WorldWideScience

Sample records for system catheter model

  1. 21 CFR 870.1290 - Steerable catheter control system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Steerable catheter control system. 870.1290... catheter control system. (a) Identification. A steerable catheter control system is a device that is connected to the proximal end of a steerable guide wire that controls the motion of the steerable catheter...

  2. Open versus closed IV infusion systems: a state based model to predict risk of catheter associated blood stream infections

    Science.gov (United States)

    Barnett, Adrian G; Rosenthal, Victor D

    2011-01-01

    Objectives To quantify the change in risk of central line associated blood stream infection (CLABSI) following the introduction of a closed infusion container in intensive care units (ICUs) in two Latin American cities. Design A state-space model was used to describe the flow of admissions through the ICU. This approach correctly treats infection as a time-dependent covariate. Results A closed system reduced the risk of CLABSI. The hazard ratios for the closed versus open container were between 0.15 and 0.31 (p valuesclosed system reduced the number of infections, costs and deaths. Conclusions The data reveal costs are saved and health benefits gained from fewer cases of CLABSI after adoption of a closed infusion system. Information is required on the costs of implementing the closed system widely in these settings. PMID:22021881

  3. Generation of a central nervous system catheter-associated infection in mice with Staphylococcus epidermidis.

    Science.gov (United States)

    Snowden, Jessica N

    2014-01-01

    Animal models are valuable tools for investigating the in vivo pathogenesis of Staphylococcus epidermidis infections. Here, we present the procedure for generating a central nervous system catheter-associated infection in a mouse, to model the central nervous system shunt infections that frequently complicate the treatment of hydrocephalus in humans. This model uses stereotactic guidance to place silicone catheters, pre-coated with S. epidermidis, into the lateral ventricles of mice. This results in a catheter-associated infection in the brain, with concomitant illness and inflammation. This animal model is a valuable tool for evaluating the pathogenesis of bacterial infection in the central nervous system, the immune response to these infections and potential treatment options.

  4. A system for visualization and automatic placement of the endoclamp balloon catheter

    Science.gov (United States)

    Furtado, Hugo; Stüdeli, Thomas; Sette, Mauro; Samset, Eigil; Gersak, Borut

    2010-02-01

    The European research network "Augmented Reality in Surgery" (ARIS*ER) developed a system that supports minimally invasive cardiac surgery based on augmented reality (AR) technology. The system supports the surgical team during aortic endoclamping where a balloon catheter has to be positioned and kept in place within the aorta. The presented system addresses the two biggest difficulties of the task: lack of visualization and difficulty in maneuvering the catheter. The system was developed using a user centered design methodology with medical doctors, engineers and human factor specialists equally involved in all the development steps. The system was implemented using the AR framework "Studierstube" developed at TU Graz and can be used to visualize in real-time the position of the balloon catheter inside the aorta. The spatial position of the catheter is measured by a magnetic tracking system and superimposed on a 3D model of the patient's thorax. The alignment is made with a rigid registration algorithm. Together with a user defined target, the spatial position data drives an actuator which adjusts the position of the catheter in the initial placement and corrects migrations during the surgery. Two user studies with a silicon phantom show promising results regarding usefulness of the system: the users perform the placement tasks faster and more accurately than with the current restricted visual support. Animal studies also provided a first indication that the system brings additional value in the real clinical setting. This work represents a major step towards safer and simpler minimally invasive cardiac surgery.

  5. Nephrologists Hate the Dialysis Catheters: A Systemic Review of Dialysis Catheter Associated Infective Endocarditis

    Directory of Open Access Journals (Sweden)

    Kalyana C. Janga

    2017-01-01

    Full Text Available A 53-year-old Egyptian female with end stage renal disease, one month after start of hemodialysis via an internal jugular catheter, presented with fever and shortness of breath. She developed desquamating vesiculobullous lesions, widespread on her body. She was in profound septic shock and broad spectrum antibiotics were started with appropriate fluid replenishment. An echocardiogram revealed bulky leaflets of the mitral valve with a highly mobile vegetation about 2.3 cm long attached to the anterior leaflet. CT scan of the chest, abdomen, and pelvis showed bilateral pleural effusions in the chest, with triangular opacities in the lungs suggestive of infarcts. There was splenomegaly with triangular hypodensities consistent with splenic infarcts. Blood cultures repeatedly grew Candida albicans. Despite parenteral antifungal therapy, the patient deteriorated over the course of 5 days. She died due to a subsequent cardiac arrest. Systemic review of literature revealed that the rate of infection varies amongst the various types of accesses, and it is well documented that AV fistulas have a much less rate of infection in comparison to temporary catheters. All dialysis units should strive to make a multidisciplinary effort to have a referral process early on, for access creation, and to avoid catheters associated morbidity.

  6. [Recording of ventricular pressure by conventional catheter manometer systems. Efficiency of several combinations of conventional catheters, modern transducers and catheter-flush systems (author's transl)].

    Science.gov (United States)

    Hellige, G

    1976-01-01

    The experimentally in vitro determined dynamic response characteristics of 38 catheter manometer systems were uniform in the worst case to 5 c.p.s. and optimally to 26 c.p.s. Accordingly, some systems are only satisfactory for ordinary pressure recording in cardiac rest, while better systems record dp/dt correct up to moderate inotropic stimulation of the heart. In the frequency range of uniform response (amplitude error less +/- 5%) the phase distortion is also negligible. In clinical application the investigator is often restricted to special type of cardiac catheter. In this case a low compliant transducer yields superior results. In all examined systems the combination with MSD 10 transducers is best, whereas the combination with P 23 Db transducers leads to minimal results. An inadequate system for recording ventricular pressure pulses leads in most cases to overestimations of dp/dtmax. The use of low frequency pass filters to attenuate higher frequency artefacts is, under clinical conditions, not suitable for extending the range of uniform frequency response. The dynamic response of 14 catheter manometer systems with two types of continuous self flush units was determined. The use of the P 37 flush unit in combination with small internal diameter catheters leads to serious error in ordinary pressure recording, due to amplitude distortion of the lower harmonics. The frequency response characteristics of the combination of an Intraflow flush system and MSD 10 transducer was similar to the non-flushing P 23 Db transducer feature.

  7. Thulium fiber laser recanalization of occluded ventricular catheters in an ex vivo tissue model

    Science.gov (United States)

    Hutchens, Thomas C.; Gonzalez, David A.; Hardy, Luke A.; McLanahan, C. Scott; Fried, Nathaniel M.

    2017-04-01

    Hydrocephalus is a chronic medical condition that occurs in individuals who are unable to reabsorb cerebrospinal fluid (CSF) created within the ventricles of the brain. Treatment requires excess CSF to be diverted from the ventricles to another part of the body, where it can be returned to the vascular system via a shunt system beginning with a catheter within the ventricle. Catheter failures due to occlusion by brain tissues commonly occur and require surgical replacement of the catheter. In this preliminary study, minimally invasive clearance of occlusions is explored using an experimental thulium fiber laser (TFL), with comparison to a conventional holmium: yttrium aluminium garnet (YAG) laser. The TFL utilizes smaller optical fibers (450-μm OD), providing critical extra cross-sectional space within the 1.2-mm-inner-diameter ventricular catheter for simultaneous application of an endoscope for image guidance and a saline irrigation tube for visibility and safety. TFL ablation rates using 100-μm core fiber, 33-mJ pulse energy, 500-μs pulse duration, and 20- to 200-Hz pulse rates were compared to holmium laser using a 270-μm core fiber, 325-mJ, 300-μs, and 10 Hz. A tissue occluded catheter model was prepared using coagulated egg white within clear silicone tubing. An optimal TFL pulse rate of 50 Hz was determined, with an ablation rate of 150 μm/s and temperature rise outside the catheter of ˜10°C. High-speed camera images were used to explore the mechanism for removal of occlusions. Image guidance using a miniature, 0.7-mm outer diameter, 10,000 pixel endoscope was explored to improve procedure safety. With further development, simultaneous application of TFL with small fibers, miniature endoscope for image guidance, and irrigation tube for removal of tissue debris may provide a safe, efficient, and minimally invasive method of clearing occluded catheters in the treatment of hydrocephalus.

  8. [A new port catheter system of aluminum oxide ceramics].

    Science.gov (United States)

    Haindl, H; Schmoll, E; Willmann, G

    1995-03-01

    Implantable port catheter systems are becoming increasingly important, as they often permit out-patient treatment for many indications that would otherwise require hospitalization. Moreover, they also increase the safety/reliability of infusion therapy in critical inpatients. For a variety of reasons, the materials used so far, i.e. steel, titanium and various plastics have not been completely satisfactory. The main disadvantage of metallic systems is the formation of artefacts in tomographic images, while the shortcomings of plastics are mechanical, e.g. chip formation and early membrane failure. Against this background, a port catheter system made of alumina ceramic, which is largely free of the disadvantages of the other materials, was developed. The expected advantages in terms of complication rate and radiological artefacts, were fully confirmed by the evaluation of 160 monitored patients.

  9. Study on Acoustic Catheter of Boiler Tube Leakage Monitoring Systems

    Science.gov (United States)

    Lv, Yongxing; Feng, Qiang

    Boiler tube leakage is the major reason of affecting the safe operation of the unit now, there are 3 methods of the "four tube" leakage detection: Traditional method, filtering method and acoustic spectrum analysis, acoustic spectrum analysis is the common method, but this method have low sensitivity and the sensor damage easily. Therewith, designed the special acoustic catheter with acoustic resonance cavity type, proved by experiments, the acoustic catheter with acoustic resonance cavity type can enhance leakage sound, can accurately extract leakage signals, has high sensitivity, and can avoid the effect of sensor by fire and hot-gas when the furnace is in positive pressure situation, reduce the installation and maintenance costs of the boiler tube leakage monitor system.

  10. Stabilization of a percutaneously implanted port catheter system for hepatic artery chemotherapy infusion

    International Nuclear Information System (INIS)

    Shindoh, Noboru; Ozaki, Yutaka; Kyogoku, Shinsuke; Yamana, Daigo; Sumi, Yukiharu; Katayama, Hitoshi

    1999-01-01

    A port catheter system for hepatic artery infusion chemotherapy was implanted percutaneously via the left subclavian artery in 41 patients for treatment of unresectable liver metastases. The catheter tip was inserted into the gastroduodenal artery (GDA), the end hole was occluded with a guidewire fragment, and a side-hole for infusion was positioned at the bifurcation of the proper hepatic artery and the GDA. The GDA was embolized with steel coils around the infusion catheter tip via a transfemoral catheter. This procedure is designed to reduce the incidence of hepatic artery occlusion and infusion catheter dislocation.

  11. Multiple Coaxial Catheter System for Reliable Access in Interventional Stroke Therapy

    International Nuclear Information System (INIS)

    Kulcsar, Zsolt; Yilmaz, Hasan; Bonvin, Christophe; Lovblad, Karl O.; Ruefenacht, Daniel A.

    2010-01-01

    In some patients with acute cerebral vessel occlusion, navigating mechanical thrombectomy systems is difficult due to tortuous anatomy of the aortic arch, carotid arteries, or vertebral arteries. Our purpose was to describe a multiple coaxial catheter system used for mechanical revascularization that helps navigation and manipulations in tortuous vessels. A triple or quadruple coaxial catheter system was built in 28 consecutive cases presenting with acute ischemic stroke. All cases were treated by mechanical thrombectomy with the Penumbra System. In cases of unsuccessful thrombo-aspiration, additional thrombolysis or angioplasty with stent placement was used for improving recanalization. The catheter system consisted of an outermost 8-Fr and an intermediate 6-Fr guiding catheter, containing the inner Penumbra reperfusion catheters. The largest, 4.1-Fr, reperfusion catheter was navigated over a Prowler Select Plus microcatheter. The catheter system provided access to reach the cerebral lesions and provided stability for the mechanically demanding manipulations of thromboaspiration and stent navigation in all cases. Apart from their mechanical role, the specific parts of the system could also provide access to different types of interventions, like carotid stenting through the 8-Fr guiding catheter and intracranial stenting and thrombolysis through the Prowler Select Plus microcatheter. In this series, there were no complications related to the catheter system. In conclusion, building up a triple or quadruple coaxial system proved to be safe and efficient in our experience for the mechanical thrombectomy treatment of acute ischemic stroke.

  12. An ovine model of cerebral catheter venography for implantation of an endovascular neural interface.

    Science.gov (United States)

    Oxley, Thomas James; Opie, Nicholas Lachlan; Rind, Gil Simon; Liyanage, Kishan; John, Sam Emmanuel; Ronayne, Stephen; McDonald, Alan James; Dornom, Anthony; Lovell, Timothy John Haynes; Mitchell, Peter John; Bennett, Iwan; Bauquier, Sebastien; Warne, Leon Norris; Steward, Chris; Grayden, David Bruce; Desmond, Patricia; Davis, Stephen M; O'Brien, Terence John; May, Clive N

    2018-04-01

    OBJECTIVE Neural interface technology may enable the development of novel therapies to treat neurological conditions, including motor prostheses for spinal cord injury. Intracranial neural interfaces currently require a craniotomy to achieve implantation and may result in chronic tissue inflammation. Novel approaches are required that achieve less invasive implantation methods while maintaining high spatial resolution. An endovascular stent electrode array avoids direct brain trauma and is able to record electrocorticography in local cortical tissue from within the venous vasculature. The motor area in sheep runs in a parasagittal plane immediately adjacent to the superior sagittal sinus (SSS). The authors aimed to develop a sheep model of cerebral venography that would enable validation of an endovascular neural interface. METHODS Cerebral catheter venography was performed in 39 consecutive sheep. Contrast-enhanced MRI of the brain was performed on 13 animals. Multiple telescoping coaxial catheter systems were assessed to determine the largest wide-bore delivery catheter that could be delivered into the anterior SSS. Measurements of SSS diameter and distance from the motor area were taken. The location of the motor area was determined in relation to lateral and superior projections of digital subtraction venography images and confirmed on MRI. RESULTS The venous pathway from the common jugular vein (7.4 mm) to the anterior SSS (1.2 mm) was technically challenging to selectively catheterize. The SSS coursed immediately adjacent to the motor cortex (catheters was associated with longer procedure times and higher complication rates. A 4-Fr catheter (internal lumen diameter 1.1 mm) was successful in accessing the SSS in 100% of cases with no associated complications. Complications included procedure-related venous dissection in two major areas: the torcular herophili, and the anterior formation of the SSS. The bifurcation of the cruciate sulcal veins with the SSS was

  13. Convective Leakage Makes Heparin Locking of Central Venous Catheters Ineffective Within Seconds: Experimental Measurements in a Model Superior Vena Cava.

    Science.gov (United States)

    Barbour, Michael C; McGah, Patrick M; Ng, Chin H; Clark, Alicia M; Gow, Kenneth W; Aliseda, Alberto

    2015-01-01

    Central venous catheters (CVCs), placed in the superior vena cava (SVC) for hemodialysis or chemotherapy, are routinely filled while not in use with heparin, an anticoagulant, to maintain patency and prevent thrombus formation at the catheter tip. The heparin-locking procedure, however, places the patient at risk for systemic bleeding, as heparin is known to leak from the catheter into the blood stream. We provide evidence from detailed in vitro experiments that shows the driving mechanism behind heparin leakage to be convective-diffusive transport due to the pulsatile flow surrounding the catheter. This novel mechanism is supported by experimental planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) measurements of flow velocity and heparin transport from a CVC placed inside a model SVC inside a pulsatile flow loop. The results predict an initial, fast (<10 s), convection-dominated phase that rapidly depletes the concentration of heparin in the near-tip region, the region of the catheter with side holes. This is followed by a slow, diffusion-limited phase inside the catheter lumen, where the concentration is still high, that is insufficient at replenishing the lost heparin concentration in the near-tip region. The results presented here, which are consistent with previous in vivo estimates of 24 hour leakage rates, predict that the concentration of heparin in the near-tip region is essentially zero for the majority of the interdialytic phase, rendering the heparin locking procedure ineffective.

  14. Pseudo-Rigid-Body Model and Kinematic Analysis of MRI-Actuated Catheters.

    Science.gov (United States)

    Greigarn, Tipakorn; Çavuşoğlu, M Cenk

    2015-05-01

    This paper presents a kinematic study of a pseudorigid-body model (PRBM) of MRI-compatible, magnetically actuated, steerable catheters. It includes a derivation of a mathematical model of the PRBM of the catheter, singularity studies of the model, and a new manipulability measure. While the forward kinematics of the model presented here is applicable to PRBMs for other applications, actuation method is unique to the particular design. Hence, a careful study of singularities and manipulability of the model is required. The singularities are studied from the underlying equations of motion with intuitive interpretations. The proposed manipulability measure is a generalization of the inverse condition number manipulability measure of robotic manipulators. While the PRBM is an approximation of the flexible catheter, kinematic studies of the PRBM still provide some insight into feasibility and limitations of the catheter, which is beneficial to the design and motion planning of the catheter.

  15. A Deep-Learning System for Fully-Automated Peripherally Inserted Central Catheter (PICC) Tip Detection.

    Science.gov (United States)

    Lee, Hyunkwang; Mansouri, Mohammad; Tajmir, Shahein; Lev, Michael H; Do, Synho

    2017-10-05

    A peripherally inserted central catheter (PICC) is a thin catheter that is inserted via arm veins and threaded near the heart, providing intravenous access. The final catheter tip position is always confirmed on a chest radiograph (CXR) immediately after insertion since malpositioned PICCs can cause potentially life-threatening complications. Although radiologists interpret PICC tip location with high accuracy, delays in interpretation can be significant. In this study, we proposed a fully-automated, deep-learning system with a cascading segmentation AI system containing two fully convolutional neural networks for detecting a PICC line and its tip location. A preprocessing module performed image quality and dimension normalization, and a post-processing module found the PICC tip accurately by pruning false positives. Our best model, trained on 400 training cases and selectively tuned on 50 validation cases, obtained absolute distances from ground truth with a mean of 3.10 mm, a standard deviation of 2.03 mm, and a root mean squares error (RMSE) of 3.71 mm on 150 held-out test cases. This system could help speed confirmation of PICC position and further be generalized to include other types of vascular access and therapeutic support devices.

  16. In Vitro Urethra Model to Characterize The Frictional Properties of Urinary Catheters

    DEFF Research Database (Denmark)

    Røn, Troels; Lee, Seunghwan

    2016-01-01

    conformal sliding contacts with the catheter and high relevance to clinical catherization. With the proposed urethra model assembled in texture analyzer, the lubricity of catheters lubricated in different modes was tested. In comparison with conventional pin-on-disk tribometry, the coefficients of friction......, frictional properties of tubular devices such as catheters, endoscopes, and angioplasty balloons are particularly challenging to characterize because of non-standard shape and contact configuration. In this study, we propose that fabrication of in vitro urethra model with castable elastomers can provide...... of sliding contacts with the urethra model with unlubricated and lubricated catheters were determined. Impact of the improved bio-relevance of friction testing methods on the evaluation of various catheter materials and surface modification methods is discussed in detail....

  17. Effectiveness of a Drill-assisted Intraosseous Catheter versus Manual Intraosseous Catheter by Resident Physicians in a Swine Model

    Directory of Open Access Journals (Sweden)

    Hafner, John William

    2013-11-01

    Full Text Available Introduction: Our objective was to compare the effectiveness, speed, and complication rate of the traditional manually placed intraosseous (IO catheter to a mechanical drill-assisted IO catheter by emergency medicine (EM resident physicians in a training environment. Methods: Twenty-one EM residents participated in a randomized prospective crossover experiment placing 2 intraosseous needles (Cook® Intraosseous Needle, Cook Medical, Bloomington, IN; and EZ-IO® Infusion System, Vidacare, San Antonio, TX. IO needles were placed in anesthetized mixed breed swine (mass range: 25 kg to 27.2 kg. The order of IO placement and puncture location (proximal tibia or distal femur were randomly assigned. IO placement time was recorded from skin puncture until the operator felt they had achieved successful placement. We used 3 verification criteria: aspiration of marrow blood, easy infusion of 10 mL saline mixed with methylene blue, and lack of stained soft tissue extravasation. Successful placement was defined as meeting 2 out of the 3 predetermined criteria. We surveyed participants regarding previous IO experience, device preferences, and comfort levels using multiple choice, Likert scale, and visual analog scale (VAS questions. IO completion times, VAS, and mean Likert scales were compared using Student’s t-test and success rates were compared using Fisher’s exact test with p<0.05 considered significant.Results: Drill-assisted IO needle placement was faster than manually placed IO needle placement (3.66 vs. 33.57 seconds; p=0.01. Success rates were 100% with the drill-assisted IO needle and 76.2% with the manual IO needle (p=0.04. The most common complication of the manual IO insertion was a bent needle (33.3% of attempts. Participants surveyed preferred the drill-assisted IO insertion more than the manual IO insertion (p<0.0001 and felt the drill-assisted IO was easier to place (p<0.0001.Conclusion: In an experimental swine model, drill-assisted IO

  18. Tissue adhesion to bioactive glass-coated silicone tubing in a rat model of peritoneal dialysis catheters and catheter tunnels.

    Science.gov (United States)

    Ross, Edward A; Batich, Christopher D; Clapp, William L; Sallustio, Judith E; Lee, Nadeen C

    2003-02-01

    Silicone peritoneal dialysis catheters do not develop tissue ingrowth, lack a mechanical barrier to periluminal bacterial migration and need cuffs for anchorage. We hypothesized that a bioactive glass coating composed of silicon, calcium, sodium and phosphorous oxides would cause a beneficial tissue reaction causing catheter adhesion, and tested this in a rat model. A hexane solvent-based method of coating silicone tubes with Bioglass powder was used, which maintained flexibility, and then the ultrastructure was confirmed with scanning electron microscopy (EM). Segments 2.5 cm were implanted subcutaneously in 8 Sprague-Dawley rats, with uncoated tubes as a contralateral control, and histology was done at 2, 4 and 6 weeks, including special stains and EM. The uncoated segments grossly had no adherence to surrounding tissue, and were physically separate from a thin fibrous capsule of approximately 50 micro width. Trichrome stains demonstrated the capsule was rich in collagen. There was minimal adjacent tissue reaction. In contrast, the coated tubes were palpably fixed to the soft tissues, and sections demonstrated an adjacent prominent layer of macrophages and multinucleated giant cells. Small numbers of lymphocytes were noted. This cellular reaction increased over the 6-week implant duration, and was also associated with neovascularization of the tissue adjacent to the segments (33 vessels in coated vs. 20 in controls per x 200 field, P tubing by promoting adhesion by collagen and cell proliferation, and are promising for future studies of peritoneal dialysis catheters.

  19. Navigation of guidewires and catheters in the body during intervention procedures : A review of computer-based models

    NARCIS (Netherlands)

    Sharei Amarghan, H.; Alderliesten, Tanja; van den Dobbelsteen, J.J.; Dankelman, J.

    2018-01-01

    Guidewires and catheters are used during minimally invasive interventional procedures to traverse in vascular system and access the desired position. Computer models are increasingly being used to predict the behavior of these instruments. This information can be used to choose the right

  20. Systematic review and meta-analysis: reminder systems to reduce catheter-associated urinary tract infections and urinary catheter use in hospitalized patients.

    Science.gov (United States)

    Meddings, Jennifer; Rogers, Mary A M; Macy, Michelle; Saint, Sanjay

    2010-09-01

    Prolonged catheterization is the primary risk factor for catheter-associated urinary tract infection (CAUTI). Reminder systems are interventions used to prompt the removal of unnecessary urinary catheters. To summarize the effect of urinary catheter reminder systems on the rate of CAUTI, urinary catheter use, and the need for recatheterization, we performed a systematic review and meta-analysis. Studies were identified in MEDLINE, the Cochrane Library, Biosis, the Web of Science, EMBASE, and CINAHL through August 2008. Only interventional studies that used reminders to physicians or nurses that a urinary catheter was in use or stop orders to prompt catheter removal in hospitalized adults were included. A total of 6679 citations were identified; 118 articles were reviewed, and 14 articles met the selection criteria. The rate of CAUTI (episodes per 1000 catheter-days) was reduced by 52% (P SMD) in the duration of catheterization was -1.11 overall (P = 070), including a statistically significant decrease in studies that used a stop order (SMD, -0.30; P = .001) but not in those that used a reminder (SMD, -1.54; P = .071). Recatheterization rates were similar in control and intervention groups. Urinary catheter reminders and stop orders appear to reduce the rate of CAUTI and should be strongly considered to enhance the safety of hospitalized patients.

  1. Optimization of Catheter Ablation of Atrial Fibrillation: Insights Gained from Clinically-Derived Computer Models

    Directory of Open Access Journals (Sweden)

    Jichao Zhao

    2015-05-01

    Full Text Available Atrial fibrillation (AF is the most common heart rhythm disturbance, and its treatment is an increasing economic burden on the health care system. Despite recent intense clinical, experimental and basic research activity, the treatment of AF with current antiarrhythmic drugs and catheter/surgical therapies remains limited. Radiofrequency catheter ablation (RFCA is widely used to treat patients with AF. Current clinical ablation strategies are largely based on atrial anatomy and/or substrate detected using different approaches, and they vary from one clinical center to another. The nature of clinical ablation leads to ambiguity regarding the optimal patient personalization of the therapy partly due to the fact that each empirical configuration of ablation lines made in a patient is irreversible during one ablation procedure. To investigate optimized ablation lesion line sets, in silico experimentation is an ideal solution. 3D computer models give us a unique advantage to plan and assess the effectiveness of different ablation strategies before and during RFCA. Reliability of in silico assessment is ensured by inclusion of accurate 3D atrial geometry, realistic fiber orientation, accurate fibrosis distribution and cellular kinetics; however, most of this detailed information in the current computer models is extrapolated from animal models and not from the human heart. The predictive power of computer models will increase as they are validated with human experimental and clinical data. To make the most from a computer model, one needs to develop 3D computer models based on the same functionally and structurally mapped intact human atria with high spatial resolution. The purpose of this review paper is to summarize recent developments in clinically-derived computer models and the clinical insights they provide for catheter ablation.

  2. A system to use electromagnetic tracking for the quality assurance of brachytherapy catheter digitization

    International Nuclear Information System (INIS)

    Damato, Antonio L.; Viswanathan, Akila N.; Don, Sarah M.; Hansen, Jorgen L.; Cormack, Robert A.

    2014-01-01

    Purpose: To investigate the use of a system using electromagnetic tracking (EMT), post-processing and an error-detection algorithm for detecting errors and resolving uncertainties in high-dose-rate brachytherapy catheter digitization for treatment planning. Methods: EMT was used to localize 15 catheters inserted into a phantom using a stepwise acquisition technique. Five distinct acquisition experiments were performed. Noise associated with the acquisition was calculated. The dwell location configuration was extracted from the EMT data. A CT scan of the phantom was performed, and five distinct catheter digitization sessions were performed. No a priori registration of the CT scan coordinate system with the EMT coordinate system was performed. CT-based digitization was automatically extracted from the brachytherapy plan DICOM files (CT), and rigid registration was performed between EMT and CT dwell positions. EMT registration error was characterized in terms of the mean and maximum distance between corresponding EMT and CT dwell positions per catheter. An algorithm for error detection and identification was presented. Three types of errors were systematically simulated: swap of two catheter numbers, partial swap of catheter number identification for parts of the catheters (mix), and catheter-tip shift. Error-detection sensitivity (number of simulated scenarios correctly identified as containing an error/number of simulated scenarios containing an error) and specificity (number of scenarios correctly identified as not containing errors/number of correct scenarios) were calculated. Catheter identification sensitivity (number of catheters correctly identified as erroneous across all scenarios/number of erroneous catheters across all scenarios) and specificity (number of catheters correctly identified as correct across all scenarios/number of correct catheters across all scenarios) were calculated. The mean detected and identified shift was calculated. Results: The

  3. Development of Remote-Type Haptic Catheter Sensor System using Piezoelectric Transducer

    Science.gov (United States)

    Haruta, Mineyuki; Murayama, Yoshinobu; Omata, Sadao

    This study describes the development of Remote-Type Haptic Catheter Sensor System which enables the mechanical property evaluation of a blood vessel. This system consists of a feedback circuit and a piezoelectric ultrasound transducer, and is operated based on a phase shift method so that the entire system oscillates at its inherent resonance frequency. Ultrasound reflected by the blood vessel makes a phase shift of the resonance system depending on the acoustic impedance of the reflector. The phase shift is then measured as a change in resonance frequency of the system; therefore, the detection resolution is highly improved. The correlation between the acoustic impedance and the resonance frequency change of the sensor system was demonstrated using silicone rubbers, metals and actual blood vessels from a pig. The performance of the sensor was also examined using vessel shaped phantom model. Finally, the discussion surveys a possibility of the novel sensor system in an application for intra vascular diagnosis.

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography uses a catheter, x-ray ... are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive medical test ...

  5. Endovascular brain intervention and mapping in a dog experimental model using magnetically-guided micro-catheter technology.

    Science.gov (United States)

    Kara, Tomas; Leinveber, Pavel; Vlasin, Michal; Jurak, Pavel; Novak, Miroslav; Novak, Zdenek; Chrastina, Jan; Czechowicz, Krzysztof; Belehrad, Milos; Asirvatham, Samuel J

    2014-06-01

    Despite the substantial progress that has been achieved in interventional cardiology and cardiac electrophysiology, endovascular intervention for the diagnosis and treatment of central nervous system (CNS) disorders such as stroke, epilepsy and CNS malignancy is still limited, particularly due to highly tortuous nature of the cerebral arterial and venous system. Existing interventional devices and techniques enable only limited and complicated access especially into intra-cerebral vessels. The aim of this study was to develop a micro-catheter magnetically-guided technology specifically designed for endovascular intervention and mapping in deep CNS vascular structures. Mapping of electrical brain activity was performed via the venous system on an animal dog model with the support of the NIOBE II system. A novel micro-catheter specially designed for endovascular interventions in the CNS, with the support of the NIOBE II technology, was able to reach safely deep intra-cerebral venous structures and map the electrical activity there. Such structures are not currently accessible using standard catheters. This is the first study demonstrating successful use of a new micro-catheter in combination with NIOBE II technology for endovascular intervention in the brain.

  6. Accurate model-based segmentation of gynecologic brachytherapy catheter collections in MRI-images.

    Science.gov (United States)

    Mastmeyer, Andre; Pernelle, Guillaume; Ma, Ruibin; Barber, Lauren; Kapur, Tina

    2017-12-01

    The gynecological cancer mortality rate, including cervical, ovarian, vaginal and vulvar cancers, is more than 20,000 annually in the US alone. In many countries, including the US, external-beam radiotherapy followed by high dose rate brachytherapy is the standard-of-care. The superior ability of MR to visualize soft tissue has led to an increase in its usage in planning and delivering brachytherapy treatment. A technical challenge associated with the use of MRI imaging for brachytherapy, in contrast to that of CT imaging, is the visualization of catheters that are used to place radiation sources into cancerous tissue. We describe here a precise, accurate method for achieving catheter segmentation and visualization. The algorithm, with the assistance of manually provided tip locations, performs segmentation using image-features, and is guided by a catheter-specific, estimated mechanical model. A final quality control step removes outliers or conflicting catheter trajectories. The mean Hausdorff error on a 54 patient, 760 catheter reference database was 1.49  mm; 51 of the outliers deviated more than two catheter widths (3.4  mm) from the gold standard, corresponding to catheter identification accuracy of 93% in a Syed-Neblett template. In a multi-user simulation experiment for evaluating RMS precision by simulating varying manually-provided superior tip positions, 3σ maximum errors were 2.44  mm. The average segmentation time for a single catheter was 3 s on a standard PC. The segmentation time, accuracy and precision, are promising indicators of the value of this method for clinical translation of MR-guidance in gynecologic brachytherapy and other catheter-based interventional procedures. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Estimating input original waveform from catheter-manometer system output waveform--an experimental study with pulmonary artery catheter.

    Science.gov (United States)

    Saito, Satoru; Shimada, Masato; Kinefuchi, Yoshio; Suzuki, Toshiyasu

    2006-04-20

    The present study was performed to investigate the precision of and problems in arithmetic operations for synthesis/estimation of the input waveform from the output waveform of a pulmonary artery catheter (PAC) manometer system, by imposing arterial pressure waveform as an input pressure waveform. When a PAC manometer system is regarded as a second-order system, the input waveform can be synthesized/estimated from the output waveform by determining the natural frequency (fn), and damping coefficient (ζ) of the said system. The precision of synthesis/estimation diminished with the decreasing fn of the PAC manometer system. An attempt was thus made to explore the cause of the reduction in precision of estimation due to decreases in fn by constructing a second-order system equivalent circuit and a differentiation arithmetic circuit on the circuit simulator. The results demonstrated that correct synthesis/estimation of input waveform were attainable only when the set of fn and ζ for the arithmetic circuit coincided with that of the PAC manometer system. Decreases in fn correspond to such instances where the PAC manometer system can no longer be regarded as a second-order system, thus nullifying the measured fn and ζ. This accounts for the reduction in precision.

  8. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    International Nuclear Information System (INIS)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-01-01

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora ® Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators

  9. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca [Département de physique, de génie physique et d’optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Binnekamp, Dirk [Integrated Clinical Solutions and Marketing, Philips Healthcare, Veenpluis 4-6, Best 5680 DA (Netherlands)

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  10. Catheter Angiography

    Medline Plus

    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography uses a ... few millimeters) in the skin where the catheter can be inserted into an artery. The catheter is ...

  11. Theoretical modelling, experimental studies and clinical simulations of urethral cooling catheters for use during prostate thermal therapy

    International Nuclear Information System (INIS)

    Davidson, Sean R H; Sherar, Michael D

    2003-01-01

    Urethral cooling catheters are used to prevent thermal damage to the urethra during thermal therapy of the prostate. Quantification of a catheter's heat transfer characteristics is necessary for prediction of the catheter's influence on the temperature and thermal dose distribution in periurethral tissue. Two cooling catheters with different designs were examined: the Dornier Urowave catheter and a prototype device from BSD Medical Corp. A convection coefficient, h, was used to characterize the cooling ability of each catheter. The value of the convection coefficient (h = 330 W m -2 deg C -1 for the Dornier catheter, h = 160 W m -2 deg C -1 for the BSD device) was obtained by comparing temperatures measured in a tissue-equivalent phantom material to temperatures predicted by a finite element method simulation of the phantom experiments. The coefficient was found to be insensitive to the rate of coolant flow inside the catheter between 40 and 120 ml min -1 . The convection coefficient method for modelling urethral catheters was incorporated into simulations of microwave heating of the prostate. Results from these simulations indicate that the Dornier device is significantly more effective than the BSD catheter at cooling the tissue surrounding the urethra

  12. Tracking the position and rotational orientation of a catheter using a transmit array system.

    Science.gov (United States)

    Celik, Haydar; Mahcicek, Davut I; Senel, Oytun K; Wright, Graham A; Atalar, Ergin

    2013-04-01

    A new method for detecting the rotational orientation and tracking the position of an inductively coupled radio frequency (ICRF) coil using a transmit array system is proposed. The method employs a conventional body birdcage coil, but the quadrature hybrid is eliminated so that the two excitation channels can be used separately. The transmit array system provides RF excitations such that the body birdcage coil creates linearly polarized and changing RF pulses instead of a conventional rotational forward-polarized excitation. The receive coils and their operations are not modified. Inductively coupled RF coils are constructed on catheters for detecting rotational orientation and for tracking purposes. Signals from the anatomy and from tissue close to the ICRF coil are different due to the new RF excitation scheme: the ICRF coil can be separated from the anatomy in real time, and after doing so, a color-coded image is reconstructed. More importantly, this novel method enables a real-time calculation of the absolute rotational orientation of an ICRF coil constructed on a catheter. Modified FLASH and TrueFISP sequences are used for the experiments. The acquired images from this technique show the feasibility of different applications, such as catheter tracking. Furthermore, applications where knowledge of the rotational orientation of the catheter is important, such as magnetic resonance-guided endoluminal-focused ultrasound, RF ablation, side-looking optical imaging, and catheters with side ports for needles, become feasible with this method.

  13. Development of a New Coaxial Balloon Catheter System for Balloon-Occluded Retrograde Transvenous Obliteration (B-RTO)

    International Nuclear Information System (INIS)

    Tanoue, Shuichi; Kiyosue, Hiro; Matsumoto, Shunro; Hori, Yuzo; Okahara, Mika; Kashiwagi, Junji; Mori, Hiromu

    2006-01-01

    Purpose. To develop a new coaxial balloon catheter system and evaluate its clinical feasibility for balloon-occluded retrograde transvenous obliteration (B-RTO). Methods. A coaxial balloon catheter system was constructed with 9 Fr guiding balloon catheter and 5 Fr balloon catheter. A 5 Fr catheter has a high flexibility and can be coaxially inserted into the guiding catheter in advance. The catheter balloons are made of natural rubber and can be inflated to 2 cm (guiding) and 1 cm (5 Fr) maximum diameter. Between July 2003 and April 2005, 8 consecutive patients (6 men, 2 women; age range 33-72 years, mean age 55.5 years) underwent B-RTO using the balloon catheter system. Five percent ethanolamine oleate iopamidol (EOI) was used as sclerosing agent. The procedures, including maneuverability of the catheter, amount of injected sclerosing agent, necessity for coil embolization of collateral draining veins, and initial clinical results, were evaluated retrospectively. The occlusion rate was assessed by postcontrast CT within 2 weeks after B-RTO. Results. The balloon catheter could be advanced into the proximal potion of the gastrorenal shunt beyond the collateral draining vein in all cases. The amount of injected EOI ranged from 3 to 34 ml. Coil embolization of the collateral draining vein was required in 2 cases. Complete obliteration of gastric varices on initial follow-up CT was obtained in 7 cases. The remaining case required re-treatment that resulted in complete obstruction of the varices after the second B-RTO. No procedure-related complications were observed. Conclusion. B-RTO using the new coaxial balloon catheter is feasible. Gastric varices can be treated more simply by using this catheter system

  14. Frequency response evaluation of radial artery catheter-manometer systems: sinusoidal frequency analysis versus flush method.

    Science.gov (United States)

    Schwid, H A

    1988-07-01

    It is well recognized that catheter-manometer systems significantly distort direct radial artery pressure measurements. Sinusoidal frequency analysis and the flush method of assessing the degree of distortion caused by the monitoring system were compared to determine whether these two methods agree in the estimation of natural frequency and damping coefficient. The frequency response of 30 radial artery catheter-manometer systems used for intensive-care unit patients was measured by the flush method and sinusoidal frequency analysis. The monitoring system consisted of a 20-gauge cannula, 150-cm pressure tubing, two plastic stopcocks, a continuous infusion device with fast flush valve, an American Edwards dome, a Hewlett-Packard quartz transducer, and a Hewlett-Packard blood pressure amplifier. Sinusoidal frequency analysis demonstrated second-order underdamped response for all 30 catheter-manometer systems. No secondary resonance peaks were observed up to a frequency of 200 Hz. The measured frequency response demonstrated that the average catheter-manometer system in use in our intensive care unit would cause significant distortion of the radial artery pressure, with the mean natural frequency (fn) of 14.7 +/- 3.7 Hz and the mean damping coefficient (zeta) of 0.24 +/- 0.07. Although the 30 monitoring systems had identical configurations and visible bubbles were carefully removed, a wide range of frequency responses was found (fn = 10.2 to 25.3; zeta = 0.15 to 0.44).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump.

    Science.gov (United States)

    Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit

    2017-06-09

    Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

  16. Presence of air in the hepatic portal system in association with umbilical venous catheter malposition

    Directory of Open Access Journals (Sweden)

    Beatriz Regina Alvares

    2014-01-01

    Full Text Available The authors report a case of umbilical venous catheter malposition with air in the portal venous system in a preterm neonate. Initially, the hypothesis of necrotizing enterocolitis was considered, but the newborn progressed with no finding of disease and the air disappeared at follow-up radiography. The differential diagnosis of such a finding can avoid unnecessary clinical treatments.

  17. Optimal Guiding Catheter Length for Endovascular Coiling of Intracranial Aneurysms in Anterior Circulation in Era of Flourishing Distal Access System.

    Science.gov (United States)

    Jia, Zhen Yu; Lee, Sang Hun; Kim, Young Eun; Choi, Joon Ho; Hwang, Sun Moon; Lee, Ga Young; Youn, Jin Ho; Lee, Deok Hee

    2017-09-01

    To determine the minimum required guiding catheter length for embolization of various intracranial aneurysms in anterior circulation and to analyze the effect of various patient factors on the required catheter length and potential interaction with its stability. From December 2016 to March 2017, 90 patients with 93 anterior circulation aneurysms were enrolled. Three types of guiding catheters (Envoy, Envoy DA, and Envoy DA XB; Codman Neurovascular, Raynham, MA, USA) were used. We measured the in-the-body length of the catheter and checked the catheter tip location in the carotid artery. We analyzed factors affecting the in-the-body length and stability of the guiding catheter system. The average (±standard deviation) in-the-body length of the catheter was 84.2±5.9 cm. The length was significantly longer in men (89.1±5.6 vs. 82.1±4.6 cm, Pguiding catheter was 84 cm on average for elective anterior-circulation aneurysm embolization. The length increased in men older than 65 years with a more tortuous arch. We could reach a higher position with distal access catheters with little difference in the stability once we reached the target location.

  18. Catheter Angiography

    Medline Plus

    Full Text Available ... using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin ... called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes ...

  19. Catheter Angiography

    Medline Plus

    Full Text Available ... x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin plastic ... superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of a catheter makes it ...

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... risks? What are the limitations of Catheter Angiography? What is Catheter Angiography? Angiography is a minimally invasive ... of ionizing radiation ( x-rays ). top of page What are some common uses of the procedure? Catheter ...

  1. Catheter Angiography

    Medline Plus

    Full Text Available ... use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter ... use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An ...

  2. Catheter Angiography

    Medline Plus

    Full Text Available ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example ...

  3. Urinary catheters

    Science.gov (United States)

    ... indwelling catheter, clean the area where the catheter exits your body and the catheter itself with soap ... DO, urologist with the Michigan Institute of Urology, West Bloomfield, MI. Review provided by VeriMed Healthcare Network. ...

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... resonance imaging (MRI) In catheter angiography, a thin plastic tube, called a catheter , is inserted into an ... The catheter used in angiography is a long plastic tube about as thick as a strand of ...

  5. An assembly-type master-slave catheter and guidewire driving system for vascular intervention.

    Science.gov (United States)

    Cha, Hyo-Jeong; Yi, Byung-Ju; Won, Jong Yun

    2017-01-01

    Current vascular intervention inevitably exposes a large amount of X-ray to both an operator and a patient during the procedure. The purpose of this study is to propose a new catheter driving system which assists the operator in aspects of less X-ray exposure and convenient user interface. For this, an assembly-type 4-degree-of-freedom master-slave system was designed and tested to verify the efficiency. First, current vascular intervention procedures are analyzed to develop a new robotic procedure that enables us to use conventional vascular intervention devices such as catheter and guidewire which are commercially available in the market. Some parts of the slave robot which contact the devices were designed to be easily assembled and dissembled from the main body of the slave robot for sterilization. A master robot is compactly designed to conduct insertion and rotational motion and is able to switch from the guidewire driving mode to the catheter driving mode or vice versa. A phantom resembling the human arteries was developed, and the master-slave robotic system is tested using the phantom. The contact force of the guidewire tip according to the shape of the arteries is measured and reflected to the user through the master robot during the phantom experiment. This system can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. Also, benefits of the proposed robot system are low cost by employing currently available devices and easy human interface.

  6. 3D Printed Modeling of the Mitral Valve for Catheter-Based Structural Interventions.

    Science.gov (United States)

    Vukicevic, Marija; Puperi, Daniel S; Jane Grande-Allen, K; Little, Stephen H

    2017-02-01

    As catheter-based structural heart interventions become increasingly complex, the ability to effectively model patient-specific valve geometry as well as the potential interaction of an implanted device within that geometry will become increasingly important. Our aim with this investigation was to combine the technologies of high-spatial resolution cardiac imaging, image processing software, and fused multi-material 3D printing, to demonstrate that patient-specific models of the mitral valve apparatus could be created to facilitate functional evaluation of novel trans-catheter mitral valve repair strategies. Clinical 3D transesophageal echocardiography and computed tomography images were acquired for three patients being evaluated for a catheter-based mitral valve repair. Target anatomies were identified, segmented and reconstructed into 3D patient-specific digital models. For each patient, the mitral valve apparatus was digitally reconstructed from a single or fused imaging data set. Using multi-material 3D printing methods, patient-specific anatomic replicas of the mitral valve were created. 3D print materials were selected based on the mechanical testing of elastomeric TangoPlus materials (Stratasys, Eden Prairie, Minnesota, USA) and were compared to freshly harvested porcine leaflet tissue. The effective bending modulus of healthy porcine MV tissue was significantly less than the bending modulus of TangoPlus (p  0.95). We have demonstrated that patient-specific mitral valve models can be reconstructed from multi-modality imaging datasets and fabricated using the multi-material 3D printing technology and we provide two examples to show how catheter-based repair devices could be evaluated within specific patient 3D printed valve geometry. However, we recognize that the use of 3D printed models for the development of new therapies, or for specific procedural training has yet to be defined.

  7. Catheter Angiography

    Medline Plus

    Full Text Available ... Z Catheter Angiography Catheter angiography uses a catheter, x-ray imaging guidance and an injection of contrast material ... vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging ( ...

  8. Pulmonary vein isolation using the Rhythmia mapping system: Verification of intracardiac signals using the Orion mini-basket catheter.

    Science.gov (United States)

    Anter, Elad; Tschabrunn, Cory M; Contreras-Valdes, Fernando M; Li, Jianqing; Josephson, Mark E

    2015-09-01

    During pulmonary vein isolation (PVI), a circular lasso catheter is positioned at the junction between the left atrium (LA) and the pulmonary vein (PV) to confirm PVI. The Rhythmia mapping system uses the Orion mini-basket catheter with 64 electrodes instead of the lasso catheter. However, its feasibility to determine PVI has not been studied. The purpose of this study was to compare signals between the mini-basket and lasso catheters at the LA-PV junction. In 12 patients undergoing PVI using Rhythmia, the mini-basket and lasso catheters were placed simultaneously at the LA-PV junction for baseline and post-PVI signal assessment. Pacing from both catheters was performed to examine the presence of exit block. At baseline, recordings of LA and PV potentials were concordant in all PVs. However, after PVI, concordance between the catheters was only 68%. Discordance in all cases resulted from loss of PV potentials on the lasso catheter with persistence of PV potentials on the mini-basket catheter. In 9 of 13 PVs (69%), these potentials represented true PV potentials that were exclusively recorded with the smaller and closely spaced mini-basket electrodes. In the other 4 PVs (31%), these potentials originated from neighboring structures and resulted in underestimation of PVI. The use of the mini-basket catheter alone is sufficient to determine PVI. While it improves recording of PV potentials after incomplete ablation, it is also associated with frequent recording of "PV-like" potentials originating from neighboring structures. In these cases, pacing maneuvers are helpful to determine PVI and avoid excessive ablation. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  9. Automated Pointing of Cardiac Imaging Catheters.

    Science.gov (United States)

    Loschak, Paul M; Brattain, Laura J; Howe, Robert D

    2013-12-31

    Intracardiac echocardiography (ICE) catheters enable high-quality ultrasound imaging within the heart, but their use in guiding procedures is limited due to the difficulty of manually pointing them at structures of interest. This paper presents the design and testing of a catheter steering model for robotic control of commercial ICE catheters. The four actuated degrees of freedom (4-DOF) are two catheter handle knobs to produce bi-directional bending in combination with rotation and translation of the handle. An extra degree of freedom in the system allows the imaging plane (dependent on orientation) to be directed at an object of interest. A closed form solution for forward and inverse kinematics enables control of the catheter tip position and the imaging plane orientation. The proposed algorithms were validated with a robotic test bed using electromagnetic sensor tracking of the catheter tip. The ability to automatically acquire imaging targets in the heart may improve the efficiency and effectiveness of intracardiac catheter interventions by allowing visualization of soft tissue structures that are not visible using standard fluoroscopic guidance. Although the system has been developed and tested for manipulating ICE catheters, the methods described here are applicable to any long thin tendon-driven tool (with single or bi-directional bending) requiring accurate tip position and orientation control.

  10. The fast flush test: evaluation in radial artery catheter-manometer systems.

    Science.gov (United States)

    Sheahan, N F; Tuohy, B; Kirkham, R; Coakley, D; Malone, J

    1991-08-01

    The 'fast flush test' is commonly used to determine the dynamic response of catheter-manometer systems in vivo. We compared the fast flush test with an established bench top test in vitro. The results of the two tests were compared in fifteen underdamped radical artery catheter-manometer systems. There were significant differences between the results, (P less than 0.001 for both resonant frequency and damping factor), and the variance of estimates within measurement systems was significantly greater in the case of the fast flush test (P less than 0.05 and P less than 0.005 for resonant frequency and damping factor respectively). Nevertheless, the differences between the tests were small by comparison with the errors associated with either test; in addition there was a significant linear correlation between the results of the two tests (r = 0.91, P less than 0.001 and r = 0.85, P less than 0.001 for resonant frequency and damping factor respectively). In the in vitro situation, therefore, the fast flush test provides a crude estimate of the dynamic parameters of underdamped catheter-manometer systems.

  11. Robotic ablation of atrial fibrillation with a new remote catheter system.

    Science.gov (United States)

    Wutzler, Alexander; Wolber, Thomas; Parwani, Abdul Shokor; Huemer, Martin; Attanasio, Philipp; Blaschke, Florian; Haegeli, Laurent; Haverkamp, Wilhelm; Duru, Firat; Boldt, Leif-Hendrik

    2014-09-01

    Pulmonary vein isolation (PVI) is widely established as a curative treatment option for atrial fibrillation (AF). A wide range of techniques to improve catheter manipulation and steerability has been developed over the past years. A new remote catheter system (RCS) has recently become available (Amigo Remote Catheter System, Catheter Robotics, Budd Lake, NJ, USA). Here, we present a dual-center study on the RCS for left atrial mapping and PVI in patients with paroxysmal AF compared to a control group undergoing conventional PVI. One hundred nineteen patients who underwent PVI for paroxysmal AF were studied. Forty patients underwent PVI with the use of the RCS. Seventy-nine patients, who underwent conventional PVI, served as control group. Procedural data were compared between the two groups. PVI was achieved in all patients. In the RCS group compared to standard ablation group, there were no significant differences in procedure duration (159.1 ± 45.4 vs. 146 ± 30.1 min, p = 0.19), total energy delivery (78,146.3 ± 26,992.4 vs. 87,963.9 ± 79,202.1 Ws, p = 0.57), and total fluoroscopy time (21.2 ± 8.6 vs. 23.9 ± 5.4 min, p = 0.15). Operator fluoroscopy exposure was significantly reduced in the RCS group (13.4 ± 6.1 vs. 23.9 ± 5.4 min, p < 0.001). These initial results suggest that left atrial mapping and PVI are feasible with the use of the Amigo RCS. Acute procedural efficacy is comparable to the standard approach. The use of the Amigo RCS leads to a significant reduction of operator fluoroscopy exposure.

  12. Integrated HIFU Drive System on a Chip for CMUT-Based Catheter Ablation System.

    Science.gov (United States)

    Farhanieh, Omid; Sahafi, Ali; Bardhan Roy, Rupak; Ergun, Arif Sanli; Bozkurt, Ayhan

    2017-06-01

    Conventional High Intensity Focused Ultrasound (HIFU) is a therapeutic modality which is extracorporeally administered. In applications where a relatively small HIFU lesion is required, an intravascular HIFU probe can be deployed to the ablation site. In this paper, we demonstrate the design and implementation a fully integrated HIFU drive system on a chip to be placed on a 6 Fr catheter probe. An 8-element capacitive micromachined ultrasound transducer (CMUT) ring array of 2 mm diameter has been used as the ultrasound source. The driver chip is fabricated in 0.35 μm AMS high-voltage CMOS technology and comprises eight continuous-wave (CW) high-voltage CMUT drivers (10.9 ns and 9.4 ns rise and fall times at 20 V pp output into a 15 pF), an eight-channel digital beamformer (8-12 MHz output frequency with 11.25 ° phase accuracy) and a phase locked loop with an integrated VCO as a tunable clock source (128-192 MHz). The chip occupies 1.85 × 1.8 mm 2 area including input and output (I/O) pads. When the transducer array is immersed in sunflower oil and driven by the IC with eight 20 V pp CW pulses at 10 MHz, real-time thermal images of the HIFU beam indicate that the focal temperature rises by 16.8  ° C in 11 seconds. Each HV driver consumes around 67 mW of power when driving the CMUT array at 10 MHz, which adds up to 560 mW for the whole chip. FEM based analysis reveals that the outer surface temperature of the catheter is expected to remain below the 42  ° C tissue damage limit during therapy.

  13. Evaluation of dynamic response of catheter-manometer systems for pulmonary arterial pressure.

    Science.gov (United States)

    Kinefuchi, Y; Suzuki, T; Takiguchi, M; Yamasaki, Y; Yamamoto, M

    1994-10-01

    To quantitatively evaluate the waveform distortions observed through a catheter-manometer system, the tolerance range of amplitude errors and that of phase errors are defined as both within +/- 5%, and the frequency bandwidth was calculated where the frequency characteristics of amplitude and those of phase difference satisfy the two tolerance ranges by use of a second-order kinetic equation. The results were expressed by three variables, composed of the natural frequency (fn), damping coefficient (zeta), and highest frequency (fh) corresponding to the frequency bandwidth; a chart was constructed with fn on the x-axis, zeta on the y-axis, and fh as parameter. Also on the chart, the propagation delay times (td's) determined by fn, zeta, and fh were plotted. We measured the frequency characteristics of two 7-Fr Swan-Ganz catheters with lengths of 75 and 110 cm. fn's and zeta's were found to be 13.9 and 10.1 Hz and 0.23 and 0.32, respectively. Referring to this chart, the maximal fh these catheters would be able to reproduce within the tolerance ranges and the propagation td's can be predicted to be 3.2 and 2.4 Hz and 7 and 12 ms, respectively. Suppression of resonance by use of Accudynamic improved the maximal fh's to 3.9 and 2.9 Hz, respectively, but resulted in the increased td's to 14 and 19 ms due to increased zeta.

  14. In vitro, in vivo and numerical assessment of the working principle of the truCCOMS continuous cardiac output catheter system.

    Science.gov (United States)

    Claessens, T; Verwilst, P; Missant, C; Claus, P; Verdonck, P; Wouters, P; Segers, P

    2009-12-01

    The truCCOMS cardiac output monitor system provides a continuous and instantaneous measurement of cardiac output, derived from the amount of energy required for heating a filament to maintain a fixed 2 degrees C blood temperature difference between two thermistors located distally on a pulmonary artery catheter. Clinical studies, however, reported relatively poor accuracy of the cardiac output estimation, possibly due to linearly assumed power-cardiac output relationship used for calibration of the catheters. We experimentally studied the shape of the truCCOMS calibration relationship (i) in a hydraulic bench model of the right heart and (ii) in vivo intact animal model. The results showed a nonlinear relationship between the power input into the heating element and the cardiac output; which could satisfactorily be described with an exponential relationship. Comparison of the performance of the same catheters in vitro and in vivo showed that the in vitro determined calibration relationship should not be used for in vivo measurements. Finally, we also simulated the working principle of the catheter using a simplified numerical model of the blood flow and heat transfer around the catheter. The computed results also suggested a pronounced nonlinear relationship between power and cardiac output in pulsatile conditions. We conclude that the observed over- and underestimation of high- and low flows, respectively, by the current truCCOMS system is likely to arise from its linear calibration relationship. An appropriate calibration scheme accounting for the intrinsic nonlinear power-cardiac output relationship and the difference between in vitro and in vivo conditions should improve the clinical performance of the system.

  15. Catheter-based induction of renal ischemia/reperfusion in swine: description of an experimental model.

    Science.gov (United States)

    Malagrino, Pamella A; Venturini, Gabriela; Yogi, Patrícia S; Dariolli, Rafael; Padilha, Kallyandra; Kiers, Bianca; Gois, Tamiris C; da Motta-Leal-Filho, Joaquim M; Takimura, Celso K; Girardi, Adriana C C; Carnevale, Francisco C; Zeri, Ana C M; Malheiros, Denise M A C; Krieger, José E; Pereira, Alexandre C

    2014-09-01

    Several techniques to induce renal ischemia have been proposed: clamp, PVA particles, and catheter-balloon. We report the development of a controlled, single-insult model of unilateral renal ischemia/reperfusion (I/R) without contralateral nephrectomy, using a suitable model, the pig. This is a balloon-catheter-based model using a percutaneous, interventional radiology procedure. One angioplasty balloon-catheter was placed into the right renal artery and inflated for 120 min and reperfusion over 24 h. Serial serums were sampled from the inferior vena cava and urine was directly sampled from the bladder throughout the experiment, and both kidneys were excised after 24 h of reperfusion. Analyses of renal structure and function were performed by hematoxylin-eosin/periodic Acid-Schiff, serum creatinine (SCr), blood urea nitrogen (BUN), fractional excretion of ions, and glucose, SDS-PAGE analysis of urinary proteins, and serum neutrophil gelatinase-associated lipocalin (NGAL). Total nitrated protein was quantified to characterize oxidative stress. Acute tubular necrosis (ATN) was identified in every animal, but only two animals showed levels of SCr above 150% of baseline values. As expected, I/R increased SCr and BUN. Fractional sodium, potassium, chloride, and bicarbonate excretion were modulated during ischemia. Serum-nitrated proteins and NGAL had two profiles: decreased with ischemia and increased after reperfusion. This decline was associated with increased protein excretion during ischemia and early reperfusion. Altogether, these data show that the renal I/R model can be performed by percutaneous approach in the swine model. This is a suitable translational model to study new early renal ischemic biomarkers and pathophysiological mechanisms in renal ischemia. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  16. Adjuvant Hepatic Arterial Infusion Chemotherapy After Resection for Pancreatic Cancer Using Coaxial Catheter-Port System Compared with Conventional System

    International Nuclear Information System (INIS)

    Hashimoto, Aya; Tanaka, Toshihiro; Sho, Masayuki; Nishiofuku, Hideyuki; Masada, Tetsuya; Sato, Takeshi; Marugami, Nagaaki; Anai, Hiroshi; Sakaguchi, Hiroshi; Kanno, Masatoshi; Tamamoto, Tetsuro; Hasegawa, Masatoshi; Nakajima, Yoshiyuki; Kichikawa, Kimihiko

    2016-01-01

    PurposePrevious reports have shown the effectiveness of adjuvant hepatic arterial infusion chemotherapy (HAIC) in pancreatic cancer. However, percutaneous catheter placement is technically difficult after pancreatic surgery. The purpose of this study was to evaluate the feasibility and outcome of HAIC using a coaxial technique compared with conventional technique for postoperative pancreatic cancer.Materials and Methods93 consecutive patients who received percutaneous catheter-port system placement after pancreatectomy were enrolled. In 58 patients from March 2006 to August 2010 (Group A), a conventional technique with a 5-Fr indwelling catheter was used and in 35 patients from September 2010 to September 2012 (Group B), a coaxial technique with a 2.7-Fr coaxial catheter was used.ResultsThe overall technical success rates were 97.1 % in Group B and 86.2 % in Group A. In cases with arterial tortuousness and stenosis, the success rate was significantly higher in Group B (91.7 vs. 53.8 %; P = 0.046). Fluoroscopic and total procedure times were significantly shorter in Group B: 14.7 versus 26.7 min (P = 0.001) and 64.8 versus 80.7 min (P = 0.0051), respectively. No differences were seen in the complication rate. The 1 year liver metastasis rates were 9.9 % using the conventional system and 9.1 % using the coaxial system (P = 0.678). The overall median survival time was 44 months. There was no difference in the survival period between two systems (P = 0.312).ConclusionsThe coaxial technique is useful for catheter placement after pancreatectomy, achieving a high success rate and reducing fluoroscopic and procedure times, while maintaining the safety and efficacy for adjuvant HAIC in pancreatic cancer.

  17. Adjuvant Hepatic Arterial Infusion Chemotherapy After Resection for Pancreatic Cancer Using Coaxial Catheter-Port System Compared with Conventional System

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Aya; Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp [Nara Medical University, Department of Radiology (Japan); Sho, Masayuki [Nara Medical University, Department of Surgery (Japan); Nishiofuku, Hideyuki; Masada, Tetsuya; Sato, Takeshi; Marugami, Nagaaki [Nara Medical University, Department of Radiology (Japan); Anai, Hiroshi [Nara City Hospital, Department of Radiology (Japan); Sakaguchi, Hiroshi [Nara Prefectural Western Medical Center, Department of Radiology (Japan); Kanno, Masatoshi [Nara Medical University, Oncology Center (Japan); Tamamoto, Tetsuro; Hasegawa, Masatoshi [Nara Medical University, Department of Radiation Oncology (Japan); Nakajima, Yoshiyuki [Nara Medical University, Department of Surgery (Japan); Kichikawa, Kimihiko [Nara Medical University, Department of Radiology (Japan)

    2016-06-15

    PurposePrevious reports have shown the effectiveness of adjuvant hepatic arterial infusion chemotherapy (HAIC) in pancreatic cancer. However, percutaneous catheter placement is technically difficult after pancreatic surgery. The purpose of this study was to evaluate the feasibility and outcome of HAIC using a coaxial technique compared with conventional technique for postoperative pancreatic cancer.Materials and Methods93 consecutive patients who received percutaneous catheter-port system placement after pancreatectomy were enrolled. In 58 patients from March 2006 to August 2010 (Group A), a conventional technique with a 5-Fr indwelling catheter was used and in 35 patients from September 2010 to September 2012 (Group B), a coaxial technique with a 2.7-Fr coaxial catheter was used.ResultsThe overall technical success rates were 97.1 % in Group B and 86.2 % in Group A. In cases with arterial tortuousness and stenosis, the success rate was significantly higher in Group B (91.7 vs. 53.8 %; P = 0.046). Fluoroscopic and total procedure times were significantly shorter in Group B: 14.7 versus 26.7 min (P = 0.001) and 64.8 versus 80.7 min (P = 0.0051), respectively. No differences were seen in the complication rate. The 1 year liver metastasis rates were 9.9 % using the conventional system and 9.1 % using the coaxial system (P = 0.678). The overall median survival time was 44 months. There was no difference in the survival period between two systems (P = 0.312).ConclusionsThe coaxial technique is useful for catheter placement after pancreatectomy, achieving a high success rate and reducing fluoroscopic and procedure times, while maintaining the safety and efficacy for adjuvant HAIC in pancreatic cancer.

  18. Catheter Angiography

    Medline Plus

    Full Text Available ... the body for abnormalities such as aneurysms and disease such as atherosclerosis (plaque). The use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography ...

  19. Catheter Angiography

    Medline Plus

    Full Text Available ... anxiety during the procedure. The area of the groin or arm where the catheter will be inserted ... it will make the rest of the procedure pain-free. You will not feel the catheter in ...

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, ... a tumor; this is called superselective angiography. Unlike computed tomography (CT) or magnetic resonance (MR) angiography , use of ...

  1. Catheter Angiography

    Medline Plus

    Full Text Available ... it will make the rest of the procedure pain-free. You will not feel the catheter in ... nurse if you notice any bleeding, swelling or pain at the site where the catheter entered the ...

  2. Catheter Angiography

    Medline Plus

    Full Text Available ... should inform the nurse if you notice any bleeding, swelling or pain at the site where the ... Rarely, the catheter punctures the artery, causing internal bleeding. It also is possible that the catheter tip ...

  3. Catheter Angiography

    Medline Plus

    Full Text Available ... or other procedures such as chemoembolization or selective internal radiation therapy. identify dissection or splitting in the ... days. Rarely, the catheter punctures the artery, causing internal bleeding. It also is possible that the catheter ...

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... incision in the skin. Once the catheter is guided to the area being examined, a contrast material ... inserted into an artery. The catheter is then guided through the arteries to the area to be ...

  5. Catheter Angiography

    Medline Plus

    Full Text Available ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography produces very ... of a catheter makes it possible to combine diagnosis and treatment in a single procedure. An example is finding ...

