the cognitive outcomes. As VAD use becomes

  15. Acoustic puncture assist device versus loss of resistance technique for epidural space identification

    Directory of Open Access Journals (Sweden)

    Amit Kumar Mittal

    2016-01-01

    Full Text Available Background and Aims: The conventional techniques of epidural space (EDS identification based on loss of resistance (LOR have a higher chance of complications, patchy analgesia and epidural failure, which can be minimised by objective confirmation of space before catheter placement. Acoustic puncture assist device (APAD technique objectively confirms EDS, thus enhancing success, with lesser complications. This study was planned with the objective to evaluate the APAD technique and compare it to LOR technique for EDS identification and its correlation with ultrasound guided EDS depth. Methods: In this prospective study, the lumbar vertebral spaces were scanned by the ultrasound for measuring depth of the EDS and later correlated with procedural depth measured by either of the technique (APAD or LOR. The data were subjected to descriptive statistics; the concordance correlation coefficient and Bland-Altman analysis with 95% confidence limits. Results: Acoustic dip in pitch and descent in pressure tracing on EDS localisation was observed among the patients of APAD group. Analysis of concordance correlation between the ultrasonography (USG depth and APAD or LOR depth was significant (r ≥ 0.97 in both groups. Bland-Altman analysis revealed a mean difference of 0.171cm in group APAD and 0.154 cm in group LOR. The 95% limits of agreement for the difference between the two measurements were − 0.569 and 0.226 cm in APAD and − 0.530 to 0.222 cm in LOR group. Conclusion: We found APAD to be a precise tool for objective localisation of the EDS, co-relating well with the pre-procedural USG depth of EDS.

  16. Comparison of fasciotomy wound closures using traditional dressing changes and the vacuum-assisted closure device.

    Science.gov (United States)

    Zannis, John; Angobaldo, Jeff; Marks, Malcolm; DeFranzo, Anthony; David, Lisa; Molnar, Joseph; Argenta, Louis

    2009-04-01

    Fasciotomy wounds can be a major contributor to length of stay for patients as well as a difficult reconstructive challenge. Once the compartment pressure has been relieved and stabilized, the wound should be closed as quickly and early as possible to avoid later complications. Skin grafting can lead to morbidity and scarring at both the donor and fasciotomy site. Primary closure results in a more functional and esthetic outcome with less morbidity for the patient, but can often be difficult to achieve secondary to edema, skin retraction, and skin edge necrosis. Our objective was to examine fasciotomy wound outcomes, including time to definitive closure, comparing traditional wet-to-dry dressings, and the vacuum-assisted closure (VAC) device. This retrospective chart review included a consecutive series of patients over a 10-year period. This series included 458 patients who underwent 804 fasciotomies. Of these fasciotomy wounds, 438 received exclusively VAC. dressings, 270 received only normal saline wet-to-dry dressings, and 96 were treated with a combination of both. Of the sample, 408 patients were treated with exclusively VAC therapy or wet-to-dry dressings and 50 patients were treated with a combination of both. In comparing all wounds, there was a statistically significant higher rate of primary closure using the VAC versus traditional wet-to-dry dressings (P lower extremities and P extremities). The time to primary closure of wounds was shorter in the VAC. group in comparison with the non-VAC group. This study has shown that the use of the VAC for fasciotomy wound closure results in a higher rate of primary closure versus traditional wet-to-dry dressings. In addition, the time to primary closure of wounds or time to skin grafting is shorter when the VAC was employed. The VAC used in the described settings decreases hospitalization time, allows for earlier rehabilitation, and ultimately leads to increased patient satisfaction.

  17. Stereotypes Associated With Age-related Conditions and Assistive Device Use in Canadian Media.

    Science.gov (United States)

    Fraser, Sarah Anne; Kenyon, Virginia; Lagacé, Martine; Wittich, Walter; Southall, Kenneth Edmund

    2016-12-01

    Newspapers are an important source of information. The discourses within the media can influence public attitudes and support or discourage stereotypical portrayals of older individuals. This study critically examined discourses within a Canadian newspaper in terms of stereotypical depictions of age-related health conditions and assistive technology devices (ATDs). Four years (2009-2013) of Globe and Mail articles were searched for terms relevant to the research question. A total of 65 articles were retained, and a critical discourse analysis (CDA) of the texts was conducted. The articles were coded for stereotypes associated with age-related health conditions and ATDs, consequences of the stereotyping, and context (overall setting or background) of the discourse. The primary code list included 4 contexts, 13 stereotypes, and 9 consequences of stereotyping. CDA revealed discourses relating to (a) maintaining autonomy in a stereotypical world, (b) ATDs as obstacles in employment, (c) barriers to help seeking for age-related conditions, and (d) people in power setting the stage for discrimination. Our findings indicate that discourses in the Canadian media include stereotypes associated with age-related health conditions. Further, depictions of health conditions and ATDs may exacerbate existing stereotypes about older individuals, limit the options available to them, lead to a reduction in help seeking, and lower ATD use. Education about the realities of age-related health changes and ATDs is needed in order to diminish stereotypes and encourage ATD uptake and use. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Vacuum-assisted closure device for the management of infected postpneumonectomy chest cavities.

    Science.gov (United States)

    Perentes, Jean Yannis; Abdelnour-Berchtold, Etienne; Blatter, Jeannine; Lovis, Alban; Ris, Hans-Beat; Krueger, Thorsten; Gonzalez, Michel

    2015-03-01

    Infected postpneumonectomy chest cavities may be related to chronic postpneumonectomy empyema or arise in rare situations of necrotizing pneumonia with complete lung destruction where pneumonectomy and pleural debridement are required. We evaluated the safety and efficacy of an intrathoracic vacuum-assisted closure device (VAC) for the treatment of infected postpneumonectomy chest cavities. A retrospective single institution review of all patients with infected postpneumonectomy chest cavities treated by VAC between 2005 and 2013. Patients underwent surgical debridement of the thoracic cavity, muscle flap closure of the bronchial stump when a fistula was present, and repeated intrathoracic VAC dressings until granulation tissue covered the entire chest cavity. After this, the cavity was obliterated by a Clagett procedure and closed. Twenty-one patients (14 men and 7 women) underwent VAC treatment of their infected postpneumonectomy chest cavity. Twelve patients presented with a chronic postpneumonectomy empyema (10 of them with a bronchopleural fistula) and 9 patients with an empyema occurring in the context of necrotizing pneumonia treated by pneumonectomy. In-hospital mortality was 23%. The median duration of VAC therapy was 23 days (range, 4-61 days) and the median number of VAC changes per patient was 6 (range, 2-14 days). Infection control and successful chest cavity closure was achieved in all surviving patients. One adverse VAC treatment-related event was identified (5%). The intrathoracic VAC application is a safe and efficient treatment of infected postpneumonectomy chest cavities and allows the preservation of chest wall integrity. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  19. Development of a compact wearable pneumatic drive unit for a ventricular assist device.

    Science.gov (United States)

    Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Akagawa, Eiki; Lee, Hwansung; Nishinaka, Tomohiro; Takewa, Yoshiaki; Mizuno, Toshihide; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Shimosaki, Isao; Hamada, Shigeru; Mukaibayashi, Hiroshi; Iwaoka, Wataru

    2008-01-01

    The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.

  20. Granulomatous myocarditis in severe heart failure patients undergoing implantation of a left ventricular assist device.

    Science.gov (United States)

    Segura, Ana Maria; Radovancevic, Rajko; Demirozu, Zumrut T; Frazier, O H; Buja, L Maximilian

    2014-01-01

    Granulomatous myocarditis may develop into cardiomyopathy and severe congestive heart failure that requires implantation of a left ventricular assist device (LVAD). Left ventricular (LV) core samples were collected from 177 patients with severe heart failure at the time of LVAD implantation, and samples were histologically examined and graded for severity of hypertrophy and fibrosis. Granulomatous myocarditis incidentally seen in a subset of samples was characterized by staining and culturing for mycobacteria and fungi. Various clinical parameters in these patients were analyzed. Of the 177 LV core samples examined, 6 (3.4%) showed nonnecrotizing granulomatous inflammation in the myocardial wall. Stains and cultures for mycobacteria and fungi were negative. All six patients [three women, three men; five African American, one Asian; mean age, 52±9 years (range, 41-61 years)] had arrhythmias and required an automatic implantable cardioverter defibrillator. Before LVAD implantation, the patients' mean cardiac index was 1.8±0.4 l/min/m(2); cardiac output, 2.9±0.6 l/min; and ejection fraction, 20±2%. One year after LVAD implantation, one patient had undergone heart transplantation. At 2 years, a second patient was transplanted, and one died. At 3 years, a third patient was transplanted and died postoperatively; two patients remained on support. No clinical evidence indicated involvement of other organs or recurrence in the transplanted patients. The incidental diagnosis of granulomatous myocarditis in our patients indicates that histological study of LV core samples in patients who undergo LVAD implantation may contribute to the diagnosis and be a consideration in the management of the underlying cause of heart failure. © 2013.

  1. Left ventricular assist device effects on metabolic substrates in the failing heart.

    Directory of Open Access Journals (Sweden)

    Lindsay B Weitzel

    Full Text Available Heart failure patients have inadequate nutritional intake and alterations in metabolism contributing to an overall energy depleted state. Left ventricular assist device (LVAD support is a common and successful intervention in patients with end-stage heart failure. LVAD support leads to alterations in cardiac output, functional status, neurohormonal activity and transcriptional profiles but the effects of LVADs on myocardial metabolism are unknown. This study set out to measure cardiac metabolites in non-failing hearts, failing hearts, and hearts post-LVAD support.The study population consisted of 8 non-ischemic failing (at LVAD implant and 8 post-LVAD hearts, plus 8 non-failing hearts obtained from the tissue bank at the University of Colorado. NMR spectroscopy was utilized to evaluate differences in myocardial energy substrates. Paired and non-paired t-tests were used to determine differences between the appropriate groups.Glucose and lactate values both decreased from non-failing to failing hearts and increased again significantly in the (paired post-LVAD hearts. Glutamine, alanine, and aromatic amino acids decreased from non-failing to failing hearts and did not change significantly post-LVAD. Total creatine and succinate decreased from non-failing to failing hearts and did not change significantly post-LVAD.Measured metabolites related to glucose metabolism are diminished in failing hearts, but recovered their values post-LVAD. This differed from the amino acid levels, which decreased in heart failure but did not recover following LVAD. Creatine and the citric acid cycle intermediate succinate followed a similar pattern as the amino acid levels.

  2. Uncovering the cathepsin system in heart failure patients submitted to Left Ventricular Assist Device (LVAD) implantation.

    Science.gov (United States)

    D'Amico, Andrea; Ragusa, Rosetta; Caruso, Raffaele; Prescimone, Tommaso; Nonini, Sandra; Cabiati, Manuela; Del Ry, Silvia; Trivella, Maria Giovanna; Giannessi, Daniela; Caselli, Chiara

    2014-12-12

    In end-stage heart failure (HF), the implantation of a left ventricular assist device (LVAD) is able to induce reverse remodeling. Cellular proteases, such as cathepsins, are involved in the progression of HF. The aim of this study was to evaluate the role of cathepsin system in HF patients supported by LVAD, in order to determine their involvement in cardiac remodeling. The expression of cysteine (CatB, CatK, CatL, CatS) and serine cathepsin (CatG), and relative inhibitors (Cystatin B, C and SerpinA3, respectively) was determined in cardiac biopsies of 22 patients submitted to LVAD (pre-LVAD) and compared with: 1) control stable chronic HF patients on medical therapy at the moment of heart transplantation without prior LVAD (HT, n = 7); 2) patients supported by LVAD at the moment of transplantation (post-LVAD, n = 6). The expression of cathepsins and their inhibitors was significantly higher in pre-LVAD compared to the HT group and LVAD induced a further increase in the cathepsin system. Significant positive correlations were observed between cardiac expression of cathepsins and their inhibitors as well as inflammatory cytokines. In the pre-LVAD group, a relationship of cathepsins with dilatative etiology and length of hospitalization was found. A parallel activation of cathepsins and their inhibitors was observed after LVAD support. The possible clinical importance of these modifications is confirmed by their relation with patients' outcome. A better discovery of these pathways could add more insights into the cardiac remodeling during HF.

  3. Five-week use of a monopivot centrifugal blood pump as a right ventricular assist device in severe dilated cardiomyopathy.

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    Inoue, Takamichi; Kitamura, Tadashi; Torii, Shinzo; Hanayama, Naoji; Oka, Norihiko; Itatani, Keiichi; Tomoyasu, Takahiro; Irisawa, Yusuke; Shibata, Miyuki; Hayashi, Hidenori; Ono, Minoru; Miyaji, Kagami

    2014-03-01

    Right heart failure is a critical complication in patients requiring mechanical ventricular support. However, it is often difficult to provide adequate right ventricular support in the acute phase. A 41-year-old woman diagnosed with dilated cardiomyopathy with severe right heart failure underwent implantation of a paracorporeal pulsatile left ventricular assist device (LVAD, Nipro Corporation, Tokyo, Japan) and a MERA monopivot centrifugal pump (Senko Medical Instrument Manufacturing Co., Ltd., Tokyo, Japan) as a right ventricular assist device (RVAD). The patient developed ischemic enteritis 3 weeks after surgery, necessitating fasting and reversal of anticoagulation therapy. A target international normalized ratio of 1.5 was selected, and aspirin administration was discontinued. Following recovery without thromboembolic events, the patient failed the RVAD discontinuation test. Five weeks after surgery, the monopivot centrifugal pump was exchanged for a pulsatile pump. No thrombus was evident on the centrifugal pump. The patient was undergoing cardiac rehabilitation at the time of this writing and awaiting heart transplantation.

  4. In vivo evaluation of the "TinyPump" as a pediatric left ventricular assist device.

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    Kitao, Takashi; Ando, Yusuke; Yoshikawa, Masaharu; Kobayashi, Mariko; Kimura, Taro; Ohsawa, Hideyuki; Machida, Shinya; Yokoyama, Naoyuki; Sakota, Daisuke; Konno, Tomohiro; Ishihara, Kazuhiko; Takatani, Setsuo

    2011-05-01

    Pediatric patients with end-stage heart failure require mechanical circulatory support (MCS) just as adults do. In order to meet the special requirements for neonates' and infants' MCS, pediatric circulatory support devices must be compact with low priming volume, easily controllable with low flow, less traumatic for blood cells and tissues, and biocompatible with minimum anticoagulation. We have designed and developed a miniature rotary centrifugal blood pump, "TinyPump," with a priming volume of 5 mL, which has already demonstrated its controllable performance for low flow and durability in vitro. To evaluate the feasibility of the TinyPump as a left ventricular assist device (LVAD) suitable for neonates and infants, we have examined the biocompatibility and hemodynamic performance of the TinyPump in a pediatric animal model using Shiba goats. The TinyPump is a miniaturized centrifugal pump weighing 150 g comprising a disposable pump head with a 30-mm diameter impeller having six straight-vanes and a reusable motor driver. The impeller in the pump head is supported by a hydrodynamic bearing at its center and is driven by radial magnetic force coupled to the motor driver. TinyPump implantations were performed in 22 Shiba goats (17 female and 5 male), with body weights ranging from 8.4 to 27.2 kg. Under gas anesthesia, via left lateral thoracotomy, a 22 Fr inflow cannula was inserted through the left ventricular apex, while a 6-mm outflow graft was anastomosed to the descending aorta, which were then connected to a TinyPump mounted on the animal's back. Postoperative hemodynamic monitoring included heart rate, arterial and central venous pressure, pump flow, and rotation speed. Target pump flow in all animals was maintained at 0.9 ± 0.1 L/min, which is approximately half the normal pulmonary artery flow measured in control animals. Blood samples were collected to evaluate peripheral organ functions, hemolysis, and thrombosis. Goats were divided into three groups

  5. The role of temporary biventricular pacing in the cardiac surgical patient with severely reduced left ventricular systolic function.

    Science.gov (United States)

    Evonich, Rudolph F; Stephens, John C; Merhi, William; Dukkipati, Srinivas; Tepe, Nicholas; Shannon, Francis; Altshuler, Jeffrey; Sakwa, Marc; Bassett, Joseph; Hanson, Eric; Boura, Judy; O'Neill, William W; Haines, David E

    2008-10-01

    The objective was to evaluate the effects of atrial synchronous biventricular pacing in postoperative patients with severe cardiomyopathy. Atrial synchronous biventricular pacing epicardial leads were placed during cardiac surgery in patients with an ejection fraction of 30% or less. Patients were randomized to usual care pacing, the mode determined by the surgeon (excluding atrial synchronous biventricular pacing) with a preference for no pacing or atrial pacing (atrial inhibited pacing); atrial synchronous right ventricular pacing; or atrial synchronous biventricular pacing. Pacing was continued until cessation of hemodynamic support. At 12 hours postoperatively, patients were randomly tested in each mode (atrial inhibited, atrial synchronous right ventricular, and atrial synchronous biventricular pacing), and thermodilution outputs were measured. Forty subjects were randomized. Groups were similar in age (66 +/- 11 years), gender (85% were male), ejection fraction (23% +/- 6%), QRS duration (111 +/- 30 ms), and surgical indication. There was no difference in stroke index or cardiac index at 12 hours, duration of inotropic or intra-aortic balloon pump support, intensive care unit, or hospital length of stay. On comparative crossover testing, stroke volume was similar with atrial inhibited pacing and atrial synchronous biventricular pacing (59.3 +/- 13.4 vs 57 +/- 12.1, respectively, P = not significant); however, atrial synchronous right ventricular pacing was inferior (56 +/- 12.9, P or= 5%), whereas 41% had a 5% or greater decrease in stroke volume. Pacing mode affects stroke volume in patients with severe cardiomyopathy. Atrial synchronous biventricular pacing was helpful in a minority, but in 41% it compromised stroke volume.

  6. S100A1 in human heart failure: lack of recovery following left ventricular assist device support.

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    Bennett, Mosi K; Sweet, Wendy E; Baicker-McKee, Sara; Looney, Elizabeth; Karohl, Kristen; Mountis, Maria; Tang, W H Wilson; Starling, Randall C; Moravec, Christine S

    2014-07-01

    We hypothesized that S100A1 is regulated during human hypertrophy and heart failure and that it may be implicated in remodeling after left ventricular assist device. S100A1 is decreased in animal and human heart failure, and restoration produces functional recovery in animal models and in failing human myocytes. With the potential for gene therapy, it is important to carefully explore human cardiac S100A1 regulation and its role in remodeling. We measured S100A1, the sarcoplasmic endoplasmic reticulum Ca(2+)ATPase, phospholamban, and ryanodine receptor proteins, as well as β-adrenergic receptor density in nonfailing, hypertrophied (left ventricular hypertrophy), failing, and failing left ventricular assist device-supported hearts. We determined functional consequences of protein alterations in isolated contracting muscles from the same hearts. S100A1, sarcoplasmic endoplasmic reticulum Ca(2+)ATPase and phospholamban were normal in left ventricular hypertrophy, but decreased in failing hearts, while ryanodine receptor was unchanged in either group. Baseline muscle contraction was not altered in left ventricular hypertrophy or failing hearts. β-Adrenergic receptor and inotropic response were decreased in failing hearts. In failing left ventricular assist device-supported hearts, S100A1 and sarcoplasmic endoplasmic reticulum Ca(2+)ATPase showed no recovery, while phospholamban, β-adrenergic receptor, and the inotropic response fully recovered. S100A1 and sarcoplasmic endoplasmic reticulum Ca(2+)ATPase, both key Ca(2+)-regulatory proteins, are decreased in human heart failure, and these changes are not reversed after left ventricular assist device. The clinical significance of these findings for cardiac recovery remains to be addressed. © 2014 American Heart Association, Inc.

  7. A case of a pseudo colonic mass causing gastrointestinal bleeding in a patient with a left ventricular assist device

    Science.gov (United States)

    Huntington, Justin T.; Plews, Robert L.; Mansfield, Sara A.; Drosdeck, Joseph M.; Evans, David C.

    2016-01-01

    There are many complications associated with the left ventricular assist devices (LVADs), including gastrointestinal bleeding (GIB). We present a case of a pseudo colonic mass visualized on colonoscopy during workup for GIB in an LVAD patient necessitating a right colectomy with final pathology negative for malignancy. A review of the literature in regards to the pathology, diagnosis, and treatment of this interesting condition is included. PMID:27722118

  8. Optimal Design of Permanent Magnet Bearings with Application to the HeartQuestTM Ventricular Assist Device

    Science.gov (United States)

    Chen, Chen; Paden, Brad; Antaki, James; Ludlow, Jed; Bearnson, Gill

    Closed-form design equations for magnetic bearings are desirable for design optimization of sophisticated electrical mechanical systems such as artificial hearts. We develop asymptotic approximations to force and stiffness characteristics of magnetic bearings formed from concentric permanent magnet rings having rectangular cross sections. The equations are well adapted to spreadsheets and facilitate an efficient numerical optimization process. The method was applied to the development of the HeartQuestTM VAD (ventricular assist device), which achieved remarkable compactness and stable operation.

  9. Design of a Code-Maker Translator Assistive Input Device with a Contest Fuzzy Recognition Algorithm for the Severely Disabled

    Directory of Open Access Journals (Sweden)

    Chung-Min Wu

    2015-01-01

    Full Text Available This study developed an assistive system for the severe physical disabilities, named “code-maker translator assistive input device” which utilizes a contest fuzzy recognition algorithm and Morse codes encoding to provide the keyboard and mouse functions for users to access a standard personal computer, smartphone, and tablet PC. This assistive input device has seven features that are small size, easy installing, modular design, simple maintenance, functionality, very flexible input interface selection, and scalability of system functions, when this device combined with the computer applications software or APP programs. The users with severe physical disabilities can use this device to operate the various functions of computer, smartphone, and tablet PCs, such as sending e-mail, Internet browsing, playing games, and controlling home appliances. A patient with a brain artery malformation participated in this study. The analysis result showed that the subject could make himself familiar with operating of the long/short tone of Morse code in one month. In the future, we hope this system can help more people in need.

  10. Prospective cohort study of a new vacuum delivery device to assist with complicated labour in low-resource settings.

    Science.gov (United States)

    Khan, Mishal; Hashmani, Farah Naz; Ahmed, Sajjad; Ahmed, Owais; Asim, Shabnam S; Wajahat, Yasmin; Sobani, Shoaib; Syed, Shershah; Qazi, Fahad

    2015-02-01

    Currently available vacuum devices used to assist women undergoing complicated labour are unsuitable for use in low-resource settings. The objective of this study was to evaluate the safety and feasibility of a new low-cost vacuum device, named Koohi Goth Vacuum Delivery System (KGVDS), designed for use in low-resource settings. A hospital-based, multicentre, prospective cohort study with no control group was conducted in Karachi, Pakistan. After training, KGVDS devices were made available for use by labour room staff at their discretion when instrumental delivery was indicated. Women to whom KGVDS was applied were followed from the start of labour until discharge. Feasibility was assessed in terms of successful expulsion of the foetal head following application of KGVDS and ease of use ratings. Safety was assessed by observing maternal and newborn post-delivery outcomes prior to discharge. Koohi Goth Vacuum Delivery System was applied to 137 women requiring instrumental delivery, of whom 111 (81%; 95% CI = 74-88%) successfully expelled the foetal head assisted by KGVDS and 103 (75%) stated that they would agree to use KGVDS again. There were no serious maternal or neonatal injuries or infections related to KGVDS use. The mean score for 'ease of use' given by doctors and midwives using the device was 8 of 10. Koohi Goth Vacuum Delivery System was feasible and safe to use for assisting complicated deliveries in low-resource hospitals in this initial evaluation. Our results indicate that this new device may have the potential to improve birth outcomes in settings where most mortality occurs and that further evaluations should be conducted. © 2014 John Wiley & Sons Ltd.

  11. Jarvik 2000 axial-flow ventricular assist device placement to a systemic morphologic right ventricle in congenitally corrected transposition of the great arteries.

    Science.gov (United States)

    Tanoue, Yoshihisa; Jinzai, Yuki; Tominaga, Ryuji

    2016-03-01

    Few descriptions of the implantation and management of an implantable ventricular assist device in patients with complex congenital heart disease exist in the literature. The Jarvik 2000 axial-flow ventricular assist device (Jarvik Heart, Inc., NYC, NY, USA) can be placed in either the left or the right ventricle. We present the case of a 60-year-old man with congenitally corrected transposition of the great arteries who underwent successful placement of a Jarvik 2000 axial-flow ventricular assist device in a systemic morphologic right ventricle.

  12. Gastrointestinal bleeding and subsequent risk of thromboembolic events during support with a left ventricular assist device.

