Sample records for acute shunt malfunction

  1. Factors influencing shunt malfunction in patients with tuberculous meningitis

    Sudheer Ambekar


    Full Text Available Background: Hydrocephalus secondary to tuberculous meningitis (TBM is a challenging condition to treat. Though ventriculo-peritoneal (VP shunt is an accepted modality of treatment for hydrocephalus in TBM, there is a high rate of complications associated with the same. Objective: The study was planned to evaluate various factors associated with shunt malfunction in patients undergoing VP shunt surgery for hydrocephalus due to TBM. Materials and Methods: A retrospective review of all the patients undergoing VP shunt and shunt revision for TBM between 2004 and 2008 was performed. 449 VP shunt surgeries were performed in 432 patients for hydrocephalus due to TBM. Among these 70 shunt revisions were performed in 53 patients. Results: Shunt malfunction rate in our series was 16.2%. High cerebrospinal fluid (CSF protein concentration (>200 mg/dL was associated with 5 times increased incidence of shunt malfunction. Patients with hyponatremia (Na + <130 mEq/dL prior to surgery had a 3 times increased incidence of shunt malfunction (P < 0.05. Other factors such as duration of symptoms, presence of neurological deficits, Evan′s index, third ventricular diameter, thickness of exudates, presence of infarcts, anemia, CSF cellularity and CSF glucose concentration were not associated with increased incidence of shunt malfunction. Analysis showed that shunt viability was longest in patients with normal serum sodium levels and CSF protein concentration less than 200 mg/dL and shortest in patients with low serum sodium and CSF protein concentration more than 200 mg/dL. Conclusions: Patients with pre-operative hyponatremia and high CSF protein concentration have a higher incidence of shunt malfunction and need to be followed-up closely.

  2. Episodic ventriculomegaly due to hypernatremia mimicking shunt malfunction: case report.

    Jernigan, Sarah C; Stone, Scellig S D; Aronson, Joshua P; Putman, Melissa; Proctor, Mark R


    Patients with shunted hydrocephalus presenting with altered mental status and ventriculomegaly are generally considered to be in shunt failure requiring surgical treatment. The authors describe a case of shunted hydrocephalus secondary to a disseminated neuroectodermal tumor in a pediatric patient in whom rapid fluctuations in sodium levels due to diabetes insipidus repeatedly led to significant changes in ventricle size, with invasively confirmed normal shunt function and low intracranial pressure. This clinical picture exactly mimics shunt malfunction, requires urgent nonsurgical therapy, and underscores the importance of considering serum osmolar abnormalities in the differential diagnosis for ventriculomegaly.

  3. Ventriculoperitoneal shunt malfunction caused by proximal catheter fat obstruction.

    Mizrahi, Cezar José; Spektor, Sergey; Margolin, Emil; Shoshan, Yigal; Ben-David, Eliel; Cohen, José E; Moscovici, Samuel


    Ventriculoperitoneal (VP) shunt placement is the mainstay of treatment for hydrocephalus, yet shunts remain vulnerable to a variety of complications. Although fat droplet migration into the subarachnoid space and cerebrospinal fluid pathways following craniotomy has been observed, a VP shunt obstruction with fat droplets has never been reported to our knowledge. We present the first reported case of VP shunt catheter obstruction by migratory fat droplets in a 55-year-old woman who underwent suboccipital craniotomy for removal of a metastatic tumor of the left medullocerebellar region, without fat harvesting. A VP shunt was inserted 1month later due to communicating hydrocephalus. The patient presented with gait disturbance, intermittent confusion, and pseudomeningocele 21days after shunt insertion. MRI revealed retrograde fat deposition in the ventricular system and VP shunt catheter, apparently following migration of fat droplets from the fatty soft tissue of the craniotomy site. Spinal tap revealed signs of aseptic meningitis. Steroid treatment for aseptic "lipoid" meningitis provided symptom relief. MRI 2months later revealed partial fat resorption and resolution of the pseudomeningocele. VP shunt malfunction caused by fat obstruction of the ventricular catheter should be acknowledged as a possible complication in VP shunts after craniotomy, even in the absence of fat harvesting.

  4. [A case of repeated shunt malfunctions with eosinophilic meningitis caused by silicone allergy].

    Kambara, Mizuki; Miyazaki, Takeshi; Yoshikane, Tsutomu; Sugimoto, Keiji; Akiyama, Yasuhiko


    The ventricular-peritoneal shunt for hydrocephalus is a well-known and established method but is sometimes complicated by shunt malfunction due to several causes. Eosinophilic meningitis is a rare disease, but has occasionally been reported as a cause of shunt malfunction. Here, we report the case of a 74-year-old woman with repeated shunt malfunction and eosinophilic meningitis due to a silicone allergy. Originally, the patient received a ventricular-peritoneal shunt for normal pressure hydrocephalus secondary to subarachnoid hemorrhage. However, shunt malfunction was identified 6 weeks later, and the first shunt revision was performed using a new shunt system from a different company. Further evaluation to identify the cause of the shunt malfunction revealed no abnormal findings, except for eosinophilia in the serum and cerebrospinal fluid. A second shunt malfunction was identified 16 weeks after the first shunt revision. We therefore concluded that eosinophilic meningitis caused by a silicone allergy might be the real culprit and a second shunt revision was performed using a silicone "extracted" tube. Since then, the patient's course has been free from shunt malfunction. In this case, the serum and cerebrospinal fluid eosinophilia were useful markers for identifying the cause of repeated shunt malfunctions. The silicone "extracted" tube may be helpful for diagnosis and therapy.