  6. Intracardiac Echocardiography Guided Transeptal Catheter Injection of Microspheres for Assessment of Cerebral Microcirculation in Experimental Models

    Directory of Open Access Journals (Sweden)

    Judith Bellapart

    2013-01-01

    Full Text Available The use of microspheres for the determination of regional microvascular blood flow (RMBF has previously used different approaches. This study presents for the first time the intracardiac injection of microspheres using transeptal puncture under intracardiac echocardiography guidance. Five Merino sheep were instrumented and cardiovascularly supported according to local guidelines. Two catheter sheaths into the internal jugular vein facilitated the introduction of an intracardiac probe and transeptal catheter, respectively. Five million colour coded microspheres were injected into the left atrium via this catheter. After euthanasia the brain was used as proof of principle and the endpoint for determination of microcirculation at different time points. Homogeneous allocation of microspheres to different regions of the brain was found over time. Alternate slices from both hemispheres showed the following flow ranges: for slice 02; 0.57–1.02 mL/min/g, slice 04; 0.45–1.42 mL/min/g, slice 06; 0.35–1.87 mL/min/g, slice 08; 0.46–1.77 mL/min/g, slice 10; 0.34–1.28 mL/min/g. A mixed effect regression model demonstrated that the confidence interval did include zero suggesting that the apparent variability intra- and intersubject was not statistically significant, supporting the stability and reproducibility of the injection technique. This study demonstrates the feasibility of the transeptal injection of microspheres, showing a homogeneous distribution of blood flow through the brain unchanged over time and has established a new interventional model for the measurement of RMBF in ovine models.

  7. Reprocessing single-use cardiac catheters for interventional cardiology. A cost-minimization model for estimating potential saving at departmental scale and national level

    Directory of Open Access Journals (Sweden)

    Francesco Tessarolo

    2009-06-01

    Full Text Available

    Background: The utilization of single-use percutaneous catheters (SUDs is a common practice in interventional cardiology, but the increasing of cardiac interventions and the consequent economic load demand for assessing SUDs’ reuse. The study aimed at estimating the potential saving for Italian cardiology departments in the hypothesis that reprocessing and reuse of SUD is performed by guaranteeing safety and efficiency of the reconditioned device as high as the new marketed one.

    Methods: A cost-minimization model was applied from the perspective of the health national service. Input parameters for the model were settled by reviewing published data on technical, hygiene and functional properties of reprocessed electrophysiology (EP and percutaneous transluminal coronary angioplasty (PTCA catheters. Potential saving at department level was calculated as percentage of the actual expenditure for purchasing single-use devices. Two-ways sensitivity analysis was conducted on main cost drivers. Finally, saving at national level was estimated.

    Results: The revision of technical and safety data showed the feasibility of reprocessing and reuse of EP and PTCA catheters under determined constrains. Potential savings of 39%, and 12% were calculated at department level for EP and PTCA catheters, respectively. Sensitivity analysis showed saving was dependent primarily on departmental workload. Major variations in saving occurred in the range between one and 200 catheters per year. The cut-off between benefit and charges was also related to regeneration rate and maximum number of uses. The estimate of potential saving at national level ranged in the interval from €19.85M to €24.24M.

    Conclusions:When safety and efficiency is assured by certified reuse processing, substantial saving could be achieved both at departmental and national level contributing to optimize budget

  8. Clinical nursing of pelvic neoplasm treated with infusion chemotherapy by using an anti-reflux arterial port-catheter system

    International Nuclear Information System (INIS)

    Xing Li; Yuan Chanjuan

    2011-01-01

    Objective: To discuss the clinical nursing care for patients with pelvic neoplasm who were treated with infusion chemotherapy by using an anti-reflux arterial port-catheter system. Methods: After the implantation of an anti-reflux arterial port-catheter system was successfully completed, intra-arterial infusion chemotherapy was carried out in 17 patients with pelvic neoplasm and the infusion chemotherapy was repeated for several times. The pre-procedural clinical nursing care was well done and the technique of proper placement was well grasped. The side effects of chemotherapy drugs and complications were dealt with in time. Medical orientation at discharge time included the protection methods for port-catheter system. Results: Seventeen patients received infusion chemotherapy successfully several times (ranged from 3 to 8 times) with a scheduled regular interval time. No severe complications occurred. No catheter leakage nor obvious irritation and compression symptoms of local skin developed during infusion period. Of the 17 patients, 6 had a complete response, 9 achieved a partial response, while the remaining 2 failed to respond. Conclusion: In accordance with characteristics of infusion chemotherapy by using an anti-reflux arterial port-catheter system, the reasonable and effective nursing care is important to guarantee the achievement of a successful performance and a satisfactory therapeutic result. (authors)

  9. Design and performance evaluation of collision protection-based safety operation for a haptic robot-assisted catheter operating system.

    Science.gov (United States)

    Zhang, Linshuai; Guo, Shuxiang; Yu, Huadong; Song, Yu; Tamiya, Takashi; Hirata, Hideyuki; Ishihara, Hidenori

    2018-02-23

    The robot-assisted catheter system can increase operating distance thus preventing the exposure radiation of the surgeon to X-ray for endovascular catheterization. However, few designs have considered the collision protection between the catheter tip and the vessel wall. This paper presents a novel catheter operating system based on tissue protection to prevent vessel puncture caused by collision. The integrated haptic interface not only allows the operator to feel the real force feedback, but also combines with the newly proposed collision protection mechanism (CPM) to mitigate the collision trauma. The CPM can release the catheter quickly when the measured force exceeds a certain threshold, so as to avoid the vessel puncture. A significant advantage is that the proposed mechanism can adjust the protection threshold in real time by the current according to the actual characteristics of the blood vessel. To verify the effectiveness of the tissue protection by the system, the evaluation experiments in vitro were carried out. The results show that the further collision damage can be effectively prevented by the CPM, which implies the realization of relative safe catheterization. This research provides some insights into the functional improvements of safe and reliable robot-assisted catheter systems.

  10. Embolization of carotid-cavernous fistula using a silicone balloon and a tracker-catheter system

    International Nuclear Information System (INIS)

    Kim, Sun Yong; Cho, Kil Ho; Park, Bok Hwan

    1992-01-01

    With the recent introduction and development of the detachable balloon system, it has become the treatment of choice in the management of carotid cavernous fistulas(CCFs). But, since most delivery systems for embolization of CCF mainly depend on flow guidance for balloon delivery, in case of small fistula, pseudo aneurysm and arterialized venous collaterals, failure of balloon embolization can occur. To overcome these limitation, the authors designed and used a new versatile, steerable, and flow-guided detachable balloon system by using a Tracker catheter system with silicone or latex balloons. Using this maneuver, we could get successful fistula occlusion in 7 out of 8 patients (silicone balloon). But in one case, we had to occlude the internal carotid artery at the fistula site, proximal and distal cervical portions of the internal carotid artery. This balloon delivery system proved to provide high selectivity for fistula and relatively ease of handing

  11. Catheter-manometer system damped blood pressures detected by neural nets.

    Science.gov (United States)

    Prentza, A; Wesseling, K H

    1995-07-01

    Degraded catheter-manometer systems cause distortion of blood pressure waveforms, often leading to erroneously resonant or damped waveforms, requiring waveforms quality control. We have tried multilayer perceptron back-propagation trained neural nets of varying architecture to detect damping on sets of normal and artificially damped brachial arterial pressure waves. A second-order digital simulation of a catheter-manometer system is used to cause waveform distortion. Each beat in the waveforms is represented by an 11 parameter input vector. From a group of normotensive or (borderline) hypertensive subjects, pressure waves are used to statistically test and train the neural nets. For each patient and category 5-10 waves are available. The best neural nets correctly classify about 75-85% of the individual beats as either adequate or damped. Using a single majority vote classification per subject per damped or adequate situation, the best neural nets correctly classify at least 16 of the 18 situations in nine test subjects (binomial P = 0.001). More importantly, these neural nets can always detect damping before clinically relevant parameters such as systolic pressure and computed stroke volume are reduced by more than 2%. Neural nets seem remarkably well adapted to solving such subtle problems as detecting a slight damping of arterial pressure waves before it affects waveforms to a clinically relevant degree.

  12. Integration of a capacitive pressure sensing system into the outer catheter wall for coronary artery FFR measurements

    Science.gov (United States)

    Stam, Frank; Kuisma, Heikki; Gao, Feng; Saarilahti, Jaakko; Gomes Martins, David; Kärkkäinen, Anu; Marrinan, Brendan; Pintal, Sebastian

    2017-05-01

    The deadliest disease in the world is coronary artery disease (CAD), which is related to a narrowing (stenosis) of blood vessels due to fatty deposits, plaque, on the arterial walls. The level of stenosis in the coronary arteries can be assessed by Fractional Flow Reserve (FFR) measurements. This involves determining the ratio between the maximum achievable blood flow in a diseased coronary artery and the theoretical maximum flow in a normal coronary artery. The blood flow is represented by a pressure drop, thus a pressure wire or pressure sensor integrated in a catheter can be used to calculate the ratio between the coronary pressure distal to the stenosis and the normal coronary pressure. A 2 Fr (0.67mm) outer diameter catheter was used, which required a high level of microelectronics miniaturisation to fit a pressure sensing system into the outer wall. The catheter has an eccentric guidewire lumen with a diameter of 0.43mm, which implies that the thickest catheter wall section provides less than 210 microns height for flex assembly integration consisting of two dies, a capacitive MEMS pressure sensor and an ASIC. In order to achieve this a very thin circuit flex was used, and the two chips were thinned down to 75 microns and flip chip mounted face down on the flex. Many challenges were involved in obtaining a flex layout that could wrap into a small tube without getting the dies damaged, while still maintaining enough flexibility for the catheter to navigate the arterial system.

  13. Catheter Angiography

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Catheter Angiography Catheter angiography ...

  14. Catheter Angiography

    Medline Plus

    Full Text Available ... imaging technologies and, in most cases, a contrast material injection is needed to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters computed tomography (CT) magnetic resonance imaging (MRI) In catheter angiography, a thin ...

  15. Catheter Angiography

    Medline Plus

    Full Text Available ... injected through the catheter and reaches the blood vessels being studied, several sets of x-rays are taken. Then the catheter is removed and the incision site is closed by applying pressure on the area for approximately 10 to 20 ...

  16. Catheter Angiography

    Medline Plus

    Full Text Available ... is injected through the catheter and reaches the blood vessels being studied, several sets of x-rays are taken. Then the catheter is removed and the incision site is closed by applying pressure on the area for approximately 10 to 20 ...

  17. Urinary catheter - infants

    Science.gov (United States)

    Bladder catheter - infants; Foley catheter - infants; Urinary catheter - neonatal ... A urinary catheter is a small, soft tube placed in the bladder. This article addresses urinary catheters in babies. WHY IS ...

  18. Effect of External Pressure and Catheter Gauge on Flow Rate, Kinetic Energy, and Endothelial Injury During Intravenous Fluid Administration in a Rabbit Model.

    Science.gov (United States)

    Hu, Mei-Hua; Chan, Wei-Hung; Chen, Yao-Chang; Cherng, Chen-Hwan; Lin, Chih-Kung; Tsai, Chien-Sung; Chou, Yu-Ching; Huang, Go-Shine

    2016-01-01

    The effects of intravenous (IV) catheter gauge and pressurization of IV fluid (IVF) bags on fluid flow rate have been studied. However, the pressure needed to achieve a flow rate equivalent to that of a 16 gauge (G) catheter through smaller G catheters and the potential for endothelial damage from the increased kinetic energy produced by higher pressurization are unclear. Constant pressure on an IVF bag was maintained by an automatic adjustable pneumatic pressure regulator of our own design. Fluids running through 16 G, 18 G, 20 G, and 22 G catheters were assessed while using IV bag pressurization to achieve the flow rate equivalent to that of a 16 G catheter. We assessed flow rates, kinetic energy, and flow injury to rabbit inferior vena cava endothelium. By applying sufficient external constant pressure to an IVF bag, all fluids could be run through smaller (G) catheters at the flow rate in a 16 G catheter. However, the kinetic energy increased significantly as the catheter G increased. Damage to the venous endothelium was negligible or minimal/patchy cell loss. We designed a new rapid infusion system, which provides a constant pressure that compresses the fluid volume until it is free from visible residual fluid. When large-bore venous access cannot be obtained, multiple smaller catheters, external pressure, or both should be considered. However, caution should be exercised when fluid pressurized to reach a flow rate equivalent to that in a 16 G catheter is run through a smaller G catheter because of the profound increase in kinetic energy that can lead to venous endothelium injury.

  19. FACTORS AND COMPLICATIONS AFFECTING CATHETER AND TECHNIQUE SURVIVAL WITH PERMANENT SINGLE-LUMEN DIALYSIS CATHETERS

    NARCIS (Netherlands)

    DEMEESTER, J; VANHOLDER, R; DEROOSE, J; RINGOIR, S

    1994-01-01

    This long-term study on the outcome of permanent silicone single-lumen dialysis catheters consisted of 43 surgically inserted catheters in 33 patients. All catheters were attached to a pressure-pressure single-cannula dialysis system. Technique and catheter survival were 80 and 59% at 1 year, and 63

  20. Catheter Angiography

    Medline Plus

    Full Text Available ... machine produces a small burst of radiation that passes through the body, recording an image on photographic ... By selecting the arteries through which the catheter passes, it is possible to assess vessels in several ...

  1. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... and x-rays. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  2. Catheter Angiography

    Medline Plus

    Full Text Available ... prick when the needle is inserted into your vein for the intravenous line (IV). Injecting a local anesthetic at the site where the catheter is inserted may sting briefly, but it will ...

  3. Catheter Angiography

    Medline Plus

    Full Text Available ... examine blood vessels in key areas of the body for abnormalities such as aneurysms and disease such ... to produce pictures of blood vessels in the body. Angiography is performed using: x-rays with catheters ...

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... story about radiology? Share your patient story here Images × Image Gallery Interventional radiologist performing an angiography exam View ... ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Catheter Angiography Sponsored by Please note ...

  5. Catheter Angiography

    Medline Plus

    Full Text Available ... dose of ionizing radiation ( x-rays ). top of page What are some common uses of the procedure? Catheter ... live more than an hour away. top of page What does the equipment look like? The equipment typically ...

  6. Catheter Angiography

    Medline Plus

    Full Text Available ... the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while ... by angioplasty and placement of a stent . The degree of detail displayed by catheter angiography may not ...

  7. Catheter Angiography

    Medline Plus

    Full Text Available ... rays ). top of page What are some common uses of the procedure? Catheter angiography is used to ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  8. Catheter Angiography

    Medline Plus

    Full Text Available ... will make the rest of the procedure pain-free. You will not feel the catheter in your ... of North America, Inc. (RSNA). To help ensure current and accurate information, we do not permit copying ...

  9. Catheter Angiography

    Medline Plus

    Full Text Available ... tube, called a catheter , is inserted into an artery through a small incision in the skin. Once ... in the chest and abdomen, or in other arteries. detect atherosclerotic (plaque) disease in the carotid artery ...

  10. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a ... material injection, you should immediately inform the technologist. Women should always inform their physician or x-ray ...

  11. Catheter Angiography

    Medline Plus

    Full Text Available ... such as aneurysms and disease such as atherosclerosis (plaque). The use of a catheter makes it possible ... and abdomen, or in other arteries. detect atherosclerotic (plaque) disease in the carotid artery of the neck, ...

  12. Catheter Angiography

    Medline Plus

    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, medications you're taking and allergies, especially ... is Catheter Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical ...

  13. Catheter Angiography

    Medline Plus

    Full Text Available ... diagnosis and treatment in a single procedure. An example is finding an area of severe arterial narrowing, ... contrast material, your radiologist may advise that you take special medication for 24 hours before catheter angiography ...

  14. Catheter Angiography

    Medline Plus

    Full Text Available ... disease). evaluate obstructions of vessels. top of page How should I prepare? You should inform your physician ... as a strand of spaghetti. top of page How does the procedure work? Catheter angiography works much ...

  15. Catheter Angiography

    Medline Plus

    Full Text Available ... of page What are some common uses of the procedure? Catheter angiography is used to examine blood ... an hour away. top of page What does the equipment look like? The equipment typically used for ...

  16. Image-Guided High-Dose Rate Brachytherapy in Cervix Carcinoma Using Balloon Catheter and Belt Immobilization System.

    Science.gov (United States)

    Fan, Qiyong; Yeung, Anamaria R; Amdur, Robert; Helmig, Richard; Park, Justin; Li, Jonathan; Kahler, Darren; Liu, Chihray; Lu, Bo

    2017-06-01

    The efficacy of image-guided high-dose rate brachytherapy for cervical cancer is limited by the ineffective rectal sparing devices available commercially and the potential applicator movement. We developed a novel device using a balloon catheter and a belt immobilization system, serving for rectal dose reduction and applicator immobilization purposes, respectively. The balloon catheter is constructed by gluing a short inflatable tube to a long regular open-end catheter. Contrast agent (10) cm 3 is injected into the inflatable end, which is affixed to the tandem and ring applicator, to displace the posterior vaginal wall. The belt immobilization system consists of a specially designed bracket that can hold and fix itself to the applicator, a diaper-like Velcro fastener package used for connecting the patient's pelvis to the bracket, and a buckle that holds the fasteners to stabilize the whole system. The treatment data for 21 patients with cervical cancer using both balloon catheter and belt immobilization system were retrospectively analyzed. Computed tomography and magnetic resonance images, acquired about 30 minutes apart, were registered to evaluate the effectiveness of the immobilization system. In comparison with a virtual rectal blade, the balloon decreased the rectal point dose by 34% ± 4.2% (from 276 ± 57 to 182 ± 38 cGy), corresponding to an extra sparing distance of 7.9 ± 1.1 mm. The maximum sparing distance variation per patient is 1.4 ± 0.6 mm, indicating the high interfractional reproducibility for rectum sparing. With the immobilization system, the mean translational and rotational displacements of the applicator set are <3 mm and <1.5°, respectively, in all directions. The rectal balloon provides significant dose reduction to the rectum and it may potentially minimize patient discomfort. The immobilization system permits almost no movement of the applicator during treatment. This work has the potential to be promoted as a standardized solution

  17. Emergent embolization for control of massive hemorrhage from a splanchnic artery with a new coaxial catheter system

    International Nuclear Information System (INIS)

    Okazaki, M.; Higashihara, H.; Koganemaru, F.; Ono, H.; Fujimitsu, R.; Yamasaki, S.; Toyoshima, H.; Sato, S.; Hoashi, T.; Kimura, T.

    1992-01-01

    Emergent superselective embolization with a 3.0 F (1 mm) coaxial catheter and a steerable guidewire was performed in 27 patients with massive hemorrhage from a small-caliber splanchnic artery. Eight patients had intraperitoneal hemorrhage, 3 had hemobilia, 9 had gastric hemorrhage, and 7 had intestinal hemorrhage. Out of 27 patients, 7 had hemorrhage from a splanchnic artery pseudoaneurysm. Complete cessation of bleeding was obtained in all patients initially, but in 3 patients gastric hemorrhage recurred later. Otherwise, there was no rebleeding nor any major complication such as marked infarction of tissue or misplacement of embolic materials. This coaxial catheter system was highly reliable for achieving superselective catheterization in small-caliber arteries, minimizing the volume of infarcted tissue and allowing maximal preservation of splanchnic organic function. We conclude that this system represents a major advance in interventional radiology. (orig.)

  18. Prevalence and correlates of central venous catheter use among haemodialysis patients in the Irish health system - a national study.

    Science.gov (United States)

    Hussein, Wael F; Mohammed, Husham; Browne, Leonard; Plant, Liam; Stack, Austin G

    2018-04-02

    Central venous catheters (CVC) are associated with substantial morbidity and mortality among patients undergoing haemodialysis (HD), yet they are frequently used as the primary vascular access for many patients on HD. The goal of this study was to determine the prevalence and variation in CVC use across centres in the Irish health system. Data from the National Kidney Disease Clinical Patient Management System (KDCPMS) was used to determine CVC use and patterns across centres. Data on demographic characteristics, primary cause of end-stage kidney disease (ESKD), comorbid conditions, laboratory values and centre affiliation were extracted for adult HD patients (n = 1, 196) who were on dialysis for at least three months up to end of December 2016. Correlates of CVC use were explored using multivariable logistic regression. Overall prevalence of CVC use was 54% and varied significantly across clinical sites from 43% to 73%, P catheter use was greater for women than men, OR 1.77 (1.34-2.34) and for 2 out of 10 regional dialysis centres, OR 1.98 (1.02-3.84) and OR 2.86 (1.67-4.90) respectively compared to referent group). Catheters are the predominant type of vascular access in patients undergoing HD in the Irish health system. Substantial centre variation exists which is not explained by patient-level characteristics.

  19. The Wiley Spinal Catheter-Over-Needle System for Continuous Spinal Anesthesia: A Case Series of 5 Cesarean Deliveries Complicated by Paresthesias and Headaches.

    Science.gov (United States)

    McKenzie, Christine P; Carvalho, Brendan; Riley, Edward T

    2016-01-01

    Intrathecal catheter devices using a catheter-over-needle design and softer flexible material have been introduced to clinical practice with the aim of reducing some of the complications such as postdural puncture headaches and paresthesias seen with previous versions of intrathecal catheters. We present a case series of 5 cesarean deliveries using the Wiley Spinal intrathecal system (Epimed, Johnstown, New York), which was recently approved by the US Food and Drug Administration. The intrathecal catheter system consists of a flexible 23-gauge intrathecal cannula over a 27-gauge pencil-point spinal needle. The placement of the intrathecal catheter was successful in all 5 cases; however, paresthesias in 3 cases and postdural puncture headaches in 2 cases complicated the placement and use of the device. Although the unique catheter-over-needle design facilitates the use of smaller-gauge spinal needles for dural puncture and larger-gauge catheters for medication administration, this case series using the Wiley Spinal suggests that paresthesias and postdural puncture headaches may still limit its widespread utilization. Future studies are needed to determine the true incidence of complications and to determine the role of continuous spinal anesthesia in the obstetric population.

  20. Dynamic response of a neonatal catheter-manometer system in situ.

    Science.gov (United States)

    van Langen, H; Brienesse, P; Kopinga, K; Wijn, P

    1993-11-01

    The purpose of this study was to develop, validate, and apply a flush-pulse method to determine the dynamic response of a neonatal catheter-manometer system (CMS) in situ. In the flush-pulse method, the opened fast-flush valve of the CMS is closed; as a result, the fluid column in the CMS is impacted. This procedure can be done without affecting the net flow of infusion fluid. We validated the method in laboratory conditions by comparing 14 paired results obtained with this method to the results obtained using a generally accepted step-response method. The measurable values are the resonance frequency (fr) and the damping coefficient (delta). The analysis of the flush-pulse method in situ is complicated by the patient's blood pressure wave. A remedy for this problem that is based on the first derivative of the pressure signal has been developed. The flush-pulse method is applied 14 times in situ. In laboratory settings, the fr ranged from 12.5 to 64.0 Hz and delta ranged from 0.14 to 0.32. The correlation coefficient was 0.99 for fr and 0.91 for delta. We found four overdamped systems in situ (delta > 1). In other systems fr values between 8.5 and 41.0 Hz and delta values between 0.16 and 0.72 were observed. The dynamic response in situ appeared to deteriorate with time due to routine intensive care procedures. The flush-pulse method proved to be a valid test for determining the dynamic response. The results obtained in situ emphasize the need for a regular evaluation of the dynamic response of the neonatal CMS in order to assess the shape of the pressure wave.

  1. Robotic positioning of standard electrophysiology catheters: a novel approach to catheter robotics.

    Science.gov (United States)

    Knight, Bradley; Ayers, Gregory M; Cohen, Todd J

    2008-05-01

    Robotic systems have been developed to manipulate and position electrophysiology (EP) catheters remotely. One limitation of existing systems is their requirement for specialized catheters or sheaths. We evaluated a system (Catheter Robotics Remote Catheter Manipulation System [RCMS], Catheter Robotics, Inc., Budd Lake, New Jersey) that manipulates conventional EP catheters placed through standard introducer sheaths. The remote controller functions much like the EP catheter handle, and the system permits repeated catheter disengagement for manual manipulation without requiring removal of the catheter from the body. This study tested the hypothesis that the RCMS would be able to safely and effectively position catheters at various intracardiac sites and obtain thresholds and electrograms similar to those obtained with manual catheter manipulation. Two identical 7 Fr catheters (Blazer II; Boston Scientific Corp., Natick, Massachusetts) were inserted into the right femoral veins of 6 mongrel dogs through separate, standard 7 Fr sheaths. The first catheter was manually placed at a right ventricular endocardial site. The second catheter handle was placed in the mating holder of the RCMS and moved to approximately the same site as the first catheter using the Catheter Robotics RCMS. The pacing threshold was determined for each catheter. This sequence was performed at 2 right atrial and 2 right ventricular sites. The distance between the manually and robotically placed catheters tips was measured, and pacing thresholds and His-bundle recordings were compared. The heart was inspected at necropsy for signs of cardiac perforation or injury. Compared to manual positioning, remote catheter placement produced the same pacing threshold at 7/24 sites, a lower threshold at 11/24 sites, and a higher threshold at only 6/24 sites (p > 0.05). The average distance between catheter tips was 0.46 +/- 0.32 cm (median 0.32, range 0.13-1.16 cm). There was no difference between right atrial

  2. Feasibility of Endovascular Radiation Therapy Using Holmium-166 Filled Balloon Catheter in a Swine Hemodialysis Fistula Model: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Won, Jong Yun; Lee, Kwang Hun; Lee, Do Yun [Dept. of Radiology, Research Institute of Radiological Science, Yensei University College of Medicine, Seoul (Korea, Republic of); Kim, Myoung Soo [Dept. of Radiology, Yensei University College of Medicine, Seoul (Korea, Republic of); Kang, Byung Chul [Dept. of Radiology, Internal Medicine, EwhaWoman' s University School of Medicine, Seoul (Korea, Republic of); Kim, Seung Jung [Dept. of Internal Medicine, EwhaWoman' s University School of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    To describe how to make a swine hemodialysis fistula model and report our initial experience to test the feasibility of endovascular radiation therapy with Holmium-166 filled balloon catheters. The surgical formation of arterio-venous fistula (AVF) was performed by end-to-side anastomosis of the bilateral jugular vein and carotid artery of 6 pigs. After 4 weeks, angiograms were taken and endovascular radiation was delivered to the venous side of AVF with Holmium-166 filled balloon catheters. Pigs were sacrificed 4 weeks after the radiation and AVFs were harvested for histological examination. All animals survived without any morbidity during the experimental periods. The formation of fistula on the sides of necks was successful in 11 of the 12 pigs (92%). One AVF failed from the small jugular vein. On angiograms, 4 of the 11 AVFs showed total occlusion or significant stenosis and therefore, endovascular radiation could not be performed. Of 7 eligible AVFs, five underwent successful endovascular radiation and two AVFs did not undergo radiation for the control. Upon histologic analysis, one non-radiated AVF showed total occlusion and others showed intimal thickening from the neointimal hyperplasia. Formation of the swine carotid artery-jugular vein hemodialysis fistula model was successful. Endovascular radiation using a Holmium-166 filled balloon catheter was safe and feasible.

  3. [Recording of ventricular pressure by conventional catheter manometer systems. I. Minimal requirements of blood pressure recording systems and estimation of frequency response characteristics].

    Science.gov (United States)

    Hellige, G

    1976-01-01

    Parallel recordings of pressure pulses by conventional catheter manometer systems and catheter tip manometer demonstrate severe errors in the peak velocity of pressure rise estimated by conventional systems. This fact is due to inadequate dynamic response characteristics of conventional systems in relation to the frequency content of pressure curves. During cardiac rest the error in dp/dt max is less than 10% if the frequency response of the recording system is uniform up to 10 Hz, the corresponding value under maximal cardiac stimulation is about 40 Hz. This is equal to the first 10 harmonics of heart rate. The examination of left and right ventricular pressure curves leads to similar results. The experimental determination of dynamic response characteristics of cathermanometer systems requires a test system producing suitable sinus or step functions, parallel high fidelity recording of pressure functions to be recommended. A simple test station is described. Examinations of temperature influence on catheter material and resulting changes in dynamic response characteristics were carried out. The incubation of catheters at the temperature of 37 degrees C is indispensable. A new diagram for simplifying the interpretation of results is described. Other publications are discussed in viewpoint of employed techniques and representation of results.

  4. Catheter Angiography

    Medline Plus

    Full Text Available ... or other procedures such as chemoembolization or selective internal radiation therapy. identify dissection or splitting in the aorta in the chest or abdomen or its major branches. show the extent and severity of ... the artery, causing internal bleeding. It also is possible that the catheter ...

  5. Catheter Angiography

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Catheter Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. ...

  6. Catheter Angiography

    Medline Plus

    Full Text Available ... the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs. risks? What are the limitations of Catheter Angiography? What ...

  7. Catheter Angiography

    Medline Plus

    Full Text Available ... spaghetti. top of page How does the procedure work? Catheter angiography works much the same as a regular x-ray ... any possibility that they are pregnant. See the Safety page for more information about pregnancy and x- ...

  8. Atrial fibrillation and sudden cardiac death: catheter-based sensor and mapping system of the heart

    Science.gov (United States)

    Ramasamy, Mouli; Kumar, Prashanth S.; Varadan, Vijay K.

    2017-04-01

    Ventricular arrhythmias in the heart and the rapid heartbeat of ventricular tachycardia can lead to sudden cardiac death. This is a major health issue worldwide. What is needed is to develop a catheter based sensor and mapping approach which will provide the mechanisms of ventricular arrhythmia, and effectively prevent and treat the same, potentially save life.

  9. Postoperative Catheter-Directed Thrombolysis Versus Systemic Anticoagulation for Acute Superior Mesenteric Venous Thrombosis.

    Science.gov (United States)

    Yang, Shuofei; Zhang, Lan; Liu, Kai; Fan, Xinxin; Ding, Weiwei; He, Changsheng; Wu, Xingjiang; Li, Jieshou

    2016-08-01

    Little data evaluate catheter-directed thrombolysis (CDT) therapy as a sequential treatment of emergent surgery for patients with acute superior mesenteric venous thrombosis (ASMVT). We compared the outcomes of ASMVT patients receiving CDT via superior mesenteric artery (SMA) with those who had systemic anticoagulation after emergent laparotomy. A single-center retrospective study of ASMVT patients receiving emergent laparotomy from May 2012 to April 2014 was performed. Patients in group I had postoperative systemic anticoagulation and patients in group II underwent postoperative CDT. The demography, etiology, imaging features, clinical outcomes, and complications were compared. Moreover, univariate analysis was performed to identify confounding variables of 30-day mortality. Thirty-two patients (20 males, mean age of 44.9 ± 10.6 years) were included, 17 in group I and 15 in group II. No significant differences of demographic data, etiology, baseline value, and perioperative comorbidity were found. The rate of complete thrombus removal was significantly higher in group II than group I (29.4% vs. 80.0%, P = 0.001). The second-look laparotomy and repeat bowel resection (58.8% vs. 13.3%, P = 0.002) were required in fewer patients in group II (20.0% vs. 70.6%, P = 0.001). The incidence of short-bowel syndrome (SBS; 41.2% vs. 6.7%, P = 0.001) and 30-day mortality (41.2% vs. 6.7%, P = 0.001) were lower in group II. The 1-year survival was also better in group II (52.9% vs. 93.3%, P = 0.014). The incidence of massive abdominal hemorrhage requiring blood transfusion and surgical intervention was 11.8% in group I and 20.0% in group II (P = 0.645). The age, serum D-dimer level, SBS, and postoperative CDT were significant risk factors of 30-day mortality in this study. For ASMVT patients receiving emergent surgery and intraoperative thrombectomy, the algorithm with postoperative CDT via SMA is associated with more favorable clinical outcome compared with

  10. A computational fluid dynamics simulation framework for ventricular catheter design optimization.

    Science.gov (United States)

    Weisenberg, Sofy H; TerMaath, Stephanie C; Barbier, Charlotte N; Hill, Judith C; Killeffer, James A

    2017-11-10

    OBJECTIVE Cerebrospinal fluid (CSF) shunts are the primary treatment for patients suffering from hydrocephalus. While proven effective in symptom relief, these shunt systems are plagued by high failure rates and often require repeated revision surgeries to replace malfunctioning components. One of the leading causes of CSF shunt failure is obstruction of the ventricular catheter by aggregations of cells, proteins, blood clots, or fronds of choroid plexus that occlude the catheter's small inlet holes or even the full internal catheter lumen. Such obstructions can disrupt CSF diversion out of the ventricular system or impede it entirely. Previous studies have suggested that altering the catheter's fluid dynamics may help to reduce the likelihood of complete ventricular catheter failure caused by obstruction. However, systematic correlation between a ventricular catheter's design parameters and its performance, specifically its likelihood to become occluded, still remains unknown. Therefore, an automated, open-source computational fluid dynamics (CFD) simulation framework was developed for use in the medical community to determine optimized ventricular catheter designs and to rapidly explore parameter influence for a given flow objective. METHODS The computational framework was developed by coupling a 3D CFD solver and an iterative optimization algorithm and was implemented in a high-performance computing environment. The capabilities of the framework were demonstrated by computing an optimized ventricular catheter design that provides uniform flow rates through the catheter's inlet holes, a common design objective in the literature. The baseline computational model was validated using 3D nuclear imaging to provide flow velocities at the inlet holes and through the catheter. RESULTS The optimized catheter design achieved through use of the automated simulation framework improved significantly on previous attempts to reach a uniform inlet flow rate distribution using

  11. Effect of Left Atrial Ablation Process and Strategy on Microemboli Formation During Irrigated Radiofrequency Catheter Ablation in an In Vivo Model.

    Science.gov (United States)

    Takami, Mitsuru; Lehmann, H Immo; Parker, Kay D; Welker, Kirk M; Johnson, Susan B; Packer, Douglas L

    2016-01-01

    Formation of microemboli during catheter ablation has been suggested as a cause for asymptomatic cerebral emboli. However, it is unknown which part of the process and ablation setting/strategy is most strongly related to this occurrence. A total of 27 pigs were used. Catheter/sheath manipulations in left atrium were performed in 25 of 27 pigs outfitted with microemboli monitoring systems. Ablations using open-irrigated radiofrequency catheters were performed in 18 of 25 pigs. Two of 27 pigs did not undergo left atrial procedures and were injected with microembolic materials in the carotid artery to serve as positive controls. In total, 334 sheath/catheter manipulations (transseptal puncture, sheath flushing, catheter insertion, pulmonary vein venography, and sheath exchange) and 333 radiofrequency applications (power setting, 30/50 W; point-by-point/drag ablations) were analyzed. High microbubble volume in the extracorporeal circulation loop and a high number of microembolic signals in carotid artery were observed during sheath/catheter manipulations especially in saline/contrast injections at fast speed and ablations with steam pop. Fast sheath flushing produced significantly higher microbubble volume than slow sheath flushing (median, 12 200 versus 121 nL; Pdrag ablations, and steam pop. Brain magnetic resonance imaging showed positive-embolic lesions in control pigs. Formation of microbubbles was the greatest during fast saline/contrast injections and steam pops, whereas high-power radiofrequency applications, drag ablations, and steam pops produced most of the microparticles. © 2016 American Heart Association, Inc.

  12. The Leaflex™ Catheter System - a viable treatment option alongside valve replacement? Preclinical feasibility of a novel device designed for fracturing aortic valve.

    Science.gov (United States)

    Jonas, Michael; Rozenman, Yoseph; Moshkovitz, Yaron; Hamdan, Ashraf; Kislev, Yael; Tirosh, Nitzan; Sax, Sharon; Trumer, Dror; Golan, Erez; Raanani, Ehud

    2015-09-01

    To demonstrate the feasibility of the Leaflex™ Catheter System, a novel percutaneous device for fracturing valve calcification using mechanical impact in order to regain leaflet mobility. Radiographic analysis of calcium patterns in 90 ex vivo human aortic valve leaflets demonstrated that 82% of leaflets had a typical "bridge" or "half-bridge" pattern, which formed the basis for the catheter design. The therapeutic effect was quantified in 13 leaflets showing a reduction of 49±16% in leaflet resistance to folding after treatment. A pulsatile flow simulator was then used with 11 ex vivo valves demonstrating an increase in aortic valve area of 35±12%. Using gross pathology and histology on fresh calcified leaflets, we then verified that mechanical impacts do not entail excessive risk of embolisation. In vivo safety and usability were then confirmed in the ovine model. We demonstrated preclinically that it is feasible to improve valve function using the Leaflex™ technology. Once demonstrated clinically, such an approach may have an important role as preparation for or bridging to TAVI, as destination treatment for patients where TAVI is clinically or economically questionable and, in the future, maybe even as a means to slow disease progression in asymptomatic patients.

  13. WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, E; Racine, E; Beaulieu, L [CHU de Quebec - Universite Laval, Quebec, Quebec (Canada); Binnekamp, D [Integrated Clinical Solutions and Marketing, Philips Healthcare, Best, DA (Netherlands)

    2014-06-15

    Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.

  14. Indwelling catheter care

    Science.gov (United States)

    Foley catheter ... You will need to make sure your indwelling catheter is working properly. You will also need to ... not get an infection or skin irritation. Make catheter and skin care part of your daily routine. ...

  15. An In Vivo Rabbit Model for the Evaluation of Antimicrobial Peripherally Inserted Central Catheter to Reduce Microbial Migration and Colonization as Compared to an Uncoated PICC

    Directory of Open Access Journals (Sweden)

    Nicholas D. Allan

    2012-01-01

    Full Text Available Infection is the leading complication associated with intravascular devices, and these infections develop when a catheter becomes colonized by microorganisms. To combat this issue, medical device manufacturers seek to provide healthcare facilities with antimicrobial medical devices to prevent or reduce the colonization. In order to adequately evaluate these devices, an in vivo model is required to accurately assess the performance of the antimicrobial devices in a clinical setting. The model presented herein was designed to provide a simulation of the subcutaneous tunnel environment to evaluate the ability of an antimicrobial peripherally inserted central catheter (PICC, coated with chlorhexidine based technology, to reduce microbial migration and colonization compared to an uncoated PICC. Three samples of control, uncoated PICCs and three samples of coated PICCs were surgically tunneled into the backs of female New Zealand White rabbits. The insertion sites were then challenged with Staphylococcus aureus at the time of implantation. Animals were evaluated out to thirty days and sacrificed. Complete en bloc dissection and evaluation of the catheter and surrounding tissue demonstrated that the chlorhexidine coated catheter was able to significantly reduce microbial colonization and prevent microbial migration as compared to the standard, un-treated catheter.

  16. A virtual reality-based method of decreasing transmission time of visual feedback for a tele-operative robotic catheter operating system.

    Science.gov (United States)

    Guo, Jin; Guo, Shuxiang; Tamiya, Takashi; Hirata, Hideyuki; Ishihara, Hidenori

    2016-03-01

    An Internet-based tele-operative robotic catheter operating system was designed for vascular interventional surgery, to afford unskilled surgeons the opportunity to learn basic catheter/guidewire skills, while allowing experienced physicians to perform surgeries cooperatively. Remote surgical procedures, limited by variable transmission times for visual feedback, have been associated with deterioration in operability and vascular wall damage during surgery. At the patient's location, the catheter shape/position was detected in real time and converted into three-dimensional coordinates in a world coordinate system. At the operation location, the catheter shape was reconstructed in a virtual-reality environment, based on the coordinates received. The data volume reduction significantly reduced visual feedback transmission times. Remote transmission experiments, conducted over inter-country distances, demonstrated the improved performance of the proposed prototype. The maximum error for the catheter shape reconstruction was 0.93 mm and the transmission time was reduced considerably. The results were positive and demonstrate the feasibility of remote surgery using conventional network infrastructures. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Catheter Ablation of Ectopic Atrial Tachycardia Originating from the Left Atrial Appendage using CARTOMERGE® System

    Directory of Open Access Journals (Sweden)

    Masahiko Goya, MD

    2008-01-01

    Full Text Available A 70-year-old woman was referred because of drug resistant and daily incessant palpitation attack. She had undergone two previous unsuccessful radiofrequency catheter ablations at another hospital. The physical examination, chest X-ray, and echocardiogram were all normal. The 12-lead ECG during tachycardia showed narrow QRS, short PR tachycardia and negative polarity of the P wave in leads I and aVL (Fig. 1A. The ECG monitor showed incessant tachycardia with warming-up phenomenon. Three dimensional electroanatomical map integrated with CT imaging (CARTOMERGE®, Biosense Webster Inc. clearly revealed the radial activation pattern originating from the basalo-postero-inferior aspect of the left atrial appendage. Radiofrequency energy application at this site eliminated tachycardia permanently.

  18. Intravascular (catheter) MR imaging

    International Nuclear Information System (INIS)

    Cohen, A.M.; Hurst, G.C.; Katz, D.E.; Dverk, J.L.; Wiesen, E.J.; Czerski, L.W.; Malaya, R.; Bellon, E.M.

    1989-01-01

    Intravascular MR probes allow excellent spatial resolution and have the potential to detect arterial wall microstructure. Ultrasonic intravascular probes suggest that detailed morphologic information can assist clinical decision making. Catheter MR probes of 2--7 mm outside diameter (OD) were built of copper wire, Teflon, and parts from standard commercial catheters. The probes were connected to the surface coil receiver input of our Picker VISTA 2055HP 1.5-T imaging system. The extant (linear) body coil was used for transmit. Phantoms were constructed of coaxial glass MR tubes, filled with doped water. Watanabe rabbit aorta and human autopsy iliac artery specimens were examined within 4 hours of excision or stored by freezing. In vivo iliac arteries in dogs under general anesthesia were imaged, with percutaneous placement of the probe. Results are presented

  19. A catheter-based near-infrared scanning spectroscopy system for imaging lipid-rich plaques in human coronary arteries in vivo

    Science.gov (United States)

    Gardner, Craig M.; Lisauskas, Jennifer; Hull, Edward L.; Tan, Huwei; Sum, Stephen; Meese, Thomas; Jiang, Chunsheng; Madden, Sean; Caplan, Jay; Muller, James E.

    2007-09-01

    Although heart disease remains the leading cause of death in the industrialized world, there is still no method, even under cardiac catheterization, to reliably identify those atherosclerotic lesions most likely to lead to heart attack and death. These lesions, which are often non-stenotic, are frequently comprised of a necrotic, lipid-rich core overlaid with a thin fibrous cap infiltrated with inflammatory cells. InfraReDx has developed a scanning, near-infrared, optical-fiber-based, spectroscopic cardiac catheter system capable of acquiring NIR reflectance spectra from coronary arteries through flowing blood under automated pullback and rotation in order to identify lipid-rich plaques (LRP). The scanning laser source and associated detection electronics produce a spectrum in 5 ms at a collection rate of 40 Hz, yielding thousands of spectra in a single pullback. The system console analyzes the spectral data with a chemometric model, producing a hyperspectral image (a Chemogram, see figure below) that identifies LRP encountered in the region interrogated by the system. We describe the system architecture and components, explain the experimental procedure by which the chemometric model was constructed from spectral data and histology-based reference information collected from autopsy hearts, and provide representative data from ongoing ex vivo and clinical studies.

  20. Central venous catheters and catheter locks in children with cancer

    DEFF Research Database (Denmark)

    Handrup, Mette Møller; Møller, Jens Kjølseth; Schrøder, Henrik

    2013-01-01

    To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC).......To determine if the catheter lock taurolidine can reduce the number of catheter-related bloodstream infections (CRBSI) in pediatric cancer patients with tunneled central venous catheters (CVC)....

  1. Reconstruction of Intima and Adventitia Models into a State Undeformed by a Catheter by Using CT, IVUS, and Biplane X-Ray Angiogram Images

    Directory of Open Access Journals (Sweden)

    Jinwon Son

    2017-01-01

    Full Text Available The number of studies on blood flow analysis using fluid-structure interaction (FSI analysis is increasing. Though a 3D blood vessel model that includes intima and adventitia is required for FSI analysis, there are difficulties in generating it using only one type of medical imaging. In this paper, we propose a 3D modeling method for accurate FSI analysis. An intravascular ultrasound (IVUS image is used with biplane X-ray angiogram images to calculate the position and orientation of the blood vessel. However, these images show that the blood vessel is deformed by the catheter inserted into the blood vessel for IVUS imaging. To eliminate such deformation, a CT image was added and the two models were registered. First, a 3D model of the undeformed intima was generated using a CT image. In the second stage, a model of intima and adventitia deformed by the catheter was generated by combining the IVUS image and the X-ray angiogram images. A 3D model of intima and adventitia with the deformation caused by insertion of the catheter eliminated was generated by matching these 3D blood vessel models in different states. In addition, a 3D blood vessel model including bifurcation was generated using the proposed method.

  2. CFD modeling of catheter-based Chemofilter device for filtering chemotherapy drugs from venous flow

    Science.gov (United States)

    Maani, Nazanin; Yee, Daryl; Nosonovsky, Michael; Greer, Julia; Hetts, Steven; Rayz, Vitaliy

    2017-11-01

    Purpose: Intra-arterial chemotherapy, a procedure where drugs are injected into arteries supplying a tumor, may cause systemic toxicity. The Chemofilter device, deployed in a vein downstream of the tumor, can chemically filter the excessive drugs from the circulation. In our study, CFD modeling of blood flow through the Chemofilter is used to optimize its hemodynamic performance. Methods:The Chemofilter consists of a porous membrane attached to a stent-like frame of the RX Accunet distal protection filters used for capturing blood clots. The membrane is formed by a lattice of symmetric micro-cells. This design provides a large surface area for the drug binding, and allows blood cells to pass through the lattice. A two-scale modeling approach is used, where the flow through individual micro-cells is simulated to determine the lattice permeability and then the entire device is modeled as a porous membrane. Results: The simulations detected regions of flow stagnation and recirculation caused by the membrane and its supporting frame. The effect of the membrane's leading angle on the velocity and pressure fields was determined. The device optimization will help the efficacy of drug absorption, while the risk of blood clotting reduces. NIH NCI R01CA194533.

  3. A virtual-reality simulator and force sensation combined catheter operation training system and its preliminary evaluation.

    Science.gov (United States)

    Wang, Yu; Guo, Shuxiang; Tamiya, Takashi; Hirata, Hideyuki; Ishihara, Hidenori; Yin, Xuanchun

    2017-09-01

    Endovascular surgery benefits patients because of its superior short convalescence and lack of damage to healthy tissue. However, such advantages require the operator to be equipped with dexterous skills for catheter manipulation without resulting in collateral damage. To achieve this goal, a training system is in high demand. A training system integrating a VR simulator and a haptic device has been developed within this context. The VR simulator is capable of providing visual cues which assist the novice for safe catheterization. In addition, the haptic device cooperates with VR simulator to apply sensations at the same time. The training system was tested by non-medical subjects over a five days training session. The performance was evaluated in terms of safety criteria and task completion time. The results demonstrate that operation safety is improved by 15.94% and task completion time is cut by 18.80 s maximum. Moreover, according to subjects' reflections, they are more confident in operation. The proposed training system constructs a comprehensive training environment that combines visualization and force sensation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. [Reduction of radiological exposure time during radiofrequency catheter ablation procedures using a novel intracardiac localization system based on the Ohm's law].

    Science.gov (United States)

    Catanzariti, Domenico; Maines, Massimiliano; De Girolamo, Piergiuseppe; Cozzi, Fulvio; Cemin, Claudio; Vergara, Giuseppe

    2004-08-01

    Three-dimensional nonfluoroscopic system may be helpful to guide radiofrequency catheter ablation procedures and to reduce the radiological exposure. A new intracardiac navigation and multicatheter visualization system based on Ohm's law (LocaLisa, Medtronic, Minneapolis, MN, USA) has been recently introduced. The aim of our study was to assess the efficacy of the Loca-Lisa system in comparison to fluoroscopy-based approach in reducing the radiological exposure time required for radiofrequency catheter ablation procedures. One hundred and thirty-seven consecutive patients underwent LocaLisa-based radiofrequency catheter ablation procedures in our cardiac electrophysiology laboratory during 19 months of LocaLisa utilization (from October 2001 to April 2003): 46 atrial flutter, 44 atrioventricular node reentrant tachycardia, 16 atrioventricular reentry tachycardia due to atrioventricular accessory pathway, 14 atrial fibrillation, 11 ectopic atrial tachycardia, and 6 atrioventricular node modulation. We retrospectively compared the radiological exposure times of this group of patients to those of the last 137 patients undergone fluoroscopy-based radiofrequency catheter ablation procedures for curing the same index arrhythmia by the same procedural protocol. The mean radiological exposure time was significantly shorter for the LocaLisa-based radiofrequency catheter ablation procedures (16 +/- 12 vs 34 +/- 17 min; reduction of 53%, p < 0.01) and it occurred for all the arrhythmia types. The reduction was of 64% (from 39 +/- 18 to 14 +/- 12 min, p < 0.01) for atrial flutter, 42% (from 24 +/- 10 to 14 +/- 11 min, p < 0.01) for atrioventricular nodal reentrant tachycardia, 30% (from 40 +/- 14 to 28 +/- 14 min, p = 0.02) for atrioventricular reentry tachycardia, 57% (from 49 +/- 12 to 21 +/- 13 min, p < 0.01) for atrial fibrillation (right atrial linear lesions), 50% (from 38 +/- 12 to 19 +/- 8 min, p < 0.01) for ectopic atrial tachycardia and 42% (from 12 +/- 11 to 7 +/- 5

  5. Comparison of the Effectiveness of a Virtual Simulator With a Plastic Arm Model in Teaching Intravenous Catheter Insertion Skills.

    Science.gov (United States)

    Günay İsmailoğlu, Elif; Zaybak, Ayten

    2018-02-01

    The objective of this study was to compare the effectiveness of a virtual intravenous simulator with a plastic arm model in teaching intravenous catheter insertion skills to nursing students. We used a randomized controlled quasi-experimental trial design and recruited 65 students who were assigned to the experimental (n = 33) and control (n = 32) groups using the simple random sampling method. The experimental group received intravenous catheterization skills training on the virtual intravenous simulator, and the control group received the same training on a plastic model of a human arm. Data were collected using the personal information form, intravenous catheterization knowledge assessment form, Intravenous Catheterization Skill Test, Self-Confidence and Satisfaction Scale, and Fear Symptoms Scale. In the study, the mean scores in the control group were 20.44 for psychomotor skills, 15.62 for clinical psychomotor skills, 31.78 for self-confidence, and 21.77 for satisfaction. The mean scores in the experimental group were 45.18 for psychomotor skills, 16.28 for clinical psychomotor skills, 34.18 for self-confidence, and 43.89 for satisfaction. The results indicated that psychomotor skills and satisfaction scores were higher in the experimental group, while the clinical psychomotor skills and self-confidence scores were similar in both groups. More students in the control group reported experiencing symptoms such as cold and sweaty hands, significant restlessness, and tense muscles than those in the experimental group.

  6. Renal access in PNL under sonographic guidance: Do we really need to insert an open end ureteral catheter in dilated renal systems? A prospective randomized study.

    Science.gov (United States)

    Eryildirim, Bilal; Tuncer, Murat; Camur, Emre; Ustun, Fatih; Tarhan, Fatih; Sarica, Kemal

    2017-10-03

    To evaluate the true necessity of open end ureteral catheter insertion in patients with moderate to severe pelvicalyceal system dilation treated with percutaneous nephrolithotomy (PNL) under sonographic guidance. 50 cases treated with PNL under sonographic guidance in prone position for solitary obstructing renal stones were evaluated. Patients were randomly divided into two groups; Group 1: Patients in whom a open end ureteral catheter was inserted prior to the procedure; Group 2: Patients receiving no catheter before PNL. In addition to the duration of the procedure as a whole and also all relevant stages as well, radiation exposure time, hospitalization period, mean nephrostomy tube duration, mean drop in Hb levels and all intra and postoperative complications have been evaluated. Mean size of the stones was 308.5 ± 133.2 mm2. Mean total duration of the PNL procedure in cases with open end ureteral catheter was significantly longer than the other cases (p < 0.001). Evaluation of the outcomes of the PNL procedures revealed no statistically significant difference between two groups regarding the stone-free rates (86% vs 84%). Additionally, there was no significant difference with respect to the duration of nephrostomy tube, hospitalization period and secondary procedures needed, complication rates as well as the post-operative Hb drop levels in both groups (p = 0.6830). Our results indicate that the placement of an open end ureteral catheter prior to a PNL procedure performed under sonographic access may not be indicated in selected cases presenting with solitary obstructing renal pelvic and/or calyceal stones.

  7. The Effect of Model Fidelity on Learning Outcomes of a Simulation-Based Education Program for Central Venous Catheter Insertion.

    Science.gov (United States)

    Diederich, Emily; Mahnken, Jonathan D; Rigler, Sally K; Williamson, Timothy L; Tarver, Stephen; Sharpe, Matthew R

    2015-12-01

    Simulation-based education for central venous catheter (CVC) insertion has been repeatedly documented to improve performance, but the impact of simulation model fidelity has not been described. The aim of this study was to examine the impact of the physical fidelity of the simulation model on learning outcomes for a simulation-based education program for CVC insertion. Forty consecutive residents rotating through the medical intensive care unit of an academic medical center completed a simulation-based education program for CVC insertion. The curriculum was designed in accordance with the principles of deliberate practice and mastery learning. Each resident underwent baseline skills testing and was then randomized to training on a commercially available CVC model with high physical fidelity (High-Fi group) or a simply constructed model with low physical fidelity (Low-Fi group) in a noninferiority trial. Upon completion of their medical intensive care unit rotation 4 weeks later, residents returned for repeat skills testing on the high-fidelity model using a 26-item checklist. The mean (SD) posttraining score on the 26-item checklist for the Low-Fi group was 23.8 (2.2) (91.5%) and was not inferior to the mean (SD) score for the High-Fi group of 22.5 (2.6) (86.5%) (P Simulation-based education using equipment with low physical fidelity can achieve learning outcomes comparable with those with high-fidelity equipment, as long as other aspects of fidelity are maintained and robust educational principles are applied during the design of the curriculum.

  8. Unintended Thermal Injuries from Radiofrequency Ablation: Organ Protection with an Angioplasty Balloon Catheter in an Animal Model

    Directory of Open Access Journals (Sweden)

    Martha-Grace Knuttinen

    2014-01-01

    Full Text Available Objectives: The aim of this study was to investigate a novel approach of using a balloon catheter as a protective device to separate liver from the diaphragm or nearby bowel during radiofrequency ablation (RFA of hepatic dome tumors in an animal model. Materials and Methods: All experimental procedures were approved by animal Institutional Review Board. Using a 3 cm RF needle electrode, 70 hepatic ablation zones were created using ultrasound in 7 pigs. 50 lesions were created using balloon interposition between liver and diaphragm; 20 lesions were created using the balloon device interposed posteriorly between liver and bowel. Additional 21 control lesions were performed. Animals were sacrificed immediately; diaphragm and bowel were then visually inspected and sectioned. Diaphragmatic and bowel injury was then classified according to the depth of thickness. Results: Control lesions caused full thickness injury, either to diaphragm or bowel. During ablation of lesions with balloon interposition, there was significantly less diaphragmatic injury, P < 0.001 and less bowel injury, P < 0.01. Conclusion: Using balloon interposition as a protective device has advantages over previous saline infusion or CO 2 insufflation, providing a safe way to expand percutaneous RFA of liver tumors located on the undersurface of the diaphragm. In addition, this method may be used in protection of other organs adjacent to areas being ablated.

  9. Catheter-based flow measurements in hemodialysis fistulas - Bench testing and clinical performance

    DEFF Research Database (Denmark)

    Heerwagen, Søren T; Lönn, Lars; Schroeder, Torben V

    2012-01-01

    Purpose: The purpose of this study was to perform bench and clinical testing of a catheter-based intravascular system capable of measuring blood flow in hemodialysis vascular accesses during endovascular procedures. Methods: We tested the Transonic ReoCath Flow Catheter System which uses...... the thermodilution method. A simulated vascular access model was constructed for the bench test. In total, 1960 measurements were conducted and the results were used to determine the accuracy and precision of the catheters, the effects of external factors (e.g., catheter placement, injection duration), and to test....... Blood flow measurements provide unique information on the hemodynamic status of a vascular access and have the potential to optimize results of interventions....

  10. Biofilm Formation by Pseudomonas Species Onto Graphene Oxide-TiO2 Nanocomposite-Coated Catheters: In vitro Analysis

    Science.gov (United States)

    Deb, Ananya; Vimala, R.

    The present study focuses on the development of an in vitro model system for biofilm growth by Pseudomonas aerouginosa onto small discs of foley catheter. Catheter disc used for the study was coated with graphene oxide-titanium oxide composite (GO-TiO2) and titanium oxide (TiO2) and characterized through XRD, UV-visible spectroscopy. Morphological analysis was done by scanning electron microscopy (SEM). The biofilm formed on the catheter surface was quantified by crystal violet (CV) staining method and a colorimetric assay (MTT assay) which involves the reduction of tetrazolium salt. The catheter coated with GO-TiO2 showed reduced biofilm growth in comparison to the TiO2-coated and uncoated catheter, thus indicating that it could be successfully used in coating biomedical devices to prevent biofilm formation which is a major cause of nosocomial infection.

  11. Whole bladder photodynamic therapy: critical review of present-day technology and rationale for development of intravesical laser catheter and monitoring system.

    Science.gov (United States)

    Nseyo, U O; Lundahl, S L; Merrill, D C

    1990-11-01

    Present-day whole bladder photodynamic therapy (WBPDT) is cumbersome and time consuming because cystoscopic and ultrasonic manipulations are necessary to position the light emitter within the bladder. More important, WBPDT is inherently unsafe and often ineffective since neither uniform photoirradiation nor accurate light dosimetry can be achieved with the techniques employed to photoirradiate the bladder wall. The intravesical laser catheter (IVLC) eliminates the need for cystoscopy and ultrasonography because passage of the treatment fiber into the catheter's central lumen automatically positions its light-diffusing tip within the center of the bladder. Use of the IVLC delivery system also assures accurate photoirradiation of the bladder wall since inflation of the catheter's balloon transforms the asymmetric bladder into a sphere of known diameter. The light sensor incorporated in the balloon wall provides a method to monitor light fluence and measure total light dose. When provided the parameters of bladder volume, laser energy output, and desired light dose, the computerized control system calculates treatment time and automatically adjusts the period of photoirradiation to compensate for variations in laser light production, energy losses during transmission, and for variations in light intensity resulting from the integrating sphere effect of the bladder wall. This delivery system also increases the safety of WBPDT since the monitor automatically discontinues treatment if any unsafe situation, with respect to light fluence, develops during photoirradiation.

  12. Hemodynamic support with the pulsatile catheter pump in a sheep model of acute heart failure

    NARCIS (Netherlands)

    Li, Zhicheng; Gu, Y. John; Ye, Qing; Cheng, Shaofei; Wang, Weijun; Tang, Min; Zhao, Xiaogang; Rakhorst, Gerhard; Chen, Changzhi

    2006-01-01

    This study was aimed to mimic clinical heart failure (HF) conditions and to assess the effect of pulsatilecatheter (PUCA) pump support on hemodynamics and tissue perfusion in a sheep model of acute HF. In 14 sheep, HF was induced by partial occluding the middle left circumflex coronary artery

  13. Catheter visualisation in MR tomography: first animal experimental experiences with field inhomogeneity catheters

    International Nuclear Information System (INIS)

    Adam, G.; Glowinski, A.; Neuerburg, J.; Buecker, A.; Vaals, J.J. van; Hurtak, W.; Guenther, R.W.

    1997-01-01

    Purpose: To assess the feasibility of a new developed field inhomogeneity catheter for interventional MR imaging in vivo. Materials and methods: Three different prototypes of a field inhomogeneity catheter were investigated in 6 pigs. The catheters were introduced in Seldinger technique via the femoral vessels over a guide wire on an interventional MR system (Philips Gyroscan NT combined with a C-arm fluoroscopy unit [Philips BV 212[). Catheters were placed in veins and arteries. The catheter position was controlled by a fast gradient echo sequence (Turbo Field Echo [TEF[). Results: Catheters were introduced over a guide wire without complications in all cases. Using the field inhomogeneity concept, catheters were easily visualised in the inferior vena cava and the aorta by the fast gradient echo technique on MR in all cases. Although aortic branches were successfully cannulated, the catheters were not displayed by the TFE technique due to the complex and tortuous anatomy. All animals survived the experiments without complications. Conclusion: MR guided visualisation of a field inhomogeneity catheter is a simple concept which can be realised on each MR scanner and may allow intravascular MR guided interventions in future. (orig.) [de

  14. [Outpatient monitoring of oesophageal pH with a catheter-free pH-meter (Bravo System). A Study of tolerance, safety and efficacy].

    Science.gov (United States)

    Martínez de Haro, Luisa F; Munitiz, Vicente; Ortiz, Angeles; Ruiz de Angulo, David; Navarro, M Dolores; Parrilla, Pascual

    2008-10-01

    A new catheter-free outpatient oesophageal pH-meter system (Bravo) has recently been developed. The objective of this study is to test the tolerance, safety and efficacy of the system in the measurement of gastric-oesophageal reflux by comparing it with a conventional pH system. The study was performed on a control group consisting of 10 healthy volunteers (group 1) and in a group of 40 patients with symptoms of gastric-oesophageal reflux disease (groups 2 and 3). An upper digestive system endoscopy, oesophageal manometry and oesophageal pH measurements with a conventional system and/or with the Bravo catheter-free system, was performed on all patients. All patients who had both tests done (groups 1 and 2) filled in a questionnaire on any physical problems and changes in their daily activity. The test tolerance was higher with the Bravo system in the 9 parameters studied. In the group of healthy volunteers (group 1), the median (range) of the total percentage of pH pH and 1.7% (0-3.4) with the Bravo. When comparing the patients with symptoms of gastric-oesophageal reflux disease (group 2) with those who had only one type of pH measurement made, the acid reflux was significantly higher in patients with Barrett's oesophagus than in the rest of the groups, with conventional pH as well as with the Bravo. If we analyse the patient group with disease due to gastric-oesophageal reflux with those on whom both techniques were used (group 3), 7 of the 10 patients had a pathological reflux that only showed up on measuring pH with the Bravo system. Catheter-free pH measurements (Bravo) is better tolerated and with better satisfaction for the healthy volunteers and patients than with conventional PH, even, on occasions being more efficient for studying acid reflux due to the lower incidence of negative results.

  15. Backup support of the mother-child technique: technical considerations for the size of the mother guiding catheter.

    Science.gov (United States)

    Takeshita, Satoshi; Takagi, Ayumu; Saito, Shigeru

    2012-08-01

    We previously proposed a technique called the "mother-child technique" to facilitate stent delivery for complex coronary lesions. This technique is applicable when the backup support of the guiding catheter is insufficient. In this study, we used an in vitro coronary artery tree model to determine the impact of the size of the mother guiding catheter on the backup support of the mother-child guiding system. The backup support was measured for the 4-in-5, 4-in-6, 4-in-7, and 4-in-8 systems as well as for the 5-in-6, 5-in-7, and 5-in-8 systems. Advancement of the child catheter into the coronary artery tree model improved the backup support of the mother-child system. When a 4-Fr child catheter was advanced by 9 cm, the relative increase in the backup support was 174% in the 4-in-5 system; it was 203% in the 4-in-6, and 135% in the 4-in-7 system (P guiding catheter. Thus, the mother-child technique may be most useful for PCIs in which a small guiding catheter is used, such as transradial coronary interventions. Copyright © 2012 Wiley Periodicals, Inc.

  16. In vitro analysis of balloon cuffing phenomenon: inherent biophysical properties of catheter material or mechanics of catheter balloon deflation?

    Science.gov (United States)

    Chung, Eric; So, Karina

    2012-06-01

    To investigates the different methods of balloon deflation, types of urinary catheters and exposure to urine media in catheter balloon cuffing. Bardex®, Bard-Lubri-Sil®, Argyle®, Releen® and Biocath® were tested in sterile and E.Coli inoculated urine at 0, 14 and 28 days. Catheter deflation was performed with active deflation; passive deflation; passive auto-deflation; and excision of the balloon inflow channel. Balloon cuffing was assessed objectively by running the deflated balloon over a plate of agar and subjectively by 3 independent observers. Bardex®, Argyle® and Biocath® showed greater degree of catheter balloon cuffing (p deflation was the worst method (p 0.05). Linear regression model analysis confirmed time as the most significant factor. The duration of catheters exposure, different deflation methods and types of catheters tested contributed significantly to catheter balloon cuffing (p < 0.01).

  17. Comparative Efficacies of Tedizolid Phosphate, Linezolid, and Vancomycin in a Murine Model of Subcutaneous Catheter-Related Biofilm Infection Due to Methicillin-Susceptible and -Resistant Staphylococcus aureus.

    Science.gov (United States)

    Bayer, Arnold S; Abdelhady, Wessam; Li, Liang; Gonzales, Rachelle; Xiong, Yan Q

    2016-08-01

    Tedizolid, a novel oxazolidinone, exhibits bacteriostatic activity through inhibition of protein synthesis. The efficacies of tedizolid, linezolid, and vancomycin were compared in a murine catheter-related biofilm infection caused by methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) strains engineered for bioluminescence. We observed significantly improved efficacy in terms of decreased S. aureus densities and bioluminescent signals in the tedizolid-treated group versus the linezolid- and vancomycin-treated groups in the model of infection caused by the MSSA and MRSA strains. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. Successful radiofrequency catheter ablation assisted by the CartoSound® system for outflow tract origin nonsustained ventricular tachycardia in a patient with a severely deformed thorax

    Directory of Open Access Journals (Sweden)

    Naoaki Onishi

    2014-02-01

    Full Text Available We report the case of a 72-year-old man with a nonsustained ventricular tachycardia and a history of palpitations. He had a severely deformed thorax since childhood due to spinal caries. An integrated computed tomography image of the outflow tract region from the CartoSound® system revealed the detailed anatomical information around the origin of the tachycardia and that the left anterior descending coronary artery was very close (<10 mm to the target site. We carefully ablated that site with a 3.5-mm cooled-tip catheter while confirming it in the sound view, and succeeded without any complications.