    Science.gov (United States)

    Stulak, John M; Lee, Dustin; Haft, Jonathon W; Romano, Matthew A; Cowger, Jennifer A; Park, Soon J; Aaronson, Keith D; Pagani, Francis D

    2014-01-01

    Modern left ventricular assist devices (LVAD) require anti-coagulation (AC) with warfarin and anti-platelet therapy to prevent thromboembolic complications in patients. Gastrointestinal bleeding (GI) is a significant adverse event in these patients and treatment typically requires reduction or elimination of AC or anti-platelet therapy. It is not known whether alterations in AC to treat GI bleeding influence subsequent risk of thromboembolic (TE) events during LVAD support. Between July 2003 and September 2011, 389 patients (308 male) underwent implantation of a continuous-flow LVAD at the University of Michigan Health System and the Mayo Clinic. Median age at implant was 60 years (range 18 to 79 years). Outcomes were analyzed for the association of GI bleeding events and subsequent TE events, defined as stroke, transient ischemic attack, hemolysis or suspected or confirmed pump thrombosis. Median survival was 10 months (maximum 7.2 years, total 439 patient-years). TE events occurring within the first 30 days were not counted. Overall survival and freedom from an outcome event were assessed using the Kaplan-Meier method. Associations between GI bleeding and subsequent TE events and survival impact were analyzed as time-dependent covariates. One hundred ninety-nine GI bleeding episodes occurred in 116 of 389 patients (30%) for an event rate of 0.45 GI bleed/patient-year of support. One hundred thirty-eight TE events occurred in 97 of 389 patients (25%) for an event rate of 0.31 TE event/patient-year of support. Median time from LVAD implant to first GI bleed was 5 months (range 1 to 116 months) and to first TE event was 6 months (range 1 to 29 months). For patients who had a TE event after GI bleed, the median interval was 5 months (range 0.5 to 25 months). TE events were 7.4-fold more likely in patients who had a prior GI bleed (range 4.9- to 11.1-fold) (p cause of this relationship is unknown, it suggests that a reduction in anti-coagulation and anti

  13. Fluid force predictions and experimental measurements for a magnetically levitated pediatric ventricular assist device.

    Science.gov (United States)

    Throckmorton, Amy L; Untaroiu, Alexandrina; Lim, D Scott; Wood, Houston G; Allaire, Paul E

    2007-05-01

    The latest generation of artificial blood pumps incorporates the use of magnetic bearings to levitate the rotating component of the pump, the impeller. A magnetic suspension prevents the rotating impeller from contacting the internal surfaces of the pump and reduces regions of stagnant and high shear flow that surround fluid or mechanical bearings. Applying this third-generation technology, the Virginia Artificial Heart Institute has developed a ventricular assist device (VAD) to support infants and children. In consideration of the suspension design, the axial and radial fluid forces exerted on the rotor of the pediatric VAD were estimated using computational fluid dynamics (CFD) such that fluid perturbations would be counterbalanced. In addition, a prototype was built for experimental measurements of the axial fluid forces and estimations of the radial fluid forces during operation using a blood analog mixture. The axial fluid forces for a centered impeller position were found to range from 0.5 +/- 0.01 to 1 +/- 0.02 N in magnitude for 0.5 +/- 0.095 to 3.5 +/- 0.164 Lpm over rotational speeds of 6110 +/- 0.39 to 8030 +/- 0.57% rpm. The CFD predictions for the axial forces deviated from the experimental data by approximately 8.5% with a maximum difference of 18% at higher flow rates. Similarly for the off-centered impeller conditions, the maximum radial fluid force along the y-axis was found to be -0.57 +/- 0.17 N. The maximum cross-coupling force in the x direction was found to be larger with a maximum value of 0.74 +/- 0.22 N. This resulted in a 25-35% overestimate of the radial fluid force as compared to the CFD predictions; this overestimation will lead to a far more robust magnetic suspension design. The axial and radial forces estimated from the computational results are well within a range over which a compact magnetic suspension can compensate for flow perturbations. This study also serves as an effective and novel design methodology for blood pump

  14. Polymeric heart valves for surgical implantation, catheter-based technologies and heart assist devices.

    Science.gov (United States)

    Bezuidenhout, Deon; Williams, David F; Zilla, Peter

    2015-01-01

    Efficient function and long-term durability without the need for anticoagulation, coupled with the ability to be accommodated in many different types of patient, are the principal requirements of replacement heart valves. Although the clinical use of valves appeared to have remained steady for several decades, the evolving demands for the elderly and frail patients typically encountered in the developed world, and the needs of much younger and poorer rheumatic heart disease patients in the developing world have now necessitated new paradigms for heart valve technologies and associated materials. This includes further consideration of durable elastomeric materials. The use of polymers to produce flexible leaflet valves that have the benefits of current commercial bioprosthetic and mechanical valves without any of their deficiencies has been held desirable since the mid 1950s. Much attention has been focused on thermoplastic polyurethanes in view of their generally good physico-chemical properties and versatility in processing, coupled with the improving biocompatibility and stability of recent formulations. Accelerated in vitro durability of between 600 and 1000 million cycles has been achieved using polycarbonate urethanes, and good resistance to degradation, calcification and thrombosis in vivo has been shown with some polysiloxane-based polyurethanes. Nevertheless, polymeric valves have remained relegated to use in temporary ventricular assist devices for bridging heart failure patients to transplantation. Some recent studies suggest that there is a greater degree of instability in thermoplastic materials than hitherto believed so that significant challenges remain in the search for the combination of durability and biocompatibility that would allow polymeric valves to become a clinical reality for surgical implantation. Perhaps more importantly, they could become candidates for use in situations where minimally invasive transcatheter procedures are used to

  15. Single-Center Experience With HeartMate II Left Ventricular Assist Device Explantation.

    Science.gov (United States)

    Tchantchaleishvili, Vakhtang; Cheyne, Christina; Sherazi, Saadia; Melvin, Amber L; Hallinan, William; Chen, Leway; Todd Massey, Howard

    2016-12-01

    In patients with continuous flow left ventricular assist devices (CF-LVADs) myocardial recovery is uncommon. Given the heterogeneity of the population implanted and low incidence of recovery, the discovery of native left ventricular (LV) recovery and criteria for explantation of CF-LVAD system is not clearly determined. We sought to analyze the characteristics of the patients who underwent CF-LVAD explantation at our institution. Prospectively collected data on patients supported with CF-LVADs were reviewed retrospectively. Patients who underwent CF-LVAD explants were identified and their characteristics were analyzed with a focus on patient presentation and determinants of explantability. From November 2006 to June 2014, 223 patients (181 male, 42 female) underwent implantation of HeartMate II LVAD. Seven female (16.7%) and one male (0.6%) patients were explanted (P < 0.001). Mean age was 43 ± 9 years and etiology for cardiomyopathy was ischemic in three (37.5%) patients, nonischemic in four (50%) patients, and mixed in the one (12.5%) male patient of the cohort. Five (62.5%) patients presented acutely with significant hemolysis, and were found to have LV improvement as well as reduced, absent, or reversed diastolic flow velocities on echocardiography. Overall, mean lactate dehydrogenase level before explantation was 1709 ± 1168 U/L compared to the mean baseline level of 601 ± 316 U/L (P = 0.048). Mean LV ejection fraction (LVEF) improved from 17 ± 7% preimplant to 56 ± 11% pre-explantation (P < 0.001). Median number of days on CF-LVAD support was 870 (interquartile range, 209-975) while mean duration of follow-up after the CF-LVAD explantation was 276 ± 240 days. Mean LVEF dropped from 46 ± 19% postexplantation to 34 ± 10% during the most recent follow-up (P = 0.015). At our institution, patients who underwent LVAD explants were predominantly women with nonischemic cardiomyopathy. Clinical evidence of

  16. Ventricular assist device support in patients with single ventricles: the Melbourne experience.

    Science.gov (United States)

    Poh, Chin L; Chiletti, Roberto; Zannino, Diana; Brizard, Christian; Konstantinov, Igor E; Horton, Stephen; Millar, Johnny; d'Udekem, Yves

    2017-08-01

    The capacity and limitations of ventricular assist device (VAD) support in single-ventricle physiology remains poorly understood. We aimed to review our experience in the use of VAD support in the single-ventricle circulation to determine its feasibility in this population. We reviewed our experience with VAD support in patients with single ventricles over the past 25 years. Fifty-seven patients received 64 runs of VAD support between 1990 and 2015 at a median age of 13 days [interquartile range (IQR) 4.1-99.4 days], of which 55 were supported for post-cardiotomy failure. The majority of patients received short-term VAD support, while 4 patients were either directly supported (1) or transitioned onto the Berlin Heart EXCOR (3). The median duration of support was 3.5 days (IQR 2.8-5.2 days). Twelve patients suffered significant neurological complications, and thromboembolic events occurred in 8 patients. Twenty-nine of the 55 patients were successfully weaned off support (53%). There were 37 inpatient deaths, with a survival-to-hospital discharge rate of 33% (18 of 55). Of the 4 patients supported after early Fontan failure, 3 died. Having a higher mean arterial blood pressure on initiation of VAD support was the only significant predictor of death (hazards ratio 1.08; 95% confidence interval 1.03-1.14; P = 0.002). Patients who required a second run of support had higher hospital mortality (83% vs 63%; P = 0.84). Of the hospital survivors, 12 patients (63%) remain alive without heart transplantation at median 7.2 years (IQR 3.5-14.0) post VAD support. VAD support in patients with a single ventricle has a high hospital mortality, with 1 of 3 patients surviving to discharge. Systemic VAD support is likely futile in the setting of early Fontan failure or when re-initiation of support is required. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  17. A modified Glenn shunt reduces right ventricular stroke work during left ventricular assist device therapy.

    Science.gov (United States)

    Schiller, Petter; Vikholm, Per; Hellgren, Laila

    2016-03-01

    Right ventricular (RV) failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) placement and remains hard to predict. We hypothesized that partial surgical exclusion of the RV with a modified Glenn shunt during LVAD treatment would reduce RV stroke work. An LVAD was implanted in eight pigs and a modified Glenn shunt was constructed. A conductance pressure-volume catheter was placed in the right ventricle through the apex. Haemodynamic data and pressure-volume loops were obtained at the following time periods: (i) baseline, (ii) open shunt, (iii) LVAD with closed shunt and (iii) LVAD and open shunt. During LVAD therapy, the right atrial (RA) pressure increased from 9 mmHg (9-9) to 15 mmHg (12-15), P = 0.01. RV stroke volume increased from 30 ml (29-40) to 51 ml (42-53), P < 0.01. Also, RV stroke work increased to 708 mmHg ml (654-1193) from 535 mmHg ml (424-717), P = 0.04, compared with baseline. During LVAD therapy in combination with a Glenn shunt, the RA pressure decreased from 15 mmHg (12-15) to 10 mmHg (7-11) when compared with LVAD therapy only, P = 0.01. A decrease in RV stroke work from 708 mmHg ml (654-1193) to 465 mmHg ml (366-711), P = 0.04, was seen when the LVAD was combined with a shunt, not significantly different from the baseline value (535 mmHg ml). The developed pressure in the right ventricle decreased from 29 mmHg (26-32) to 21 mmHg (20-24), P < 0.01. The pressure-volume loops of the RV show a significant reduction of RV stroke work during the use of the shunt with LVAD treatment. A modified Glenn shunt reduced RV volumes, RV stroke work and RA pressure during LVAD therapy in an experimental model of heart failure in pigs. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  18. Preliminary evaluation of rechargeable lithium cells for a totally-implantable ventricular assist device

    Science.gov (United States)

    MacLean, Gregory K.; Xin Shu, Zhi; Aiken, Peter A.; Eng, Isaac I.; Adams, William A.

    A preliminary evaluation of the performance characteristics for three types of rechargeable, 'AA' size, lithium cell chemistries, namely Li/TiS 2 (two different manufacturers), Li/MoS 2 and Li/MnO 2, was carried out in order to determine their potential usefulness in the internal (implanted) battery for the electrohydraulic ventricular assist device (EVAD) being developed. The major parameters studied at 37 °C were discharge rate capability, self-discharge and cycle life. The cycle life of the lithium cells above the minimum 30 min discharge time specified for EVAD were short, with the Li/MoS 2, Li/MnO 2 and two Li/TiS 2 cells giving 80, ˜ 11, 37 and 101 cycles, respectively, under pulsed discharge conditions. The 24 H, self-discharge study of all the cells at 37 °C showed < 1.2% decrease in capacity. Discharge rate studies showed that the Li/TiS 2 cells from both manufacturers offered higher observed specific energies (85 and 133 W h/kg) and energy densities (203 and 273 W h/l), lower internal resistances (155 and 84 mΩ) and larger observed capacities (0.83 and 1.00 A h) when compared to the Li/MoS 2 (49 W h/kg, 126 W h/l, 153 mΩ and 0.58 A h, respectively) and Li/MnO 2 (56 W h/kg, 131 W h/l, 350 mΩ and 0.39 A h, respectively) cells operating under average EVAD load conditions. The cycle life and operating times of cells that were pulse discharged to mimic actual EVAD operating conditions were shorter than those that underwent cycling with an average EVAD load. When compared to other energy sources and the EVAD design specification, it was concluded that none of these prototype lithium cells were currently suitable for use in the EVAD due to their low cycle life.

  19. Plasma assisted chemical vapor deposited tantalum silicon nitride thin films for applications in nanoscale devices

    Science.gov (United States)

    Zeng, Wanxue

    The scaling issues resulting from diminishing device feature sizes have prompted the investigation of alternative materials and deposition techniques for copper diffusion barrier applications. As device sizes shrink to sub 100-nm technology nodes, the allowable copper diffusion barrier thickness falls to less than 10 nm. In this respect, novel materials are needed to stop copper diffusion into surrounding materials. TaSiN has been regarded as one of the most promising materials for copper diffusion barrier applications, owing to its excellent thermal stability, amorphous structure, and low resistivity. In this respect, a plasma assisted chemical vapor deposition (PACVD) process using TaF5, SiI4, N2, H2, and in-situ radio frequency (RF) plasma was optimized for depositing ultrathin TaSiN films, employing a design of experiments (DOE) approach. Film properties were characterized using Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA), Auger electron spectroscopy (AES), x-ray diffraction (XRD), atomic force microscopy (AFM), four-point resistivity probe, and cross-section scanning electron microscopy (CS-SEM). The TaSiN films, deposited via optimized process conditions, exhibited low resistivity, low contamination levels, smooth surface morphology, good step coverage, excellent thermal stability, and amorphous structure. The copper diffusion barrier performance of optimized PACVD TaSiN films was assessed in Cu/TaSiN/Si structures using traditional high temperature annealing methods and in Cu/TaSiN/SiO2/Si structures using a triangular voltage sweep (TVS) method. The results from the former technique show that the diffusion barrier performance of TaSiN films with higher silicon concentration, corresponding to a more prevalent amorphous structure, leads to worse Cu diffusion barrier performance. The results from the TaSiN barrier testing also show that thinner TaSiN films (≤5 nm) performed better as Cu diffusion barriers than thicker Ta

  20. Individuals with Intellectual and/or Developmental Disabilities Use of Assistive Technology Devices in Support Provision

    Science.gov (United States)

    Bryant, Brian R.; Seok, Soonwha; Ok, Minwook; Bryant, Diane Pedrotty

    2012-01-01

    During a four-year period, from 1988-1992, two significant events occurred that greatly influenced assistive technology (AT) and intellectual disability: the passage by Congress of the Technology-Related Assistance for Individuals with Disabilities Act of 1988 and publication by the American Association on Intellectual and Development Disabilities…

  1. Automated stride assistance device improved the gait parameters and energy cost during walking of healthy middle-aged females but not those of young controls

    Science.gov (United States)

    Otsuki, Risa; Matsumoto, Hiromi; Ueki, Masaru; Uehara, Kazutake; Nozawa, Nobuko; Osaki, Mari; Hagino, Hiroshi

    2016-01-01

    [Purpose] The aim of this study was to clarify the effects of an automated stride assistance device on gait parameters and energy cost during walking performed by healthy middle-aged and young females. [Subjects and Methods] Ten middle-aged females and 10 young females were recruited as case and control participants, respectively. The participants walked for 3 minutes continuously under two different experimental conditions: with the device and without the device. Walking distance, mean walking speed, mean step length, cadence, walk ratio and the physiological cost index during the 3-minutes walk were measured. [Results] When walking with the stride assistance device, the step length and walk ratio of the middle-aged group were significantly higher than without it. Also, during walking without assistance from the device, the physiological cost index of the middle-aged group significantly increased; whereas during walking with assistance, there was no change. The intergroup comparison in the middle-aged group showed the physiological cost index was lower under the experimental condition with assistance provided, as opposed to the condition without the provision of assistance. [Conclusion] The results of this study show that the stride assistance device improved the gait parameters of the middle-aged group but not those of young controls. PMID:28174452

  2. The Resonating Arm Exerciser: design and pilot testing of a mechanically passive rehabilitation device that mimics robotic active assistance.

    Science.gov (United States)

    Zondervan, Daniel K; Palafox, Lorena; Hernandez, Jorge; Reinkensmeyer, David J

    2013-04-18

    Robotic arm therapy devices that incorporate actuated assistance can enhance arm recovery, motivate patients to practice, and allow therapists to deliver semi-autonomous training. However, because such devices are often complex and actively apply forces, they have not achieved widespread use in rehabilitation clinics or at home. This paper describes the design and pilot testing of a simple, mechanically passive device that provides robot-like assistance for active arm training using the principle of mechanical resonance. The Resonating Arm Exerciser (RAE) consists of a lever that attaches to the push rim of a wheelchair, a forearm support, and an elastic band that stores energy. Patients push and pull on the lever to roll the wheelchair back and forth by about 20 cm around a neutral position. We performed two separate pilot studies of the device. In the first, we tested whether the predicted resonant properties of RAE amplified a user's arm mobility by comparing his or her active range of motion (AROM) in the device achieved during a single, sustained push and pull to the AROM achieved during rocking. In a second pilot study designed to test the therapeutic potential of the device, eight participants with chronic stroke (35 ± 24 months since injury) and a mean, stable, initial upper extremity Fugl-Meyer (FM) score of 17 ± 8 / 66 exercised with RAE for eight 45 minute sessions over three weeks. The primary outcome measure was the average AROM measured with a tilt sensor during a one minute test, and the secondary outcome measures were the FM score and the visual analog scale for arm pain. In the first pilot study, we found people with a severe motor impairment after stroke intuitively found the resonant frequency of the chair, and the mechanical resonance of RAE amplified their arm AROM by a factor of about 2. In the second pilot study, AROM increased by 66% ± 20% (p = 0.003). The mean FM score increase was 8.5 ± 4 pts (p = 0.009). Subjects did not report

  3. The Resonating Arm Exerciser: design and pilot testing of a mechanically passive rehabilitation device that mimics robotic active assistance

    Science.gov (United States)

    2013-01-01

    Background Robotic arm therapy devices that incorporate actuated assistance can enhance arm recovery, motivate patients to practice, and allow therapists to deliver semi-autonomous training. However, because such devices are often complex and actively apply forces, they have not achieved widespread use in rehabilitation clinics or at home. This paper describes the design and pilot testing of a simple, mechanically passive device that provides robot-like assistance for active arm training using the principle of mechanical resonance. Methods The Resonating Arm Exerciser (RAE) consists of a lever that attaches to the push rim of a wheelchair, a forearm support, and an elastic band that stores energy. Patients push and pull on the lever to roll the wheelchair back and forth by about 20 cm around a neutral position. We performed two separate pilot studies of the device. In the first, we tested whether the predicted resonant properties of RAE amplified a user’s arm mobility by comparing his or her active range of motion (AROM) in the device achieved during a single, sustained push and pull to the AROM achieved during rocking. In a second pilot study designed to test the therapeutic potential of the device, eight participants with chronic stroke (35 ± 24 months since injury) and a mean, stable, initial upper extremity Fugl-Meyer (FM) score of 17 ± 8 / 66 exercised with RAE for eight 45 minute sessions over three weeks. The primary outcome measure was the average AROM measured with a tilt sensor during a one minute test, and the secondary outcome measures were the FM score and the visual analog scale for arm pain. Results In the first pilot study, we found people with a severe motor impairment after stroke intuitively found the resonant frequency of the chair, and the mechanical resonance of RAE amplified their arm AROM by a factor of about 2. In the second pilot study, AROM increased by 66% ± 20% (p = 0.003). The mean FM score increase was 8.5 ± 4 pts (p = 0

  4. LAPAROSCOPICALLY ASSISTED ANORECTOPLASTY AND THE USE OF THE BIPOLAR DEVICE TO SEAL THE RECTAL URINARY FISTULA.

    Science.gov (United States)

    Dutra, Robson Azevedo; Boscollo, Adriana Cartafina Perez

    2016-01-01

    The anorectal anomalies consist in a complex group of birth defects. Laparoscopic-assisted anorectoplasty improved visualization of the rectal fistula and the ability to place the pull-through segment within the elevator muscle complex with minimal dissection. There is no consensus on how the fistula should be managed. To evaluate the laparoscopic-assisted anorectoplasty and the treatment of the rectal urinary fistula by a bipolar sealing device. It was performed according to the original description by Georgeson1. Was used 10 mm infraumbilical access portal for 30º optics. The pneumoperitoneum was established with pressure 8-10 cm H2O. Two additional trocars of 5 mm were placed on the right and left of the umbilicus. The dissection started on peritoneal reflection using Ligasure(r). With the reduction in the diameter of the distal rectum was identified the fistula to the urinary tract. The location of the new anus was defined by the location of the external anal sphincter muscle complex, using electro muscle stimulator externally. Finally, it was made an anastomosis between the rectum and the new location of the anus. A Foley urethral probe was left for seven days. Seven males were operated, six with rectoprostatic and one with rectovesical fistula. The follow-up period ranged from one to four years. The last two patients operated underwent bipolar sealing of the fistula between the rectum and urethra without sutures or surgical ligation. No evidence of urethral leaks was identified. There are benefits of the laparoscopic-assisted anorectoplasty for the treatment of anorectal anomaly. The use of a bipolar energy source that seals the rectal urinary fistula has provided a significant decrease in the operating time and made the procedure be more elegant. As anomalias anorretais consistem de um grupo complexo de defeitos congênitos. A anorretoplastia laparoscópica permite melhor visualização da fístula retourinária e propicia o posicionamento do reto abaixado

  5. Analysis of cardiac ventricular wall motion based on a three-dimensional electromechanical biventricular model

    International Nuclear Information System (INIS)

    Xia Ling; Huo Meimei; Wei Qing; Liu Feng; Crozier, Stuart

    2005-01-01

    This paper describes a biventricular model, which couples the electrical and mechanical properties of the heart, and computer simulations of ventricular wall motion and deformation by means of a biventricular model. In the constructed electromechanical model, the mechanical analysis was based on composite material theory and the finite-element method; the propagation of electrical excitation was simulated using an electrical heart model, and the resulting active forces were used to calculate ventricular wall motion. Regional deformation and Lagrangian strain tensors were calculated during the systole phase. Displacements, minimum principal strains and torsion angle were used to describe the motion of the two ventricles. The simulations showed that during the period of systole (1) the right ventricular free wall moves towards the septum, and at the same time, the base and middle of the free wall move towards the apex, which reduces the volume of the right ventricle; the minimum principle strain (E3) is largest at the apex, then at the middle of the free wall and its direction is in the approximate direction of the epicardial muscle fibres; (2) the base and middle of the left ventricular free wall move towards the apex and the apex remains almost static; the torsion angle is largest at the apex; the minimum principle strain E3 is largest at the apex and its direction on the surface of the middle wall of the left ventricle is roughly in the fibre orientation. These results are in good accordance with results obtained from MR tagging images reported in the literature. This study suggests that such an electromechanical biventricular model has the potential to be used to assess the mechanical function of the two ventricles, and also could improve the accuracy of ECG simulation when it is used in heart-torso model-based body surface potential simulation studies

  6. Substrate type < 111 >-Cu{sub 2}O/<0001 >-ZnO photovoltaic device prepared by photo-assisted electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Zamzuri, Mohd, E-mail: zamzuri@tf.me.tut.ac.jp [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); School of Manufacturing Eng., Universiti Malaysia Perlis, Kampus Tetap Pauh Putra, Jln Arau-Changlun, 02600 Arau, Perlis (Malaysia); Sasano, Junji [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); Mohamad, Fariza Binti [Faculty of Electrical & Electronic Eng., University Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor (Malaysia); Izaki, Masanobu [Department of Mechanical Eng., Toyohashi University of Technology, 1-1 Hibari Gaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan)

    2015-11-30

    The substrate-type < 0001 > ZnO/<111 > Cu{sub 2}O photovoltaic (PV) device has been constructed by electrodeposition of a < 111 >-p-Cu{sub 2}O layer on an Au(111)/Si wafer substrate followed by stacking the n-ZnO layer by electrodeposition during light irradiation in aqueous solutions. The PV device was fabricated by stacking the Al:ZnO-window by sputtering and the top Al electrode by vacuum evaporation. The < 0001 >-ZnO layer was composed of aggregates of hexagonal columnar grains grown in the direction normal to the surface, and pores could be observed between the ZnO grains at the deposition time last 1800 s. The < 0001 >-ZnO/<111 >-Cu{sub 2}O PV device showed a photovoltaic performance under AM1.5 illumination, and showed the improved short-circuit current density of 5.87 mA cm{sup −2} by stacking the AZO-TCO due to the increase in the diffusion length of the carrier. - Highlights: • Substrate type ZnO/Cu{sub 2}O photovoltaic devices only by electrodeposition • ZnO layer was stacked on the Cu{sub 2}O layer by photo-assisted electrodeposition. • AZO/ZnO/Cu{sub 2}O photovoltaic devices with a short-circuit current density of 5.87 mA cm{sup −2}.