  5. Biofilm-associated infection: the hidden face of cerebrospinal fluid shunt malfunction.

    Mounier, Roman; Kapandji, Natacha; Birnbaum, Ron; Cook, Fabrice; Rodriguez, Cristophe; Nebbad, Bibba; Lobo, David; Dhonneur, Gilles


    Diagnosis of cerebrospinal fluid (CSF) shunt infection is difficult. Growing evidence links this pattern to biofilm-associated infections (BAI). Biofilm may explain the indolent development of the infection, and the poor efficiency of traditional microbiologic methods. We report the case of a patient admitted for hydrocephalus associated to CSF shunt malfunction. None of the clinical, serum, or CSF laboratory findings were in favor of an infectious process. Only scanning electron microscopy (SEM) revealed the presence of biofilm. Hence, despite a broad CSF shunt infection definition, some infections could remain undiagnosed by the traditional approach. This study is the first to provide some direct evidence for bacterial biofilm-associated CSF shunt infection.

  6. Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study.

    Riva-Cambrin, Jay; Kestle, John R W; Holubkov, Richard; Butler, Jerry; Kulkarni, Abhaya V; Drake, James; Whitehead, William E; Wellons, John C; Shannon, Chevis N; Tamber, Mandeep S; Limbrick, David D; Rozzelle, Curtis; Browd, Samuel R; Simon, Tamara D


    OBJECT The rate of CSF shunt failure remains unacceptably high. The Hydrocephalus Clinical Research Network (HCRN) conducted a comprehensive prospective observational study of hydrocephalus management, the aim of which was to isolate specific risk factors for shunt failure. METHODS The study followed all first-time shunt insertions in children younger than 19 years at 6 HCRN centers. The HCRN Investigator Committee selected, a priori, 21 variables to be examined, including clinical, radiographic, and shunt design variables. Shunt failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection. Important a priori-defined risk factors as well as those significant in univariate analyses were then tested for independence using multivariate Cox proportional hazard modeling. RESULTS A total of 1036 children underwent initial CSF shunt placement between April 2008 and December 2011. Of these, 344 patients experienced shunt failure, including 265 malfunctions and 79 infections. The mean and median length of follow-up for the entire cohort was 400 days and 264 days, respectively. The Cox model found that age younger than 6 months at first shunt placement (HR 1.6 [95% CI 1.1-2.1]), a cardiac comorbidity (HR 1.4 [95% CI 1.0-2.1]), and endoscopic placement (HR 1.9 [95% CI 1.2-2.9]) were independently associated with reduced shunt survival. The following had no independent associations with shunt survival: etiology, payer, center, valve design, valve programmability, the use of ultrasound or stereotactic guidance, and surgeon experience and volume. CONCLUSIONS This is the largest prospective study reported on children with CSF shunts for hydrocephalus. It confirms that a young age and the use of the endoscope are risk factors for first shunt failure and that valve type has no impact. A new risk factor-an existing cardiac comorbidity-was also associated with shunt failure.

  7. Cerebral regional oxygen saturation monitoring in pediatric malfunctioning shunt patients☆,☆☆,★

    Abramo, Thomas J.; Zhou, Chuan; Estrada, Cristina; Drayna, Patrick C.; Locklair, Matthew R.; Miller, Renee; Pearson, Matthew; Tulipan, Noel; Arnold, Donald H.


    Background Shunt malfunction produces increased intracranial pressure causing decreased cerebral regional perfusion and tissue O2sat. Cerebral regional oxygen saturation (rSO2) by near-infrared spectroscopy represents tissue perfusion and oxygen saturation. Cerebral rSO2 is used to detect cerebral ischemia in pediatric clinical settings. Objective The objective of the study was to determine the reliability of cerebral rSO2 in pediatric malfunctioning shunt. Methods A prospective observational study of pediatric patients presented to the pediatric emergency department was conducted. Confirmed malfunctioning shunt subjects had cerebral rSO2 monitoring. Results A total of 131 malfunctioning shunt subjects had cerebral rSO2 monitoring. Patient's central trend and intrasubject variability of cerebral rSO2 readings for left and right probe and malfunction sites (n = 131) are as follows: VariableOverall, mean SO2Distal, mean SO2Proximal, mean rSO2PLeft cerebral rSO2 trend69.1 (10.7)67.7 (9.81)70.0 (11.17).23Right cerebral rSO2 trend71.3 (9.6)70.5 (8.13)71.8 (10.40).42Left cerebral rSO2 variability3.57 (2.04)4.72 (2.55)2.88 (1.24)<.001Right cerebral rSO2 variability3.46 (1.95)3.77 (2.20)3.28 (1.77).19 Intrasubject left and right rSO2 Pearson correlation was −0.46 to 0.98 (mean ± SD, 0.35 ± 0.34; median, 0.34; interquartile range, 0.06–0.61). The correlation coefficients of 99 subjects between left and right rSO2 was significantly different (P < .001), suggesting that intrasubjects' left and right rSO2 are highly correlated. Sample mean difference between left and right rSO2 were −1.7% (95% confidence interval [CI], −1.8 to −1.6; P < .001) supporting overall left lower than right. Intraclass correlation for left rSO2 was 87.4% (95% CI, 87.2%−87.6%), and that for right rSO2 was 83.8% (95% CI, 83.8%−84%), showing intersubject differences accounting for the variation, and relative to intersubject variation, intrasubjects readings are consistent. Intrasubjects