  19. Exploring relationships of catheter-associated urinary tract infection and blockage in people with long-term indwelling urinary catheters.

    Science.gov (United States)

    Wilde, Mary H; McMahon, James M; Crean, Hugh F; Brasch, Judith

    2017-09-01

    To describe and explore relationships among catheter problems in long-term indwelling urinary catheter users, including excess healthcare use for treating catheter problems. Long-term urinary catheter users experience repeated problems with catheter-related urinary tract infection and blockage of the device, yet little has been reported of the patterns and relationships among relevant catheter variables. Secondary data analysis was conducted from a sample in a randomised clinical trial, using data from the entire sample of 202 persons over 12 months' participation. Descriptive statistics were used to characterise the sample over time. Zero-inflated negative binomial models were employed for logistic regressions to evaluate predictor variables of the presence/absence and frequencies of catheter-related urinary tract infection and blockage. Catheter-related urinary tract infection was marginally associated with catheter blockage. Problems reported at least once per person in the 12 months were as follows: catheter-related urinary tract infection 57%, blockage 34%, accidental dislodgment 28%, sediment 87%, leakage (bypassing) 67%, bladder spasms 59%, kinks/twists 42% and catheter pain 49%. Regression analysis demonstrated that bladder spasms were significantly related to catheter-related urinary tract infection and sediment amount, and catheter leakages were marginally significantly and positively related to catheter-related urinary tract infection. Frequencies of higher levels of sediment and catheter leakage were significantly associated with higher levels of blockage, and being female was associated with fewer blockages. Persons who need help with eating (more disabled) were also more likely to have blockages. Catheter-related urinary tract infection and blockage appear to be related and both are associated with additional healthcare expenditures. More research is needed to better understand how to prevent adverse catheter outcomes and patterns of problems in

  20. [Cerebrovascular fiberoptic catheter oximetry in an intracranial pressure model in swine. New aspects of a clinical routine].

    Science.gov (United States)

    Menzel, M; Rieger, A; Roth, S; Sanchin, L; Soukup, J; Hennig, C; Furka, H; Burkert, W; Radke, J

    1997-02-01

    The reliability of continuous fibreoptic oximetry in cerebral venous blood and its correlation with intracranial and cerebral perfusion pressures (pressure-volume curve) were examined in an experimental porcine study. The pressure in the infratentorial compartment of 13 domestic pigs (18-24 kg) was gradually increased by inflating a Fogarty balloon catheter placed on the surface of the right cerebellar hemisphere and below the tentorium. Single volumes of 0.4 ml saline were injected into the inflatable balloon at 1-min intervals up to a total volume of 7 ml. Intracranial pressure (ICP), arterial blood pressure, cerebral perfusion pressure (CPP), and cerebral venous saturation measured continuously by fibreoptic oximetry and intermittent blood-gas analyses (SjO2 superior sagittal sinus) were monitored during balloon inflation. All data were down-loaded onto a PC and evaluated off-line by a commercial statistical software package. Over the whole pressure-volume curve, two phases of SjO2 behaviour were registered by continuous fibreoptic oximetry (Oximetrix 3, Abbott) (Fig. 1). CPP ranges of less than 50% reduction from the initial value showed a linear correlation (rmittl. = 0.712, P < 0.01) between both parameters (CPP-SjO2). In CPP ranges below a crucial point of about 50 mmHg no such correlation was found (rmittl = 0.176, P < 0.5). In contrast, in 3 pigs a very good correlation was found between CPP and SjO2 over the whole pressure-volume curve as measured by blood-gas analyses of samples from the cerebrovenous catheter (rmittl. = 0.84, P < 0.05). We conclude that in physiological CPP ranges down to 50 mmHg, SjO2 measurement is a reliable method of detecting oxygen desaturation in cerebrovenous blood. Below that CPP value, the fibreoptic catheter showed repeated false-high oxygen saturation values. The accuracy of SjO2 measurement seems to depend on sufficient cerebral blood flow (CBF): with decreasing CBF the amount of cerebral venous outflow is diminished. We

  1. Post-procedural Care in Interventional Radiology: What Every Interventional Radiologist Should Know-Part II: Catheter Care and Management of Common Systemic Post-procedural Complications.

    Science.gov (United States)

    Taslakian, Bedros; Sridhar, Divya

    2017-09-01

    Interventional radiology (IR) has evolved into a full-fledged clinical specialty with attendant comprehensive patient care responsibilities. Providing excellent and thorough clinical care is as essential to the practice of IR as achieving technical success in procedures. Basic clinical skills that every interventional radiologist should learn include routine management of percutaneously inserted drainage and vascular catheters and rapid effective management of common systemic post-procedural complications. A structured approach to post-procedural care, including routine follow-up and early identification and management of complications, facilitates efficient and thorough management with an emphasis on quality and patient safety. The aim of this second part, in conjunction with part 1, is to complete the comprehensive review of post-procedural care in patients undergoing interventional radiology procedures. We discuss common problems encountered after insertion of drainage and vascular catheters and describe effective methods of troubleshooting these problems. Commonly encountered systemic complications in IR are described, and ways for immediate identification and management of these complications are provided.

  2. Natural frequency/damping coefficient relationship of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure.

    Science.gov (United States)

    Kinefuchi, Y; Suzuki, T; Takiguchi, M; Yamasaki, Y; Yamamoto, M; Suwa, K

    1993-10-01

    Using a digital simulation method, we analyzed the relationship between natural frequency (fn) and damping coefficient (Zeta) of the catheter-manometer system required for high-fidelity measurement of the pulmonary arterial pressure. The pulmonary artery pressure waveform was obtained with a catheter-tip transducer and it was fed into a dynamic simulator programmed on a computer. The original waveform and the output of the simulator were compared and judged visually for the fidelity. From this analysis, the combination of fn and Zeta was obtained and was plotted on a fn-Zeta diagram. It showed as an area, which was convex on the left side and open on the right side. The left-convex endpoint was located at a damping coefficient of about 0.7. At a lower heart rate, this area was extended to the lower frequency side, while, at a higher heart rate, this area was limited to the higher frequency side. The fn-Zeta diagram was also constructed theoretically by calculating the relations between natural frequencies and damping coefficients of a second order system with the amplitude and phase error tolerance set at +/-5% respectively.

  3. Electrical and thermal effects of esophageal temperature probes on radiofrequency catheter ablation of atrial fibrillation: results from a computational modeling study.

    Science.gov (United States)

    Pérez, Juan J; D'Avila, Andre; Aryana, Arash; Berjano, Enrique

    2015-05-01

    Luminal esophageal temperature (LET) monitoring is commonly employed during catheter ablation of atrial fibrillation (AF) to detect high esophageal temperatures during radiofrequency (RF) delivery along the posterior wall of the left atrium. However, it has been recently suggested that in some cases the esophageal probe itself may serve as an RF "antenna" and promote esophageal thermal injury. The aim of this study was to assess the electrical and thermal interferences induced by different types of commercially available esophageal temperature probes (ETPs) on RF ablation. In this study, we developed a computational model to assess the electrical and thermal effects of 3 different types of ETPs: a standard single-sensor and 2 multisensor probes (1 with and 1 without metallic surfaces). LET monitoring invariably underestimated the maximum temperature reached in the esophageal wall. RF energy cessation guided by LET monitoring using an ETP yielded lower esophageal wall temperatures. Also, the phenomenon of thermal latency was observed, particularly in the setting of LET monitoring. Most importantly, while only the ETP with a metallic surface produced minimal electrical alterations, the magnitude of this interference did not appear to be clinically significant. Temperature rises in both the esophageal wall and the ETP seem to be primarily produced by thermal conduction, and not caused by electrical and/or thermal interactions between the ablation catheter and the ETP, itself. As such, the proposed notion of the "antenna effect" producing satellite esophageal lesions during AF ablation was not evident in this study. © 2015 Wiley Periodicals, Inc.

  4. Interscalene brachial plexus block for open-shoulder surgery: a randomized, double-blind, placebo-controlled trial between single-shot anesthesia and patient-controlled catheter system.

    Science.gov (United States)

    Goebel, Sascha; Stehle, Jens; Schwemmer, Ulrich; Reppenhagen, Stephan; Rath, Beatrice; Gohlke, Frank

    2010-04-01

    Interscalene brachial plexus block (ISB) is widely used as an adjuvant regional pain therapy in patients undergoing major shoulder surgery and has proved its effectiveness on postoperative pain reduction and opioid-sparing effect. This single-center, prospective, double-blind, randomized and placebo-controlled study was to compare the effectiveness of a single-shot and a patient-controlled catheter insertion ISB system after major open-shoulder surgeries. Seventy patients were entered to receive an ISB and a patient-controlled interscalene catheter. The catheter was inserted under ultrasound guidance. Patients were then assigned to receive one of two different postoperative infusions, either 0.2% ropivacaine (catheter group) or normal saline solution (single-shot group) via a disposable patient-controlled infusion pump. The study variables were amount of rescue medication, pain at rest and during physiotherapy, patient satisfaction and incidence of unwanted side effects. The ropivacaine group revealed significantly less consumption of rescue medication within the first 24 h after surgery. Incidence of side effects did not differ between the two groups. Based on our results, we recommend the use of interscalene plexus block in combination with a patient-controlled catheter system under ultrasound guidance only for the first 24 h after major open-shoulder surgery.

  5. Black-box modeling to estimate tissue temperature during radiofrequency catheter cardiac ablation: feasibility study on an agar phantom model

    International Nuclear Information System (INIS)

    Blasco-Gimenez, Ramón; Lequerica, Juan L; Herrero, Maria; Hornero, Fernando; Berjano, Enrique J

    2010-01-01

    The aim of this work was to study linear deterministic models to predict tissue temperature during radiofrequency cardiac ablation (RFCA) by measuring magnitudes such as electrode temperature, power and impedance between active and dispersive electrodes. The concept involves autoregressive models with exogenous input (ARX), which is a particular case of the autoregressive moving average model with exogenous input (ARMAX). The values of the mode parameters were determined from a least-squares fit of experimental data. The data were obtained from radiofrequency ablations conducted on agar models with different contact pressure conditions between electrode and agar (0 and 20 g) and different flow rates around the electrode (1, 1.5 and 2 L min −1 ). Half of all the ablations were chosen randomly to be used for identification (i.e. determination of model parameters) and the other half were used for model validation. The results suggest that (1) a linear model can be developed to predict tissue temperature at a depth of 4.5 mm during RF cardiac ablation by using the variables applied power, impedance and electrode temperature; (2) the best model provides a reasonably accurate estimate of tissue temperature with a 60% probability of achieving average errors better than 5 °C; (3) substantial errors (larger than 15 °C) were found only in 6.6% of cases and were associated with abnormal experiments (e.g. those involving the displacement of the ablation electrode) and (4) the impact of measuring impedance on the overall estimate is negligible (around 1 °C)

  6. A Dynamical Training and Design Simulator for Active Catheters

    Directory of Open Access Journals (Sweden)

    Georges Dumont

    2008-11-01

    Full Text Available This work addresses the design of an active multi-link micro-catheter actuated by Shape Memory Alloy (SMA micro actuators. This may be a response to one medical major demand on such devices, which will be useful for surgical explorations and interventions. In this paper, we focus on a training and design simulator dedicated to such catheters. This simulator is based on an original simulation platform (OpenMASK. The catheter is a robotic system, which is evaluated by a dynamical simulation addressing a navigation task in its environment. The design of the prototype and its mechanical model are presented. We develop an interaction model for contact. This model uses a real medical database for which distance cartography is proposed. Then we focus on an autonomous control model based on a multi-agent approach and including the behaviour description of the SMA actuators. Results of mechanical simulations including interaction with the ducts are presented. Furthermore, the interest of such a simulator is presented by applying virtual prototyping techniques for the design optimization. This optimization process is achieved by using genetic algorithms at different stages with respect to the specified task.

  7. A Dynamical Training and Design Simulator for Active Catheters

    Directory of Open Access Journals (Sweden)

    Georges Dumont

    2004-12-01

    Full Text Available This work addresses the design of an active multi-link micro-catheter actuated by Shape Memory Alloy (SMA micro actuators. This may be a response to one medical major demand on such devices, which will be useful for surgical explorations and interventions. In this paper, we focus on a training and design simulator dedicated to such catheters. This simulator is based on an original simulation platform (OpenMASK. The catheter is a robotic system, which is evaluated by a dynamical simulation addressing a navigation task in its environment. The design of the prototype and its mechanical model are presented. We develop an interaction model for contact. This model uses a real medical database for which distance cartography is proposed. Then we focus on an autonomous control model based on a multi-agent approach and including the behaviour description of the SMA actuators. Results of mechanical simulations including interaction with the ducts are presented. Furthermore, the interest of such a simulator is presented by applying virtual prototyping techniques for the design optimization. This optimization process is achieved by using genetic algorithms at different stages with respect to the specified task.

  8. Dedicated radial ventriculography pigtail catheter

    Energy Technology Data Exchange (ETDEWEB)

    Vidovich, Mladen I., E-mail: miv@uic.edu

    2013-05-15

    A new dedicated cardiac ventriculography catheter was specifically designed for radial and upper arm arterial access approach. Two catheter configurations have been developed to facilitate retrograde crossing of the aortic valve and to conform to various subclavian, ascending aortic and left ventricular anatomies. The “short” dedicated radial ventriculography catheter is suited for horizontal ascending aortas, obese body habitus, short stature and small ventricular cavities. The “long” dedicated radial ventriculography catheter is suited for vertical ascending aortas, thin body habitus, tall stature and larger ventricular cavities. This new design allows for improved performance, faster and simpler insertion in the left ventricle which can reduce procedure time, radiation exposure and propensity for radial artery spasm due to excessive catheter manipulation. Two different catheter configurations allow for optimal catheter selection in a broad range of patient anatomies. The catheter is exceptionally stable during contrast power injection and provides equivalent cavity opacification to traditional femoral ventriculography catheter designs.

  9. Incidence of catheter-related complications in patients with central venous or hemodialysis catheters: a health care claims database analysis.

    Science.gov (United States)

    Napalkov, Pavel; Felici, Diana M; Chu, Laura K; Jacobs, Joan R; Begelman, Susan M

    2013-10-16

    Central venous catheter (CVC) and hemodialysis (HD) catheter usage are associated with complications that occur during catheter insertion, dwell period, and removal. This study aims to identify and describe the incidence rates of catheter-related complications in a large patient population in a United States-based health care claims database after CVC or HD catheter placement. Patients in the i3 InVision DataMart® health care claims database with at least 1 CVC or HD catheter insertion claim were categorized into CVC or HD cohorts using diagnostic and procedural codes from the US Renal Data System, American College of Surgeons, and American Medical Association's Physician Performance Measures. Catheter-related complications were identified using published diagnostic and procedural codes. Incidence rates (IRs)/1000 catheter-days were calculated for complications including catheter-related bloodstream infections (CRBSIs), thrombosis, embolism, intracranial hemorrhage (ICH), major bleeding (MB), and mechanical catheter-related complications (MCRCs). Thirty percent of the CVC cohort and 54% of the HD cohort had catheter placements lasting <90 days. Catheter-related complications occurred most often during the first 90 days of catheter placement. IRs were highest for CRBSIs in both cohorts (4.0 [95% CI, 3.7-4.3] and 5.1 [95% CI, 4.7-5.6], respectively). Other IRs in CVC and HD cohorts, respectively, were thrombosis, 1.3 and 0.8; MCRCs, 0.6 and 0.7; embolism, 0.4 and 0.5; MB, 0.1 and 0.3; and ICH, 0.1 in both cohorts. Patients with cancer at baseline had significantly higher IRs for CRBSIs and thrombosis than non-cancer patients. CVC or HD catheter-related complications were most frequently seen in patients 16 years or younger. The risk of catheter-related complications is highest during the first 90 days of catheter placement in patients with CVCs and HD catheters and in younger patients (≤16 years of age) with HD catheters. Data provided in this study can be applied

  10. Modeling correlation indices between bladder and Foley′s catheter balloon dose with CT-based planning using limited CT slices in intracavitary brachytherapy for carcinoma of cervix

    Directory of Open Access Journals (Sweden)

    Oinam Arun

    2008-01-01

    Full Text Available Purpose: To derive and validate an index to correlate the bladder dose with the catheter balloon dose using limited computed tomography (CT slices. Materials and Methods: Applicator geometry reconstructed from orthogonal radiographs were back-projected on CT images of the same patients for anatomy-based dosimetric evaluation. The correlation indices derived using power function of the catheter balloon dose and the bladder volume dose were validated in 31 patients with cervical cancer. Results: There was significant correlation between International Commission on Radiation Units (ICRU-38 balloon reference dose (Dr and the dose received by 25% bladder volume (D 25 (P < 0.0001. Significant correlation was also found between the reference dose of mid-balloon point (D rm and the dose to D 25 (P < 0.0001. Average percentage difference [100 x (observed index - expected index / expected index] of observed value of I′ 25 (index for the dose to D25 bladder with respect to mid-balloon reference point from that of expected value was 0.52%, when the index was modeled with reference dose alone. Similarly the average percentage difference for I′10cc (index for the dose to 10 cc volume of bladder with respect to mid balloon point was 0.84%. When this index was modeled with absolute bladder volume and reference dose, standard deviation of the percentage difference between observed and expected index for D rm reduced by approximately 2% when compared to D r . Conclusion: For clinical applications, correlation index modeled with reference dose and volume predicts dose to absolute volume of bladder. Correlation index modeled with reference dose gives a good estimate of dose to relative bladder volume. From our study, we found D rm to be a better indicator of bladder dose than D r .

  11. In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study.

    Science.gov (United States)

    Waxman, Sergio; Dixon, Simon R; L'Allier, Philippe; Moses, Jeffrey W; Petersen, John L; Cutlip, Donald; Tardif, Jean-Claude; Nesto, Richard W; Muller, James E; Hendricks, Michael J; Sum, Stephen T; Gardner, Craig M; Goldstein, James A; Stone, Gregg W; Krucoff, Mitchell W

    2009-07-01

    To determine whether catheter-based near-infrared spectroscopy (NIRS) signals obtained with a novel catheter-based system from coronaries of patients are similar to those from autopsy specimens and to assess initial safety of NIRS device. An intravascular NIRS system for detection of lipid core-containing plaques (LCP) has been validated in human coronary autopsy specimens. The SPECTACL (SPECTroscopic Assessment of Coronary Lipid) trial was a parallel first-in-human multicenter study designed to demonstrate the applicability of the LCP detection algorithm in living patients. Intracoronary NIRS was performed in patients undergoing percutaneous coronary intervention. Acquired spectra were blindly compared with autopsy NIRS signals with multivariate statistics. To meet the end point of spectral similarity, at least two-thirds of the scans were required to have >80% of spectra similar to the autopsy spectra. A total of 106 patients were enrolled; there were no serious adverse events attributed to NIRS. Spectroscopic data could not be obtained in 17 (16%) patients due to technical limitations, leaving 89 patients for analysis. Spectra from 30 patients were unblinded to test the calibration of the LCP detection algorithm. Of the remaining 59 blinded cases, after excluding 11 due to inadequate data, spectral similarity was demonstrated in 40 of 48 spectrally adequate scans (83% success rate, 95% confidence interval: 70% to 93%, median spectral similarity/pullback: 96%, interquartile range 10%). The LCP was detected in 58% of 60 spectrally similar scans from both cohorts. This intravascular NIRS system safely obtained spectral data in patients that were similar to those from autopsy specimens. These results demonstrate the feasibility of invasive detection of coronary LCP with this novel system. (SPECTACL: SPECTroscopic Assessment of Coronary Lipid; NCT00330928).

  12. Uncalibrated continuous cardiac output measurement in liver transplant patients: LiDCOrapid™ system versus pulmonary artery catheter.

    Science.gov (United States)

    Costa, Maria Gabriella; Chiarandini, Paolo; Scudeller, Luigia; Vetrugno, Luigi; Pompei, Livia; Serena, Giovanni; Buttera, Stefania; Della Rocca, Giorgio

    2014-06-01

    The aim of the study was to assess the level of agreement between continuous cardiac output estimated by uncalibrated pulse-power analysis (PulseCOLiR) and intermittent (ICO) and continuous cardiac output (CCO) obtained using a pulmonary artery catheter (PAC). Prospective cohort study. University hospital intensive care unit. Twenty patients after liver transplantation. Pulmonary artery catheters were placed in all patients, and ICO and CCO were determined using thermodilution. PulseCOLiR measurements were made using a LiDCOrapid(TM) (LiDCO Ltd, Cambridge, UK). ICO data were determined after intensive care unit admission and every 8 hours until the 48th postoperative hour. CCO and PulseCOLiR measurements were recorded simultaneously at these same time intervals as well as hourly. For the 8-hour data set (140 data pairs), the mean bias and percentage errors (PE) were, respectively,-0.10 L/min and 39.2% for ICO versus PulseCOLiR and 0.79 L/min and 34.6% for CCO versus PulseCOLiR. For the hourly comparison of CCO versus PulseCOLiR (980 data pairs), the bias was 0.75 L/min and the PE 37%. To assess the ability to measure change, a 4-quadrant plot was produced for each pair of methods. The performance of PulseCOLiR was moderate in detecting changes in ICO. In conclusion, the uncalibrated PulseCOLir method should not be used as a substitute for the thermodilution technique for the monitoring of cardiac output in liver transplant patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Bladder Morphology Using 2 Different Catheter Designs

    Science.gov (United States)

    2017-04-10

    Urologic Injuries; Urologic Diseases; Bladder Infection; Urinary Tract Infections; Mucosal Inflammation; Mucosal Infection; Bladder Injury; Catheter-Related Infections; Catheter Complications; Catheter; Infection (Indwelling Catheter); Pelvic Floor Disorders; Urinary Incontinence

  14. In vitro catheter and sorbent-based method for clearance of radiocontrast material during cerebral interventions

    Energy Technology Data Exchange (ETDEWEB)

    Angheloiu, George O., E-mail: goangheloiu@drmc.org [Heart and Vascular Institute, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Department of Cardiology, Dubois Regional Medical Center, Dubois, PA (United States); Hänscheid, Heribert; Reiners, Christoph [Department of Nuclear Medicine, University of Würzburg, Würzburg (Germany); Anderson, William D. [Cardiology Department, Exempla Healthcare, Denver, CO (United States); Kellum, John A. [CRISMA Center, Department of Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA (United States)

    2013-07-15

    Background: Contrast-induced acute kidney injury is a severe condition resulting from the use of radiology contrast in patients with predisposing factors. Hypothesis: We hypothesized that a novel system including a device containing polymer resin sorbent beads and a custom-made suctioning catheter could efficiently remove contrast from an in vitro novel model of circulatory system (MOCS) mimicking the cerebral circulation. Methods: A custom-made catheter was built and optimized for cerebral venous approach. The efficiency of a system made of a polymer resin sorbent beads column (CST 401, Cytosorbents) and this particular catheter was tested in the MOCS running a solution composed of 0.9% saline and radio-contrast. During two series of 18 cycles of first-pass experiments we assessed the catheter's suctioning efficiency and the system's ability to clear radio-contrast injected into the MOCS's cerebral arterial segment. We also assessed the functioning and reliability of the MOCS. Results: Mean suctioning efficiency of the catheter was 84% ± 24%. The polymer sorbent column contrast removal rate was initially 96% and gradually decreased with subsequent cycles in a linear fashion during an experiment lasting approximately 90 minutes. The MOCS had a reliability of 0.9946×min{sup −1} where 1 × min{sup −1} was the optimum value. Conclusion: A system including a polymer resin sorbent beads column and a custom-made suctioning catheter had an excellent initial efficiency in quickly removing contrast from an artificial MOCS mimicking the cerebral circulation. MOCS is an inexpensive and relatively reliable custom-made system that can be used for training or testing purposes.

  15. In vitro catheter and sorbent-based method for clearance of radiocontrast material during cerebral interventions

    International Nuclear Information System (INIS)

    Angheloiu, George O.; Hänscheid, Heribert; Reiners, Christoph; Anderson, William D.; Kellum, John A.

    2013-01-01

    Background: Contrast-induced acute kidney injury is a severe condition resulting from the use of radiology contrast in patients with predisposing factors. Hypothesis: We hypothesized that a novel system including a device containing polymer resin sorbent beads and a custom-made suctioning catheter could efficiently remove contrast from an in vitro novel model of circulatory system (MOCS) mimicking the cerebral circulation. Methods: A custom-made catheter was built and optimized for cerebral venous approach. The efficiency of a system made of a polymer resin sorbent beads column (CST 401, Cytosorbents) and this particular catheter was tested in the MOCS running a solution composed of 0.9% saline and radio-contrast. During two series of 18 cycles of first-pass experiments we assessed the catheter's suctioning efficiency and the system's ability to clear radio-contrast injected into the MOCS's cerebral arterial segment. We also assessed the functioning and reliability of the MOCS. Results: Mean suctioning efficiency of the catheter was 84% ± 24%. The polymer sorbent column contrast removal rate was initially 96% and gradually decreased with subsequent cycles in a linear fashion during an experiment lasting approximately 90 minutes. The MOCS had a reliability of 0.9946×min −1 where 1 × min −1 was the optimum value. Conclusion: A system including a polymer resin sorbent beads column and a custom-made suctioning catheter had an excellent initial efficiency in quickly removing contrast from an artificial MOCS mimicking the cerebral circulation. MOCS is an inexpensive and relatively reliable custom-made system that can be used for training or testing purposes

  16. Management of hemodialysis catheter-related bacteremia with an adjunctive antibiotic lock solution.

    Science.gov (United States)

    Krishnasami, Zipporah; Carlton, Donna; Bimbo, Lisa; Taylor, Maria E; Balkovetz, Daniel F; Barker, Jill; Allon, Michael

    2002-03-01

    Tunneled dialysis catheters are complicated by frequent systemic infections. Standard therapy of catheter-associated bacteremia involves both systemic antibiotics and catheter replacement. Recent data suggest that biofilms in the catheter lumen are responsible for the bacteremia, and that instillation of an antibiotic lock (highly concentrated antibiotic solution) into the catheter lumen after dialysis sessions can eradicate the biofilm. We analyzed prospectively the efficacy of an antibiotic lock protocol, in conjunction with systemic antibiotics, for treatment of patients with dialysis catheter-associated bacteremia without catheter removal. Protocol success was defined as resolution of fever and negative surveillance cultures one week following completion of the protocol. Protocol failure was defined as persistence of fever or surveillance cultures positive for any pathogen. In addition, infection-free catheter survival was compared to that observed in institutional historical control patients treated with catheter replacement. Blood cultures were positive in 98 of 129 of episodes (76%) in which patients dialyzing with a catheter had fever or chills. Protocol success occurred in 40 of 79 infected patients (51%) treated with the antibiotic lock. Protocol failure occurred in 39 cases (49%): 7 had persistent fever, 15 had positive surveillance cultures (9 for Candida and 6 for bacteria), and 17 required catheter removal due to malfunction. Each of the pathogens in the surveillance cultures was different from the original pathogen in that patient. Eight of the 9 secondary Candida infections and all 6 secondary bacterial infections resolved after catheter exchange and specific antimicrobial treatment. Overall catheter survival with the antibiotic lock protocol was similar to that observed among patients managed with catheter replacement (median survival, 64 vs. 54 days, P = 0.24). Use of an antibiotic lock, in conjunction with systemic antibiotic therapy, can

  17. Remote control catheter navigation: options for guidance under MRI

    Directory of Open Access Journals (Sweden)

    Muller Leah

    2012-06-01

    Full Text Available Abstract Background Image-guided endovascular interventions have gained increasing popularity in clinical practice, and magnetic resonance imaging (MRI is emerging as an attractive alternative to X-ray fluoroscopy for guiding such interventions. Steering catheters by remote control under MRI guidance offers unique challenges and opportunities. Methods In this review, the benefits and limitations of MRI-guided remote control intervention are addressed, and the tools for guiding such interventions in the magnetic environment are summarized. Designs for remote control catheter guidance include a catheter tip electromagnetic microcoil design, a ferromagnetic sphere-tipped catheter design, smart material-actuated catheters, and hydraulically actuated catheters. Remote control catheter guidance systems were compared and contrasted with respect to visualization, safety, and performance. Performance is characterized by bending angles achievable by the catheter, time to achieve bending, degree of rotation achievable, and miniaturization capacity of the design. Necessary improvements for furthering catheter design, especially for use in the MRI environment, are addressed, as are hurdles that must be overcome in order to make MRI guided endovascular procedures more accessible for regular use in clinical practice. Conclusions MR-guided endovascular interventions under remote control steering are in their infancy due to issues regarding safety and reliability. Additional experimental studies are needed prior to their use in humans.

  18. Catheter ablation of epicardial ventricular tachycardia

    Directory of Open Access Journals (Sweden)

    Takumi Yamada, MD, PhD

    2014-08-01

    Full Text Available Ventricular tachycardias (VTs can usually be treated by endocardial catheter ablation. However, some VTs can arise from the epicardial surface, and their substrate can be altered only by epicardial catheter ablation. There are two approaches to epicardial catheter ablation: transvenous and transthoracic. The transvenous approach through the coronary venous system (CVS has been commonly used because it is easily accessible. However, this approach may be limited by the distribution of the CVS and insufficient radiofrequency energy delivery. Transthoracic epicardial catheter ablation has been developed to overcome these limitations of the transvenous approach. It is a useful supplemental or even preferred strategy to eliminate epicardial VTs in the electrophysiology laboratory. This technique has been applied for scar-related VTs secondary to often non-ischemic cardiomyopathy and sometimes ischemic cardiomyopathy, and idiopathic VTs as the epicardial substrates of these VTs have become increasingly recognized. When endocardial ablation and epicardial ablation through the CVS are unsuccessful, transthoracic epicardial ablation should be the next option. Intrapericardial access is usually obtained through a subxiphoidal pericardial puncture. This approach might not be possible in patients with pericardial adhesions caused by prior cardiac surgery or pericarditis. In such cases, a hybrid procedure involving surgical access with a subxiphoid pericardial window and a limited anterior or lateral thoracotomy might be a feasible and safe method of performing an epicardial catheter ablation in the electrophysiology laboratory. Potential complications associated with this technique include bleeding and collateral damage to the coronary arteries and phrenic nerve. Although the risk of these complications is low, electrophysiologists who attempt epicardial catheter ablation should know the complications associated with this technique, how to minimize their

  19. Indwelling Urethral Catheter Self-Care Preparedness Among ...

    African Journals Online (AJOL)

    Conclusion: These subjects were not properly assessed and assigned appropriate systems of nursing care. Nurses need to be clear about the content of their patient teaching in catheter care and assume full responsibility in teaching them. Key words: Indwelling urethral catheter, Self-care, Preparedness. [Jnl of College of ...

  20. Evaluation of the safety of latrogenic lntestinal perforation during placement of percutaneous drainage catheter in rabbit

    International Nuclear Information System (INIS)

    Lee, Choon Hyeong; Oh, Joo Hyung; Park, Ga Young; Shin, Hong Sub; Kim, In Sub; Yoon, Yup; Lee, Dong Ho; Ko, Young Tae; Choi, Woo Suk; Lim, Joo Won

    1996-01-01

    To evaluate the safety of transgression of the bowel during intraperitoneal percutaneous catheter placement in an animal model. Eight 8-F straight catheters were percutaneously inserted into the small and large bowel of eight rabbits. In four animals, the catheters were left in place until autopsy, whereas in the remaining four, the catheters were withdrawn five days after insertion. Autopsy was performed in all animals ten days after catheter placement, and gross and microscopic examination was carried out. Transgressing the bowel during intraperitoneal percutaneous catheter placement did not contribute to any clinically significant complications. At autopsy, there was no bowel leakage, peritonitis, or abscess, although peritoneal adhesions were found around the catheter tract. Although further study is warranted, our study with an animal model indicated that transgression of the intestine during percutaneous placement of an intraabdominal catheter did not produce significant complications

  1. Evaluation of the safety of latrogenic lntestinal perforation during placement of percutaneous drainage catheter in rabbit

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choon Hyeong; Oh, Joo Hyung; Park, Ga Young; Shin, Hong Sub; Kim, In Sub; Yoon, Yup; Lee, Dong Ho; Ko, Young Tae; Choi, Woo Suk; Lim, Joo Won [Kyunghee Univ. Hospital, Seoul (Korea, Republic of)

    1996-10-01

    To evaluate the safety of transgression of the bowel during intraperitoneal percutaneous catheter placement in an animal model. Eight 8-F straight catheters were percutaneously inserted into the small and large bowel of eight rabbits. In four animals, the catheters were left in place until autopsy, whereas in the remaining four, the catheters were withdrawn five days after insertion. Autopsy was performed in all animals ten days after catheter placement, and gross and microscopic examination was carried out. Transgressing the bowel during intraperitoneal percutaneous catheter placement did not contribute to any clinically significant complications. At autopsy, there was no bowel leakage, peritonitis, or abscess, although peritoneal adhesions were found around the catheter tract. Although further study is warranted, our study with an animal model indicated that transgression of the intestine during percutaneous placement of an intraabdominal catheter did not produce significant complications.

  2. The Polar Fluid Model for Blood Flow through a Tapered Artery with Overlapping Stenosis: Effects of Catheter and Velocity Slip

    Directory of Open Access Journals (Sweden)

    J. V. Ramana Reddy

    2015-01-01

    Full Text Available The blood flow through an overlapping clogged tapered artery in the presence of catheter is discussed. Since cholesterol deposition is resulting in the stenosis formation, velocity slip at the arterial wall is considered. The equations governing the fluid flow have been solved analytically under the assumption of the mild stenosis. The analysis with respect to various parameters arising out of fluid and geometry considered, on physiological parameters such as impedance and wall shear stress at the maximum height of the stenosis as well as across the entire length of the stenosis has been reported. A table summarizing the locations of extreme heights and the corresponding annular radii is provided. It is observed that the wall shear stress is the same at both the locations corresponding to the maximum height of the stenosis in case of nontapered artery while it varies in case of tapered artery. It is also observed that slip velocity and diverging tapered artery facilitate the fluid flow. Shear stress at the wall is increasing as micropolar parameter is decreasing and the trend is reversed in case of coupling number. The results obtained are validated by comparing them with the experimental and theoretical results.

  3. Catheter-related bloodstream infection.

    Science.gov (United States)

    Goede, Matthew R; Coopersmith, Craig M

    2009-04-01

    Catheter-related bloodstream infections (CR-BSIs) are a common, frequently preventable complication of central venous catheterization. CR-BSIs can be prevented by strict attention to insertion and maintenance of central venous catheters and removing unneeded catheters as soon as possible. Antiseptic- or antibiotic-impregnated catheters are also an effective tool to prevent infections. The diagnosis of CR-BSI is made largely based on culture results. CR-BSIs should always be treated with antibiotics, and except in rare circumstances the infected catheter needs to be removed.

  4. Experimental study of a closed-chest pulmonary embolism-reperfusion injury canine model by means of Swan-Ganz catheter

    International Nuclear Information System (INIS)

    Bao Na; Zhai Renyou Jiang Tao; Wang Yajie; Zheng Juan; Wang Chen

    2007-01-01

    Objective: To establish a closed-chest pulmonary embolism-reperfusion animal model by Swan-Ganz catheter and to explore the mechanisms of pulmonary embolism (PE)-reperfusion injury (RI). Methods: Experiments were made on 14 mongrel dogs, ranging in weight from 15 to 18 kg, anesthetized with 3% pentobarbital sodium. The dogs were intubated with I. D. 7 endotracheal tubes. Under sterile conditions, a 7 F Swan-Ganz catheter via the external jugular vein was positioned in the unilateral pulmonary diaphragmatic lobe (DL) artery. Occlusion/reperfusion of the DL artery was controlled with 1.2 ml diluted contrast agent filled into/drawn from the balloon. After the 24 h PE, the balloon was deflated to result in 4 h reperfusion of the DL. Measurements of blood gases and tumor necrosis factor-α (TNF-α)were made at normal condition, at 24 h PE and at 4 h reperfusion. Thin-section CT scans were performed at normal condition, 24 h PE, 30 rain, 1, 2, 3 and 4 h reperfusion, respectively. At the end of each experiment, tissue specimens of bilateral diaphragmatic lobes were obtained for both wet/dry (W/D) weight ratio and for pathological study. Results: Reperfusion pulmonary edema (RPE) was an acute, mixed, noncardiogenic edema that was observed in all 14 dogs who had been successfully established as PE/RI animal models. RPE demonstrated heterogeneous ground-glass opacifications that predominated in the areas distal to the recanalized vessels. It manifested pathologically as an edematous lung infihrated by inflammatory cells. The mean of PaO 2 and TNF-α of 4 h reperfusion was (81 ± 4) mm Hg( 1 mm Hg =0.133 kPa) and (16.0 ± 2.5)pg/ml, which were significantly different (P<0.05) from normal value [(96 ± 6)mm Hg and (13.9 ± 2.0) pg/ml]. The W/D of the injured lung (6.3 ± 1.2) was significantly greater (P<0.01) than that of the contralateral lung (4.5 ± 1.2), suggesting that the increase in the lung water was due to reperfusion injury. Conclusion: The closed-chest canine model

  5. Comparison of Standard Catheters Versus Radial Artery-Specific Catheter in Patients Who Underwent Coronary Angiography Through Transradial Access.

    Science.gov (United States)

    Chen, On; Goel, Sunny; Acholonu, Michael; Kulbak, Guy; Verma, Shivani; Travlos, Efstratios; Casazza, Richard; Borgen, Elliot; Malik, Bilal; Friedman, Michael; Moskovits, Norbert; Frankel, Robert; Shani, Jacob; Ayzenberg, Sergey

    2016-08-01

    In this prospective, randomized controlled study, we aim to compare the performance outcomes of standard catheters with the radial artery-specific catheter. Over the past decade, transradial cardiac catheterization has gained widespread popularity because of its low complication rates compared with transfemoral access. Operators have the choice of using either standard catheters (used for both transfemoral and transradial approach, with need for separate catheter use for either right or left coronary artery engagement) or a dedicated radial artery catheter, which is specifically designed to engage both coronary arteries through radial artery access. A total of 110 consecutive patients who underwent coronary angiography at our institution from March 2015 to April 2015 were prospectively randomized to either radial artery-specific Tiger catheter (5Fr; Terumo Interventional Systems, Somerset, New Jersey) versus standard Judkins left and right catheters (5Fr R4, L4; Cordis Corporation, Miami, Florida). The end points of the study included fluoroscopy time, dose-area product, contrast volume used, and total procedure time for the coronary angiography. A total of 57 patients (52%) were randomized to radial artery-specific catheter and 53 (48%) to the standard catheter. Tiger catheter was associated with significantly lower fluoroscopy time (184 ± 91 vs 238 ± 131 seconds, p = 0.015), which was statistically significant. Other outcome measures such as dose-area product (2,882.4 ± 1,471.2 vs 3,524.6 ± 2,111.7 Gy·cm(2), p = 0.07), total contrast volume (48.1 ± 16.1 vs 53.4 ± 18.5 ml, p = 0.114), and total procedure time (337 ± 382 vs 434 ± 137 seconds, p = 0.085) were also lower in single-catheter group, but it did not reach statistical significance. A total of 8 patients (14%) were crossed over from radial-specific catheter arm to standard catheter arm because of substandard image quality and difficulty in coronary engagement. Six patients had to be

  6. Catheter-directed Intraportal Delivery of Endothelial Cell Therapy for Liver Regeneration: A Feasibility Study in a Large-Animal Model of Cirrhosis.

    Science.gov (United States)

    Lee, Kyungmouk Steve; Santagostino, Sara F; Li, David; Ramjit, Amit; Serrano, Kenneth; Ginsberg, Michael D; Ding, Bi-Sen; Rafii, Shahin; Madoff, David C

    2017-10-01

    Purpose To demonstrate the feasibility of imaging-guided catheter-directed delivery of endothelial cell therapy in a porcine model of cirrhosis for liver regeneration. Materials and Methods After approval from the institutional animal care and use committee, autologous liver endothelial cells were grown from core hepatic specimens from swine. Cirrhosis was induced in swine by means of transcatheter infusion of ethanol and iodized oil into the hepatic artery. Three weeks after induction of cirrhosis, the swine were randomly assigned to receive autologous cell therapy (endothelial cells, n = 4) or control treatment (phosphate-buffered saline, n = 4) by means of imaging-guided transhepatic intraportal catheterization. Fluorescence-activated cell sorting analysis was performed on biopsy samples 1 hour after therapy. Three weeks after intraportal delivery of endothelial cells, the swine were euthanized and the explanted liver underwent quantitative pathologic examination. Statistical analysis was performed with an unpaired t test by using unequal variance. Results Liver endothelial cells were successfully isolated, cultured, and expanded from eight 20-mm, 18-gauge hepatic core samples to 50 × 10 6 autologous cells per pig. Intraportal delivery of endothelial cell therapy or saline was technically successful in all eight swine, with no complications. Endothelial cells were present in the liver for a minimum of 1 hour after intraportal infusion. Swine treated with endothelial cell therapy showed mean levels of surrogate markers of hepatobiliary injury that were consistent with decreases in hepatic fibrosis and biliary ductal damage relative to the control animals, although statistical significance was not met in this pilot study: The mean percentage of positive pixels at Masson trichrome staining was 7.28% vs 5.57%, respectively (P = .20), the mean proliferation index with cytokeratin wide-spectrum was 2.55 vs 1.13 (P = .06), and the mean proliferation index with Ki67

  7. Virtual ablation for atrial fibrillation in personalized in-silico three-dimensional left atrial modeling: comparison with clinical catheter ablation.

    Science.gov (United States)

    Hwang, Minki; Kwon, Soon-Sung; Wi, Jin; Park, Mijin; Lee, Hyun-Seung; Park, Jin-Seo; Lee, Young-Seon; Shim, Eun Bo; Pak, Hui-Nam

    2014-09-01

    Although catheter ablation is an effective rhythm control strategy for atrial fibrillation (AF), empirically-based ablation has a substantial recurrence rate. The purposes of this study were to develop a computational platform for patient-specific virtual AF ablation and to compare the anti-fibrillatory effects of 5 different virtual ablation protocols with empirically chosen clinical ablations. We included 20 patients with AF (65% male, 60.1 ± 10.5 years old, 80% persistent AF [PeAF]) who had undergone empirically-based catheter ablation: circumferential pulmonary vein isolation (CPVI) for paroxysmal AF (PAF) and additional posterior box lesion (L1) and anterior line (L2) for PeAF. Using patient-specific three-dimensional left atrial (LA) geometry, we generated a finite element model and tested the AF termination rate after 5 different virtual ablations: CPVI alone, CPVI + L1, CPVI + L1,2, CPVI with complex fractionated atrial electrogram (CFAE) ablation, and CFAE ablation alone. 1. Virtual CPVI + L1,2 ablation showed the highest AF termination rate in overall patients (55%) and PeAF patients (n = 16, 62.5%). 2. The virtual AF maintenance duration was shortest in the case of virtual CPVI + L1,2 ablation in overall patients (2.19 ± 1.28 vs. 2.91 ± 1.04 s, p = 0.009) and in patients with PeAF (2.05 ± 1.23 vs. 2.93 ± 10.2 s, p = 0.004) compared with other protocols. Virtual AF ablation using personalized in-silico model of LA is feasible. Virtual ablation with CPVI + L1,2 shows the highest antifibrillatory effect, concordant with the empirical ablation protocol in patients with PeAF. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Spontaneous rotation of the monorail-type guide extension support catheter during advancement of a curved guiding catheter: the potential hazard of twisting with the coronary guidewire.

    Science.gov (United States)

    Hashimoto, Sho; Takahashi, Akihiko; Yamada, Takeshi; Mizuguchi, Yukio; Taniguchi, Norimasa; Hata, Tetsuya; Nakajima, Shunsuke

    2017-11-20

    The extension support guiding catheter has been used to perform complex percutaneous coronary intervention to increase back-up support for the guiding catheter or to ensure deep intubation for device delivery. However, because of its monorail design, advancement of the stent into the distal extension tubing segment is sometimes problematic. Although this problem is considered due to simple collision of the stent, operators have observed tangling between a monorail extension catheter and coronary guidewire in some patients. To examine movement of the collar of the extension guide catheter during advancement of the guiding catheter, we set up an in vitro model in which the guiding catheter had two curves. Rotation of the extension guide catheter was examined by both fluoroscopic imaging and movement of the hub of the proximal end of the catheter. During advancement in the first curve, the collar moved toward the outer side of the curve of the guiding catheter as the operator pushed the shaft of the extension guiding catheter, which overrode the guidewire. After crossing the first curve, the collar moved again to the outer side of the second curve (the inner side of the first curve) of the mother catheter, and then, another clockwise rotation was observed in the proximal hub. Consequently, the collar and tubing portion of the extension guide catheter rotated 360° around the coronary guidewire, and the monorail extension catheter and guidewire became tangled. There is a potential risk of unintentional twisting with the guidewire during advancement into the curved guiding catheter because of its monorail design.

  9. Modeling of System Families

    National Research Council Canada - National Science Library

    Feiler, Peter

    2007-01-01

    .... The Society of Automotive Engineers (SAE) Architecture Analysis & Design Language (AADL) is an industry-standard, architecture-modeling notation specifically designed to support a component- based approach to modeling embedded systems...

  10. Modelling Railway Interlocking Systems

    DEFF Research Database (Denmark)

    Lindegaard, Morten Peter; Viuf, P.; Haxthausen, Anne Elisabeth

    2000-01-01

    In this report we present a model of interlocking systems, and describe how the model may be validated by simulation. Station topologies are modelled by graphs in which the nodes denote track segments, and the edges denote connectivity for train traÆc. Points and signals are modelled by annotatio...

  11. Ablation of typical atrial flutter using a non-fluoroscopic catheter tracking system vs. conventional fluoroscopy--results from a prospective randomized study.

    Science.gov (United States)

    Schoene, Katharina; Rolf, Sascha; Schloma, Denis; John, Silke; Arya, Arash; Dinov, Borislav; Richter, Sergio; Bollmann, Andreas; Hindricks, Gerhard; Sommer, Philipp

    2015-07-01

    Reduction of radiation exposure using a sensor-based non-fluoroscopic catheter tracking (NFCT) system (MediGuide™, St Jude Medical, Inc.) was recently demonstrated by retrospective comparisons. We aimed to prospectively compare the effects of using NFCT vs. standard fluoroscopy on procedural parameters in patients undergoing radiofrequency ablation of typical atrial flutter. We prospectively randomized 40 patients undergoing cavotricuspid isthmus ablation for typical atrial flutter to either NFCT (n = 20) or conventional fluoroscopy (CONV, n = 20). Procedural parameters such as fluoroscopy time, radiation dose, and procedure duration, as well as periprocedural complications were compared. There were no statistically significant differences in baseline characteristics between the two groups. Bidirectional isthmus block was achieved in all patients. Fluoroscopy time was significantly reduced in the NFCT group {0.3 [inter-quartile range (IQR) 0.2; 0.48] min} when compared with CONV [5.7 (IQR 4.2; 11.5) min] (P fluoroscopy in patients undergoing radiofrequency ablation of typical atrial flutter, NFCT significantly reduced both radiation dose and fluoroscopy time with no effects on procedural duration. These findings support the incorporation of NFCT in routine clinical use. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  12. Novel Antiseptic Urinary Catheters for Prevention of Urinary Tract Infections: Correlation of In Vivo and In Vitro Test Results▿

    Science.gov (United States)

    Hachem, Ray; Reitzel, Ruth; Borne, Agatha; Jiang, Ying; Tinkey, Peggy; Uthamanthil, Rajesh; Chandra, Jyotsna; Ghannoum, Mahmoud; Raad, Issam

    2009-01-01

    Urinary catheters are widely used for hospitalized patients and are often associated with high rates of urinary tract infection. We evaluated in vitro the antiadherence activity of a novel antiseptic Gendine-coated urinary catheter against several multidrug-resistant bacteria. Gendine-coated urinary catheters were compared to silver hydrogel-coated Foley catheters and uncoated catheters. Bacterial biofilm formation was assessed by quantitative culture and scanning electron microscopy. These data were further correlated to an in vivo rabbit model. We challenged 31 rabbits daily for 4 days by inoculating the urethral meatus with 1.0 × 109 CFU streptomycin-resistant Escherichia coli per day. In vitro, Gendine-coated urinary catheters reduced the CFU of all organisms tested for biofilm adherence compared with uncoated and silver hydrogel-coated catheters (P < 0.004). Scanning electron microscopy analysis showed that a thick biofilm overlaid the control catheter and the silver hydrogel-coated catheters but not the Gendine-coated urinary catheter. Similar results were found with the rabbit model. Bacteriuria was present in 60% of rabbits with uncoated catheters and 71% of those with silver hydrogel-coated catheters (P < 0.01) but not in those with Gendine-coated urinary catheters. No rabbits with Gendine-coated urinary catheters had invasive bladder infections. Histopathologic assessment revealed no differences in toxicity or staining. Gendine-coated urinary catheters were more efficacious in preventing catheter-associated colonization and urinary tract infections than were silver hydrogel-coated Foley catheters and uncoated catheters. PMID:19805562

  13. Bilateral catheter-directed thrombolysis in a patient with deep venous thrombosis caused by a hypoplastic inferior vena cava

    NARCIS (Netherlands)

    Sloot, S.; Van Nierop, J.; Kootstra, J. J.; Wittens, C.; Fritschy, W. M.

    Introduction Deep venous thrombosis treatment using catheter-directed thrombolysis is advocated over systemic thrombolysis because it reduces bleeding complications. With the development of a catheter that combines ultrasound vibrations and the local delivering of thrombolytics, new and safer

  14. High definition urethral pressure profilometry: Evaluating a novel microtip catheter.

    Science.gov (United States)

    Klünder, Mario; Amend, Bastian; Vaegler, Martin; Kelp, Alexandra; Feuer, Ronny; Sievert, Karl-Dietrich; Stenzl, Arnulf; Sawodny, Oliver; Ederer, Michael

    2016-11-01

    Urethral pressure profilometry (UPP) is used in the diagnosis of stress urinary incontinence (SUI). SUI is a significant medical, social, and economic problem, affecting about 12.5% of the population. A novel microtip catheter was developed for UPP featuring an inclination sensor and higher angular resolution compared to systems in clinical use today. Therewith, the location of each measured pressure sample can be determined and the spatial pressure distribution inside the urethra reconstructed. In order to assess the performance and plausibility of data from the microtip catheter, we compare it to data from a double balloon air charged system. Both catheters are used on sedated female minipigs. Data from the microtip catheter are processed through a signal reconstruction algorithm, plotted and compared against data from the air-charged catheter. The microtip catheter delivers results in agreement with previous comparisons of microtip and air-charged systems. It additionally provides a new level of detail in the reconstructed UPPs which may lead to new insights into the sphincter mechanism of minipigs. The ability of air-charged catheters to measure pressure circumferentially is widely considered a main advantage over microtip catheters. However, directional pressure readings can provide additional information on angular fluctuations in the urethral pressure distribution. It is shown that the novel microtip catheter in combination with a signal reconstruction algorithm delivers plausible data. It offers the opportunity to evaluate urethral structures, especially the sphincter, in context of the correct location within the anatomical location of the pelvic floor. Neurourol. Urodynam. 35:888-894, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. EM-navigated catheter placement for gynecologic brachytherapy: an accuracy study

    Science.gov (United States)

    Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

    2014-03-01

    Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and /or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems.

  16. Agile and Bright Intracardiac Catheters

    NARCIS (Netherlands)

    M. Pekař (Martin)

    2017-01-01

    markdownabstractIntracardiac imaging catheters represent unique instruments to diagnose and treat a diseased heart. While there are imminent advances in medical innovation, many of the commercially available imaging catheters are outdated. Some of them have been designed more than 20 years and

  17. A device for performing automated balloon catheter inflation ischemia studies.

    Science.gov (United States)

    Leavesley, Silas J; Ledkins, Whitley; Rocic, Petra

    2014-01-01

    Coronary collateral growth (arteriogenesis) is a physiological adaptive response to transient and repetitive occlusion of major coronary arteries in which small arterioles (native collaterals) with minimal to no blood flow remodel into larger conduit arteries capable of supplying adequate perfusion to tissue distal to the site of occlusion. The ability to reliably and reproducibly mimic transient, repetitive coronary artery occlusion (ischemia) in animal models is critical to the development of therapies to restore coronary collateral development in type II diabetes and the metabolic syndrome. Current animal models for repetitive coronary artery occlusion implement a pneumatic occluder (balloon) that is secured onto the surface of the heart with the suture, which is inflated manually, via a catheter connected to syringe, to effect occlusion of the left anterior descending coronary artery (LAD). This method, although effective, presents complications in terms of reproducibility and practicality. To address these limitations, we have designed a device for automated, transient inflation of balloon catheters in coronary artery occlusion models. This device allows repeated, consistent inflation (to either specified pressure or volume) and the capability for implementing very complex, month-long protocols. This system has significantly increased the reproducibility of coronary collateral growth studies in our laboratory, resulting in a significant decrease in the numbers of animals needed to complete each study while relieving laboratory personnel from the burden of extra working hours and enabling us to continue studies over periods when we previously could not. In this paper, we present all details necessary for construction and operation of the inflator. In addition, all of the components for this device are commercially available and economical (Table S1). It is our hope that the adoption of automated balloon catheter inflation protocols will improve the experimental

  18. A device for performing automated balloon catheter inflation ischemia studies.

    Directory of Open Access Journals (Sweden)

    Silas J Leavesley

    Full Text Available Coronary collateral growth (arteriogenesis is a physiological adaptive response to transient and repetitive occlusion of major coronary arteries in which small arterioles (native collaterals with minimal to no blood flow remodel into larger conduit arteries capable of supplying adequate perfusion to tissue distal to the site of occlusion. The ability to reliably and reproducibly mimic transient, repetitive coronary artery occlusion (ischemia in animal models is critical to the development of therapies to restore coronary collateral development in type II diabetes and the metabolic syndrome. Current animal models for repetitive coronary artery occlusion implement a pneumatic occluder (balloon that is secured onto the surface of the heart with the suture, which is inflated manually, via a catheter connected to syringe, to effect occlusion of the left anterior descending coronary artery (LAD. This method, although effective, presents complications in terms of reproducibility and practicality. To address these limitations, we have designed a device for automated, transient inflation of balloon catheters in coronary artery occlusion models. This device allows repeated, consistent inflation (to either specified pressure or volume and the capability for implementing very complex, month-long protocols. This system has significantly increased the reproducibility of coronary collateral growth studies in our laboratory, resulting in a significant decrease in the numbers of animals needed to complete each study while relieving laboratory personnel from the burden of extra working hours and enabling us to continue studies over periods when we previously could not. In this paper, we present all details necessary for construction and operation of the inflator. In addition, all of the components for this device are commercially available and economical (Table S1. It is our hope that the adoption of automated balloon catheter inflation protocols will improve the

  19. Next generation of ventricular catheters for hydrocephalus based on parametric designs.

    Science.gov (United States)

    Galarza, M; Giménez, A; Amigó, J M; Schuhmann, M; Gazzeri, R; Thomale, U; McAllister, J P

    2018-02-01

    The flow pattern of the cerebrospinal fluid is probably the most important factor related to obstruction of ventricular catheters during the normal treatment of hydrocephalus. To better comprehend the flow pattern, we have carried out a parametric study via numerical models of ventricular catheters. In previous studies, the flow was studied under steady and, recently, in pulsatile boundary conditions by means of computational fluid dynamics (CFD) in three-dimensional catheter models. This study aimed to bring in prototype models of catheter CFD flow solutions as well to introduce the theory behind parametric development of ventricular catheters. A preceding study allowed deriving basic principles which lead to designs with improved flow patterns of ventricular catheters. The parameters chosen were the number of drainage segments, the distances between them, the number and diameter of the holes on each segment, as well as their relative angular position. CFD results of previously unreleased models of ventricular catheter flow solutions are presented in this study. Parametric development guided new designs with better flow distribution while lowering the shear stress of the catheters holes. High-resolution 3D printed catheter solutions of three models and basic benchmark testing are introduced as well. The next generation of catheter with homogeneous flow patterns based on parametric designs may represent a step forward for the treatment of hydrocephalus, by possibly broadening their lifespan.

  20. Skin colonisation at the catheter exit site is strongly associated with catheter colonisation and catheter-related sepsis.

    Science.gov (United States)

    Ponnusamy, Vennila; Perperoglou, Aris; Venkatesh, Vidheya; Curley, Anna; Brown, Nicholas; Tremlett, Catherine; Clarke, Paul

    2014-12-01

    The commonest mode of catheter colonisation is via the extraluminal route with skin bacteria. Catheter-related sepsis causes significant mortality and morbidity in neonates. Our aim was to study the relationships between culture-positive catheter exit site skin swabs, percutaneous central venous catheter segments and blood to determine the magnitude of associations between exit site skin colonisation, catheter colonisation and catheter-related sepsis. In a prospective study, an exit site skin swab and three formerly in vivo catheter segments (proximal, middle and tip) were taken for culture at catheter removal. In those neonates who were clinically unwell at catheter removal, a peripheral blood culture was also collected. Univariate and multivariate analyses were used to study associations. Skin swabs were culture positive in 39 (21%) of 187 catheter removals. With a culture-positive skin swab, the risk of associated catheter colonisation was nearly eight times higher (OR: 7.84, 95% CI: 3.59-17.15) and the risk of definite catheter-related sepsis with the same organism was nearly 10 times higher (OR 9.86, 95% CI: 3.13-31.00). Culture-positive skin swabs from the catheter exit site were strongly associated with catheter colonisation and with definite catheter-related sepsis with the same organism. These data provide further evidence supporting catheter colonisation via the extraluminal route and highlight the importance of optimising skin disinfection before catheter insertion. ©2014 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  1. Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation, characterization and simulated use in an in vitro vessel model

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Svea, E-mail: svea.petersen@uni-rostock.de [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kaule, Sebastian [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Stein, Florian [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Minrath, Ingo; Schmitz, Klaus-Peter [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany); Kragl, Udo [Institute for Chemistry, Analytical and Technical Chemistry University of Rostock, Albert-Einstein-Straße 3a, 18059 Rostock (Germany); Sternberg, Katrin [Institute for Biomedical Engineering, University of Rostock, Friedrich-Barnewitz-Straße 4, 18119 Rostock (Germany)

    2013-10-15

    Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer. - Highlights: • We provide detailed in vitro data for definition of DCB coating requirements. • An in vitro vessel model for evaluating drug delivery from DCB is presented. • Innovative ionic liquid-based coatings for DCB are developed. • The coating shows low drug loss and efficient drug transfer.

  2. Novel paclitaxel-coated angioplasty balloon catheter based on cetylpyridinium salicylate: Preparation, characterization and simulated use in an in vitro vessel model

    International Nuclear Information System (INIS)

    Petersen, Svea; Kaule, Sebastian; Stein, Florian; Minrath, Ingo; Schmitz, Klaus-Peter; Kragl, Udo; Sternberg, Katrin

    2013-01-01

    Drug-coated balloons (DCB), which have emerged as therapeutic alternative to drug-eluting stents in percutaneous cardiovascular intervention, are well described with regard to clinical efficiency and safety within a number of clinical studies. In vitro studies elucidating the correlation of coating method and composition with DCB performance are however rare but considered important for the understanding of DCB requirements and the improvement of established DCB. In this context, we evaluated the applicability of a pipetting, dip-coating, and spray-coating process for the establishment of DCB based on paclitaxel (PTX) and the ionic liquid cetylpyridinium salicylate (Cetpyrsal) as novel innovative additive in three different compositions. Among tested methods and compositions, the pipetting process with 50 wt.% PTX resulted in most promising coatings as drug load was less controllable by the other processes and higher PTX contents led to considerable drug crystallization, as visualized by electron microscopy, accelerating PTX loss during short-term elution. Applying these conditions, homogeneous coatings could be applied on balloon catheter, whose simulated use in an in vitro vessel model revealed percental drug losses of 36 and 28% during transit and percental drug transfers of 12 and 40% under expansion for coatings applied in expanded and folded balloon condition, respectively. In comparison to literature values, these results support the high potential of Cetpyrsal as novel DCB matrix regarding low drug loss and efficient drug transfer. - Highlights: • We provide detailed in vitro data for definition of DCB coating requirements. • An in vitro vessel model for evaluating drug delivery from DCB is presented. • Innovative ionic liquid-based coatings for DCB are developed. • The coating shows low drug loss and efficient drug transfer

  3. Time and resources of peripherally inserted central catheter insertion procedures: a comparison between blind insertion/chest X-ray and a real time tip navigation and confirmation system

    Science.gov (United States)

    Tomaszewski, Kenneth J; Ferko, Nicole; Hollmann, Sarah S; Eng, Simona C; Richard, Howard M; Rowe, Lynn; Sproule, Susan

    2017-01-01

    Background The Sherlock 3CG™ Tip Confirmation System (TCS) provides real-time peripherally inserted central catheter (PICC) tip insertion information using passive magnetic navigation and patient cardiac electrical activity. It is an alternative tip confirmation method to fluoroscopy or chest X-ray for PICC tip insertion confirmation in adults. The purpose of this study was to evaluate time and cost of the Sherlock 3CG TCS and blind insertion with chest X-ray tip confirmation (BI/CXR) for PICC insertions. Methods A cross-sectional, observational Time and Motion study was conducted. Data were collected at four hospitals in the US. Two hospitals used Sherlock 3CG TCS and two hospitals used BI/CXR to place/confirm successful PICC tip location. Researchers observed PICC insertions, collecting data from the beginning (ie, PICC kit opening) to catheter tip confirmation (ie, released for intravenous [IV] therapy). An economic model was developed to project outcomes for a larger population. Results A total of 120 subjects were enrolled, with 60 subjects enrolled in each arm and 30 enrolled at each of the four US hospitals. The mean time from initiation of the PICC procedure to the time to release for IV therapy was 33.93 minutes in the Sherlock 3CG arm and 176.32 minutes in the BI/CXR arm (p PICC insertions using the Sherlock 3CG TCS, while 20% of subjects in the BI/CXR arm had a malposition. BI/CXR subjects had significantly more total malpositions (mean 0.23 vs. 0, p < 0.001). For a hypothetical population of 1,000 annual patients, adoption of Sherlock 3CG TCS was predicted to be cost saving compared with BI/CXR in all three analysis years. Conclusion The results from this study demonstrate that Sherlock 3CG TCS, when compared with BI/CXR, is a superior alternative with regard to time to release subject to therapy, malposition rates, and minimization of X-ray exposure. PMID:28223832

  4. RSMASS system model development

    International Nuclear Information System (INIS)

    Marshall, A.C.; Gallup, D.R.

    1998-01-01

    RSMASS system mass models have been used for more than a decade to make rapid estimates of space reactor power system masses. This paper reviews the evolution of the RSMASS models and summarizes present capabilities. RSMASS has evolved from a simple model used to make rough estimates of space reactor and shield masses to a versatile space reactor power system model. RSMASS uses unique reactor and shield models that permit rapid mass optimization calculations for a variety of space reactor power and propulsion systems. The RSMASS-D upgrade of the original model includes algorithms for the balance of the power system, a number of reactor and shield modeling improvements, and an automatic mass optimization scheme. The RSMASS-D suite of codes cover a very broad range of reactor and power conversion system options as well as propulsion and bimodal reactor systems. Reactor choices include in-core and ex-core thermionic reactors, liquid metal cooled reactors, particle bed reactors, and prismatic configuration reactors. Power conversion options include thermoelectric, thermionic, Stirling, Brayton, and Rankine approaches. Program output includes all major component masses and dimensions, efficiencies, and a description of the design parameters for a mass optimized system. In the past, RSMASS has been used as an aid to identify and select promising concepts for space power applications. The RSMASS modeling approach has been demonstrated to be a valuable tool for guiding optimization of the power system design; consequently, the model is useful during system design and development as well as during the selection process. An improved in-core thermionic reactor system model RSMASS-T is now under development. The current development of the RSMASS-T code represents the next evolutionary stage of the RSMASS models. RSMASS-T includes many modeling improvements and is planned to be more user-friendly. RSMASS-T will be released as a fully documented, certified code at the end of

  5. Treatment of catheter-related bacteraemia with an antibiotic lock protocol: effect of bacterial pathogen.

    Science.gov (United States)

    Poole, Christopher V; Carlton, Donna; Bimbo, Lisa; Allon, Michael

    2004-05-01

    The standard therapy of dialysis catheter-related bacteraemia involves both systemic antibiotics and catheter replacement. We reported recently that instillation of an antibiotic lock (highly concentrated antibiotic solution) into the catheter lumen after dialysis sessions, in conjunction with systemic antibiotics, can successfully treat many episodes of catheter-related bacteraemia without requiring catheter removal. The present study evaluated whether the likelihood of achieving a cure with this protocol depends on the type of pathogen. This was a historically controlled interventional study of an antibiotic lock protocol for the treatment of catheter-related bacteraemia. We analysed prospectively the likelihood of clinical cure (fever resolution and negative surveillance cultures) with an antibiotic lock protocol among patients with dialysis catheter-related bacteraemia. In addition, infection-free catheter survival was evaluated for up to 150 days, and compared with that observed among patients managed with routine catheter replacement. Overall, the antibiotic lock protocol was successful in 33 of 47 infected patients (70%) with catheter-related bacteraemia. The likelihood of a clinical cure was 87% for Gram-negative infections, 75% for Staphylococcus epidermidis infections, and only 40% for Staphylococcus aureus infections (P = 0.04). The median infection-free catheter survival with the antibiotic lock protocol was longer than that observed among patients with routine catheter replacement (154 vs 71 days, P = 0.02). The clinical success of an antibiotic lock protocol in eradicating catheter-related bacteraemia while salvaging the catheter is highly dependent on the bacterial pathogen. Thus, the overall success rate in an individual dialysis programme will depend on the relative frequencies of different bacterial pathogens.