  7. Changes of Sympathetic Activity in Patient with Chronic Atrial Fibrillation and Severe Congestive Heart Failure Treated with Biventricular Pacing

    Directory of Open Access Journals (Sweden)

    Kohei Matsushita, MD

    2006-01-01

    Full Text Available The patient was a 64-year-old man with chronic atrial fibrillation with bradycardia. Left ventricular ejection fraction was 34%. He was treated with biventricular pacing. Heart failure improved from NYHA class III to II. Sympathetic nerve activity (SNA. was recorded during 6 minutes of biventricular (BV, right ventricular apical (RVA. and left ventricular (LV. pacing. SNA was significantly lower during biventricular pacing (49.5 ± 4.0/min. compared with RVA (58.8 ±6:9/min, p = 0.016. and LV (63.3 ± 4.3/min, p = 0.002. pacing. BV pacing improves hemodynamics and decreases SNA compared with RVA or LV pacing.

  8. The pharmacotherapy of the HeartMate II, a continuous flow left ventricular assist device, in patients with advanced heart failure: integration of disease, device, and drug.

    Science.gov (United States)

    Jennings, Douglas L; Chambers, Rachel M; Schillig, Jessica M

    2010-10-01

    Advanced heart failure continues to be a significant cause of morbidity and mortality in the US. Patients with advanced heart failure have a poor prognosis without cardiac transplantation. The use of left ventricular assist devices (LVADs) as destination therapy for these patients is therefore expected to increase in the coming years as technology advances. The HeartMate II, a continuous flow implantable device, is currently the only LVAD that has been approved by the Food and Drug Administration for destination therapy in patients with advanced heart failure. The pharmacotherapy associated with this device is very complex and, therefore, the need for expertly trained clinical pharmacists to care for this expanding patient population will also likely increase. Unfortunately, most pharmacists are unfamiliar with the effect of LVADs on the physiology and pharmacotherapy of a patient's heart failure. The purpose of this article is to give clinical pharmacists an introduction to the most common pharmacotherapeutic issues for patients with LVADs and present practical solutions for managing common drug therapy problems.

  9. Hybrid approach of ventricular assist device and autologous bone marrow stem cells implantation in end-stage ischemic heart failure enhances myocardial reperfusion

    Directory of Open Access Journals (Sweden)

    Khayat Andre

    2011-01-01

    Full Text Available Abstract We challenge the hypothesis of enhanced myocardial reperfusion after implanting a left ventricular assist device together with bone marrow mononuclear stem cells in patients with end-stage ischemic cardiomyopathy. Irreversible myocardial loss observed in ischemic cardiomyopathy leads to progressive cardiac remodelling and dysfunction through a complex neurohormonal cascade. New generation assist devices promote myocardial recovery only in patients with dilated or peripartum cardiomyopathy. In the setting of diffuse myocardial ischemia not amenable to revascularization, native myocardial recovery has not been observed after implantation of an assist device as destination therapy. The hybrid approach of implanting autologous bone marrow stem cells during assist device implantation may eventually improve native cardiac function, which may be associated with a better prognosis eventually ameliorating the need for subsequent heart transplantation. The aforementioned hypothesis has to be tested with well-designed prospective multicentre studies.

  10. Soft robotic devices for hand rehabilitation and assistance: a narrative review.

    Science.gov (United States)

    Chu, Chia-Ye; Patterson, Rita M

    2018-02-17

    The debilitating effects on hand function from a number of a neurologic disorders has given rise to the development of rehabilitative robotic devices aimed at restoring hand function in these patients. To combat the shortcomings of previous traditional robotics, soft robotics are rapidly emerging as an alternative due to their inherent safety, less complex designs, and increased potential for portability and efficacy. While several groups have begun designing devices, there are few devices that have progressed enough to provide clinical evidence of their design's therapeutic abilities. Therefore, a global review of devices that have been previously attempted could facilitate the development of new and improved devices in the next step towards obtaining clinical proof of the rehabilitative effects of soft robotics in hand dysfunction. A literature search was performed in SportDiscus, Pubmed, Scopus, and Web of Science for articles related to the design of soft robotic devices for hand rehabilitation. A framework of the key design elements of the devices was developed to ease the comparison of the various approaches to building them. This framework includes an analysis of the trends in portability, safety features, user intent detection methods, actuation systems, total DOF, number of independent actuators, device weight, evaluation metrics, and modes of rehabilitation. In this study, a total of 62 articles representing 44 unique devices were identified and summarized according to the framework we developed to compare different design aspects. By far, the most common type of device was that which used a pneumatic actuator to guide finger flexion/extension. However, the remainder of our framework elements yielded more heterogeneous results. Consequently, those results are summarized and the advantages and disadvantages of many design choices as well as their rationales were highlighted. The past 3 years has seen a rapid increase in the development of soft robotic

  11. Significance of Residual Mitral Regurgitation After Continuous Flow Left Ventricular Assist Device Implantation.

    Science.gov (United States)

    Kassis, Hayah; Cherukuri, Krishna; Agarwal, Richa; Kanwar, Manreet; Elapavaluru, Subbarao; Sokos, George G; Moraca, Robert J; Bailey, Stephen H; Murali, Srinivas; Benza, Raymond L; Raina, Amresh

    2017-02-01

    This study hypothesized that the presence of residual mitral regurgitation (MR) post-continuous flow (CF) left ventricular assist device (LVAD) implantation based on quantitative assessment would be negatively associated with right ventricular (RV) size and function and clinical outcomes. MR is associated with elevated left atrial pressure, secondary pulmonary hypertension and RV dysfunction. Implantation of a LVAD leads to mechanical unloading of the left ventricle and generally improves MR. The clinical significance of residual MR in patients supported with CF LVADs is uncertain. Most studies evaluating the presence of MR in LVAD patients have utilized predominantly qualitative assessments of MR. We retrospectively identified patients implanted with CF LVADs at our institution from 2007 to 2013 who had a pre-operative transthoracic echocardiogram (TTE) within 3 months of LVAD implant and who had a post-operative TTE at least 1 month post-LVAD. MR was assessed quantitatively using the ratio of MR color jet area (CJA)/left atrial area (LAA) in apical views. We also compared quantitative RV metrics, hospitalizations, and mortality in patients with and without significant residual MR (defined as MR CJA/LAA >0.2) on post-implantation TTE. Sixty-nine patients were included in this study. Post-LVAD implantation, 55 patients (80%) had mild or less MR (mean MR CJA/LAA 0.08) but 14 (20%) had significant residual MR (mean MR CJA/LAA 0.34). Patients with residual MR had significantly larger RV size (right ventricular end diastolic dimension 49 mm vs. 45 mm; p = 0.04) and worse RV function (tricuspid annular plane systolic excursion 10 mm vs. 12 mm; p = 0.02; and right ventricular fractional area change 29% vs. 34%; p = 0.02). Post-implantation pulmonary artery pressures were higher in patients with residual MR (pulmonary artery systolic 43 mm Hg vs. 35 mm Hg; p = 0.05). In patients with residual MR there was slightly greater posterior displacement of the mitral

  12. Liquid phase solvent bonding of plastic microfluidic devices assisted by retention grooves.

    Science.gov (United States)

    Wan, Alwin M D; Sadri, Amir; Young, Edmond W K

    2015-01-01

    We report a novel method for achieving consistent liquid phase solvent bonding of plastic microfluidic devices via the use of retention grooves at the bonding interface. The grooves are patterned during the regular microfabrication process, and can be placed at the periphery of a device, or surrounding microfluidic features with open ports, where they effectively mitigate solvent evaporation, and thus substantially reduce poor bond coverage. This method is broadly applicable to a variety of plastics and solvents, and produces devices with high bond quality (i.e., coverage, strength, and microfeature fidelity) that are suitable for studies in physics, chemistry, and cell biology at the microscale.

  13. Concurrent use of continuous and pulsatile flow Ventricular Assist Device on a fontan patient: A simulation study.

    Science.gov (United States)

    Di Molfetta, Arianna; Ferrari, Gianfranco; Iacobelli, Roberta; Filippelli, Sergio; Amodeo, Antonio

    2017-01-01

    The aim of this work is to develop and test a lumped parameter model of the cardiovascular system to simulate the concurrent use of pulsatile (PVAD) and continuous flow (CVAD) ventricular assist device (VAD) on Fontan patients. Echocardiographic and hemodynamic data of five Fontan patients were retrospectively collected and used to simulate the patients' baseline hemodynamics. Then, for each patient, the following assistance modality was simulated for the cavopulmonary and the single ventricle (SV): (a) CVAD for cavopulmonary assistance (RCF) and PVAD assisting the SV (LCF) (RPF + LCF), (b) CVAD assisting SV and PVAD for cavopulmonary assistance (LPF + RCF). The numerical model can well reproduce patients' baseline. The cardiac output increases more importantly in the LCF + RPF configuration (35 vs. 8%). Ventricular volume decreases more evidently in the configuration LCF + RPF (28 vs. 6%), atrial pressure decreases in the LCF + RPF modality (10%), while it slightly increases in the RCF + LPF modality. The pulmonary arterial pressure slightly decreases (increases) in the configuration RCF + LPF (LCF + RPF). Ventricular external work increases in both configurations because of the total increment of the cardiac output. However, artero-ventricular coupling improves in both configurations: RCF + LPF-14%, LCF + RPF-41%. The pulsatility index decreases (increases) by 8% (13.8%) in the configuration LCF + RPF (RCF + LPF). A model could permit us to simulate extreme physiological conditions of the implantation of both CF and PF VAD on the Fontan patient and could permit to choose the proper VAD on the base of patients' condition. The configuration LCF + RPF seems to maximize the hemodynamic benefits. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  14. Laser-Assisted Simultaneous Transfer and Patterning of Vertically Aligned Carbon Nanotube Arrays on Polymer Substrates for Flexible Devices

    KAUST Repository

    In, Jung Bin

    2012-09-25

    We demonstrate a laser-assisted dry transfer technique for assembling patterns of vertically aligned carbon nanotube arrays on a flexible polymeric substrate. A laser beam is applied to the interface of a nanotube array and a polycarbonate sheet in contact with one another. The absorbed laser heat promotes nanotube adhesion to the polymer in the irradiated regions and enables selective pattern transfer. A combination of the thermal transfer mechanism with rapid direct writing capability of focused laser beam irradiation allows us to achieve simultaneous material transfer and direct micropatterning in a single processing step. Furthermore, we demonstrate that malleability of the nanotube arrays transferred onto a flexible substrate enables post-transfer tailoring of electric conductance by collapsing the aligned nanotubes in different directions. This work suggests that the laser-assisted transfer technique provides an efficient route to using vertically aligned nanotubes as conductive elements in flexible device applications. © 2012 American Chemical Society.

  15. Assistive Devices for People with Hearing, Voice, Speech, or Language Disorders

    Science.gov (United States)

    ... simplest AAC device is a picture board or touch screen that uses pictures or symbols of typical items ... a person’s age, education, occupation, and interests. Keyboards, touch screens, and sometimes a person’s limited speech may be ...

  16. The Effect of the Usage of Computer-Based Assistive Devices on the Functioning and Quality of Life of Individuals Who Are Blind or Have Low Vision

    Science.gov (United States)

    Rosner, Yotam; Perlman, Amotz

    2018-01-01

    Introduction: The Israel Ministry of Social Affairs and Social Services subsidizes computer-based assistive devices for individuals with visual impairments (that is, those who are blind or have low vision) to assist these individuals in their interactions with computers and thus to enhance their independence and quality of life. The aim of this…

  17. Massive Atenolol, Lisinopril, and Chlorthalidone Overdose Treated with Endoscopic Decontamination, Hemodialysis, Impella Percutaneous Left Ventricular Assist Device, and ECMO.

    Science.gov (United States)

    Heise, C William; Beutler, David; Bosak, Adam; Orme, Geoffrey; Loli, Akil; Graeme, Kimberlie

    2015-03-01

    Overdose of cardiovascular medications is increasingly associated with morbidity and mortality. We present a case of substantial atenolol, chlorthalidone, and lisinopril overdose treated by multiple modalities with an excellent outcome. Aggressive medical intervention did not provide sufficient hemodynamic stability in this patient with refractory cardiogenic and distributive shock. Impella® percutaneous left ventricular assist device and extracorporeal membrane oxygenation provided support while the effects of the overdose subsided. We present concentrations demonstrating removal of atenolol with continuous venovenous hemodiafiltration. This is the first report of esophagogastroduo denoscopy decontamination of this overdose with a large pill fragment burden.

  18. Fluoroscopy-Guided Resolution of Ingested Thrombus Leading to Functional Disturbance of a Continuous-Flow Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Jens Garbade

    2012-01-01

    Full Text Available The third generation of left ventricular assist devices (LVADs has been shown to improve outcome and quality of life in patients suffering from acute and chronic heart failure. However, VAD-associated complications are still a challenge in the clinical practice. Here we report the resolution of a mobile thrombus formation in the proximity of the inflow cannula of a third generation of LVADs (HVAD Pump, HeartWare, Inc. in a patient with chronic heart failure 4 months after implantation.

  19. A Case of Cough-induced Ventricular Tachycardia in a Patient with a Left Ventricular Assist Device.

    Science.gov (United States)

    Ruckdeschel, Emily Sue; Wolfel, Eugene; Nguyen, Duy Thai

    2016-03-01

    In this case, the patient's ventricular tachycardia (VT) was specifically induced by coughing, which has not previously been described. Decreasing the rotational speed of the left ventricular assist device (LVAD) and increasing preload by stopping the patient's nitrates and reducing diuretic dose allowed improved filling of the left ventricle (LV) and increased LV volumes. When coughing recurred, the effects on the LV cavity were less pronounced and thus VT was reduced. Although ventricular arrhythmias are common after LVAD placement, this is a unique case in which VT was caused by coughing, which is ordinarily not considered arrhythmogenic. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. A wafer-scale backplane-assisted resonating nanoantenna array SERS device created by tunable thermal dewetting nanofabrication

    Science.gov (United States)

    Chang, Te-Wei; Ranjan Gartia, Manas; Seo, Sujin; Hsiao, Austin; Logan Liu, Gang

    2014-04-01

    A tunable lithography-less nanofabrication process using a metal thin-film thermal dewetting technique has been developed to fabricate wafer-scale and uniform plasmonic substrates at low cost for optimal performance in surface enhanced Raman scattering (SERS) applications. The relationship between the tunable parameters of this process and the corresponding optical and plasmonic characteristic is investigated both experimentally and theoretically to understand the deterministic design of an optimal SERS device with a three-dimensional plasmonic nanoantenna structure. The enhancement of SERS using various nanoplasmonic particle sizes, structure lengths, lateral hot spot spacings and resonating effects are examined and demonstrated. We achieve a uniform optimal enhancement factor of 1.38 × 108 on a 4 in wafer-scale SERS substrate with a backplane-assisted resonating nanoantenna array design. Sensitive environmental nitrate sensing, vitamin detection and oligonucleotide identification are demonstrated on the high-performance SERS device.

  1. Electronic and optical device applications of hollow cathode plasma assisted atomic layer deposition based GaN thin films

    International Nuclear Information System (INIS)

    Bolat, Sami; Tekcan, Burak; Ozgit-Akgun, Cagla; Biyikli, Necmi; Okyay, Ali Kemal

    2015-01-01

    Electronic and optoelectronic devices, namely, thin film transistors (TFTs) and metal–semiconductor–metal (MSM) photodetectors, based on GaN films grown by hollow cathode plasma-assisted atomic layer deposition (PA-ALD) are demonstrated. Resistivity of GaN thin films and metal-GaN contact resistance are investigated as a function of annealing temperature. Effect of the plasma gas and postmetallization annealing on the performances of the TFTs as well as the effect of the annealing on the performance of MSM photodetectors are studied. Dark current to voltage and responsivity behavior of MSM devices are investigated as well. TFTs with the N 2 /H 2 PA-ALD based GaN channels are observed to have improved stability and transfer characteristics with respect to NH 3 PA-ALD based transistors. Dark current of the MSM photodetectors is suppressed strongly after high-temperature annealing in N 2 :H 2 ambient

  2. Advances in Continuous Flow Left Ventricular Assist Device Support for End-Stage Heart Failure: A Therapy in Evolution.

    Science.gov (United States)

    Saeed, Omar; Jorde, Ulrich P

    The purpose of this review is to highlight recent advances and challenges in the clinical implementation of continuous flow left ventricular assist devices (CF LVADs) in patients with advanced heart failure. Post approval studies of CF LVAD therapy continue to show a progressive improvement in survival and reduction in adverse events. Major trials are ongoing to compare outcomes of an axial flow device (Heart Mate II) and smaller centrifugal flow pumps (HeartWare VADs and Heart Mate III). Numerous studies have investigated strategies to reduce major hematologic and neurologic adverse events by evaluating hemolysis, antithrombotic therapy, and blood pressure control. This review will present the current findings that are centered around the impact of CF LVADs on improving survival and reducing adverse events through an evolution in management and design.

  3. Integrated SDS removal and protein digestion by hollow fiber membrane based device for SDS-assisted proteome analysis.

    Science.gov (United States)

    Xia, Simin; Yuan, Huiming; Chen, Yuanbo; Liang, Zheng; Zhang, Lihua; Zhang, Yukui

    2015-08-15

    In this work, a novel integrated sample preparation device for SDS-assisted proteome analysis was developed, by which proteins dissolved in 4% (w/v) SDS were first diluted by 50% methanol, and then SDS was online removed by a hollow fiber membrane interface (HFMI) with 50mM ammonium bicarbonate (pH 8.0) as an exchange buffer, finally digested by an immobilized enzyme reactor (IMER). To evaluate the performance of such an integrated device, bovine serum albumin dissolved in 4% (w/v) SDS as a model sample was analyzed; it could be found that similar to that obtained by direct analysis of BSA digests without SDS (the sequence coverage of 60.3±1.0%, n=3), with HFMI as an interface for SDS removal, BSA was identified with the sequence coverage of 61.0±1.0% (n=3). However, without SDS removal by HFMI, BSA could not be digested by the IMER and none peptides could be detected. In addition, such an integrated sample preparation device was also applied for the analysis of SDS extracted proteins from rat brain, compared to those obtained by filter-aided sample preparation (FASP), not only the identified protein group and unique peptide number were increased by 12% and 39% respectively, but also the sample pretreatment time was shortened from 24h to 4h. All these results demonstrated that such an integrated sample preparation device would provide an alternative tool for SDS assisted proteome analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Provision of assistive technology devices among people with ALS in Germany: a platform-case management approach.

    Science.gov (United States)

    Funke, Andreas; Spittel, Susanne; Grehl, Torsten; Grosskreutz, Julian; Kettemann, Dagmar; Petri, Susanne; Weyen, Ute; Weydt, Patrick; Dorst, Johannes; Ludolph, Albert C; Baum, Petra; Oberstadt, Moritz; Jordan, Berit; Hermann, Andreas; Wolf, Joachim; Boentert, Matthias; Walter, Bertram; Gajewski, Nadine; Maier, André; Münch, Christoph; Meyer, Thomas

    2018-01-30

    The procurement of assistive technology devices (ATD) is an essential component of managed care in ALS. The objective was to analyze the standards of care for ATD and to identify challenges in the provision process. A cohort study design was used. We investigated the provision of 11,364 ATD in 1494 patients with ALS at 12 ALS centers in Germany over four years. Participants were patients that entered a case management program for ATD including systematic assessment of ATD on a digital management platform. Wheelchairs (requested in 65% of patients), orthoses (52%), bathroom adaptations (49%), and communication devices (46%) were the most needed ATD. There was a wide range in the number of indicated ATD per patient: 1 to 4 ATD per patient in 45% of patients, 5 to 20 ATD in 48%, and >20 ATD in 7% of patients. Seventy percent of all requested ATD were effectively delivered. However, an alarming failure rate during procurement was found in ATD that are crucial for ALS patients such as powered wheelchairs (52%), communication devices (39%), or orthoses (21%). Leading causes for not providing ATD were the refusal by health insurances, the decision by patients, and the death of the patient before delivery of the device. The need for ATD was highly prevalent among ALS patients. Failed or protracted provision posed substantial barriers to ATD procurement. Targeted national strategies and the incorporation of ATD indication criteria in international ALS treatment guidelines are urgently needed to overcome these barriers.

  5. Is hydrotherapy an appropriate form of exercise for elderly patients with biventricular systolic heart failure?

    Science.gov (United States)

    Sveälv, Bente Grüner; Täng, Margareta Scharin; Cider, Åsa

    2012-01-01

    Hydrotherapy (exercise in warm water) is considered to be a safe and beneficial method to use in the rehabilitation of stable heart failure patients, but there is little information on the effect of the increased venous return and enhanced preload in elderly patients with biventricular heart failure. We present a case of an elderly man who was recruited to participate in a hydrotherapy study. We compared echocardiographic data during warm water immersion with land measurements, and observed increases in stroke volume from 32 mL (land) to 42 mL (water), left ventricular ejection fraction from 22% to 24%, left ventricular systolic velocity from 4.8 cm/s to 5.0 cm/s and left atrioventricular plane displacement from 2.1 mm to 2.2 mm. By contrast, right ventricular systolic velocity decreased from 11.2 cm/s to 8.4 cm/s and right atrioventricular plane displacement from 8.1 mm to 4.7 mm. The tricuspid pressure gradient rose from 18 mmHg on land to 50 mmHg during warm water immersion. Thus, although left ventricular systolic function was relatively unaffected during warm water immersion, we observed a decrease in right ventricular function with an augmented right ventricular pressure. We recommend further investigations to observe the cardiac effect of warm water immersion on patients with biventricular systolic heart failure and at risk of elevated right ventricular pressure. PMID:23341846

  6. Concurrent Left Ventricular Assist Device (LVAD) Implantation and Percutaneous Temporary RVAD Support via CardiacAssist Protek-Duo TandemHeart to Preempt Right Heart Failure

    Science.gov (United States)

    Schmack, Bastian; Weymann, Alexander; Popov, Aron-Frederik; Patil, Nikhil Prakash; Sabashnikov, Anton; Kremer, Jamila; Farag, Mina; Brcic, Andreas; Lichtenstern, Christoph; Karck, Matthias; Ruhparwar, Arjang

    2016-01-01

    Right ventricular failure (RVF) is an unfortunate complication that continues to limit outcomes following durable left ventricular assist device (LVAD) implantation. Despite several ‘RVF risk scores’ having been proposed, preoperative prediction of post-LVAD RVF remains a guesstimate at best. Current strategies for institution of temporary RVAD support are invasive, necessitate additional re-thoracotomy, restrict postoperative mobilization, and/or entail prolonged retention of prosthetic material in-situ. The authors propose a novel surgical strategy comprising simultaneous implantation of a permanent LVAD and percutaneous TandemHeart® plus ProtekDuo® to provide temporary RVAD support and preempt RVF in patients with impaired RV function. PMID:27145697

  7. Toxicity testing of human assisted reproduction devices using the mouse embryo assay.

    NARCIS (Netherlands)

    Punt-Van der Zalm, J.P.; Hendriks, J.C.M.; Westphal, J.R.; Kremer, J.A.M.; Teerenstra, S.; Wetzels, A.M.M.

    2009-01-01

    Systems to assess the toxicity of materials used in human assisted reproduction currently lack efficiency and/or sufficient discriminatory power. The development of 1-cell CBA/B6 F1 hybrid mouse embryos to blastocysts, expressed as blastocyst rate (BR), is used to measure toxicity. The embryos were

  8. A Practical Hardware-Assisted Approach to Customize Trusted Boot for Mobile Devices

    DEFF Research Database (Denmark)

    Gonzalez, Javier; Hölzl, Michael; Riedl, Peter

    2014-01-01

    Current efforts to increase the security of the boot sequence for mobile devices fall into two main categories: (i) secure boot: where each stage in the boot sequence is evaluated, aborting the boot process if a non expected component attempts to be loaded; and (ii) trusted boot: where a log...... their security requirements. This is a first step towards supporting usage control primitives for running applications. Our approach relies on off-the-shelf secure hardware that is available in a multitude of mobile devices: ARM TrustZone as a Trusted Execution Environment, and Secure Element as a tamper...... is maintained with the components that have been loaded in the boot process for later audit. The first approach is often criticized for locking down devices, thus reducing users’ freedom to choose software. The second lacks the mechanisms to enforce any form of run-time verification. In this paper, we present...

  9. Introducing a device to assist in the application of anti-embolism stockings.

    Science.gov (United States)

    Thomas, Nicola; Bennett, Neomi

    2017-05-11

    Using a device to help with the application and removal of anti-embolism stockings, often called thromboembolic deterrent stockings (TEDS), can potentially facilitate greater adherence to the use of stockings, and potentially reduce the risk of deep-vein thrombosis (DVT). This article describes a quality improvement project which used the Plan, Do, Study, Act (PDSA) cycle to facilitate the introduction of a device to aid in the application of thromboembolic deterrent stockings in an orthopaedic ward. The project findings showed that Neo-slip®, a product designed to facilitate the use of compression stockings, can be effectively introduced into an orthopaedic ward, with positive feedback from both staff and patients.