  8. Visual disturbance following shunt malfunction in a patient with congenital hydrocephalus.

    Oyama, Hirofumi; Hattori, Kenichi; Kito, Akira; Maki, Hideki; Noda, Tomoyuki; Wada, Kentaro


    A 25-year-old woman presented with complaints of nausea and headache. She had been treated with a ventriculoperitoneal shunt for hydrocephalus when she was 7 months old. Her bilateral optic discs showed moderate atrophy. Right visual acuity allowed only perception of hand movement and left visual acuity was 0.02 (1.2). Computed tomography (CT) showed mild ventricular dilation but no periventricular lucency. Intracranial pressure (ICP) was not high when the shunt valve was punctured. Her visual acuity deteriorated 5 days after the consultation. She was referred again 8 days after the first consultation. The bilateral optic discs were completely pale. Both pupils were dilated on admission, and the bilateral direct light reflexes were absent. The patient could slightly detect only green light stimulus. CT showed moderate enlargement of the ventricle. ICP was 47 cmH(2)O when the shunt valve was punctured. Shuntgraphy showed obstruction of the shunt at the distal end of peritoneal catheter. Emergent total shunt revision was performed. She could detect dark stimulus and the still-dilated left pupil had recovered direct light reflex on the next day. The visual acuity was 0.01 (0.7) on the left 6 months after the operation, although she was blind in the right eye and the bilateral optic discs were completely pale. Visual loss associated with shunt failure remains a major morbidity in shunted congenital hydrocephalus. Early diagnosis and shunt revision may allow visual recovery.

  9. Acute modified Blalock-Taussing shunt obstruction successfully treated with urokinase and heparin.

    Mizzi, J; Grech, V


    Acute modified Blalock-Tuassig shunt obstruction due to thrombosis may be life-threatening. We report non-invasive relief of shunt obstruction with thrombolysis and heparinisation, a potentially life-saving intervention that is applicable in all settings, including outside tertiary paediatric cardiology centres.

  10. Emergency Portacaval Shunt Versus Rescue Portacaval Shunt in a Randomized Controlled Trial of Emergency Treatment of Acutely Bleeding Esophageal Varices in Cirrhosis—Part 3

    Isenberg, Jon I.; Wheeler, Henry O.; Haynes, Kevin S.; Jinich-Brook, Horacio; Rapier, Roderick; Vaida, Florin; Hye, Robert J.


    Background Emergency treatment of bleeding esophageal varices in cirrhosis is of singular importance because of the high mortality rate. Emergency portacaval shunt is rarely used today because of the belief, unsubstantiated by long-term randomized trials, that it causes frequent portal-systemic encephalopathy and liver failure. Consequently, portacaval shunt has been relegated solely to salvage therapy when endoscopic and pharmacologic therapies have failed. Question: Is the regimen of endoscopic sclerotherapy with rescue portacaval shunt for failure to control bleeding varices superior to emergency portacaval shunt? A unique opportunity to answer this question was provided by a randomized controlled trial of endoscopic sclerotherapy versus emergency portacaval shunt conducted from 1988 to 2005. Methods Unselected consecutive cirrhotic patients with acute bleeding esophageal varices were randomized to endoscopic sclerotherapy (n = 106) or emergency portacaval shunt (n = 105). Diagnostic workup was completed and treatment was initiated within 8 h. Failure of endoscopic sclerotherapy was defined by strict criteria and treated by rescue portacaval shunt (n = 50) whenever possible. Ninety-six percent of patients had more than 10 years of follow-up or until death. Results Comparison of emergency portacaval shunt and endoscopic sclerotherapy followed by rescue portacaval shunt showed the following differences in measurements of outcomes: (1) survival after 5 years (72% versus 22%), 10 years (46% versus 16%), and 15 years (46% versus 0%); (2) median post-shunt survival (6.18 versus 1.99 years); (3) mean requirements of packed red blood cell units (17.85 versus 27.80); (4) incidence of recurrent portal-systemic encephalopathy (15% versus 43%); (5) 5-year change in Child’s class showing improvement (59% versus 19%) or worsening (8% versus 44%); (6) mean quality of life points in which lower is better (13.89 versus 27.89); and (7) mean cost of care per

  11. Rapid resolution of an acute subdural hematoma by increasing the shunt valve pressure in a 63-year-old man with normal-pressure hydrocephalus with a ventriculoperitoneal shunt: a case report and literature review