  6. Time and resources of peripherally inserted central catheter insertion procedures: a comparison between blind insertion/chest X-ray and a real time tip navigation and confirmation system

    Directory of Open Access Journals (Sweden)

    Tomaszewski KJ

    2017-02-01

    Full Text Available Kenneth J Tomaszewski,1 Nicole Ferko,2 Sarah S Hollmann,2 Simona C Eng,3 Howard M Richard,4 Lynn Rowe,5 Susan Sproule6 1KJT Group, Inc., Honeoye Falls, NY, USA; 2Cornerstone Research Group, Inc., Burlington, ON, Canada; 3Department of Hospitalist/Inpatient Services, Peninsula Regional Medical Center, Salisbury, MD, USA; 4Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD, USA; 5Department of Research, Florida Hospital, Maitland, FL, USA; 6Department of Diagnostic Imaging, Unity Hospital, Rochester, NY, USA Background: The Sherlock 3CG™ Tip Confirmation System (TCS provides real-time peripherally inserted central catheter (PICC tip insertion information using passive magnetic navigation and patient cardiac electrical activity. It is an alternative tip confirmation method to fluoroscopy or chest X-ray for PICC tip insertion confirmation in adults. The purpose of this study was to evaluate time and cost of the Sherlock 3CG TCS and blind insertion with chest X-ray tip confirmation (BI/CXR for PICC insertions.Methods: A cross-sectional, observational Time and Motion study was conducted. Data were collected at four hospitals in the US. Two hospitals used Sherlock 3CG TCS and two hospitals used BI/CXR to place/confirm successful PICC tip location. Researchers observed PICC insertions, collecting data from the beginning (ie, PICC kit opening to catheter tip confirmation (ie, released for intravenous [IV] therapy. An economic model was developed to project outcomes for a larger population.Results: A total of 120 subjects were enrolled, with 60 subjects enrolled in each arm and 30 enrolled at each of the four US hospitals. The mean time from initiation of the PICC procedure to the time to release for IV therapy was 33.93 minutes in the Sherlock 3CG arm and 176.32 minutes in the BI/CXR arm (p < 0.001. No malpositions were observed for PICC insertions using the Sherlock 3CG TCS, while 20% of subjects in the BI

  7. Systemic resilience model

    International Nuclear Information System (INIS)

    Lundberg, Jonas; Johansson, Björn JE

    2015-01-01

    It has been realized that resilience as a concept involves several contradictory definitions, both for instance resilience as agile adjustment and as robust resistance to situations. Our analysis of resilience concepts and models suggest that beyond simplistic definitions, it is possible to draw up a systemic resilience model (SyRes) that maintains these opposing characteristics without contradiction. We outline six functions in a systemic model, drawing primarily on resilience engineering, and disaster response: anticipation, monitoring, response, recovery, learning, and self-monitoring. The model consists of four areas: Event-based constraints, Functional Dependencies, Adaptive Capacity and Strategy. The paper describes dependencies between constraints, functions and strategies. We argue that models such as SyRes should be useful both for envisioning new resilience methods and metrics, as well as for engineering and evaluating resilient systems. - Highlights: • The SyRes model resolves contradictions between previous resilience definitions. • SyRes is a core model for envisioning and evaluating resilience metrics and models. • SyRes describes six functions in a systemic model. • They are anticipation, monitoring, response, recovery, learning, self-monitoring. • The model describes dependencies between constraints, functions and strategies

  8. Selected System Models

    Science.gov (United States)

    Schmidt-Eisenlohr, F.; Puñal, O.; Klagges, K.; Kirsche, M.

    Apart from the general issue of modeling the channel, the PHY and the MAC of wireless networks, there are specific modeling assumptions that are considered for different systems. In this chapter we consider three specific wireless standards and highlight modeling options for them. These are IEEE 802.11 (as example for wireless local area networks), IEEE 802.16 (as example for wireless metropolitan networks) and IEEE 802.15 (as example for body area networks). Each section on these three systems discusses also at the end a set of model implementations that are available today.

  9. Review of advanced catheter technologies in radiation oncology brachytherapy procedures

    OpenAIRE

    Zhou J; Zamdborg L; Sebastian E

    2015-01-01

    Jun Zhou,1,2 Leonid Zamdborg,1 Evelyn Sebastian1 1Department of Radiation Oncology, Beaumont Health System, 2Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA Abstract: The development of new catheter and applicator technologies in recent years has significantly improved treatment accuracy, efficiency, and outcomes in brachytherapy. In this paper, we review these advances, focusing on the performance of catheter imaging and reconstruction techniques in brachytherapy ...

  10. Steam-deformed Judkins-left guiding catheter with use of the GuideLiner® catheter to deliver stents for anomalous right coronary artery

    Science.gov (United States)

    Kuno, Toshiki; Fujisawa, Taishi; Yamazaki, Hiroyuki; Motoda, Hiroyuki; Kodaira, Masaki; Numasawa, Yohei

    2015-01-01

    Objective: Percutaneous coronary intervention for anomalous right coronary artery (RCA) originating from the left coronary cusp is challenging because of our current inability to coaxially engage the guiding catheter. Methods: We report a case of an 88-year-old woman with non-ST segment elevation myocardial infarction, with an anomalous RCA origin. Using either the Judkins-Left catheter or Amplatz-Left catheter was difficult because of RCA ostium tortuosity. Thus, we used steam to deform the Judkins-Left catheter, but back-up support was insufficient to deliver the stent. Results: We used GuideLiner®, a novel pediatric catheter with rapid exchange/monorail systems, to enhance back-up support. Conclusions: We were able to successfully stent with both the deformed Judkins-Left guiding catheter and GuideLiner® for an anomalous RCA origin. PMID:27489700

  11. An efficient cardiac mapping strategy for radiofrequency catheter ablation with active learning.

    Science.gov (United States)

    Feng, Yingjing; Guo, Ziyan; Dong, Ziyang; Zhou, Xiao-Yun; Kwok, Ka-Wai; Ernst, Sabine; Lee, Su-Lin

    2017-07-01

    A major challenge in radiofrequency catheter ablation procedures is the voltage and activation mapping of the endocardium, given a limited mapping time. By learning from expert interventional electrophysiologists (operators), while also making use of an active-learning framework, guidance on performing cardiac voltage mapping can be provided to novice operators or even directly to catheter robots. A learning from demonstration (LfD) framework, based upon previous cardiac mapping procedures performed by an expert operator, in conjunction with Gaussian process (GP) model-based active learning, was developed to efficiently perform voltage mapping over right ventricles (RV). The GP model was used to output the next best mapping point, while getting updated towards the underlying voltage data pattern as more mapping points are taken. A regularized particle filter was used to keep track of the kernel hyperparameter used by GP. The travel cost of the catheter tip was incorporated to produce time-efficient mapping sequences. The proposed strategy was validated on a simulated 2D grid mapping task, with leave-one-out experiments on 25 retrospective datasets, in an RV phantom using the Stereotaxis Niobe ® remote magnetic navigation system, and on a tele-operated catheter robot. In comparison with an existing geometry-based method, regression error was reduced and was minimized at a faster rate over retrospective procedure data. A new method of catheter mapping guidance has been proposed based on LfD and active learning. The proposed method provides real-time guidance for the procedure, as well as a live evaluation of mapping sufficiency.

  12. Modeling cellular systems

    CERN Document Server

    Matthäus, Franziska; Pahle, Jürgen

    2017-01-01

    This contributed volume comprises research articles and reviews on topics connected to the mathematical modeling of cellular systems. These contributions cover signaling pathways, stochastic effects, cell motility and mechanics, pattern formation processes, as well as multi-scale approaches. All authors attended the workshop on "Modeling Cellular Systems" which took place in Heidelberg in October 2014. The target audience primarily comprises researchers and experts in the field, but the book may also be beneficial for graduate students.

  13. Colonization of peripheral intravascular catheters with biofilm ...

    African Journals Online (AJOL)

    Background: Biofilms often colonize catheters and contribute to catheter-related septicemia. However, predictors of catheter colonization by biofilms remain poorly defined. The aim of this study was to evaluate clinical factors that may be associated with biofilm colonization of catheters. Materials and Methods: A total of 54 ...

  14. Modelling of wastewater systems

    DEFF Research Database (Denmark)

    Bechmann, Henrik

    Oxygen Demand) flux and SS flux in the inlet to the WWTP. COD is measured by means of a UV absorption sensor while SS is measured by a turbidity sensor. These models include a description of the deposit of COD and SS amounts, respectively, in the sewer system, and the models can thus be used to quantify......In this thesis, models of pollution fluxes in the inlet to 2 Danish wastewater treatment plants (WWTPs) as well as of suspended solids (SS) concentrations in the aeration tanks of an alternating WWTP and in the effluent from the aeration tanks are developed. The latter model is furthermore used...... to analyze and quantify the effect of the Aeration Tank Settling (ATS) operating mode, which is used during rain events. Furthermore, the model is used to propose a control algorithm for the phase lengths during ATS operation. The models are mainly formulated as state space model in continuous time...

  15. Peripherally inserted central catheter - insertion

    Science.gov (United States)

    PICC - insertion ... A PICC is a long, thin tube (called a catheter) that goes into your body through a vein in ... into a large vein near your heart. The PICC helps carry nutrients and medicines into your body. ...

  16. Percutaneously inserted central catheter - infants

    Science.gov (United States)

    PICC - infants; PQC - infants; Pic line - infants; Per-Q cath - infants ... A percutaneously inserted central catheter (PICC) is a long, very thin, soft plastic tube that is put into a small blood vessel. This article addresses PICCs in ...

  17. Implementation of a chronic unilateral intraparenchymal drug delivery system in a swine model.

    Science.gov (United States)

    Kim, Inyong; Paek, Seungleal; Nelson, Brian D; Knight, Emily J; Marsh, Michael P; Bieber, Allan J; Bennet, Kevin E; Lee, Kendall H

    2014-04-30

    Systemic delivery of pharmacologic agents has led to many significant advances in the treatment of neurologic and psychiatric conditions. However, this approach has several limitations, including difficulty penetrating the blood-brain barrier and enzymatic degradation prior to reaching its intended target. Here, we describe the testing of a system allowing intraparenchymal (IPa) infusion of therapeutic agents directly to the appropriate anatomical targets, in a swine model. Five male pigs underwent 3.0T magnetic resonance (MR) guided placement of an IPa catheter into the dorso-medial putamen, using a combined system of the Leksell stereotactic arc, a Mayo-developed MRI-compatible pig head frame, and a custom-designed Fred Haer Company (FHC) delivery system. Our results show hemi-lateral coverage of the pig putamen is achievable from a single infusion point and that the volume of the bolus detected in each animal is uniform (1544±420mm(3)). The IPa infusion system is designed to isolate the intracranial catheter from bodily-induced forces while delivering drugs and molecules into the brain tissue by convection-enhanced delivery, with minimal-to-no catheter track backflow. This study presents an innovative IPa drug delivery system, which includes a sophisticated catheter and implantable pump designed to deliver drugs and various molecules in a precise and controlled manner with limited backflow. It also demonstrates the efficacy of the delivery system, which has the potential to radically impact the treatment of a wide range of neurologic conditions. Lastly, the swine model used here has certain advantages for translation into clinical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Modeling Complex Systems

    CERN Document Server

    Boccara, Nino

    2010-01-01

    Modeling Complex Systems, 2nd Edition, explores the process of modeling complex systems, providing examples from such diverse fields as ecology, epidemiology, sociology, seismology, and economics. It illustrates how models of complex systems are built and provides indispensable mathematical tools for studying their dynamics. This vital introductory text is useful for advanced undergraduate students in various scientific disciplines, and serves as an important reference book for graduate students and young researchers. This enhanced second edition includes: . -recent research results and bibliographic references -extra footnotes which provide biographical information on cited scientists who have made significant contributions to the field -new and improved worked-out examples to aid a student’s comprehension of the content -exercises to challenge the reader and complement the material Nino Boccara is also the author of Essentials of Mathematica: With Applications to Mathematics and Physics (Springer, 2007).

  19. Central Venous Catheter-Associated Deep Venous Thrombosis in Critically Ill Children.

    Science.gov (United States)

    Faustino, Edward Vincent S

    2018-02-01

    The presence of a central venous catheter and admission to the intensive care unit are the most important risk factors for deep venous thrombosis (DVT) in children. At least 18% of critically ill children with a catheter develop radiologically confirmed catheter-associated thrombosis. Clinically apparent thrombosis occurs in 3% of critically ill children with a catheter and is associated with 8 additional days of mechanical ventilation. Even when the thrombus is initially asymptomatic, 8 to 18% of critically ill children with catheter-associated thrombosis develop postthrombotic syndrome. Thrombosis is uncommon within 24 hours after insertion of a nontunneled catheter in critically ill children, but nearly all thrombi have developed by 4 days after insertion. Hypercoagulability during or immediately after insertion of the catheter plays an essential role in the development of thrombosis. Pharmacologic prophylaxis, including local anticoagulation with heparin-bonded catheter, has not been shown to reduce the risk of catheter-related thrombosis in children. Systemic anticoagulation in critically ill children started soon after the insertion of the catheter, however, may be beneficial. A multicenter clinical trial that is testing this hypothesis is currently underway. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  20. Modeling Complex Systems

    International Nuclear Information System (INIS)

    Schreckenberg, M

    2004-01-01

    This book by Nino Boccara presents a compilation of model systems commonly termed as 'complex'. It starts with a definition of the systems under consideration and how to build up a model to describe the complex dynamics. The subsequent chapters are devoted to various categories of mean-field type models (differential and recurrence equations, chaos) and of agent-based models (cellular automata, networks and power-law distributions). Each chapter is supplemented by a number of exercises and their solutions. The table of contents looks a little arbitrary but the author took the most prominent model systems investigated over the years (and up until now there has been no unified theory covering the various aspects of complex dynamics). The model systems are explained by looking at a number of applications in various fields. The book is written as a textbook for interested students as well as serving as a comprehensive reference for experts. It is an ideal source for topics to be presented in a lecture on dynamics of complex systems. This is the first book on this 'wide' topic and I have long awaited such a book (in fact I planned to write it myself but this is much better than I could ever have written it!). Only section 6 on cellular automata is a little too limited to the author's point of view and one would have expected more about the famous Domany-Kinzel model (and more accurate citation!). In my opinion this is one of the best textbooks published during the last decade and even experts can learn a lot from it. Hopefully there will be an actualization after, say, five years since this field is growing so quickly. The price is too high for students but this, unfortunately, is the normal case today. Nevertheless I think it will be a great success! (book review)

  1. Needle catheter duodenostomy: a technique for duodenal alimentation of birds.

    Science.gov (United States)

    Goring, R L; Goldman, A; Kaufman, K J; Roberts, C; Quesenberry, K E; Kollias, G V

    1986-11-01

    A technique for duodenal alimentation (needle catheter duodenostomy) of birds was developed, using the domestic pigeon (Columba livia) as the experimental model. A needle catheter was inserted into the descending duodenum of 5 pigeons and was secured to the body wall and dorsum of each bird. A liquid diet was administered daily (in equal amounts of 0, 4, 8, 12, and 16 hours) for 14 days without adverse effects. On day 15, the catheters were removed, and the birds immediately resumed normal consumption of a pigeon ration and water diet. Although 4 of the 5 birds had minor weight loss, dietary alterations probably could be used on an individual basis to alleviate this problem. After oral alimentation was resumed, the 5 birds exceeded their initial body weight within 7 days. Four weeks after catheter removal, positive-contrast radiographic evaluations indicated that the duodenum of each pigeon appeared normal. Needle catheter duodenostomy was a viable method of alimentation in the domestic pigeon. This technique should be applicable for other avian species requiring bypass of the upper gastrointestinal tract proximal to the region of catheter insertion in the duodenum.

  2. [A blind point of vent catheter: air aspiration].

    Science.gov (United States)

    Inui, K; Orita, H; Shimanuki, T; Fukasawa, M; Gotou, S; Nakamura, C; Washio, M

    1993-05-01

    We experienced a case of saphenous vein air embolism after coronary artery bypass graft, in which case we used vent catheter kept in the left atrium. Though it was considered that air bubbles were never aspirated through vent catheter, we speculated that the origin of air bubbles must be the vent catheter. And we made an experiment on the motion of air in the vent catheter using a model of left heart composed with soft reserver (atrium) and pulsatile pump (ventricle). When the pulsatile pump was arrest, the air bubbles were never aspirated from the vent catheter to the soft reserver even if we vented with strong negative pressure. But, when the pulsatile pump was in motion and the left atrium was vented with some negative pressure, some leaks of air bubbles were recognized. So we must pay much more attention to the degree of venting when the heart is in motion. Sometimes we use overpressure safety valve composed with vent catheter, but measured left atrial pressure showed that decreased left atrial pressure was only 2 mmHg. So its use should be restricted in the patients with good ventricular function.

  3. Reprocessing single-use cardiac catheters for interventional cardiology. A cost-minimization model for estimating potential saving at departmental scale and national level

    OpenAIRE

    Francesco Tessarolo; Marcello Disertori; Giovanni M. Guarrera; Stefano Capri; Giandomenico Nollo

    2009-01-01

    Background: The utilization of single-use percutaneous catheters (SUDs) is a common practice in interventional cardiology, but the increasing of cardiac interventions and the consequent economic load demand for assessing SUDs’ reuse. The study aimed at estimating the potential saving for Italian cardiology departments in the hypothesis that reprocessing and reuse of SUD is performed by guaranteeing safety and efficiency of the reconditioned device as high...

  4. Modeling the earth system

    Energy Technology Data Exchange (ETDEWEB)

    Ojima, D. [ed.

    1992-12-31

    The 1990 Global Change Institute (GCI) on Earth System Modeling is the third of a series organized by the Office for Interdisciplinary Earth Studies to look in depth at particular issues critical to developing a better understanding of the earth system. The 1990 GCI on Earth System Modeling was organized around three themes: defining critical gaps in the knowledge of the earth system, developing simplified working models, and validating comprehensive system models. This book is divided into three sections that reflect these themes. Each section begins with a set of background papers offering a brief tutorial on the subject, followed by working group reports developed during the institute. These reports summarize the joint ideas and recommendations of the participants and bring to bear the interdisciplinary perspective that imbued the institute. Since the conclusion of the 1990 Global Change Institute, research programs, nationally and internationally, have moved forward to implement a number of the recommendations made at the institute, and many of the participants have maintained collegial interactions to develop research projects addressing the needs identified during the two weeks in Snowmass.

  5. Placement peripherally inserted central catheters (PICC): the upper arm approach

    International Nuclear Information System (INIS)

    Choo, In Wook; Choo, Sung Wook; Choi, Dong Il; Yoon, Jung Hwan; Hwang, Jae Woong; Lim, Jae Hoon; Andrews, James C.; Williams, David M.; Cho, Kyung J.

    1995-01-01

    To evaluate a recently developed technique to place a medium-duration (weeks to months) central venous access. Within three-year period, 635 patients were referred to interventional radiology suite for placement of peripherally inserted central catheter (PICC). Contrast medium was injected into the peripheral intravenous line and a puncture was made into the opacified vein near the junction of the middle and upper thirds of the upper arm, either the brachial or basilic vein under fluoroscopic guidance. A 5.5-French peel-away sheath was inserted into the vein and a 5-French silicone catheter was introduced with its distal tip to the junction of the right atrium and superior vena cava. Catheter placement was successful in all patients unless there was a central venous obstruction. Catheters were maintained from 2 days to 5 months with a mean of 3 weeks. Complications included infection requiring removal of the PICC in 16 patients (2.5%), acute thrombosis of the subclavian vein in 3 (0.5%). Occluded catheters in 4 patients were easily cleared with urokinase in place. The PICC system is an excellent option for medium-duration central venous access. Patients were able to carry on normal activities with the catheters in place

  6. Placement peripherally inserted central catheters (PICC): the upper arm approach

    Energy Technology Data Exchange (ETDEWEB)

    Choo, In Wook; Choo, Sung Wook; Choi, Dong Il; Yoon, Jung Hwan; Hwang, Jae Woong; Lim, Jae Hoon [Samsung Medical Center, Seoul (Korea, Republic of); Andrews, James C. [Mayo Clinic, Lansing (United States); Williams, David M.; Cho, Kyung J. [University of Michigan Hospital, Lansing (United States)

    1995-10-15

    To evaluate a recently developed technique to place a medium-duration (weeks to months) central venous access. Within three-year period, 635 patients were referred to interventional radiology suite for placement of peripherally inserted central catheter (PICC). Contrast medium was injected into the peripheral intravenous line and a puncture was made into the opacified vein near the junction of the middle and upper thirds of the upper arm, either the brachial or basilic vein under fluoroscopic guidance. A 5.5-French peel-away sheath was inserted into the vein and a 5-French silicone catheter was introduced with its distal tip to the junction of the right atrium and superior vena cava. Catheter placement was successful in all patients unless there was a central venous obstruction. Catheters were maintained from 2 days to 5 months with a mean of 3 weeks. Complications included infection requiring removal of the PICC in 16 patients (2.5%), acute thrombosis of the subclavian vein in 3 (0.5%). Occluded catheters in 4 patients were easily cleared with urokinase in place. The PICC system is an excellent option for medium-duration central venous access. Patients were able to carry on normal activities with the catheters in place.

  7. Virtual In-Silico Modeling Guided Catheter Ablation Predicts Effective Linear Ablation Lesion Set for Longstanding Persistent Atrial Fibrillation: Multicenter Prospective Randomized Study.

    Science.gov (United States)

    Shim, Jaemin; Hwang, Minki; Song, Jun-Seop; Lim, Byounghyun; Kim, Tae-Hoon; Joung, Boyoung; Kim, Sung-Hwan; Oh, Yong-Seog; Nam, Gi-Byung; On, Young Keun; Oh, Seil; Kim, Young-Hoon; Pak, Hui-Nam

    2017-01-01

    Objective: Radiofrequency catheter ablation for persistent atrial fibrillation (PeAF) still has a substantial recurrence rate. This study aims to investigate whether an AF ablation lesion set chosen using in-silico ablation (V-ABL) is clinically feasible and more effective than an empirically chosen ablation lesion set (Em-ABL) in patients with PeAF. Methods: We prospectively included 108 patients with antiarrhythmic drug-resistant PeAF (77.8% men, age 60.8 ± 9.9 years), and randomly assigned them to the V-ABL ( n = 53) and Em-ABL ( n = 55) groups. Five different in-silico ablation lesion sets [1 pulmonary vein isolation (PVI), 3 linear ablations, and 1 electrogram-guided ablation] were compared using heart-CT integrated AF modeling. We evaluated the feasibility, safety, and efficacy of V-ABL compared with that of Em-ABL. Results: The pre-procedural computing time for five different ablation strategies was 166 ± 11 min. In the Em-ABL group, the earliest terminating blinded in-silico lesion set matched with the Em-ABL lesion set in 21.8%. V-ABL was not inferior to Em-ABL in terms of procedure time ( p = 0.403), ablation time ( p = 0.510), and major complication rate ( p = 0.900). During 12.6 ± 3.8 months of follow-up, the clinical recurrence rate was 14.0% in the V-ABL group and 18.9% in the Em-ABL group ( p = 0.538). In Em-ABL group, clinical recurrence rate was significantly lower after PVI+posterior box+anterior linear ablation, which showed the most frequent termination during in-silico ablation (log-rank p = 0.027). Conclusions: V-ABL was feasible in clinical practice, not inferior to Em-ABL, and predicts the most effective ablation lesion set in patients who underwent PeAF ablation.

  8. Flow characteristics of urethral catheters of the same caliber vary between manufacturers.

    Science.gov (United States)

    Stewart, Carrie A; Yamaguchi, Eiichiro; Teixeira Vaz, Jessica; Gaver, Donald P; Ortenberg, Joseph

    2017-08-01

    Clean intermittent catheterization (CIC) is frequently prescribed for bladder dysfunction, either per urethra or via a continent catheterizable channel. Small catheters may be required for infants or continent channels. Success with CIC is highly dependent upon patient and family compliance. The urinary flow rate through the catheter is an important factor, which can decrease CIC time and improve quality of life. There is little objective information regarding flow rate through urinary catheters to guide catheter recommendation or prescription. Clinically, we noted that there was a difference in flow among catheter brands, and we questioned if catheters of the same-labeled diameter exhibit the same flow characteristics, which could have implications for catheter selection. Twenty-one commercially available male pediatric urinary catheters from nine brands were tested (11 straight tip, 10 coude tip). Nine of the 21 tested catheters had a hydrophilic coating. All tested catheters shared a 10F outer diameter. For each, microscopic imaging and a precision caliper were used to measure the inner diameter and tip inlet area. A hydraulic system modified from ASTM standard testing specifications was used to simulate bladder catheterization. Measurement of each catheter was repeated five times using three different static hydraulic pressures (20, 40 and 50 cmH 2 O). Catheter flow rate and structural measurements were identified and the fastest and slowest of the catheters are presented in the table. The variable flow rates between brands were due to the differences in catheter structural characteristics such as the inner diameter (ID) and the tip inlet area to inner lumen area ratio (AR). The maximum variation of flow rate of all tested 10F catheters was 48%, ID varied up to 22%, from 1.71 to 2.11 mm or 5.13-6.33F. AR varied up to 166%. The table delineates the fastest and slowest rates at three measured pressures. The outer diameter labeled 10F on packaging was true to

  9. A Three-Dimensional Shape-Based Force and Stiffness-Sensing Platform for Tendon-Driven Catheters.

    Science.gov (United States)

    Kouh Soltani, Minou; Khanmohammadi, Sohrab; Ghalichi, Farzan

    2016-06-28

    This paper presents an efficient shape-based three-axial force and stiffness estimator for active catheters commonly implemented in cardiac ablation. The force-sensing capability provides important feedback for catheterization procedures including real-time control and catheter steering in autonomous navigation systems. The proposed platform is based on the introduced accurate and computationally efficient Cosserat rod model for tendon-driven catheters. The proposed nonlinear Kalman filter formulation for contact force estimation along with the developed catheter model provides a real-time force observer robust to nonlinearities and noise covariance uncertainties. Furthermore, the proposed platform enables stiffness estimation in addition to tip contact force sensing in different operational circumstances. The approach incorporates pose measurements which can be achieved using currently developed pose-sensing systems or imaging techniques. The method makes the approach compatible with the range of forces applied in clinical applications. The simulation and experimental results verify the viability of the introduced force and stiffness-sensing technique.

  10. A Three-Dimensional Shape-Based Force and Stiffness-Sensing Platform for Tendon-Driven Catheters

    Directory of Open Access Journals (Sweden)

    Minou Kouh Soltani

    2016-06-01

    Full Text Available This paper presents an efficient shape-based three-axial force and stiffness estimator for active catheters commonly implemented in cardiac ablation. The force-sensing capability provides important feedback for catheterization procedures including real-time control and catheter steering in autonomous navigation systems. The proposed platform is based on the introduced accurate and computationally efficient Cosserat rod model for tendon-driven catheters. The proposed nonlinear Kalman filter formulation for contact force estimation along with the developed catheter model provides a real-time force observer robust to nonlinearities and noise covariance uncertainties. Furthermore, the proposed platform enables stiffness estimation in addition to tip contact force sensing in different operational circumstances. The approach incorporates pose measurements which can be achieved using currently developed pose-sensing systems or imaging techniques. The method makes the approach compatible with the range of forces applied in clinical applications. The simulation and experimental results verify the viability of the introduced force and stiffness-sensing technique.

  11. Systemic thrombolysis increases hemorrhagic stroke risk without survival benefit compared with catheter-directed intervention for the treatment of acute pulmonary embolism.

    Science.gov (United States)

    Liang, Nathan L; Avgerinos, Efthymios D; Singh, Michael J; Makaroun, Michel S; Chaer, Rabih A

    2017-03-01

    Systemic thrombolysis (ST) and catheter-directed intervention (CDI) are both used in the treatment of acute pulmonary embolism (PE), but the comparative outcomes of these two therapies remain unclear. The objective of this study was to compare short-term mortality and safety outcomes between the two treatments using a large national database. Patients presenting with acute PE were identified in the National Inpatient Sample (NIS) from 2009 to 2012. Comorbidities, clinical characteristics, and invasive procedures were identified using International Classification of Diseases, Ninth Revision (ICD) codes and the Elixhauser comorbidity index. To adjust for anticipated baseline differences between the two treatment groups, propensity score matching was used to create a matched ST cohort with clinical and comorbid characteristics similar to those of the CDI cohort. Subgroups of patients with and without hemodynamic shock were analyzed separately. Primary outcomes were in-hospital mortality, overall bleeding risk, and hemorrhagic stroke risk. Of 263,955 subjects with acute PE, 1.63% (n = 4272) received ST and 0.55% (n = 1455) received CDI. ST subjects were older, had more chronic comorbidities, and had higher rates of respiratory failure (ST, 27.9% [n = 1192]; CDI, 21.2% [n = 308]; P hemorrhagic stroke rates (ST, 2.2% [n = 96]; CDI, 1.4% [n = 20]; P = .041). After propensity matching, 1430 patients remained in each cohort; baseline characteristics of the matched cohorts did not differ significantly using standardized difference comparisons. Analysis of the matched cohorts did not demonstrate a significant effect of CDI on in-hospital mortality or overall bleeding risk but did show a significant protective effect against hemorrhagic stroke compared with ST (odds ratio, 0.47; 95% confidence interval, 0.27-0.82; P = .01). Subgroup analysis showed decreased odds of hemorrhagic stroke for CDI in the nonshock subgroup and increased procedural bleeding for CDI but no

  12. Intracorporeal knotting of a femoral nerve catheter

    Directory of Open Access Journals (Sweden)

    Ghanem, Mohamed

    2015-01-01

    Full Text Available Peripheral nerve catheters are effective and well-established tools to provide postoperative analgesia to patients undergoing orthopedic surgery. The performance of these techniques is usually considered safe. However, placement of nerve catheters may be associated with a considerable number of side effects and major complications have repeatedly been published. In this work, we report on a patient who underwent total knee replacement with spinal anesthesia and preoperative insertion of femoral and sciatic nerve catheters for postoperative analgesia. During insertion of the femoral catheter, significant resistance was encountered upon retracting the catheter. This occurred due to knotting of the catheter. The catheter had to be removed by operative intervention which has to be considered a major complication. The postoperative course was uneventful. The principles for removal of entrapped peripheral catheters are not well established, may differ from those for neuroaxial catheters, and range from cautious manipulation up to surgical intervention.

  13. Influence of drainage conditions on mucosal bladder damage by indwelling catheters. I. Pressure study.

    Science.gov (United States)

    Glahn, B E

    1988-01-01

    Clinical observations suggest the occurrence of a hydro-dynamically generated negative pressure wave in termination of bladder evacuation in patients with an intermittently clamped indwelling catheter. This in-vitro study confirmed the assumption. At circumstances like those of a bedridden person with a conventional urinary drainage system the transitory suction at the site of the catheter eyes reaches negative peak pressures of about 150-180 cm of water when catheters on a latex base are used and about 300-350 cm by catheters of 100% silicone, which is a less compliant (elastic) material. Catheters, drainage tubes and the combined function were analyzed regarding factors influencing this hydro-dynamical phenomenon, which may occur in some situations of straight drainage too. Clinical aspects are discussed. A noxious effect on the bladder mucosa is demonstrated in a subsequent study. It is concluded that the basal hydro-physical laws involved in bladder drainage by indwelling catheter need more attention.

  14. Less leakage and dislodgement with a catheter-over-needle versus a catheter-through-needle approach for peripheral nerve block: an ex vivo study.

    Science.gov (United States)

    Tsui, Ban C H; Tsui, Jenkin

    2012-07-01

    The objective of this study was to compare the catheter-through-needle (CTN) and catheter-over-needle (CON) catheterization techniques ex vivo by measuring leak pressure around the catheter and the catheter's resistance to pulling force. Using an ex vivo porcine limb model, we compared the conventional CTN design with the CON design with respect to the ability to resist leakage at the catheter insertion site under high injection pressure and the force required to withdraw the catheter from tissue. One CON assembly (MultiSet, Pajunk) and three CTN assemblies (Contiplex, B.Braun; StimuCath, Arrow; Stimulong Sono, Pajunk) were studied. Ten porcine hind limbs were used to test leakage and another ten were used to measure withdrawal force. Catheters were placed at angles of 15° and 30° at depths of 3 cm and 5 cm. Leakage was assessed visually at the insertion site, and pressure was measured at the moment leakage occurred. Withdrawal force was measured by pulling the catheter from the tissue. No evidence of leakage was detected at the CON catheter insertion site at the highest pressure applied (1,000 mmHg) (n = 40). The CON assembly withstood significantly higher injection pressure than the CTN catheters without causing leaks at the catheter insertion site [CON, mean (standard deviation) > 1,000 (0) mmHg; B.Braun, 596 (92) mmHg; Pajunk Stimulong, 615 (107) mmHg; and Arrow, 422 (104) mmHg; P < 0.001 CON vs CTN]. The force required to withdraw the catheter from the porcine limb was greater with CON catheters [3.8 (0.8) N] than with any of the CTN catheters [range, 0.4 (0.2) - 0.8 (0.2) N], depending on depth, angle, and manufacturer (P < 0.001 CON vs CTN). In the porcine leg model, CON catheterization provides greater resistance to leakage under high injection pressure and greater holding force in tissue than traditional CTN catheters.

  15. A Case of Sheathless Transradial Coronary Intervention for Complex Coronary Lesions with a Standard Guiding Catheter

    Science.gov (United States)

    Choi, Jaehuk; Suh, Jon; Seo, Hye-Sun; Cho, Yoon Haeng

    2013-01-01

    One of the major limitations of transradial coronary intervention is the inability to use large guiding system, which leads to the development of dedicated sheathless guide catheter system. However, these devices are not available in the Republic of Korea. We present a case in which conventional guiding catheter was used for sheathless transradial coronary intervention in the treatment of complex coronary anatomy. PMID:23755083

  16. Analysis and compensation for the effect of the catheter position on image intensities in intravascular optical coherence tomography

    DEFF Research Database (Denmark)

    Liu, Shengnan; Eggermont, Jeroen; Wolterbeek, Ron

    2016-01-01

    Intravascular optical coherence tomography (IVOCT) is an imaging technique that is used to analyze the underlying cause of cardiovascular disease. Because a catheter is used during imaging, the intensities can be affected by the catheter position. This work aims to analyze the effect...... of the catheter position on IVOCT image intensities and to propose a compensation method to minimize this effect in order to improve the visualization and the automatic analysis of IVOCT images. The effect of catheter position is modeled with respect to the distance between the catheter and the arterial wall...

  17. Malfunctioning and infected tunneled infusion catheters: over-the-wire catheter exchange versus catheter removal and replacement.

    Science.gov (United States)

    Guttmann, David M; Trerotola, Scott O; Clark, Timothy W; Dagli, Mandeep; Shlansky-Goldberg, Richard D; Itkin, Maxim; Soulen, Michael C; Mondschein, Jeffrey I; Stavropoulos, S William

    2011-05-01

    To compare the safety and effectiveness of over-the-wire catheter exchange (catheter-exchange) with catheter removal and replacement (removal-replacement) at a new site for infected or malfunctioning tunneled infusion catheters. Using a quality assurance database, 61 patients with tunneled infusion catheters placed during the period July 2001 to June 2009 were included in this study. Patients receiving hemodialysis catheters were excluded. Catheter-exchange was performed in 25 patients, and same-day removal-replacement was performed in 36 patients. Data collected included demographic information, indication for initial catheter placement and replacement, dwell time for the new catheter, and ultimate fate of the new device. Statistical comparisons between the two cohorts were analyzed using the Kaplan-Meier technique and Fisher exact test. Catheters exchanged over the wire remained functional without infection for a median of 102 days (range, 2-570 days), whereas catheters removed and replaced were functional for a median 238 days (range, 1-292 days, P = .12). After catheter replacement, there were 11 instances of subsequent infection in the catheter-exchange group and 7 instances in the removal-replacement cohort, accounting for infection rates of 4.4 and 2.3 per 1,000 catheter days (P = .049). Patients in the catheter-exchange group had 3.2 greater odds of infection compared with patients in the removal-replacement group. Five malfunction events occurred in each group, accounting for 2.0 and 1.7 malfunctions per 1,000 catheter days in the catheter-exchange and removal-replacement groups (P = .73). Catheter-exchange of tunneled infusion catheters results in a higher infection rate compared with removal-replacement at a new site. The rate of catheter malfunction is not significantly different between the two groups. Catheter-exchange is an alternative for patients with tunneled infusion catheters who have limited venous access, but this technique should not be

  18. Virtual Breakthrough Series, Part 1: Preventing Catheter-Associated Urinary Tract Infection and Hospital-Acquired Pressure Ulcers in the Veterans Health Administration.

    Science.gov (United States)

    Zubkoff, Lisa; Neily, Julia; King, Beth J; Dellefield, Mary Ellen; Krein, Sarah; Young-Xu, Yinong; Boar, Shoshana; Mills, Peter D

    2016-11-01

    In 2014 the Veterans Health Administration (VHA) of the Department of Veterans Affairs (VA) implemented a Virtual Breakthrough Series (VBTS) collaborative to help VHA facilities prevent hospital-acquired conditions: catheter-associated urinary tract infection (CAUTI) and hospital-acquired pressure ulcers (HAPUs). During the prework phase, participating facilities assembled a multidisciplinary team, assessed their current system for CAUTI or HAPU prevention, and examined baseline data to set improvement aims. The action phase consisted of educational conference calls, coaching, and monthly team reports. Learning was conducted via phone, web-based options, and e-mail. The CAUTI bundle focused on four key principles: (1) avoidance of indwelling urinary catheters, (2) proper insertion technique, (3) proper catheter maintenance, and (4) timely removal of the indwelling catheter. The HAPU bundle focused on assessment and inspection, pressure-relieving surfaces, turning and repositioning, incontinence management, and nutrition/hydration assessment and intervention. For the 18 participating units, the mean aggregated CAUTI rate decreased from 2.37 during the prework phase to 1.06 per 1,000 catheter-days during the action (implementation) phase (p model for implementing a virtual model for improvement. Copyright 2016 The Joint Commission.

  19. Information Systems Efficiency Model

    Directory of Open Access Journals (Sweden)

    Milos Koch

    2017-07-01

    Full Text Available This contribution discusses the basic concept of creating a new model for the efficiency and effectiveness assessment of company information systems. The present trends in this field are taken into account, and the attributes are retained of measuring the optimal solutions for a company’s ICT (the implementation, functionality, service, innovations, safety, relationships, costs, etc.. The proposal of a new model of assessment comes from our experience with formerly implemented and employed methods, methods which we have modified in time and adapted to companies’ needs but also to the necessaries of our research that has been done through the ZEFIS portal. The most noteworthy of them is the HOS method that we have discussed in a number of forums. Its main feature is the fact that it respects the complexity of an information system in correlation with the balanced state of its individual parts.

  20. Translumbar aortography by catheter technique

    International Nuclear Information System (INIS)

    Hagen, B.; Honemeyer, U.; Meier-Duis, H.

    1982-01-01

    400 examinations performed during the last three years by TLA (only catheter technique) were subjected to critical analysis and studied particularly in respect to the rate of complications. We observed 13 complications (3.25%) of moderate severity, including 3 large hematomas (documented by CT), 3 paravasations and 7 dissections, but no fatal complication. Two (0.5%) of these complications had clinical evidence. The advantages of the catheter technique of TLA are described. Injections through rigid metal cannula should be avoided because of the high incidence of complications (mainly the increased risk of dissection). Downstream injection resulted in excellent visualization of peripheral occluding vascular disease. Upstream injection should be preferred to demonstrate the major abdominal arteries as well as supraceliac collateral circulation in the case of high Leriche syndrome. The low or intermediate puncture of the aorta is preferable to facilitate caudad direction of the catheter and to diminish the risk of damaging other vessels or puncturing an organ. (orig.) [de

  1. Catheter Migration After Implantationan Intrathecal Baclofen Infusion Pump for Severe Spasticity: A Case Report

    Directory of Open Access Journals (Sweden)

    Tung-Chou Li

    2008-09-01

    Full Text Available We report a case of intrathecal baclofen infusion pump implantation complicated by migration of the catheter tip. A 55-year-old man required an intrathecal baclofen infusion for severe spasticity 4 years after a cervical spinal cord injury with incomplete tetraparesis. Twelve months after initial implantation of the device, the patient began to experience a recurrence of trunk tightness and spasticity. Subsequent X-ray and computed tomography evaluations of the catheter system revealed pooling of contrast medium outside of the intrathecal distribution in the lumbar subcutaneous region of the back and therefore migration of the pump catheter tip. At surgical revision, emphasis was placed on minimizing the length of catheter outside of the spine and securing the catheter in the supraspinous fascia with a right-angled anchor. The distance between the anchors and the entry point of the catheter into the supraspinous fascia was also reduced to prevent slipping when the patient bends forward. After surgery, the patient's spasticity improved and, 1 year later, he has experienced no further complications during follow-up, requiring an average baclofen dose of 150 mg/day. Here, we describe several surgical methods intended to secure the intrathecal catheter and prevent catheter migration. Other complications related to catheter failure are also highlighted.

  2. Thoracic Nerve Root Entrapment by Intrathecal Catheter Coiling: Case Report and Review of the Literature.

    Science.gov (United States)

    Han, Jing L; Loriaux, Daniel B; Tybout, Caroline; Kinon, Merritt D; Rahimpour, Shervin; Runyon, Scott L; Hopkins, Thomas J; Boortz-Marx, Richard L; Lad, Shivanand P

    2016-03-01

    Intrathecal catheter placement has long-term therapeutic benefits in the management of chronic, intractable pain. Despite the diverse clinical applicability and rising prevalence of implantable drug delivery systems in pain medicine, the spectrum of complications associated with intrathecal catheterization remains largely understudied and underreported in the literature. To report a case of thoracic nerve root entrapment resulting from intrathecal catheter migration. Case report. Inpatient hospital service. A 60-year-old man status post implanted intrathecal (IT) catheter for intractable low back pain secondary to failed back surgery syndrome returned to the operating room for removal of IT pump trial catheter after experiencing relapse of preoperative pain and pump occlusion. Initial attempt at ambulatory removal of the catheter was aborted after the patient reported acute onset of lower extremity radiculopathic pain during the extraction. Noncontrast computed tomography (CT) subsequently revealed that the catheter had ascended and coiled around the T10 nerve root. The patient was taken back to the operating room for removal of the catheter under fluoroscopic guidance, with possible laminectomy for direct visualization. Removal was ultimately achieved with slow continuous tension, with complete resolution of the patient's new radicular symptoms. This report describes a single case report. This case demonstrates that any existing loops in the intrathecal catheter during initial implantation should be immediately re-addressed, as they can precipitate nerve root entrapment and irritation. Reduction of the loop or extrication of the catheter should be attempted under continuous fluoroscopic guidance to prevent further neurosurgical morbidity.

  3. A 4-DOF Robot for Positioning Ultrasound Imaging Catheters.

    Science.gov (United States)

    Loschak, Paul M; Degirmenci, Alperen; Tenzer, Yaroslav; Howe, Robert D

    2015-08-01

    In this paper we present the design, fabrication, and testing of a robot for automatically positioning ultrasound imaging catheters. Our system will point ultrasound (US) catheters to provide real-time imaging of anatomical structures and working instruments during minimally invasive surgeries. Manually navigating US catheters is difficult and requires extensive training in order to aim the US imager at desired targets. Therefore, a four DOF robotic system was developed to automatically navigate US imaging catheters for enhanced imaging. A rotational transmission enables three DOF for pitch, yaw, and roll of the imager. This transmission is translated by the fourth DOF. An accuracy analysis was conducted to calculate the maximum allowable joint motion error. Rotational joints must be accurate to within 1.5° and the translational joint must be accurate within 1.4 mm. Motion tests were then conducted to validate the accuracy of the robot. The average resulting errors in positioning of the rotational joints were measured to be 0.28°-0.38° with average measured backlash error 0.44°. Average translational positioning and backlash errors were measured to be significantly lower than the reported accuracy of the position sensor. The resulting joint motion errors were well within the required specifications for accurate robot motion. Such effective navigation of US imaging catheters will enable better visualization in various procedures ranging from cardiac arrhythmia treatment to tumor removal in urological cases.

  4. First-in-human experience using the Volcano VIBE-RX vascular imaging balloon catheter system (Volcano IVUS-guided Balloon Evaluation - New Zealand: VIBE-NZ Study).

    Science.gov (United States)

    Watson, Timothy; El-Jack, Seifeddin; Stewart, James T; Ormiston, John

    2013-09-01

    Intravascular ultrasound (IVUS) is a proven and safe imaging modality used to guide percutaneous coronary intervention (PCI). The Volcano VIBE™ RX Vascular Imaging Balloon Catheter is a novel rapid exchange, 0.014" wire-compatible multi-lumen conventional balloon catheter modified with the addition of an IVUS transducer proximal to the balloon, delivered via a standard 6 Fr sheath. We sought to evaluate the safety, balloon performance, and image quality of the VIBE™ RX in patients scheduled for coronary intervention. Patients aged >21 and <85 years with single or multivessel coronary disease scheduled for PCI due to coronary ischaemic symptoms were included. Those with angiographic features that precluded the safe or informative use of the device were excluded. Twenty-nine patients having angiography because of ischaemic symptoms underwent 44 VIBE RX imaging runs, with balloon dilation in 20. Successful device deployment was achieved in all but one patient. All images were adequate and reproducible. One patient had a non-ST-elevation MI felt to be due to the complexity of the procedure rather than directly related to the VIBE™ RX. The study demonstrated the safety and effectiveness of the VIBE™ RX for its intended purpose with minimal failure rate and no directly related complications.

  5. 3D Catheter Shape Determination for Endovascular Navigation Using a Two-Step Particle Filter and Ultrasound Scanning.

    Science.gov (United States)

    Chen, Fang; Liu, Jia; Liao, Hongen

    2017-03-01

    In endovascular catheter interventions, the determination of the three-dimensional (3D) catheter shape can increase navigation information and help reduce trauma. This study describes a shape determination method for a flexible interventional catheter using ultrasound scanning and a two-step particle filter without X-ray fluoroscopy. First, we propose a multi-feature, multi-template particle filter algorithm for accurate catheter tracking from ultrasound images. Second, we model the mechanical behavior of the catheter and apply a particle filter shape optimization algorithm to refine the results from the first step. Finally, the acquired catheter's 3D shapes are displayed together with the preoperative 3D images of the cardiac structures to provide intuitive endovascular navigation. We validated our method using ultrasound scanning of the straight and curved catheters in a water tank, and the shape determination errors were 1.44 ± 0.38 mm and 1.95 ± 0.46 mm, respectively. Further, endovascular catheter shape determination was validated in a catheter intervention experiment with a heart phantom. The error of the acquired endovascular catheter shape was 2.23 ± 0.87 mm. These results demonstrate that our two-step method is both accurate and effective. Using ultrasound scanning for shape determination of a flexible catheter will be helpful in endovascular interventions, reducing exposure to radiation and providing rich navigation information.

  6. Central venous catheter associated thrombosis of major veins: thrombolytic treatment with recombinant tissue plasminogen activator

    NARCIS (Netherlands)

    Rodenhuis, S.; van't Hek, L. G.; Vlasveld, L. T.; Kröger, R.; Dubbelman, R.; van Tol, R. G.

    1993-01-01

    Major thromboses can occur in the venous system in association with central venous catheters. This usually necessitates removal of the catheter. The effectiveness of low dose recombinant tissue type plasminogen activator (rt-PA) in combination with heparin was assessed in patients with central

  7. Transhepatic venous catheters for hemodialysis

    Directory of Open Access Journals (Sweden)

    Mohamed El Gharib

    2014-06-01

    Conclusion: Based on our findings, transhepatic hemodialysis catheters have proven to achieve good long-term functionality. A high level of maintenance is required to preserve patency, although this approach provides remarkably durable access for patients who have otherwise exhausted access options.

  8. Hemodialysis Catheter Heat Transfer for Biofilm Prevention and Treatment.

    Science.gov (United States)

    Richardson, Ian P; Sturtevant, Rachael; Heung, Michael; Solomon, Michael J; Younger, John G; VanEpps, J Scott

    2016-01-01

    Central line-associated bloodstream infections (CLABSIs) are not easily treated, and many catheters (e.g., hemodialysis catheters) are not easily replaced. Biofilms (the source of infection) on catheter surfaces are notoriously difficult to eradicate. We have recently demonstrated that modest elevations of temperature lead to increased staphylococcal susceptibility to vancomycin and significantly soften the biofilm matrix. In this study, using a combination of microbiological, computational, and experimental studies, we demonstrate the efficacy, feasibility, and safety of using heat as an adjuvant treatment for infected hemodialysis catheters. Specifically, we show that treating with heat in the presence of antibiotics led to additive killing of Staphylococcus epidermidis with similar trends seen for Staphylococcus aureus and Klebsiella pneumoniae. The magnitude of temperature elevation required is relatively modest (45-50°C) and similar to that used as an adjuvant to traditional cancer therapy. Using a custom-designed benchtop model of a hemodialysis catheter, positioned with tip in the human vena cava as well as computational fluid dynamic simulations, we demonstrate that these temperature elevations are likely achievable in situ with minimal increased in overall blood temperature.

  9. Button self-retaining drainage catheter

    International Nuclear Information System (INIS)

    Caridi, James G.; Hawkins, Irvin F.; Akins, E. William; Young, Ronald S.

    1997-01-01

    To help improve patient acceptance of long-term internal/external catheter access to the biliary tract in those with benign biliary obstruction, a simple design allows the catheter end to remain flush with the skin. It consists of a clothes button affixed to the drainage catheter with a wood screw after the catheter has been cut off at the skin exit. This button/screw device has been used successfully in 22 patients over the last 10 years; catheter exchanges were easily accomplished

  10. Totally implantable catheter embolism: two related cases

    Directory of Open Access Journals (Sweden)

    Rodrigo Chaves Ribeiro

    Full Text Available CONTEXT AND OBJECTIVE: Long-term totally implantable catheters (e.g. Port-a-Cath® are frequently used for long-term venous access in children with cancer. The use of this type of catheter is associated with complications such as infection, extrusion, extravasation and thrombosis. Embolism of catheter fragments is a rare complication, but has potential for morbidity. The aim here was to report on two cases in which embolism of fragments of a long-term totally implantable catheter occurred. DESIGN AND SETTING: Case series study at Hospital do Servidor Público Estadual, São Paulo. METHODS: Retrospective review of catheter embolism in oncological pediatric patients with long-term totally implantable catheters. RESULTS: The first patient was a 3-year-old girl diagnosed with stage IV Wilms' tumor. Treatment was started with the introduction of a totally implantable catheter through the subclavian vein. At the time of removal, it was realized that the catheter had fractured inside the heart. An endovascular procedure was necessary to remove the fragment. The second case was a boy diagnosed with stage II Wilms' tumor at the age of two years. At the time of removal, it was noticed that the catheter had disconnected from the reservoir and an endovascular procedure was also necessary to remove the embolized catheter. CONCLUSION: Embolism of fragments of totally implantable catheters is a rare complication that needs to be recognized even in asymptomatic patients.

  11. Medically Attended Catheter Complications Are Common in Patients With Outpatient Central Venous Catheters.

    Science.gov (United States)

    Spires, Steven S; Rebeiro, Peter F; Miller, Mickie; Koss, Katie; Wright, Patty W; Talbot, Thomas R

    2018-04-01

    OBJECTIVE Outpatient central venous catheters (CVCs) are being used more frequently; however, data describing mechanical complications and central-line-associated bloodstream infections (CLABSI) in the outpatient setting are limited. We performed a retrospective observational cohort study to understand the burden of these complications to elucidate their impact on the healthcare system. METHODS Data were retrospectively collected on patients discharged from Vanderbilt University Medical Center with a CVC in place and admitted into the care of Vanderbilt Home Care Services. Risk factors for medically attended catheter-associated complications (CACs) and outpatient CLABSIs were analyzed. RESULTS A CAC developed in 143 patients (21.9%), for a total of 165 discrete CAC events. Among these, 76 (46%) required at least 1 visit to the emergency department or an inpatient admission, while the remaining 89 (54%) required an outpatient clinic visit. The risk for developing a CAC was significantly increased in female patients, patients with a CVC with >1 lumen, and patients receiving total parenteral nutrition. The absolute number of CLABSIs identified in the study population was small at 16, or 2.4% of the total cohort. CONCLUSIONS Medically attended catheter complications were common among outpatients discharged with a CVC, and reduction of these events should be the focus of outpatient quality improvement programs. Infect Control Hosp Epidemiol 2018;39:439-444.

  12. A fully automatic device for compensating for artifacts in conventional catheter-manometer pressure recordings.

    Science.gov (United States)

    Brower, R W; Spaans, W; Rewiersma, P A; Meester, G T

    1975-08-01

    A device is described which detects the resonant artifacts in clinical cathetermanometer systems and automatically sets a notch filter so as to provide some measure of compensation. The equalised response characteristic does visibly improve transient response by removing resonant artifacts due to the uneven transfer function characteristic in these systems. Artifacts due to knocking of the catheter by the heart, external vibrations induced in the manometer, its mechanical support, or the catheter are reduced, but not eliminated. Nevertheless, the system described here has provided a solution to an important class of artifacts in conventional fluid filled catheter-manometer pressure recordings.

  13. A National Implementation Project to Prevent Catheter-Associated Urinary Tract Infection in Nursing Home Residents.

    Science.gov (United States)

    Mody, Lona; Greene, M Todd; Meddings, Jennifer; Krein, Sarah L; McNamara, Sara E; Trautner, Barbara W; Ratz, David; Stone, Nimalie D; Min, Lillian; Schweon, Steven J; Rolle, Andrew J; Olmsted, Russell N; Burwen, Dale R; Battles, James; Edson, Barbara; Saint, Sanjay

    2017-08-01

    Catheter-associated urinary tract infection (UTI) in nursing home residents is a common cause of sepsis, hospital admission, and antimicrobial use leading to colonization with multidrug-resistant organisms. To develop, implement, and evaluate an intervention to reduce catheter-associated UTI. A large-scale prospective implementation project was conducted in community-based nursing homes participating in the Agency for Healthcare Research and Quality Safety Program for Long-Term Care. Nursing homes across 48 states, Washington DC, and Puerto Rico participated. Implementation of the project was conducted between March 1, 2014, and August 31, 2016. The project was implemented over 12-month cohorts and included a technical bundle: catheter removal, aseptic insertion, using regular assessments, training for catheter care, and incontinence care planning, as well as a socioadaptive bundle emphasizing leadership, resident and family engagement, and effective communication. Urinary catheter use and catheter-associated UTI rates using National Healthcare Safety Network definitions were collected. Facility-level urine culture order rates were also obtained. Random-effects negative binomial regression models were used to examine changes in catheter-associated UTI, catheter utilization, and urine cultures and adjusted for covariates including ownership, bed size, provision of subacute care, 5-star rating, presence of an infection control committee, and an infection preventionist. In 4 cohorts over 30 months, 568 community-based nursing homes were recruited; 404 met inclusion criteria for analysis. The unadjusted catheter-associated UTI rates decreased from 6.78 to 2.63 infections per 1000 catheter-days. With use of the regression model and adjustment for facility characteristics, the rates decreased from 6.42 to 3.33 (incidence rate ratio [IRR], 0.46; 95% CI, 0.36-0.58; P < .001). Catheter utilization was 4.5% at baseline and 4.9% at the end of the project. Catheter

  14. Comparison of hospital length of stay, costs, and readmissions of alteplase versus catheter replacement among patients with occluded central venous catheters.

    Science.gov (United States)

    Ernst, Frank R; Chen, Er; Lipkin, Craig; Tayama, Darren; Amin, Alpesh N

    2014-08-01

    Central venous catheter (CVC) occlusion is common, affecting 30% of all CVCs. To compare length of stay (LOS), costs, and readmissions associated with the use of alteplase to clear catheter blockage to outcomes associated with catheter replacement. Retrospective observational study utilizing a large hospital database. Hospitalized patients treated for catheter occlusion from January 2006 to December 2011. Univariate analyses of patient characteristics and treatment patterns and multivariable regression analyses of postocclusion hospital costs, LOS, and 30- and 90-day readmissions were conducted. We included 34,579 patients treated for a CVC occlusion by replacement (N=1028) or by alteplase (2 mg) administration (N=33,551). Patients receiving alteplase were somewhat younger than those having catheter replacement (60 ± 19 vs 62 ± 20 years old, P=0.0002). After adjusting for patient and hospital factors via regression modeling, average daily postocclusion costs were $317 lower for alteplase recipients than for catheter replacement patients (95% confidence interval [CI]: 238.22-392.24; P0.05). Odds of readmission were not significantly different at 30 or 90 days. Among patients treated for an occluded CVC, alteplase-treated patients had lower daily and total postocclusion costs than patients receiving catheter replacement. Cost differences were mainly driven by lower operating room/surgery, radiology, and supplier costs. Published 2014. The Authors Journal of Hospital Medicine published by Wiley Periodicals, Inc. on behalf of Society of Hospital Medicine.

  15. Transradial percutaneous coronary interventions using sheathless guiding catheters: a multicenter registry.

    Science.gov (United States)

    Sciahbasi, Alessandro; Mancone, Massimo; Cortese, Bernardo; Pendenza, Gianluca; Romagnoli, Enrico; Fischetti, Dionigi; Tomassini, Francesco; Sardella, Gennaro; Lioy, Ernesto

    2011-10-01

    Transradial approach (TRA) for percutaneous coronary interventions (PCIs) is a common alternative to transfemoral approach associated with lower complications. However, a limitation of TRA is the use of large caliber guiding catheters due to the small size of the radial artery. The sheathless guiding catheter system that is in diameter 1-2 French (Fr) smaller than the corresponding introducer sheath may overcome these difficulties. From January 2010 through December 2010 in 5 Italian high-volume hospitals, 213 consecutive patients who underwent TRA-PCIs using the sheathless Eaucath guiding catheter system because of small radial artery caliber (Group 1) or undergoing bifurcation PCIs (Group 2) were enrolled in this registry. In patients of Group 1 (n = 79), a 6.5-Fr sheathless guiding catheter was employed, whereas in patients of Group 2 (n = 134) a 7.5 Fr was used. Among the 213 patients enrolled, 270 vessels were treated for 316 lesions. No procedures required conversion to a conventional guiding catheter system. There were significantly more female patients in Group 1, and they were, older, shorter, and thinner than patients in Group 2. No cases of major vascular complications were observed in either groups. During procedures, adjunctive devices employed included intravascular ultrasound, thrombectomy catheters, and distal protection systems. The use of the sheathless guiding catheter system is feasible for TRA-PCIs in case of small radial artery caliber or intended coronary bifurcation intervention. ©2011, Wiley Periodicals, Inc.

  16. Hydronephrosis Predicts Successful Catheter Removal after Painful Urinary Retention - Preliminary Results of a Prospective Single Center Study.

    Science.gov (United States)

    Heidegger, Isabel; Fritz, Josef; Steiner, Hannes; Bektic, Jasmin; Pichler, Renate

    2016-01-01

    The study aims to identify candidates who can be managed conservatively after the first episode of spontaneous painful acute urinary retention (AUR). A total of 20 patients with primary spontaneous painful AUR were prospectively included in the study. Twenty-four hours after AUR, the catheter was removed. When residual urinary volume was <100 ml, patients were referred without catheter, when residual urinary volume was ≥100 ml, the catheter was replaced and removed again at day 4, 7 or 10 after AUR, respectively. Receiver operating characteristic curves, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to assess predictors for successful catheter removal. Thirteen out of 20 (65%) patients had a successful catheter removal until day 10 after AUR. Among them 12 of 13 (93.2%) had a successful catheter removal until day 4 of AUR. Hydronephrosis urinary volume and Qmax at the time of AUR were significant numeric predictors for failure of successful catheter removal. In addition, we calculated a prediction model combing age + prostate volume + urinary volume + Qmax that highly predicts successful catheter removal (sensitivity 100%, specificity 69%, PPV 64%, NPV 100%). We found for the first time a significant association between hydronephrosis and successful catheter removal. Successful catheter removal until day 4 after AUR can safely be managed without immediate transurethral resection of the prostate. © 2015 S. Karger AG, Basel.

  17. A randomized controlled trial of coiled versus straight swan-neck Tenckhoff catheters in peritoneal dialysis patients.

    Science.gov (United States)

    Johnson, David W; Wong, Jennifer; Wiggins, Kathryn J; Kirwan, Robyn; Griffin, Anthony; Preston, John; Wall, Daryl; Campbell, Scott B; Isbel, Nicole M; Mudge, David W; Hawley, Carmel M; Nicol, David L

    2006-11-01

    Current clinical practice guidelines recommend that no particular type of peritoneal dialysis (PD) catheter has been proved superior to another. However, a recent Cochrane review recommended the need for a large, well-designed, randomized, controlled trial of straight versus coiled PD catheters because of the paucity and suboptimal quality of previously performed trials. A randomized controlled trial was undertaken at 2 metropolitan teaching hospitals comparing the effects of straight versus coiled PD catheters on time to catheter malposition (primary outcome), catheter-associated infection, technique failure, and all-cause mortality. One hundred thirty-two PD patients were enrolled and randomly assigned to insertion of a coiled (n = 62) or straight catheter (n = 70). There was no significant difference in time to laparoscopic reposition between the 2 cohorts (log-rank score, 0.41; P = 0.52). However, median technique survival was significantly worse for coiled catheters (1.5 years; 95% confidence interval [CI], 1.2 to 1.8) compared with straight catheters (2.1 years; 95% CI, 1.8 to 2.5; P < 0.05), primarily because of increased risk for inadequate dialytic clearance with the former. On univariate Cox proportional hazards model analysis, insertion of a coiled PD catheter was associated significantly with a greater risk for technique failure (unadjusted hazard ratio, 1.86; 95% CI, 1.03 to 3.36). No difference was observed between the 2 groups with respect to catheter-associated infections or overall patient survival. Coiled catheters do not influence the risk for drainage failure caused by catheter malposition compared with straight catheters, but are associated with significantly increased risk for PD technique failure, primarily because of inadequate dialytic clearance.

  18. Dynamic response of liquid-filled catheter systems for measurement of blood pressure: precision of measurements and reliability of the Pressure Recording Analytical Method with different disposable systems.

    Science.gov (United States)

    Romagnoli, Stefano; Romano, Salvatore Mario; Bevilacqua, Sergio; Lazzeri, Chiara; Gensini, Gian Franco; Pratesi, Carlo; Quattrone, Diego; Dini, Daniele; De Gaudio, Angelo Raffaele

    2011-08-01

    We aimed to compare the effects of a blood pressure transducer system specifically manufactured to limit underdamping artifacts with those of a standard system on hemodynamic parameter estimation and accuracy. Forty-three consecutive patients undergoing vascular surgery at the University of Florence, Italy, were included. Arterial blood pressure signal was simultaneously registered with 2 MostCare monitors, connected to the artery either by a standard transducer or a specific transducer manufactured to avoid underdamping artifacts (Resonance Over-Shoot Eliminator [R.O.S.E.]; Becton Dickinson, Becton Drive, NJ). Patients were divided into 2 groups: absence (C group) or presence (R group) of underdamping/resonance artifacts of blood pressure signal. Systolic blood pressure, cardiac index, maximal pressure/time ratio (dP/dt(MAX)), and cardiac cycle efficiency were recorded every 30 seconds for 30 minutes. A total of 2675 measurements were performed with 34.9% incidence of underdamping/resonance artifacts. All hemodynamic parameters showed clinically acceptable differences in the C group; in contrast, the results differed greatly in the R group between standard and R.O.S.E. transducer (systolic blood pressure bias, 16.7 mm Hg; cardiac index bias, 0.24 L min(-1) m(-2); dP/dt(MAX) bias, 0.92 mm Hg/ms; cardiac cycle efficiency bias, 0.018 units). Underdamping/resonance artifacts frequently affect blood pressure measurement in operating rooms and intensive care units and cause severe overestimation of systolic blood pressure and incorrect estimation of hemodynamic parameters when the pulse contour method is used. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Modeling and estimating system availability

    International Nuclear Information System (INIS)

    Gaver, D.P.; Chu, B.B.