  10. Engineered embodiment: Comment on "The embodiment of assistive devices-from wheelchair to exoskeleton" by M. Pazzaglia and M. Molinari

    Science.gov (United States)

    Kannape, Oliver Alan; Lenggenhager, Bigna

    2016-03-01

    From brain-computer interfaces to wearable robotics and bionic prostheses - intelligent assistive devices have already become indispensable in the therapy of people living with reduced sensorimotor functioning of their physical body, be it due to spinal cord injury, amputation or brain lesions [1]. Rapid technological advances will continue to fuel this field for years to come. As Pazzaglia and Molinari [2] rightly point out, progress in this domain should not solely be driven by engineering prowess, but utilize the increasing psychological and neuroscientific understanding of cortical body-representations and their plasticity [3]. We argue that a core concept for such an integrated embodiment framework was introduced with the formalization of the forward model for sensorimotor control [4]. The application of engineering concepts to human movement control paved the way for rigorous computational and neuroscientific analysis. The forward model has successfully been adapted to investigate principles underlying aspects of bodily awareness such as the sense of agency in the comparator framework [5]. At the example of recent advances in lower limb prostheses, we propose a cross-disciplinary, integrated embodiment framework to investigate the sense of agency and the related sense of body ownership for such devices. The main onus now is on the engineers and cognitive scientists to embed such an approach into the design of assistive technology and its evaluation battery.

  11. In vivo biocompatibility evaluation of a new resilient, hard-carbon, thin-film coating for ventricular assist devices.

    Science.gov (United States)

    Takaseya, Tohru; Fumoto, Hideyuki; Shiose, Akira; Arakawa, Yoko; Rao, Santosh; Horvath, David J; Massiello, Alex L; Mielke, Nicole; Chen, Ji-Feng; Zhou, Qun; Dessoffy, Raymond; Kramer, Larry; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

    2010-12-01

    The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  12. The effect of an on-body personal lift assist device (PLAD) on fatigue during a repetitive lifting task.

    Science.gov (United States)

    Lotz, Christy A; Agnew, Michael J; Godwin, Alison A; Stevenson, Joan M

    2009-04-01

    Occupations demanding frequent and heavy lifting are associated with an increased risk of injury. A personal lift assist device (PLAD) was designed to assist human muscles through the use of elastic elements. This study was designed to determine if the PLAD could reduce the level of general and local back muscle fatigue during a cyclical lifting task. Electromyography of two erector spinae sites (T9 and L3) was recorded during a 45-min lifting session at six lifts/lowers per minute in which male participants (n=10) lifted a box scaled to represent 20% of their maximum back extensor strength. The PLAD device reduced the severity of muscular fatigue at both muscle sites. RMS amplitude increased minimally (22% and 26%) compared to the no-PLAD condition (104% and 88%). Minimal median frequency decreases (0.33% and 0.41%) were observed in the PLAD condition compared to drops of 12% and 20% in the no-PLAD condition. The PLAD had an additional benefit of minimizing pre-post changes in muscular strength and endurance. The PLAD also resulted in a significantly lower rate of perceived exertion across the lifting session. It was concluded that the PLAD was effective at decreasing the level of back muscular fatigue.

  13. Motion artifacts in cardiac CT. The Novacor left ventricular assist device and its implications for clinical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Knollman, F.D. [Strahlenklinik, Charite, Campus Virchow-Klinikum, Medizinische Fakultaet der Humboldt-Univ. zu Berlin (Germany); Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Deutsches Herzzentrum Berlin (Germany); Halfmann, R. [Baxter Deutschland GmbH, Unterschleissheim (Germany); Regn, J. [Siemens AG Bereich Medizin, Erlangen (Germany); Loebe, M.; Ewert, R.; Hetzer, R. [Klinik fuer Herz-, Thorax- und Gefaesschirurgie, Deutsches Herzzentrum Berlin (Germany); Felix, R. [Strahlenklinik, Charite, Campus Virchow-Klinikum, Medizinische Fakultaet der Humboldt-Univ. zu Berlin (Germany)

    1999-11-01

    Purpose: Cardiovascular applications of CT are primarily limited by temporal resolution of the scanner. Recent development in scanner technology has greatly increased temporal resolution. We here describe a standardized method of assessing temporal properties of various CT techniques. Material and Methods: The Novacor left ventricular assist device was mounted in a water-filled circulation phantom and scanned at different pump rates with a spiral CT unit and an electron beam unit. We also evaluated the use of ECG-triggered subsecond scanning on a spiral CT unit. Results: Using the fastest conventional scanning protocol, severe motion artifacts occurred. These artifacts could not be reproduced from image to image, even if the pump rate was adjusted to scan rate (1/s). Electron beam tomography (EBT) reproducibly yielded few artifacts at 100 ms and practically no artifacts at 50 ms scanning time. Even without ECG-triggering, pump motion could be reproduced as a cine-cycle. With the ECG-triggered partial scanning CT technique, limited motion artifacts could be reproduced during diastole at a heart rate of 70-80 beats/min. Conclusion: The Novacor ventricular assist device may serve as a benchmark test in the evaluation of new scanning techniques for cardiovascular CT. While EBT presently remains the only CT technique to freeze cardiac motion throughout its cycle, ECG-triggered subsecond scans may, under certain conditions, capture cardiac anatomy in diastole. (orig.)

  14. Hemodynamic changes during left ventricular assist device-off test correlate with the degree of cardiac fibrosis and predict the outcome after device explantation.

    Science.gov (United States)

    Saito, Shunsuke; Toda, Koichi; Miyagawa, Shigeru; Yoshikawa, Yasushi; Fukushima, Satsuki; Sakata, Yasushi; Mizote, Isamu; Daimon, Takashi; Sawa, Yoshiki

    2015-03-01

    Myocardial recovery occurs in a small cohort of patients receiving left ventricular assist device (LVAD) support, but identification of candidates for device removal remains challenging. We hypothesized that hemodynamic evaluation using echocardiography and right heart catheter during temporary suspension of LVAD support (LVAD-off test) can assess cardiac recovery to predict successful device removal. To prove this hypothesis, we reviewed 44 patients who underwent LVAD-off test from January 2000 to March 2011 at Osaka University Hospital. Twenty-two of them underwent LVAD explant, 9 showed sustaining recovery (successful explant, SE-group); whereas 13 had a recurrent heart failure (failed explant, FE-group). The other 22 patients remained LVAD dependent (nonrecovery, NR-group). Echocardiography showed significant lower ejection fraction (LVEF) in NR-group than in SE- and FE-group after termination of LVAD support, but there was no difference between SE- and FE-group. On the other hand, elevation in pulmonary capillary wedge pressure (ΔPCWP) was significantly smaller in SE-group than in FE- and NR-groups. The degree of cardiac fibrosis significantly increased in FE- and NR-group during the LVAD support, while it did not increase in SE-group. The degree of cardiac fibrosis at the time of LVAD explantation correlated significantly with PCWP at LVAD halt and ΔPCWP, and it had significant impact on the outcome after LVAD weaning. In conclusion, the data obtained during LVAD-off test using echocardiography and right heart catheter significantly correlated with the degree of cardiac fibrosis at the time of LVAD explantation. LVAD-off test is a useful method to predict the successful LVAD explantation.

  15. Advanced laser-based tracking device for motor vehicle lane position monitoring and steering assistance

    Science.gov (United States)

    Bachalo, William D.; Inenaga, Andrew; Schuler, Carlos A.

    1995-12-01

    Aerometrics is developing an innovative laser-diode based device that provides a warning signal when a motor-vehicle deviates from the center of the lane. The device is based on a sensor that scans the roadway on either side of the vehicle and determines the lateral position relative to the existing painted lines marking the lane. No additional markings are required. A warning is used to alert the driver of excessive weaving or unanticipated departure from the center of the lane. The laser beams are at invisible wavelengths to that operation of the device does not pose a distraction to the driver or other motorists: When appropriate markers are not present on the road, the device is capable of detecting this condition and warn the driver. The sensor system is expected to work well irrespective of ambient light levels, fog and rain. This sensor has enormous commercial potential. It could be marketed as an instrument to warn drivers that they are weaving, used as a research tool to monitor driving patterns, be required equipment for those previously convicted of driving under the influence, or used as a backup sensor for vehicle lateral position control. It can also be used in storage plants to guide robotic delivery vehicles. In this paper, the principles of operation of the sensor, and the results of Aerometrics ongoing testing will be presented.

  16. Splenectomy revised: manually assisted splenectomy with the dexterity device--a feasibility study in 22 patients

    NARCIS (Netherlands)

    Meijer, D. W.; Gossot, D.; Jakimowicz, J. J.; de Wit, L. T.; Bannenberg, J. J.; Gouma, D. J.

    1999-01-01

    Laparoscopic splenectomy claims a number of advantages over open surgery: less trauma, quicker recovery, and faster return to normal activity. On the other hand, laparoscopic splenectomy is complex and time consuming, and so far, many surgeons are reluctant to perform such an operation. A new device

  17. What Are Some Types of Assistive Devices and How Are They Used?

    Science.gov (United States)

    ... make it possible for a child with limited motor skills to play with toys and games. Many types of devices help people with disabilities perform such ... people with impaired mobility or other disabilities drive motor vehicles . ... of rehabilitative technologies and their use » Related A- ...

  18. Chemometrics-assisted microfluidic paper-based analytical device for the determination of uric acid by silver nanoparticle plasmon resonance.

    Science.gov (United States)

    Hamedpour, Vahid; Postma, Geert J; van den Heuvel, Edwin; Jansen, Jeroen J; Suzuki, Koji; Citterio, Daniel

    2018-03-01

    This manuscript reports on the application of chemometric methods for the development of an optimized microfluidic paper-based analytical device (μPAD). As an example, we applied chemometric methods for both device optimization and data processing of results of a colorimetric uric acid assay. Box-Behnken designs (BBD) were utilized for the optimization of the device geometry and the amount of thermal inkjet-deposited assay reagents, which affect the assay performance. Measurement outliers were detected in real time by partial least squares discriminant analysis (PLS-DA) of scanned images. The colorimetric assay mechanism is based on the on-device formation of silver nanoparticles (AgNPs) through the interaction of uric acid, ammonia, and poly(vinyl alcohol) with silver ions under mild basic conditions. The yellow color originating from visible light absorption by localized surface plasmon resonance of AgNPs can be detected by the naked eye or, more quantitatively, with a simple flat-bed scanner. Under optimized conditions, the linearity of the calibration curve ranges from 0.1-5 × 10 -3 mol L -1 of uric acid with a limit of detection of 33.9 × 10 -6 mol L -1 and a relative standard of deviation 4.5% (n = 3 for determination of 5.0 × 10 -3 mol L -1 uric acid). Graphical abstract A chemometrics-assisted microfluidic paper-based analytical device was developed as a low-cost and rapid platform for the determination of uric acid (UA). The detection method is based on the chemical interaction of UA, ammonia, and polyvinyl alcohol under mild basic condition with silver ions inducing formation of yellow silver nanoparticles (AgNPs).

  19. Biventricular pacing-induced acute response in baroreflex sensitivity has predictive value for midterm response to cardiac resynchronization therapy

    NARCIS (Netherlands)

    Gademan, Maaike G. J.; van Bommel, Rutger J.; Borleffs, C. Jan Willem; Man, Sumche; Haest, Joris C. W.; Schalij, Martin J.; van der Wall, Ernst E.; Bax, Jeroen J.; Swenne, Cees A.

    2009-01-01

    In a previous study we demonstrated that the institution of biventricular pacing in chronic heart failure (CHF) acutely facilitates the arterial baroreflex. The arterial baroreflex has important prognostic value in CHF. We hypothesized that the acute response in baroreflex sensitivity (BRS) after

  20. Successful one stage biventricular correction of aortic atresia with a ventricular septal defect and discordant ventriculo-arterial connections

    NARCIS (Netherlands)

    Ebels, T; Dapper, F; Bohle, RM; Hagel, KJ; Nikkels, PGJ; Hehrlein, FW

    1997-01-01

    Aortic atresia is rare in the setting of a normally developed left ventricle with a ventricular septal defect. In this combination, as far as we know, it has been described only with concordant ventriculo-arterial connections, for which seven one-stage biventricular repairs have now been described.

  1. Vapor cycle energy system for implantable circulatory assist devices. Annual progress report Jul 1974--Jun 1975

    International Nuclear Information System (INIS)

    Hagen, K.G.

    1975-06-01

    The report describes the development status of a heart assist system driven by a nuclear fueled, electronically controlled vapor cycle engine termed the tidal regenerator engine (TRE). The TRE pressurization (typically from 5-160 psia) is controlled by a torque motor coupled to a displacer. The electrical power for the sensor, electronic logic and actuator is provided by a thermoelectric module interposed between the engine superheater and boiler. The TRE is direct coupled to an assist blood pump which also acts as a blood-cooled heat exchanger, pressure-volume transformer and sensor for the electronic logic. Engine efficiencies in excess of 14% have been demonstrated. Efficiency values as high as 13% have been achieved to date

  2. Vapor cycle energy system for implantable circulatory assist devices. Final summary May--Oct 1976

    International Nuclear Information System (INIS)

    Watelet, R.P.; Ruggles, A.E.; Hagen, K.G.

    1977-03-01

    The report describes the development status of a heart assist system driven by a nuclear-fueled, electronically controlled vapor cycle engine termed the tidal regenerator engine (TRE). The TRE pressurization is controlled by a torque motor coupled to a displacer. The electrical power for the sensor, electronic logic and actuator is provided by thermoelectric modules interposed between the engine superheater and boiler. The TRE is direct-coupled to an assist blood pump which also acts as a blood-cooled heat exchanger, pressure-volume trasformer and sensor for the electronic logic. Engine cycle efficiency in excess of 14% has been demonstrated routinely. Overall system efficiency on 33 watts of over 9% has been demonstrated (implied 13% engine cycle efficiency). A binary version of this engine in the annular configuration is now being tested. The preliminary tests demonstrated 10% cycle efficiency on the first buildup which ran well and started easily

  3. Numerical design and experimental hydraulic testing of an axial flow ventricular assist device for infants and children.

    Science.gov (United States)

    Throckmorton, Amy L; Untaroiu, Alexandrina; Allaire, Paul E; Wood, Houston G; Lim, D Scott; McCulloch, Michael A; Olsen, Don B

    2007-01-01

    Mechanical circulatory support options for infants and children are very limited in the United States. Existing circulatory support systems have proven successful for short-term pediatric assist, but are not completely successful as a bridge-to-transplant or bridge-to-recovery. To address this substantial need for alternative pediatric mechanical assist, we are developing a novel, magnetically levitated, axial flow pediatric ventricular assist device (PVAD) intended for longer-term ventricular support. Three major numerical design and optimization phases have been completed. A prototype was built based on the latest numerical design (PVAD3) and hydraulically tested in a flow loop. The plastic PVAD prototype delivered 0.5-4 lpm, generating pressure rises of 50-115 mm Hg for operating speeds of 6,000-9,000 rpm. The experimental testing data and the numerical predictions correlated well. The error between these sets of data was found to be generally 7.8% with a maximum deviation of 24% at higher flow rates. The axial fluid forces for the numerical simulations ranged from 0.5 to 1 N and deviated from the experimental results by generally 8.5% with a maximum deviation of 12% at higher flow rates. These hydraulic results demonstrate the excellent performance of the PVAD3 and illustrate the achievement of the design objectives.

  4. Design and Implementation of NTU Wearable Exoskeleton as an Enhancement and Assistive Device

    OpenAIRE

    Low, K. H.; Liu, X.; Yu, H.

    2006-01-01

    This article presents a wearable lower extremity exoskeleton (LEE) developed to enhance the ability of a human’s walking while carrying heavy loads. The ultimate goal of the current research work is to design and control a power assist system that integrates a human’s intellect for feedback and sensory purposes. The exoskeleton system in this work consists of an inner exoskeleton and an outer exoskeleton. The inner exoskeleton measures the movements of the wearer and provides these measuremen...

  5. Essential elements for assessment of persons with severe neurological impairments for computer access utilizing assistive technology devices: a Delphi study.

    Science.gov (United States)

    Hoppestad, Brian Scott

    2006-01-01

    The objective of this study was to determine prospective elements that should comprise a comprehensive and valid assessment of persons with severe disabilities for access to computers utilizing assistive technology (AT). Currently, there is a lack of guidelines regarding areas that permit a satisfactory measure of a person's need for AT devices to enable computer access, resulting in substandard services. A list of criteria for elements that should be incorporated into an instrument for determining AT for computer access was compiled from a literature review in the areas of neuroscience, rehabilitation, and education; and a Delphi study using an electronic survey form that was e-mailed to a panel of experts in the field of AT. Only those areas rated as essential to the assessment process ('very important' or 'important' by 80% of the respondents) were chosen as important criteria for an assessment instrument. The initial Delphi survey contained 22 categories (54 subcategories or elements) for incorporation into an assessment for computer access. The second round of the survey completed the Delphi process resulting in a consensus for inclusion of 39 of the elements in an assessment instrument. There are inherent obstacles to prescribing the proper AT device to assist disabled persons with computer access due to the complexity of his/her condition, and the multitude of technological devices available to aid persons in accomplishing diverse tasks. This study reveals the intricacy of the assessment process, especially in persons with severe disabilities associated with neurological conditions. An assessment instrument should be broad ranging, integrating both intrinsic and extrinsic factors, considering the multidimensional nature of AT prescription for computer access.

  6. Minimally Invasive Implantation of HeartWare Assist Device and Simultaneous Tricuspid Valve Reconstruction Through Partial Upper Sternotomy.

    Science.gov (United States)

    Hillebrand, Julia; Hoffmeier, Andreas; Djie Tiong Tjan, Tonny; Sindermann, Juergen R; Schmidt, Christoph; Martens, Sven; Scherer, Mirela

    2017-05-01

    Left ventricular assist device (LVAD) implantation is a well-established therapy to support patients with end-stage heart failure. However, the operative procedure is associated with severe trauma. Third generation LVADs like the HeartWare assist device (HeartWare, Inc., Framingham, MA, USA) are characterized by enhanced technology despite smaller size. These devices offer new minimally invasive surgical options. Tricuspid regurgitation requiring valve repair is frequent in patients with the need for mechanical circulatory support as it is strongly associated with ischemic and nonischemic cardiomyopathy. We report on HeartWare LVAD implantation and simultaneous tricuspid valve reconstruction through minimally invasive access by partial upper sternotomy to the fifth left intercostal space. Four male patients (mean age 51.72 ± 11.95 years) suffering from chronic heart failure due to dilative (three patients) and ischemic (one patient) cardiomyopathy and also exhibiting concomitant tricuspid valve insufficiency due to annular dilation underwent VAD implantation and tricuspid valve annuloplasty. Extracorporeal circulation was established via the ascending aorta, superior vena cava, and right atrium. In all four cases the LVAD implantation and tricuspid valve repair via partial median sternotomy was successful. During the operative procedure, no conversion to full sternotomy was necessary. One patient needed postoperative re-exploration because of pericardial effusion. No postoperative focal neurologic injury was observed. New generation VADs are advantageous because of the possibility of minimally invasive implantation procedure which can therefore minimize surgical trauma. Concomitant tricuspid valve reconstruction can also be performed simultaneously through partial upper sternotomy. Nevertheless, minimally invasive LVAD implantation is a challenging operative technique. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals

  7. Impact of aortic valve closure on adverse events and outcomes with the HeartWare ventricular assist device.

    Science.gov (United States)

    Dobarro, David; Urban, Marian; Booth, Karen; Wrightson, Neil; Castrodeza, Javier; Jungschleger, Jerome; Robinson-Smith, Nicola; Woods, Andrew; Parry, Gareth; Schueler, Stephan; MacGowan, Guy A

    2017-01-01

    This study examined whether aortic valve opening (AVO) and other echocardiographic parameters influence outcomes in patients on left ventricular (LV) assist device (LVAD) support. Pump thrombosis (PT) and ischemic stroke (IS) are known complications of LVAD, but mechanisms that could influence them are not completely understood. This was a retrospective analysis of 147 patients who received a HeartWare Ventricular Assist Device ( HeartWare International) as a bridge to transplant or to candidacy between July 2009 and August 2015, of whom 126 had at least 30 days of follow-up before the first event (30-days-out cohort). Outcomes included survival, PT, IS, and PT+IS (combined thrombotic event; CTE). Median time on support was 518 days. Of the 30-days-out cohort, 29% had a first PT and 19% a first IS. AVO was associated with longer survival on device (1,081 vs 723 days; p = 0.01) in the entire cohort. In the 30-days-out cohort, the aortic valve was more frequently closed in patients with lower ejection fractions on support (14% ± 6% vs 18% ± 9%; p = 0.009), more dilated pre-event echocardiogram (LV end-diastolic diameter, 66 ± 12 mm vs 62 ± 10 mm; p = 0.04), and pre-implant LV end-diastolic diameter (70 ± 10 mm vs 66 ± 9 mm; p = 0.06). CTE-free survival on the device was lower with a closed aortic valve (897 vs 1,314 days; p = 0.003) as was PT-free survival on the device (1,070 vs 1,457 days; p = 0.02). Cox regression analysis showed that AVO was an independent predictor of CTE (p = 0.03) CONCLUSIONS: Thrombotic events are relatively frequent in patients on long-term LVAD support. A closed aortic valve was associated with decreased overall survival, thrombosis-free survival, and poorer LV function on support. These are high-risk patients, so whether they require more intense anti-coagulation or prioritizing for transplantation requires further research. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All

  8. Functional hearing in the classroom: assistive listening devices for students with hearing impairment in a mainstream school setting.

    Science.gov (United States)

    Zanin, Julien; Rance, Gary

    2016-12-01

    To assess the benefit of assistive listening devices (ALDs) for students with hearing impairment in mainstream schools. Speech recognition (CNC words) in background noise was assessed in a typical classroom. Participants underwent testing using four device configurations: (1) HA(s)/CI(s) alone, (2) soundfield amplification, (3) remote microphone (Roger Pen) on desk and (4) remote microphone at the loudspeaker. A sub-group of students subsequently underwent a 2-week classroom trial of each ALD. Degree of improvement from baseline [HA(s)/CI(s)] alone was assessed using teacher and student Listening Inventory for Education-Revised (LIFE-R) questionnaires. In all, 20 students, aged 12.5-18.9 years, underwent speech recognition assessment. In total, 10 of these participated in the classroom trial. Hearing loss ranged from mild-to-profound levels. Performance in each ALD configuration was higher than for HAs/CIs alone (p  0.05). Speech recognition improvements were demonstrated with the implementation of both remote microphones and soundfield systems. Both students and teachers reported functional hearing advantages in the classroom when using the remote microphone in concert with their standard hearing devices.

  9. Development and validation of a computational fluid dynamics methodology for simulation of pulsatile left ventricular assist devices.

    Science.gov (United States)

    Medvitz, Richard B; Kreider, James W; Manning, Keefe B; Fontaine, Arnold A; Deutsch, Steven; Paterson, Eric G

    2007-01-01

    An unsteady computational fluid dynamic methodology was developed so that design analyses could be undertaken for devices such as the 50cc Penn State positive-displacement left ventricular assist device (LVAD). The piston motion observed in vitro was modeled, yielding the physiologic flow waveform observed during pulsatile experiments. Valve closure was modeled numerically by locally increasing fluid viscosity during the closed phase. Computational geometry contained Bjork-Shiley Monostrut mechanical heart valves in mitral and aortic positions. Cases for computational analysis included LVAD operation under steady-flow and pulsatile-flow conditions. Computations were validated by comparing simulation results with previously obtained in vitro particle image velocimetry (PIV) measurements. The steady portion of the analysis studied effects of mitral valve orientation, comparing the computational results with in vitro data obtained from mock circulatory loop experiments. The velocity field showed good qualitative agreement with the in vitro PIV data. The pulsatile flow simulations modeled the unsteady flow phenomena associated with a positive-displacement LVAD operating through several beat cycles. Flow velocity gradients allowed computation of the scalar wall strain rate, an important factor for determining hemodynamics of the device. Velocity magnitude contours compared well with PIV data throughout the cycle. Computational wall shear rates over the pulsatile cycle were found to be in the same range as wall shear rates observed in vitro.

  10. Trends in the Management of Patients With Left Ventricular Assist Devices Presenting for Noncardiac Surgery: A 10-Year Institutional Experience.

    Science.gov (United States)

    Stone, Marc; Hinchey, Joseph; Sattler, Christopher; Evans, Adam

    2016-09-01

    In our institution, the vast majority of patients presenting for noncardiac surgery (NCS) while supported by a left ventricular assist device (LVAD) are now cared for by noncardiac-trained anesthesiologists as the result of a decade of educational intervention to effect this transition. This represents a significant departure from the published experiences of other institutions. With institutional review board approval, we queried the database of our anesthesia record keeping system (CompuRecord) to determine various aspects of the perioperative management of these patients from July 1, 2003, through June 30, 2013, during which time 271 NCS procedures were performed on adult patients supported by LVADs. Over the entire study period (2003-2013), anesthetic care was provided by a cardiac anesthesiologist 47% of the time and by a noncardiac anesthesiologist 53% of the time. However, by the time period 2012-2013, 88% of the NCS procedures were staffed by a noncardiac anesthesiologist. Despite the prevalence of continuous flow devices in this series, the use of invasive blood pressure monitoring decreased dramatically by the later years of the study. Vasoactive and inotropic medications were rarely required intraoperatively. No intraoperative cardiac arrests, thromboembolic complications, or device malfunctions occurred. Our conclusion is that NCS procedures on LVAD-supported patients can be safely managed by educated noncardiac anesthesiologists. © The Author(s) 2015.