    Hayes Jackson


    Full Text Available Abstract Introduction Symptomatic subdural hematoma development is a constant concern for patients who have undergone cerebrospinal fluid shunting procedures to relieve symptoms related to normal-pressure hydrocephalus. Acute subdural hematomas are of particular concern in these patients as even minor head trauma may result in subdural hematoma formation. The presence of a ventricular shunt facilitates further expansion of the subdural hematoma and often necessitates surgical treatment, including subdural hematoma evacuation and shunt ligation. Case presentation We present the case of a 63-year-old North American Caucasian man with normal-pressure hydrocephalus with an adjustable valve ventriculoperitoneal shunt who developed an acute subdural hematoma after sustaining head trauma. Conservative treatment was favored over operative evacuation because our patient was neurologically intact, but simple observation was considered to be too high risk in the setting of a low-pressure ventriculoperitoneal shunt. Thus, the valve setting on the ventriculoperitoneal shunt was increased to its maximum pressure setting in order to reduce flow through the shunt and to mildly increase intracranial pressure in an attempt to tamponade any active bleeding and limit hematoma expansion. A repeat computed tomography scan of the head six days after the valve adjustment revealed complete resolution of the acute subdural hematoma. At this time, the valve pressure was reduced to its original setting to treat symptoms of normal-pressure hydrocephalus. Conclusions Programmable shunt valves afford the option for non-operative management of acute subdural hematoma in patients with ventricular shunts for normal-pressure hydrocephalus. As illustrated in this case report, increasing the shunt valve pressure may result in rapid resolution of the acute subdural hematoma in some patients.

  12. Transjugular intrahepatic portosystemic shunt for the management of acute variceal hemorrhage.

    Loffroy, Romaric; Estivalet, Louis; Cherblanc, Violaine; Favelier, Sylvain; Pottecher, Pierre; Hamza, Samia; Minello, Anne; Hillon, Patrick; Thouant, Pierre; Lefevre, Pierre-Henri; Krausé, Denis; Cercueil, Jean-Pierre


    Acute variceal hemorrhage, a life-threatening condition that requires a multidisciplinary approach for effective therapy, is defined as visible bleeding from an esophageal or gastric varix at the time of endoscopy, the presence of large esophageal varices with recent stigmata of bleeding, or fresh blood visible in the stomach with no other source of bleeding identified. Transfusion of blood products, pharmacological treatments and early endoscopic therapy are often effective; however, if primary hemostasis cannot be obtained or if uncontrollable early rebleeding occurs, transjugular intrahepatic portosystemic shunt (TIPS) is recommended as rescue treatment. The TIPS represents a major advance in the treatment of complications of portal hypertension. Acute variceal hemorrhage that is poorly controlled with endoscopic therapy is generally well controlled with TIPS, which has a 90% to 100% success rate. However, TIPS is associated with a mortality of 30% to 50% in such a setting. Emergency TIPS should be considered early in patients with refractory variceal bleeding once medical treatment and endoscopic sclerotherapy failure, before the clinical condition worsens. Furthermore, admission to specialized centers is mandatory in such a setting and regional protocols are essential to be organized effectively. This review article discusses initial management and then focuses on the specific role of TIPS as a primary therapy to control acute variceal hemorrhage, particularly as a rescue therapy following failure of endoscopic approaches.

  13. [Altitude, the ratio of PaO2 to fraction of inspired oxygen, and shunt: impact on the assessment of acute lung injury].

    Pérez-Padilla, J R


    The ratio of PaO2 to the fraction of inspired oxygen (PaO2/FIO2) is commonly used to determine the severity of acute lung injury and acute respiratory distress syndrome (ARDS). The research presented here used computational models of the lung to analyze the effect of altitude on the PaO2/FIO2 ratio and pulmonary shunt. At a given shunt, the PaO2/FIO2 ratio is lower at higher altitudes. Therefore, when evaluating for ARDS based on a PaO2/FIO2 ratio of <200 mm Hg, patients residing at high altitudes will have less shunt and, presumably, less severe lung injury than patients at sea level. This should be taken into consideration when comparing patients from different altitudes. Shunt should more often be measured directly or be estimated assuming a constant arteriovenous oxygen content difference.

  14. Use of a stop-flow programmable shunt valve to maximize CNS chemotherapy delivery in a pediatric patient with acute lymphoblastic leukemia

    Sheri K Palejwala


    Full Text Available Background: The requirement for frequent intraventricular drug delivery in the setting of shunt dependence is particularly challenging in the treatment of central nervous system infection, neoplastic disease, and hemorrhage. This is especially relevant in the pediatric population where both hematogenous malignancy requiring intrathecal drug delivery and shunt-dependent hydrocephalus are more prevalent. Intrathecal and intraventricular chemotherapy agents can be prematurely diverted in these shunt-dependent patients. Case Description: We report the use of a stop-flow programmable shunt valve to maximize delivery of intraventricular chemotherapy in a child with acute lymphoblastic leukemia and disseminated intravascular coagulation who presented with spontaneous intracerebral and intraventricular hemorrhages. The patient then developed posthemorrhagic hydrocephalus and eventually progressed to shunt dependence but still required frequent intraventricular chemotherapy administration. A ventriculoperitoneal shunt, equipped with a valve that allows for near cessation of cerebrospinal fluid flow (Certas; , Codman, Raynham, MA, and a contralateral Ommaya reservoir were inserted to maximize intraventricular dissemination of chemotherapy. Conclusions: To the best of our knowledge, this is the first reported case of the use of a high-resistance programmable valve being used to virtually cease cerebrospinal fluid flow through the distal catheter temporarily in order to maximize intraventricular drug dissemination in a pediatric patient with acute lymphoblastic leukemia.