    1976-11-01

    Mathematical models to infer the availability of various types of more or less complicated systems are described. The analyses presented are probabilistic in nature and consist of three parts: a presentation of various analytic models for availability; a means of deriving approximate probability limits on system availability; and a means of statistical inference of system availability from sparse data, using a jackknife procedure. Various low-order redundant systems are used as examples, but extension to more complex systems is not difficult

  20. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yingliang; Housden, R. James; Razavi, Reza; Rhode, Kawal S. [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH (United Kingdom); Gogin, Nicolas; Cathier, Pascal [Medisys Research Group, Philips Healthcare, Paris 92156 (France); Gijsbers, Geert [Interventional X-ray, Philips Healthcare, Best 5680 DA (Netherlands); Cooklin, Michael; O' Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo [Department of Cardiology, Guys and St. Thomas' Hospitals NHS Foundation Trust, London SE1 7EH (United Kingdom)

    2013-07-15

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 {+-} 0.29, 0.92 {+-} 0.61, and 0.63 {+-} 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 {+-} 0.28, 0.64 {+-} 0.37, and 0.53 {+-} 0.38 mm and success rates increased to 100%, 99

  1. Malposition of catheters during voiding cystourethrography

    Energy Technology Data Exchange (ETDEWEB)

    Rathaus, V.; Konen, O.; Shapiro, M. [Dept. of Diagnostic Imaging Sapir Medical Center, Kfar-Saba and Sackler Medical School, Tel Aviv University (Israel); Grunebaum, M. [Veteran Pediatric Radiologist, Kfar Saba (Israel)

    2001-04-01

    The aim of this study was to report catheter malposition during voiding cystourethrography. Eight hundred forty-three voiding cystourethrography (265 males and 578 females, aged 1 week to 12 years, mean age 2 years) were performed during a period of 4 years. The conventional standard procedure was applied. In 3 cases with passed history of urinary tract infection the catheter entered directly into the ureter. In all these cases the uretero-vesical reflux was present on the same side where the catheter entered. It appears that insertion of a catheter into the ureter is possible only in the presence of an anomaly or pathology at the vesicoureteric junction. (orig.)

  2. Co-release of dicloxacillin and thioridazine from catheter material containing an interpenetrating polymer network for inhibiting device-associated Staphylococcus aureus infection

    DEFF Research Database (Denmark)

    Stenger, Michael; Klein, Kasper; Grønnemose, Rasmus B

    2016-01-01

    Approximately half of all nosocomial bloodstream infections are caused by bacterial colonization of vascular catheters. Attempts have been made to improve devices using anti-adhesive or antimicrobial coatings; however, it is often difficult to bind coatings stably to catheter materials, and the low...... to an enhanced loading capacity of DCX when co-loaded with TDZ. Lastly, the IPN catheters were tested in a novel porcine model of central venous catheter-related infection, in which drug-loaded IPN catheters were found to significantly decrease the frequency of infection....

  3. Modelling of reverberation enhancement systems

    OpenAIRE

    ROUCH , Jeremy; Schmich , Isabelle; Galland , Marie-Annick

    2012-01-01

    International audience; Electroacoustic enhancement systems are increasingly specified by acoustic consultants to address the requests for a multi-purpose use of performance halls. However, there is still a lack of simple models to predict the effect induced by these systems on the acoustic field. Two models are introduced to establish the impulse responses of a room equipped with a reverberation enhancement system. These models are based on passive impulse responses according to the modified...

  4. MODELLING OF MATERIAL FLOW SYSTEMS

    OpenAIRE

    PÉTER TELEK

    2012-01-01

    Material flow systems are in generally very complex processes. During design, building and operation of complex systems there are many different problems. If these complex processes can be described in a simple model, the tasks will be clearer, better adaptable and easier solvable. As the material flow systems are very different, so using models is a very important aid to create uniform methods and solutions. This paper shows the details of the application possibilities of modelling in the ma...

  5. Dynamic Modeling of ALS Systems

    Science.gov (United States)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  6. Modeling soft interface dominated systems

    NARCIS (Netherlands)

    Lamorgese, A.; Mauri, R.; Sagis, L.M.C.

    2017-01-01

    The two main continuum frameworks used for modeling the dynamics of soft multiphase systems are the Gibbs dividing surface model, and the diffuse interface model. In the former the interface is modeled as a two dimensional surface, and excess properties such as a surface density, or surface energy

  7. Validation of systems biology models

    NARCIS (Netherlands)

    Hasdemir, D.

    2015-01-01

    The paradigm shift from qualitative to quantitative analysis of biological systems brought a substantial number of modeling approaches to the stage of molecular biology research. These include but certainly are not limited to nonlinear kinetic models, static network models and models obtained by the

  8. From Numeric Models to Granular System Modeling

    Directory of Open Access Journals (Sweden)

    Witold Pedrycz

    2015-03-01

    To make this study self-contained, we briefly recall the key concepts of granular computing and demonstrate how this conceptual framework and its algorithmic fundamentals give rise to granular models. We discuss several representative formal setups used in describing and processing information granules including fuzzy sets, rough sets, and interval calculus. Key architectures of models dwell upon relationships among information granules. We demonstrate how information granularity and its optimization can be regarded as an important design asset to be exploited in system modeling and giving rise to granular models. With this regard, an important category of rule-based models along with their granular enrichments is studied in detail.

  9. Coastal Modeling System Advanced Topics

    Science.gov (United States)

    2012-06-18

    22 June 2012 - Day 5  Debugging and Problem solving  Model Calibration  Post-processing Coastal and Hydraulics Laboratory Focus of...Efficiently: • The setup process is fast and without wasted time or effort 3 Coastal and Hydraulics Laboratory 4 Coastal Modeling System (CMS) What...is the CMS? Integrated wave, current, and morphology change model in the Surface- water Modeling System (SMS). Why CMS? Operational at 10

  10. Safeguards system effectiveness modeling

    International Nuclear Information System (INIS)

    Bennett, H.A.; Boozer, D.D.; Chapman, L.D.; Daniel, S.L.; Engi, D.; Hulme, B.L.; Varnado, G.B.

    1976-01-01

    A general methodology for the comparative evaluation of physical protection system effectiveness at nuclear facilities is presently under development. The approach is applicable to problems of sabotage or theft at fuel cycle facilities. The overall methodology and the primary analytic techniques used to assess system effectiveness are briefly outlined

  11. Safeguards system effectiveness modeling

    International Nuclear Information System (INIS)

    Bennett, H.A.; Boozer, D.D.; Chapman, L.D.; Daniel, S.L.; Engi, D.; Hulme, B.L.; Varnado, G.B.

    1976-01-01

    A general methodology for the comparative evaluation of physical protection system effectiveness at nuclear facilities is presently under development. The approach is applicable to problems of sabotage or theft at fuel cycle facilities. In this paper, the overall methodology and the primary analytic techniques used to assess system effectiveness are briefly outlined

  12. Progress of Labor in Women Induced with Misoprostol versus the Foley Catheter

    Science.gov (United States)

    TUULI, Methodius G.; KEEGAN, Mary B.; ODIBO, Anthony O.; ROEHL, Kimberly; MACONES, George A.; CAHILL, Alison G.

    2014-01-01

    Objective To estimate and compare the duration and progress of labor in women induced with misoprostol versus Foley catheter plus oxytocin. Study Design We performed a retrospective cohort study of labor progress among 617 consecutive term pregnancies induced with misoprostol (n=503) or Foley catheter plus oxytocin (n=114) who completed the first stage of labor. Labor duration and progress in the entire cohort, and stratified by parity, were compared in multivariable interval-censored regression models adjusting for maternal obesity and birth weight. Repeated-measures analysis with 9th degree polynomial modeling was used to construct average labor curves. Results Total duration of labor was not significantly different in women induced with misoprostol compared to the Foley catheter median (median duration from 1 to 10 cm: 12 versus 14.2 hours, p=0.19). Progress from 1 to 4 cm was more rapid with the Foley catheter (median: 3.4 versus 5.6 hours, pmisoprostol and at 6cm for the Foley catheter. Similar general patterns were noted for nulliparous and multiparous women, except for a shorter duration of labor with the Foley catheter among multiparous women. Conclusion Induction of labor with the Foley catheter is associated with more rapid initial cervical dilation, but transition to active labor occurs later compared to misoprostol. These differences should be considered in the management of induced labor. PMID:23659988

  13. Combined ultrasound and fluoroscopy guided port catheter implantation-High success and low complication rate

    International Nuclear Information System (INIS)

    Gebauer, Bernhard; El-Sheik, Michael; Vogt, Michael; Wagner, Hans-Joachim

    2009-01-01

    Purpose: To evaluate peri-procedural, early and late complications as well as patients' acceptance of combined ultrasound and fluoroscopy guided radiological port catheter implantation. Materials and methods: In a retrospective analysis, all consecutive radiological port catheter implantations (n = 299) between August 2002 and December 2004 were analyzed. All implantations were performed in an angio suite under analgosedation and antibiotic prophylaxis. Port insertion was guided by ultrasonographic puncture of the jugular (n = 298) or subclavian (n = 1) vein and fluoroscopic guidance of catheter placement. All data of the port implantation had been prospectively entered into a database for interventional radiological procedures. To assess long-term results, patients, relatives or primary physicians were interviewed by telephone; additional data were generated from the hospital information system. Patients and/or the relatives were asked about their satisfaction with the port implantion procedure and long-term results. Results: The technical success rate was 99% (298/299). There were no major complications according to the grading system of SIR. A total of 23 (0.33 per 1000 catheter days) complications (early (n = 4), late (n = 19)) were recorded in the follow-period of a total of 72,727 indwelling catheter days. Infectious complications accounted for 0.15, thrombotic for 0.07 and migration for 0.04 complications per 1000 catheter days. Most complications were successfully treated by interventional measures. Twelve port catheters had to be explanted due to complications, mainly because of infection (n = 9). Patients' and relatives' satisfaction with the port catheter system was very high, even if complications occurred. Conclusion: Combined ultrasound and fluoroscopy guided port catheter implantation is a very safe and reliable procedure with low peri-procedural, early and late complication rate. The intervention achieves very high acceptance by the patients and

  14. Comparison of the Effectiveness of Three Methods of Recanalization in a Model of the Middle Cerebral Artery: Thrombus Aspiration via a 4F Catheter, Thrombus Aspiration via the GP Thromboaspiration Device, and Mechanical Thrombectomy Using the Solitaire Thrombectomy Device

    Directory of Open Access Journals (Sweden)

    Christopher Tennuci

    2011-01-01

    Full Text Available Introduction. This paper compares different approaches to recanalization in a model of the middle cerebral artery (MCA. Methods. An occlusive thrombus (lamb's blood was introduced into the MCA of a model of the cerebral circulation perfused with Hartmann's solution (80 pulsations/min, mean pressure 90 mm Hg. Three methods of clot retrieval were tested: thrombus aspiration via a 4F catheter (n=26, thrombus aspiration via the GP thrombus aspiration device (GPTAD (n=30, and mechanical thrombectomy via the Solitaire Device (n=30. Results. Recanalization rate was similar for all 3 approaches (62%, 77%, and 85%. Time to recanalization was faster with aspiration devices (41 SD 42 s for 4F and 61 SD 21 s for GPTAD than with the Solitaire (197 SD 64 s P<.05 Kruksal-Wallis. Clot fragmentation was the same in the Solitaire (23% and the GPTAD (23%, but higher with the 4F (53%, P<.05. Conclusion. In this model, thrombus aspiration was faster than mechanical thrombectomy, and similarly effective at recanalization. These results should be confirmed in vivo.

  15. Length of Catheter Use After Hysterectomy as a Risk Factor for Urinary Tract Infection.

    Science.gov (United States)

    Karp, Natalie E; Kobernik, Emily K; Kamdar, Neil S; Fore, Amanda M; Morgan, Daniel M

    2017-09-13

    The aims of this study were to determine the effect of length of postoperative catheterization on risk of urinary tract infection (UTI) and to identify risk factors for postoperative UTI. This was a retrospective case-control study. Demographic and perioperative data, including duration of indwelling catheter use and postoperative occurrence of UTI within 30 days of surgery, were analyzed for hysterectomies using the Michigan Surgical Quality Collaborative database. Catheter exposure was categorized as low-no catheter placed/catheter removed the day of surgery, intermediate-catheter removed postoperative day 1, high-catheter removal on postoperative day 2 or later, or highest-patient discharged home with catheter. A multivariable logistic regression model was developed to identify factors associated with UTI. An interaction term was included in the final model. Overall, UTI prevalence was 2.3% and increased with duration of catheter exposure (low: 1.3% vs intermediate: 2.1% vs high: 4.1% vs highest: 6.5%, P < 0.0001). High (odds ratio [OR] = 2.54 [1.51-4.27]) and highest (OR = 3.39 [1.86-6.17]) catheter exposure, operative time (OR = 1.15 [1.03-1.29]), and dependent functional status (OR = 4.62 [1.90-11.20]) were independently associated with UTI. Women who had a vaginal hysterectomy with sling/pelvic organ prolapse repair were more likely to have a UTI than those who had a vaginal hysterectomy alone (OR = 2.58 [1.10-6.07]) and more likely to have a UTI than women having an abdominal or laparoscopic hysterectomy with a sling/pelvic organ prolapse repair (OR = 2.13 [1.12-4.04]). Length of catheterization and operative time are modifiable risk factors for UTI after hysterectomy. An interaction between vaginal hysterectomy and concomitant pelvic reconstruction increases the odds of UTI.

  16. Standardizing umbilical catheter usage in preterm infants.

    Science.gov (United States)

    Shahid, Shaneela; Dutta, Sourabh; Symington, Amanda; Shivananda, Sandesh

    2014-06-01

    Absence of guidelines on umbilical arterial catheter (UAC) and umbilical venous catheter (UVC) use and inability to predict the hospital course may sway the frontline staff to overuse umbilical catheters in preterm infants. Our objective was to evaluate the feasibility of implementing guidelines standardizing the use of umbilical catheters and its impact on the incidence of sepsis and resource use. All inborn infants delivered at <33 weeks' gestation and admitted to the NICU were included in this quality improvement study. The primary outcome was proportion of infants receiving umbilical catheters. Secondary outcomes were central venous catheter (CVC) use and central line-associated bloodstream infection (CLABSI). The proportion of infants receiving UACs and UVCs was significantly lower in postintervention (sustainment) phase than in the preintervention phase (93 [42.3%] vs 52 [23.6%], P = .0001) and (137 [62.6%] vs 93 [42.3%], P = .0001), respectively. There was no corresponding increase in the proportion of infants receiving peripherally inserted central catheters (PICCs) or surgical CVCs (SCVCs) during the sustainment phase. There was a significant reduction in the proportion of infants receiving CVCs (UVC, PICC, and SCVC) in the sustainment phase. The incidence of CLABSI was similar in the preintervention and sustainment phases. Implementation of guidelines standardizing the use of umbilical catheters in the NICU is feasible. Fewer infants were exposed to the risk of UVC or UAC, and fewer resources were used. Copyright © 2014 by the American Academy of Pediatrics.

  17. Attitudes Towards Catheter Ablation for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis

    2015-01-01

    BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...

  18. Urethral catheters: can we reduce use?

    NARCIS (Netherlands)

    Broek, P.J. van den; Wille, J.C.; Benthem, B.H.B. van; Perenboom, R.J.M.; Akker-van Marle, M.E. van den; Nielen, A.M.A.

    2011-01-01

    Indwelling urinary catheters are the main cause of healthcare-associated urinary tract infections. It can be expected that reduction of the use of urinary catheters will lead to decreased numbers of urinary tract infection. The efficacy of an intervention programme to improve adherence to

  19. The efficacy of noble metal alloy urinary catheters in reducing catheter-associated urinary tract infection

    Directory of Open Access Journals (Sweden)

    Alanood Ahmed Aljohi

    2016-01-01

    Results: A 90% relative risk reduction in the rate of CAUTI was observed with the noble metal alloy catheter compared to the standard catheter (10 vs. 1 cases, P = 0.006. When considering both catheter-associated asymptomatic bacteriuria and CAUTI, the relative risk reduction was 83% (12 vs. 2 cases, P = 0.005. In addition to CAUTI, the risk of acquiring secondary bacteremia was lower (100% for the patients using noble metal alloy catheters (3 cases in the standard group vs. 0 case in the noble metal alloy catheter group, P = 0.24. No adverse events related to any of the used catheters were recorded. Conclusion: Results from this study revealed that noble metal alloy catheters are safe to use and significantly reduce CAUTI rate in ICU patients after 3 days of use.

  20. Bladder catheter protocol: technical modification for the change of Long-Term bladder catheters

    Directory of Open Access Journals (Sweden)

    Susana Rueda Pérez

    2013-09-01

    Full Text Available The replacement of urinary catheters is a common practice in chronic patients for both outpatients and inpatients. This action involves a large number of nursing interventions either planned or caused by emergency (obstruction, incorrect implantation, etc.... This modification of the catheter technique tries to improve the patient’s quality of life by minimizing the stress produced by urethral catheter replacements and reducing malpractice risks. This change in the urinary catheter technique also intends to alleviate some of the side effects of permanent urethral catheterization. By filling the bladder with saline prior to the change of catheter, it is possible to get a quick and safe implantation, dragging possible sediment and microorganisms and thereby reducing the number of nursing actions related to the process of the urinary catheter replacement (obstruction or incorrect catheter implantations etc.

  1. Mechanical Systems, Classical Models

    CERN Document Server

    Teodorescu, Petre P

    2007-01-01

    All phenomena in nature are characterized by motion; this is an essential property of matter, having infinitely many aspects. Motion can be mechanical, physical, chemical or biological, leading to various sciences of nature, mechanics being one of them. Mechanics deals with the objective laws of mechanical motion of bodies, the simplest form of motion. In the study of a science of nature mathematics plays an important role. Mechanics is the first science of nature which was expressed in terms of mathematics by considering various mathematical models, associated to phenomena of the surrounding nature. Thus, its development was influenced by the use of a strong mathematical tool; on the other hand, we must observe that mechanics also influenced the introduction and the development of many mathematical notions. In this respect, the guideline of the present book is precisely the mathematical model of mechanics. A special accent is put on the solving methodology as well as on the mathematical tools used; vectors, ...

  2. Stochastic Modelling of Energy Systems

    DEFF Research Database (Denmark)

    Andersen, Klaus Kaae

    2001-01-01

    In this thesis dynamic models of typical components in Danish heating systems are considered. Emphasis is made on describing and evaluating mathematical methods for identification of such models, and on presentation of component models for practical applications. The thesis consists of seven...... of component models, such as e.g. heat exchanger and valve models, adequate for system simulations. Furthermore, the thesis demonstrates and discusses the advantages and disadvantages of using statistical methods in conjunction with physical knowledge in establishing adequate component models of heating...... research papers (case studies) together with a summary report. Each case study takes it's starting point in typical heating system components and both, the applied mathematical modelling methods and the application aspects, are considered. The summary report gives an introduction to the scope...

  3. Microbial contamination of haemodialysis catheter connections.

    Science.gov (United States)

    Gorke, A

    2005-01-01

    Bacterial contamination and colonisation of the haemodialysis catheter is a reason for infection in dialysis patients. One reason for contamination may be frequent routine connections at the beginning, during and end of dialysis. Higher infection rates observed with double lumen catheters may be due to the absence of the sterile, disposable device that is fitted between the blood tubing and the catheter hubs with single lumen catheters. A sterile, disposable extension was implemented at the author's unit for use in dialysis with double lumen catheters. The proximal and distal ends of the extension were assessed for microbial contamination after standard dialysis. Results show microbial contamination in almost 30% of the samples retrieved from the extensions. Experiences in PD and the behaviour of skin bacteria on polymers, suggest that disposable extensions might have the potential to serve as a barrier or absorber for bacterial contamination.

  4. Effect of Catheter Gauge on the Success of Intravenous Catheter Placement by Veterinary Students.

    Science.gov (United States)

    Hofmeister, Erik H; Quandt, Jane

    2017-11-03

    The purposes of this study were to determine if senior veterinary students find it easier to place a smaller-bore catheter, and to relate patient variables with student success in catheter placement. For dogs between 10 kg and 20 kg, the catheter size options were 20 gauge or 22 gauge. For dogs larger than 20 kg, the catheter size options were 18 gauge or 20 gauge. Variables recorded included time for catheter placement, number of catheterization attempts, number of catheters used, number of legs used, difficulty of catheterization, student success, and patient characteristics including signalment, weight, body condition score, premedication drugs given, tentative diagnosis, and procedure. If the student could not place an IV catheter after three attempts, it was graded as a student catheter placement failure. For the 55 students participating in the study over 28 months, we recorded 192 individual catheterization attempts. In small patients, students were successful in 19/20 attempts with 22-gauge catheters and in 24/30 with 20-gauge catheters. In large patients, students were successful in 59/68 attempts with 20-gauge catheters and 61/74 with 18-gauge catheters. The overall success rate was 164/192 (85%). Students were more likely to be successful when attempting placement in those dogs receiving acepromazine than in those not receiving acepromazine (p=.02). There were no significant differences among any of the other variables for difficulty, placement time, number of attempts, or student success. Clinicians and educators may select a size catheter for the patient without concern for the effects on student catheter placement success.

  5. The value of percutaneous catheter cholangiography in postoperative diagnostics after biliobiliary and biliodigestive anastomoses

    International Nuclear Information System (INIS)

    Barkhausen, J.; Bidlingmaier, J.; Mueller, R.D.; Langer, R.

    1996-01-01

    Aim of study: To examine the relative importance of percutaneous catheter cholangiography in postoperative diagnostics after biliary reconstruction. Methods: 55 patients (33 males, 22 females) were subjected to 101 catheter cholangiographies. 30-50 ml of a water-soluble, iodic contrast medium were administered via an infusion system. Initial examinations were performed between the 3nd and 7th day following operation, while follow-up examinations were executed between the 8th and 145th day after surgery. The position of the catheter, the function of the anastomosis, the filling of the biliary ducts and the discharge of the contrast medium were assessed. Results: 45 examinations were inconspicuous. Drainage obstruction of the contrast medium was observed in 24 cases. Filling defects were observed in 8 examinations. A dislocation of the catheter was encountered in 5 cholangiographies while 19 examinations displayed a bile leak. Conclusion: Percutaneous catheter cholangiographies can be used to detect postoperative complications following biliary reconstruction in an easy, reliable, and cost-effective manner that also does not put too much strain on the patient. Indications for the inplementation of catheter cholangiographies are the occurrence of abdominal complaints, the clinical appearance of a peritonitis, or an increase of the serum bilirubin value. Routine examinations are recommended in conditions following liver transplantations. In addition to this, a cholangiography should be carried out prfor to the removal of the catheter. (orig.) [de

  6. A rat model of central venous catheter to study establishment of long-term bacterial biofilm and related acute and chronic infections.

    Directory of Open Access Journals (Sweden)

    Ashwini Chauhan

    Full Text Available Formation of resilient biofilms on medical devices colonized by pathogenic microorganisms is a major cause of health-care associated infection. While in vitro biofilm analyses led to promising anti-biofilm approaches, little is known about their translation to in vivo situations and on host contribution to the in vivo dynamics of infections on medical devices. Here we have developed an in vivo model of long-term bacterial biofilm infections in a pediatric totally implantable venous access port (TIVAP surgically placed in adult rats. Using non-invasive and quantitative bioluminescence, we studied TIVAP contamination by clinically relevant pathogens, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, and we demonstrated that TIVAP bacterial populations display typical biofilm phenotypes. In our study, we showed that immunocompetent rats were able to control the colonization and clear the bloodstream infection except for up to 30% that suffered systemic infection and death whereas none of the immunosuppressed rats survived the infection. Besides, we mimicked some clinically relevant TIVAP associated complications such as port-pocket infection and hematogenous route of colonization. Finally, by assessing an optimized antibiotic lock therapy, we established that our in vivo model enables to assess innovative therapeutic strategies against bacterial biofilm infections.

  7. A new central venous catheter cap: decreased microbial growth and risk for catheter-related bloodstream infection.

    Science.gov (United States)

    Buchman, A L; Spapperi, J; Leopold, P

    2009-01-01

    Catheter-related blood stream infection (CRBI) is a major cause of morbidity and mortality, and is a source of significant healthcare expenditures in patients that require central venous catheters for intravenous nutrition, chemotherapy, and other products. The source of many catheter-related infections is contamination of the catheter hub. Herein an antimicrobial catheter cap, the AB Cap is described. The AB Cap device is a catheter cleaning device designed to keep needleless luer valves clean by encapsulating them in a cleaning solution. This device was evaluated using an in vitro model of hub contamination with Staphylococcus aureus, Staphylococcus epidermidis (S. epidermidis), Klebsiella pneumonia (K. pneumonia), Pseudomonas aeruginosa, Escherichia coli and Candida albicans (C. albicans). Following hub contamination on days 1, 3, 5 and 7, saline was infused through the AB Cap and effluent collected from the efferent end. The effluent fluid was cultured for the index organisms, and allowed to incubate in culture for up to 7 days. Negative control caps were not contaminated and positive controls lacked cleaning solution and were contaminated. Microbial growth developed for all index organisms, and generally within 1 day of culture growth following the first day of contamination (day 1) in effluent from all positive controls, while no growth occurred in effluent from negative controls. No growth of any organism occurred in any of the test items after the first day of contamination. Growth of three organisms was detected in two of the three test AB Caps following contamination day 3, after 1-4 days of incubation. All organisms could be cultured in the effluent from two of the three test items at contamination day 5, generally by the second day of incubation. One test item remained free of growth for the entire test period except for one organism. By day 7, this particular test item grew an additional organism and the testing was concluded. All positive growth test

  8. Model Reduction of Hybrid Systems

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza

    for model reduction of switched systems is based on the switching generalized gramians. The reduced order switched system is guaranteed to be stable for all switching signal in this method. This framework uses stability conditions which are based on switching quadratic Lyapunov functions which are less...... conservative than the stability conditions based on common quadratic Lyapunov functions. The stability conditions which are used for this method are very useful in model reduction and design problems because they have slack variables in the conditions. Similar conditions for a class of switched nonlinear......High-Technological solutions of today are characterized by complex dynamical models. A lot of these models have inherent hybrid/switching structure. Hybrid/switched systems are powerful models for distributed embedded systems design where discrete controls are applied to continuous processes...

  9. Use of a contact force-sensing ablation catheter with advanced catheter location significantly reduces fluoroscopy time and radiation dose in catheter ablation of atrial fibrillation.

    Science.gov (United States)

    Lee, Geoffrey; Hunter, Ross J; Lovell, Matthew J; Finlay, Malcom; Ullah, Waqas; Baker, Victoria; Dhinoja, Mehul B; Sporton, Simon; Earley, Mark J; Schilling, Richard J

    2016-02-01

    The aim of this study was to evaluate the 'real-world' impact of a novel contact force (CF)-sensing (SmartTouch™, Biosense Webster, Diamond Bar, CA, USA) catheter coupled with an advanced catheter location (ACL) system on fluoroscopy time and fluoroscopy dose during atrial fibrillation (AF) ablation. This was a retrospective observational cohort study of prospectively collected data of 1515 consecutive patients undergoing paroxysmal AF (PAF) and persistent AF (PerAF) ablation at a single institution between 2009 and 2014. Patients undergoing AF ablation with the SmartTouch catheter and the ACL system (SmartTouch group, n = 510) were compared with those undergoing AF ablation without this technology (control group, n = 1005). The primary outcomes were total fluoroscopy time (min) and fluoroscopy dose as measured by the dose-area product (mGy cm(2)). Secondary endpoints included total procedure time, total ablation time, and major cardiac complications (tamponade, pericardial effusion, and urgent cardiac surgery). The SmartTouch group had significantly lower fluoroscopy times (9.5 vs. 41 min, P fluoroscopy time of 3.5 min (interquartile range 6) for all AF ablations was achieved. There was no difference in the rate of cardiac complications (∼ 1.5%). SmartTouch™ CF-sensing catheter use with ACL™ during AF ablation significantly reduces fluoroscopy times by 77%, radiation dose by 71%, and procedural time by 19% but does not improve overall safety or the risk of cardiac complications. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  10. Radiological Interventions for Correction of Central Venous Port Catheter Migrations

    International Nuclear Information System (INIS)

    Gebauer, Bernhard; Teichgraeber, Ulf Karl; Podrabsky, Petr; Werk, Michael; Haenninen, Enrique Lopez; Felix, Roland

    2007-01-01

    The purpose of the study is to evaluate radiological-interventional central venous port catheter corrections in migrated/malpositioned catheter tips. Thirty patients with migrated/malpositioned port catheter tips were included in this retrospective analysis. To visualize the catheter patency, a contrast-enhanced port catheter series was performed, followed by transfemoral port catheter correction with various 5F angiographic catheters (pigtail, Sos Omni), goose-neck snare, or combinations thereof. One patient showed spontaneous reposition of the catheter tip. In 27 of 29 patients (93%), radiological-interventional port catheter correction was successful. In two patients, port catheter malposition correction was not possible because of the inability to catch either the catheter tip or the catheter in its course, possibly due to fibrin sheath formation with attachment of the catheter to the vessel wall. No disconnection or port catheter dysfunction was observed after correction. In migrated catheter tips, radiological-interventional port catheter correction is a minimally invasive alternative to port extraction and reimplantation. In patients with a fibrin sheath and/or thrombosis, port catheter correction is often more challenging

  11. Distribution system modeling and analysis

    CERN Document Server

    Kersting, William H

    2001-01-01

    For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real understanding of the operating characteristics of a distribution system, engineers using the programs can easily make serious errors in their designs and operating procedures. Distribution System Modeling and Analysis helps prevent those errors. It gives readers a basic understanding of the modeling and operating characteristics of the major components of a distribution system. One by one, the author develops and analyzes each component as a stand-alone element, then puts them all together to analyze a distribution system comprising the various shunt and series devices for power-flow and short-circuit studies. He includes the derivation of all models and includes many num...

  12. Decreasing dialysis catheter rates by creating a multidisciplinary dialysis access program.

    Science.gov (United States)

    Rosenberry, Patricia M; Niederhaus, Silke V; Schweitzer, Eugene J; Leeser, David B

    2018-03-01

    Centers for Medicare and Medicaid Services have determined that chronic dialysis units should have central venous catheters for hemodialysis treatments. On the Eastern Shore of Maryland, the central venous catheter rates in the dialysis units averaged >45%. A multidisciplinary program was established with goals of decreasing catheter rates in order to decrease central line-associated bloodstream infections, decrease mortality associated with central line-associated bloodstream infection, decrease hospital days, and provide savings to the healthcare system. We collected the catheter rates within three dialysis centers served over a 5-year period. Using published data surrounding the incidence and related costs of central line-associated bloodstream infection and mortality per catheter day, the number of central line-associated bloodstream infection events, the costs, and the related mortality could be determined prior to and after the initiation of the dialysis access program. An organized dialysis access program resulted in a 82% decrease in the number of central venous catheter days which lead to a concurrent reduction in central line-associated bloodstream infection and deaths. As a result of creating an access program, central venous catheter rates decreased from an average rate of 45% to 8%. The cost savings related to the program was calculated to be over US$5 million. The decrease in the number of mortalities is estimated to be between 13 and 27 patients. We conclude that a formalized access program decreases catheter rates, central line-associated bloodstream infection, and the resultant hospitalizations, mortality, and costs. Areas with high hemodialysis catheter rates should develop access programs to better serve their patient population.

  13. The Impact of Tunneled Catheters for Ascites and Peritoneal Carcinomatosis on Patient Rehospitalizations

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Chuanxing [University of Pittsburgh School of Medicine, Division of Interventional Radiology, Department of Radiology (United States); Xing, Minzhi [Yale University School of Medicine, Division of Interventional Radiology, Department of Radiology and Biomedical Imaging, Yale Cancer Center (United States); Ghodadra, Anish; McCluskey, Kevin M.; Santos, Ernesto; Kim, Hyun S., E-mail: kevin.kim@yale.edu [University of Pittsburgh School of Medicine, Division of Interventional Radiology, Department of Radiology (United States)

    2016-05-15

    PurposeThe aim of the study is to assess patient outcomes, complications, impact on rehospitalizations, and healthcare costs in patients with malignant ascites treated with tunneled catheters.Materials and MethodsA total of 84 patients with malignant ascites (mean age, 60 years) were treated with tunneled catheters. Patients with peritoneal carcinomatosis and malignant ascites treated with tunneled drain catheter placement over a 3-year period were studied. Overall survival from the time of ascites and catheter placement were stratified by primary cancer and analyzed using the Kaplan–Meier method. Complications were graded by the Common Terminology Criteria for Adverse Events v3.0 (CTCAE). The differences between pre- and post-catheter admissions, hospitalizations, and Emergency Department (ED) visits, as well as related inpatient expenses were compared using paired t tests.ResultsThere were no significant differences in gender, age, or race between different primary cancer subgroups. One patient (1 %) developed bleeding (CTCAE-2). Four patients (5 %) developed local cellulitis (CTCAE-2). Three patients (4 %) had prolonged hospital stay (between 7 and 10 days) to manage ascites-related complications such as abdominal distention, discomfort, or pain. Comparison between pre- and post-catheter hospitalizations showed significantly lower admissions (−1.4/month, p < 0.001), hospital stays (−4.2/month, p = 0.003), and ED visits (−0.9/month, p = 0.002). The pre- and post-catheter treatment health care cost was estimated using MS-DRG IPPS payment system and it demonstrated significant cost savings from decreased inpatient admissions in post-treatment period (−$9535/month, p < 0.001).ConclusionsTunneled catheter treatment of malignant ascites is safe, feasible, well tolerated, and cost effective. Tunneled catheter treatment may play an important role in improving patients’ quality of life and outcomes while controlling health care expenditures.

  14. The Impact of Tunneled Catheters for Ascites and Peritoneal Carcinomatosis on Patient Rehospitalizations

    International Nuclear Information System (INIS)

    Qu, Chuanxing; Xing, Minzhi; Ghodadra, Anish; McCluskey, Kevin M.; Santos, Ernesto; Kim, Hyun S.

    2016-01-01

    PurposeThe aim of the study is to assess patient outcomes, complications, impact on rehospitalizations, and healthcare costs in patients with malignant ascites treated with tunneled catheters.Materials and MethodsA total of 84 patients with malignant ascites (mean age, 60 years) were treated with tunneled catheters. Patients with peritoneal carcinomatosis and malignant ascites treated with tunneled drain catheter placement over a 3-year period were studied. Overall survival from the time of ascites and catheter placement were stratified by primary cancer and analyzed using the Kaplan–Meier method. Complications were graded by the Common Terminology Criteria for Adverse Events v3.0 (CTCAE). The differences between pre- and post-catheter admissions, hospitalizations, and Emergency Department (ED) visits, as well as related inpatient expenses were compared using paired t tests.ResultsThere were no significant differences in gender, age, or race between different primary cancer subgroups. One patient (1 %) developed bleeding (CTCAE-2). Four patients (5 %) developed local cellulitis (CTCAE-2). Three patients (4 %) had prolonged hospital stay (between 7 and 10 days) to manage ascites-related complications such as abdominal distention, discomfort, or pain. Comparison between pre- and post-catheter hospitalizations showed significantly lower admissions (−1.4/month, p < 0.001), hospital stays (−4.2/month, p = 0.003), and ED visits (−0.9/month, p = 0.002). The pre- and post-catheter treatment health care cost was estimated using MS-DRG IPPS payment system and it demonstrated significant cost savings from decreased inpatient admissions in post-treatment period (−$9535/month, p < 0.001).ConclusionsTunneled catheter treatment of malignant ascites is safe, feasible, well tolerated, and cost effective. Tunneled catheter treatment may play an important role in improving patients’ quality of life and outcomes while controlling health care expenditures.

  15. Outcome of Radiologically Placed Tunneled Haemodialysis Catheters

    International Nuclear Information System (INIS)

    Sayani, R.; Anwar, M.; Haq, T.U.; Qamari, N.A.; Bilal, M.A.

    2013-01-01

    Objective: To study the outcome of radiologically placed double lumen tunneled haemodialysis catheters for the management of renal failure. Study Design: Case series. Place and Duration of Study: Interventional Suite of Radiology Department at the Aga Khan University Hospital, Karachi, from April 2010 to June 2011. Methodology: All consecutive patients who were referred to the department of radiology by the nephrologists for double lumen tunneled haemodialysis catheter (Permacath) placement during the study period were included. Patients with septicemia, those for whom follow-up was not available, those coming for catheter exchange or who died due to a noncatheter related condition were excluded. A radio-opaque, soft silicone double lumen catheter was inserted through a subcutaneous tunnel created over the anterior chest wall. The catheter tip was placed in the right atrium via the internal jugular vein. Ultrasound guidance was used for initial venous puncture. The rest of the procedure was carried out under fluoroscopic guidance. Technical success, catheter related bacteremia rates, adequacy of dialysis, patency, and adverse events were analyzed. Results: Overall 88 tunneled haemodialysis catheters were placed in 87 patients. Patients were followed-up for duration of 1 - 307 days with mean follow-up period of 4 months. Immediate technical success was 100%. The procedural complication rate was 5.6% (5 catheters). Eight patients died during the study period, seven from causes unrelated to the procedure. One patient died due to septicemia secondary to catheter related infection. Of the remaining 69 patients, 50 (72.4%) predominantly had uneventful course during the study period. Twelve patients developed infection (17.3%); two were successfully treated conservatively while in 10 patients catheter had to be removed. Seven catheters (10.1%) failed due to mechanical problems. In 3 patients the internal jugular veins got partially thrombosed. One catheter was

  16. Clinical Application of a New Indwelling Catheter with a Side-Hole and Spirally Arranged Shape-Memory Alloy for Hepatic Arterial Infusion Chemotherapy

    International Nuclear Information System (INIS)

    Yagihashi, Kunihiro; Takizawa, Kenji; Ogawa, Yukihisa; Okamoto, Kyoko; Yoshimatsu, Misako; Fujikawa, Atsuko; Shimamoto, Hiroshi; Nakajima, Yasuo

    2010-01-01

    A new indwelling catheter, G-spiral (GSP), was developed for hepatic arterial infusion chemotherapy (HAIC) by way of an implanted catheter-port system (CPS). Here we evaluated its physical properties and the outcomes of its clinical use. The GSP vessel-fixing power and its ability to follow a guidewire were determined with a vascular in vitro model, and Student t test was used to determine statistical significance (P < 0.05). A retrospective analysis was performed to evaluate the technical success rate and to identify the clinical complications associated with radiologic CPS implantation with GSP in 65 patients with unresectable hepatic tumors. The mean vessel-fixing power of the GSP (14.4 g) significantly differed from that of a GSP with a cut shape-memory alloy (3.3 g). The mean resistance to following the guidewire displayed by the GSP (88.5 g) was significantly less than that for a 5F W-spiral (106.3 g) or 4F Cobra-type angiographic catheter (117.8 g). The CPS was placed successfully in 64 of 65 cases (98.5%). Hepatic artery occlusion was observed in one case. Occlusion, cracking, and infection of CPS were observed in one, two, and one case, respectively. The GSP is a highly useful indwelling catheter that can be used for HAIC.

  17. Hydronic distribution system computer model

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W.; Strasser, J.J.

    1994-10-01

    A computer model of a hot-water boiler and its associated hydronic thermal distribution loop has been developed at Brookhaven National Laboratory (BNL). It is intended to be incorporated as a submodel in a comprehensive model of residential-scale thermal distribution systems developed at Lawrence Berkeley. This will give the combined model the capability of modeling forced-air and hydronic distribution systems in the same house using the same supporting software. This report describes the development of the BNL hydronics model, initial results and internal consistency checks, and its intended relationship to the LBL model. A method of interacting with the LBL model that does not require physical integration of the two codes is described. This will provide capability now, with reduced up-front cost, as long as the number of runs required is not large.

  18. Renal artery intervention using a virtual 4.5-Fr guiding catheter.

    Science.gov (United States)

    Takeshita, Satoshi; Matsumi, Junya; Saito, Shigeru

    2013-05-01

    A 6.5-Fr guiding catheter (Parent Plus 45, Medikit, Tokyo, Japan), composed of a hydrophilic sheathless guiding catheter and a dilator, has recently been developed for the treatment of renal artery stenosis. Because of its unique sheathless configuration, its outer diameter is comparable to that of a conventional 4.5-Fr introducer sheath, with the inner diameter being close in size to a 6.5-Fr guiding catheter. These features allow this sheathless system to be used as the sole guiding catheter while the arterial damage at the puncture site remains equivalent to that of a 4.5-Fr introducer sheath. We thus call this novel sheathless guiding catheter a virtual 4.5-Fr system. To demonstrate the potential of this virtual 4.5-Fr system, we report a case of renal artery stenosis successfully treated via the transradial route. This virtual 4.5-Fr system may become a viable alternative to conventional guiding catheters, and provide a favorable impact upon vascular access complications and patient morbidity. Copyright © 2012 Wiley Periodicals, Inc.

  19. Intrusion detection: systems and models

    Science.gov (United States)

    Sherif, J. S.; Dearmond, T. G.

    2002-01-01

    This paper puts forward a review of state of the art and state of the applicability of intrusion detection systems, and models. The paper also presents a classfication of literature pertaining to intrusion detection.

  20. Plant and safety system model

    International Nuclear Information System (INIS)

    Beltracchi, Leo

    1999-01-01

    The design and development of a digital computer-based safety system for a nuclear power plant is a complex process. The process of design and product development must result in a final product free of critical errors; operational safety of nuclear power plants must not be compromised. This paper focuses on the development of a safety system model to assist designers, developers, and regulators in establishing and evaluating requirements for a digital computer-based safety system. The model addresses hardware, software, and human elements for use in the requirements definition process. The purpose of the safety system model is to assist and serve as a guide to humans in the cognitive reasoning process of establishing requirements. The goals in the use of the model are to: (1) enhance the completeness of the requirements and (2) reduce the number of errors associated with the requirements definition phase of a project

  1. A clever technique for placement of a urinary catheter over a wire

    Directory of Open Access Journals (Sweden)

    Joel E Abbott

    2015-01-01

    Conclusion: Placing urinary catheters over a wire is standard practice for urologists, however, use of this technique gives the freedom of performing wire-guided catheterization in more situations than a council-tip allows. This technique facilitates successful transurethral catheterization over wire in the setting of DUC for all catheter types and styles aiding in urologic management of patients at a cost benefit to the health care system.

  2. Mathematical modeling of aeroelastic systems

    Science.gov (United States)

    Velmisov, Petr A.; Ankilov, Andrey V.; Semenova, Elizaveta P.

    2017-12-01

    In the paper, the stability of elastic elements of a class of designs that are in interaction with a gas or liquid flow is investigated. The definition of the stability of an elastic body corresponds to the concept of stability of dynamical systems by Lyapunov. As examples the mathematical models of flowing channels (models of vibration devices) at a subsonic flow and the mathematical models of protective surface at a supersonic flow are considered. Models are described by the related systems of the partial differential equations. An analytic investigation of stability is carried out on the basis of the construction of Lyapunov-type functionals, a numerical investigation is carried out on the basis of the Galerkin method. The various models of the gas-liquid environment (compressed, incompressible) and the various models of a deformable body (elastic linear and elastic nonlinear) are considered.

  3. ABSTRACT MODELS FOR SYSTEM VIRTUALIZATION

    Directory of Open Access Journals (Sweden)

    M. G. Koveshnikov

    2015-05-01

    Full Text Available The paper is dedicated to issues of system objects securing (system files and user system or application configuration files against unauthorized access including denial of service attacks. We have suggested the method and developed abstract system virtualization models, which are used toresearch attack scenarios for different virtualization modes. Estimation for system tools virtualization technology effectiveness is given. Suggested technology is based on redirection of access requests to system objects shared among access subjects. Whole and partial system virtualization modes have been modeled. The difference between them is the following: in the whole virtualization mode all copies of access system objects are created whereon subjects’ requests are redirected including corresponding application objects;in the partial virtualization mode corresponding copies are created only for part of a system, for example, only system objects for applications. Alternative solutions effectiveness is valued relating to different attack scenarios. We consider proprietary and approved technical solution which implements system virtualization method for Microsoft Windows OS family. Administrative simplicity and capabilities of correspondingly designed system objects security tools are illustrated on this example. Practical significance of the suggested security method has been confirmed.

  4. Retained Fractured Fragment of A Central Venous Catheter: A ...

    African Journals Online (AJOL)

    BACKGROUND: Complication following fracture of a central venous catheter can be catastrophic to both the patient and the attending doctor. Catheter fracture has been attributed to several factors namely prolong mechanical force acting on the catheter, and forceful removal or insertion of the catheter. CASE DETAILS: In ...

  5. Prolonged use of indwelling urinary catheter following acute urinary ...

    African Journals Online (AJOL)

    J.O. Bello

    duration of catheter use and median out-of-pocket payment per catheter change was 65 years (range 20–90 years), 12 months (range .... pocket payments per catheter change and reasons for prolonged catheter use was collected. ... ing almost half (44.7%) of the average annual income of an adult in the study region of ...

  6. Aerodynamic and Mechanical System Modelling

    DEFF Research Database (Denmark)

    Jørgensen, Martin Felix

    This thesis deals with mechanical multibody-systems applied to the drivetrain of a 500 kW wind turbine. Particular focus has been on gearbox modelling of wind turbines. The main part of the present project involved programming multibody systems to investigate the connection between forces, moments...

  7. Central venous catheters: the role of radiology

    International Nuclear Information System (INIS)

    Tan, P.L.; Gibson, M.

    2006-01-01

    The insertion and management of long-term venous catheters have long been the province of anaesthetists, intensive care physicians and surgeons. Radiologists are taking an increasing role in the insertion of central venous catheters (CVCs) because of their familiarity with the imaging equipment and their ability to manipulate catheters and guide-wires. The radiological management of the complications of CVCs has also expanded as a result. This article reviews the role of radiology in central venous access, covering the detection and management of their complications

  8. Percutaneous catheter dilatation of carotid stenoses

    International Nuclear Information System (INIS)

    Mathias, K.; Mittermayer, C.; Ensinger, H.; Neff, W.

    1980-01-01

    Thirty-one carotid artery stenoses were produced in thirty dogs by three different techniques. Twenty-three of these could be cured by transfemoral percutaneous catheter dilatation. High grade tight stenoses may present resistance which cannot be overcome by the catheter. Histological examination of the dilated vessels showed circumscribed changes in the vessel wall, with destruction of elastic membranes. From our experience of catheter dilatation of pelvic and lower limb arteries and of renal arteries, we consider it feasible to use this technique in selected patients with carotid stenosis. (orig.) [de

  9. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  10. Antimicrobial Efficacy of a New Chlorhexidine-based Device Against Staphylococcus aureus Colonization of Venous Catheters

    Science.gov (United States)

    Kowalewska, Paulina M.; Petrik, Shawn M.; Di Fiore, Attilio E.; Fox-Robichaud, Alison E.

    2018-01-01

    Vascular catheters are a major cause of nosocomial bloodstream infections. ChloraLock (ATTWILL Medical Solutions, Inc, West Jordan, UT, and ICU Medical, Inc, San Clemente, CA) is a novel antimicrobial device containing chlorhexidine digluconate (CHG) that is fitted onto a syringe and infuses CHG into the catheter lumen during locking. The objective of this study was to evaluate the antimicrobial efficacy of ChloraLock with in vitro tests and its ability to reduce Staphylococcus aureus contamination of catheters in the external jugular veins of Yorkshire swine. ChloraLock significantly reduced the bacterial load in the in vitro tests by up to 6 log10 colony-forming units (CFU) and by 3 to 4 log10 CFU/lumen in vivo in a swine model with 0.9% NaCl catheter locks. PMID:29489705

  11. Impact of balloon inflation pressure on cell viability with single and multi lumen catheters.

    Science.gov (United States)

    Dib, N; Schwalbach, D B; Plourde, B D; Kohler, R E; Dana, D; Abraham, J P

    2014-12-01

    Infusion catheters, when used in combination with balloons, are subjected to pressure created by inflation of the balloon. The compression can reduce the catheter flow area and cause elevated shear stresses in the fluid. A model and experiments were developed with a range of applied balloon pressures to investigate whether such situations may cause cell lysis during stem-cell infusion through single-lumen catheters. It was found that for balloon inflation pressures in excess of ~7 atm, it is possible for cell injury to occur, although the critical pressure depends on the fluid viscosity. The study was then applied to a multi-lumen catheter which was designed to resist compression. That device was able to handle very elevated balloon pressures and flow rates before cell lysis became a concern.

  12. Preliminary experiment with a newly developed double balloon, double lumen catheter for extracorporeal life support vascular access.

    Science.gov (United States)

    Okamoto, Taisuke; Ichinose, Keisuke; Tanimoto, Hironari; Yoshitake, Atsushi; Sakanashi, Yuji; Tashiro, Masafumi; Terasaki, Hidenori

    2003-01-01

    Recently, venovenous extracorporeal life support (VVECLS) using a double lumen catheter has been clinically used to avoid neurologic complications in the treatment of respiratory failure for neonates. However, recirculation, which is a limiting factor for oxygen delivery, still exists, and thus it does not contribute to oxygenation of the patient. We developed a newly designed double lumen catheter with a double balloon (DBDL) catheter for ECLS vascular access and performed two animal preliminary experiments in normal and hypoxic dog models (normal ventilation and one lung ventilation experiments) to investigate whether the DBDL catheter could prevent recirculation and maintain oxygen delivery to systemic circulation. The DBDL catheter (JCT Co., Hiroshima, Japan) of 15 Fr was fabricated from silicone. It consists of two lumens for drainage and return of blood with two balloons (distal and proximal balloons) that prevent oxygenated blood mixing with unoxygenated blood. VVECLS using a DBDL catheter was performed in 13 mongrel dogs (8 dogs for normal ventilation experiment weighing 12.9 +/- 1.6 kg [mean +/- SD], 5 dogs for one lung ventilation experiment weighing 16.6 +/- 2.5 kg [mean +/- SD]) under anesthesia in the two experiments. The bypass flow ranged from 10-40 ml/kg per minute in the normal ventilation experiment. VVECLS in the one lung ventilation experiment was performed with maximal bypass flow for 6 hours (ranged from 25.2 +/- 8.0-28.3 +/- 8.7 ml/kg per minute at balloon inflation and deflation). Recirculation and oxygen transfer of artificial lung with or without balloon inflation during VVECLS were studied. Recirculation decreased with balloon inflation at varied bypass flows during VVECLS in the normal ventilation experiment (varied from 1.5 +/- 14.6-12.8 +/- 16.7%) and for 6 hours after VVECLS initiation in the one lung ventilation experiment (varied from 12.2 +/- 12.2-19.2 +/- 6.5%). In particular, the values at 3 and 6 hours were significantly lower

  13. Preface: the hydra model system.

    Science.gov (United States)

    Galliot, Brigitte

    2012-01-01

    The freshwater Hydra polyp emerged as a model system in 1741 when Abraham Trembley not only discovered its amazing regenerative potential, but also demonstrated that experimental manipulations pave the way to research in biology. Since then, Hydra flourished as a potent and fruitful model system to help answer questions linked to cell and developmental biology, as such as the setting up of an organizer to regenerate a complex missing structure, the establishment and maintainance of polarity in a multicellular organism, the development of mathematical models to explain the robust developmental rules observed in this animal, the maintainance of stemness and multipotency in a highly dynamic environment, the plasticity of differentiated cells, to name but a few. However the Hydra model system is not restricted to cell and developmental biology; during the past 270 years it has also been heavily used to investigate the relationships between Hydra and its environment, opening new horizons concerning neurophysiology, innate immunity, ecosystems, ecotoxicology, symbiosis...

  14. Modeling Multi-Level Systems

    CERN Document Server

    Iordache, Octavian

    2011-01-01

    This book is devoted to modeling of multi-level complex systems, a challenging domain for engineers, researchers and entrepreneurs, confronted with the transition from learning and adaptability to evolvability and autonomy for technologies, devices and problem solving methods. Chapter 1 introduces the multi-scale and multi-level systems and highlights their presence in different domains of science and technology. Methodologies as, random systems, non-Archimedean analysis, category theory and specific techniques as model categorification and integrative closure, are presented in chapter 2. Chapters 3 and 4 describe polystochastic models, PSM, and their developments. Categorical formulation of integrative closure offers the general PSM framework which serves as a flexible guideline for a large variety of multi-level modeling problems. Focusing on chemical engineering, pharmaceutical and environmental case studies, the chapters 5 to 8 analyze mixing, turbulent dispersion and entropy production for multi-scale sy...

  15. Scale-space for empty catheter segmentation in PCI fluoroscopic images.

    Science.gov (United States)

    Bacchuwar, Ketan; Cousty, Jean; Vaillant, Régis; Najman, Laurent

    2017-07-01

    In this article, we present a method for empty guiding catheter segmentation in fluoroscopic X-ray images. The guiding catheter, being a commonly visible landmark, its segmentation is an important and a difficult brick for Percutaneous Coronary Intervention (PCI) procedure modeling. In number of clinical situations, the catheter is empty and appears as a low contrasted structure with two parallel and partially disconnected edges. To segment it, we work on the level-set scale-space of image, the min tree, to extract curve blobs. We then propose a novel structural scale-space, a hierarchy built on these curve blobs. The deep connected component, i.e. the cluster of curve blobs on this hierarchy, that maximizes the likelihood to be an empty catheter is retained as final segmentation. We evaluate the performance of the algorithm on a database of 1250 fluoroscopic images from 6 patients. As a result, we obtain very good qualitative and quantitative segmentation performance, with mean precision and recall of 80.48 and 63.04% respectively. We develop a novel structural scale-space to segment a structured object, the empty catheter, in challenging situations where the information content is very sparse in the images. Fully-automatic empty catheter segmentation in X-ray fluoroscopic images is an important and preliminary step in PCI procedure modeling, as it aids in tagging the arrival and removal location of other interventional tools.

  16. THE KISSING BALLOON TECHNIQUE WITH 2 OVER-THE-WIRE BALLOON CATHETERS THROUGH A SINGLE 8-FRENCH GUIDING CATHETER

    NARCIS (Netherlands)

    DENHEIJER, P; BERNINK, PJLM; VANDIJK, RB; TWISK, SPM; LIE, KI

    Some of the newer over-the-wire coronary angioplasty catheters have shaft sizes of 3.0 French (F) or less. The inner diameter of modern 8-F guiding catheters is large enough to accommodate two of such balloon catheters. We report a kissing balloon procedure with two over-the-wire catheters through a

  17. System Convergence in Transport Modelling

    DEFF Research Database (Denmark)

    Rich, Jeppe; Nielsen, Otto Anker; Cantarella, Guilio E.

    2010-01-01

    A fundamental premise of most applied transport models is the existence and uniqueness of an equilibrium solution that balances demand x(t) and supply t(x). The demand consists of the people that travel in the transport system and on the defined network, whereas the supply consists of the resulting...... level-of-service attributes (e.g., travel time and cost) offered to travellers. An important source of complexity is the congestion, which causes increasing demand to affect travel time in a non-linear way. Transport models most often involve separate models for traffic assignment and demand modelling...

  18. A Four Degree of Freedom Robot for Positioning Ultrasound Imaging Catheters.

    Science.gov (United States)

    Loschak, Paul M; Degirmenci, Alperen; Tenzer, Yaroslav; Tschabrunn, Cory M; Anter, Elad; Howe, Robert D

    2016-10-01

    In this paper, we present the design, fabrication, and testing of a robot for automatically positioning ultrasound (US) imaging catheters. Our system will point US catheters to provide real-time imaging of anatomical structures and working instruments during minimally invasive procedures. Manually navigating US catheters is difficult and requires extensive training in order to aim the US imager at desired targets. Therefore, a four-degree-of-freedom (4DOF) robotic system was developed to automatically navigate US imaging catheters for enhanced imaging. A rotational transmission enables 3DOF for pitch, yaw, and roll of the imager. This transmission is translated by the 4DOF. An accuracy analysis calculated the maximum allowable joint motion error. Rotational joints must be accurate to within 1.5 deg, and the translational joint must be accurate within 1.4 mm. Motion tests then validated the accuracy of the robot. The average resulting errors in positioning of the rotational joints were 0.04-0.22 deg. The average measured backlash was 0.18-0.86 deg. Measurements of average translational positioning and backlash errors were negligible. The resulting joint motion errors were well within the required specifications for accurate robot motion. The output of the catheter was then tested to verify the effectiveness of the handle motions to transmit torques and translations to the catheter tip. The catheter tip was navigated to desired target poses with average error 1.3 mm and 0.71 deg. Such effective manipulation of US imaging catheters will enable better visualization in various procedures ranging from cardiac arrhythmia treatment to tumor removal in urological cases.

  19. Intravascular catheter-related bloodstream infection.

    Science.gov (United States)

    Shah, Harshal; Bosch, Wendelyn; Thompson, Kristine M; Hellinger, Walter C

    2013-07-01

    Intravascular catheters required for the care of many hospitalized patients can give rise to bloodstream infection, a complication of care that has occurred most frequently in intensive care unit (ICU) settings. Elucidation of the pathogenesis of catheter-related bloodstream infections (CRBSIs) has guided development of effective diagnostic, management, and prevention strategies. When CRBSIs occur in the ICU, physicians must be prepared to recognize and treat them. Prevention of these infections requires careful attention to optimal catheter selection, insertion and maintenance, and to removal of catheters when they are no longer needed. This review provides a succinct summary of the epidemiology, pathogenesis, and microbiology of CRBSIs and a review of current guidance for the diagnosis, management, and prevention of these infections.

  20. Catheter-Associated Urinary Tract Infections

    Science.gov (United States)

    ... Vaccine Safety Frequently Asked Questions about Catheter-associated Urinary Tract Infections Recommend on Facebook Tweet Share Compartir What is ... an incision above the pubis. What is a urinary tract infection? A urinary tract infection (UTI) is an infection ...

  1. Peripherally inserted central catheter - dressing change

    Science.gov (United States)

    PICC - dressing change ... You have a peripherally inserted central catheter (PICC). This is a tube that goes into a vein in your arm. It carries nutrients and medicines into your body. It may also ...

  2. Persistent left superior vena cava with thrombus formed in the catheter lumen 4 h after dialysis catheter placed.

    Science.gov (United States)

    Kawasaki, Tomoki; Tanaka, Hiroyuki; Oba, Miki; Takada, Megumi; Tanaka, Haruna; Suda, Shin

    2018-02-17

    Persistent left superior vena cava (PLSVC) is one of the most common thoracic venous anomaly and rarely noticed, because it is asymptomatic. However, for nephrologists, it is frequent enough to be encountered while placing hemodialysis catheters through the jugular vein. We report the case of 66-year-old patient with PLSVC presenting intrinsic thrombosis formation 4 h after dialysis catheter placed. Dialysis catheter was placed in the left internal jugular vein without resistance and any complication. PLSVC was detected after dialysis catheter insertion. We decided to remove the catheter, because the patient has other veins in which the catheter can be placed. When it was removed 4 h after catheter placing, thrombus was recognized in the catheter lumen. Transesophageal echocardiography was performed and no thrombus formation was observed in the heart chamber. For patients with PLSVC, if there were other veins in which the catheter can be placed, catheter replacement should be considered.

  3. The outback catheter: a new device for true lumen re-entry after dissection during recanalization of arterial occlusions.

    Science.gov (United States)

    Hausegger, Klaus A; Georgieva, Borjana; Portugaller, Horst; Tauss, Josef; Stark, Gerhard

    2004-01-01

    To report the initial experience with a new catheter system (The Outback catheter) designed to allow fluoroscopically controlled re-entry of the true arterial lumen after subintimal guidewire passage during recanalization procedures of arterial occlusions. The catheter was used in 10 patients with intermittent claudication caused by chronic segmental occlusions of the superficial femoral or popliteal arteries. In all patients, conventional guidewire recanalization had failed. In 8 patients, successful true lumen re-entry was achieved with the Outback catheter. Percutaneous transluminal angioplasty was successfully performed in these patients without complications. Two technical failures occurred in heavily calcified arteries. The Outback catheter was safe and effective when used in complicated recanalization procedures in the superficial femoral and popliteal artery and the tibial trunk.

  4. Executive Information Systems' Multidimensional Models

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Executive Information Systems are design to improve the quality of strategic level of management in organization through a new type of technology and several techniques for extracting, transforming, processing, integrating and presenting data in such a way that the organizational knowledge filters can easily associate with this data and turn it into information for the organization. These technologies are known as Business Intelligence Tools. But in order to build analytic reports for Executive Information Systems (EIS in an organization we need to design a multidimensional model based on the business model from the organization. This paper presents some multidimensional models that can be used in EIS development and propose a new model that is suitable for strategic business requests.

  5. Numerical Modeling of Microelectrochemical Systems

    DEFF Research Database (Denmark)

    Adesokan, Bolaji James

    for the reactants in the bulk electrolyte that are traveling waves. The first paper presents the mathematical model which describes an electrochemical system and simulates an electroanalytical technique called cyclic voltammetry. The model is governed by a system of advection–diffusion equations with a nonlinear...... reaction term at the boundary. We investigate the effect of flow rates, scan rates, and concentration on the cyclic voltammetry. We establish that high flow rates lead to the reduced hysteresis in the cyclic voltammetry curves and increasing scan rates lead to more pronounced current peaks. The final part...... of the paper shows that the response current in a cyclic voltammetry increases proportionally to the electrolyte concentration. In the second paper we present an experiment of an electrochemical system in a microfluidc system and compare the result to the numerical solutions. We investigate how the position...

  6. System Code Models and Capabilities

    International Nuclear Information System (INIS)

    Bestion, D.

    2008-01-01

    System thermalhydraulic codes such as RELAP, TRACE, CATHARE or ATHLET are now commonly used for reactor transient simulations. The whole methodology of code development is described including the derivation of the system of equations, the analysis of experimental data to obtain closure relation and the validation process. The characteristics of the models are briefly presented starting with the basic assumptions, the system of equations and the derivation of closure relationships. An extensive work was devoted during the last three decades to the improvement and validation of these models, which resulted in some homogenisation of the different codes although separately developed. The so called two-fluid model is the common basis of these codes and it is shown how it can describe both thermal and mechanical nonequilibrium. A review of some important physical models allows to illustrate the main capabilities and limitations of system codes. Attention is drawn on the role of flow regime maps, on the various methods for developing closure laws, on the role of interfacial area and turbulence on interfacial and wall transfers. More details are given for interfacial friction laws and their relation with drift flux models. Prediction of chocked flow and CFFL is also addressed. Based on some limitations of the present generation of codes, perspectives for future are drawn.

  7. Experimental Modeling of Dynamic Systems

    DEFF Research Database (Denmark)

    Knudsen, Morten Haack

    2006-01-01

    An engineering course, Simulation and Experimental Modeling, has been developed that is based on a method for direct estimation of physical parameters in dynamic systems. Compared with classical system identification, the method appears to be easier to understand, apply, and combine with physical...... insight. It is based on a sensitivity approach that is useful for choice of model structure, for experiment design, and for accuracy verification. The method is implemented in the Matlab toolkit Senstools. The method and the presentation have been developed with generally preferred learning styles in mind...

  8. Pulsatile flow in ventricular catheters for hydrocephalus

    Science.gov (United States)

    Giménez, Á.; Galarza, M.; Thomale, U.; Schuhmann, M. U.; Valero, J.; Amigó, J. M.

    2017-05-01

    The obstruction of ventricular catheters (VCs) is a major problem in the standard treatment of hydrocephalus, the flow pattern of the cerebrospinal fluid (CSF) being one important factor thereof. As a first approach to this problem, some of the authors studied previously the CSF flow through VCs under time-independent boundary conditions by means of computational fluid dynamics in three-dimensional models. This allowed us to derive a few basic principles which led to designs with improved flow patterns regarding the obstruction problem. However, the flow of the CSF has actually a pulsatile nature because of the heart beating and blood flow. To address this fact, here we extend our previous computational study to models with oscillatory boundary conditions. The new results will be compared with the results for constant flows and discussed. It turns out that the corrections due to the pulsatility of the CSF are quantitatively small, which reinforces our previous findings and conclusions. This article is part of the themed issue `Mathematical methods in medicine: neuroscience, cardiology and pathology'.