  11. Management of left ventricular assist devices after surgery: bridge, destination, and recovery.

    Science.gov (United States)

    Mountis, Maria M; Starling, Randall C

    2009-05-01

    As the use and understanding of mechanical circulatory support (MCS) increases, the management of these devices has become more conventional. The purpose of this review is to discuss the perioperative and long-term management of MCS patients. With the advent of axial flow pumps, both perioperative and long-term management are more standardized. The issues of nutrition, physical therapy, drive line care, and readiness to transition to home are becoming more mainstream and are readily accepted into the community. However, many factors remain that are not well defined in dealing with anticoagulation, weaning of MCS, achieving optimal device settings, and end-of-life care. Care for the MCS patient provided in a multidisciplinary team approach is imperative to allow for a seamless transition from the hospital and into the community and successful long-term outcomes.

  12. New Innovations in Circulatory Support With Ventricular Assist Device and Extracorporeal Membrane Oxygenation Therapy.

    Science.gov (United States)

    Sladen, Robert N

    2017-04-01

    The past decade has seen an exponential increase in the application and development of durable long-term as well as nondurable short-term mechanical circulatory support for cardiogenic shock and acute or chronic heart failure. Support has evolved from bridge-to-transplant to destination therapy, bridge to rescue, bridge to decision making, and bridge to a bridge. Notable trends include device miniaturization, minimally invasive and/or percutaneous insertion, and efforts to superimpose pulsatility on continuous flow. We can certainly anticipate that innovation will accelerate in the months and years to come. However, despite-or perhaps because of-the enhanced equipment now available, mechanical circulatory support is an expensive, complex, resource-intensive modality. It requires considerable expertise that should preferably be centralized to highly specialized centers. Formidable challenges remain: systemic inflammatory response syndromes and vasoplegia after device insertion; postoperative sepsis; optimal anticoagulation regimens to prevent device-induced thrombosis and cerebral thromboembolism; wound site, intracranial, and gastrointestinal bleeding; multisystem injury and failure; patient dissatisfaction (even when providers consider the procedure a "success"); and ethical decision making in conditions of futility.

  13. Risk assessment and comparative effectiveness of left ventricular assist device and medical management in ambulatory heart failure patients: design and rationale of the ROADMAP clinical trial.

    Science.gov (United States)

    Rogers, Joseph G; Boyle, Andrew J; O'Connell, John B; Horstmanshof, Douglas A; Haas, Donald C; Slaughter, Mark S; Park, Soon J; Farrar, David J; Starling, Randall C

    2015-02-01

    Mechanical circulatory support is now a proven therapy for the treatment of patients with advanced heart failure and cardiogenic shock. The role for this therapy in patients with less severe heart failure is unknown. The objective of this study is to examine the impact of mechanically assisted circulation using the HeartMate II left ventricular assist device in patients who meet current US Food and Drug Administration-defined criteria for treatment but are not yet receiving intravenous inotropic therapy. This is a prospective, nonrandomized clinical trial of 200 patients treated with either optimal medical management or a mechanical circulatory support device. This trial will be the first prospective clinical evaluation comparing outcomes of patients with advanced ambulatory heart failure treated with either ongoing medical therapy or a left ventricular assist device. It is anticipated to provide novel insights regarding relative outcomes with each treatment and an understanding of patient and provider acceptance of the ventricular assist device therapy. This trial will also provide information regarding the risk of events in "stable" patients with advanced heart failure and guidance for the optimal timing of left ventricular assist device therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. The use of mobile devices as assistive technology in resource-limited environments: access for learners with visual impairments in Kenya.

    Science.gov (United States)

    Foley, Alan R; Masingila, Joanna O

    2015-07-01

    In this paper, the authors explore the use of mobile devices as assistive technology for students with visual impairments in resource-limited environments. This paper provides initial data and analysis from an ongoing project in Kenya using tablet devices to provide access to education and independence for university students with visual impairments in Kenya. The project is a design-based research project in which we have developed and are refining a theoretically grounded intervention--a model for developing communities of practice to support the use of mobile technology as an assistive technology. We are collecting data to assess the efficacy and improve the model as well as inform the literature that has guided the design of the intervention. In examining the impact of the use of mobile devices for the students with visual impairments, we found that the devices provide the students with (a) access to education, (b) the means to participate in everyday life and (c) the opportunity to create a community of practice. Findings from this project suggest that communities of practice are both a viable and a valuable approach for facilitating the diffusion and support of mobile devices as assistive technology for students with visual impairments in resource-limited environments. Implications for Rehabilitation The use of mobile devices as assistive technology in resource-limited environments provides students with visual impairments access to education and enhanced means to participate in everyday life. Communities of practice are both a viable and a valuable approach for facilitating the diffusion and support of mobile devices as assistive technology for students with visual impairments in resource-limited environments. Providing access to assistive technology early and consistently throughout students' schooling builds both their skill and confidence and also demonstrates the capabilities of people with visual impairments to the larger society.

  15. SdrF, a Staphylococcus epidermidis surface protein, contributes to the initiation of ventricular assist device driveline-related infections.

    Directory of Open Access Journals (Sweden)

    Carlos Arrecubieta

    2009-05-01

    Full Text Available Staphylococcus epidermidis remains the predominant pathogen in prosthetic-device infections. Ventricular assist devices, a recently developed form of therapy for end-stage congestive heart failure, have had considerable success. However, infections, most often caused by Staphylococcus epidermidis, have limited their long-term use. The transcutaneous driveline entry site acts as a potential portal of entry for bacteria, allowing development of either localized or systemic infections. A novel in vitro binding assay using explanted drivelines obtained from patients undergoing transplantation and a heterologous lactococcal system of surface protein expression were used to identify S. epidermidis surface components involved in the pathogenesis of driveline infections. Of the four components tested, SdrF, SdrG, PIA, and GehD, SdrF was identified as the primary ligand. SdrF adherence was mediated via its B domain attaching to host collagen deposited on the surface of the driveline. Antibodies directed against SdrF reduced adherence of S. epidermidis to the drivelines. SdrF was also found to adhere with high affinity to Dacron, the hydrophobic polymeric outer surface of drivelines. Solid phase binding assays showed that SdrF was also able to adhere to other hydrophobic artificial materials such as polystyrene. A murine model of infection was developed and used to test the role of SdrF during in vivo driveline infection. SdrF alone was able to mediate bacterial adherence to implanted drivelines. Anti-SdrF antibodies reduced S. epidermidis colonization of implanted drivelines. SdrF appears to play a key role in the initiation of ventricular assist device driveline infections caused by S. epidermidis. This pluripotential adherence capacity provides a potential pathway to infection with SdrF-positive commensal staphylococci first adhering to the external Dacron-coated driveline at the transcutaneous entry site, then spreading along the collagen

  16. Benefit of warm water immersion on biventricular function in patients with chronic heart failure

    Directory of Open Access Journals (Sweden)

    Kardassis Dimitris

    2009-07-01

    Full Text Available Abstract Background Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety. The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP. Methods Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, peakVO2 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C. Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly. Results During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy. Conclusion Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

  17. Wearable Monitoring Devices for Assistive Technology: Case Studies in Post-Polio Syndrome

    Directory of Open Access Journals (Sweden)

    Giuseppe Andreoni

    2014-01-01

    Full Text Available The correct choice and customization of an orthosis are crucial to obtain the best comfort and efficiency. This study explored the feasibility of a multivariate quantitative assessment of the functional efficiency of lower limb orthosis through a novel wearable system. Gait basographic parameters and energetic indexes were analysed during a Six-Minute Walking Test (6-MWT through a cost-effective, non-invasive polygraph device, with a multichannel wireless transmission, that carried out electro-cardiograph (ECG; impedance-cardiograph (ICG; and lower-limb accelerations detection. Four subjects affected by Post-Polio Syndrome (PPS were recruited. The wearable device and the semi-automatic post-processing software provided a novel set of objective data to assess the overall efficiency of the patient-orthosis system. Despite the small number of examined subjects, the results obtained with this new approach encourage the application of the method thus enlarging the dataset to validate this promising protocol and measuring system in supporting clinical decisions and out of a laboratory environment.

  18. Exploring bubble oscillation and mass transfer enhancement in acoustic-assisted liquid-liquid extraction with a microfluidic device

    Science.gov (United States)

    Xie, Yuliang; Chindam, Chandraprakash; Nama, Nitesh; Yang, Shikuan; Lu, Mengqian; Zhao, Yanhui; Mai, John D.; Costanzo, Francesco; Huang, Tony Jun

    2015-01-01

    We investigated bubble oscillation and its induced enhancement of mass transfer in a liquid-liquid extraction process with an acoustically-driven, bubble-based microfluidic device. The oscillation of individually trapped bubbles, of known sizes, in microchannels was studied at both a fixed frequency, and over a range of frequencies. Resonant frequencies were analytically identified and were found to be in agreement with the experimental observations. The acoustic streaming induced by the bubble oscillation was identified as the cause of this enhanced extraction. Experiments extracting Rhodanmine B from an aqueous phase (DI water) to an organic phase (1-octanol) were performed to determine the relationship between extraction efficiency and applied acoustic power. The enhanced efficiency in mass transport via these acoustic-energy-assisted processes was confirmed by comparisons against a pure diffusion-based process. PMID:26223474

  19. Neurohormonal activation and exercise tolerance in patients supported with a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Jung, Mette Holme; Goetze, Jens Peter; Boesgaard, Soeren

    2016-01-01

    BACKGROUND: Neurohormones play a key role in regulating hemodynamics in heart failure (HF) both at rest and during exercise. In contrast, little is known about the importance of neurohormonal regulation for exercise capacity in continuous-flow left ventricular assist device (CF-LVAD) patients....... The aim of this study was to assess the relation between neurohormonal activation patterns in CF-LVAD patients and exercise capacity. METHODS: Plasma concentrations of the C-terminal portion of pro-arginine vasopressin precursor (copeptin), pro-adrenomedullin (proADM), pro-B-type (proBNP) and pro......-atrial (proANP) natriuretic peptides were measured in 25 CF-LVAD patients (HeartMate II) in the morning prior to maximal cardiopulmonary exercise testing determining peak oxygen uptake (peak VO2). Quality of life (QOL) was determined by questionnaires. RESULTS: Peak VO2 was severely reduced averaging 13...

  20. Predictors of changes in health status between and within patients 12 months post left ventricular assist device implantation

    DEFF Research Database (Denmark)

    Brouwers, Corline; de Jonge, Nicolaas; Caliskan, Kadir

    2014-01-01

    LVAD implantation. METHODS: Health status [Kansas City Cardiomyopathy Questionnaire (KCCQ); Short-Form 12 (SF-12)] were assessed at 3-4 weeks after implantation, and at 3, 6 and 12 months follow up in 54 LVAD patients (74% men; mean age 54 ± 9 years). RESULTS: Patients experienced significant...... improvements in health status between baseline and 3 months follow-up as assessed by the KCCQ (clinical summary score: F = 33.49, P mental component score: F = 21.77, P ...BACKGROUND: Improving patient-reported outcomes (e.g. health status) has become an important goal in left ventricular assist device (LVAD) therapy, in addition to reducing mortality and morbidity. We examined predictors of changes in health status scores between and within patients 12 months post...

  1. Vacuum-assisted closure device: a useful tool in the management of severe intrathoracic infections.

    Science.gov (United States)

    Saadi, Alend; Perentes, Jean Yannis; Gonzalez, Michel; Tempia, Adrien Caliera; Wang, Yabo; Demartines, Nicolas; Ris, Hans-Beat; Krueger, Thorsten

    2011-05-01

    This study is an evaluation of the vacuum-assisted closure (VAC) therapy for the treatment of severe intrathoracic infections complicating lung resection, esophageal surgery, viscera perforation, or necrotizing pleuropulmonary infections. We reviewed the medical records of all patients treated by intrathoracic VAC therapy between January 2005 and December 2008. All patients underwent surgical debridement-decortication and control of the underlying cause of infection such as treatment of bronchus stump insufficiency, resection of necrotic lung, or closure of esophageal or intestinal leaks. Surgery was followed by intrathoracic VAC therapy until the infection was controlled. The VAC dressings were changed under general anesthesia and the chest wall was temporarily closed after each dressing change. All patients received systemic antibiotic therapy. Twenty-seven patients (15 male, median age 64 years) underwent intrathoracic VAC dressings for the management of postresectional empyema (n=8) with and without bronchopleural fistula, necrotizing infections (n=7), and intrathoracic gastrointestinal leaks (n=12). The median length of VAC therapy was 22 days (range 5 to 66) and the median number of VAC changes per patient was 6 (range 2 to 16). In-hospital mortality was 19% (n=5) and was not related to VAC therapy or intrathoracic infection. Control of intrathoracic infection and closure of the chest cavity was achieved in all surviving patients. Vacuum-assisted closure therapy is an efficient and safe adjunct to treat severe intrathoracic infections and may be a good alternative to the open window thoracostomy in selected patients. Long time intervals in between VAC changes and short course of therapy result in good patient acceptance. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Reevaluation of the Harboe assay as a standardized method of assessment for the hemolytic performance of ventricular assist devices.

    Science.gov (United States)

    Chan, Chris H H; Hilton, Andrew; Foster, Graham; Hawkins, Karl

    2012-08-01

    The Harboe spectrophotometric assay is regarded as one of the safest and most reproducible methods for measuring plasma free hemoglobin (pfHb). However, there is still some ambiguity in the application of the assay when assessing the hemolytic performance of ventricular assist devices (VADs). The purpose of this study was to reexamine and compare values of pfHb obtained using different concentrations of plasma diluent (Na(2) CO(3) ) as cited by various studies such that a standard practice may be recommended for the application of the Harboe assay in the hemolytic evaluation of VADs, allowing reliable comparisons to be made between laboratories. As a means to examine the Harboe assay, a BioMedicus BPX-80 was tested using both whole blood and a washed suspension of red blood cells (RBCs). Results show that for whole blood, the pfHb may be underestimated by 13-23%, dependent upon the concentration of Na(2) CO(3) diluent solution. This trend was not observed for the washed suspension of RBCs. Furthermore, it is shown that the concentration of diluent influences the stability of a sample. The results of this study show that the problems associated with the incongruity of pfHb readings are a direct result of the precipitation of proteins from the plasma under alkaline conditions; as the molarity of the diluent controls pH, it becomes essential to use the appropriate concentration of Na(2) CO(3) diluent in order to avoid turbidity of the solution and the consequent misrepresentation of pfHb values. Such standardization is pertinent when measuring the very low levels of pfHb observed during the in vivo testing of modern ventricular assist devices. © 2012, Copyright the Authors. Artificial Organs © 2012, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  3. Response of a physiological controller for ventricular assist devices during acute patho-physiological events: an in vitro study.

    Science.gov (United States)

    Petrou, Anastasios; Pergantis, Panagiotis; Ochsner, Gregor; Amacher, Raffael; Krabatsch, Thomas; Falk, Volkmar; Meboldt, Mirko; Daners, Marianne Schmid

    2017-11-27

    The current paper analyzes the performance of a physiological controller for turbodynamic ventricular assist devices (tVADs) during acute patho-physiological events. The numerical model of the human blood circulation implemented on our hybrid mock circulation was extended in order to simulate the Valsalva maneuver (VM) and premature ventricular contractions (PVCs). The performance of an end-diastolic volume (EDV)-based physiological controller for VADs, named preload responsive speed (PRS) controller was evaluated under VM and PVCs. A slow and a fast response of the PRS controller were implemented by using a 3 s moving window, and a beat-to-beat method, respectively, to extract the EDV index. The hemodynamics of a pathological circulation, assisted by a tVAD controlled by the PRS controller were analyzed and compared with a constant speed support case. The results show that the PRS controller prevented suction during the VM with both methods, while with constant speed, this was not the case. On the other hand, the pump flow reduction with the PRS controller led to low aortic pressure, while it remained physiological with the constant speed control. Pump backflow was increased when the moving window was used but it avoided sudden undesirable speed changes, which occurred during PVCs with the beat-to-beat method. In a possible clinical implementation of any physiological controller, the desired performance during frequent clinical acute scenarios should be considered.

  4. Interhospital air transport of a blind patient on extracorporeal life support with consecutive and successful left ventricular assist device implantation.

    Science.gov (United States)

    Bauer, Adrian; Schaarschmidt, Jan; Grosse, F Oliver; Al Alam, Nidal; Hausmann, Harald; Krämer, Klaus; Strüber, Martin; Mohr, Friedrich W

    2014-06-01

    The use of extracorporeal life support systems (ECLS) in patients with postcardiotomy low cardiac output syndrome (LCO) as a bridge to recovery and bridge to implantation of ventricular assist device (VAD) is common nowadays. A 59-year-old patient with acute myocardial infarction received a percutaneous transluminal angioplasty and stenting of the circumflex artery. During catheterization of the left coronary artery (LAD), the patient showed ventricular fibrillation and required defibrillation and cardiopulmonary resuscitation. After implantation of an intra-aortic balloon pump, the patient immediately was transmitted to the operating room. He received emergency coronary artery bypass grafting in a beating heart technique using pump-assisted minimal extracorporeal circulation circuit (MECC). Two bypass grafts were performed to the LAD and the right posterior descending artery. Despite initial successful weaning off cardiopulmonary bypass with high-dose inotropic support, the patient presented postcardiotomy LCO and an ECLS was implanted. The primary setup of the heparin-coated MECC system was modified and used postoperatively. As a result of the absence of an in-house VAD program, the patient was switched to a transportable ECLS the next day and was transferred by helicopter to the nearest VAD center where the patient received a successful insertion of a left VAD 3 days later.

  5. Central-Approach Surgical Repair of Coarctation of the Aorta with a Back-up Left Ventricular Assist Device for an Infant Presenting with Severe Left Ventricular Dysfunction

    Directory of Open Access Journals (Sweden)

    Tae Hoon Kim

    2015-12-01

    Full Text Available A two-month-old infant presented with coarctation of the aorta, severe left ventricular dysfunction, and moderate to severe mitral regurgitation. Through median sternotomy, the aortic arch was repaired under cardiopulmonary bypass and regional cerebral perfusion. The patient was postoperatively supported with a left ventricular assist device for five days. Left ventricular function gradually improved, eventually recovering with the concomitant regression of mitral regurgitation. Prompt surgical repair of coarctation of the aorta is indicated for patients with severe left ventricular dysfunction. A central approach for surgical repair with a back-up left ventricular assist device is a safe and effective treatment strategy for these patients.

  6. In vivo evaluation of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

    Science.gov (United States)

    Saeed, Diyar; Shalli, Shanaz; Fumoto, Hideyuki; Ootaki, Yoshio; Horai, Tetsuya; Anzai, Tomohiro; Zahr, Roula; Horvath, David J; Massiello, Alex L; Chen, Ji-Feng; Dessoffy, Raymond; Catanese, Jacquelyn; Benefit, Stephen; Golding, Leonard A R; Fukamachi, Kiyotaka

    2010-06-01

    Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14-91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.

  7. Design of a right ventricular mock circulation loop as a test bench for right ventricular assist devices.

    Science.gov (United States)

    Mueller, Indra; Jansen-Park, So-Hyun; Neidlin, Michael; Steinseifer, Ulrich; Abel, Dirk; Autschbach, Rüdiger; Rossaint, Rolf; Schmitz-Rode, Thomas; Sonntag, Simon Johannes

    2017-04-01

    Right heart failure (RHF), e.g. due to pulmonary hypertension (PH), is a serious health issue with growing occurrence and high mortality rate. Limited efficacy of medication in advanced stages of the disease constitutes the need for mechanical circulatory support of the right ventricle (RV). An essential contribution to the process of developing right ventricular assist devices (RVADs) is the in vitro test bench, which simulates the hemodynamic behavior of the native circulatory system. To model healthy and diseased arterial-pulmonary hemodynamics in adults (mild and severe PH and RHF), a right heart mock circulation loop (MCL) was developed. Incorporating an anatomically shaped silicone RV and a silicone atrium, it not only enables investigations of hemodynamic values but also suction events or the handling of minimal invasive RVADs in an anatomical test environment. Ventricular pressure-volume loops of all simulated conditions as well as pressure and volume waveforms were recorded and compared to literature data. In an exemplary test, an RVAD was connected to the apex to further test the feasibility of studying such devices with the developed MCL. In conclusion, the hemodynamic behavior of the native system was well reproduced by the developed MCL, which is a useful basis for future RVAD tests.

  8. Flow visualization of three-dimensionality inside the 12 cc Penn State pulsatile pediatric ventricular assist device.

    Science.gov (United States)

    Roszelle, Breigh N; Deutsch, Steven; Manning, Keefe B

    2010-02-01

    In order to aid the ongoing concern of limited organ availability for pediatric heart transplants, Penn State has continued development of a pulsatile Pediatric Ventricular Assist Device (PVAD). Initial studies of the PVAD observed an increase in thrombus formation due to differences in flow field physics when compared to adult sized devices, which included a higher degree of three-dimensionality. This unique flow field brings into question the use of 2D planar particle image velocimetry (PIV) as a flow visualization technique, however the small size and high curvature of the PVAD make other tools such as stereoscopic PIV impractical. In order to test the reliability of the 2D results, we perform a pseudo-3D PIV study using planes both parallel and normal to the diaphragm employing a mock circulatory loop containing a viscoelastic fluid that mimics 40% hematocrit blood. We find that while the third component of velocity is extremely helpful to a physical understanding of the flow, particularly of the diastolic jet and the development of a desired rotational pattern, the flow data taken parallel to the diaphragm is sufficient to describe the wall shear rates, a critical aspect to the study of thrombosis and design of such pumps.

  9. [Psychological evaluation and support in patients with left ventricular assist devices: preliminary data at 6-month follow-up].

    Science.gov (United States)

    Voltolini, Alessandra; Minotti, Anna; Verde, Alessandro; Cipriani, Manlio; Garascia, Andrea; Turazza, Fabio; Macera, Francesca; Perna, Enrico; Russo, Claudio F; Fumagalli, Emilia; Frigerio, Maria

    2016-11-01

    Heart disease has an impact on patient's identity and self-perception. Taking into account the wide literature about psychological aspects before and after heart transplant, it clearly emerges that there is a lack of data and results for patients up to implantation of ventricular assist devices (VAD). The aim of the present study was to explore quality of life and factors correlated with psychological adjustment in patients supported with VAD. From February 2013 to August 2014, 18 patients (17 male, mean age 57 years) under clinical evaluation before and after VAD implantation were enrolled. During interviews, patients were assessed with EuroQoL-5D questionnaire to monitor improvement of quality of life before implantation and at 3 and 6 months; critical issues, needs and point of views of patients have been described. A significant improvement in the quality of life score was observed at 3 (score 38 [interquartile range 30-40] vs 75 [60-80], ppsychological state investigated by the test showed a clear and positive trend. All patients need to empower through complete information about the device, related risks and life expectancy. Interdisciplinary approach improved compliance with therapy. Successful treatment and efficient psychological care are closely related to assessment and continuous clinical support. This approach ensures a better selection of patients and improves their compliance. Further data are needed to support our preliminary observations and to explore long-term quality of life.

  10. Failure Strain and Strain-Stress Analysis in Titanium Nitride Coatings Deposited on Religa Heart Ext Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Kopernik M.

    2015-04-01

    Full Text Available The Polish ventricular assist device is made of Bionate II with deposited TiN biocompatible nano-coating. The two scale finite element model is composed of a macro-model of blood chamber and a micro-model of the TiN/Bionate II. The numerical analysis of stress and strain states confirmed the possibility of fracture. Therefore, the identification of a fracture parameter considered as a failure strain is the purpose of the present work. The tensile test in a micro chamber of the SEM was performed to calibrate the fracture parameter of the material system TiN/Bionate II. The failure strain is a function of a temperature, a thickness of coating and parameters of surface's profile. The failure strain was calculated at the stage of the test, in which the initiation of fracture occurred. The finite element micro-model includes the surface roughness and the failure strain under tension condition for two thicknesses of coatings which will be deposited on the medical device.

  11. Use of Post-acute Care Services and Readmissions After Left Ventricular Assist Device Implantation in Privately Insured Patients.