  15. Ventriculoperitoneal shunt complications needing shunt revision in children: A review of 5 years of experience with 48 revisions

    Rajendra K Ghritlaharey


    Full Text Available Background: The aim of this study was to review the management of ventriculoperitoneal (VP shunt complications in children. Patients and Methods: During the last 5 years (January 1, 2006 to December 31, 2010, 236 VP shunt operations were performed in children under 12 years of age; of these, 40 (16.94% developed shunt complications and those who underwent VP shunt revisions were studied. Results: This prospective study included 40 (28 boys and 12 girls children and required 48 shunt revisions. Complications following VP shunts that required shunt revisions were peritoneal catheter/peritoneal end malfunction (18, shunt/shunt tract infections (7, extrusion of peritoneal catheter through anus (5, ventricular catheter malfunction (4, cerebrospinal fluid (CSF leak from abdominal wound (4, shunt system failure (2, ventricular end/shunt displacement (2, CSF pseudocysts peritoneal cavity (2, extrusion of peritoneal catheter from neck, chest, abdominal scar and through umbilicus, one each. Four-fifth of these shunt complications occurred within 6 months of previous surgery. Surgical procedures done during shunt revisions in order of frequency were revision of peritoneal part of shunt (27, 56.25%, revision of entire shunt system (6, 12.5%, extra ventricular drainage and delayed re-shunt (5, 10.41%, shunt removal and delayed re-shunt (5, 10.41%, opposite side shunting (2, 4.16%, cysts excision and revision of peritoneal catheter (2, 4.16% and revision of ventricular catheter (1, 2.08%. The mortalities following VP shunt operations were 44 (18.64% and following shunt revisions were 4 (10%. Conclusions: VP shunt done for hydrocephalus in children is not only prone for complications and need for revision surgery but also associated with considerable mortality.

  16. A numerical model of the respiratory modulation of pulmonary shunt and PaO2 oscillations for acute lung injury.

    Beda, Alessandro; Jandre, Frederico C; Giannella-Neto, Antonio


    It is an accepted hypothesis that the amplitude of the respiratory-related oscillations of arterial partial pressure of oxygen (DeltaPaO2) is primarily modulated by fluctuations of pulmonary shunt (Deltas), the latter generated mainly by cyclic alveolar collapse/reopening, when present. A better understanding of the relationship between DeltaPaO2, Deltas, and cyclic alveolar collapse/reopening can have clinical relevance for minimizing the severe lung damage that the latter can cause, for example during mechanical ventilation (MV) of patients with acute lung injury (ALI). To this aim, we numerically simulated the effect of such a relationship on an animal model of ALI under MV, using a combination of a model of lung gas exchange during tidal ventilation with a model of time dependence of shunt on alveolar collapse/opening. The results showed that: (a) the model could adequately replicate published experimental results regarding the complex dependence of DeltaPaO2 on respiratory frequency, driving pressure (DeltaP), and positive end-expiratory pressure (PEEP), while simpler models could not; (b) such a replication strongly depends on the value of the model parameters, especially of the speed of alveolar collapse/reopening; (c) the relationship between DeltaPaO2 and Deltas was overall markedly nonlinear, but approximately linear for PEEP>or=6 cmH2O, with very large DeltaPaO2 associated with relatively small Deltas.

  17. Factors affecting ventriculoperitoneal shunt survival in adult patients

    Farid Khan


    Conclusions: Patients with increased age, prolonged hospital stay, GCS score of less than 13, extra-ventricular drains in situ, or excision of brain tumors were more likely to experience early shunt malfunction.

  18. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    Mohammed, Wail


    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  19. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    Mohammed, Wail


    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  20. Rescue endoscopic third ventriculostomy for repeated shunt blockage

    Puneet K Goyal


    Full Text Available The role of endoscopic third ventriculostomy (ETV is getting more popular for all types of hydrocephalus. It has several advantages and is also being considered for malfunctioning of ventriculo-peritoneal shunt. A 16-year-old child had fourteen shunt revisions in his life. He was eventually treated with ETV with successful result. Repeated shunt failure can be an additional indication of ETV.

  1. Ventriculoperitoneal shunt perforations of the gastrointestinal tract.

    Thiong'o, Grace Muthoni; Luzzio, Christopher; Albright, A Leland


    OBJECT The purposes of this study were to evaluate the frequency with which children presented with ventriculoperitoneal (VP) shunt perforations of the gastrointestinal (GI) tract, to determine the type of shunts that caused the perforations, and to compare the stiffness of perforating catheters with the stiffness of catheters from other manufacturers. METHODS Medical records were reviewed of 197 children who were admitted with VP shunt malfunction. Catheter stiffness was evaluated by measuring relative resistance to cross-sectional compression, resistance to column buckling, and elasticity in longitudinal bending. Catheter frictional force was measured per unit length. RESULTS Six children were identified whose VP shunts had perforated the GI tract; 2 shunts subsequently protruded through the anal orifice, 1 protruded through the oral cavity, and 3 presented with subcutaneous abscesses that tracked upward from the intestine to the chest. All perforating shunts were Chhabra shunts. Catheter stiffness and resistance to bending were greatest with a Medtronic shunt catheter, intermediate with a Codman catheter, and least with a Chhabra catheter. Frictional force was greatest with a Chhabra catheter and least with a Medtronic catheter. CONCLUSIONS The frequency of perforations by Chhabra shunts appears to be higher than the frequency associated with other shunts. The increased frequency does not correlate with their stiffness but may reflect their greater frictional forces.