  9. Compositional Modeling of Biological Systems

    OpenAIRE

    Zámborszky, Judit

    2010-01-01

    Molecular interactions are wired in a fascinating way resulting in complex behavior of bio-logical systems. Theoretical modeling provides us a useful framework for understanding the dynamics and the function of such networks. The complexity of the biological systems calls for conceptual tools that manage the combinatorial explosion of the set of possible interac-tions. A suitable conceptual tool to attack complexity is compositionality, already success-fully used in the process algebra field ...

  10. Peritoneal catheter fixation combined with straight upward tunnel and low implant position to prevent catheter malfunction.

    Science.gov (United States)

    Zhang, Qingyan; Jiang, Chunming; Zhu, Wei; Sun, Cheng; Xia, Yangyang; Tang, Tianfeng; Wan, Cheng; Shao, Qiuyuan; Liu, Jing; Jin, Bo; Zhang, Miao

    2018-03-01

    Catheter malfunction is the main reason for early peritoneal dialysis (PD) technique failure. This study aimed to evaluate the effect of a new surgery technique with catheter fixation to the lower abdominal wall combined with straight upward tunnel and low implant position in reducing catheter malfunction. Patients with end stage renal disease who received PD in our centre from January 2013 to December 2015 were involved in this study. They were randomly divided into three groups according to surgical technique: traditional open surgery group, modified open surgery group and modified open surgery with catheter fixation group. All patients were followed up for six months after surgery. Catheter- related complications were analyzed. A total of 152 patients were involved. Among them, 49 received traditional open surgery (TOS group), 49 received modified open surgery (MOS group), and 54 received modified open surgery with catheter fixation (MOS-F group). During follow-up, no patients (0%) in MOS-F group developed catheter malfunction which was significantly lower than that of the TOS group (0 vs 16.33%, P = 0.002). Although not statistically significant, the incidence of catheter malfunction was lower in MOS-F group than that in MOS group (0 vs 4.08%, P = 0.134). No significant difference was observed in the episodes of infection, bleeding, leakage, inflow or outflow pain, hernia and delayed wound healing among the three groups (all P > 0.05). Catheter fixation combined with straight upward tunnel and low implant position can effectively prevent catheter malfunction in PD catheter placement. © 2016 Asian Pacific Society of Nephrology.

  11. Control of pathogen growth and biofilm formation using a urinary catheter that releases antimicrobial nitrogen oxides.

    Science.gov (United States)

    Kishikawa, Hiroaki; Ebberyd, Anette; Römling, Ute; Brauner, Annelie; Lüthje, Petra; Lundberg, Jon O; Weitzberg, Eddie

    2013-12-01

    Antibacterial nitrogen oxides including nitric oxide are formed from nitrite under acidic conditions. In a continuous-flow model of the urinary bladder we used the retention cuff of an all-silicone Foley catheter as a depot for export of nitrogen oxides. The cuff was filled with sodium nitrite (50mM) and an acidic buffer solution (pH 3.6) and the growth of nine common uropathogens in the surrounding artificial urine was measured along with biofilm formation on the catheter surface. In experiments with control catheters (NaCl) bacteria grew readily and biofilm developed within hours in five of nine strains. In contrast, with test catheters bacterial counts were markedly reduced and biofilm formation by Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter cloace was prevented, whereas Escherichia coli and Staphylococcus aureus were unaffected. We conclude that antibacterial nitrogen oxides generated in the retention cuff of a urinary catheter diffuse into urine and prevent the growth of urinary pathogens and biofilm formation. Although promising, future studies will reveal if this novel approach can be clinically useful for the prevention of catheter-associated urinary tract infections. © 2013 Elsevier Inc. All rights reserved.

  12. Risk Factors for Catheter Associated Urinary Tract Infections in a Pediatric Institution.

    Science.gov (United States)

    Lee, Nora G; Marchalik, Daniel; Lipsky, Andrew; Rushton, H Gil; Pohl, Hans G; Song, Xiaoyan

    2016-04-01

    Catheter associated urinary tract infections are an essential measure for health care quality improvement that affects reimbursement through hospital acquired condition reduction programs in adult patients. With the mounting importance of preventing such infections we evaluated risk factors for acquiring catheter associated urinary tract infections in pediatric patients. All catheter associated urinary tract infections were identified at 1 pediatric institution from September 2010 to August 2014 from a prospective database maintained by the infection control office. To identify risk factors patients with a catheter associated urinary tract infection were individually matched to control patients with a urinary catheter but without infection by age, gender, date and the hospital location of the infection in 1:2 fashion. A total of 50 patients with catheter associated urinary tract infection were identified and matched to 100 control patients. Compared to controls the patients with infection were more likely to have a catheter in place for longer (2.9 days, OR 1.08, 95% CI 1.01, 1.15, p = 0.02). They were also more likely to be on contact precautions (OR 4.00, 95% CI 1.73, 9.26, p = 0.001), and have concurrent infections (OR 3.04, 95% CI 1.39, 6.28, p = 0.005) and a history of catheterization (OR 3.24, 95% CI 1.55, 6.77, p = 0.002). Using a conditional multivariate regression model the 3 most predictive variables were duration of catheter drainage, contact isolation status and history of catheterization. Longer duration of urinary catheter drainage, positive contact precautions status and a history of catheterization appear to be associated with a higher risk of catheter associated urinary tract infection in hospitalized pediatric patients. Physicians should attempt to decrease the duration of catheterization, especially in patients who meet these criteria, to minimize the risk of catheter associated urinary tract infection. Copyright © 2016 American Urological

  13. How much is catheter flow influenced by the use of closed luer lock access devices?

    Science.gov (United States)

    Eloot, Sunny; De Vos, Jean-Yves; Hombrouckx, Remi; Verdonck, Pascal

    2007-10-01

    To reduce infection risks in patients on hemodialysis with a long term central venous catheter, different types of closed luer lock access devices are used on the arterial and venous catheter hub. Although those connectors create a mechanically and microbiologically closed system in between two dialysis sessions, no data are available on the resistance those connectors exert on the blood flow during dialysis. Therefore, in the present study, flow resistance was determined in three different connectors. In an in vitro setup, different connectors were attached in between a male (Bellco BL 307 dialysis tubing) and female luer: BD Q-Syte (Becton-Dickinson, Utah, USA), second edition Tego (ICU Medical, CA, USA), and Swan-LockU connector (Codan, Lensahn, Germany). For a wide range of water flow rates, pressure-flow relationships were measured, simulating catheter inflow as well as catheter outflow, by reversing the flow direction. Resistances were compared to a simple male-female connection, as in a standard bloodline-catheter connection, and mathematical corrections were performed for the use of water instead of blood. For a blood flow of 500 mL/min, simulating clinical dialysis, the additional pressure drop is 118 mmHg (Becton Dickinson), 52 mmHg (Codan), and 23 mmHg (Tego) in the case of catheter inflow, while it is 74 mmHg (Becton Dickinson), 40 mmHg (Codan), and 27 mmHg (Tego) in the case of catheter outflow. Resistances are also depending on the type of tubing as used during dialysis. In conclusion, the Tego and Codan connector show promising results for the use on a catheter hub during and in between dialysis sessions. Whether those resistances are in the safe range without the incidence of blood hemolysis will soon be investigated in an in vivo study.

  14. Complications catheter-related infections in patients on hemodialysis (septic infections of patients on hemodialysis

    Directory of Open Access Journals (Sweden)

    Knežević Violeta

    2017-01-01

    Full Text Available Introduction: Hemodialysis catheters are used for quick establishing of an adequate vascular approach, when urgent hemodialysis is indicated in time of maturation of artery-vein fistula and in patients in whom all other vascular approach have been exhausted. Although the placement of the catheter provides the necessary vascular access, carries a risk of both local-infection exit site of a catheter, as well as systemic complications, including catheter-related infection, septic thrombophlebitis, endocarditis, and other metastatic infections such as lung abscess and brain, osteomyelitis and endophthalmitis. Cases series: We have presented a retrospective series of 5 cases of hemodialysis patients hospitalized at the Clinic of Nephrology and Clinical Immunology, of the Clinical Center of Vojvodina in the period of 2010 to 2017, which have developed different complications of catheter-related infections. Three patients diagnosed with spondylodiscitis and endocarditis in two. In one patient with native valve endocarditis, due to the appearance of other complications, there was a death, while the other patients had an adequate response to therapy. Conclusion: Early recognition of potential complications of catheter-related infections to more successful treatment of these patients.

  15. Novel automated point collection software facilitates rapid, high-density electroanatomical mapping with multiple catheter types.

    Science.gov (United States)

    Ptaszek, Leon M; Moon, Boyce; Rozen, Guy; Mahapatra, Srijoy; Mansour, Moussa

    2018-01-01

    Manual, point-by-point electroanatomical mapping requires the operator to directly evaluate each point during map construction. Consequently, point collection can be a slow process. An automated 3D mapping system was developed with the goal of improving key mapping metrics, including map completion time and point density. Automated 3D mapping software that includes morphology and cycle length discrimination functions for surface and intracardiac electrograms was developed. In five swine, electroanatomical maps (EAMs) of all four cardiac chambers were generated in sinus rhythm. Four catheters were used: two different four-pole ablation catheters, a 20-pole circular catheter, and a 64-pole basket catheter. Automated and manual 3D mapping were compared for 12 different catheter-chamber combinations (paired sets of 10 maps for most combinations, for a total of 156 maps). Automated 3D mapping produced more than twofold increase in the number of points per map, as compared with manual 3D mapping (P ≤0.007 for all catheter-chamber combinations tested). Automated 3D mapping also reduced map completion time by an average of 29% (P software described in this study is significantly faster than manual, point-by-point 3D mapping. This resulted in shorter mapping time and higher point density. The morphology discrimination functions effectively excluded ectopic beats during mapping in sinus rhythm and allowed for rapid mapping of intermittent ventricular ectopic beats. © 2017 Wiley Periodicals, Inc.

  16. Test method for mechanical properties of implantable catheters according to DIN 10555-3.

    Science.gov (United States)

    Busch, J D; Schröder, H; Sellenschloh, K; Adam, G; Ittrich, H; Huber, G

    2018-03-22

    To enable causal analysis of port catheter failure, this study aimed to develop an experimental setup for uniaxial tensile tests that addresses the specific requirements of highly elastic medical catheters; and to quantify parameters of the catheters' mechanical competence with respect to effects of artificial aging. Segments of 6F-polyurethane catheters were tested in their native status, after chemical and after mechanical aging. Tension experiments were performed with a rate of 220 mm/min until catheter failure. Material behavior was analyzed based on load cell measurements of the universal test system and an additional optical distance registration. The Young's modulus, the ultimate stress and the ultimate strain were determined. Chemical aging significantly decreased Young's modulus (84%; p = 0.001) and ultimate stress (83%; p < 0.001), whereas mechanical aged samples demonstrated similar results for the Young's modulus (p = 0.772) and a non-significant rise of ultimate stress (13%; p = 0.128). Ultimate strain did not differ significantly regardless of the pretreatment. The results proof reliability, reproducibility and sensitivity to quantify artificial aging induced variations and also promise to detect deviations in material features caused by long-term clinical usage of catheters. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Bacillus Cereus catheter related bloodstream infection in a patient in a patient with acute lymphblastic leukemia

    Directory of Open Access Journals (Sweden)

    Lütfiye Öksüz

    2012-01-01

    Full Text Available Bacillus cereus infection is rarely associated with actual infection and for this reason single positive blood culture is usually regarded as contamination . However it may cause a number of infections, such catheter-related blood stream infections. Significant catheter-related bloodstream infections (CRBSI caused by Bacillus spp. are mainly due to B.cereus and have been predominantly reported in immunocompromised hosts1 . Catheter removal is generally advised for management of infection. In this report, catheter-related bacteremia caused by B.cereus in a patient with acute lymphoblastıc leukemia (ALL in Istanbul Medical Faculty was presented.A 44-year old man presented with fatigue, weight loss, epistaxis and high fever. A double-lumen Hickman–catheter (Bard 12.0 Fr, Round Dual Lumen was inserted by surgical cut-down to access the right subclavian vein which would be necessary for allogeneic stem cell transplantation. Three weeks later the patient presented with high fever and headache. Bacillus spp. was isolated from the cathether while blood culture obtained from the peripheral vein remained negative. The bacterial identification was confirmed as B.cereus using VITEK identification system It has been reported Bacillus cereus septicemia may be fatal in immunocompromised hosts despite broad-spectrum appropriate treatment10. Catheter removal is essential for prevention of recurrent bacteremia. Long-term cathater salvage should be reserved for appropriate patient group.

  18. Parametric Modeling for Fluid Systems

    Science.gov (United States)

    Pizarro, Yaritzmar Rosario; Martinez, Jonathan

    2013-01-01

    Fluid Systems involves different projects that require parametric modeling, which is a model that maintains consistent relationships between elements as is manipulated. One of these projects is the Neo Liquid Propellant Testbed, which is part of Rocket U. As part of Rocket U (Rocket University), engineers at NASA's Kennedy Space Center in Florida have the opportunity to develop critical flight skills as they design, build and launch high-powered rockets. To build the Neo testbed; hardware from the Space Shuttle Program was repurposed. Modeling for Neo, included: fittings, valves, frames and tubing, between others. These models help in the review process, to make sure regulations are being followed. Another fluid systems project that required modeling is Plant Habitat's TCUI test project. Plant Habitat is a plan to develop a large growth chamber to learn the effects of long-duration microgravity exposure to plants in space. Work for this project included the design and modeling of a duct vent for flow test. Parametric Modeling for these projects was done using Creo Parametric 2.0.

  19. A Fast pH-Switchable and Self-Healing Supramolecular Hydrogel Carrier for Guided, Local Catheter Injection in the Infarcted Myocardium

    OpenAIRE

    Bastings, Maartje M. C.; Koudstaal, Stefan; Kieltyka, Roxanne E.; Nakano, Yoko; Pape, A. C. H.; Feyen, Dries A. M.; van Slochteren, Frebus J.; Doevendans, Pieter A.; Sluijter, Joost P. G.; Meijer, E. W.; Chamuleau, Steven A. J.; Dankers, Patricia Y. W.

    2014-01-01

    Minimally invasive intervention strategies after myocardial infarction use state-of-the-art catheter systems that are able to combine mapping of the infarcted area with precise, local injection of drugs. To this end, catheter delivery of drugs that are not immediately pumped out of the heart is still challenging, and requires a carrier matrix that in the solution state can be injected through a long catheter, and instantaneously gelates at the site of injection. To address this unmet need, a ...

  20. Pacemaker implantation after catheter ablation for atrial fibrillation.

    Science.gov (United States)

    Deshmukh, Abhishek J; Yao, Xiaoxi; Schilz, Stephanie; Van Houten, Holly; Sangaralingham, Lindsey R; Asirvatham, Samuel J; Friedman, Paul A; Packer, Douglas L; Noseworthy, Peter A

    2016-01-01

    Sinus node dysfunction requiring pacemaker implantation is commonly associated with atrial fibrillation (AF), but may not be clinically apparent until restoration of sinus rhythm with ablation or cardioversion. We sought to determine frequency, time course, and predictors for pacemaker implantation after catheter ablation, and to compare the overall rates to a matched cardioversion cohort. We conducted a retrospective analysis using a large US commercial insurance database and identified 12,158 AF patients who underwent catheter ablation between January 1, 2005 and December 31, 2012. Over an average of 2.4 years of follow-up, 5.6 % of the patients underwent pacemaker implantation. Using the Cox proportional hazards models, we found that risk of risks of pacemaker implantation was associated with older age (50-64 and ≥65 versus pacemaker implantation between ablation patients and propensity score (PS)-matched cardioversion groups (3.5 versus. 4.1 % at 1 year and 8.8 versus 8.3 % at 5 years). Overall, pacemaker implantation occurs in about 1/28 patients within 1 year of catheter ablation. The overall implantation rate decreased between 2005 and 2012. Furthermore, the risk after ablation is similar to cardioversion, suggesting that patients require pacing due to a common underlying electrophysiologic substrate, rather than the ablation itself.

  1. Model checking embedded system designs

    NARCIS (Netherlands)

    Brinksma, Hendrik; Mader, Angelika H.

    2002-01-01

    Model checking has established itself as a successful tool supported technique for the verification and debugging of various hardware and software systems [16]. Not only in academia, but also by industry this technique is increasingly being regarded as a promising and practical proposition,

  2. GENERIC model for multiphase systems

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2010-01-01

    GENERIC is a nonequilibrium thermodynamic formalism in which the dynamic behavior of a system is described by a single compact equation involving two types of brackets: a Poisson bracket and a dissipative bracket. This formalism has proved to be a very powerful instrument to model the dynamic

  3. An extensible analysable system model

    DEFF Research Database (Denmark)

    Probst, Christian W.; Hansen, Rene Rydhof

    2008-01-01

    Analysing real-world systems for vulnerabilities with respect to security and safety threats is a difficult undertaking, not least due to a lack of availability of formalisations for those systems. While both formalisations and analyses can be found for artificial systems such as software......, this does not hold for real physical systems. Approaches such as threat modelling try to target the formalisation of the real-world domain, but still are far from the rigid techniques available in security research. Many currently available approaches to assurance of critical infrastructure security...... are based on (quite successful) ad-hoc techniques. We believe they can be significantly improved beyond the state-of-the-art by pairing them with static analyses techniques. In this paper we present an approach to both formalising those real-world systems, as well as providing an underlying semantics, which...

  4. Radio-nuclide angiocardiography combined with Swan-Ganz catheter for the estimation of volume-pressure curves of the pulmonary ''venous'' system in man

    International Nuclear Information System (INIS)

    Gotoh, K.; Hirakawa, S.; Suzuki, T.; Fujiwara, H.; Ohsumi, Y.; Yagi, Y.

    1983-01-01

    Short segments of volume-pressure (V-P) curves of the pulmonary ''venous'' (P''V'') system, consisting of the pulmonary veins and left atrium, were estimated in 31 patients. Pulmonary blood volume (PBV) was estimated by our new method, using RN-angiocardiography. Increments in PBV and mean pulmonary artery wedge (PAW) pressure, that occur during passive-elevation of both legs, were clues to the estimation of the compliance (ΔV/ΔP) of this system. Sublingual administration of nitroglycerin (NTG) caused the short segments of V-P curves to shift to the left almost horizontally but slightly downwards, associated with a considerable increase in ΔV/ΔP. It is suggested that NTG causes, among other things, relaxation of the walls of P''V'' system

  5. Systems modeling for laser IFE

    Science.gov (United States)

    Meier, W. R.; Raffray, A. R.; Sviatoslavsky, I. N.

    2006-06-01

    A systems model of a laser-driven IFE power plant is being developed to assist in design trade-offs and optimization. The focus to date has been on modeling the fusion chamber, blanket and power conversion system. A self-consistent model has been developed to determine key chamber and thermal cycle parameters (e.g., chamber radius, structure and coolant temperatures, cycle efficiency, etc.) as a function of the target yield and pulse repetition rate. Temperature constraints on the tungsten armor, ferritic steel wall, and structure/coolant interface are included in evaluating the potential design space. Results are presented for a lithium cooled first wall coupled with a Brayton power cycle. LLNL work performed under the auspices of the US Department of Energy by the University of California LLNL under Contract W-7405-Eng-48.

  6. Clinical usefulness of catheter-drawn blood samples and catheter tip cultures for the diagnosis of catheter-related bloodstream infections in neonatology: A systematic review.

    Science.gov (United States)

    Ferreira, Janita; Camargos, Paulo Augusto Moreira; Clemente, Wanessa Trindade; Romanelli, Roberta Maia de Castro

    2018-01-01

    Neonatal sepsis is the most frequent health care-associated infection in neonatal units. This study aimed to analyze articles on the clinical usefulness of catheter-drawn blood samples and catheter tip cultures for the diagnosis of intravascular catheter-related bloodstream infection (CRBSI) in neonates. A systematic search was performed for studies published from 1987-2017, without language restriction. Observational studies carried out in neonates with CRBSI diagnosed using catheter-drawn blood samples or catheter tip cultures were included. A total of 412 articles were identified in the databases and 10 articles were included. The 7 studies that evaluated central venous catheter tip cultures and cultures of catheter fragments presented sensitivities ranging from 58.5%-100% and specificities ranging from 60%-95.7%. Three studies that evaluated catheter-drawn blood cultures, paired with peripheral blood cultures, reported sensitivity and specificity of 94% and 71% when evaluated for the differential time to positivity. When quantitative evaluation was performed, the sensitivity and specificity were 80% and 99.4%. Most of the studies analyzed cultures from the central venous catheter tip and catheter fragments for the diagnosis of CRBSI in neonatal populations. The results of this review suggest that the analysis of the catheter-drawn blood samples and catheter tip cultures, paired with peripheral blood cultures, are efficient methods for the diagnosis of CRBSI in neonates. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  7. Magnetic resonance evaluation of renal artery stenosis in a swine model: performance of low-dose gadobutrol versus gadoterate meglumine in comparison with digital subtraction intra-arterial catheter angiography.

    Science.gov (United States)

    Morelli, John N; Runge, Val M; Ai, Fei; Zhang, Wei; Li, Xiaoming; Schmitt, Peter; McNeal, Gary; Miller, Matthew; Lennox, Mark; Wusten, Oliver; Schoenberg, Stefan O; Attenberger, Ulrike I

    2012-06-01

    The aim of this study was to compare low-dose imaging with gadobutrol and gadoterate meglumine (Gd-DOTA) for evaluation of renal artery stenosis with 3-T magnetic resonance angiography (MRA) in a swine model. A total of 12 experimental animals were evaluated using equivalently dosed gadobutrol and Gd-DOTA for time-resolved and static imaging. For time-resolved imaging, the time-resolved imaging with stochastic trajectories (TWIST) technique (temporal footprint, 4.4 seconds) was used; a dose of 1 mL of gadobutrol was injected at 2 mL/s and a dose of 2 mL of Gd-DOTA was injected at both 2 and 4 mL/s. For a separate static acquisition, doses were doubled. The static scans were used for stenosis gradation and the time-resolved scans for comparison of enhancement dynamics, signal-to-noise ratio (SNR), and qualitative assessments. The average magnitude of difference in the stenosis measurements with static gadobutrol scans relative to digital subtraction intra-arterial catheter angiography (mean [SD], 7.4% [5.6%]) was less than with both the 2 mL/s (10.6% [6.2%]) and 4 mL/s (11.5% [7.8%]) Gd-DOTA MRA protocols. On time-resolved scans, peak signal-to-noise ratio was greatest with the gadobutrol protocol (P < 0.05), and the gadobutrol TWIST scan was preferred to the TWIST Gd-DOTA scan in terms of image quality and stenosis visualization in every case for every reader. Low-dose gadobutrol (~0.05 mmoL/kg) contrast-enhanced MRA results in improved accuracy of renal artery stenosis assessments relative to equivalently dosed Gd-DOTA at 3 T.

  8. Cotangent Models for Integrable Systems

    Science.gov (United States)

    Kiesenhofer, Anna; Miranda, Eva

    2017-03-01

    We associate cotangent models to a neighbourhood of a Liouville torus in symplectic and Poisson manifolds focusing on b-Poisson/ b-symplectic manifolds. The semilocal equivalence with such models uses the corresponding action-angle theorems in these settings: the theorem of Liouville-Mineur-Arnold for symplectic manifolds and an action-angle theorem for regular Liouville tori in Poisson manifolds (Laurent- Gengoux et al., IntMath Res Notices IMRN 8: 1839-1869, 2011). Our models comprise regular Liouville tori of Poisson manifolds but also consider the Liouville tori on the singular locus of a b-Poisson manifold. For this latter class of Poisson structures we define a twisted cotangent model. The equivalence with this twisted cotangent model is given by an action-angle theorem recently proved by the authors and Scott (Math. Pures Appl. (9) 105(1):66-85, 2016). This viewpoint of cotangent models provides a new machinery to construct examples of integrable systems, which are especially valuable in the b-symplectic case where not many sources of examples are known. At the end of the paper we introduce non-degenerate singularities as lifted cotangent models on b-symplectic manifolds and discuss some generalizations of these models to general Poisson manifolds.

  9. Comparison between radiation exposure levels using an image intensifier and a flat-panel detector-based system in image-guided central venous catheter placement in children weighing less than 10 kg

    Energy Technology Data Exchange (ETDEWEB)

    Miraglia, Roberto; Maruzzelli, Luigi; Cortis, Kelvin; Gerasia, Roberta; Maggio, Simona; Luca, Angelo [Diagnostic and Therapeutic Services, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy); Piazza, Marcello [Department of Anesthesia, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy); Tuzzolino, Fabio [Department of Information Technology, Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Palermo (Italy)

    2014-09-10

    Ultrasound-guided central venous puncture and fluoroscopic guidance during central venous catheter (CVC) positioning optimizes technical success and lowers the complication rates in children, and is therefore considered standard practice. The purpose of this study was to compare the radiation exposure levels recorded during CVC placement in children weighing less than 10 kg in procedures performed using an image intensifier-based angiographic system (IIDS) to those performed in a flat-panel detector-based interventional suite (FPDS). A retrospective review of 96 image-guided CVC placements, between January 2008 and October 2013, in 49 children weighing less than 10 kg was performed. Mean age was 8.2 ± 4.4 months (range: 1-22 months). Mean weight was 7.1 ± 2.7 kg (range: 2.5-9.8 kg). The procedures were classified into two categories: non-tunneled and tunneled CVC placement. Thirty-five procedures were performed with the IIDS (21 non-tunneled CVC, 14 tunneled CVC); 61 procedures were performed with the FPDS (47 non-tunneled CVC, 14 tunneled CVC). For non-tunneled CVC, mean DAP was 113.5 ± 126.7 cGy cm{sup 2} with the IIDS and 15.9 ± 44.6 cGy . cm{sup 2} with the FPDS (P < 0.001). For tunneled CVC, mean DAP was 84.6 ± 81.2 cGy . cm{sup 2} with the IIDS and 37.1 ± 33.5 cGy cm{sup 2} with the FPDS (P = 0.02). The use of flat-panel angiographic equipment reduces radiation exposure in small children undergoing image-guided CVC placement. (orig.)

  10. Graph modeling systems and methods

    Science.gov (United States)

    Neergaard, Mike

    2015-10-13

    An apparatus and a method for vulnerability and reliability modeling are provided. The method generally includes constructing a graph model of a physical network using a computer, the graph model including a plurality of terminating vertices to represent nodes in the physical network, a plurality of edges to represent transmission paths in the physical network, and a non-terminating vertex to represent a non-nodal vulnerability along a transmission path in the physical network. The method additionally includes evaluating the vulnerability and reliability of the physical network using the constructed graph model, wherein the vulnerability and reliability evaluation includes a determination of whether each terminating and non-terminating vertex represents a critical point of failure. The method can be utilized to evaluate wide variety of networks, including power grid infrastructures, communication network topologies, and fluid distribution systems.

  11. Endovascular Catheter for Magnetic Navigation under MR Imaging Guidance: Evaluation of Safety in Vivo at 1.5T

    Science.gov (United States)

    Hetts, S.W.; Saeed, M.; Martin, A.J.; Evans, L.; Bernhardt, A.F.; Malba, V.; Settecase, F.; Do, L.; Yee, E.J.; Losey, A.; Sincic, R.; Roy, S.; Arenson, R.L.; Wilson, M.W.

    2013-01-01

    BACKGROUND AND PURPOSE: Endovascular navigation under MR imaging guidance can be facilitated by a catheter with steerable microcoils on the tip. Not only do microcoils create visible artifacts allowing catheter tracking, but also they create a small magnetic moment permitting remote-controlled catheter tip deflection. A side product of catheter tip electrical currents, however, is the heat that might damage blood vessels. We sought to determine the upper boundary of electrical currents safely usable at 1.5T in a coil-tipped microcatheter system. MATERIALS AND METHODS: Alumina tubes with solenoid copper coils were attached to neurovascular microcatheters with heat shrink-wrap. Catheters were tested in carotid arteries of 8 pigs. The catheters were advanced under x-ray fluoroscopy and MR imaging. Currents from 0 mA to 700 mA were applied to test heating and potential vascular damage. Postmortem histologic analysis was the primary endpoint. RESULTS: Several heat-mitigation strategies demonstrated negligible vascular damage compared with control arteries. Coil currents ≤300 mA resulted in no damage (0/58 samples) compared with 9 (25%) of 36 samples for > 300-mA activations (P = .0001). Tip coil activation ≤1 minute and a proximal carotid guide catheter saline drip > 2 mL/minute also had a nonsignificantly lower likelihood of vascular damage. For catheter tip coil activations ≤300 mA for ≤1 minute in normal carotid flow, 0 of 43 samples had tissue damage. CONCLUSIONS: Activations of copper coils at the tip of microcatheters at low currents in 1.5T MR scanners can be achieved without significant damage to blood vessel walls in a controlled experimental setting. Further optimization of catheter design and procedure protocols is necessary for safe remote control magnetic catheter guidance. PMID:23846795

  12. Types of urethral catheter for reducing symptomatic urinary tract infections in hospitalised adults requiring short-term catheterisation: multicentre randomised controlled trial and economic evaluation of antimicrobial- and antiseptic-impregnated urethral catheters (the CATHETER trial).

    Science.gov (United States)

    Pickard, R; Lam, T; Maclennan, G; Starr, K; Kilonzo, M; McPherson, G; Gillies, K; McDonald, A; Walton, K; Buckley, B; Glazener, C; Boachie, C; Burr, J; Norrie, J; Vale, L; Grant, A; N'dow, J

    2012-11-01

    Catheter-associated urinary tract infection (CAUTI) is a major preventable cause of harm for patients in hospital and incurs significant costs for health-care providers such as the UK NHS. Many preventative strategies and measures have been introduced to minimise CAUTI risk, including the use of antimicrobial catheters. However, there is considerable uncertainty regarding their usefulness in terms of reducing symptomatic CAUTI, and whether or not they are cost-effective. Do antimicrobial catheters reduce the rate of symptomatic urinary tract infection (UTI) during short-term hospital use and is their use cost-effective for the UK NHS? A pragmatic multicentre UK randomised controlled trial comparing three catheters as they would be used in the UK NHS: antimicrobial-impregnated (nitrofurazone) and antiseptic-coated (silver alloy) catheters with the standard polytetrafluoroethylene (PTFE)-coated catheters. Economic evaluation used a decision model populated with data from the trial. Sensitivity analysis was used to explore uncertainty. Relevant clinical departments in 24 NHS hospitals throughout the UK. Adults requiring temporary urethral catheterisation for a period of between 1 and 14 days as part of their care, predominantly as a result of elective surgery. Eligible participants were randomised 1 : 1 : 1 to one of three types of urethral catheter in order to make the following pragmatic comparisons: nitrofurazone-impregnated silicone catheter compared with standard PTFE-coated latex catheter; and silver alloy-coated hydrogel latex catheter compared with standard PTFE-coated latex catheter. The primary outcome for clinical effectiveness was the incidence of UTI at any time up to 6 weeks post randomisation. This was defined as any symptom reported during catheterisation, up to 3 days or 1 or 2 weeks post catheter removal or 6 weeks post randomisation combined with a prescription of antibiotics, at any of these times, for presumed symptomatic UTI. The primary economic

  13. Probabilistic models for feedback systems.

    Energy Technology Data Exchange (ETDEWEB)

    Grace, Matthew D.; Boggs, Paul T.

    2011-02-01

    In previous work, we developed a Bayesian-based methodology to analyze the reliability of hierarchical systems. The output of the procedure is a statistical distribution of the reliability, thus allowing many questions to be answered. The principal advantage of the approach is that along with an estimate of the reliability, we also can provide statements of confidence in the results. The model is quite general in that it allows general representations of all of the distributions involved, it incorporates prior knowledge into the models, it allows errors in the 'engineered' nodes of a system to be determined by the data, and leads to the ability to determine optimal testing strategies. In this report, we provide the preliminary steps necessary to extend this approach to systems with feedback. Feedback is an essential component of 'complexity' and provides interesting challenges in modeling the time-dependent action of a feedback loop. We provide a mechanism for doing this and analyze a simple case. We then consider some extensions to more interesting examples with local control affecting the entire system. Finally, a discussion of the status of the research is also included.

  14. Stochastic Modelling of Hydrologic Systems

    DEFF Research Database (Denmark)

    Jonsdottir, Harpa

    2007-01-01

    In this PhD project several stochastic modelling methods are studied and applied on various subjects in hydrology. The research was prepared at Informatics and Mathematical Modelling at the Technical University of Denmark. The thesis is divided into two parts. The first part contains an introduct......In this PhD project several stochastic modelling methods are studied and applied on various subjects in hydrology. The research was prepared at Informatics and Mathematical Modelling at the Technical University of Denmark. The thesis is divided into two parts. The first part contains...... an introduction and an overview of the papers published. Then an introduction to basic concepts in hydrology along with a description of hydrological data is given. Finally an introduction to stochastic modelling is given. The second part contains the research papers. In the research papers the stochastic methods...... are described, as at the time of publication these methods represent new contribution to hydrology. The second part also contains additional description of software used and a brief introduction to stiff systems. The system in one of the papers is stiff....

  15. Discrete modelling of drapery systems

    Science.gov (United States)

    Thoeni, Klaus; Giacomini, Anna

    2016-04-01

    Drapery systems are an efficient and cost-effective measure in preventing and controlling rockfall hazards on rock slopes. The simplest form consists of a row of ground anchors along the top of the slope connected to a horizontal support cable from which a wire mesh is suspended down the face of the slope. Such systems are generally referred to as simple or unsecured draperies (Badger and Duffy 2012). Variations such as secured draperies, where a pattern of ground anchors is incorporated within the field of the mesh, and hybrid systems, where the upper part of an unsecured drapery is elevated to intercept rockfalls originating upslope of the installation, are becoming more and more popular. This work presents a discrete element framework for simulation of unsecured drapery systems and its variations. The numerical model is based on the classical discrete element method (DEM) and implemented into the open-source framework YADE (Šmilauer et al., 2010). The model takes all relevant interactions between block, drapery and slope into account (Thoeni et al., 2014) and was calibrated and validated based on full-scale experiments (Giacomini et al., 2012).The block is modelled as a rigid clump made of spherical particles which allows any shape to be approximated. The drapery is represented by a set of spherical particle with remote interactions. The behaviour of the remote interactions is governed by the constitutive behaviour of the wire and generally corresponds to a piecewise linear stress-strain relation (Thoeni et al., 2013). The same concept is used to model wire ropes. The rock slope is represented by rigid triangular elements where material properties (e.g., normal coefficient of restitution, friction angle) are assigned to each triangle. The capabilities of the developed model to simulate drapery systems and estimate the residual hazard involved with such systems is shown. References Badger, T.C., Duffy, J.D. (2012) Drapery systems. In: Turner, A.K., Schuster R

  16. Identification and Radiofrequency Catheter Ablation of a Nonsustained Atrial Tachycardia at the Septal Mitral Annulus with the Use of a Noncontact Mapping System: A Case Report

    Directory of Open Access Journals (Sweden)

    Sumito Narita, MD

    2008-01-01

    Full Text Available Here we report a case of a 16-year old female with symptomatic nonsustained atrial tachycardia (NSAT originating from the septal mitral annulus. NSAT was induced by atrial burst pacing after an intravenous isoproterenol (ISP injection. The array mode of the noncontact mapping system (NCM allowed us to quickly identify the tachycardia focus at the septal mitral annulus, where the contact bipolar voltage map revealed no low voltage area (<0.5 mV. The NSAT was eliminated by a radiofrequency energy application to the identified tachycardia focus during sinus rhythm, and the patient has been free from any symptoms during 10 months of follow-up.

  17. Percutaneous central venous catheters versus peripheral cannulae for delivery of parenteral nutrition in neonates.

    Science.gov (United States)

    Ainsworth, S B; Clerihew, L; McGuire, W

    2007-07-18

    Parenteral nutrition for neonates may be delivered via a short peripheral cannula or a central venous catheter. The latter may either be inserted via the umbilicus or percutaneously. Because of the complications associated with umbilical venous catheter use, many neonatal units prefer to use percutaneously inserted catheters following the initial stabilisation period. The method of parenteral nutrition delivery may affect nutrient input and consequently growth and development. Although potentially more difficult to place, percutaneous central venous catheters may be more stable than peripheral cannulae, and need less frequent replacement. These delivery methods may also be associated with different risks of adverse events, including acquired systemic infection and extravasation injury. To determine the effect of infusion via a percutaneous central venous catheter versus a peripheral cannula on nutrient input, growth and development, and complications including systemic infection, or extravasation injuries in newborn infants who require parenteral nutrition. The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2007), MEDLINE (1966 - February 2007), EMBASE (1980 - February 2007), conference proceedings, and previous reviews. Randomised controlled trials that compared the effect of delivering parenteral nutrition via a percutaneous central venous catheter versus a peripheral cannulae in neonates. Data were extracted the data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author, and synthesis of data using relative risk, risk difference and mean difference. Four trials eligible for inclusion were found. These trials recruited a total of 368 infants and reported a number of different outcomes. One study showed that the use of a percutaneous

  18. WE-G-17A-05: Real-Time Catheter Localization Using An Active MR Tracker for Interstitial Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W; Damato, A; Viswanathan, A; Cormack, R [Dana Farber Cancer Institute / Brigham and Women' s Hospital, Boston, MA (United States); Harvard Medical School, Boston, MA (United States); Penzkofer, T; Schmidt, E [Brigham and Women' s Hospital, Boston, MA (United States); Pan, L; Gilson, W [Siemens Corporation, Corporate Technology, Baltimore, MD (United States); Seethamraju, R [Siemens Healthcare, Boston, MA (United States)

    2014-06-15

    Purpose: To develop a novel active MR-tracking system which can provide accurate and rapid localization of brachytherapy catheters, and assess its reliability and spatial accuracy in comparison to standard catheter digitization using MR images. Methods: An active MR tracker for brachytherapy was constructed by adding three printed-circuit micro-coils to the shaft of a commercial metallic stylet. A gel phantom with an embedded framework was built, into which fifteen 14-Gauge catheters were placed, following either with parallel or crossed paths. The tracker was inserted sequentially into each catheter, with MR-tracking running continuously. Tracking was also performed during the tracker's removal from each catheter. Catheter trajectories measured from the insertion and the removal procedures using the same micro-coil were compared, as well as trajectories obtained using different micro-coils. A 3D high-resolution MR image dataset of the phantom was acquired and imported into a treatment planning system (TPS) for catheter digitization. A comparison between MR-tracked positions and positions digitized from MR images by TPS was performed. Results: The MR tracking shows good consistency for varying catheter paths and for all micro-coils (mean difference ∼1.1 mm). The average distance between the MR-tracking trajectory and catheter digitization from the MR images was 1.1 mm. Ambiguity in catheter assignment from images due to crossed paths was resolved by active tracking. When tracking was interleaved with imaging, real-time images were continuously acquired at the instantaneous tip positions and displayed on an external workstation. Conclusion: The active MR tracker may be used to provide an independent measurement of catheter location in the MR environment, potentially eliminating the need for subsequent CT. It may also be used to control realtime imaging of catheter placement. This will enable MR-based brachytherapy planning of interstitial implants without

  19. CHLORHEXIDINE-IMPREGNATED DRESSING FOR PREVENTION OF CATHETER-RELATED BLOODSTREAM INFECTION: A META-ANALYSIS

    Science.gov (United States)

    Safdar, Nasia; O’Horo, John C.; Ghufran, Aiman; Bearden, Allison; Didier, Maria Eugenia; Chateau, Dan; Maki, Dennis G.

    2014-01-01

    Background Catheter related bloodstream infections (CRBSI) are associated with significant morbidity and mortality and effective methods for their prevention are needed. Objective To assess the efficacy of a chlorhexidine-impregnated dressing for prevention of central venous catheter-related colonization and CRBSI using meta-analysis. Data Sources Multiple computerized database searches supplemented by manual searches including relevant conference proceedings. Study Selection Randomized controlled trials (RCT) evaluating the efficacy of a chlorhexidine-impregnated dressing compared with conventional dressings for prevention of catheter colonization and CRBSI. Data Extraction Data were extracted on patient and catheter characteristics and outcomes. Data Synthesis Pooled estimates of the relative risk (RR) and 95% confidence intervals (CI) were obtained using the DerSimonian and Laird random effects model and the Mantel-Haenszel fixed effects model. Heterogeneity was assessed using the Cochran Q statistic and I2. Subgroup analyses were used to explore heterogeneity. Results Nine RCTs met the inclusion criteria. Use of a chlorhexidine-impregnated dressing resulted in a reduced incidence of CRBSI (random effects RR 0.57, 95% CI 0.42–0.79, P=0.002). The incidence of catheter colonization was also markedly reduced in the chlorhexidine-impregnated dressing group (random effects RR 0.51, 95% CI 0.39–0.67, Pchlorhexidine-impregnated dressing is beneficial in preventing catheter colonization and, more importantly, CRBSI and warrants routine use in patients at high risk of CRBSI and CVC or arterial catheter colonization in ICUs. PMID:24674924

  20. A cost-effectiveness analysis of long-term intermittent catheterisation with hydrophilic and uncoated catheters

    DEFF Research Database (Denmark)

    Clark, J F; Mealing, S J; Scott, D A

    2016-01-01

    -old SCI patient with chronic urinary retention will live an additional 1.4 years if using HC catheters compared with UC catheters, at an incremental cost of £2100. Moreover, the lifetime number of UTI events will be reduced by 16%. All best- and worst-case estimates were within the UK threshold of being......STUDY DESIGN: Cost-effectiveness analysisObjective:To establish a model to investigate the cost effectiveness for people with spinal cord injury (SCI), from a lifetime perspective, for the usage of two different single-use catheter designs: hydrophilic-coated (HC) and uncoated (UC). The model...... includes the long-term sequelae of impaired renal function and urinary tract infection (UTI). SETTING: Analysis based on a UK perspective. METHODS: A probabilistic Markov decision model was constructed, to compare lifetime costs and quality-adjusted life years, taking renal and UTI health states...

  1. Computational models of complex systems

    CERN Document Server

    Dabbaghian, Vahid

    2014-01-01

    Computational and mathematical models provide us with the opportunities to investigate the complexities of real world problems. They allow us to apply our best analytical methods to define problems in a clearly mathematical manner and exhaustively test our solutions before committing expensive resources. This is made possible by assuming parameter(s) in a bounded environment, allowing for controllable experimentation, not always possible in live scenarios. For example, simulation of computational models allows the testing of theories in a manner that is both fundamentally deductive and experimental in nature. The main ingredients for such research ideas come from multiple disciplines and the importance of interdisciplinary research is well recognized by the scientific community. This book provides a window to the novel endeavours of the research communities to present their works by highlighting the value of computational modelling as a research tool when investigating complex systems. We hope that the reader...

  2. Model reduction of parametrized systems

    CERN Document Server

    Ohlberger, Mario; Patera, Anthony; Rozza, Gianluigi; Urban, Karsten

    2017-01-01

    The special volume offers a global guide to new concepts and approaches concerning the following topics: reduced basis methods, proper orthogonal decomposition, proper generalized decomposition, approximation theory related to model reduction, learning theory and compressed sensing, stochastic and high-dimensional problems, system-theoretic methods, nonlinear model reduction, reduction of coupled problems/multiphysics, optimization and optimal control, state estimation and control, reduced order models and domain decomposition methods, Krylov-subspace and interpolatory methods, and applications to real industrial and complex problems. The book represents the state of the art in the development of reduced order methods. It contains contributions from internationally respected experts, guaranteeing a wide range of expertise and topics. Further, it reflects an important effor t, carried out over the last 12 years, to build a growing research community in this field. Though not a textbook, some of the chapters ca...

  3. Modeling software systems by domains

    Science.gov (United States)

    Dippolito, Richard; Lee, Kenneth

    1992-01-01

    The Software Architectures Engineering (SAE) Project at the Software Engineering Institute (SEI) has developed engineering modeling techniques that both reduce the complexity of software for domain-specific computer systems and result in systems that are easier to build and maintain. These techniques allow maximum freedom for system developers to apply their domain expertise to software. We have applied these techniques to several types of applications, including training simulators operating in real time, engineering simulators operating in non-real time, and real-time embedded computer systems. Our modeling techniques result in software that mirrors both the complexity of the application and the domain knowledge requirements. We submit that the proper measure of software complexity reflects neither the number of software component units nor the code count, but the locus of and amount of domain knowledge. As a result of using these techniques, domain knowledge is isolated by fields of engineering expertise and removed from the concern of the software engineer. In this paper, we will describe kinds of domain expertise, describe engineering by domains, and provide relevant examples of software developed for simulator applications using the techniques.

  4. [The role of the uretral catheter in the development of catheter- related urinary tract infection].

    Science.gov (United States)

    Vasilyev, A O; Govorov, A V; Shiryaev, A A; Pushkar, D Yu

    2017-12-01

    The most common source of nosocomial infection is the urinary tract, especially if they it is drained with a urethral catheter. Catheter-associated urinary tract infections account for at least 80% of all complicated urinary tract infections and are the most common type of hospital-acquired infection. Intestinal microflora plays the leading role in the pathogenesis of catheter-associated urinary tract infections, whereas the most important risk factor for their development is the long duration of urinary catheter drainage. In the case of short-term and intermittent catheterization, routine antibiotic prophylaxis is not required, but if a patient develops clinically significant infection, antibiotic therapy is required followed by definitive therapy based on culture. Urethral catheters coated with antimicrobial substances and anti-inflammatory agents can significantly reduce the adhesion and migration of bacteria, thereby reducing the incidence of urinary tract infections. Despite this, the incidence of catheter-associated infection remains high. We have reviewed recent literature related to catheter-associated urinary tract infections and the best means of preventing this condition.

  5. Mechanical dysfunction of ventriculoperitoneal shunts caused by calcification of the silicone rubber catheter.

    Science.gov (United States)

    Boch, A L; Hermelin, E; Sainte-Rose, C; Sgouros, S

    1998-06-01

    The authors studied new and calcified shunt catheters to identify the prevalence of failures caused by aging materials in the shunt. Complications associated with these devices have various origins. Among late complications, fracture or migration of the system is related to the subcutaneous adhesion of the distal tubing in a growing child. A review of a cohort of 64 children who underwent shunt placement in 1980 with barium-impregnated distal catheters showed that 10 of these patients underwent reoperation for complications related to aging of the shunt material. This group represents 15% of the whole series and 30% of those children who were followed for more than 3 years. The true impact of aging of materials on shunt function is probably underestimated. The authors performed physical, chemical, and mechanical analyses of the retrieved aged catheters and also of new catheters, resulting in the following findings: 1) calcifications were observed only on the external surface of the catheter, predominantly in its subcutaneous segment at the level of the neck and anterior chest wall; 2) calcifications contained particles of free silicon and barium sulfate, signifying fragmentation of the polymer; 3) the microstructure of the silicone polymer was modified: microfractures and alteration of the polymeric network were observed; 4) silanol groups were observed on the external surface of the catheter; and 5) the mechanical properties of the silicone rubber were degraded, and the aged catheters were more brittle than the new ones, with ruptures at elongations and fracture energy much lower than that seen in new catheters. Furthermore, in vitro testing with a metastable solution of simulated body fluid demonstrated the critical impact of pH variations in liquid media and surface degradation of the catheters on the precipitation of hydroxylapatite crystals. Although most shunt complications can be addressed by better patient management and surgical technique, late

  6. Treatment delivery platform for conformal catheter-based ultrasound hyperthermia

    Science.gov (United States)

    Juang, Titania; Wootton, Jeffery; Hsu, I.-Chow; Diederich, Chris

    2009-02-01

    A clinical treatment delivery platform has been developed for providing 3D controlled hyperthermia with catheter-based ultrasound applicators in conjunction with high dose rate (HDR) brachytherapy. This integrated system consists of hardware and software components required for thermal therapy delivery, treatment monitoring and control, and realtime and post-treatment analysis; and interstitial and endocavity ultrasound heating applicators. Hardware includes a 32-channel RF amplifier with independent power (0-25 W) and frequency (5-10 MHz) control for ultrasound power delivery and a 48-channel thermometry system compatible with 0.4 mm OD multi-sensor thermocouple probes. Software graphical user interfaces (GUI) are used to monitor and control both the amplifier and the thermometry system. The amplifier GUI controls, monitors, and records individual channel frequency and power values in real-time; the thermometry GUI monitors and records temperature and thermal dose values in real-time, as well as displaying and allowing dynamic control for temperature and thermal dose target thresholds. The thermometry GUI also incorporates registration of thermocouple positions relative to target anatomy and applicator transducers based on HDR planning tools (CT/MRI/US overlays) for improved treatment control and documentation. The interstitial (2.4 mm) and endocavity (6 mm) ultrasound hyperthermia applicators are composed of linear arrays of 1-4 tubular piezoceramic transducers - sectored at 90°, 180°, 270°, and 360° for single or dual directional heating patterns - that are compatible with plastic implant catheters. QA techniques specific to these catheter-based ultrasound applicators have been devised and implemented, and include rotational beam plots and dynamic force balance efficiency measurements, which are critical to establish applicator performance. A quality assurance test matrix has been devised and used to evaluate and characterize all components of this system

  7. Innovation in catheter design for intra-arterial liver cancer treatments results in favorable particle-fluid dynamics.

    Science.gov (United States)

    van den Hoven, Andor F; Lam, Marnix G E H; Jernigan, Shaphan; van den Bosch, Maurice A A J; Buckner, Gregory D

    2015-08-01

    Liver tumors are increasingly treated with radioembolization. Here, we present first evidence of catheter design effect on particle-fluid dynamics and downstream branch targeting during microsphere administrations. A total of 7 experiments were performed in a bench-top model of the hepatic arterial vasculature with recreated hemodynamics. Fluorescent microspheres and clinically used holmium microspheres were administered with a standard microcatheter (SMC) and an anti-reflux catheter (ARC) positioned at the same level along the longitudinal vessel axis. Catheter-related particle flow dynamics were analyzed by reviewing video recordings of UV-light illuminated fluorescent microsphere administrations. Downstream branch distribution was analyzed by quantification of collected microspheres in separate filters for two first-order branches. Mean deviation from a perfectly homogenous distribution (DHD) was used to compare the distribution homogeneity between catheter types. The SMC administrations demonstrated a random off-centered catheter position (in 71 % of experiments), and a laminar particle flow pattern with an inhomogeneous downstream branch distribution, dependent on catheter position and injection force. The ARC administrations demonstrated a fixed centro-luminal catheter position, and a turbulent particle flow pattern with a more consistent and homogenous downstream branch distribution. Quantitative analyses confirmed a significantly more homogeneous distribution with the ARC; the mean DHD was 40.85 % (IQR 22.76 %) for the SMC and 15.54 % (IQR 6.46 %) for the ARC (p = 0.047). Catheter type has a significant impact on microsphere administrations in an in-vitro hepatic arterial model. A within-patient randomized controlled trial has been initiated to investigate clinical catheter-related effects during radioembolization treatment.

  8. Vascular access in neonatology: peripherally inserted central catheter and peripheral venous catheter

    Directory of Open Access Journals (Sweden)

    Marcia Lienemann

    2014-04-01

    The objective of this paper is to present aspects of peripherally inserted central catheter and peripheral venous catheter, highlighting important points in choosing the type of access. For the passage of peripherally inserted central catheter is previously performing specific course necessary, while the primary indication occurs when it is necessary to access the patient's stay for a long period of time. Whereas peripheral venipuncture is the most appropriate in cases of needing an IV line quickly and safely, for the administration of fluids, blood collection, blood transfusion and other.

  9. Urinary catheterization diary – A useful tool in tracking causes of non-deflating Foley catheter

    Directory of Open Access Journals (Sweden)

    C.O. Okorie

    2015-06-01

    Conclusions: Most urinary catheters marketed in developing countries are unidentifiable after unpacking. A catheterization diary is a useful tool for solving catheter-related problems, and its application in health-care facilities should be encouraged. Companies marketing Foley catheters should print the catheter name on both the catheter packaging and on the catheter itself.

  10. Magnetic resonance imaging guided transatrial electrophysiological studies in swine using active catheter tracking - experience with 14 cases

    Energy Technology Data Exchange (ETDEWEB)

    Grothoff, Matthias; Gutberlet, Matthias [University of Leipzig - Heart Center, Department of Radiology, Leipzig (Germany); Hindricks, Gerhard; Sommer, Philipp; Hilbert, Sebastian [University of Leipzig - Heart Center, Department of Electrophysiology, Leipzig (Germany); Fleiter, Christian [Helios Klinikum Berlin-Buch, Department of Orthopaedic Surgery, Berlin (Germany); Schnackenburg, Bernhard [Philips Healthcare, Hamburg (Germany); Weiss, Steffen; Krueger, Sascha [Philips Innovative Technologies, Hamburg (Germany); Piorkowski, Christopher; Gaspar, Thomas [University of Dresden - Heart Center, Department of Electrophysiology, Dresden (Germany); Wedan, Steve; Lloyd, Thomas [Imricor Medical Systems, Burnsville, MN (United States)

    2017-05-15

    To evaluate the feasibility of performing comprehensive Cardiac Magnetic resonance (CMR) guided electrophysiological (EP) interventions in a porcine model encompassing left atrial access. After introduction of two femoral sheaths 14 swine (41 ± 3.6 kg) were transferred to a 1.5 T MR scanner. A three-dimensional whole-heart sequence was acquired followed by segmentation and the visualization of all heart chambers using an image-guidance platform. Two MR conditional catheters were inserted. The interventional protocol consisted of intubation of the coronary sinus, activation mapping, transseptal left atrial access (n = 4), generation of ablation lesions and eventually ablation of the atrioventricular (AV) node. For visualization of the catheter tip active tracking was used. Catheter positions were confirmed by passive real-time imaging. Total procedure time was 169 ± 51 minutes. The protocol could be completed in 12 swine. Two swine died from AV-ablation induced ventricular fibrillation. Catheters could be visualized and navigated under active tracking almost exclusively. The position of the catheter tips as visualized by active tracking could reliably be confirmed with passive catheter imaging. Comprehensive CMR-guided EP interventions including left atrial access are feasible in swine using active catheter tracking. (orig.)

  11. Impact of catheter insertion using the radial approach on vasodilatation in humans.

    Science.gov (United States)

    Dawson, Ellen A; Rathore, Sudhir; Cable, N Timothy; Wright, D Jay; Morris, John L; Green, Daniel J

    2010-02-23

    The aim of this study was to determine the impact of catheter sheath insertion, a model of endothelium disruption in humans, on the conventional FMD (flow-mediated dilatation) response in vivo. Seventeen subjects undergoing transradial catheterization were recruited and assessed prior to, the day after, and 3-4 months postcatheterization. The catheter sheath's external diameter was 2.7 mm, and the average preprocedure internal radial artery diameter was 2.8 mm, indicating a high likelihood of endothelial denudation as a consequence of sheath placement. Radial artery flow-mediated and endothelium-derived NO (nitric oxide)-dependent function (FMD) was assessed within the region of sheath placement (sheath site) and also above the sheath (catheter site). GTN (glyceryl trinitrate) endothelium-independent NO-mediated function was also assessed distally. Measurements were made in both arms at all time points; the non-catheterized arm provided an internal control. Neither sheath (4.5+/-0.9%) nor catheter (4.4+/-0.9%) insertion abolished FMD, although both significantly decreased FMD from preintervention levels (9.0+/-0.8% sheath segment; 8.4+/-0.8% catheter segment; P<0.05). The impact of sheath and catheter placement on FMD was no longer evident after approximately 3 months recovery (8.0+/-1.5 and 8.1+/-1.7%, sheath and catheter, respectively). GTN responses also decreased from 14.8+/-1.7 to 7.9+/-1.0% (P<0.05) as a result of sheath placement, but values returned to baseline at approximately 3 months (13.0+/-1.8%). These results suggest that the presence of an intact, functional endothelial layer and consequent NO release may not be obligatory for some component of the FMD response. This raises the possibility of an endothelium-independent contribution to the flow-induced vasodilatation in humans.

  12. Fibrin Sheath Angioplasty: A Technique to Prevent Superior Vena Cava Stenosis Secondary to Dialysis Catheters

    Science.gov (United States)

    Hacker, Robert I.; Garcia, Lorena De Marco; Chawla, Ankur; Panetta, Thomas F.

    2012-01-01

    Fibrin sheaths are a heterogeneous matrix of cells and debris that form around catheters and are a known cause of central venous stenosis and catheter failure. A total of 50 cases of central venous catheter fibrin sheath angioplasty (FSA) after catheter removal or exchange are presented. A retrospective review of an outpatient office database identified 70 eligible patients over a 19-month period. After informed consent was obtained, the dialysis catheter exiting the skin was clamped, amputated, and a wire was inserted. The catheter was then removed and a 9-French sheath was inserted into the superior vena cava, a venogram was performed. If a fibrin sheath was present, angioplasty was performed using an 8 × 4 or 10 × 4 balloon along the entire length of the fibrin sheath. A completion venogram was performed to document obliteration of the sheath. During the study, 50 patients were diagnosed with a fibrin sheath, and 43 had no pre-existing central venous stenosis. After FSA, 39 of the 43 patient's (91%) central systems remained patent without the need for subsequent interventions; 3 patients (7%) developed subclavian stenoses requiring repeat angioplasty and stenting; 1 patent (2.3%) developed an occlusion requiring a reintervention. Seven patients with prior central stenosis required multiple angioplasties; five required stenting of their central lesions. Every patient had follow-up fistulograms to document long-term patency. We propose that FSA is a prudent and safe procedure that may help reduce the risk of central venous stenosis from fibrin sheaths due to central venous catheters. PMID:23997555

  13. Safety and effectiveness of central venous catheters usage in newborns intensive care unit

    Directory of Open Access Journals (Sweden)

    І. А. Anikin

    2016-10-01

    Full Text Available To date, ensuring long-term venous access in newborns is an actual problem of intensive therapy. Central venous catheters, which implantable peripherally (PICC-line, are widely used as a medium-term vascular access in newborns in the department of intensive care. Objective - To study the incidence of complications associated with the use of central venous access in newborns intensive care department. Materials and methods. Characteristics and safety of various central venous access in newborns were studied. The study is retrospective, with a quantitative analysis of the results. The safe practice PICC-line and CVCSI accesses groups were compared, revealed complications in 361 newborns, who received complex intensive therapy in connection with diseases of the perinatal period, were analyzed. Results. Due to the fact that some babies accessed re-established catheters, the total number of observations was 395. We took the complications of catheter-related infection, taking into account the instructions of the Center for Disease Control and Prevention (theUSA. We searched the number of mechanical and infectious complications, which were associated with venous catheters. The number of catheter occlusion, against the background of infusion therapy was not significantly different in the groups, and the obstruction of the catheter by thrombus was the most frequent complication in the PICC-line group. CVCSIs revealed fairly large number of system thrombosis of the superior vena cava, and a great number of infectious complications. KAI Number of cases in the group of newborns with PICC-line was almost 4 times less than in infants with CVCSI venous access. Cases of death in patients did not associate with venous access, despite the fact that the total amount of complications in CVCSI group were significantly higher. Conclusion. The received results have showen that peripherally implanted catheters have a higher level of security and ease of installation

  14. Chronic swine instrumentation techniques utilizing the GOR-REX peritoneal catheter

    Science.gov (United States)

    Gray, C. C.; White, F. C.; Crisman, R. P.; Wisniewski, J.; McKirnan, D.

    1985-05-01

    The GORE-TEX peritoneal catheter interface is an effective skin interface device for many types of instrumentation in the swine. When properly utilized, the interface allows the development of a stable and effective biological seal which will reduce or eliminate sinus tract formation and resultant systemic infection. The interface is suitable for running any wire or catheter (up to about 2.5mm diameter) through the integument of the animal, thus increasing the possibilities for chronic instrumentation while maintaining a healthy animal. The lack of evidence of any growth phenomenon acting to extrude the interface segment, similar to that observed using other synthetic materials, and the superior biological seal which the interface develops, may allow many chronic studies which were previously not feasible. Using special catheter adapter stubs and an intermittent infusion plug, a sterile, sealed catheter system has decreased the possibilities for introducing pathogens while allowing ready access to the blood stream. Detailed descriptions of surgical implantation techniques and catheter set up and maintenance techniques are included.

  15. Design of a sensorized guiding catheter for in situ laser fenestration of endovascular stent.

    Science.gov (United States)

    Piazza, Roberta; Condino, Sara; Alberti, Aldo; Berchiolli, Raffaella Nice; Coppi, Gioachino; Gesi, Marco; Ferrari, Vincenzo; Ferrari, Mauro

    2017-12-01

    The in situ fenestration of a standard endograft is currently limited by difficulties in targeting the fenestration site under fluoroscopic control and by the lack of a safe method to perforate the graft. Evidence in the literature suggests the use of a 3 D electromagnetic navigator to accurately guide the endovascular instruments to the target and a laser to selectively perforate the graft. The aim of this work is to provide design guidelines to develop a sensorized catheter to guide the laser tool to the fenestration site and conduct preliminary testing of the feasibility of the proposed solution. Matherials and methods: Different catheter designs were delineated starting from engineering considerations, then prototypes were preliminarily tested to collect surgeon opinions and to steer the design process toward the preferred solution reported by the user. Finally, mechanical simulations were performed with CathCAD, a design software system for the development of composite tubing for endovascular catheters. Based on surgeon feedback, a 9-French steerable catheter with a stabilization system was designed. CathCAD simulations allowed us to define the construction parameters (e.g., materials and geometric constrains) for the fabrication of composite tubes with mechanical properties (flexural, axial, and torsional rigidities) compatible with target values in the literature for guiding catheters. The presented results preliminarily demonstrate the clinical reasonability and feasibility of the designed tool in terms of mechanical properties. Further mechanical tests and extensive in vitro clinical trials are required prior to animal testing.

  16. Efficacy and safety of novel multi-lumen catheter for chronic total occlusions: from preclinical study to first-in-man experience.

    Science.gov (United States)

    Mitsutake, Yoshiaki; Ebner, Adrian; Yeung, Alan C; Taber, Mark D; Davidson, Charles J; Ikeno, Fumiaki

    2015-02-15

    To report our initial animal and human experience with a new multi-lumen catheter called MultiCross™ (Roxwood Medical, Inc.) in a porcine coronary model and patients with a chronic total occlusion (CTO). Preclinical safety study was done in the coronary vasculature of a porcine model. In a clinical setting, patients with a CTO of a coronary artery (n = 5) were enrolled. After an initial unsuccessful attempt using a conventional guidewire, operators could use the MultiCross system. The primary efficacy endpoint was successful recanalization (technical success) and the primary safety endpoint was serious adverse events through 30 days post-procedure. The MultiCross catheter was used for all patients after failure of the initial attempt with a guidewire. Successful recanalization was achieved in all CTOs attempted (100%). No patients reported any adverse events at 30 days post-procedure. In this first-in-man experience, the MultiCross catheter has the potential to enhance crossing of CTOs. © 2014 Wiley Periodicals, Inc.

  17. Cognitive models embedded in system simulation models

    International Nuclear Information System (INIS)

    Siegel, A.I.; Wolf, J.J.

    1982-01-01

    If we are to discuss and consider cognitive models, we must first come to grips with two questions: (1) What is cognition; (2) What is a model. Presumably, the answers to these questions can provide a basis for defining a cognitive model. Accordingly, this paper first places these two questions into perspective. Then, cognitive models are set within the context of computer simulation models and a number of computer simulations of cognitive processes are described. Finally, pervasive issues are discussed vis-a-vis cognitive modeling in the computer simulation context

  18. Accidental Breakage of Lumbar Epidural Catheter - Case report ...

    African Journals Online (AJOL)

    Breakage of epidural catheter is a rare occurrence with only isolated reports. Though insertion of epidural catheter is generally considered a safe procedure, breakage during removal leaving a segment in the patient's back can occur. There are many factors associated with breakage of an epidural catheter, such as the ...

  19. Misplaced left internal jugular venous catheter with an exceptional ...

    African Journals Online (AJOL)

    Large numbers of central venous catheters (CVCs) are placed each year in the intensive care units and misplacement occurs frequently. Many critically ill patients require central venous catheterization for multiple and varied reasons. Internal jugular vein (IJV) catheter is one of the most frequent central venous catheters in ...

  20. 21 CFR 868.5120 - Anesthesia conduction catheter.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anesthesia conduction catheter. 868.5120 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5120 Anesthesia conduction catheter. (a) Identification. An anesthesia conduction catheter is a flexible tubular device used to inject...

  1. FAQs about Catheter-Associated Urinary Tract Infection

    Science.gov (United States)

    ... the bladder. What are the symptoms of a urinary tract infection? Some of the common symptoms of a urinary tract infection are: • Burning or ... catheter is removed. Sometimes people with catheter-associated urinary tract ... these symptoms of infection. Can catheter-associated urinary tract infections ...

  2. 21 CFR 884.6110 - Assisted reproduction catheters.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction catheters. 884.6110 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6110 Assisted reproduction catheters. (a) Identification. Assisted reproduction catheters are devices used in in...