    Science.gov (United States)

    Dunlay, Shannon M; Haas, Lindsey R; Herrin, Jeph; Schilz, Stephanie R; Stulak, John M; Kushwaha, Sudhir S; Shah, Nilay D

    2015-10-01

    Very little is known about health care resource utilization, including post-acute care use and hospital readmissions, after left ventricular assist device (LVAD) implantation. Administrative claims from a database of multiple United States health plans were used to identify patients that received an LVAD (ICD-9 code 37.66) and survived to hospital discharge from January 1-2006, through September 30-2013. Post-acute care use was defined as a skilled nursing facility or rehabilitation stay within 90 days after hospital discharge. Patients were censored at heart transplantation or end of coverage through December 31-2013. Of 583 patients (mean age 55 years, 77% male), 223 (38.3%) used post-acute care services, more commonly in patients with diabetes, who required hemodialysis, and who had LVADs implanted at hospitals in more populated areas, with more beds, and in the northeast region (P device complications, heart failure, and arrhythmia. Readmission risk was higher in patients who had diabetes, peripheral vascular disease, and longer hospital length of stay, but it did not differ by post-acute care use. Use of post-acute care services varies based on hospital characteristics. We found no association between post-acute care use and readmission risk after LVAD implantation. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device

    Science.gov (United States)

    Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

    2012-01-01

    The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

  13. Biventricular support using a centrifugal pump in a 6 year old with fulminant myocarditis.

    Science.gov (United States)

    Kehara, Hiromu; Takano, Tamaki; Terasaki, Takamitsu; Okada, Kenji

    2017-06-01

    We experienced a case of ventricular assist with both a pulsatile-flow and a continuous-flow pump in a pediatric patient, and herein report the clinical course and characteristics of the pumps. A 6-year-old female was diagnosed with fulminant myocarditis and transferred to our hospital for mechanical support. After 12 days of extracorporeal membrane oxygenation, we implanted a left ventricular assist device (LVAD) and a right ventricular assist device (RVAD) using centrifugal Gyro pumps with a membrane oxygenator in a paracorporeal fashion. The membrane oxygenator was removed on postoperative day (POD) 4, and the patient was weaned from the respirator on POD 6. The LVAD was exchanged on POD 13 and 17, and the RVAD was exchanged on POD 14 because of thrombus formation inside the pumps. The RVAD was removed on POD 25. On POD 32, the patient experienced cerebral infarction and the centrifugal Gyro pump was switched to an extracorporeal pulsatile pump. No thromboembolic event occurred after pump conversion, although continuous administration of vasodilators was required to avoid hypertension. She underwent successfully heart transplantation in the USA after 8 months of ventricular support. A centrifugal pump is considered useful for pediatric patients, as pump flow and blood pressure can be relatively easily controlled in the postoperative acute phase compared with the pulsatile pump. However, special care should be taken to monitor for thrombus formation when support length becomes longer than 13 days, and a switch to a pulsatile pump should be considered once the hemodynamic status stabilizes.

  14. Applying a soft-robotic glove as assistive device and training tool with games to support hand function after stroke: Preliminary results on feasibility and potential clinical impact.

    Science.gov (United States)

    Prange-Lasonder, Gerdienke B; Radder, Bob; Kottink, Anke I R; Melendez-Calderon, Alejandro; Buurke, Jaap H; Rietman, Johan S

    2017-07-01

    Recent technological developments regarding wearable soft-robotic devices extend beyond the current application of rehabilitation robotics and enable unobtrusive support of the arms and hands during daily activities. In this light, the HandinMind (HiM) system was developed, comprising a soft-robotic, grip supporting glove with an added computer gaming environment. The present study aims to gain first insight into the feasibility of clinical application of the HiM system and its potential impact. In order to do so, both the direct influence of the HiM system on hand function as assistive device and its therapeutic potential, of either assistive or therapeutic use, were explored. A pilot randomized clinical trial was combined with a cross-sectional measurement (comparing performance with and without glove) at baseline in 5 chronic stroke patients, to investigate both the direct assistive and potential therapeutic effects of the HiM system. Extended use of the soft-robotic glove as assistive device at home or with dedicated gaming exercises in a clinical setting was applicable and feasible. A positive assistive effect of the soft-robotic glove was proposed for pinch strength and functional task performance 'lifting full cans' in most of the five participants. A potential therapeutic impact was suggested with predominantly improved hand strength in both participants with assistive use, and faster functional task performance in both participants with therapeutic application.

  15. Development of chemically assisted etching method for GaAs-based optoelectronic devices

    International Nuclear Information System (INIS)

    Gaillard, M.; Rhallabi, A.; Elmonser, L.; Talneau, A.; Pommereau, F.; Pagnod-Rossiaux, Ph.; Bouadma, N.

    2005-01-01

    Chemically assisted ion beam etching of GaAs-based materials using Cl 2 reactive gas was has been experimentally and theoretically examined. The primary effort was the design of an etching system for high reproducibility and improved throughput. Characteristics of the etching process, i.e., etch rate, etch profiles, and surface morphology as a function of etching parameters, i.e., substrate temperature, Cl 2 flow rate, ion current density, and energy are reported. In addition, we have analyzed the etched surfaces qualitatively by Auger electron spectroscopy, and quantitatively by atomic force microscopy. The developed process yielded stoichiometric and smooth GaAs surfaces. Moreover, in order to understand the mechanism of the Cl 2 etching reaction with GaAs, a simulation of the etch profile evolution with time as function of etching parameters was carried out. Simulations were compared with experimentally derived data and were found to be in good agreement. Finally, the developed process was successfully applied to the fabrication of ridge waveguides GaAs/GaAlAs lasers with cw optical characteristics similar to wet chemical etched lasers

  16. Accelerated extraction of the fat content in cheese using a focused microwave-assisted soxhlet device.

    Science.gov (United States)

    García-Ayuso, L E; Velasco, J; Dobarganes, M C; Luque De Castro, M D

    1999-06-01

    A fast method for hydrolysis and extraction of fat in cheese based on the use of a Soxhlet extractor assisted by microwaves is proposed. The use of this type of energy dramatically reduces the time required for both steps (namely, the hydrolysis time was decreased from 1 h to 10 min with avoidance of the neutralization step, and the extraction time was decreased from 6 h to 40 min), providing similar efficiency and reproducibility comparable to or better than that of the conventional Soxhlet methodology. In addition, the proposed method is cleaner than conventional Soxhlet, as 80-85% of the extractant is recycled. The determination of the fatty acid composition by gas-liquid chromatography and quantification of both polymer formation by high-performance size exclusion liquid chromatography and nonpolar triacylglycerol formation by thin-layer chromatography with flame ionization detection in the extracts obtained by the proposed method, conventional Soxhlet and Weibull-Berntrop procedures (Soxhlet with a prior hydrolysis step), showed that the quality of the extracts obtained by the proposed procedure is better than that of the conventional alternatives, possibly due to the shorter time required by the accelerated method.

  17. Design and Implementation of NTU Wearable Exoskeleton as an Enhancement and Assistive Device

    Directory of Open Access Journals (Sweden)

    K. H. Low

    2006-01-01

    Full Text Available This article presents a wearable lower extremity exoskeleton (LEE developed to enhance the ability of a human’s walking while carrying heavy loads. The ultimate goal of the current research work is to design and control a power assist system that integrates a human’s intellect for feedback and sensory purposes. The exoskeleton system in this work consists of an inner exoskeleton and an outer exoskeleton. The inner exoskeleton measures the movements of the wearer and provides these measurements to the outer exoskeleton, which supports the whole exoskeleton system to walk following the wearer. A special footpad, which is designed and attached to the outer exoskeleton, can measure the zero moment point (ZMP of the human as well as that of the exoskeleton in time. Using the measured human ZMP as the reference, the exoskeleton’s ZMP is controlled by trunk compensation so that the exoskeleton can walk stably. A simulation platform has first been developed to examine the gait coordination through inner and outer exoskeletons. A commercially available software, xPC Target, together with other toolboxes from MATLAB, has then been used to provide a real-time operating system for controlling the exoskeleton. Real-time locomotion control of the exoskeleton is implemented in the developed environment. Finally, some experiments on different objects showed that the stable walking can be achieved in the real environment.

  18. In vitro hydrodynamic analysis of pin and cone bearing designs of the Jarvik 2000 adult ventricular assist device.

    Science.gov (United States)

    Stanfield, J Ryan; Selzman, Craig H

    2013-09-01

    The Jarvik 2000 adult ventricular assist device (VAD) is a second-generation blood pump with mechanical contact bearings. The original configuration of the pump employed a pin bearing and a more recent configuration uses a cone bearing. We compare the hydrodynamic performance of the two designs under steady-state and pulsatile flow conditions in vitro. Furthermore, we employ the Intermittent Low Speed (ILS) Flowmaker Controller to demonstrate the effect on pulsatility index (PI) performance of both device configurations. We use an open-loop flow system in both steady-state and pulsatile arrangements, complete with pressure transducers and flow probes. Working fluid was a 3.6 cP blood-analog, glycerin-water solution. Steady-state flow tests were carried out to determine pressure-flow (H-Q) performance curves. Pulsatile tests under normotensive, hypertensive, and hypotensive conditions were executed with controller speed 3 (10710 ± 250 rpm) at 100 beats per minute. Steady-state tests show greater capacity for pressure and flow with the cone bearing, compared with pin bearing, with best efficiency point (BEP) 68% greater for cone bearing. Pulsatile tests show the cone bearing design to yield a 20% increase in Qavg , a 17% decrease in pulsatility index (PIQ ), and a qualitative increase in pressure responsivity. The ILS mode (for both bearing designs) decreases Qavg by 68% and likewise increases PIQ by 360% and pulsatility ratio (Rpul ) by 200%. The ILS controller regularly reduces the flow, increasing pulsatility index during device operation. The Jarvik 2000 continuous-flow VAD can sustain pulsatile flow under pulsating pressure conditions. The new cone bearing design yields increased flow rates over the earlier pin bearing design. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  19. Ventricular Assist Device implant (AB 5000 prototype cannula: In vitro assessment of MRI issues at 3-Tesla

    Directory of Open Access Journals (Sweden)

    Valencerina Samuel

    2008-05-01

    Full Text Available Abstract Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD. Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged SAR of 3-W/kg for 15-min. Artifacts were assessed for the main metallic component of this VAD (atrial cannula using T1-weighted, spin echo and gradient echo pulse sequences. Results The AB5000 Ventricle with the prototype In-Flow Cannula and Out-Flow Cannula attached showed relatively minor magnetic field interactions that will not cause movement in situ. Heating was not excessive (highest temperature change, +0.8°C. Artifacts may create issues for diagnostic imaging if the area of interest is in the same area or close to the implanted metallic component of this VAD (i.e., the venous cannula. Conclusion The results of this investigation demonstrated that it would be acceptable for a patient with this VAD (AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached to undergo MRI at 3-Tesla or less. Notably, it is likely that the operation console for this device requires positioning a suitable distance (beyond the 100 Gauss line or in the MR control room from the 3-Tesla MR system to ensure proper function of the VAD.

  20. Intelligent speed adaptation as an assistive device for drivers with acquired brain injury: a single-case field experiment.

    Science.gov (United States)

    Klarborg, Brith; Lahrmann, Harry; NielsAgerholm; Tradisauskas, Nerius; Harms, Lisbeth

    2012-09-01

    Intelligent speed adaptation (ISA) was tested as an assistive device for drivers with an acquired brain injury (ABI). The study was part of the "Pay as You Speed" project (PAYS) and used the same equipment and technology as the main study (Lahrmann et al., in press-a, in press-b). Two drivers with ABI were recruited as subjects and had ISA equipment installed in their private vehicle. Their speed was logged with ISA equipment for a total of 30 weeks of which 12 weeks were with an active ISA user interface (6 weeks=Baseline 1; 12 weeks=ISA period; 12 weeks=Baseline 2). The subjects participated in two semi-structured interviews concerning their strategies for driving with ABI and for driving with ISA. Furthermore, they gave consent to have data from their clinical journals and be a part of the study. The two subjects did not report any instances of being distracted or confused by ISA, and in general they described driving with ISA as relaxed. ISA reduced the percentage of the total distance that was driven with a speed above the speed limit (PDA), but the subjects relapsed to their previous PDA level in Baseline 2. This suggests that ISA is more suited as a permanent assistive device (i.e. cognitive prosthesis) than as a temporary training device. As ABI is associated with a multitude of cognitive deficits, we developed a conceptual framework, which focused on the cognitive parameters that have been shown to relate to speeding behaviour, namely "intention to speed" and "inattention to speeding". The subjects' combined status on the two independent parameters made up their "speeding profile". A comparison of the speeding profiles and the speed logs indicated that ISA in the present study was more efficient in reducing inattention to speeding than affecting intention to speed. This finding suggests that ISA might be more suited for some neuropsychological profiles than for others, and that customisation of ISA for different neuropsychological profiles may be required

  1. Temporary Left Ventricular Assist Device Through an Axillary Access is a Promising Approach to Improve Outcomes in Refractory Cardiogenic Shock Patients

    OpenAIRE

    Doersch, Karen M.; Tong, Carl W.; Gongora, Enrique; Konda, Subbareddy; Sareyyupoglu, Basar

    2015-01-01

    Cardiogenic shock (CS) causes significant morbidity and mortality and such patients can deteriorate rapidly. Temporary left ventricular assist devices (LVADs) are a promising approach to manage these patients. The following is a case series in which patients stabilized with a temporary LVAD for CS improvement were analyzed retrospectively. Between June 2011 and January 2014, 15 patients received temporary devices through an axillary approach (mean age: 53 ± 15, 93% male). Mean survival time w...

  2. Characterization of Nanophosphors for Solid State Lighting Devices Grown by Microwave Plasma Assisted Deposition Process

    Science.gov (United States)

    McCoy, Jedidiah; Merlak, Marek; Witanachchi, Sarath

    2013-03-01

    Increasingly, greenhouse farming and urban agriculture are being looked at as a more efficient and more cost effective way to grow produce. Currently the lights used in greenhouses rely on light sources that emit a broad spectrum of light. However, only light at wavelengths around 460 nm (blue) and 670 nm (red) are absorbed by most plants for photosynthesis. Solid state lighting devices can be engineered to produce light to match the needs of the plant while reducing the energy cost. An investigation into the photoluminescence properties of the nanophosphor La2O3 doped with Bi was done in an effort to produce a phosphor emitting in blue wavelengths. The La2O3:Bi coatings were grown using a microwave plasma growth process. Microwave power and chamber pressure were varied to find the optimum synthesis conditions. Power was varied from 100Watts to 900Watts and chamber pressure was varied from 30Torr to 60Torr. The process utilized O2 and CO2 plasma. The nanophosphors were investigated by X-ray diffraction, electron microscopy, and photoluminescent spectroscopy. Photoluminescence was shown to be higher from samples synthesized in a CO2 plasma.

  3. Laser-assisted ultrathin bare die packaging: a route to a new class of microelectronic devices

    Science.gov (United States)

    Marinov, Val R.; Swenson, Orven; Atanasov, Yuriy; Schneck, Nathan

    2013-03-01

    Ultrathin flip-chip semiconductor die packaging on paper substrates is an enabling technology for a variety of extremely low-cost electronic devices with huge market potential such as RFID smart forms, smart labels, smart tickets, banknotes, security documents, etc. Highly flexible and imperceptible dice are possible only at a thickness of less than 50 μm, preferably down to 10-20 μm or less. Several cents per die cost is achievable only if the die size is <= 500 μm/side. Such ultrathin, ultra-small dice provide the flexibility and low cost required, but no conventional technology today can package such die onto a flexible substrate at low cost and high rate. The laser-enabled advanced packaging (LEAP) technology has been developed at the Center for Nanoscale Science and Engineering, North Dakota State University in Fargo, North Dakota, to accomplish this objective. Presented are results using LEAP to assemble dice with various thicknesses, including 350 μm/side dice as thin as 20 μm and less. To the best of our knowledge, this is the first report of using a laser to package conventional silicon dice with such small size and thickness. LEAP-packaged RFID-enabled paper for financial and security applications is also demonstrated. The cost of packaging using LEAP is lower compared to the conventional pick-and-place methods while the rate of packaging is much higher and independent of the die size.

  4. Manipulation of Self-Assembled Microparticle Chains by Electroosmotic Flow Assisted Electrorotation in an Optoelectronic Device

    Directory of Open Access Journals (Sweden)

    Xiaolu Zhu

    2015-09-01

    Full Text Available A method incorporating the optically induced electrorotation (OER and alternating current electroosmotic (ACEO effects, for the formation and motion control of microparticle chains, is numerically and experimentally demonstrated. In this method, both the rotating electric field and ACEO fluid roll are generated around the border between light and dark area of the fluidic chamber in an optoelectronic tweezers (OET device. The experimental results show that the particle chains can self-rotate in their pitch axes under the rotating electric field produced due to the different impedances of the photoconductive layer in light and dark areas, and have a peak self-rotating rate at around 1 MHz. The orbital movement of entire particle chain around the center of ACEO fluid roll can be achieved from 0.5 to 600 kHz. The strength of OER motion and ACEO-caused orbital movement of particle chains can be adjusted by changing the frequency of alternating current (AC voltage. This non-contact method has the potential for spatially regulating the posture, orientation and position of microparticle chains.

  5. Rf-assisted current startup in the Fusion Engineering Device (FED)

    Energy Technology Data Exchange (ETDEWEB)

    Borowski, S.K.; Peng, Y.K.M.; Kammash, T.

    1982-08-01

    Auxiliary rf heating of electrons before and during the current rise phase in the Fusion Engineering Device is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation 1 to 2 MW of electron cyclotron resonance heating (ECRH) power at approx. 90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10/sup 13/ cm/sup -3/) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a/sub o/ approx. = 0.2 to 0.4 m) current channel to be established with a relatively low initial loop voltage (less than or equal to 25 V). During the subsequent plasma expansion and current ramp phase, additional rf power is introduced to reduce volt-second consumption due to plasma resistance. A near classical particle and energy transport model has been developed to estimate the efficiency of electron heating in a currentless toroidal plasma. The model assumes that preferential electron heating at the UHR leads to the formation of an ambipolar sheath potential between the neutral plasma and the conducting vacuum vessel and limiter. The ambipolar electric field (E/sub AMB/) enables the plasma to neutralize itself via poloidal E vector/sub AMB/ x B vector drift. This form of effective rotational transform short-circuits the vertical charge separation and improves particle confinement.

  6. Results of endoscopic vacuum-assisted closure device for treatment of upper GI leaks.

    Science.gov (United States)

    Bludau, Marc; Fuchs, Hans F; Herbold, Till; Maus, Martin K H; Alakus, Hakan; Popp, Felix; Leers, Jessica M; Bruns, Christiane J; Hölscher, Arnulf H; Schröder, Wolfgang; Chon, Seung-Hun

    2018-04-01

    Esophageal perforations and postoperative leakage of esophagogastrostomies are considered to be life-threatening conditions due to the potential development of mediastinitis and consecutive sepsis. Vacuum-assisted closure (VAC) techniques, a well-established treatment method for superficial infected wounds, are based on a negative pressure applied to the wound via a vacuum-sealed sponge. Endoluminal VAC (E-VAC) therapy as a treatment for GI leakages in the rectum was introduced in 2008. E-VAC therapy is a novel method, and experience regarding esophageal applications is limited. In this retrospective study, the experience of a high-volume center for upper GI surgery with E-VAC therapy in patients with leaks of the upper GI tract is summarized. To our knowledge, this series presents the largest patient cohort worldwide in a single-center study. Between October 2010 and January 2017, 77 patients with defects in the upper gastrointestinal tract were treated using the E-VAC application. Six patients had a spontaneous perforation, 12 patients an iatrogenic injury, and 59 patients a postoperative leakage in the upper gastrointestinal tract. Complete restoration of the esophageal defect was achieved in 60 of 77 patients. The average duration of application was 11.0 days, and a median of 2.75 E-VAC systems were used. For 21 of the 77 patients, E-VAC therapy was combined with the placement of self-expanding metal stents. This study demonstrates that E-VAC therapy provides an additional treatment option for esophageal wall defects. Esophageal defects and mediastinal abscesses can be treated with E-VAC therapy where endoscopic stenting may not be possible. A prospective multi-center study has to be directed to bring evidence to the superiority of E-VAC therapy for patients suffering from upper GI defects.

  7. Biventricular MR volumetric analysis and MR flow quantification in the ascending aorta and pulmonary trunk for quantification of valvular regurgitation

    International Nuclear Information System (INIS)

    Rominger, M.B.

    2004-01-01

    Purpose: To test the value of biventricular volumetric analysis and the combination of biventricular volumetric analysis with flow quantification in the ascending aorta (Ao) and pulmonary trunk (Pu) for quantification of regurgitation volume and cardiac function in valvular regurgitation (VR) according to location and presence of single or multivalvular disease. Materials and Methods: In 106 patients, the stroke volumes were assessed by measuring the biventricular volumes and the forward-stroke volumes in the great and small circulation by measuring the flow in the Ao and Pu. Valve regurgitation volumes and quotients were calculated for single and multivalvular disease and correlated with semiquantitative 2D-echocardiography (grade I-IV). For the assessment of the cardiac function in VR, the volumetric parameters of ejection fraction and end-diastolic (EDV) and end-systolic (ESV) volumes were determined. Results: The detection rate was 49% for left ventricular (LV) VR and 42% for right ventricular (RV) VR. Low LV VR and RV VR usually could not be detected quantitatively, with the detection rate improving with echocardiographically higher insufficiency grades. Quantitative MRI could detect a higher grade solitary aortic valve insufficiency (≥2) in 11 of 12 patients and higher grade mitral valve insufficiency in 4 of 10 patients. A significant increase in RV and LV ventricular EDV and ESV was seen more often with increased MR regurgitation volumes. Aortic stenosis did not interfere with flow measurements in the Ao. Conclusions: Biventricular volumetry combined with flow measurements in Ao and Pu is a robust, applicable and simple method to assess higher grade regurgitation volumes and the cardiac function in single and multivalvular regurgitation at different locations. It is an important application for the diagnosis of VR by MRI [de

  8. Persistent atrial fibrillation worsens heart rate variability, activity and heart rate, as shown by a continuous monitoring by implantable biventricular pacemakers in heart failure patients.

    Science.gov (United States)

    Puglisi, Andrea; Gasparini, Maurizio; Lunati, Maurizio; Sassara, Massimo; Padeletti, Luigi; Landolina, Maurizio; Botto, Giovanni Luca; Vincenti, Antonio; Bianchi, Stefano; Denaro, Alessandra; Grammatico, Andrea; Boriani, Giuseppe

    2008-07-01

    Atrial fibrillation (AF) induces loss of atrial contribution, heart rate irregularity, and fast ventricular rate. The objectives of the study were to accurately measure AF incidence and to investigate the mutual temporal patterns of AF and heart failure (HF) in patients indicated to cardiac resynchronization therapy. Four hundred ten consecutive patients (70% male, age 69 +/- 11) with advanced HF (NYHA = 3.0 +/- 0.6), low ejection fraction (EF = 27 +/- 9%), and ventricular conduction delay (QRS = 165 +/- 29 ms) received a biventricular pacemaker. Enrolled patients were divided into two groups: G1 = 249 patients with no AF history, G2 = 161 patients with history of paroxysmal/persistent AF. In a median follow-up of 13 months, AF episodes longer than 5 minutes occurred in 105 of 249 (42.2%) G1 patients and 76 of 161 (47.2%) G2 patients, while AF episodes longer than one day occurred in 14 of 249 (5.6%) G1 patients and in 36 of 161 (22.4%) G2 patients. Device diagnostics monitored daily values of patient activity, night heart rate (NHR), and heart rate variability (HRV). Comparing 30-day periods before AF onset and during persistent AF, significant (P R(2)= 0.73) with activity, with a significant lower activity associated with NHR >or= 88 bpm. AF is frequent in HF patients. Persistent AF is associated with statistically significant decrease in patient activity and HRV and NHR increase.

  9. Systematic Review of Studies Promoting the Use of Assistive Technology Devices by Young Children with Disabilities. Practical Evaluation Reports, Volume 5, Number 1

    Science.gov (United States)

    Dunst, Carl J.; Trivette, Carol M.; Hamby, Deborah W.; Simkus, Andrew

    2013-01-01

    Findings from a meta-analysis of studies investigating the use of five different assistive technology devices (switch interfaces, powered mobility, computers, augmentative communication, weighted/pressure vests) with young children with disabilities are reported. One hundred and nine studies including 1,342 infants, toddlers, and preschoolers were…

  10. Central and peripheral blood flow during exercise with a continuous-flow left ventricular assist device: constant versus increasing pump speed: a pilot study

    DEFF Research Database (Denmark)

    Brassard, Patrice; Jensen, Annette S; Nordsborg, Nikolai

    2011-01-01

    Background- End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed...

  11. Medical Management of Pump-Related Thrombosis in Patients with Continuous-Flow Left Ventricular Assist Devices: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Dang, Geetanjali; Epperla, Narendranath; Muppidi, Vijayadershan; Sahr, Natasha; Pan, Amy; Simpson, Pippa; Baumann Kreuziger, Lisa

    Pump thrombosis is a dreaded complication of left ventricular assist devices (LVADs). We completed a systematic review to evaluate the efficacy and complications associated with medical management of LVAD thrombosis. Databases were searched using the terms "vad*" or "ventricular assist device" or "heart assist device" and "thrombus" or "thrombosis" or "thromboembolism." Of 2,383 manuscripts, 49 articles met the inclusion criteria. The risk of partial or no resolution of LVAD thrombosis did not significantly differ between thrombolytic and nonthrombolytic regimens (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.20-1.16). When response to therapy was evaluated based on pump type, there were no significant differences in how patients with a HeartMate II or HeartWare ventricular assist device responded to thrombolytic or nonthrombolytic treatment. Pooled risk of major bleeding in the thrombolytic group was 29% (95% CI, 0.17-0.44) and 12% (95% CI, 0.01-0.57) in the nonthrombolytic group. Odds of death did not differ between thrombolytic and nonthrombolytic regimens (OR, 1.28; 95% CI, 0.42-3.89). Although thrombolytic and nonthrombolytic treatment similarly resolved LVAD thrombosis, major hemorrhage may be increased with the use of thrombolysis. Randomized clinical trials comparing thrombolytic and nonthrombolytic treatment of LVAD thrombosis are needed to establish the most effective and safe option for patients who are not surgical candidates.