  2. Ventriculoperitoneal Shunting Surgery with Open Distal Shunt Catheter Placement in the Treatment of Hydrocephalus.

    Zhang, Yang; Zhu, Xiaobo; Zhao, Jinchuan; Hou, Kun; Gao, Xianfeng; Sun, Yang; Wang, Wei; Zhang, Xiaona


    Ventriculoperitoneal shunting (VPS) is a major therapy for hydrocephalus, but has a significant risk of device malfunctioning. In this study, we explored a novel distal shunt catheter placement method in VPS for the treatment of hydrocephalus. Five patients with different etiologies of hydrocephalus underwent VPS with open distant shunt catheter attached outside. We analyzed different variables (age, gender, medical history, clinical presentation, indication for surgery and surgical technique, postoperative complications) and occurrence of shunt failure and infection. All hydrocephalus patients who received the distal shunt catheter placed outside can undergo regular VPS again after the condition improves. The modified VPS in the treatment of hydrocephalus with the distal shunt catheter placed outside could potentially reduce the necessity of repeat surgery for addressing the complications caused by catheter obstruction and infections, reduce the chance of adhesions, and would be of benefit to those patients who need future revisions.

  3. Lumboperitoneal shunts: Review of 409 cases

    Yadav Y


    Full Text Available BACKGROUND AND AIMS: A prospective study was carried out to evaluate the lumboperitoneal shunt procedure. MATERIAL AND METHODS: Four hundred and nine patients having communicating hydrocephalus were selected for the procedure during a 10-year period from March 1992 to February 2002. The average follow-up was 45.34 months. RESULTS: Tubercular meningitis (TBM-related hydrocephalus was detected in 285 patients. Forty per cent of the patients were less than 15 years of age. Glasgow Coma Scale (GCS of less than 8 was seen in 40% patients and 14.9% patients were in GCS 13-15. At the time of discharge 56.7% patients improved in their GCS to 13 -15 and 14.9% were in GCS 8 or less. The overall mortality was 5.13% and shunt-related mortality was seen in 2% patients. Shunt malfunction requiring revision was seen in 32 patients (7.8% and the total number of shunt revisions was 44 (11%. Shunt infection was noted in 3.4% patients. CSF leak at the lumbar end occurred in 12 patients. Four patients required conversion of LP shunt to VP shunt. CONCLUSIONS: Lumboperitoneal shunt is an effective shunting procedure in communicating hydrocephalus.

  4. Critical ventriculo-peritoneal shunt failure due to peritoneal tuberculosis: Case report and diagnostic suggestions for abdominal pseudocyst

    Hajime Takase


    Full Text Available Background: Tuberculous peritonitis (TBP is a well-known complication of ventriculo-peritoneal (VP shunt treatment for hydrocephalus resulting from tuberculous meningitis (TBM. However, a case of hydrocephalus unrelated to TBM resulting from VP shunt malfunction due to TBP has not been reported. Case Description: A 21-year-old male presented with nausea, abdominal pain, and headache. VP and cysto-peritoneal (CP shunts had been inserted to treat hydrocephalus due to a suprasellar arachnoid cyst, replaced the VP and removed the CP in his childhood. Computed tomography demonstrated acute hydrocephalus and an abdominal pseudocyst surrounding the distal end of the peritoneal tube. Initial laboratory data showed elevated white blood cell count and C-reactive protein level, but no causative pathogen was identified. External drainage of cerebrospinal fluid (CSF and of the fluid in the peritoneal cyst was established, and empirical antibiotic therapy was initiated. Bacterial cultures eventually revealed Mycobacterium tuberculosis infection, and TBP was diagnosed. The patient responded well to antituberculosis (anti-TB agents and insertion of a ventriculo-pleural shunt. Conclusion: This case highlights the possibility of CSF shunt failure and concomitant neurological sequelae from TB infection even when the pathogen has not invaded the central nervous system, as in TBM. Moreover, TBP is rare in developed countries and therefore may be misdiagnosed because of nonspecific clinical features and low sensitivity of common TB screening methods.