  3. Intravascular catheter related infections in children admitted on the ...

    African Journals Online (AJOL)

    peripheral venous intravascular catheters uncoated with no antibiotic or antiseptic, was done. Social demographic characteristics, anthropometry, clinical examination including the catheter site were determined at enrollment. The children had their blood, catheter tip and hub samples taken off for culture and sensitivity as ...

  4. Catheter associated urinary tract infection: Aetiologic agents and ...

    African Journals Online (AJOL)

    The objective of this study was to identify microbial pathogens associated with bacteriuria and UTI in patients with indwelling urethral catheters and determine their susceptibility patterns to commonly used antimicrobial agents in our institution. Catheter urine and catheter tip specimens of all the patients were analyzed by ...

  5. Severe Tricuspid Valve Endocarditis Related to Tunneled Catheters ...

    African Journals Online (AJOL)

    The patient improved after catheter removal and treatment with ceftazidime, vancomycin and amikacin. Another patient who was maintained on chronic HD through a tunneled catheter in the right internal jugular vein presented with a limited infection in the sub-cutaneous tunnel of the catheter that improved after treatment ...

  6. Management of Non- Deflating Foley Suprapubic Catheters - A ...

    African Journals Online (AJOL)

    The procedure described uses a 10 ml syringe and needle passed through the lumen of the catheter to puncture the inner surface of the catheter balloon and thus deflate it. Because the catheter balloon does not burst in this procedure there is no risk of balloon fragmentation or subsequent stone formation. The technique is ...

  7. Dislodgment of Port-A-Cath Catheters in Children

    Directory of Open Access Journals (Sweden)

    Chi-Lin Ho

    2008-10-01

    Conclusion: The dislodgment rate of port-a-cath catheters in children in our series was 4.1%. Most (83% catheters were broken at the site of anastomosis to the port. All dislodged catheters could be successfully retrieved by transcatheter retrieval using a gooseneck snare.

  8. Thermodynamic modeling of complex systems

    DEFF Research Database (Denmark)

    Liang, Xiaodong

    . Contrary to earlier theories, the oil is not only present on the surface, but also in great volumes both in the water column and on the seafloor, which indicates that we do not know enough about how oil behaves in water and interacts with it. Sonar detection is one of the most important and necessary...... after an oil spill. Engineering thermodynamics could be applied in the state-of-the-art sonar products through advanced artificial technology, if the speed of sound, solubility and density of oil-seawater systems could be satisfactorily modelled. The addition of methanol or glycols into unprocessed well...... streams during subsea pipelines is necessary to inhibit gas hydrate formation, and the offshore reservoirs often mean complicated temperature and pressure conditions. Accurate description of the phase behavior and thermalphysical properties of complex systems containing petroleum fluids and polar...

  9. Studies of Catalytic Model Systems

    DEFF Research Database (Denmark)

    Holse, Christian

    of the Cu/ZnO nanoparticles is highly relevant to industrial methanol synthesis for which the direct interaction of Cu and ZnO nanocrystals synergistically boost the catalytic activity. The dynamical behavior of the nanoparticles under reducing and oxidizing environments were studied by means of ex situ X...... as the nanoparticles are reduced. The Cu/ZnO nanoparticles are tested on a  µ-reactor platform and prove to be active towards methanol synthesis, making it an excellent model system for further investigations into activity depended morphology changes....

  10. Adaptation of the CVT algorithm for catheter optimization in high dose rate brachytherapy

    International Nuclear Information System (INIS)

    Poulin, Eric; Fekete, Charles-Antoine Collins; Beaulieu, Luc; Létourneau, Mélanie; Fenster, Aaron; Pouliot, Jean

    2013-01-01

    computation time decrease with the number of points and that no effects were observed on the dosimetric indices when varying the number of sampling points and the number of iterations, they were respectively fixed to 2500 and to 100. The computation time to obtain ten complete treatments plans ranging from 9 to 18 catheters, with the corresponding dosimetric indices, was 90 s. However, 93% of the computation time is used by a research version of IPSA. For the breast, on average, the Radiation Therapy Oncology Group recommendations would be satisfied down to 12 catheters. Plans with nine or less catheters would not be clinically acceptable in terms of V100, dose homogeneity index, and D90.Conclusions: The authors have devised a simple, fast and efficient method to optimize the number and position of catheters in interstitial HDR brachytherapy. The method was shown to be robust for both prostate and breast HDR brachytherapy. More importantly, the computation time of the algorithm is acceptable for clinical use. Ultimately, this catheter optimization algorithm could be coupled with a 3D ultrasound system to allow real-time guidance and planning in HDR brachytherapy

  11. Adaptation of the CVT algorithm for catheter optimization in high dose rate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Fekete, Charles-Antoine Collins; Beaulieu, Luc [Département de Physique, de Génie Physique et d’Optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio-Oncologie et Axe oncologie du Centre de Recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Létourneau, Mélanie [Département de Radio-Oncologie, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Fenster, Aaron [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (United Kingdom); Pouliot, Jean [Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, 1600 Divisadero Street, San Francisco, California 94143-1708 (United States)

    2013-11-15

    computation time decrease with the number of points and that no effects were observed on the dosimetric indices when varying the number of sampling points and the number of iterations, they were respectively fixed to 2500 and to 100. The computation time to obtain ten complete treatments plans ranging from 9 to 18 catheters, with the corresponding dosimetric indices, was 90 s. However, 93% of the computation time is used by a research version of IPSA. For the breast, on average, the Radiation Therapy Oncology Group recommendations would be satisfied down to 12 catheters. Plans with nine or less catheters would not be clinically acceptable in terms of V100, dose homogeneity index, and D90.Conclusions: The authors have devised a simple, fast and efficient method to optimize the number and position of catheters in interstitial HDR brachytherapy. The method was shown to be robust for both prostate and breast HDR brachytherapy. More importantly, the computation time of the algorithm is acceptable for clinical use. Ultimately, this catheter optimization algorithm could be coupled with a 3D ultrasound system to allow real-time guidance and planning in HDR brachytherapy.

  12. Catheter Removal versus Retention in the Management of Catheter-Associated Enterococcal Bloodstream Infections

    Directory of Open Access Journals (Sweden)

    Jonas Marschall

    2013-01-01

    Full Text Available BACKGROUND: Enterococci are an important cause of central venous catheter (CVC-associated bloodstream infections (CA-BSI. It is unclear whether CVC removal is necessary to successfully manage enterococcal CA-BSI.

  13. Twisting method for reducing friction during insertion of a sheath introducer and a sheathless guiding catheter.

    Science.gov (United States)

    Takagawa, Yoshitoki; Furukawa, Tetsuaki

    2018-01-01

    A sheathless system that inserts a catheter directly into the artery can reduce puncture site-related complications through a 2-Fr reduction of the outer diameter. However, the gap between the dilator and the guiding catheter of the sheathless system is larger than the gap between the dilator and sheath of the introducer system, resulting in stronger insertion resistance. A twisting method with rapid alternating rotation of a device to the left and right during insertion can reduce the insertion resistance. This method can be effective with the sheathless system which has a larger gap. To examine the effect of size reduction on the sheathless system and the effect of insertion resistance reduction using the twisting method, we developed an insertion simulator and compared insertion resistance to a 5-Fr sheath introducer and a 5-Fr sheathless system, with and without the twisting method. The insertion simulator pushed a sheath introducer or a sheathless system toward a mock artery consisted with a 5-mm urethane and a 1-mm rubber sheet by an electrical motor with or without twisting motion generated by a crank shaft. Insertion resistance during the penetration was measured by a tension meter. The insertion resistance was less with the 5-Fr sheathless system than with the 5-Fr sheath introducer. The resistance reduced further with use of twisting for both the sheathed and sheathless catheters. In conclusion, the experiment suggests the benefits of twisting insertion of a sheathless guiding catheter for reduction of puncture site-related complications.

  14. The catheter to vein ratio and rates of symptomatic venous thromboembolism in patients with a peripherally inserted central catheter (PICC): a prospective cohort study.

    Science.gov (United States)

    Sharp, Rebecca; Cummings, Melita; Fielder, Andrea; Mikocka-Walus, Antonina; Grech, Carol; Esterman, Adrian

    2015-03-01

    Peripherally inserted central catheters (PICCs) are a common vascular access device used in clinical practice. Their use may be complicated by adverse events such as venous thromboembolism (VTE). The size of the vein used for PICC insertion and thus the catheter to vein ratio is thought to be a controllable factor in the reduction of VTE rates in patients who have a PICC. However, an optimal catheter to vein ratio for PICC insertion has not previously been investigated to inform clinical practice. To determine the effect of the catheter to vein ratio (proportion of the vein measured at the insertion point taken up by the catheter) on rates of symptomatic VTE in patients with a PICC and identify the optimal ratio cut-off point to reduce rates of this adverse event. Adult patients waiting for PICC insertion at a large metropolitan teaching hospital were recruited between May and December 2013. Vein diameter at the PICC insertion site was measured using ultrasound with in-built callipers. Participants were followed up at eight weeks to determine if they developed symptomatic VTE. Data were available for 136 patients (50% cancer; 44% infection; 6% other indication for PICC). Mean age was 57 years with 54% males. There were four cases of confirmed symptomatic VTE (two involving the deep veins, one peripheral vein and one pulmonary embolism). Receiver operator characteristic (ROC) analysis determined that a 45% catheter to vein ratio was the ideal cut off point to maximise sensitivity and specificity (AUC 0.761; 95% CI 0.681-0.830). When a ratio of 46% or above was compared to one that was less than or equal to 45% using a log binomial generalised linear model it was found that participants with a catheter to vein ratio >45% were 13 times more likely to suffer VTE (relative risk 13, p=0.022; CI 1.445-122.788). It was found that a 45% catheter to vein ratio was the optimal cut off with high sensitivity and specificity to reduce the risk of VTE. However, further research

  15. Reservoir Model Information System: REMIS

    Science.gov (United States)

    Lee, Sang Yun; Lee, Kwang-Wu; Rhee, Taehyun; Neumann, Ulrich

    2009-01-01

    We describe a novel data visualization framework named Reservoir Model Information System (REMIS) for the display of complex and multi-dimensional data sets in oil reservoirs. It is aimed at facilitating visual exploration and analysis of data sets as well as user collaboration in an easier way. Our framework consists of two main modules: the data access point module and the data visualization module. For the data access point module, the Phrase-Driven Grammar System (PDGS) is adopted for helping users facilitate the visualization of data. It integrates data source applications and external visualization tools and allows users to formulate data query and visualization descriptions by selecting graphical icons in a menu or on a map with step-by-step visual guidance. For the data visualization module, we implemented our first prototype of an interactive volume viewer named REMVR to classify and to visualize geo-spatial specific data sets. By combining PDGS and REMVR, REMIS assists users better in describing visualizations and exploring data so that they can easily find desired data and explore interesting or meaningful relationships including trends and exceptions in oil reservoir model data.

  16. Intravascular Cooling Catheter-Related Venous Thromboembolism After Hypothermia: A Case Report and Review of the Literature.

    Science.gov (United States)

    Wang, Xuan; Moy, Brian T; Hiendlmayr, Brett J; Krainski, Felix; Duvall, W Lane; Fernandez, Antonio B

    2018-03-23

    Fifty-four year-old man with recent history of myocardial infarction and a percutaneous coronary intervention who suffered a ventricular fibrillation arrest at home. He was resuscitated in the field. His heart rhythm was in atrial fibrillation. The cardiac catheterization showed a patent stent from his previous myocardial infarction and no new occlusions. He subsequently underwent hypothermia protocol using the Alsius CoolGard 3000 Temperature Control System and Icy Catheter. Heparin drip was started for atrial fibrillation 36 hours after catheter insertion and became therapeutic 2 hours before the end of cooling maintenance phase. Heparin drip was stopped 4 hours into the rewarming phase because of spontaneous conversion to sinus rhythm. Subcutaneous heparin was resumed for deep venous thrombosis prophylaxis. He was extubated to room air after hypothermia protocol. The cooling catheter was removed 88 hours after insertion. Within 1 minute of catheter removal, his oxygen saturation dropped to 80%. Transthoracic echocardiogram showed a mobile thrombus in the right atrium prolapsing into the right ventricle. Computer tomography angiography of the chest confirmed a large saddle embolus. Ninety minutes later, patient went into cardiac arrest with pulseless electrical activity while he was being considered for surgical embolectomy, but he could not be resuscitated. The temporal relationship of the catheter removal and his acute clinical decompensation led to believe that this was an intravascular cooling catheter (ICC)-related event. Providers should be cognizant of the complications of central venous catheters such as thrombosis formation, as it could lead to fatal pulmonary embolism. Physicians should promote frequent assessment of the access site(s) during routine physical examinations and potentially use point of care vascular ultrasound in high-risk cases to rule out a catheter-associated thrombus before catheter removal.

  17. electrode catheter techniques for treattnent of supraventricular ...

    African Journals Online (AJOL)

    damaged by radiofrequency energy (RP) delivered via catheters insened percutaneously without general anaes- thesia. The technique and results of its use were the main topics of interest at the 9th World Symposium on. Cardiac Pacing and Electrophysiology held in. Washington, DC, in June 1991. Effective cure of WPW.

  18. Percutaneous Placement of Peritoneal Dialysis Catheters in ...

    African Journals Online (AJOL)

    Background: The percutaneous placement of peritoneal dialysis (PD) catheters using conscious sedation with ultrasound and fluoroscopic guidance is underutilised and hasseveral advantages over the open surgical and laparoscopic placement methods, especially in the resource-limited developing world. Objectives: To ...

  19. OCCASIONAL REVIEW 'Map and zap' - electrode catheter ...

    African Journals Online (AJOL)

    Where does this leave surgical treatment of WPW syndrome? Despite the high success rates reported, ·it is acknowledged that not all patients can be successfully treated by catheter ablation. The treatment of those with multiple accessory pathways and associated defects such as Ebstein's anomaly of the tricuspid valve is ...

  20. Ultraminiature manometer-tipped cardiac catheter

    Science.gov (United States)

    Coon, G. W.

    1967-01-01

    Miniature diaphragm-type capacitance transducer capable of being mounted on the end of a cardiac catheter has been developed for measurement of intravascular pressures. The transducer can be inserted in small ducts /arteries and veins/ without disturbing the flow characteristics. It is very useful for making measurements in babies.

  1. Modeling learning technology systems as business systems

    NARCIS (Netherlands)

    Avgeriou, Paris; Retalis, Symeon; Papaspyrou, Nikolaos

    2003-01-01

    The design of Learning Technology Systems, and the Software Systems that support them, is largely conducted on an intuitive, ad hoc basis, thus resulting in inefficient systems that defectively support the learning process. There is now justifiable, increasing effort in formalizing the engineering

  2. Concurrent use of pigtail and loop snare catheters for percutaneous retrieval of dislodged central venous port catheter

    Directory of Open Access Journals (Sweden)

    Ming-Tsung Chuang

    2011-11-01

    Full Text Available The purpose of this study was to report our experience of percutaneous retrieval of dislodged port catheters with concurrent use of pigtail and loop snare catheters. During a 5-year period at our institute (June 2005 to July 2010, a total of 23 dislodged port catheters were retrieved. The interval between port catheter implantation and dislodged catheter retrieval ranged from 43 days to 1,414 days (mean 586.7 days. The time of delayed retrieval ranged from 1 day to 45 days (mean 4.6 days. All dislodged catheters were retrieved with the concurrent use of pigtail and loop snare catheters via femoral venous route. The prevalence of port catheter dislodgement at our institute was 3.4%. All dislodged port catheters were removed successfully with pigtail and loop snare catheters together. No procedure-related complications were encountered, except for transient arrhythmia in two patients, which required no medication. In conclusion, the concurrent use of pigtail and loop snare catheters is a feasible and easy way for percutaneous retrieval of a dislodged central venous port catheter.

  3. Placement issues of hemodialysis catheters with pre-existing central lines and catheters.

    Science.gov (United States)

    Aurshina, Afsha; Hingorani, Anil; Alsheekh, Ahmad; Kibrik, Pavel; Marks, Natalie; Ascher, Enrico

    2018-03-01

    It has been a widely accepted practice that a previous placed pacemaker, automatic implantable cardioverter defibrillators, or central line can be a contraindication to placing a hemodialysis catheter in the ipsilateral jugular vein. Fear of dislodging pacing wires, tunneling close to the battery site or causing venous obstruction has been a concern for surgeons and interventionalists alike. We suggest that this phobia may be unfounded. A retrospective review was conducted of patients in whom hemodialysis catheters were placed over a period of 10 years. For each hemodialysis catheter that was placed, perioperative chest X-ray performed was used to evaluate for pre-existing pacemakers and central lines. The position and laterality of placement of the hemodialysis catheter along with presence of arteriovenous fistula with functional capacity for access were noted. A total of 600 hemodialysis catheters were placed in patients over the period of 10 years. The mean age of the patients was 73.6 ± 12 years with a median age of 76 years. We found 20 pacemakers or automatic implantable cardioverter defibrillators and 19 central lines on the same side of the neck as the hemodialysis catheter that was placed in the ipsilateral jugular vein. No patient exhibited malfunction or dislodgment of the central line, the pacemaker, or automatic implantable cardioverter defibrillator or evidence of upper extremity venous obstruction based upon signs symptoms or duplex exams. Based on our experience, we suggest that placement of hemodialysis catheter in the internal jugular vein ipsilateral to the pre-existing catheter/leads is safe and spares the contralateral limb for arteriovenous fistula creation.

  4. Fibrosis in tubularized skin flaps in rats, using silicon catheters with two different degrees of flexibility: experimental model Fibrose em retalhos tubulizados de pele de ratos usando cateteres de diferentes flexibilidades como molde: modelo experimental

    Directory of Open Access Journals (Sweden)

    Antonio Henrique Rodrigues dos Passos

    2008-06-01

    Full Text Available PURPOSE: Microscopically evaluate the intensity of fibrosis in tubularized skin flaps on the back of Wistar rats, using silicon molds with different degrees of flexibility. METHODS: Twenty rats were submitted to three tubularized skin flaps on their backs. In two tubular flaps, we placed, as a mold, silicon catheters with different degrees of flexibility and removed them on the seventh day after the surgery. They were divided into two groups and euthanized, on the seventh and twenty-first days respectively after the surgery for the collection of the pieces, coloration with Masson tricromic, quantification of the area of each sample and comparison among the groups. RESULTS: Fibrosis was less intense on the tubular flaps where a catheter was not used as a mold. No significant difference was verified among the pieces with the silicon catheters, but there was a tendency of less fibrosis on the tubules with the most flexible catheter. CONCLUSION: There was no significant difference among the two catheter types. Fibrosis was less intense in the flaps where the mold was not used.OBJETIVO: Avaliar microscopicamente a intensidade da fibrose em retalhos tubulares de pele do dorso de ratos Wistar em uso de moldes de silicone de diferentes flexibilidades. MÉTODOS: Vinte animais foram submetidos à confecção de três retalhos tubulizados de pele na região dorsal. Em dois túbulos foram colocados, como molde, cateteres de silicone com flexibilidades diferentes e retirados no sétimo dia após a cirurgia. Foram divididos em dois grupos e sacrificados, respectivamente, no sétimo e vigésimo primeiro dia após a cirurgia para a coleta das peças, coloração pelo tricrômico de Masson, quantificação da área de cada amostra e comparação entre os grupos. RESULTADOS: A fibrose foi menos intensa nos retalhos tubulares em que não se usou cateter como molde. Não se verificou diferença significativa entre os retalhos com os cateteres de silicone, mas sim

  5. Bond graph modeling of centrifugal compression systems

    OpenAIRE

    Uddin, Nur; Gravdahl, Jan Tommy

    2015-01-01

    A novel approach to model unsteady fluid dynamics in a compressor network by using a bond graph is presented. The model is intended in particular for compressor control system development. First, we develop a bond graph model of a single compression system. Bond graph modeling offers a different perspective to previous work by modeling the compression system based on energy flow instead of fluid dynamics. Analyzing the bond graph model explains the energy flow during compressor surge. Two pri...

  6. Structuring Problem Analysis for Embedded Systems Modelling

    NARCIS (Netherlands)

    Marincic, J.; Mader, Angelika H.; Wieringa, Roelf J.; Lucas, Yan

    Our interest is embedded systems validation as part of the model-driven approach. To design a model, the modeller needs to obtain knowledge about the system and decide what is relevant to model and how. A part of the modelling activities is inherently informal - it cannot be formalised in such a way

  7. Urethral catheters: can we reduce use?

    Directory of Open Access Journals (Sweden)

    van den Akker-van Marle M Elske

    2011-05-01

    Full Text Available Abstract Background Indwelling urinary catheters are the main cause of healthcare-associated urinary tract infections. It can be expected that reduction of the use of urinary catheters will lead to decreased numbers of urinary tract infection. Methods The efficacy of an intervention programme to improve adherence to recommendations to reduce the use of urethral catheters was studied in a before-after comparison in ten Dutch hospitals. The programme detected barriers and facilitators and each individual facility was supported with developing their own intervention strategy. Outcome was evaluated by the prevalence of catheters, alternatives such as diapers, numbers of urinary tract infections, the percentage of correct indications and the duration of catheterization. The costs of the implementation as well as the catheterization were evaluated. Results Of a population of 16,495 hospitalized patients 3335 patients of whom 2943 were evaluable for the study, had a urethral catheter. The prevalence of urethral catheters decreased insignificantly in neurology (OR 0.93; 95% CI 0.77 - 1.13 and internal medicine wards (OR 0.97; 95% CI 0.83 - 1.13, decreased significantly in surgical wards (OR 0.84; 95% CI 0.75 - 0.96, but increased significantly in intensive care (IC and coronary care (CC units (OR 1.48; 95% CI 1.01 - 2.17. The use of alternatives was limited and remained so after the intervention. Duration of catheterization decreased insignificantly in IC/CC units (ratio after/before 0.95; 95% CI 0.78 - 1.16 and neurology (ratio 0.97; 95% CI 0.80 - 1.18 and significantly in internal medicine (ratio 0.81; 95% CI 0.69 - 0.96 and surgery wards (ratio 0.80; 95% CI 0.71 - 0.90. The percentage of correct indications on the day of inclusion increased from 50 to 67% (p Conclusion Targeted implementation of recommendations from an existing guideline can lead to better adherence and cost savings. Especially, hospitals which use a lot of urethral catheters or

  8. Resection of deep-seated gliomas using neuroimaging for stereotactic placement of guidance catheters

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Kengo; Higashi, Hisato; Tomita, Susumu; Furuta, Tomohisa; Ohmoto, Takashi [Okayama Univ. (Japan). School of Medicine

    1995-03-01

    A simple computed tomography- (CT) or magnetic resonance (MR) imaging-guided stereotactic method for guided microsurgical resection of either deep-seated gliomas or tumors adjacent to an eloquent area is described. The technique employs the Brown-Roberts-Wells stereotactic system and twist drills, 2.7 mm in diameter, for the stereotactic placement of 2.4 mm diameter scaled guidance catheters through the calvaria. In a patient with a deep-seated small glioma, less than 2 cm diameter, one catheter was implanted into the center of the enhanced mass through the cerebral cortex. In the other 14 patients, three to six catheters were used which made the tumor border clearer. After implantation of the guidance catheters, the stereotactic frame was removed and a standard open craniotomy performed. Target localization is not affected by brain movement, which is inevitable during open surgery. The tumor involved the frontal lobe in eight patients, the parietal lobe in two, and the thalamus in five. In all cases the lesion was quickly localized and radical removal was acheived. Neurological complications occurred in only one patient who suffered transient hemiparesis after the resection of a lesion in the pyramidal tract. The results demonstrate that microsurgery combined with CT- or MR imaging-guided stereotactic placement of guidance catheters is a new option for surgery of deep-seated gliomas or tumors adjacent to an eloquent area. (author).

  9. Causes and nursing countermeasures in pediatric PICC catheter complications.

    Science.gov (United States)

    Xiang, Mingli; Li, Na; Yi, Lan; Liu, Bin

    2016-01-01

    To analyze the complications and nursing countermeasures of PICC (Peripherally Inserted Central Catheter) catheters using children PICC catheter technique 40 cases, complications were observed, and analyze the original causes, in order to propose a solution. There were 10 cases of catheter blockage, 5 cases of catheter infection, 6 cases of phlebitis, 5 cases of puncture difficulties, 2 cases of poor feeding tube, 2 cases of bleeding puncture site with the continuous exploration and research of nursing intervention, the production of clinical complications from PICC has been used in children were greatly reduced.

  10. Indwelling Urinary Catheter-Related Problems After Laparoscopic Radical Prostatectomy.

    Science.gov (United States)

    Reuvers, Sarah; Zonneveld, Willemijn; Meiland-van Bakel, Marja; Putter, Hein; Nicolai, Melianthe; Pelger, Rob; Elzevier, Henk

    2016-01-01

    The purpose of this study was to determine occurrence rates of catheter-related problems and their association to pertinent clinical characteristics in men with indwelling urinary catheters following laparoscopic radical prostatectomy. Descriptive, correlational study. One hundred twelve men who underwent laparoscopic radical prostatectomy between December 2010 and December 2012 at the Leiden University Medical Centre in the Netherlands were included in this study. After surgery, a Charriere 20 (20F) silicone catheter was left indwelling for 1 week. Data were gathered from 2 sources; we reviewed participants' medical records, and participants completed a questionnaire designed for this study. Pearson χ tests were used to analyze associations between dichotomous and ordinal variables and catheter-related problems. Univariate logistic regression analyses were used to analyze the relationships between continuous factors and catheter-related problems. Seventy-five percent of participants reported at least 1 catheter-related problem. Univariate regression analyses revealed correlations between body weight and experiencing catheter-related problems (odds ratio [OR] = 1.050; P = .028) and between body mass index and experiencing catheter-related problems (OR = 1.159; P = .049). Indwelling catheter-related problems after laparoscopic radical prostatectomy are prevalent, and they may occur at any time during the entire period of catheter use. High body mass index and high body weight were associated with an increased likelihood of catheter-related problems following radical prostatectomy.

  11. Radiologically placed tunneled peritoneal catheter in palliation of malignant ascites

    Energy Technology Data Exchange (ETDEWEB)

    Akinci, Devrim; Erol, Bekir; Ciftci, Tuerkmen T. [Hacettepe University, Faculty of Medicine, Department of Radiology, 06100 Ankara (Turkey); Akhan, Okan, E-mail: akhano@tr.net [Hacettepe University, Faculty of Medicine, Department of Radiology, 06100 Ankara (Turkey)

    2011-11-15

    The purpose of this study was to evaluate retrospectively the safety and effectiveness of radiologically placed tunneled peritoneal catheter in palliation of malignant ascites. Between July 2005 and June 2009, 41 tunneled peritoneal catheters were placed under ultrasonographic and fluoroscopic guidance in 40 patients (mean age, 55 years; 22 women) who had symptomatic malignant ascites. No procedure related mortality was observed. Major complication occurred in one patient (2.5%) in the form of serious bacterial peritonitis that necessitated catheter removal. Minor complications such as minor bacterial peritonitis, catheter dislodgement, tunnel infection, and catheter blockage occurred in 11 patients (27.5%). The mean duration of survival after catheter placement was 11.8 weeks. All patients expired of their primary malignancies in the follow-up. Radiologically placed tunneled peritoneal catheter is safe and effective in palliation of symptomatic malignant ascites.

  12. A magnetic force sensor on a catheter tip for minimally invasive surgery.

    Science.gov (United States)

    Chatzipirpiridis, G; Erne, P; Ergeneman, O; Pane, S; Nelson, B J

    2015-08-01

    This paper presents a magnetically guided catheter for minimally invasive surgery (MIS) with a magnetic force sensing tip. The force sensing element utilizes a magnetic Hall sensor and a miniature permanent magnet mounted on a flexible encapsulation acting as the sensing membrane. It is capable of high sensitivity and robust force measurements suitable for in-vivo applications. A second larger magnet placed on the catheter allows the catheter to be guided by applying magnetic fields. Precise orientation control can be achieved with an external magnetic manipulation system. The proposed device can be used in many applications of minimally invasive surgery (MIS) to detect forces applied on tissue during procedures or to characterize different types of tissue for diagnosis.

  13. Modeling Power Systems as Complex Adaptive Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

    2004-12-30

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

  14. In Vivo Biocompatibility and In Vitro Efficacy of Antimicrobial Gendine-Coated Central Catheters

    Science.gov (United States)

    Jamal, Mohamed A.; Hachem, Ray Y.; Rosenblatt, Joel; McArthur, Mark J.; Felix, Edd; Jiang, Ying; Tailor, Ramesh C.

    2015-01-01

    Antimicrobial peripherally inserted central catheters (PICCs) might reduce the incidence of central line-associated bloodstream infections (CLABSI). We tested the biocompatibility of a novel gendine-coated (combination of chlorhexidine [CHX] and gentian violet [GV]) PICC in a rabbit intravascular model and tested antimicrobial efficacy in comparison with commercially available minocycline/rifampin (M/R)- and CHX-treated PICCs in an in vitro biofilm colonization model. Gendine-coated and uncoated control PICCs were inserted in the jugular veins of rabbits for 4 days. Histopathological analysis was performed at the end of the 4-day period, and circulating levels of CHX and GV in the blood were measured at different time points using liquid chromatography-mass spectrometry. The antimicrobial efficacy of the PICCs was tested following simulated intravascular indwells of 24 h and 1 week against clinical isolates of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, Candida albicans, and Candida glabrata. Rabbits implanted with gendine-coated PICCs exhibited reduced levels of thrombosis and inflammation compared to those of the rabbits with uncoated controls. No GV was detected in blood samples over the entire study period, and trace concentrations of CHX were detected. The gendine-coated PICCs completely prevented the adherence of all pathogens from 24 h to 1 week (P ≤ 0.001), while M/R-treated, CHX-treated, and control PICCs did not. Gendine-coated PICCs were highly effective in preventing biofilm formation of multidrug-resistant pathogenic bacteria and fungi. Gendine-coated PICCs were biocompatible in an intravascular setting. Further, the pharmacokinetic testing established that acute systemic exposures of CHX and GV from the gendine-coated catheters were well within safe levels. PMID:26124171

  15. Visual computing model for immune system and medical system.

    Science.gov (United States)

    Gong, Tao; Cao, Xinxue; Xiong, Qin

    2015-01-01

    Natural immune system is an intelligent self-organizing and adaptive system, which has a variety of immune cells with different types of immune mechanisms. The mutual cooperation between the immune cells shows the intelligence of this immune system, and modeling this immune system has an important significance in medical science and engineering. In order to build a comprehensible model of this immune system for better understanding with the visualization method than the traditional mathematic model, a visual computing model of this immune system was proposed and also used to design a medical system with the immune system, in this paper. Some visual simulations of the immune system were made to test the visual effect. The experimental results of the simulations show that the visual modeling approach can provide a more effective way for analyzing this immune system than only the traditional mathematic equations.

  16. Model Information Exchange System (MIXS).

    Science.gov (United States)

    2013-08-01

    Many travel demand forecast models operate at state, regional, and local levels. While they share the same physical network in overlapping geographic areas, they use different and uncoordinated modeling networks. This creates difficulties for models ...

  17. Two sustainable energy system analysis models

    DEFF Research Database (Denmark)

    Lund, Henrik; Goran Krajacic, Neven Duic; da Graca Carvalho, Maria

    2005-01-01

    This paper presents a comparative study of two energy system analysis models both designed with the purpose of analysing electricity systems with a substantial share of fluctuating renewable energy.......This paper presents a comparative study of two energy system analysis models both designed with the purpose of analysing electricity systems with a substantial share of fluctuating renewable energy....

  18. Models for multimegawatt space power systems

    Energy Technology Data Exchange (ETDEWEB)

    Edenburn, M.W.

    1990-06-01

    This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.

  19. Healthcare resource consumption for intermittent urinary catheterisation: cost-effectiveness of hydrophilic catheters and budget impact analyses.

    Science.gov (United States)

    Rognoni, Carla; Tarricone, Rosanna

    2017-01-17

    This study presents a cost-effectiveness analysis comparing hydrophilic coated to uncoated catheters for patients performing urinary intermittent catheterisation. A national budget impact analysis is also included to evaluate the impact of intermittent catheterisation for management of bladder dysfunctions over a period of 5 years. A Markov model (lifetime horizon, 1 year cycle length) was developed to project health outcomes (life years and quality-adjusted life years) and economic consequences related to patients using hydrophilic coated or uncoated catheters. The model was populated with catheter-related clinical efficacy data retrieved from randomised controlled trials and quality-of-life data (utility weights) from the literature. Cost data (EUR, 2015) were estimated on the basis of healthcare resource consumption derived from an e-survey addressed to key opinion leaders in the field. Italian Healthcare Service perspective. Patients with spinal cord injury performing intermittent urinary catheterisation in the home setting. Incremental cost-effectiveness and cost-utility ratios (ICER and ICUR) of hydrophilic coated versus uncoated catheters and associated healthcare budget impact. The base-case ICER and ICUR associated with hydrophilic coated catheters were €20 761 and €24 405, respectively. This implies that hydrophilic coated catheters are likely to be cost-effective in comparison to uncoated ones, as proposed Italian threshold values range between €25 000 and €66 400. Considering a market share at year 5 of 89% hydrophilic catheters and 11% uncoated catheters, the additional cost for Italy is approximately €12 million in the next 5 years (current market share scenario for year 0: 80% hydrophilic catheters and 20% uncoated catheters). Considered over a lifetime, hydrophilic coated catheters are potentially a cost-effective choice in comparison to uncoated ones. These findings can assist policymakers in evaluating intermittent

  20. Modeling traceability in system of systems

    NARCIS (Netherlands)

    Tekinerdogan, Bedir; Erata, Ferhat

    2017-01-01

    An important aspect in SoS is the realization of the concerns in different systems that work together. Identifying and locating these concerns is important to orchestrate the overall activities and hereby to achieve the overall goal of the SoS. Moreover, concerns in SoS are rarely stable and need

  1. Modeling of Nonlinear Systems using Genetic Algorithm

    Science.gov (United States)

    Hayashi, Kayoko; Yamamoto, Toru; Kawada, Kazuo

    In this paper, a newly modeling system by using Genetic Algorithm (GA) is proposed. The GA is an evolutionary computational method that simulates the mechanisms of heredity or evolution of living things, and it is utilized in optimization and in searching for optimized solutions. Most process systems have nonlinearities, so it is necessary to anticipate exactly such systems. However, it is difficult to make a suitable model for nonlinear systems, because most nonlinear systems have a complex structure. Therefore the newly proposed method of modeling for nonlinear systems uses GA. Then, according to the newly proposed scheme, the optimal structure and parameters of the nonlinear model are automatically generated.

  2. Preventing central venous catheter-related infection in a surgical intensive-care unit

    NARCIS (Netherlands)

    Bijma, R; Girbes, AR; Kleijer, DJ; Zwaveling, JH

    The cumulative effect of five measures (introduction of hand disinfection with alcohol, a new type of dressing, a one-bag system for parenteral nutrition, a new intravenous connection device, and surveillance by an infection control practitioner) on central venous catheter colonization and

  3. Retrograde epidural catheter relieves intractable sacral pain

    Directory of Open Access Journals (Sweden)

    Ruchir Gupta

    2016-01-01

    Full Text Available Pain caused by tumor infiltration of the sacral area remains a major clinical challenge. Patients with poor pain control despite comprehensive medical management may be treated with neuraxial techniques such as continuous epidural or spinal anesthetic. We report a case in which a patient with metastatic breast cancer experienced inadequate pain relief after multiple intravenous pain management regimens as well as intrathecal (IT drug delivery. The concentration of local anesthetics delivered via the IT catheter was limited due to the patient's baseline motor weakness which would be exacerbated with higher concentrations of local anesthetics. Thus, a decision was made to insert an epidural catheter via a retrograde technique to provide the patient with a “band of anesthesia” which would provide profound sensory blockade without concomitant motor weakness. Pain refractory to other modalities of pain control was successfully treated with the epidural technique.

  4. Percutaneous catheter drainage of tuberculous psoas abscesses

    International Nuclear Information System (INIS)

    Pombo, F.; Martin-Egana, R.; Cela, A.; Diaz, J.L.; Linares-Mondejar, P.; Freire, M.

    1993-01-01

    Six patients with 7 tuberculous psoas or ilio-psoas abscesses were treated by CT-guided catheter drainage and chemotherapy. The abscesses (5 unilateral and 1 bilateral) were completely drained using a posterior or lateral approach. The abscess volume was 70 to 700 ml (mean 300 ml) and the duration of drainage 5 to 11 days (mean 7 days). Immediate local symptomatic improvement was achieved in all patients, and there were no procedural complications. CT follow-up at 3 to 9 months showed normalization in 5 patients, 2 of whom are still in medical therapy. One patient, who did not take the medication regularly, had a recurrent abscess requiring new catheter drainage after which the fluid collection disappeared. Percutaneous drainage represents an efficient and attractive alternative to surgical drainage as a supplement to medical therapy in the management of patients with large tuberculous psoas abscesses. (orig.)

  5. Urgent peritoneal dialysis or hemodialysis catheter dialysis.

    Science.gov (United States)

    Lok, Charmaine E

    2016-03-01

    Worldwide, there is a steady incident rate of patients with end-stage kidney disease (ESKD) who require renal replacement therapy. Of these patients, approximately one-third have an "unplanned" or "urgent" start to dialysis. This can be a very challenging situation where patients have either not had adequate time for education and decision making regarding dialysis modality and appropriate dialysis access, or a decision was made and plans were altered due to unforeseen circumstances. Despite such unplanned starts, clinicians must still consider the patient's ESKD "life-plan", which includes the best initial dialysis modality and access to suit the patient's individual goals and their medical, social, logistic, and facility circumstances. This paper will discuss the considerations of peritoneal dialysis and a peritoneal dialysis catheter access and hemodialysis and central venous catheter access in patients who require an urgent start to dialysis.

  6. Inappropriate urinary catheter reinsertion in hospitalized older patients.

    Science.gov (United States)

    Hu, Fang-Wen; Tsai, Chuan-Hsiu; Lin, Huey-Shyan; Chen, Ching-Huey; Chang, Chia-Ming

    2017-01-01

    We investigated the incidence and rationale for inappropriate reinsertion of urinary catheters and elucidated whether reinsertion is an independent predictor of adverse outcomes. A longitudinal study was adopted. Patients aged ≥65 years with urinary catheters placed within 24 hours of hospitalization were enrolled. Data collection, including demographic variables and health conditions, was conducted within 48 hours after admission. Patients with catheters in place were followed-up every day. If the patient had catheter reinsertion, the reinsertion information was reviewed from medical records. Adverse outcomes were collected at discharge. A total of 321 patients were enrolled. Urinary catheters were reinserted in 66 patients (20.6%), with 95 reinsertions; 49.5% of catheter reinsertions were found to be inappropriate. "No evident reason for urinary catheter use" was the most common rationale for inappropriate reinsertion. Inappropriate reinsertion was found to be a significant predictor for prolonged length of hospital stay, development of catheter-associated urinary tract infections and catheter-related complications, and decline in activities of daily living. This study indicates a considerable percentage of inappropriate urinary catheter reinsertions in hospitalized older patients. Inappropriate reinsertion was significantly associated with worsening outcomes. Efforts to improve appropriateness of reinsertion and setting clinical policies for catheterization are necessary to reduce the high rate of inappropriate reinsertion. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  7. Peritoneal dialysis catheter embedment: surgical considerations, expectations, and complications.

    Science.gov (United States)

    Crabtree, John H; Burchette, Raoul J

    2013-10-01

    Peritoneal dialysis catheter embedment consists of implanting the catheter far in advance of anticipated need, with the external tubing buried under the skin. The catheter is externalized when initiation of dialysis is required. Details of the surgical procedure and management of associated complications are generally lacking. A total of 84 catheters including conventional and extended catheters were embedded and externalized during the study period. Factors influencing duration of embedment, functionality upon externalization, and long-term outcomes were analyzed. Mean duration of embedment was 13.9 months (median 9.4; range .5 to 68.5). Immediate function was exhibited in 85.7% of catheters. Employing laparoscopic revision, 98.8% of embedded catheters were successfully used for peritoneal dialysis. Extended catheters and duration of embedment were important determinants of catheter functionality. Catheters can be embedded for prolonged periods and still result in functional dialysis access when needed. Complications are few and easily managed. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Radiologic Placement of Tunneled Central Venous Catheters in Pediatric Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Ji; Song, Soon Young; Cho, On Koo; Koh, Byung Hee; Kim, Yong Soo; Jeong, Woo Kyoung; Lee, Yong Ho [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    2010-08-15

    We evaluated the technical success and complication rates associated with the radiological placement of tunneled central venous catheters in pediatric patients. Between May 1, 2005 and March 31, 2008, a total of 46 tunneled central venous catheters were placed in 34 children (M:F = 22:12; mean age, 9.9 years [9 months to 16.8 years]). All procedures were performed under ultrasonographic and fluoroscopic guidance. Follow-up data were obtained through the retrospective review of the medical records. We used the Kaplan-Meier survival method for the evaluation of survival rate of the catheters. All procedures were technically successful. The observed periprocedural complications included hematoma formation in three patients. The mean catheter life was 189.3 days (total, 8710 days; range, 7-810). Catheters were removed due to death (n=9), the end of treatment (n=8), catheter sepsis (n=4), malfunction (n=8), and accidental removal (n=4). The rate of catheter sepsis and malfunction was 0.459 and 0.919 for every 1000 catheter days, respectively. The expected mean catheter life was 479.6 days as per the Kaplan- Meier analysis. The results suggest that the radiologic placement of a tunneled central venous catheter is an effective technique with a high technical success rate and low complication rate.

  9. Model Driven Development of Data Sensitive Systems

    DEFF Research Database (Denmark)

    Olsen, Petur

    2014-01-01

    to the values of variables. This theses strives to improve model-driven development of such data-sensitive systems. This is done by addressing three research questions. In the first we combine state-based modeling and abstract interpretation, in order to ease modeling of data-sensitive systems, while allowing...... efficient model-checking and model-based testing. In the second we develop automatic abstraction learning used together with model learning, in order to allow fully automatic learning of data-sensitive systems to allow learning of larger systems. In the third we develop an approach for modeling and model-based...... detection and pushing error detection to earlier stages of development. The complexity of modeling and the size of systems which can be analyzed is severely limited when introducing data variables. The state space grows exponentially in the number of variable and the domain size of the variables...

  10. Recommended Clinical Trial End Points for Dialysis Catheters.

    Science.gov (United States)

    Allon, Michael; Brouwer-Maier, Deborah J; Abreo, Kenneth; Baskin, Kevin M; Bregel, Kay; Chand, Deepa H; Easom, Andrea M; Mermel, Leonard; Mokrzycki, Michele H; Patel, Priti R; Roy-Chaudhury, Prabir; Shenoy, Surendra; Valentini, Rudolph P; Wasse, Haimanot

    2018-03-07

    Central venous catheters are used frequently in patients on hemodialysis as a bridge to a permanent vascular access. They are prone to frequent complications, including catheter-related bloodstream infection, catheter dysfunction, and central vein obstruction. There is a compelling need to develop new drugs or devices to prevent central venous catheter complications. We convened a multidisciplinary panel of experts to propose standardized definitions of catheter end points to guide the design of future clinical trials seeking approval from the Food and Drug Administration. Our workgroup suggests diagnosing catheter-related bloodstream infection in catheter-dependent patients on hemodialysis with a clinical suspicion of infection (fever, rigors, altered mental status, or unexplained hypotension), blood cultures growing the same organism from the catheter hub and a peripheral vein (or the dialysis bloodline), and absence of evidence for an alternative source of infection. Catheter dysfunction is defined as the inability of a central venous catheter to ( 1 ) complete a single dialysis session without triggering recurrent pressure alarms or ( 2 ) reproducibly deliver a mean dialysis blood flow of >300 ml/min (with arterial and venous pressures being within the hemodialysis unit parameters) on two consecutive dialysis sessions or provide a Kt/V≥1.2 in 4 hours or less. Catheter dysfunction is defined only if it persists, despite attempts to reposition the patient, reverse the arterial and venous lines, or forcefully flush the catheter. Central vein obstruction is suspected in patients with >70% stenosis of a central vein by contrast venography or the equivalent, ipsilateral upper extremity edema, and an existing or prior history of a central venous catheter. There is some uncertainty about the specific criteria for these diagnoses, and the workgroup has also proposed future high-priority studies to resolve these questions. Copyright © 2018 by the American Society of

  11. Antimicrobial Agents and Catheter Complications in Outpatient Parenteral Antimicrobial Therapy.

    Science.gov (United States)

    Keller, Sara C; Dzintars, Kathryn; Gorski, Lisa A; Williams, Deborah; Cosgrove, Sara E

    2018-03-01

    Debate about whether certain antimicrobial agents traditionally considered vesicants increase the risk of catheter complications has led to uncertainty in venous catheter placement protocols. To understand whether patients requiring home-based outpatient parenteral antimicrobial therapy (OPAT) should receive peripheral catheters (e.g., midline catheters) versus central venous catheters, and to understand whether certain antimicrobial agents place home-based OPAT patients at higher risk for catheter complications, we investigated associations between antimicrobial agent(s) and catheter complications. We performed a prospective cohort study of patients requiring home-based OPAT discharged from two urban tertiary care academic medical centers, including telephone surveys and chart abstractions. Multivariable Poisson regressions were used to evaluate: (i) associations between antimicrobial agents traditionally considered vesicants, based on pH or osmolarity, and catheter complication rates, and (ii) associations between antimicrobial agent and rates of catheter complications. Vesicant antimicrobials defined using pH or osmolarity criteria were not associated with an increased rate of catheter complications (adjusted incidence rate ratio [aIRR]: 1.63, 95% confidence interval [CI]: 0.89-2.96). Vancomycin was associated with an increased rate of catheter complications, as was daptomycin (aIRR: 2.32 [95% CI: 1.20-4.46] and 4.45 [95% CI: 1.02-19.41], respectively). Staphylococcus aureus infections were also associated with an increased rate of catheter complications (aIRR: 2.13, 95% CI: 1.09-4.19), as were midline catheters (aIRR: 9.44, 95% CI: 2.12-41.97). Our study supports recent guidance identifying vancomycin as a vesicant, among a subset of antimicrobial agents, and removal of pH criteria for identification of vesicants. © 2018 Pharmacotherapy Publications, Inc.

  12. CATHETER DURATION AND THE RISK OF SEPSIS IN PREMATURE BABIES WITH UMBILICAL VEIN CATHETERS

    Directory of Open Access Journals (Sweden)

    Hartojo Hartojo

    2012-01-01

    Full Text Available Umbilical catheters are frequently required in the management of severely ill premature babies. The risk of complications may increase with duration of UVC use. Objective: To determine whether the risk of central line-associated bloodstream infections (CLA-BSIs and sepsis remained constant over the duration of umbilical vein catheters (UVCs in high-risk premature neonates. Methods:retrospective analysis. The data were collected from the medical record of high risk premature neonates who had a UVC placed in neonatal care unit of Husada Utama Hospital between April 1st 2008 to April 30th 2011 with purposive sampling. Catheter duration was observed before and after 14 days on placement. Blood and UVC culture was performed to establish the risk of CLA-BSIs and sepsis. Chi-square and logistic regression analysis were performed in the laboratorium data. Result: A total 44 high risk premature babies with UVCs were enrolled (sepsis group: n = 23 and non sepsis group: n = 21. Baseline demographics were similar between the groups. 15 babies in sepsis group have UVCs duration > 14 days, and 8 babies have UVCs 14 days show blood culture performance in 11 babies with positive evidence, UVCs culture performance is negative in 18 babies (p = 0.456. Burkholderia cepacia and Klebsiella pneumonia mostly appeared in blood culture performance. 25% of UVC culture performance shows Pseudomonas aeroginosa. Conclusions: The catheter duration have no significant difference in risk of sepsis in premature babies with Umbilical Vein Catheters.

  13. Modeling of a Hydraulic Braking System

    OpenAIRE

    Lundin, Christopher

    2015-01-01

    The objective of this thesis is to derive an analytical model representing a reduced form of a mine hoist hydraulic braking system. Based primarily on fluid mechanical and mechanical physical modeling, along with a number of simplifying assumptions, the analytical model will be derived and expressed in the form of a system of differential equations including a set of static functions. The obtained model will be suitable for basic simulation and analysis of system dynamics, with the aim to cap...

  14. Retrograde prostatic urethroplasty with balloon catheter

    International Nuclear Information System (INIS)

    Castaneda, F.; Reddy, P.; Hulbert, J.; Letourneau, J.G.; Hunter, D.W.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1987-01-01

    The authors performed retrograde prostatic urethroplasty in 18 patients using a 25-mm urethroplasty balloon catheter. The procedure was performed on an outpatient basis under local anesthesia. Voiding cystourethrography, retrograde urethrography, rectal US, and MRE imaging were performed before and immediately after the procedure and at 2 weeks and 3, 6, 12, and 18 months. Long-term results at 18 months and possible clinical implications are discussed

  15. Graphical Model Debugger Framework for Embedded Systems

    DEFF Research Database (Denmark)

    Zeng, Kebin

    2010-01-01

    Model Driven Software Development has offered a faster way to design and implement embedded real-time software by moving the design to a model level, and by transforming models to code. However, the testing of embedded systems has remained at the code level. This paper presents a Graphical Model...... Debugger Framework, providing an auxiliary avenue of analysis of system models at runtime by executing generated code and updating models synchronously, which allows embedded developers to focus on the model level. With the model debugger, embedded developers can graphically test their design model...... and check the running status of the system, which offers a debugging capability on a higher level of abstraction. The framework intends to contribute a tool to the Eclipse society, especially suitable for model-driven development of embedded systems....

  16. Pulmonary vein stenosis after catheter ablation: electroporation versus radiofrequency.

    Science.gov (United States)

    van Driel, Vincent J H M; Neven, Kars G E J; van Wessel, Harry; du Pré, Bastiaan C; Vink, Aryan; Doevendans, Pieter A F M; Wittkampf, Fred H M

    2014-08-01

    Radiofrequency ablation inside pulmonary vein (PV) ostia can cause PV stenosis. A novel alternative method of ablation is irreversible electroporation, but the long-term response of PVs to electroporation ablation is unknown. In ten 6-month-old pigs (60-75 kg), the response of PVs to circular electroporation and radiofrequency ablation was compared. Ten consecutive, nonarcing, electroporation applications of 200 J were delivered 5 to 10 mm inside 1 of the 2 main PVs, using a custom-deflectable, 18-mm circular decapolar catheter. Inside the other PV, circular radiofrequency ablation was performed using 30 W radiofrequency applications via an irrigated 4-mm ablation catheter. PV angiograms were made before ablation, immediately after ablation, and after 3-month survival. PV diameters and heart size were measured. With electroporation ablation, PV ostial diameter decreased 11±10% directly after ablation, but had increased 19±11% after 3 months. With radiofrequency ablation, PV ostial diameter decreased 23±15% directly after ablation and remained 7±17% smaller after 3 months compared with preablation diameter despite a 21±7% increase in heart size during aging from 6 to 9 months. In this porcine model, multiple circumferential 200-J electroporation applications inside the PV ostia do not affect PV diameter at 3-month follow-up. Radiofrequency ablation inside PV ostia causes considerable PV stenosis directly after ablation, which persists after 3 months. © 2014 American Heart Association, Inc.

  17. Comparative study on fixation of central venous catheter by suture versus adhesive device.

    Science.gov (United States)

    Molina-Mazón, C S; Martín-Cerezo, X; Domene-Nieves de la Vega, G; Asensio-Flores, S; Adamuz-Tomás, J

    2018-03-27

    To assess the efficacy of a central venous catheter adhesive fixation device (CVC) to prevent associated complications. To establish the need for dressing changes, number of days' catheterization and reasons for catheter removal in both study groups. To assess the degree of satisfaction of personnel with the adhesive system. A, randomized, prospective and open pilot study, of parallel groups, with comparative evaluation between CVC fixation with suture and with an adhesive safety system. The study was performed in the Coronary Unit of the Universitari de Bellvitge Hospital, between April and November 2016. The population studied were patients with a CVC. The results were analyzed using SPSS Statistics software. The study was approved by the Clinical Research Ethics Committee. 100 patients (47 adhesive system and 53 suture) were analyzed. Both groups were homogeneous in terms of demographic variables, anticoagulation and days of catheterization. The frequency of complications in the adhesive system group was 21.3%, while in the suture group it was 47.2% (P=.01). The suture group had a higher frequency of local signs of infection (p=.006), catheter displacement (p=.005), and catheter-associated bacteraemia (P=.05). The use of adhesive fixation was associated with a lower requirement for dressing changes due to bleeding (P=.006). Ninety-six point seven percent of the staff recommended using the adhesive safety system. The catheters fixed with adhesive systems had fewer infectious complications and less displacement. Copyright © 2018 Sociedad Española de Enfermería Intensiva y Unidades Coronarias (SEEIUC). Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Motion-adapted catheter navigation with real-time instantiation and improved visualisation.

    Science.gov (United States)

    Lee, Su-Lin; Kwok, Ka-Wai; Wang, Lichao; Riga, Celia; Bicknell, Colin; Cheshire, Nicholas; Yang, Guang-Zhong

    2013-09-01

    The improvements to catheter manipulation by the use of robot-assisted catheter navigation for endovascular procedures include increased precision, stability of motion and operator comfort. However, navigation through the vasculature under fluoroscopic guidance is still challenging, mostly due to physiological motion and when tortuous vessels are involved. In this paper, we propose a motion-adaptive catheter navigation scheme based on shape modelling to compensate for these dynamic effects, permitting predictive and dynamic navigations. This allows for timed manipulations synchronised with the vascular motion. The technical contribution of the paper includes the following two aspects. Firstly, a dynamic shape modelling and real-time instantiation scheme based on sparse data obtained intra-operatively is proposed for improved visualisation of the 3D vasculature during endovascular intervention. Secondly, a reconstructed frontal view from the catheter tip using the derived dynamic model is used as an interventional aid to user guidance. To demonstrate the practical value of the proposed framework, a simulated aortic branch cannulation procedure is used with detailed user validation to demonstrate the improvement in navigation quality and efficiency.

  19. First In Vivo Use of a Capacitive Micromachined Ultrasound Transducer Array–Based Imaging and Ablation Catheter

    Science.gov (United States)

    Stephens, Douglas N.; Truong, Uyen T.; Nikoozadeh, Amin; Oralkan, Ömer; Seo, Chi Hyung; Cannata, Jonathan; Dentinger, Aaron; Thomenius, Kai; de la Rama, Alan; Nguyen, Tho; Lin, Feng; Khuri-Yakub, Pierre; Mahajan, Aman; Shivkumar, Kalyanam; O’Donnell, Matt; Sahn, David J.

    2012-01-01

    Objectives The primary objective was to test in vivo for the first time the general operation of a new multifunctional intracardiac echocardiography (ICE) catheter constructed with a microlinear capacitive micromachined ultrasound transducer (ML-CMUT) imaging array. Secondarily, we examined the compatibility of this catheter with electroanatomic mapping (EAM) guidance and also as a radiofrequency ablation (RFA) catheter. Preliminary thermal strain imaging (TSI)-derived temperature data were obtained from within the endocardium simultaneously during RFA to show the feasibility of direct ablation guidance procedures. Methods The new 9F forward-looking ICE catheter was constructed with 3 complementary technologies: a CMUT imaging array with a custom electronic array buffer, catheter surface electrodes for EAM guidance, and a special ablation tip, that permits simultaneous TSI and RFA. In vivo imaging studies of 5 anesthetized porcine models with 5 CMUT catheters were performed. Results The ML-CMUT ICE catheter provided high-resolution real-time wideband 2-dimensional (2D) images at greater than 8 MHz and is capable of both RFA and EAM guidance. Although the 24-element array aperture dimension is only 1.5 mm, the imaging depth of penetration is greater than 30 mm. The specially designed ultrasound-compatible metalized plastic tip allowed simultaneous imaging during ablation and direct acquisition of TSI data for tissue ablation temperatures. Postprocessing analysis showed a first-order correlation between TSI and temperature, permitting early development temperature-time relationships at specific myocardial ablation sites. Conclusions Multifunctional forward-looking ML-CMUT ICE catheters, with simultaneous intracardiac guidance, ultrasound imaging, and RFA, may offer a new means to improve interventional ablation procedures. PMID:22298868

  20. First in vivo use of a capacitive micromachined ultrasound transducer array-based imaging and ablation catheter.

    Science.gov (United States)

    Stephens, Douglas N; Truong, Uyen T; Nikoozadeh, Amin; Oralkan, Omer; Seo, Chi Hyung; Cannata, Jonathan; Dentinger, Aaron; Thomenius, Kai; de la Rama, Alan; Nguyen, Tho; Lin, Feng; Khuri-Yakub, Pierre; Mahajan, Aman; Shivkumar, Kalyanam; O'Donnell, Matt; Sahn, David J

    2012-02-01

    The primary objective was to test in vivo for the first time the general operation of a new multifunctional intracardiac echocardiography (ICE) catheter constructed with a microlinear capacitive micromachined ultrasound transducer (ML-CMUT) imaging array. Secondarily, we examined the compatibility of this catheter with electroanatomic mapping (EAM) guidance and also as a radiofrequency ablation (RFA) catheter. Preliminary thermal strain imaging (TSI)-derived temperature data were obtained from within the endocardium simultaneously during RFA to show the feasibility of direct ablation guidance procedures. The new 9F forward-looking ICE catheter was constructed with 3 complementary technologies: a CMUT imaging array with a custom electronic array buffer, catheter surface electrodes for EAM guidance, and a special ablation tip, that permits simultaneous TSI and RFA. In vivo imaging studies of 5 anesthetized porcine models with 5 CMUT catheters were performed. The ML-CMUT ICE catheter provided high-resolution real-time wideband 2-dimensional (2D) images at greater than 8 MHz and is capable of both RFA and EAM guidance. Although the 24-element array aperture dimension is only 1.5 mm, the imaging depth of penetration is greater than 30 mm. The specially designed ultrasound-compatible metalized plastic tip allowed simultaneous imaging during ablation and direct acquisition of TSI data for tissue ablation temperatures. Postprocessing analysis showed a first-order correlation between TSI and temperature, permitting early development temperature-time relationships at specific myocardial ablation sites. Multifunctional forward-looking ML-CMUT ICE catheters, with simultaneous intracardiac guidance, ultrasound imaging, and RFA, may offer a new means to improve interventional ablation procedures.

  1. Crystalline bacterial biofilm formation on urinary catheters by urease-producing urinary tract pathogens: a simple method of control.

    Science.gov (United States)

    Broomfield, Robert J; Morgan, Sheridan D; Khan, Azhar; Stickler, David J

    2009-10-01

    The problem of catheter encrustation stems from infection by urease-producing bacteria. These organisms generate ammonia from urea, elevate the pH of urine and cause crystals of calcium and magnesium phosphates to form in the urine and the biofilm that develops on the catheter. In this study, a laboratory model was used to compare the ability of 12 urease-positive species of urinary tract pathogens to encrust and block catheters. Proteus mirabilis, Proteus vulgaris and Providencia rettgeri were able to raise the urinary pH above 8.3 and produce catheter-blocking crystalline biofilms within 40 h. Morganella morganii and Staphylococcus aureus elevated the pH of urine to 7.4 and 6.9, respectively, and caused some crystal deposition in the biofilms but did not block catheters in the 96 h experimental period. Isolates of Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Serratia marcescens, Pseudomonas aeruginosa and Providencia stuartii were only capable of raising the pH of urine to a maximum of 6.4 and failed to cause crystal deposition in the biofilm. The most effective way to prevent catheter encrustation was shown to be diluting urine and increasing its citrate concentration. This strategy raises the nucleation pH (pH(n)) at which calcium and magnesium phosphates crystallize from urine. Increasing the fluid intake of a healthy volunteer with citrated drinks resulted in urine with a pH(n) of >8.0 in which catheter encrustation was inhibited. It is suggested that this dietary strategy will be an effective means of controlling catheter encrustation, whichever bacterial species is causing the problem.

  2. The humanization of catheter room design: its clinical practice

    International Nuclear Information System (INIS)

    Lin Hanying; Shi Fengxia; Guo Huiying

    2011-01-01

    American scholar Engeer has proposed biological, psychological and sociological medicine pattern, which has been well accepted by the society, It has manifested the medical arena humanism return and has made the profound influence on the nursing development. The idea, 'the human is a whole', has gradually become the mainstream of the nurse service concept, meanwhile, the environment has more and more become a beneficial part for diagnosing and treating in hospitalization. The improvement and more user-friendly design of the diagnosing and treating environment has already become an important ring linked with the whole nursing work. At the beginning of the fitting up design for the Catheter Lab Room of Interventional Radiology in General Hospital of PLA, the authors receive the idea 'the environment experience and admiration of the patient', put more attention to the humanization in the diagnosing and treating environmental construction. The functional compartments are separated clearly. The color, the background music as well as the video are designed to be coordinated with each other in order to produce a relaxing system. Practice for the past three years indicates that the use of humanization environment design can markedly reduce the patient intense and the anxious level in perioperative period, it can also significantly promote the patient to be restored to health. This article will describe user-friendly diagnosing and treating environmental construction practice in the Catheter Lab Room of Interventional Radiology in General Hospital of PLA. (authors)

  3. Hydrological modelling in forested systems

    Science.gov (United States)

    This chapter provides a brief overview of forest hydrology modelling approaches for answering important global research and management questions. Many hundreds of hydrological models have been applied globally across multiple decades to represent and predict forest hydrological p...

  4. Towards Modelling of Hybrid Systems

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2006-01-01

    The article is an attempt to use methods of category theory and topology for analysis of hybrid systems. We use the notion of a directed topological space; it is a topological space together with a set of privileged paths. Dynamical systems are examples of directed topological spaces. A hybrid...... system consists of a number of dynamical systems that are glued together according to information encoded in the discrete part of the system. We develop a definition of a hybrid system as a functor from the category generated by a transition system to the category of directed topological spaces. Its...... directed homotopy colimit (geometric realization) is a single directed topological space. The behavior of hybrid systems can be then understood in terms of the behavior of dynamical systems through the directed homotopy colimit....

  5. Effect of a patency bundle on central venous catheter complications among hospitalized adult patients: a best practice implementation project.

    Science.gov (United States)

    Huang, Vivian

    2018-02-01

    The aim of this project was to improve continuity of care by decreasing central catheter occlusions in adults in two acute care units with high use of central venous catheters. Specific objectives were to introduce a patency bundle and train nurses on thrombolytic administration for timely resolution of catheter occlusions. Central venous catheters are a vital component of medical care of acutely ill hospitalized patients. Occluded catheters delay treatment and can increase infection risk. There are bundles of best practices on catheter insertion, dressing and removal. However, a gap exists in nursing guidance for maintaining and restoring catheter patency. The project used the Joanna Briggs Institute's tools for promoting practice change. Getting Research into Practice (GRiP) and Practical Application of Clinical Evidence System (PACES) assisted with strategy formation and data analysis. Direct observation and medical record review were used for baseline and follow-up audits. Several teaching strategies were employed to educate direct care nurses. Occlusion rates fluctuated greatly above and below baseline rates. Infection rates did not increase with thrombolytic administration. Nurses' compliance with catheter access and flushing techniques doubled. Timeliness of thrombolytic administration increased to 100% compliance. However, patency documentation did not improve. Multi-modal education reached all nurses and contributed to significantly improved compliance with patency best practice. Nurses were empowered to expediently troubleshoot occlusions by using thrombolytics. However, three months of post-implementation data was not enough to demonstrate a continued downward trend in occlusion rates. Thrombolytic administration by nurses on the other adult units and improved patency documentation are in the planning stages.

  6. Service systems concepts, modeling, and programming

    CERN Document Server

    Cardoso, Jorge; Poels, Geert

    2014-01-01

    This SpringerBrief explores the internal workings of service systems. The authors propose a lightweight semantic model for an effective representation to capture the essence of service systems. Key topics include modeling frameworks, service descriptions and linked data, creating service instances, tool support, and applications in enterprises.Previous books on service system modeling and various streams of scientific developments used an external perspective to describe how systems can be integrated. This brief introduces the concept of white-box service system modeling as an approach to mo

  7. Implementation of the updated 2015 Commission for Hospital Hygiene and Infection Prevention (KRINKO) recommendations "Prevention and control of catheter-associated urinary tract infections" in the hospitals in Frankfurt/Main, Germany.