  12. Severely impaired von Willebrand factor-dependent platelet aggregation in patients with a continuous-flow left ventricular assist device (HeartMate II)

    DEFF Research Database (Denmark)

    Klovaite, Jolanta; Gustafsson, Finn; Mortensen, Svend A

    2009-01-01

    OBJECTIVES: This study investigated the influence of the mechanical blood pump HeartMate II (HMII) (Thoratec Corporation, Pleasanton, California) on blood coagulation and platelet function. BACKGROUND: HMII is an implantable left ventricular assist device used for the treatment of heart failure...

  13. Cardiogenic Shock due to Psychosis-Induced Inverted Takotsubo Cardiomyopathy Bridged-to-Recovery with a Percutaneous Left Ventricular Assist Device

    Directory of Open Access Journals (Sweden)

    Ravi Korabathina

    2016-01-01

    Full Text Available Inverted Takotsubo cardiomyopathy, a less common variant in the spectrum of stress-induced cardiomyopathy, is increasingly being reported. This report describes an acute psychiatric illness leading to the onset of this syndrome. The patient presented here developed cardiogenic shock but successfully recovered with the use of a percutaneous left ventricular assist device.

  14. HeartWare Ventricular Assist Device Placement in a Patient With Corrected Dextro-Transposition of Great Arteries: A Case Report and Its Clinical Challenges.

    Science.gov (United States)

    Sehgal, Sankalp; Ramachandran, Sujatha; Leff, Jonathan D

    2015-09-01

    Given the improved survival in patients with corrected dextro-transposition of great arteries (D-TGA), it has evolved into an adult congenital heart defect. It is important to understand the management and complications observed in this population that eventually progresses to systemic ventricular failure requiring cardiac transplantation. Our case focuses on the rapid right ventricle (RV) deterioration of a patient with corrected D-TGA following a surgical procedure requiring systemic support. With such patients awaiting heart transplantation, there are limited assist devices available for RV support and no right ventricular assist device is approved for destination therapy yet. Current indications for implantation of the HeartWare ventricular assist device (HVAD) are limited by the Food and Drug Administration (FDA) to the left ventricle support as a bridge to transplantation. However, its use in the United States for right-sided support has rarely been described for adult congenital defects. In this case, a HeartWare assist device was used to provide systemic support as a bridge to cardiac transplant. The size and implantation design of the HVAD makes it a promising option for patients with this challenging patient population and RV failure as a late complication. © The Author(s) 2015.

  15. Biventricular repair versus uni-ventricular repair for pulmonary atresia with intact ventrical septum: A systematic review.

    Science.gov (United States)

    Li, Fei-fei; Du, Xin-ling; Chen, Shu

    2015-10-01

    The management of pulmonary atresia with intact ventricular septum (PA/IVS) remains controversial. The goal of separating systematic and pulmonary circulation can be achieved by biventricular or uni-ventricular (Fontan or one and a half ventricle repair) strategies. Although outcomes have been improved, these surgical procedures are still associated with high mortality and morbidity. An optimal strategy for definitive repair has yet to be defined. We searched databases for genetically randomized controlled trials (RCTs) comparing biventricular with uni-ventricular repair for patient with PA/IVS. Data extraction and quality assessment were performed following the guidelines of the Cochrane Collaboration. Primary outcome measures were overall survival, and secondary criteria included exercise function, arrhythmia-free survival and treatment-related mortality. A total number of 669 primary citations were screened for relevant studies. Detailed analysis revealed that no RCTs were found to adequately address the research question and no systematic meta-analysis would have been carried out. Nevertheless, several retrospective analyses and case series addressed the question of finding right balance between biventricular and uni-ventricular repair for patient with PA/IVS. In this review, we will discuss the currently available data.

  16. Percutaneous excisional biopsy of clinically benign breast lesions with vacuum-assisted system: comparison of three devices.

    Science.gov (United States)

    Wang, Zhi Li; Liu, Gang; Huang, Yan; Wan, Wen Bo; Li, Jun Lai

    2012-04-01

    The aim of this study was to compare three devices in percutaneous excisional biopsy of clinically benign breast lesions in terms of complete excision rate, duration of procedure and complications. In a retrospective study from March 2005 to May 2009, 983 lesions underwent ultrasound-guided excisional biopsy with three vacuum-assisted systems, respectively. The lesions were category 3 lesions as determined by ultrasound imaging according to Breast Imaging Reporting and Data System (BI-RADS) (n=951) or had been confirmed as benign by a previous core needle biopsy (n=32). The completely excision rate, duration of procedure and complications (hematoma, pain and ecchymosis) were recorded. 99.7% (980/983) lesions were demonstrated to be benign by pathology after percutaneous excisional biopsy. The overall complete excision rate was 94.8% (932/983). In lesions whose largest diameter equal to or larger than 1.5cm, the complete excision rates of EnCor(®) group (97.8%, 348/356) and Mammotome(®) group (97.2%, 139/143) were significantly higher than that of Vacora(®) group (91.9%, 445/484) (P<0.05). The EnCor(®) group (6.6±6.5min) had a significant less duration than Mammotome(®) (10.6±9.3min) and Vacora(®) group (25.6±23.3min) (P<0.05). Hematoma occurred more in EnCor(®) group and Mammotome(®) group than in Vacora(®) group (P<0.05). All these three vacuum-assisted systems are highly successful for excisional biopsy of benign breast lesions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. Microwave-assisted extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs) used to indoor air monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Esteve-Turrillas, Francesc A. [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain); Pastor, Agustin [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain)]. E-mail: agustin.pastor@uv.es; Guardia, Miguel de la [Analytical Chemistry Department, University of Valencia, Edifici Jeroni Munoz, 50th Dr. Moliner, 46100 Burjassot, Valencia (Spain)

    2006-02-23

    A rapid and environmentally friendly methodology was developed for the extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs), in which they were preconcentrated in gas phase. The method was based on gas chromatography mass-mass spectrometry determination after a microwave-assisted extraction, in front of the widely employed dialysis method. SPMDs were extracted twice with 30 mL hexane:acetone, irradiated with 250 W power output, until 90 deg. C in 10 min, this temperature being held for another 10 min. Clean-up of the extracts was performed by acetonitrile-hexane partitioning and solid-phase extraction (SPE) with a combined cartridge of 2 g basic-alumina, deactivated with 5% water, and 500 mg C{sub 18}. Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, {lambda}-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flucythrinate, Esfenvalerate, Fluvalinate and Deltamethrin. The main pyrethroid synergist compound, Pyperonyl Butoxide, was also studied. Limit of detection values ranging from 0.3 to 0.9 ng/SPMD and repeatability data, as relative standard deviation, from 2.9 to 9.4%, were achieved. Pyrethroid recoveries, for spiked SPMDs, with 100 ng of each one of the pyrethroids evaluated, were from 61 {+-} 8 to 103 {+-} 7% for microwave-assisted extraction, versus 54 {+-} 4 to 104 {+-} 3% for dialysis reference method. Substantial reduction of solvent consumed (from 400 to 60 mL) and analysis time (from 48 to 1 h) was achieved by using the developed procedure. High concentration levels of pyrethroid compounds, from 0.14 to 7.3 {mu}g/SPMD, were found in indoor air after 2 h of a standard application.

  18. Microwave-assisted extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs) used to indoor air monitoring

    International Nuclear Information System (INIS)

    Esteve-Turrillas, Francesc A.; Pastor, Agustin; Guardia, Miguel de la

    2006-01-01

    A rapid and environmentally friendly methodology was developed for the extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs), in which they were preconcentrated in gas phase. The method was based on gas chromatography mass-mass spectrometry determination after a microwave-assisted extraction, in front of the widely employed dialysis method. SPMDs were extracted twice with 30 mL hexane:acetone, irradiated with 250 W power output, until 90 deg. C in 10 min, this temperature being held for another 10 min. Clean-up of the extracts was performed by acetonitrile-hexane partitioning and solid-phase extraction (SPE) with a combined cartridge of 2 g basic-alumina, deactivated with 5% water, and 500 mg C 18 . Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, λ-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flucythrinate, Esfenvalerate, Fluvalinate and Deltamethrin. The main pyrethroid synergist compound, Pyperonyl Butoxide, was also studied. Limit of detection values ranging from 0.3 to 0.9 ng/SPMD and repeatability data, as relative standard deviation, from 2.9 to 9.4%, were achieved. Pyrethroid recoveries, for spiked SPMDs, with 100 ng of each one of the pyrethroids evaluated, were from 61 ± 8 to 103 ± 7% for microwave-assisted extraction, versus 54 ± 4 to 104 ± 3% for dialysis reference method. Substantial reduction of solvent consumed (from 400 to 60 mL) and analysis time (from 48 to 1 h) was achieved by using the developed procedure. High concentration levels of pyrethroid compounds, from 0.14 to 7.3 μg/SPMD, were found in indoor air after 2 h of a standard application

  19. Ventricular Assist Device Implant in the Elderly Is Associated With Increased, but Respectable Risk: A Multi-Institutional Study

    Science.gov (United States)

    Atluri, Pavan; Goldstone, Andrew B.; Kobrin, Dale M.; Cohen, Jeffrey E.; Rame, J. Eduardo; Acker, Michael A.; Woo, Y. Joseph

    2014-01-01

    Background There are an increasing number of elderly patients with end-stage heart failure. Destination mechanical circulatory support is often the only therapy available for these patients who are not transplant candidates. The outcomes after continuous flow left ventricular assist device (CF LVAD) implant in older patients remains unclear. We undertook this multi-institutional study to quantify short-term and midterm outcomes after CF LVAD implant in the elderly. Methods We retrospectively analyzed all patients in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) national registry that underwent implant of a CF LVAD (June 2006 to April 2012). Patients were divided into 2 cohorts based upon age (<70 years [n = 4,439] and ≥70 years (n = 590]). Preoperative, intraoperative, and postoperative variables were analyzed. The primary endpoint, survival, was compared between cohorts. Results Patients age 70 and older were more hemodynamically stable pre-VAD implant as evidenced by INTERMACS profile and inotrope dependence. Perioperative outcomes, including median bypass time (89 vs 89 minutes) and length of stay (0.657 vs 0.657 months) were similar between cohorts (p = not significant). Kaplan-Meier analysis revealed a significant difference in 2-year survival between patients aged 70 years or greater (63%) and less than 70 (71%, p < 0.001). Multivariable Cox proportional hazard analysis revealed age as an independent predictor of mortality during follow-up (p < 0.001). Nonetheless, midterm cumulative survival in the older cohort was still reasonable (63% at 2 years). Conclusions Multi-institutional analysis revealed advanced age as a predictor of increased mortality after CF LVAD implantation. Careful patient selection is critical in the elderly to optimize long-term outcomes after CF LVAD implantation. PMID:23731606

  20. The Lazarus Funnel: a blinded prospective randomized in vitro trial of a novel CE-marked thrombectomy assist device.

    Science.gov (United States)

    Fargen, Kyle M; Mocco, J; Gobin, Y Pierre

    2016-01-01

    The use of retrievable stents for acute ischemic stroke (AIS) may result in the release of distal emboli in 12-22% of cases. The Lazarus Funnel is a novel CE-marked thrombectomy assist device designed to capture the stentriever and thrombus to minimize the likelihood of distal embolization. To study this technology, we performed a randomized blinded in vitro evaluation of this device. A cerebral flow model was used as an in vitro simulator for cerebral arterial thrombectomy procedures. Stratified block randomization was performed following embolus injection into one of three cohorts: Solitaire stentriever plus guide catheter (control); control plus proximal Funnel placement; or control plus distal Funnel placement. Time to embolectomy, recanalization, and incidence of distal emboli were determined by a blinded observer. Forty-five thrombectomy trials were performed (15 in each group). The average time required for thrombectomy in each group was 8 min 26 s, 11 min 0 s and 9 min 24 s, respectively (p=NS). Use of the Funnel was associated with significantly improved recanalization compared with stentriever alone (pFunnel resulted in a 25% increase in successful recanalization and a 20% reduction in distal emboli. Use of the distal Funnel resulted in a 200% increase in successful recanalization and a 60% reduction in emboli. In this AIS embolism flow model with Solitaire thrombectomy, the Lazarus Funnel resulted in a significant increase in recanalization and significant reduction in distal emboli without increase in time to recanalization. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Post-transplant outcomes in pediatric ventricular assist device patients: A PediMACS-Pediatric Heart Transplant Study linkage analysis.

    Science.gov (United States)

    Sutcliffe, David L; Pruitt, Elizabeth; Cantor, Ryan S; Godown, Justin; Lane, John; Turrentine, Mark W; Law, Sabrina P; Lantz, Jodie L; Kirklin, James K; Bernstein, Daniel; Blume, Elizabeth D

    2017-12-13

    Pediatric ventricular assist device (VAD) support as bridge to transplant has improved waitlist survival, but the effects of pre-implant status and VAD-related events on post-transplant outcomes have not been assessed. This study is a linkage analysis between the PediMACS and Pediatric Heart Transplant Study databases to determine the effects of VAD course on post-transplant outcomes. Database linkage between October 1, 2012 and December 31, 2015 identified 147 transplanted VAD patients, the primary study group. The comparison cohort was composed of 630 PHTS patients without pre-transplant VAD support. The primary outcome was post-transplant survival, with secondary outcomes of post-transplant length of stay, freedom from infection and freedom from rejection. At implant, the VAD cohort was INTERMACS Profile 1 in 33 (23%), Profile 2 in 89 (63%) and Profile 3 in 14 (10%) patients. The VAD cohort was older, larger, and less likely to have congenital heart disease (p < 0.0001). However, they had greater requirements for inotrope and ventilator support and increased liver and renal dysfunction (p < 0.0001), both of which normalized at transplant after device support. Importantly, there were no differences in 1-year post-transplant survival (96% vs 93%, p = 0.3), freedom from infection (81% vs 79%, p = 0.9) or freedom from rejection (71% vs 74%, p = 0.87) between cohorts. Pediatric VAD patients have post-transplant outcomes equal to that of medically supported patients, despite greater pre-implant illness severity. Post-transplant survival, hospital length of stay, infection and rejection were not affected by patient acuity at VAD implantation or VAD-related complications. Therefore, VAD as bridge to transplant mitigates severity of illness in children. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  2. Prospective Randomized Evaluation of Implantable Cardioverter-Defibrillator Programming in Patients With a Left Ventricular Assist Device.

    Science.gov (United States)

    Richardson, Travis D; Hale, Leslie; Arteaga, Christopher; Xu, Meng; Keebler, Mary; Schlendorf, Kelly; Danter, Matthew; Shah, Ashish; Lindenfeld, JoAnn; Ellis, Christopher R

    2018-02-23

    Ventricular arrhythmias are common in patients with left ventricular assist devices (LVADs) but are often hemodynamically tolerated. Optimal implantable cardioverter defibrillator (ICD) tachy-programming strategies in patients with LVAD have not been determined. We sought to determine if an ultra-conservative ICD programming strategy in patients with LVAD affects ICD shocks. Adult patients with an existing ICD undergoing continuous flow LVAD implantation were randomized to standard ICD programming by their treating physician or an ultra-conservative ICD programming strategy utilizing maximal allowable intervals to detection in the ventricular fibrillation and ventricular tachycardia zones with use of ATP. Patients with cardiac resynchronization therapy (CRT) devices were also randomized to CRT ON or OFF. Patients were followed a minimum of 6 months. The primary outcome was time to first ICD shock. Among the 83 patients studied, we found no statistically significant difference in time to first ICD shock or total ICD shocks between groups. In the ultra-conservative group 16% of patients experienced at least one shock compared with 21% in the control group ( P =0.66). There was no difference in mortality, arrhythmic hospitalization, or hospitalization for heart failure. In the 41 patients with CRT ICDs fewer shocks were observed with CRT-ON but this was not statistically significant: 10% of patients with CRT-ON (n=21) versus 38% with CRT-OFF (n=20) received shocks ( P =0.08). An ultra-conservative programming strategy did not reduce ICD shocks. Programming restrictions on ventricular tachycardia and ventricular fibrillation zone therapy should be reconsidered for the LVAD population. The role of CRT in patients with LVAD warrants further investigation. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01977703. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  3. Modification of self-concept in patients with a left-ventricular assist device: an initial exploration.

    Science.gov (United States)

    Marcuccilli, Linda; Casida, Jesus; Peters, Rosalind M

    2013-09-01

    To explore how patients with left-ventricular assist devices (LVAD) meet the health-deviation requisite of modifying self-concept to accept this form of treatment and restore normalcy. LVAD are becoming a standard option to improve the quality of life for patients with advanced heart failure. Past research focused on technology issues and survival rates, but limited research has addressed the effect of LVADs on patients' perceptions of self. Orem's theory of self-care provides a framework to investigate how patients manage threats to self-concept to safely live with such a device. Hermeneutic phenomenology based on van Manen's method. Data were collected using semi-structured interviews. Data saturation was achieved with nine participants (seven men; two women), 31-70 years of age who lived with a LVAD at home for at least three months. Thematic analysis was ongoing, and final themes were consensually validated. Two themes constructed from the data were consistent with the requisite of modifying self-concept. First, Having a LVAD means living. Participants described they 'feel alive again', and they 'had the rest of [their] lives that they didn't have before'. The second theme: A desire to be 'normal' in public, arose from participants descriptions of how the LVAD brought unwanted attention to them and that their appearance was 'shocking' to others. Participants accepted the LVAD as necessary to live making it easier for them to modify their self-concept and accept the changes to their bodies and daily lives. Attaining a sense of normalcy was more difficult in public and required additional lifestyle modifications. Findings advance self-care knowledge in LVAD management and can heighten nurses' awareness about self-concept as a vital component for maintenance of health and well-being. © 2013 Blackwell Publishing Ltd.

  4. Electrophysiologic characteristics and catheter ablation of ventricular tachyarrhythmias among patients with heart failure on ventricular assist device support.

    Science.gov (United States)

    Cantillon, Daniel J; Bianco, Christopher; Wazni, Oussama M; Kanj, Mohamed; Smedira, Nicholas G; Wilkoff, Bruce L; Starling, Randall C; Saliba, Walid I

    2012-06-01

    Ventricular tachyarrhythmias (VT) are common among ventricular assist device (VAD) recipients, yet electrophysiologic (EP) characteristics and catheter ablation outcomes remain uncharacterized. To evaluate the EP characteristics and catheter ablation outcomes for VTs among heart failure patients on VAD support. The Cleveland Clinic registry of consecutive patients undergoing VAD placement in 1991-2010 with medically refractory, symptomatic VT referred for EP study and catheter ablation. Among 611 recipients of VAD (mean age 53.3 ± 12.4 years, 80% men), 21 patients (3.4%) were referred for 32 EP procedures, including 11 patients (52%) presenting with implantable cardioverter-defibrillator therapy (13 shocks, 26 antitachycardia pacing). Data from 44 inducible tachycardias (mean cycle length 339 ± 59 ms) demonstrated monomorphic VT (n = 40, 91%; superior axis 52%, right bundle branch block morphology 41%) and polymorphic ventricular tachycardia (PMVT)/ventricular fibrillation (n = 4, 8%). Electroanatomic mapping of 28 tachycardias in 20 patients demonstrated reentrant VT related to intrinsic scar (n = 21 of 28, 75%) more commonly than the apical inflow cannulation site (n = 4 of 28, 14%), focal/microreentry VT (n = 2 of 28, 7%), or bundle branch reentry (n = 1 of 28, 3.5%). Catheter ablation succeeded in 18 of 21 patients (86%). VT recurred in 7 of 21 patients (33%) at a mean of 133 ± 98 days, and 6 patients (29%) required repeat procedures, with subsequent recurrence in 4 of 21 patients (19%). Catheter ablation of VT is effective among recipients of VAD. Intrinsic myocardial scar, rather than the apical device cannulation site, appears to be the dominant substrate. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  5. An experimental evaluation of the non-Newtonian scaling effects in a rotodynamic left ventricular assist device

    Science.gov (United States)

    Miklosovic, David Scott

    Significant work has been done in the last 10 years to advance the technology of long-term mechanical circulatory assistance, particularly the left ventricular assist device (LVAD). Traditionally, rotary LVADs have been developed using conventional fluid dynamic design methods and Newtonian scaling laws, since non-Newtonian effects were previously assumed to be of second-order importance. To evaluate centrifugal pump performance scaling and flow patterns in a non-Newtonian fluid, the Large-Scale Rotor Testbed (LSRT) at The Ohio State University was developed to test two 9X-scale blood pump impellers in a baseline volute housing of the Innovative Ventricular Assist System (IVAS) designed by the Cleveland Clinic Foundation. Non-Newtonian fluids yielded pump performance deficits of first-order importance, or up to 11% of the Newtonian performance. Thus, the non-Newtonian effects were of the same magnitude as substantial variations in the impeller geometry. Moreover, the dimensionless pressure- and flow-coefficients showed that the non-Newtonian performance deviated from the similarity laws at critical Reynolds numbers that were 2.4--2.7 times higher than the Newtonian value of 71,000. Above the critical Reynolds number, the non-Newtonian fluids followed a similarity behavior, but it was different from the Newtonian case. The deviation increased with the magnitude of shear-thinning behavior as measured by the Weissenberg number. Shear-thinning xanthan gum solutions were used as non-Newtonian test fluids in concentrations from 0 to 1,200 ppm. Fluid samples were characterized in a Couette rheometer to determine viscosity behavior, biological degradation, and shear-induced polymer chain breakdown. The solutions proved to be stable and useful for a duration of up to two weeks of routine LSRT testing. Because the LSRT pump operates in a low-specific speed, low-flow regime, flow visualizations revealed a strong adverse pressure gradient and a prominent inverse Ekman layer in

  6. Osteopathic treatment in a patient with left-ventricular assist device with left brachialgia: a case report

    Directory of Open Access Journals (Sweden)

    Bordoni B

    2017-01-01

    Full Text Available Bruno Bordoni,1–3 Fabiola Marelli,2,3 Bruno Morabito,2–4 Beatrice Sacconi5 1Foundation Don Carlo Gnocchi IRCCS, Department of Cardiology, Institute of Hospitalization and Care with Scientific Address, Milan, 2CRESO, School of Osteopathic Centre for Research and Studies, Gorla Minore, 3CRESO, School of Osteopathic Centre for Research and Studies, Falconara Marittima, 4Department of Radiological, Oncological and Anatomopathological Sciences, Sapienza University of Rome, 5Center for Life Nano Science, CLNS@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy Abstract: This study deals with an osteopathic approach used for a patient with left-ventricular assist device (L-VAD affected by left brachialgia. Clinical examination revealed the presence of thoracic outlet syndrome and pectoralis minor syndrome, with compression of the left proximal ulnar nerve, related to the surgical sternotomy performed. The osteopathic techniques used can be classified as indirect and direct, addressed to the pectoralis minor and the first left rib, respectively. To our knowledge, this is the first text in literature with an osteopathic treatment in a patient with L-VAD. Keywords: osteopathic, L-VAD, thoracic outlet syndrome, TOS, myofascial, fascia

  7. Preliminary design of the internal geometry in a minimally invasive left ventricular assist device under pulsatile-flow conditions.

    Science.gov (United States)

    Smith, P Alex; Wang, Yaxin; Metcalfe, Ralph W; Sampaio, Luiz C; Timms, Daniel L; Cohn, William E; Frazier, O H

    2018-03-01

    A minimally invasive, partial-assist, intra-atrial blood pump has been proposed, which would unload the left ventricle with a flow path from the left atrium to the arterial system. Flow modulation is a common strategy for ensuring washout in the pump, but it can increase power consumption because it is typically achieved through motor-speed variation. However, if a pump's performance curve had the proper gradient, flow modulation could be realized passively. To achieve this goal, we propose a pump performance operating curve as an alternative to the more standard operating point. Mean-line theory was employed to generate an initial set of geometries that were then tested on a hydraulic test rig at ~20,000 r/min. Experimental results show that the intra-atrial blood pump performed below the operating region; however, it was determined that smaller hub diameter and longer chord length bring the performance of the intra-atrial blood pump device closer to the operating curve. We found that it is possible to shape the pump performance curve for specifically targeted gradients over the operating region through geometric variations inside the pump.

  8. "Do I need it? Do I really need it?" Elderly peoples experiences of unmet assistive technology device needs.

    Science.gov (United States)

    Gramstad, Astrid; Storli, Sissel Lisa; Hamran, Torunn

    2013-07-01

    An unmet need for assistive technology devices (ATD) occurs when a person would benefit from ATD, as assessed by health-care professionals or by the person In question. Unmet ATD needs In the elderly population have been documented, but little is known about the experience of living with such unmet needs. To investigate the unmet need experiences of home-dwelling elderly people In Norway who have applied for ATD. Nine elderly people who lived at home and had applied for ATD were interviewed. The interview transcripts were analysed withIn a hermeneutical phenomenological perspective. The unmet ATD need experiences involved enduring a difficult situation by adjusting their expectations and activities, being introduced to ATD as a possible solution to the difficulties and negotiating this potential solution In light of the perceived situation. Observers assessments of unmet ATD needs are not readily experienced as such by the elderly. Adjusting expectations and activities enabled the participants to maintaIn meaningful activities but also made the difficulties less likely to be articulated as unmet needs. When encountering elderly people, health-care professionals must be sensitive to the unarticulated needs and potential difficulties of the elderly In performing everyday activities.

  9. Construction of bioartificial renal tubule assist device in vitro and its function of transporting sodium and glucose.