  5. The utility of the plain radiograph ''shunt series'' in the evaluation of suspected ventriculoperitoneal shunt failure in pediatric patients

    Desai, Kapil R.; Babb, James S.; Amodio, John B. [New York University School of Medicine, Department of Radiology, Pediatric Radiology Section, New York, NY (United States)


    To our knowledge, the sensitivity of plain radiography, known as the shunt series, in diagnosing an etiology of ventriculoperitoneal (VP) shunt malfunction in children has not been previously investigated. To determine the accuracy of plain radiography in diagnosing VP shunt failure in children in whom shunt malfunction is clinically suspected. We retrospectively reviewed the charts of 238 children who had undergone plain radiographic examination for evaluation of clinically suspected VP shunt failure over a 5-year period. The results were compared with those of CT, MRI, and nuclear cisternography. Just 6.72% of patients demonstrated plain radiographic signs of shunt failure. Of patients with normal plain radiographs, 43% demonstrated shunt abnormalities on CT, MRI or cisternography. Statistical analysis indicated that no more than 10.46% (P < 0.05) of plain radiographs showed signs of failure and that the sensitivity of plain radiography for the detection of VP shunt failure is no higher than 31%. Furthermore, there was poor agreement between the results of plain radiography and those of CT, MRI and cisternography. Children with clinically suspected VP shunt failure should proceed directly to cross-sectional or nuclear imaging, as plain radiographic examinations have low sensitivity and significant false-negative rates for detecting shunt abnormalities in all-comers. Use of the shunt series should be limited to patients who specifically have suspected mechanical causes of shunt failure. (orig.)

  6. The value of baseline CT head scans in the assessment of shunt complications in hydrocephalus

    Cantrell, P. (Alder Hey Children' s Hospital, Liverpool (United Kingdom)); Fraser, F. (Alder Hey Children' s Hospital, Liverpool (United Kingdom)); Pilling, D. (Alder Hey Children' s Hospital, Liverpool (United Kingdom)); Carty, H. (Alder Hey Children' s Hospital, Liverpool (United Kingdom))


    The purpose of this study was to determine the value of a baseline CT head scan in the assessment of patients who subsequently presented with symptoms which may have been due to shunt complications (such as blockage or infection). In all these patients the shunt had been inserted in the treatment of hydrocephalus. We conclude that the presence of a baseline scan does not add to the interpretation of CT scans done when the patient presents with symptoms of possible shunt malfunction. (orig.)

  7. Relationship between cerebrospinal fluid flow through the ventriculo-peritoneal shunt and computed tomographic images of hydrocephalic patients

    Ikeda, Kiyonobu; Itoh, Haruhide; Someya, Shigeru; Yamamoto, Shinjiro


    Quantitative measurements of cerebrospinal fluid flow through the ventriculo-peritoneal shunt using radioisotope were carried out on 34 hydrocepalic patients (18 children and 16 adults) and the relationship between the flow rates and the computed tomographic (CT) images was studied. 1) The flow rates in the prone position was 0.04 - 0.20(mean +- SD, 0.10 +- 0.05) ml/min in 13 patients whose shunt systems were functioning adequately. There was a good correlation between the flow rates and closing pressures of the shunt valves. 2) The 21 patients with malfunctioning shunt systems were devided into two groups as follows; the obstruction or lower flow group in which the shunt flow was in 0 approx. 0.05 ml/min and the over-flow groups with rates over 0.20 ml/min. In the former group, there were 3 cases in which the shunt flow in a sitting position was very low and the cause of the malfunction was thought to be placement of an inadequate system with a higher pressure valve. 3) In 4 cases of 5 children in which the ventricles were of normal size during shunt malfunction, their ventricular sizes on CT images changed to small or slit-like ventricles after shunt revision. 4) A few cases of hydrocephalic adults, in which the shunt-catheters were thought to be obstructed with no shunt flow in the prone and sitting positions showing no progressive dilatation of the ventricles on CT images, were diagnosed with the added findings of RI cisternography as shunt-dependent arrested hydrocephalus. In the diagnosis of shunt malfunction and selection of the most adequate system in shunt revision, it is necessary to analyze together the data on CT images, quantitative measurement of shunt flow rates and RI cisternography as well as the clinical manifestations.

  8. Vascular collateralization along ventriculoperitoneal shunt catheters in moyamoya disease.

    Singla, Amit; Lin, Ning; Ho, Allen L; Scott, R Michael; Smith, Edward R


    Surgically created openings such as bur holes can serve as avenues for the development of collateral blood supply to the brain in patients with moyamoya disease. When such collateralization occurs through preexisting shunt catheter sites, the potential exists for perioperative stroke if these vessels are damaged during revision of a ventricular catheter for shunt malfunction. In this paper the authors report on a series of patients with a history of ventriculoperitoneal (VP) shunts who later developed moyamoya disease and were found to have spontaneous transdural collateral vessels at ventricular catheter sites readily visualized on diagnostic angiography. A consecutive surgical series of 412 patients with moyamoya disease treated at Boston Children's Hospital from 1990 to 2010 were reviewed to identify patients with concomitant moyamoya and a VP shunt. The clinical records and angiograms of these patients were reviewed to determine the extent of bur hole collaterals through the shunt site. Three patients were identified who had VP shunts placed for hydrocephalus and subsequently developed moyamoya disease. All 3 patients demonstrated spontaneous transdural collaterals at the ventricular catheter bur hole, as confirmed by angiography during the workup for moyamoya disease. No patients required subsequent revision of their ventricular catheters following the diagnosis of moyamoya. All patients have remained stroke free and clinically stable following pial synangiosis. Although the association of moyamoya and shunted hydrocephalus is rare, it may present a significant potential problem for the neurosurgeon treating a shunt malfunction in this patient population, because shunt bur holes may become entry sites for the ingrowth of significant cortical transdural collateral blood supply to the underlying brain. Shunt revision might therefore be associated with an increased risk of postoperative stroke or operative-site hemorrhage in this population if this