    Science.gov (United States)

    Heudorf, Ursel; Grünewald, Miriam; Otto, Ulla

    2016-01-01

    The Commission for Hospital Hygiene and Infection Prevention (KRINKO) updated the recommendations for the prevention of catheter-associated urinary tract infections in 2015. This article will describe the implementation of these recommendations in Frankfurt's hospitals in autumn, 2015. In two non-ICU wards of each of Frankfurt's 17 hospitals, inspections were performed using a checklist based on the new KRINKO recommendations. In one large hospital, a total of 5 wards were inspected. The inspections covered the structure and process quality (operating instructions, training, indication, the placement and maintenance of catheters) and the demonstration of the preparation for insertion of a catheter using an empty bed and an imaginary patient, or insertion in a model. Operating instructions were available in all hospital wards; approximately half of the wards regularly performed training sessions. The indications were largely in line with the recommendations of the KRINKO. Alternatives to urinary tract catheters were available and were used more often than the urinary tract catheters themselves (15.9% vs. 13.5%). In accordance with the recommendations, catheters were placed without antibiotic prophylaxis or the instillation of antiseptic or antimicrobial substances or catheter flushing solutions. The demonstration of catheter placement was conscientiously performed. Need for improvement was seen in the daily documentation and the regular verification of continuing indication for a urinary catheter, as well as the omission of regular catheter change. Overall, the recommendations of the KRINKO on the prevention of catheter-associated urinary tract infections were adequately implemented. However, it cannot be ruled out that in situations with time pressure and staff shortage, the handling of urinary tract catheters may be of lower quality than that observed during the inspections, when catheter insertion was done by two nurses. Against this background, a sufficient

  8. Implementation of the updated 2015 Commission for Hospital Hygiene and Infection Prevention (KRINKO recommendations “Prevention and control of catheter-associated urinary tract infections” in the hospitals in Frankfurt/Main, Germany

    Directory of Open Access Journals (Sweden)

    Heudorf, Ursel

    2016-06-01

    Full Text Available Aim: The Commission for Hospital Hygiene and Infection Prevention (KRINKO updated the recommendations for the prevention of catheter-associated urinary tract infections in 2015. This article will describe the implementation of these recommendations in Frankfurt’s hospitals in autumn, 2015.Material and methods: In two non-ICU wards of each of Frankfurt’s , inspections were performed using a checklist based on the new KRINKO recommendations. In one large hospital, a total of were inspected. The inspections covered the structure and process quality (operating instructions, training, indication, the placement and maintenance of catheters and the demonstration of the preparation for insertion of a catheter using an empty bed and an imaginary patient, or insertion in a model.Results: Operating instructions were available in all hospital wards; approximately half of the wards regularly performed training sessions. The indications were largely in line with the recommendations of the KRINKO. Alternatives to urinary tract catheters were available and were used more often than the urinary tract catheters themselves (15.9% vs. 13.5%. In accordance with the recommendations, catheters were placed without antibiotic prophylaxis or the instillation of antiseptic or antimicrobial substances or catheter flushing solutions. The demonstration of catheter placement was conscientiously performed. Need for improvement was seen in the daily documentation and the regular verification of continuing indication for a urinary catheter, as well as the omission of regular catheter change.Conclusion: Overall, the recommendations of the KRINKO on the prevention of catheter-associated urinary tract infections were adequately implemented. However, it cannot be ruled out that in situations with time pressure and staff shortage, the handling of urinary tract catheters may be of lower quality than that observed during the inspections, when catheter insertion was done by two

  9. On Verification Modelling of Embedded Systems

    NARCIS (Netherlands)

    Brinksma, Hendrik; Mader, Angelika H.

    Computer-aided verification of embedded systems hinges on the availability of good verification models of the systems at hand. Such models must be much simpler than full design models or specifications to be of practical value, because of the unavoidable combinatorial complexities in the

  10. Balmorel open source energy system model

    DEFF Research Database (Denmark)

    Wiese, Frauke; Bramstoft, Rasmus; Koduvere, Hardi

    2018-01-01

    As the world progresses towards a cleaner energy future with more variable renewable energy sources, energy system models are required to deal with new challenges. This article describes design, development and applications of the open source energy system model Balmorel, which is a result of a l...... transport of local biomass as part of the optimisation and speeding up the model....

  11. Modeling, Control and Coordination of Helicopter Systems

    CERN Document Server

    Ren, Beibei; Chen, Chang; Fua, Cheng-Heng; Lee, Tong Heng

    2012-01-01

    Modeling, Control and Coordination of Helicopter Systems provides a comprehensive treatment of helicopter systems, ranging from related nonlinear flight dynamic modeling and stability analysis to advanced control design for single helicopter systems, and also covers issues related to the coordination and formation control of multiple helicopter systems to achieve high performance tasks. Ensuring stability in helicopter flight is a challenging problem for nonlinear control design and development. This book is a valuable reference on modeling, control and coordination of helicopter systems,providing readers with practical solutions for the problems that still plague helicopter system design and implementation. Readers will gain a complete picture of helicopters at the systems level, as well as a better understanding of the technical intricacies involved. This book also: Presents a complete picture of modeling, control and coordination for helicopter systems Provides a modeling platform for a general class of ro...

  12. Systems Biology—Biomedical Modeling

    OpenAIRE

    Sobie, Eric A.; Lee, Young-Seon; Jenkins, Sherry L.; Iyengar, Ravi

    2011-01-01

    Because of the complexity inherent in biological systems, many researchers frequently rely on a combination of global analysis and computational approaches to gain insight into both (i) how interacting components can produce complex system behaviors, and (ii) how changes in conditions may alter these behaviors. Because the biological details of a particular system are generally not taught along with the quantitative approaches that enable hypothesis generation and analysis of the system, we d...

  13. [Biodegradable catheters and urinary stents. When?

    Science.gov (United States)

    Soria, F; Morcillo, E; López de Alda, A; Pastor, T; Sánchez-Margallo, F M

    2016-10-01

    One of the main wishes in the field of urinary catheters and stents is to arm them with biodegradable characteristics because we consider a failure of these devices the need for retrieval, the forgotten catheter syndrome as well as the adverse effects permanent devices cause after fulfilling their aim. The efforts focused in new designs, coatings and biomaterials aim to increase the biocompatibility of theses internal devices. Lately, there have been correct advances to answer the main challenges regarding biodegradable ureteral devices. Thus, modulation of the rate of degradation has been achieved thanks to new biomaterials and the use of copolymers that enable to choose the time of permanence as it is programmed with conventional double J catheters. Biocompatibility has improved with the use of new polymers that adapt better to the urine. Finally, one of the main problems is elimination of degraded fragments and experimentally it has be demonstrated that new designs elicit controlled degradation, from distal to proximal; using stranding and combination of copolymers degradation may be caused by dilution, reducing fragmentation to the last stages of life of the prosthesis. Moreover, it has been demonstrated that biodegradable catheters potentially may cause less urinary tract infection, less encrustation and predictably they will diminish catheter morbidity, since their degradation process reduces adverse effects. Regarding the development of biodegradable urethral stents, it is necessary to find biomaterials that enable maintaining their biomechanical properties in the long term, keeping open the urethral lumen both in patients with BPH and urethral stenosis. Modulation of the time of degradation of the prosthesis has been achieved, but the appearance of urothelial hyperplasia is still a constant in the initial phases after implantation. The development of drug eluting stents, anti-proliferative or anti-inflammatory, as well as biodegradable stents biocoated is a

  14. Modeling and simulation of systems using Matlab and Simulink

    CERN Document Server

    Chaturvedi, Devendra K

    2009-01-01

    Introduction to SystemsSystemClassification of SystemsLinear SystemsTime-Varying vs. Time-Invariant Systems Lumped vs. Distributed Parameter SystemsContinuous- and Discrete-Time Systems Deterministic vs. Stochastic Systems Hard and Soft Systems Analysis of Systems Synthesis of Systems Introduction to System Philosophy System Thinking Large and Complex Applied System Engineering: A Generic ModelingSystems ModelingIntroduction Need of System Modeling Modeling Methods for Complex Systems Classification of ModelsCharacteristics of Models ModelingMathematical Modeling of Physical SystemsFormulation of State Space Model of SystemsPhysical Systems Theory System Components and Interconnections Computation of Parameters of a Component Single Port and Multiport Systems Techniques of System Analysis Basics of Linear Graph Theoretic ApproachFormulation of System Model for Conceptual SystemFormulation System Model for Physical SystemsTopological RestrictionsDevelopment of State Model of Degenerative SystemSolution of Stat...

  15. Modelling and Verification of Relay Interlocking Systems

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth; Bliguet, Marie Le; Kjær, Andreas

    2010-01-01

    This paper describes how relay interlocking systems as used by the Danish railways can be formally modelled and verified. Such systems are documented by circuit diagrams describing their static layout. It is explained how to derive a state transition system model for the dynamic behaviour of a re...

  16. Compositional Modelling of Stochastic Hybrid Systems

    NARCIS (Netherlands)

    Strubbe, S.N.

    2005-01-01

    In this thesis we present a modelling framework for compositional modelling of stochastic hybrid systems. Hybrid systems consist of a combination of continuous and discrete dynamics. The state space of a hybrid system is hybrid in the sense that it consists of a continuous component and a discrete

  17. Double guiding catheters for complex percutaneous coronary intervention.

    Science.gov (United States)

    Chou, Shing-Hsien; Lin, Chia-Pin; Lin, Yen-Chen; Kuo, Chi-Tai; Lin, Ming-Shyan; Chang, Chi-Jen

    2012-01-01

    A large-lumen guiding catheter is often used for complex percutaneous coronary intervention-particularly when a final kissing-balloon or 2-stent technique is required. However, catheter insertion is sometimes restricted by diseased vascular access sites or a tortuous vascular route.We report 2 cases in which a unique double guiding catheter technique was used to create a lumen of sufficient size for complex percutaneous coronary intervention. In each patient, two 6F guiding catheters were used concurrently to engage the ostium of 1 target vessel. In 1 patient, these catheters were used for the delivery of 2 balloons to complete kissing-balloon dilation after single-stent placement. In the other patient, the catheters were used to deliver 2 stents sequentially to their respective target lesions. The stents were then deployed simultaneously as kissing stents, followed by high-pressure kissing-balloon postdilation.

  18. Balloon catheter versus basket catheter for endoscopic bile duct stone extraction: a multicenter randomized trial.

    Science.gov (United States)

    Ishiwatari, Hirotoshi; Kawakami, Hiroshi; Hisai, Hiroyuki; Yane, Kei; Onodera, Manabu; Eto, Kazunori; Haba, Shin; Okuda, Toshinori; Ihara, Hideyuki; Kukitsu, Takehiro; Matsumoto, Ryusuke; Kitaoka, Keisuke; Sonoda, Tomoko; Hayashi, Tsuyoshi

    2016-04-01

    Endoscopic bile duct stone (BDS) removal is a well-established treatment; however, the preference for basket or balloon catheters for extraction is operator-dependent. We therefore conducted a multicenter prospective randomized trial to compare catheter performance. We enrolled patients with a BDS diameter ≤ 10 mm and common bile duct diameter ≤ 15 mm. Participants were randomly assigned to groups that were treated with basket or balloon catheters between October 2013 and September 2014. The primary endpoint was the rate of complete clearance of the duct; the secondary endpoints were the rate and time to complete clearance in one endoscopic session. We initially enrolled 172 consecutive patients; 14 were excluded after randomization. The complete clearance rates were 92.3 % (72/78) in the balloon group and 80.0 % (64 /80) in the basket group. The difference in the rates between the two groups was 12.3 percentage points, indicating non-inferiority of the balloon method (non-inferiority limit -10 %; P < 0.001 for non-inferiority). Moreover, the balloon was superior to the basket (P = 0.037). The rate of complete clearance in one endoscopic session was 97.4 % using the balloon and 97.5 % using the basket (P = 1.00). The median times to complete clearance in one endoscopic session were 6.0 minutes (1 - 30) and 7.8 minutes (1 - 37) in the balloon and basket groups, respectively (P = 0.15). For extraction of BDSs ≤ 10 mm, complete endoscopic treatment with a single catheter is more likely when choosing a balloon catheter over a basket catheter.University Hospital Medical Information Network Trials Registry: UMIN000011887. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Models of complex attitude systems

    DEFF Research Database (Denmark)

    Sørensen, Bjarne Taulo

    Existing research on public attitudes towards agricultural production systems is largely descriptive, abstracting from the processes through which members of the general public generate their evaluations of such systems. The present paper adopts a systems perspective on such evaluations, understa......Existing research on public attitudes towards agricultural production systems is largely descriptive, abstracting from the processes through which members of the general public generate their evaluations of such systems. The present paper adopts a systems perspective on such evaluations......, understanding them as embedded into a wider attitude system that consists of attitudes towards objects of different abstraction levels, ranging from personal value orientations over general socio-political attitudes to evaluations of specific characteristics of agricultural production systems. It is assumed...... that evaluative affect propagates through the system in such a way that the system becomes evaluatively consistent and operates as a schema for the generation of evaluative judgments. In the empirical part of the paper, the causal structure of an attitude system from which people derive their evaluations of pork...

  20. Embolization of brain arteriovenous malformations using tracker catheter

    International Nuclear Information System (INIS)

    Kim, Sun Yong; Son, Mi Young; Jang, Jae Chun; Hwang, Mi Soo; Park, Bok Hwan

    1990-01-01

    With the recent advance in micro catheters, steerable guide wires, balloons, embolic materials and digital subtraction angiography (DSA), as well as technical refinements in endovascular surgery, there has been a revolution in therapeutic strategies for cerebral arteriovenous malformations (AVMs). We have performed super selective angiography and embolization with Tracker micro catheter about 12 cases of brain AVMs for therapeutic and preoperative aims. This micro catheter and guide wire provided high selectivity of feeding artery, greater maneuverability and useful for deliver various embolus materials

  1. Clinical features of catheter-related candidemia at disease onset.

    Science.gov (United States)

    Yoshino, Yusuke; Wakabayashi, Yoshitaka; Suzuki, Satoshi; Seo, Kazunori; Koga, Ichiro; Kitazawa, Takatoshi; Okugawa, Shu; Ota, Yasuo

    2014-11-01

    Early detection of catheter-related candidemia is necessary to ensure that patients receive prompt and appropriate treatment. The aim of the present case-control study is to investigate the clinical features of catheter-related candidemia at disease onset, so as to determine the clinical indications for empiric antifungal therapy. All 41 cases of catheter-related candidemia from September 2009 to August 2011 at a teaching hospital were included in the present study. To determine the characteristics that were risk factors for developing catheter-related candidemia, we compared all cases of catheter-related candidemia with all 107 cases of catheter-related blood stream infection (CRBSI) caused by non-Candida spp. In comparison with CRBSI due to non-Candida spp., the duration of catheter use was significantly longer in cases of catheter-related candidemia (13.9 ± 9.0 days vs. 23.2 ± 25.2 days). There was also a significant difference in the frequency of pre-antibiotic treatment between catheter-related candidemia and CRBSI due to non-Candida spp. (97.6% [40/41 cases] vs. 44.9% [48/107 cases]). Patients with catheter-related candidemia also had significantly more severe clinical statuses (measured using the Sepsis-related Organ Failure Assessment score) than patients with CRBSI due to non-Candida spp. (7.63 ± 3.65 vs. 5.92 ± 2.81). When compared to patients with CRBSI caused by non-Candida spp., patients with catheter-related candidemia had significantly more severe clinical backgrounds, longer duration of catheter use and more frequent prior administration of antibiotic agents.

  2. Modeling Control Situations in Power System Operations

    DEFF Research Database (Denmark)

    Saleem, Arshad; Lind, Morten; Singh, Sri Niwas

    2010-01-01

    Increased interconnection and loading of the power system along with deregulation has brought new challenges for electric power system operation, control and automation. Traditional power system models used in intelligent operation and control are highly dependent on the task purpose. Thus, a model...... of explicit principles for model construction. This paper presents a work on using explicit means-ends model based reasoning about complex control situations which results in maintaining consistent perspectives and selecting appropriate control action for goal driven agents. An example of power system...... for intelligent operation and control must represent system features, so that information from measurements can be related to possible system states and to control actions. These general modeling requirements are well understood, but it is, in general, difficult to translate them into a model because of the lack...

  3. Holonic Models for Traffic Control Systems

    Science.gov (United States)

    Ciufudean, Calin; Filote, Constantin

    This paper proposes a new time-placed net model for traffic control systems, respectively railway control traffic systems. This model can be interpreted as a holonic one, and contains three modules: Transport Planning Module, Transport Control Module and Priority Control Module. For railway traffic systems we introduce a strategy in a timed-place Petri net model to solve collision and traffic jam problems.

  4. Hydrological modeling in forested systems

    Science.gov (United States)

    H.E. Golden; G.R. Evenson; S. Tian; Devendra Amatya; Ge Sun

    2015-01-01

    Characterizing and quantifying interactions among components of the forest hydrological cycle is complex and usually requires a combination of field monitoring and modelling approaches (Weiler and McDonnell, 2004; National Research Council, 2008). Models are important tools for testing hypotheses, understanding hydrological processes and synthesizing experimental data...

  5. Catheter Fracture and Embolization Related to an Arm Venous Port

    Directory of Open Access Journals (Sweden)

    Brent E. Burbridge

    2011-01-01

    Full Text Available This 55-year-old female had a chest X-ray during a follow-up visit for the management of her breast cancer. The chest X-ray demonstrated an embolized venous catheter superimposed upon the mediastinum. It was determined that the catheter of the patient's arm port had fractured and embolized to the pulmonary circulation. The catheter was retrieved, in the interventional radiology suite, under fluoroscopic guidance. The patient suffered no ill effects. Subsequently, one day later, the old vein port was removed and a new arm port and associated catheter were implanted to facilitate the delivery of the patient's ongoing chemotherapy.

  6. Analog experiment of transarterial catheter hyperthermic infusion in vitro

    International Nuclear Information System (INIS)

    Fan Shufeng Li Zheng; Gu Weizhong; Ru Fuming

    2006-01-01

    Objective: To investigate the factors related to the heating effect by transarterial catheter hyperthermic infusion with the evaluation of the feasibility in controlling the tumor temperature. Methods: Infusing 55-68 degree C liquid at the speed of 10-40 ml/min through 6F, 5F or 3F catheter with different length respectively under the similar clinical condition. The liquid temperature at the terminal exit of the catheter was measured with a digital thermometer. The factors related to the liquid temperature at the exit of the catheter were analyzed by multiple regression analysis. Results: The infusion temperature , rate and the catheter length were the main related factors to the liquid temperature at the exit of the catheter as the condition similar in clinical use. When 60-65 degree C liquid was infused at the rate of 20-40 ml/min through 5F catheter with length of 80 cm, the mean and 95% confident interval of the liquid temperature at the catheter exit were (47.55±0.44) degree C and 44.61-48.49 degree C respectively. Conclusions: The liquid temperature at the exit of infusion catheter can be regulated and controlled through adjusting the liquid perfusion temperature and speed. (authors)

  7. Life-Cycle Models for Survivable Systems

    National Research Council Canada - National Science Library

    Linger, Richard

    2002-01-01

    .... Current software development life-cycle models are not focused on creating survivable systems, and exhibit shortcomings when the goal is to develop systems with a high degree of assurance of survivability...

  8. Model Updating Nonlinear System Identification Toolbox Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology (ZONA) proposes to develop an enhanced model updating nonlinear system identification (MUNSID) methodology that utilizes flight data with...

  9. An expert system for dispersion model interpretation

    International Nuclear Information System (INIS)

    Skyllingstad, E.D.; Ramsdell, J.V.

    1988-10-01

    A prototype expert system designed to diagnose dispersion model uncertainty is described in this paper with application to a puff transport model. The system obtains qualitative information from the model user and through an expert-derived knowledge base, performs a rating of the current simulation. These results can then be used in combination with dispersion model output for deciding appropriate evacuation measures. Ultimately, the goal of this work is to develop an expert system that may be operated accurately by an individual uneducated in meteorology or dispersion modeling. 5 refs., 3 figs

  10. Semantic models for adaptive interactive systems

    CERN Document Server

    Hussein, Tim; Lukosch, Stephan; Ziegler, Jürgen; Calvary, Gaëlle

    2013-01-01

    Providing insights into methodologies for designing adaptive systems based on semantic data, and introducing semantic models that can be used for building interactive systems, this book showcases many of the applications made possible by the use of semantic models.Ontologies may enhance the functional coverage of an interactive system as well as its visualization and interaction capabilities in various ways. Semantic models can also contribute to bridging gaps; for example, between user models, context-aware interfaces, and model-driven UI generation. There is considerable potential for using

  11. Models of the venous system

    DEFF Research Database (Denmark)

    Mehlsen, J

    2000-01-01

    of the venous system require at least three elements: a resistor, a capacitor and an inductor, with the latter being of more importance in the venous than in the arterial system. Non-linearities must be considered in pressure/flow relations in the small venules, during venous collapse, or low flow conditions...

  12. Stochastic Models of Polymer Systems

    Science.gov (United States)

    2016-01-01

    published in non-peer-reviewed journals (N/A for none) The dynamics of stochastic gradient algorithms (submitted); Noisy Hegselmann- Krause Systems...algorithms for big data applications. (2) We studied stochastic dynamics of polymer systems in the mean field limit. (3) We studied noisy Hegselmann- Krause

  13. Switching model photovoltaic pumping system

    Science.gov (United States)

    Anis, Wagdy R.; Abdul-Sadek Nour, M.

    Photovoltaic (PV) pumping systems are widely used due to their simplicity, high reliability and low cost. A directly-coupled PV pumping system is the most reliable and least-cost PV system. The d.c. motor-pump group is not, however, working at its optimum operating point. A battery buffered PV pumping system introduces a battery between the PV array and the d.c. motor-pump group to ensure that the motor-pump group is operating at its optimum point. The size of the battery storage depends on system economics. If the battery is fully charged while solar radiation is available, the battery will discharge through the load while the PV array is disconnected. Hence, a power loss takes place. To overcome the above mentioned difficulty, a switched mode PV pumping is proposed. When solar radiation is available and the battery is fully charged, the battery is disconnected and the d.c. motor-pump group is directly coupled to the PV array. To avoid excessive operating voltage for the motor, a part of the PV array is switched off to reduce the voltage. As a result, the energy loss is significantly eliminated. Detailed analysis of the proposed system shows that the discharged water increases by about 10% when compared with a conventional battery-buffered system. The system transient performance just after the switching moment shows that the system returns to a steady state in short period. The variations in the system parameters lie within 1% of the rated values.

  14. Multiple system modelling of waste management

    International Nuclear Information System (INIS)

    Eriksson, Ola; Bisaillon, Mattias

    2011-01-01

    Highlights: → Linking of models will provide a more complete, correct and credible picture of the systems. → The linking procedure is easy to perform and also leads to activation of project partners. → The simulation procedure is a bit more complicated and calls for the ability to run both models. - Abstract: Due to increased environmental awareness, planning and performance of waste management has become more and more complex. Therefore waste management has early been subject to different types of modelling. Another field with long experience of modelling and systems perspective is energy systems. The two modelling traditions have developed side by side, but so far there are very few attempts to combine them. Waste management systems can be linked together with energy systems through incineration plants. The models for waste management can be modelled on a quite detailed level whereas surrounding systems are modelled in a more simplistic way. This is a problem, as previous studies have shown that assumptions on the surrounding system often tend to be important for the conclusions. In this paper it is shown how two models, one for the district heating system (MARTES) and another one for the waste management system (ORWARE), can be linked together. The strengths and weaknesses with model linking are discussed when compared to simplistic assumptions on effects in the energy and waste management systems. It is concluded that the linking of models will provide a more complete, correct and credible picture of the consequences of different simultaneous changes in the systems. The linking procedure is easy to perform and also leads to activation of project partners. However, the simulation procedure is a bit more complicated and calls for the ability to run both models.

  15. Modeling of power electronic systems with EMTP

    Science.gov (United States)

    Tam, Kwa-Sur; Dravid, Narayan V.

    1989-01-01

    In view of the potential impact of power electronics on power systems, there is need for a computer modeling/analysis tool to perform simulation studies on power systems with power electronic components as well as to educate engineering students about such systems. The modeling of the major power electronic components of the NASA Space Station Freedom Electric Power System is described along with ElectroMagnetic Transients Program (EMTP) and it is demonstrated that EMTP can serve as a very useful tool for teaching, design, analysis, and research in the area of power systems with power electronic components. EMTP modeling of power electronic circuits is described and simulation results are presented.

  16. System Level Modelling and Performance Estimation of Embedded Systems

    DEFF Research Database (Denmark)

    Tranberg-Hansen, Anders Sejer

    The advances seen in the semiconductor industry within the last decade have brought the possibility of integrating evermore functionality onto a single chip forming functionally highly advanced embedded systems. These integration possibilities also imply that as the design complexity increases, so...... an efficient system level design methodology, a modelling framework for performance estimation and design space exploration at the system level is required. This thesis presents a novel component based modelling framework for system level modelling and performance estimation of embedded systems. The framework...... is performed by having the framework produce detailed quantitative information about the system model under investigation. The project is part of the national Danish research project, Danish Network of Embedded Systems (DaNES), which is funded by the Danish National Advanced Technology Foundation. The project...

  17. Network model of security system

    Directory of Open Access Journals (Sweden)

    Adamczyk Piotr

    2016-01-01

    Full Text Available The article presents the concept of building a network security model and its application in the process of risk analysis. It indicates the possibility of a new definition of the role of the network models in the safety analysis. Special attention was paid to the development of the use of an algorithm describing the process of identifying the assets, vulnerability and threats in a given context. The aim of the article is to present how this algorithm reduced the complexity of the problem by eliminating from the base model these components that have no links with others component and as a result and it was possible to build a real network model corresponding to reality.

  18. Indwelling small pleural catheter needle thoracentesis in the management of large pleural effusions.

    Science.gov (United States)

    Grodzin, C J; Balk, R A

    1997-04-01

    To evaluate the clinical safety, efficacy, and cost of a small indwelling pleural catheter (7F, Turkel Safety Thoracentesis System [Sherwood, Davis, and Geck; St. Louis]) vs repeated needle thoracentesis or closed tube thoracostomy as a means to drain a large-volume pleural effusion. Inpatients in a tertiary care university teaching hospital in urban Chicago. Prospective, consecutive patient comparative study using historical controls. Fifty-seven therapeutic aspirations in 23 patients with large pleural effusions as defined by opacification of at least one third of the hemithorax on chest radiography. Patients were excluded if they had a history of thoracic surgery, documented loculations, structural chest abnormalities, severe coagulopathy, or refused to give informed consent. Volume of each pleural aspiration, total fluid removed, pleural fluid lactate dehydrogenase, protein, glucose, cytologic analysis, microbiologic stains, and cultures based on clinical indications. We found that initial thoracentesis and repeated pleural drainage using the indwelling catheter system is a safe, efficacious, and cost-effective procedure that may aid the evacuation and management of a large-volume pleural effusion. There were fewer adverse effects and complications such as pneumothorax, splenic laceration, hemopneumothorax, local pain, dry tap, and hematomas, as compared with previous reports. The overall complication rate was 12% (7/57). There were two pneumothoraces detected (3.5%), one of which required closed tube thoracostomy for treatment (1.75%). A further benefit comes in the form of a significant cost savings at our institution ($80 vs $240) when this needle-catheter system is used in place of closed tube thoracostomy in the drainage of a large-volume pleural effusion. An indwelling pleural catheter with the Turkel safety needle-catheter (as described in the study) can be used to successfully drain the pleural space with reduced morbidity and a significant cost saving

  19. Clinical utility of the Covidien Closure Fast™ Endovenous Radiofrequency Ablation Catheter

    Directory of Open Access Journals (Sweden)

    Braithwaite SA

    2014-06-01

    Full Text Available Simon A Braithwaite,1 Bruce D Braithwaite2 1University College Hospital Medical School, London, UK; 2Department of Cardiovascular Medicine, University of Nottingham, Nottingham, UK Abstract: The Closure Fast™ Endovenous Radiofrequency Ablation Catheter is the latest version of a minimally invasive system for the treatment of patients with superficial venous disease. The Closure Fast™ catheter heats the vein wall to 120°C, causing denaturation of the collagen of the vein wall and contraction of the vessel such that no blood can flow through it. Nearly one million systems have been sold since the product was launched. Many, if not all, patients can be treated under local anesthesia with the Closure Fast™ catheter. Duplex ultrasound reports occlusion rates for the treated vein of 94%–98% at 1 year and 85%–93% at 3 years. The system produces average postoperative pain scores of less than 2 out of 10 on a visual analog score. In the first postoperative week, 76% of patients do not require analgesia. Some 45% of patients return to normal activity on the first postoperative day. Serious complications appear to be rare following the Closure Fast™ procedure. Transient paresthesia occurs in 0.2% of cases, thrombophlebitis in 1%–10%, and thromboembolic events in up to 1.4%, mainly heat-induced thrombosis. Closure Fast™ adds significant costs to treating superficial venous disease but studies have shown it to be cost-effective when used in an office setting. Keywords: Closure Fast, catheter, Endovenous Radiofrequency Ablation Catheter

  20. Modeling Adaptive Behavior for Systems Design

    DEFF Research Database (Denmark)

    Rasmussen, Jens

    1994-01-01

    Field studies in modern work systems and analysis of recent major accidents have pointed to a need for better models of the adaptive behavior of individuals and organizations operating in a dynamic and highly competitive environment. The paper presents a discussion of some key characteristics...... of the predictive models required for the design of work supports systems, that is,information systems serving as the human-work interface. Three basic issues are in focus: 1.) Some fundamental problems in analysis and modeling modern dynamic work systems caused by the adaptive nature of human behavior; 2.......) The basic difference between the models of system functions used in engineering and design and those evolving from basic research within the various academic disciplines and finally 3.) The models and methods required for closed-loop, feedback system design....

  1. Model-based version management system framework

    International Nuclear Information System (INIS)

    Mehmood, W.

    2016-01-01

    In this paper we present a model-based version management system. Version Management System (VMS) a branch of software configuration management (SCM) aims to provide a controlling mechanism for evolution of software artifacts created during software development process. Controlling the evolution requires many activities to perform, such as, construction and creation of versions, identification of differences between versions, conflict detection and merging. Traditional VMS systems are file-based and consider software systems as a set of text files. File based VMS systems are not adequate for performing software configuration management activities such as, version control on software artifacts produced in earlier phases of the software life cycle. New challenges of model differencing, merge, and evolution control arise while using models as central artifact. The goal of this work is to present a generic framework model-based VMS which can be used to overcome the problem of tradition file-based VMS systems and provide model versioning services. (author)

  2. Very Large System Dynamics Models - Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Leonard Malczynski

    2008-10-01

    This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

  3. Test-driven modeling of embedded systems

    DEFF Research Database (Denmark)

    Munck, Allan; Madsen, Jan

    2015-01-01

    To benefit maximally from model-based systems engineering (MBSE) trustworthy high quality models are required. From the software disciplines it is known that test-driven development (TDD) can significantly increase the quality of the products. Using a test-driven approach with MBSE may have...... a similar positive effect on the quality of the system models and the resulting products and may therefore be desirable. To define a test-driven model-based systems engineering (TD-MBSE) approach, we must define this approach for numerous sub disciplines such as modeling of requirements, use cases......, scenarios, behavior, architecture, etc. In this paper we present a method that utilizes the formalism of timed automatons with formal and statistical model checking techniques to apply TD-MBSE to the modeling of system architecture and behavior. The results obtained from applying it to an industrial case...

  4. Precipitation-runoff modeling system; user's manual

    Science.gov (United States)

    Leavesley, G.H.; Lichty, R.W.; Troutman, B.M.; Saindon, L.G.

    1983-01-01

    The concepts, structure, theoretical development, and data requirements of the precipitation-runoff modeling system (PRMS) are described. The precipitation-runoff modeling system is a modular-design, deterministic, distributed-parameter modeling system developed to evaluate the impacts of various combinations of precipitation, climate, and land use on streamflow, sediment yields, and general basin hydrology. Basin response to normal and extreme rainfall and snowmelt can be simulated to evaluate changes in water balance relationships, flow regimes, flood peaks and volumes, soil-water relationships, sediment yields, and groundwater recharge. Parameter-optimization and sensitivity analysis capabilites are provided to fit selected model parameters and evaluate their individual and joint effects on model output. The modular design provides a flexible framework for continued model system enhancement and hydrologic modeling research and development. (Author 's abstract)

  5. An Empirical Model for Energy Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rosewater, David Martin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Scott, Paul [TransPower, Poway, CA (United States)

    2016-03-17

    Improved models of energy storage systems are needed to enable the electric grid’s adaptation to increasing penetration of renewables. This paper develops a generic empirical model of energy storage system performance agnostic of type, chemistry, design or scale. Parameters for this model are calculated using test procedures adapted from the US DOE Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage. We then assess the accuracy of this model for predicting the performance of the TransPower GridSaver – a 1 MW rated lithium-ion battery system that underwent laboratory experimentation and analysis. The developed model predicts a range of energy storage system performance based on the uncertainty of estimated model parameters. Finally, this model can be used to better understand the integration and coordination of energy storage on the electric grid.

  6. Brief History of Agricultural Systems Modeling

    Science.gov (United States)

    Jones, James W.; Antle, John M.; Basso, Bruno O.; Boote, Kenneth J.; Conant, Richard T.; Foster, Ian; Godfray, H. Charles J.; Herrrero, Mario; Howitt, Richard E.; Janssen, Sandor; hide

    2016-01-01

    Agricultural systems science generates knowledge that allows researchers to consider complex problems or take informed agricultural decisions. The rich history of this science exemplifies the diversity of systems and scales over which they operate and have been studied. Modeling, an essential tool in agricultural systems science, has been accomplished by scientists from a wide range of disciplines, who have contributed concepts and tools over more than six decades. As agricultural scientists now consider the next generation models, data, and knowledge products needed to meet the increasingly complex systems problems faced by society, it is important to take stock of this history and its lessons to ensure that we avoid re-invention and strive to consider all dimensions of associated challenges. To this end, we summarize here the history of agricultural systems modeling and identify lessons learned that can help guide the design and development of next generation of agricultural system tools and methods. A number of past events combined with overall technological progress in other fields have strongly contributed to the evolution of agricultural system modeling, including development of process-based bio-physical models of crops and livestock, statistical models based on historical observations, and economic optimization and simulation models at household and regional to global scales. Characteristics of agricultural systems models have varied widely depending on the systems involved, their scales, and the wide range of purposes that motivated their development and use by researchers in different disciplines. Recent trends in broader collaboration across institutions, across disciplines, and between the public and private sectors suggest that the stage is set for the major advances in agricultural systems science that are needed for the next generation of models, databases, knowledge products and decision support systems. The lessons from history should be considered

  7. Formal Modeling and Analysis of Timed Systems

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand; Niebert, Peter

    This book constitutes the thoroughly refereed post-proceedings of the First International Workshop on Formal Modeling and Analysis of Timed Systems, FORMATS 2003, held in Marseille, France in September 2003. The 19 revised full papers presented together with an invited paper and the abstracts...... of two invited talks were carefully selected from 36 submissions during two rounds of reviewing and improvement. All current aspects of formal method for modeling and analyzing timed systems are addressed; among the timed systems dealt with are timed automata, timed Petri nets, max-plus algebras, real......-time systems, discrete time systems, timed languages, and real-time operating systems....

  8. Grey Box Modelling of Hydrological Systems

    DEFF Research Database (Denmark)

    Thordarson, Fannar Ørn

    The main topic of the thesis is grey box modelling of hydrologic systems, as well as formulation and assessment of their embedded uncertainties. Grey box model is a combination of a white box model, a physically-based model that is traditionally formulated using deterministic ordinary differential...... the lack of fit in state space formulation, and further support decisions for a model expansion. By using stochastic differential equations to formulate the dynamics of the hydrological system, either the complexity of the model can be increased by including the necessary hydrological processes...... in the model, or formulation of process noise can be considered so that it meets the physical limits of the hydrological system and give an adequate description of the embedded uncertainty in model structure. The thesis consists of two parts: a summary report and a part which contains six scientific papers...

  9. Antibacterial and anti-encrustation biodegradable polymer coating for urinary catheter.

    Science.gov (United States)

    Dayyoub, Eyas; Frant, Marion; Pinnapireddy, Shashank Reddy; Liefeith, Klaus; Bakowsky, Udo

    2017-10-05

    Bacterial biofilm and crystalline deposits are the common causes of failure of long-term indwelling urinary catheter. Bacteria colonise the catheter surface causing serious infections in the urinary tract and encrustations that can block the catheter and induce trauma in patients. In this study, the strategy used to resist bacterial adhesion and encrustation represents a combination of the antibacterial effects of norfloxacin and silver nanoparticles and the PLGA-based neutralisation of alkali products of urea hydrolysis gained through the degradation of the polymer in an aqueous milieu. Silver nanoparticles were coated with tetraether lipids (TEL) to avoid aggregation when dispersed in acetone and during the film formation. The polymer films loaded with the two antibacterial agents were applied on Polyurethane (PUR) and Silicon sheets. We demonstrated the antibacterial and anti-adhesion effectiveness of the coatings whereby commercially available biocompatible polymers PUR and Silicon were used as controls. Using artificial urine and an in vitro encrustation model, it was shown that the coatings resist the encrustation for at least 2 weeks. This combination of a biodegradable polymer and wide-range antibacterial agents represents a potentially attractive biocompatible coating for urinary catheters. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Ultrasound-guided or landmark techniques for central venous catheter placement in critically ill children.

    Science.gov (United States)

    Oulego-Erroz, Ignacio; González-Cortes, Rafael; García-Soler, Patricia; Balaguer-Gargallo, Mónica; Frías-Pérez, Manuel; Mayordomo-Colunga, Juan; Llorente-de-la-Fuente, Ana; Santos-Herraiz, Paula; Menéndez-Suso, Juan José; Sánchez-Porras, María; Palanca-Arias, Daniel; Clavero-Rubio, Carmen; Holanda-Peña, Mª Soledad; Renter-Valdovinos, Luis; Fernández-De-Miguel, Sira; Rodríguez-Núñez, Antonio

    2018-01-01

    To assess whether ultrasound guidance improves central venous catheter placement outcomes compared to the landmark technique in critically ill children. A prospective multicentre observational study was carried out in 26 paediatric intensive care units over 6 months. Children 0-18 years old who received a temporary central venous catheter, inserted using either ultrasound or landmark techniques, were eligible. The primary outcome was the first-attempt success rate. Secondary outcomes included overall placement success, number of puncture attempts, number of procedures requiring multiple punctures (> 3 punctures), number of procedures requiring punctures at more than one vein site and immediate mechanical complications. To account for potential confounding factors, we used propensity scores. Our primary analysis was based on 1:1 propensity score matching. The association between cannulation technique and outcomes in the matched cohort was estimated using generalized estimating equations and mixed-effects models to account for patient-level and hospital-level confounders. Five hundred central venous catheter-placement procedures involving 354 patients were included. Ultrasound was used for 323 procedures, and the landmark technique was used for 177. Two hundred and sixty-six procedures were matched (133 in the ultrasound group and 133 in the landmark group). Ultrasound was associated with an increase in the first-attempt success rate [46.6 vs. 30%, odds ratio 2.09 (1.26-3.46); p central venous catheter placement in critically ill children.

  11. Meta-analysis of Foley catheter plus misoprostol versus misoprostol alone for cervical ripening.

    Science.gov (United States)

    Chen, Wenhang; Xue, Jing; Gaudet, Laura; Walker, Mark; Wen, Shi Wu

    2015-06-01

    The effectiveness of Foley catheter plus misoprostol for cervical ripening has not been convincingly shown in trials. To summarize the evidence comparing Foley catheter plus misoprostol versus misoprostol alone for cervical ripening. Embase, Medline, and Cochrane Collaboration databases were searched with the terms "Foley catheter," "misoprostol," "cervical ripening," and "labor induction." Randomized controlled trials comparing the methods of cervical ripening for delivery of a viable fetus were included. Study characteristics, quality, and outcomes were recorded. Random-effects models were used to combine data. Eight trials were included, with 1153 patients overall. In a pooled analysis of seven high-quality studies, the combination group had a decreased time to delivery (mean difference -2.36 hours, 95% confidence interval [CI] -4.07 to -0.66; P=0.007). Risk of chorioamnionitis was significantly increased in the combination group (risk ratio [RR] 2.07, 95% CI 1.04-4.13; P=0.04), and that of tachysystole with fetal heart rate changes was decreased (RR 0.58, 95% CI 0.38-0.91; P=0.02). Frequency of cesarean did not differ (P=0.77). The combined use of Foley catheter and misoprostol results in a reduced time to delivery, a reduced frequency tachysystole with fetal heart rate changes, and an increased incidence of chorioamnionitis. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  12. The Guided System Development Framework: Modeling and Verifying Communication Systems

    DEFF Research Database (Denmark)

    Carvalho Quaresma, Jose Nuno; Probst, Christian W.; Nielson, Flemming

    2014-01-01

    . The Guided System Development framework contributes to more secure communication systems by aiding the development of such systems. The framework features a simple modelling language, step-wise refinement from models to implementation, interfaces to security verification tools, and code generation from...... the verified specification. The refinement process carries thus security properties from the model to the implementation. Our approach also supports verification of systems previously developed and deployed. Internally, the reasoning in our framework is based on the Beliefs and Knowledge tool, a verification...

  13. System Advisor Model: Flat Plate Photovoltaic Performance Modeling Validation Report

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, Janine [National Renewable Energy Lab. (NREL), Golden, CO (United States); Whitmore, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kaffine, Leah [National Renewable Energy Lab. (NREL), Golden, CO (United States); Blair, Nate [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron P. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-12-01

    The System Advisor Model (SAM) is a free software tool that performs detailed analysis of both system performance and system financing for a variety of renewable energy technologies. This report provides detailed validation of the SAM flat plate photovoltaic performance model by comparing SAM-modeled PV system generation data to actual measured production data for nine PV systems ranging from 75 kW to greater than 25 MW in size. The results show strong agreement between SAM predictions and field data, with annualized prediction error below 3% for all fixed tilt cases and below 8% for all one axis tracked cases. The analysis concludes that snow cover and system outages are the primary sources of disagreement, and other deviations resulting from seasonal biases in the irradiation models and one axis tracking issues are discussed in detail.

  14. Totally implantable venous catheters for chemotherapy: experience in 500 patients

    Directory of Open Access Journals (Sweden)

    Nelson Wolosker

    Full Text Available CONTEXT: Totally implantable devices are increasingly being utilized for chemotherapy treatment of oncological patients, although few studies have been done in our environment to analyze the results obtained from the implantation and utilization of such catheters. OBJECTIVE: To study the results obtained from the implantation of totally implantable catheters in patients submitted to chemotherapy. TYPE OF STUDY: Prospective. SETTING: Hospital do Câncer A.C. Camargo, São Paulo, Brazil. METHODS: 519 totally implantable catheters were placed in 500 patients submitted to chemotherapy, with preference for the use of the right external jugular vein. Evaluations were made of the early and late-stage complications and patient evolution until removal of the device, death or the end of the treatment. RESULTS: The prospective analysis showed an average duration of 353 days for the catheters. There were 427 (82.2% catheters with no complications. Among the early complications observed, there were 15 pathway hematomas, 8 cases of thrombophlebitis of the distal stump of the external jugular vein and one case of pocket infection. Among the late-stage complications observed, there were 43 infectious complications (0.23/1000 days of catheter use, 11 obstructions (0.06/1000 days of catheter use and 14 cases of deep vein thrombosis (0.07/1000 days of catheter use. Removal of 101 catheters was performed: 35 due to complications and 66 upon terminating the treatment. A total of 240 patients died while the catheter was functioning and 178 patients are still making use of the catheter. CONCLUSION: The low rate of complications obtained in this study confirms the safety and convenience of the use of totally implantable accesses in patients undergoing prolonged chemotherapy regimes.

  15. Coupling population dynamics with earth system models: the POPEM model.

    Science.gov (United States)

    Navarro, Andrés; Moreno, Raúl; Jiménez-Alcázar, Alfonso; Tapiador, Francisco J

    2017-09-16

    Precise modeling of CO 2 emissions is important for environmental research. This paper presents a new model of human population dynamics that can be embedded into ESMs (Earth System Models) to improve climate modeling. Through a system dynamics approach, we develop a cohort-component model that successfully simulates historical population dynamics with fine spatial resolution (about 1°×1°). The population projections are used to improve the estimates of CO 2 emissions, thus transcending the bulk approach of existing models and allowing more realistic non-linear effects to feature in the simulations. The module, dubbed POPEM (from Population Parameterization for Earth Models), is compared with current emission inventories and validated against UN aggregated data. Finally, it is shown that the module can be used to advance toward fully coupling the social and natural components of the Earth system, an emerging research path for environmental science and pollution research.

  16. Extremely low-frame-rate digital fluoroscopy in catheter ablation of atrial fibrillation

    Science.gov (United States)

    Lee, Ji Hyun; Kim, Jun; Kim, Minsu; Hwang, Jongmin; Hwang, You Mi; Kang, Joon-Won; Nam, Gi-Byoung; Choi, Kee-Joon; Kim, You-Ho

    2017-01-01

    Abstract Despite the technological advance in 3-dimensional (3D) mapping, radiation exposure during catheter ablation of atrial fibrillation (AF) continues to be a major concern in both patients and physicians. Previous studies reported substantial radiation exposure (7369–8690 cGy cm2) during AF catheter ablation with fluoroscopic settings of 7.5 frames per second (FPS) under 3D mapping system guidance. We evaluated the efficacy and safety of a low-frame-rate fluoroscopy protocol for catheter ablation for AF. Retrospective analysis of data on 133 patients who underwent AF catheter ablation with 3-D electro-anatomic mapping at our institute from January 2014 to May 2015 was performed. Since January 2014, fluoroscopy frame rate of 4-FPS was implemented at our institute, which was further decreased to 2-FPS in September 2014. We compared the radiation exposure quantified as dose area product (DAP) and effective dose (ED) between the 4-FPS (n = 57) and 2-FPS (n = 76) groups. The 4-FPS group showed higher median DAP (599.9 cGy cm2; interquartile range [IR], 371.4–1337.5 cGy cm2 vs. 392.0 cGy cm2; IR, 289.7–591.4 cGy cm2; P fluoroscopy setting. PMID:28614264

  17. Fibre Bragg grating manometry catheters for in vivo monitoring of peristalsis

    Science.gov (United States)

    Arkwright, John W.; Underhill, Ian

    2017-02-01

    The human gastrointestinal tract or `gut' is one of the body's largest functional systems spanning up to 8 metres in length from beginning to end. It is formed of a series of physiologically different sections that perform the various functions required for the digestion of food, absorption of nutrients and water, and the removal of waste products. To enable the gut to perform correctly it must be able to transport digesta through each section at the appropriate rate, and any breakdown or malfunction of this transport mechanism can have severe consequences to on-going good health. Monitoring motor function deep within the gut is challenging due to the need to monitor over extended lengths with high spatial resolution. Fiber Bragg grating (FBG) manometry catheters provide a near ideal method of monitoring physiologically significant lengths of the gut in a minimally invasive fashion. Following the development by our group of the first viable FBG based manometry catheter we have undertaken a series of clinical investigations in the human esophagus, colon, stomach and small bowel. Each region presents its own technological challenge and has required a range of modifications to the basic catheter design. We present the design of these catheters and clinical results from over 100 in-vivo studies.

  18. Injection of gadolinium contrast through pediatric central venous catheters: a safety study

    International Nuclear Information System (INIS)

    Moriarty, John M.; Ramos, Yanerys; Finn, J.P.; Kung, Geoffrey L.; Moghaddam, Abbas N.; Ennis, Daniel B.

    2012-01-01

    Catheter rupture during CT angiography has prompted policies prohibiting the use of electronic injectors with peripherally inserted central venous catheters (PICCs) not only for CT but also for MRI. Consequently, many institutions mandate hand injection for MR angiography, limiting precision of infusion rates and durations of delivery. To determine whether electronic injection of gadolinium-based contrast media through a range of small-caliber, single-lumen PICCs would be safe without risk of catheter rupture over the range of clinical protocols and determine whether programmed flow rates and volumes were realized when using PICCs for contrast delivery. Experiments were performed and recorded using the Medrad Spectris Solaris EP MR Injection System. PICC sizes, contrast media and flow rates were based on common institutional protocols. No catheters were damaged during any experiments. Mean difference between programmed and delivered volume was 0.07 ± 0.10 mL for all experiments. Reduced flow rates and prolonged injection durations were observed when the injector's pressure-limiting algorithm was triggered, only in protocols outside the clinical range. PICCs commonly used in children can withstand in vitro power injection of gadolinium-based contrast media at protocols significantly above clinical levels. (orig.)

  19. Injection of gadolinium contrast through pediatric central venous catheters: a safety study

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, John M.; Ramos, Yanerys; Finn, J.P. [University of California, Department of Radiological Sciences, David Geffen School of Medicine, Los Angeles, CA (United States); Kung, Geoffrey L. [University of California, Department of Radiological Sciences, David Geffen School of Medicine, Los Angeles, CA (United States); University of California, Biomedical Engineering Interdepartmental Program, Los Angeles, CA (United States); Moghaddam, Abbas N. [University of California, Department of Radiological Sciences, David Geffen School of Medicine, Los Angeles, CA (United States); Amirkabir University of Technology (Tehran Polytechnic), Department of Biomedical Engineering, Tehran (Iran, Islamic Republic of); Ennis, Daniel B. [University of California, Department of Radiological Sciences, David Geffen School of Medicine, Los Angeles, CA (United States); University of California, Biomedical Engineering Interdepartmental Program, Los Angeles, CA (United States); University of California, Biomedical Physics Interdepartmental Program, Los Angeles, CA (United States)

    2012-09-15

    Catheter rupture during CT angiography has prompted policies prohibiting the use of electronic injectors with peripherally inserted central venous catheters (PICCs) not only for CT but also for MRI. Consequently, many institutions mandate hand injection for MR angiography, limiting precision of infusion rates and durations of delivery. To determine whether electronic injection of gadolinium-based contrast media through a range of small-caliber, single-lumen PICCs would be safe without risk of catheter rupture over the range of clinical protocols and determine whether programmed flow rates and volumes were realized when using PICCs for contrast delivery. Experiments were performed and recorded using the Medrad Spectris Solaris EP MR Injection System. PICC sizes, contrast media and flow rates were based on common institutional protocols. No catheters were damaged during any experiments. Mean difference between programmed and delivered volume was 0.07 {+-} 0.10 mL for all experiments. Reduced flow rates and prolonged injection durations were observed when the injector's pressure-limiting algorithm was triggered, only in protocols outside the clinical range. PICCs commonly used in children can withstand in vitro power injection of gadolinium-based contrast media at protocols significantly above clinical levels. (orig.)

  20. Neonatal atrial flutter after insertion of an intracardiac umbilical venous catheter

    Directory of Open Access Journals (Sweden)

    Marcos Moura de Almeida

    2016-03-01

    Full Text Available Abstract Objective: To describe a case of neonatal atrial flutter after the insertion of an intracardiac umbilical venous catheter, reporting the clinical presentation and reviewing the literature on this subject. Case description: A late-preterm newborn, born at 35 weeks of gestational age to a diabetic mother and large for gestational age, with respiratory distress and rule-out sepsis, required an umbilical venous access. After the insertion of the umbilical venous catheter, the patient presented with tachycardia. Chest radiography showed that the catheter was placed in the position that corresponds to the left atrium, and traction was applied. The patient persisted with tachycardia, and an electrocardiogram showed atrial flutter. As the patient was hemodynamically unstable, electric cardioversion was successfully applied. Comments: The association between atrial arrhythmias and misplaced umbilical catheters has been described in the literature, but in this case, it is noteworthy that the patient was an infant born to a diabetic mother, which consists in another risk factor for heart arrhythmias. Isolated atrial flutter is a rare tachyarrhythmia in the neonatal period and its identification is essential to establish early treatment and prevent systemic complications and even death.

  1. Spinal Cord Injury Model System Information Network

    Science.gov (United States)

    ... the UAB-SCIMS Contact the UAB-SCIMS UAB Spinal Cord Injury Model System Newly Injured Health Daily Living Consumer ... Information Network The University of Alabama at Birmingham Spinal Cord Injury Model System (UAB-SCIMS) maintains this Information Network ...

  2. Statistical Model Checking for Stochastic Hybrid Systems

    DEFF Research Database (Denmark)

    David, Alexandre; Du, Dehui; Larsen, Kim Guldstrand

    2012-01-01

    This paper presents novel extensions and applications of the UPPAAL-SMC model checker. The extensions allow for statistical model checking of stochastic hybrid systems. We show how our race-based stochastic semantics extends to networks of hybrid systems, and indicate the integration technique ap...

  3. Systemic, Ecological Model for Rehabilitation Counseling.

    Science.gov (United States)

    Hershenson, David B.

    1998-01-01

    Presents a reformulation of Hershenson's theoretical model for rehabilitation counseling in systemic and ecological terms. This macrosystem is organized by precipitating event of disability and is composed of four systems: consumer, functional, provider, and contextual. Discusses the use of the model for selecting rehabilitation interventions…

  4. Modeling complex work systems - method meets reality

    NARCIS (Netherlands)

    van der Veer, Gerrit C.; Hoeve, Machteld; Lenting, Bert

    1996-01-01

    Modeling an existing task situation is often a first phase in the (re)design of information systems. For complex systems design, this model should consider both the people and the organization involved, the work, and situational aspects. Groupware Task Analysis (GTA) as part of a method for the

  5. System dynamics modelling of situation awareness

    CSIR Research Space (South Africa)

    Oosthuizen, R

    2015-11-01

    Full Text Available . The feedback loops and delays in the Command and Control system also contribute to the complex dynamic behavior. This paper will build on existing situation awareness models to develop a System Dynamics model to support a qualitative investigation through...

  6. Dynamic modeling of the INAPRO aquaponic system

    NARCIS (Netherlands)

    Karimanzira, Divas; Keesman, Karel J.; Kloas, Werner; Baganz, Daniela; Rauschenbach, Thomas

    2016-01-01

    The use of modeling techniques to analyze aquaponics systems is demonstrated with an example of dynamic modeling for the production of Nile tilapia (Oreochromis niloticus) and tomatoes (Solanum lycopersicon) using the innovative double recirculating aquaponic system ASTAF-PRO. For the management

  7. Formal heterogeneous system modeling with SystemC

    DEFF Research Database (Denmark)

    Niaki, Seyed Hosein Attarzadeh; Jakobsen, Mikkel Koefoed; Sulonen, Tero

    2012-01-01

    Electronic System Level (ESL) design of embedded systems proposes raising the abstraction level of the design entry to cope with the increasing complexity of such systems. To exploit the benefits of ESL, design languages should allow specification of models which are a) heterogeneous, to describe...... to focus on specifying the pure functional aspects. A key advantage is that the formalism is used to export the structure and behavior of the models via introspection as an abstract representation for further analysis and synthesis....

  8. Regression Models for Repairable Systems

    Czech Academy of Sciences Publication Activity Database

    Novák, Petr

    2015-01-01

    Roč. 17, č. 4 (2015), s. 963-972 ISSN 1387-5841 Institutional support: RVO:67985556 Keywords : Reliability analysis * Repair models * Regression Subject RIV: BB - Applied Statistics , Operational Research Impact factor: 0.782, year: 2015 http://library.utia.cas.cz/separaty/2015/SI/novak-0450902.pdf

  9. New generation aspiration catheter: Feasibility in the treatment of pulmonary embolism

    Science.gov (United States)

    Heberlein, Wolf E; Meek, Mollie E; Saleh, Omar; Meek, James C; Lensing, Shelly Y; Culp, William C

    2013-01-01

    AIM: To report our preliminary experience with a new generation aspiration catheter in the treatment of symptomatic pulmonary embolism (PE). METHODS: A retrospective database search for pulmonary artery embolectomy since introduction of the Pronto .035” and XL extraction catheter (Vascular Solutions, Minneapolis, MN) at our institution in 10/2009 was performed. Ten consecutive patients were identified in which the Pronto .035” or XL catheter was used between 01/2010 and 03/2013. All patients were referred for catheter based embolectomy due to contraindications to systemic lysis, or for being in such a critical clinical condition that immediate percutaneous treatment deemed warranted. The computed tomography (CT) right to left heart ratio as predictor for the severity of the PE was retrospectively evaluated on standard axial views. The difference between pre- and post-procedure pulmonary pressure measures was taken to assess the procedural effect. RESULTS: Extensive PE was confirmed angiographically in all patients. Measured right- to left ventricle (RV/LV) ratios were elevated beyond one in seven of the eight available CTs. Acute procedural success defined as clinical removal of visible thrombus and improvement in mean pulmonary artery pressure was seen in all recorded patients (n = 8), the mean pulmonary pressures declined from a median (range) of 35.5 (19-46) to 23 (10-37, P = 0.008) mmHg. Neither death nor other complications occurred intra- or immediately periprocedural, yet short term mortality within 30 d was found in 6 out of 9 patients, one patient was lost in follow up. The cause of death within 30 d in the 6 patients was identified as: Circulatory failure in direct connection with the PE (n = 2), stroke, sepsis, or succumbing to malignancy in a hospice setting (n = 2). CONCLUSION: Success in thrombus removal with improved pulmonary hypertension and systemic hypotension suggests this aspiration technique to be effective. Aspiration catheters should be

  10. Noninvasive phase mapping of persistent atrial fibrillation in humans: Comparison with invasive catheter mapping.

    Science.gov (United States)

    Metzner, Andreas; Wissner, Erik; Tsyganov, Alexey; Kalinin, Vitaly; Schlüter, Michael; Lemes, Christine; Mathew, Shibu; Maurer, Tilmann; Heeger, Christian-Hendrik; Reissmann, Bruno; Ouyang, Feifan; Revishvili, Amiran; Kuck, Karl-Heinz

    2017-12-22

    A novel noninvasive epicardial and endocardial electrophysiology system (NEEES) to identify electrical rotors and focal activity in patients with atrial fibrillation (AF) was recently introduced. Comparison of NEEES data with results from invasive mapping is lacking. Six male patients (59 ± 11 years) with persistent AF underwent cardiac mapping with the NEEES, which included the creation of isopotential and phase maps. Then patients underwent catheter mapping using a PentaRay NAV catheter and the CARTO 3 system. Signals acquired by the catheter were analyzed by customized software that applied the same phase mapping algorithm as for the NEEES data. In all patients, noninvasive phase mapping revealed short-lived electrical rotors occurring 1.8 ± 0.3 times per second and demonstrating 1-4 (mean 1.2 ± 0.6) rotation cycles. Most of these rotors (72.7%) aggregated in 2-3 anatomical clusters. In two patients, focal excitation from pulmonary veins was observed. Invasive catheter mapping in the dominant rotor aggregation sites and in the three control sites demonstrated the presence of electrical rotors with properties similar to noninvasively detected rotors. Spearman's correlation coefficient between rotor occurrence rate by noninvasive and invasive mapping was 0.97 (p rotors' cycle length at dominant aggregation sites, scores of their full rotations, and the proportion of rotors with clockwise rotation were not significantly different between the mapping modalities. In patients with persistent AF, phase processing of unipolar electrograms recorded by catheter mapping could reproduce electrical rotors as characterized by NEEES-based phase mapping. © 2017 The Authors. Annals of Noninvasive Electrocardiology Published by Wiley Periodicals, Inc.

  11. Mathematical Modeling Of Life-Support Systems

    Science.gov (United States)

    Seshan, Panchalam K.; Ganapathi, Balasubramanian; Jan, Darrell L.; Ferrall, Joseph F.; Rohatgi, Naresh K.

    1994-01-01

    Generic hierarchical model of life-support system developed to facilitate comparisons of options in design of system. Model represents combinations of interdependent subsystems supporting microbes, plants, fish, and land animals (including humans). Generic model enables rapid configuration of variety of specific life support component models for tradeoff studies culminating in single system design. Enables rapid evaluation of effects of substituting alternate technologies and even entire groups of technologies and subsystems. Used to synthesize and analyze life-support systems ranging from relatively simple, nonregenerative units like aquariums to complex closed-loop systems aboard submarines or spacecraft. Model, called Generic Modular Flow Schematic (GMFS), coded in such chemical-process-simulation languages as Aspen Plus and expressed as three-dimensional spreadsheet.

  12. Systematic modelling and simulation of refrigeration systems

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.; Jakobsen, Arne

    1998-01-01

    The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose of the s......The task of developing a simulation model of a refrigeration system can be very difficult and time consuming. In order for this process to be effective, a systematic method for developing the system model is required. This method should aim at guiding the developer to clarify the purpose...... of the simulation, to select appropriate component models and to set up the equations in a well-arranged way. In this paper the outline of such a method is proposed and examples showing the use of this method for simulation of refrigeration systems are given....

  13. Modeling and analysis of stochastic systems

    CERN Document Server

    Kulkarni, Vidyadhar G

    2011-01-01

    Based on the author's more than 25 years of teaching experience, Modeling and Analysis of Stochastic Systems, Second Edition covers the most important classes of stochastic processes used in the modeling of diverse systems, from supply chains and inventory systems to genetics and biological systems. For each class of stochastic process, the text includes its definition, characterization, applications, transient and limiting behavior, first passage times, and cost/reward models. Along with reorganizing the material, this edition revises and adds new exercises and examples. New to the second edi

  14. Formal heterogeneous system modeling with SystemC

    DEFF Research Database (Denmark)

    Niaki, Seyed Hosein Attarzadeh; Jakobsen, Mikkel Koefoed; Sulonen, Tero

    2012-01-01

    Electronic System Level (ESL) design of embedded systems proposes raising the abstraction level of the design entry to cope with the increasing complexity of such systems. To exploit the benefits of ESL, design languages should allow specification of models which are a) heterogeneous, to describe...

  15. Systems Engineering Model for ART Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Cruz, Carmen Margarita [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rochau, Gary E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wilson, Mollye C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    The near-term objective of the EC team is to establish an operating, commercially scalable Recompression Closed Brayton Cycle (RCBC) to be constructed for the NE - STEP demonstration system (demo) with the lowest risk possible. A systems engineering approach is recommended to ensure adequate requirements gathering, documentation, and mode ling that supports technology development relevant to advanced reactors while supporting crosscut interests in potential applications. A holistic systems engineering model was designed for the ART Energy Conversion program by leveraging Concurrent Engineering, Balance Model, Simplified V Model, and Project Management principles. The resulting model supports the identification and validation of lifecycle Brayton systems requirements, and allows designers to detail system-specific components relevant to the current stage in the lifecycle, while maintaining a holistic view of all system elements.

  16. Modeling aluminum-air battery systems

    Science.gov (United States)

    Savinell, R. F.; Willis, M. S.

    The performance of a complete aluminum-air battery system was studied with a flowsheet model built from unit models of each battery system component. A plug flow model for heat transfer was used to estimate the amount of heat transferred from the electrolyte to the air stream. The effect of shunt currents on battery performance was found to be insignificant. Using the flowsheet simulator to analyze a 100 cell battery system now under development demonstrated that load current, aluminate concentration, and electrolyte temperature are dominant variables controlling system performance. System efficiency was found to decrease as both load current and aluminate concentration increases. The flowsheet model illustrates the interdependence of separate units on overall system performance.

  17. Model-Based Design for Embedded Systems

    CERN Document Server

    Nicolescu, Gabriela

    2009-01-01

    Model-based design allows teams to start the design process from a high-level model that is gradually refined through abstraction levels to ultimately yield a prototype. This book describes the main facets of heterogeneous system design. It focuses on multi-core methodological issues, real-time analysis, and modeling and validation

  18. Critically Important Object Security System Element Model

    Directory of Open Access Journals (Sweden)

    I. V. Khomyackov

    2012-03-01

    Full Text Available A stochastic model of critically important object security system element has been developed. The model includes mathematical description of the security system element properties and external influences. The state evolution of the security system element is described by the semi-Markov process with finite states number, the semi-Markov matrix and the initial semi-Markov process states probabilities distribution. External influences are set with the intensity of the Poisson thread.

  19. A model for international border management systems.

    Energy Technology Data Exchange (ETDEWEB)

    Duggan, Ruth Ann

    2008-09-01

    To effectively manage the security or control of its borders, a country must understand its border management activities as a system. Using its systems engineering and security foundations as a Department of Energy National Security Laboratory, Sandia National Laboratories has developed such an approach to modeling and analyzing border management systems. This paper describes the basic model and its elements developed under Laboratory Directed Research and Development project 08-684.

  20. A strategic review of electricity systems models

    International Nuclear Information System (INIS)

    Foley, A.M.; O Gallachoir, B.P.; McKeogh, E.J.; Hur, J.; Baldick, R.

    2010-01-01

    Electricity systems models are software tools used to manage electricity demand and the electricity systems, to trade electricity and for generation expansion planning purposes. Various portfolios and scenarios are modelled in order to compare the effects of decision making in policy and on business development plans in electricity systems so as to best advise governments and industry on the least cost economic and environmental approach to electricity supply, while maintaining a secure supply of sufficient quality electricity. The modelling techniques developed to study vertically integrated state monopolies are now applied in liberalised markets where the issues and constraints are more complex. This paper reviews the changing role of electricity systems modelling in a strategic manner, focussing on the modelling response to key developments, the move away from monopoly towards liberalised market regimes and the increasing complexity brought about by policy targets for renewable energy and emissions. The paper provides an overview of electricity systems modelling techniques, discusses a number of key proprietary electricity systems models used in the USA and Europe and provides an information resource to the electricity analyst not currently readily available in the literature on the choice of model to investigate different aspects of the electricity system. (author)