    Science.gov (United States)

    Dong, Xinggang; Chen, Jianghua; He, Qiang; Yang, Yi; Zhang, Wei

    2009-08-01

    To explore a new way of constructing bioartificial renal tubule assist device (RAD) in vitro and its function of transporting sodium (Na(+)) and glucose and to evaluate the application of atomic force microscope in the RAD construction, rat renal tubular epithelial cell line NRK-52E was cultured in vitro, seeded onto the outer surfaces of hollow fibers in a bioreactor, and then cultured for two weeks to construct RAD. Bioreactor hollow fibers without NRK-52E cells were used as control. The morphologies of attached cells were observed with scanning electron microscope, and the junctions of cells and polysulfone membrane were observed with atomic force microscope. Transportation of Na(+) and glucose was measured. Oubaine and phlorizin were used to inhibit the transporting property. The results showed that NRK-52E cells and polysulfone membrane were closely linked, as observed under atomic force microscope. After exposure to oubaine and phlorizin, transporting rates of Na(+) and glucose were decreased significantly in the RAD group as compared with that in the control group (Pconstructed successfully in vitro, and it is able to selectively transport Na(+) and glucose.

  10. End-of-life decision making and implementation in recipients of a destination left ventricular assist device.

    Science.gov (United States)

    Brush, Sally; Budge, Deborah; Alharethi, Rami; McCormick, Ashley J; MacPherson, Jane E; Reid, Bruce B; Ledford, Ian D; Smith, Hildegard K; Stoker, Sandi; Clayson, Stephen E; Doty, John R; Caine, William T; Drakos, Stavros; Kfoury, Abdallah G

    2010-12-01

    The use of left ventricular assist devices (LVADs) as destination therapy (DT) is increasing and has proven beneficial in prolonging survival and improving quality of life in select patients with end-stage heart failure. Nonetheless, end-of-life (EOL) issues are inevitable and how to approach them underreported. Our DT data registry was queried for eligible patients, defined as those individuals who actively participated in EOL decision making. The process from early EOL discussion to palliation and death was reviewed. We recorded the causes leading to EOL discussion, time from EOL decision to withdrawal and from withdrawal to death, and location. Primary caregivers were surveyed to qualify their experience and identify themes relevant to this process. Between 1999 and 2009, 92 DT LVADs were implanted in 69 patients. Twenty patients qualified for inclusion (mean length of support: 833 days). A decrease in quality of life from new/worsening comorbidities usually prompted EOL discussion. Eleven patients died at home, 8 in the hospital and 1 in a nursing home. Time from EOL decision to LVAD withdrawal ranged from closure and ensured comfort at EOL. With expanding indications and improved technology, more DT LVADs will be implanted and for longer durations, and more patients will face EOL issues. A multidisciplinary team approach with protocols involving DT patients and their families in EOL decision making allows for continuity of care and ensures dignity and comfort at EOL. Copyright © 2010 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  11. The effect of fluid viscosity on the hemodynamic energy changes during operation of the pulsatile ventricular assist device.

    Science.gov (United States)

    Ahn, Chi Bum; Son, Kuk Hui; Lee, Jung Joo; Choi, Jaesoon; Song, Seung Joon; Jung, Jae Seung; Lee, Sung Ho; Son, Ho Sung; Sun, Kyung

    2011-11-01

    Blood viscosity during operation of ventricular assist device (VAD) can be changed by various conditions such as anemia. It is known generally that the blood viscosity can affect vascular resistance and lead to change of blood flow. In this study, the effect of fluid viscosity variation on hemodynamic energy was evaluated with a pulsatile blood pump in a mock system. Six solutions were used for experiments, which were composed of water and glycerin and had different viscosities of 2, 2.5, 3, 3.5, 4, and 4.5 cP. The hemodynamic energy at the outlet cannula was measured. Experimental results showed that mean pressure was increased in accordance with the viscosity increase. When the viscosity increased, the mean pressure was also increased. However, the flow was decreased according to the viscosity increase. Energy equivalent pressure value was increased according to the viscosity-induced pressure rise; however, surplus hemodynamic energy value did not show any apparent changing trend. The hemodynamic energy made by the pulsatile VAD was affected by the viscosity of the circulating fluid. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  12. Exertional Angina Due To Fused Aortic Bioprosthesis During Left Ventricular Assist Device Support: Two Cases and Review of the Literature.

    Science.gov (United States)

    Bonios, Michael J; Selzman, Craig H; Gilbert, Edward M; McKellar, Stephen H; Koliopoulou, Antigoni; Strege, Jennifer L; Nativi, Jose N; Fang, James C; Stehlik, Josef; Drakos, Stavros G

    We present the case of two patients with idiopathic dilated cardiomyopathy and moderate aortic valve regurgitation that were treated with a bioprosthetic valve at the time of the left ventricular assist device (LVAD) implantation. A few months later, patients revealed partial recovery in the left ventricle systolic function. Both patients, during the LVAD turndown protocol, reported the onset of chest pain. The transthoracic echocardiography revealed the presence of a new transaortic pressure gradient. We confirmed the presence of a fused bioprosthetic valve by further performing a transesophageal echocardiogram and a left and right heart catheterization. Replacement of aortic valve at the time of an LVAD implantation constitutes a challenging case. Although a mechanical valve is contraindicated due to the increased thromboembolic risk, selecting a bioprosthetic valve increases the risk of valve leaflets fusion. The consequences of this phenomenon should be acknowledged in LVAD patients undergoing aortic valve replacement with a bioprosthetic, especially under the view of LVAD explantation for those revealing myocardial recovery under mechanical unloading.

  13. Changes in Total Cardiac Output and Oxygen Extraction During Exercise in Patients Supported With an HVAD Left Ventricular Assist Device.

    Science.gov (United States)

    Schmidt, Thomas; Bjarnason-Wehrens, Birna; Mommertz, Stephanie; Hannig, Meike; Schulte-Eistrup, Sebastian; Willemsen, Detlev; Reiss, Nils

    2018-02-12

    Following implantation of a left ventricular assist device (LVAD), acceptable functional performance is now being achieved; however, peak VO 2 and peak work load (watts) remain considerably limited. Maximum physical capacity is essentially dependent on generated cardiac output (CO) and arteriovenous oxygen difference (avDO 2 ). We investigated the changes in CO and avDO 2 during exercise in LVAD patients with an HVAD pump (HeartWare Inc., Framingham, MA, USA). Approximately 6 weeks after implantation, 20 patients (100% male, 60.8 ± 7.3 years old, BMI 25.7 ± 3.3) underwent a six-minute walk test (6MWT), a cardiopulmonary exercise test (CPET), and noninvasive hemodynamic measurement. The mean six-minute walking distance (6MWD) was 403 m (68% of predicted), and mean peak VO 2 was 10.9 mL/kg/min (39% of predicted). Mean total CO improved from 3.8 L at rest to 7.0 L at maximum exercise. The mean avDO 2 increased from 7.4 mL/dL (44% of oxygen content) at rest to 13.2 mL/dL (75% of oxygen content) at maximum exercise. There was a significant increase in both total CO (P parameters. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  14. How self-care education in ventricular assist device programs is organized and provided: a national study.

    Science.gov (United States)

    Widmar, S Brian; Dietrich, Mary S; Minnick, Ann F

    2014-01-01

    To describe the care delivery structure and elements used for patient self-care education in ventricular assist device (VAD) programs. Use of VADs as destination therapy and to sustain organ function until cardiac transplantation has increased 517% since 2007. Elements of VAD-specific self-care education have not been described. A 26-item survey measuring VAD self-care education resource use, organizational, employment, behavioral and labor variables was sent to VAD coordinators at all US VAD centers (N = 111) in 2011. Two subsequent mailings yielded a 63% (n = 71) return rate. Analysis included descriptive statistics and cluster analysis. Element use varied across programs. Reliance on single educational and evaluation methods, and lack of return demonstration were noted. VAD coordinators reported extensive caregiver, hospital provider, and community educational responsibilities in addition to patient self-care education. VAD self-care education programs varied by hospital. Future research is needed to determine if specific care delivery structures or elements used in self-care education improve VAD patient outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Template-assisted selective epitaxy of III–V nanoscale devices for co-planar heterogeneous integration with Si

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, H., E-mail: sih@zurich.ibm.com; Borg, M.; Moselund, K.; Cutaia, D.; Riel, H. [IBM Research – Zurich, 8803 Rüschlikon (Switzerland); Gignac, L.; Breslin, C. M.; Bruley, J. [IBM Research – T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2015-06-08

    III–V nanoscale devices were monolithically integrated on silicon-on-insulator (SOI) substrates by template-assisted selective epitaxy (TASE) using metal organic chemical vapor deposition. Single crystal III–V (InAs, InGaAs, GaAs) nanostructures, such as nanowires, nanostructures containing constrictions, and cross junctions, as well as 3D stacked nanowires were directly obtained by epitaxial filling of lithographically defined oxide templates. The benefit of TASE is exemplified by the straightforward fabrication of nanoscale Hall structures as well as multiple gate field effect transistors (MuG-FETs) grown co-planar to the SOI layer. Hall measurements on InAs nanowire cross junctions revealed an electron mobility of 5400 cm{sup 2}/V s, while the alongside fabricated InAs MuG-FETs with ten 55 nm wide, 23 nm thick, and 390 nm long channels exhibit an on current of 660 μA/μm and a peak transconductance of 1.0 mS/μm at V{sub DS} = 0.5 V. These results demonstrate TASE as a promising fabrication approach for heterogeneous material integration on Si.

  16. Complex wound management in ventricular assist device (VAD) patients: the role of aggressive debridement and vascularized soft tissue coverage.

    Science.gov (United States)

    Nelson, Jonas A; Shaked, Oren; Fischer, John P; Mirzabeigi, Michael N; Jandali, Shareef; Kovach, Stephen J; Low, David W; Acker, Michael A; Kanchwala, Suhail K

    2014-12-01

    Infections and complex wounds after ventricular assist device (VAD) placement can result in significant morbidity and mortality. The purpose of this study was to evaluate complex wound management in the VAD patient, and to describe a treatment protocol for these challenging and potentially mortal complications. A retrospective study was performed to examine all patients who underwent continuous flow, second-generation VAD placement at the Hospital of the University of Pennsylvania between March 2008 and April 2013. Overall, 150 VADs were placed, with 12 (8%) patients requiring 15 operative interventions by the plastic surgery services. The most common indication for operative intervention was a complicated wound with VAD exposure (5/12, 41.7%). All patients underwent aggressive operative debridement, and 11/12 (92%) underwent vascularized soft tissue coverage. Flaps commonly utilized included rectus abdominus myocutaneous (n = 4), rectus abdominus muscle (n = 4), pectoralis major (n = 3), and omentum (n = 3). Three patients experienced complications which required a return to the operating room, including 1 flap loss, 1 hematoma, and 1 wound dehiscence requiring further soft tissue coverage. Salvage was achieved, yet a 50% mortality rate in follow-up was noted. Complex wound management in VAD patients can be achieved with aggressive debridement and vascularized soft tissue coverage, most commonly utilizing well-vascularized rectus abdominus muscle or omental flaps. Plastic surgeons should be familiar with the armamentarium at their disposal when approaching these challenging cases as VAD wound complications stand to become an increasingly prevalent issue.

  17. Experimental study on the Reynolds and viscous shear stress of bileaflet mechanical heart valves in a pneumatic ventricular assist device.

    Science.gov (United States)

    Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2009-01-01

    Our group is currently developing a pneumatic ventricular assist device (PVAD). In general, the major causes of hemolysis in a pulsatile VAD are cavitation, and Reynolds shear stress (RSS) in the mechanical heart valve (MHV). In a previous study, we investigated MHV cavitation. To select the optimal bileaflet valve for our PVAD, in the current study, we investigated RSS and viscous shear stress (VSS) downstream of three different types of commercial bileaflet valves by means of 2D particle image velocimetry (PIV). To carry out flow visualization inside the blood pump and near the valve, we designed a model pump with the same configuration as that of our PVAD. Three types of bileaflet valves (i.e., the ATS valve, the St. Jude valve, and the Sorin Bicarbon valve) were mounted at the aortic position of the model pump, and flow was visualized according to the PIV method. The maximum flow velocity and RSS of the Sorin Bicarbon valve were lower than those of the other two bileaflet valves. The maximum VSS was only 1% of the maximum RSS. Thus, the effect of VSS on blood cell trauma was neglected. The Sorin Bicarbon valve exhibited relatively low levels of RSS, and was therefore considered to be the best valve for our PVAD among the three valves tested.

  18. Interaction of the cardiovascular system with an implanted rotary assist device: simulation study with a refined computer model.

    Science.gov (United States)

    Vollkron, Michael; Schima, Heinrich; Huber, Leopold; Wieselthaler, Georg

    2002-04-01

    In recent years, implanted rotary pumps have achieved the level of extended clinical application including complete mobilization and physical exercise of the recipients. A computer model was developed to study the interaction between a continuous-flow pump and the recovering cardiovascular system, the effects of changing pre- and afterloads, and the possibilities for indirect estimation of hemodynamic parameters and pump control. A numerical model of the cardiovascular system using Matlab Simulink simulation software was established. Data of circulatory system modules were derived from patients, our own in vitro and in vivo experiments, and the literature. Special care was taken to simulate properly the dynamic pressure-volume characteristics of both left and right ventricle, the Frank-Starling behavior, and the impedance of the proximal vessels. Excellent correlation with measured data was achieved including pressure and flow patterns within the time domain, response to varying loads, and effects of previously observed pressure-flow hysteresis in rotary pumps. Potential energy, external work, pressure-volume area, and other derived heart work parameters could be calculated. The model offers the possibility to perform parameter variations to study the effects of changing patient condition and therapy and to display them with three-dimensional graphics (demonstrated with the effects on right ventricular work and efficiency). The presented model gives an improved understanding of the interaction between the pump and both ventricles. It can be used for the investigation of various clinical and control questions in normal and pathological conditions of the left ventricular assist device recipient.

  19. Left ventricular assist device support with a centrifugal pump for 2 months in a 5-kg child.

    Science.gov (United States)

    Inoue, Takafumi; Nishimura, Takashi; Murakami, Arata; Itatani, Keiichi; Takaoka, Tetsuhiro; Kitahori, Kazuo; Umeki, Akihide; Takezoe, Toshiko; Kashiwa, Koichi; Kyo, Shunei; Ono, Minoru

    2011-09-01

    The mid-term and long-term results of left ventricular assist device (LVAD) implantation for small children are still unsatisfactory. There have been few reports of LVAD implantation for more than a month in children weighing under 5 kg. We report the case of a 4-month-old female infant who survived for 2 months after being diagnosed with dilated cardiomyopathy (DCM) with extracorporeal centrifugal pump support. In recent years, although pumps designed for small children have been introduced and are used as a bridge to transplantation or recovery, mid-term or long-term mechanical support for small children with heart failure is still difficult. We managed to successfully provide support for a low-body-weight child with a centrifugal pump over a mid-term period. We achieved acceptable control of thrombosis, but eventually the infant died of sepsis. Autopsy revealed no prominent thrombosis in the perfusion cannula, drainage cannula, the pump, or the left ventricle. This is the first case report of LVAD support with the centrifugal pump, ROTAFLOW(®) (Maquet, Rastatt, Germany), for 2 months in a child weighing under 5 kg. Our method may potentially save severe heart failure children who need mid-term LVAD support.

  20. Flow visualization of a monoleaflet and bileaflet mechanical heart valve in a pneumatic ventricular assist device using a PIV system.

    Science.gov (United States)

    Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2010-01-01

    Our group is developing a new type of pulsatile pneumatic ventricular assist device (PVAD) that uses the Medtronic Hall tilting disc valve (M-H valve). Although tilting disc valves have good washout effect inside the blood pump, they are no longer in common clinical use and may be difficult to obtain in the future. To investigate the stability of the Sorin Bicarbon valve (S-B valve) in our PVAD, we constructed a model pump made of an acrylic resin with the same configuration as our PVAD and attempted to compare the flow visualization upstream and downstream of the outlet position valve between the M-H valve and the S-B valve using a particle image velocimetry (PIV) method. The outlet S-B valve had faster closure than the M-H valve. The maximum flow velocity was greater than with the M-H valve. The maximum Reynolds shear stress (RSS) of the M-H valve reached 150 N/m(2) and that of the S-B valve reached 300 N/m(2) upstream during the end-systolic and early-diastolic phases. In both valves, the maximum RSS upstream of the valve was higher than downstream of the valve because of the regurgitation flow during valve closure. In addition, the maximum viscous shear stress reached above 2 N/m(2), which occupied only about 1%-1.5% of the maximum RSS.

  1. Evaluation of Right Ventricular Function in the Management of Patients Referred for Left Ventricular Assist Device Therapy.

    Science.gov (United States)

    Cameli, M; Sparla, S; Focardi, M; Righini, F M; Solari, M; Alvino, F; Lisi, M; D'Ascenzi, F; Bernazzali, S; Tsioulpas, C; Sassi, C; Dokollari, A; Sani, G; Maccherini, M; Mondillo, S

    2015-09-01

    Speckle tracking echocardiography analysis (STE) has recently allowed an in-depth analysis of right ventricular (RV) performance. The aim of the study was to observe RV function by STE in patients with advanced heart failure before and after left ventricular assist device (LVAD) implantation. A transthoracic echocardiogram was performed in 19 patients referred for LVAD implant at baseline and with serial echocardiograms after LVAD implantation (Jarvik 2000). All echocardiographic images were analyzed off line by an independent operator to calculate with STE the RV free wall longitudinal strain (RVLS). All the patients, except 4, showed a progressive increase of RVLS after LVAD implant. However, 4 patients, who presented the lowest RVLS values at baseline, presented a further RV failure in the postoperative. The value of -11% represented the empirical preoperative cutoff able to identify patients at greater risk of postimplant RV failure. RV myocardial deformation may have important clinical implications for the selection and management of LVAD patients. It can be used to evaluate RV function before LVAD implantation, to drive decisional strategy regarding the management of this type of patients, and after LVAD implant for the follow-up. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Left ventricular assist device unloading effects on myocardial structure and function: current status of the field and call for action

    Science.gov (United States)

    Drakos, Stavros G.; Kfoury, Abdallah G.; Selzman, Craig H.; Verma, Divya Ratan; Nanas, John N.; Li, Dean Y.; Stehlik, Josef

    2013-01-01

    Purpose of review Myocardial remodeling driven by excess pressure and volume load is believed to be responsible for the vicious cycle of progressive myocardial dysfunction in chronic heart failure. Left ventricular assist devices (LVADs), by providing significant volume and pressure unloading, allow a reversal of stress-related compensatory responses of the overloaded myocardium. Herein, we summarize and integrate insights from studies which investigated how LVAD unloading influences the structure and function of the failing human heart. Recent findings Recent investigations have described the impact of LVAD unloading on key structural features of cardiac remodeling – cardiomyocyte hypertrophy, fibrosis, microvasculature changes, adrenergic pathways and sympathetic innervation. The effects of LVAD unloading on myocardial function, electrophysiologic properties and arrhythmias have also been generating significant interest. We also review information describing the extent and sustainability of the LVAD-induced myocardial recovery, the important advances in understanding of the pathophysiology of heart failure derived from such studies, and the implications of these findings for the development of new therapeutic strategies. Special emphasis is given to the great variety of fundamental questions at the basic, translational and clinical levels that remain unanswered and to specific investigational strategies aimed at advancing the field. Summary Structural and functional reverse remodeling associated with LVADs continues to inspire innovative research. The ultimate goal of these investigations is to achieve sustained recovery of the failing human heart. PMID:21451407

  3. First Evidence of Cardiac Stem Cells From the Left Ventricular Apical Tip in Patients With Left Ventricular Assist Device Implantation.

    Science.gov (United States)

    Cameli, M; Righini, F M; Sparla, S; Tacchini, D; Dokollari, A; Sassi, C G; Di Tommaso, C; Curci, V; Censini, S; Incampo, E; Cassano, F; Droandi, G; Bernazzali, S; Focardi, M; Ietta, F; Sartiani, L; Romagnoli, R; Marotta, G; Mugelli, A; Paulesu, L; Sani, G; Tanganelli, P; Maccherini, M; Mondillo, S

    2016-03-01

    Recent studies have challenged the dogma that the adult heart is a postmitotic organ and raise the possibility of the existence of resident cardiac stem cells (CSCs). Our study aimed to explore if these CSCs are present in the "ventricular tip" obtained during left ventricular assist device (LVAD) implantation from patients with end-stage heart failure (HF) and the relationship with LV dysfunctional area extent. Four consecutive patients with ischemic cardiomyopathy and end-stage HF submitted to LVAD implantation were studied. The explanted "ventricular tip" was used as a sample of apical myocardial tissue for the pathological examination. Patients underwent clinical and echocardiographic examination, both standard transthoracic echocardiography (TTE) and speckle tracking echocardiography (STE), before LVAD implantation. All patients presented severe apical dysfunction, with apical akinesis/diskinesis and very low levels of apical longitudinal strain (-3.5 ± 2.9%). Despite this, the presence of CSCs was demonstrated in pathological myocardial samples of "ventricular tip" in all 4 of the patients. It was found to be a mean of 6 c-kit cells in 10 fields magnification 40×. Cardiac stem cells can be identified in the LV apical segment of patients who have undergone LVAD implantation despite LV apical fibrosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Mitral Valve Regurgitation with a Rotary Left Ventricular Assist Device: The Haemodynamic Effect of Inlet Cannulation Site and Speed Modulation.

    Science.gov (United States)

    Gregory, Shaun D; Stevens, Michael C; Wu, Eric L; Pauls, Jo P; Kleinheyer, Matthias; Fraser, John F

    2016-09-01

    Mitral valve regurgitation (MVR) is common in patients receiving left ventricular assist device (LVAD) support, however the haemodynamic effect of MVR is not entirely clear. This study evaluated the haemodynamic effect of MVR with LVAD support and the influence of inflow cannulation site and LVAD speed modulation. Left atrial (LAC) and ventricular (LVC) cannulation was evaluated in a mock circulation loop with no, mild, moderate and severe MVR with constant speed and speed modulation (±600 RPM) modes. The use of an LVAD relieved pulmonary congestion during severe MVR, by reducing left atrial pressure from 20.5 to 10.8 (LAC) and 11.5 (LVC) mmHg. However, LAC resulted in decreased left ventricular stroke work (-0.08 J), ejection fraction (-7.9%) and higher MVR volume (+12.7 mL) and pump speed (+100 RPM) compared to LVC. This suggests that LVC, in addition to reducing MVR severity, also improves ventricular washout over LAC. LVAD speed modulation in synchrony with ventricular systole reduced MVR volume and increased ejection fraction with LAC and LVC, thus demonstrating the potential benefits of this mode, despite a reduction in cardiac output.

  5. Constrictive Pericarditis in the Presence of Remaining Remnants of a Left Ventricular Assist Device in a Heart Transplanted Patient

    Directory of Open Access Journals (Sweden)

    R. Rivinius

    2015-01-01

    Full Text Available Constrictive pericarditis (CP is a severe subform of pericarditis with various causes and clinical findings. Here, we present the unique case of CP in the presence of remaining remnants of a left ventricular assist device (LVAD in a heart transplanted patient. A 63-year-old man presented at the Heidelberg Heart Center outpatient clinic with progressive dyspnea, fatigue, and loss of physical capacity. Heart transplantation (HTX was performed at another heart center four years ago and postoperative clinical course was unremarkable so far. Pharmacological cardiac magnetic resonance imaging (MRI stress test was performed to exclude coronary ischemia. The test was negative but, accidentally, a foreign body located in the epicardial adipose tissue was found. The foreign body was identified as the inflow pump connection of an LVAD which was left behind after HTX. Echocardiography and cardiac catheterization confirmed the diagnosis of CP. Surgical removal was performed and the epicardial tubular structure with a diameter of 30 mm was carefully removed accompanied by pericardiectomy. No postoperative complications occurred and the patient recovered uneventfully with a rapid improvement of symptoms. On follow-up 3 and 6 months later, the patient reported about a stable clinical course with improved physical capacity and absence of dyspnea.

  6. Hemodynamic benefit of multiple programmable pacing configurations in patients with biventricular pacemakers.

    Science.gov (United States)

    Balasundaram, Ramprakash; Rao, Hygriv B; Sridevi, C; Somaraju, B; Singh, Balbir; Calambur, Narasimhan

    2009-03-01

    Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure. However, one-third of the patients fail to improve with this therapy. Stimulation with different left ventricular stimulation (LVS) configurations has been used to prevent diaphragmatic capture and to decrease the capture thresholds. We evaluated the hemodynamic effects of different LVS configurations using echocardiography. Recipients of CRT systems capable of multiple LVS configurations were studied. Biventricular capture was confirmed for each polarity and echocardiographic measurements were made. The atrioventricular and interventricular delays were optimized and kept constant during the study. The cardiac output (CO), myocardial performance index (MPI), and severity of mitral regurgitation (MR) were recorded for all LVS configurations and compared for the best and the worst configurations, determined by CO. We studied 10 men and four women, 55 +/- 13 years of age on average. The CO and MPI changed significantly by changing the LVS configurations. The difference in CO ranged from 0.3 to 1.5 L, and seven patients (50%) showed > or =20% difference in CO between best and worst LVS configurations. Severity of MR decreased by > or =1 grade in nine patients, while in two patients MR worsened despite improvement in CO. Changing the LVS configuration changes hemodynamic function in some CRT system recipients.