  9. Urethral protrusion of the abdominal catheter of ventriculoperitoneal shunt: Case report of extremely rare complication

    Ugur Yazar


    Full Text Available Hydrocephalus in its various forms constitutes one of the major problems in pediatric neurosurgical practice. The placement of a ventriculoperitoneal (VP shunt is the most common form of treatment for hydrocephalus, so that all neurosurgeons struggle with shunt malfunctions and their complications. Well-known complications are connected with the use of the valve systems (malfunction, infectious, overdrainage, secondary craniosynostosis, etc.. We report an unusual case of protruding abdominal catheter from the urethra. This girl had received a VP shunt for hydrocephalus following surgery of posterior fossa medulloblastoma 4 years ago. After admission, the entire system was removed, antibiotic treatment was administered for 2 weeks, and a new VP shunt was placed. The postoperative course was uneventful. This complication is extremely rare.

  10. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis


    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure.

  11. A malfunctioning nasogastric feeding tube

    Emanuele Cereda


    Full Text Available A critical point of nasogastric feeding tube placement, potentially resulting in an unsafe and/or non-effective operation of the device, is the monitoring of its proper placement into the stomach. A properly obtained and interpreted radiograph is currently recommended to confirm placement. We reported the case of a 68-year-old demented woman referred for complicated dysphagia. A nasogastric tube was blindly inserted and its placement was confirmed by the radiologist. Enteral nutrition was initiated but the patient began to vomit immediately. After reviewing the radiograph it was understood that a gastric loop in the tube and its tip pointing upwards did not allow a safe infusion of the feeding formula. It is not enough having the radiologist reporting that a nasogastric feeding tube is placed in the stomach; the inclusion in the report of specific warnings on any potential cause of malfunctioning of the device should be considered. The presence of a gastric loop should be taken into account as a cause of potential malfunctioning.

  12. Complications and subsequent removal of retained shunt hardware after endoscopic third ventriculostomy: case series.

    Pindrik, Jonathan; Jallo, George I; Ahn, Edward S


    This case series highlights multiple complications and subsequent removal of retained shunt hardware in pediatric patients after successful endoscopic third ventriculostomy (ETV). Removal or retention of existing shunt hardware following ETV represents an important dilemma. Prior studies have reported infections and organ perforation related to nonfunctioning shunts but none in the context of successful ETV. Data obtained in 3 children with hydrocephalus treated at the authors' institution were retrospectively reviewed after the patients experienced complications due to retained shunt hardware following ETV. Etiologies of hydrocephalus included tectal glioma and intraventricular hemorrhage. All 3 patients had a history of multiple shunt revisions and underwent urgent ETV in the setting of a shunt malfunction. In each case, the entire shunt system was left in situ, but it became the source of subsequent complications. Two of the 3 patients presented with the shunt infected by gram-negative bacilli 10 days and 4.5 months postoperatively, respectively. The remaining patient experienced wound dehiscence over the shunt valve 4.5 months after ETV. In all patients, the complications were managed successfully by removing the shunt hardware. None of the patients required repeat shunt insertion from the time of removal throughout the follow-up period (mean 24 months, range 9-36 months). During the study period, a total of 6 patients with indwelling shunt hardware underwent ETV with the expectation of being shunt independent. Among these 6 patients, 3 experienced no complications from the retained hardware whereas 3 patients (50%) ultimately experienced adverse consequences related to retained hardware. This case series illustrates complications involving retained shunt hardware after successful ETV. These examples support consideration of shunt removal at the time of ETV in the appropriate context.

  13. Two-port laparoscopic management of a giant pseudocyst complicating ventriculoperitoneal shunt

    Sandesh V Parelkar


    Full Text Available Insertion of a ventriculo-peritoneal (VP shunt is the most common operative procedure for the treatment of hydrocephalus in children. Of the several causes of shunt malfunction, cerebrospinal fluid (CSF pseudocyst is relatively uncommon. There are several modalities to treat a CSF pseudocyst. Laparotomy is required, at times, more than once. We managed a patient of CSF pseudocyst with two-port laparoscopy, by deroofing the psuedocyst and repositioning of the shunt. This minimally invasive technique avoids morbidity associated with laparotomy and aids in early recovery.

  14. Enhanced Piezoelectric Shunt Design

    Chul H. Park


    Full Text Available Piezoceramic material connected to an electronic shunt branch circuit has formed a successful vibration reduction device. One drawback of the conventional electronic shunt circuit is the large inductance required when suppressing low frequency vibration modes. Also, the large internal resistance associated with this large inductance exceeds the optimal design resistance needed for low frequency vibration suppression. To solve this problem, a modified and enhanced piezoelectric shunt circuit is designed and analyzed by using mechanical-electrical analogies to present the physical interpretation. The enhanced shunt circuit developed in this paper is proved to significantly reduce the targeted vibration mode of a cantilever beam, theoretically and experimentally.

  15. Endoscopic Third Ventriculostomy in Previously Shunted Children

    Eva Brichtova


    Full Text Available Endoscopic third ventriculostomy (ETV is a routine and safe procedure for therapy of obstructive hydrocephalus. The aim of our study is to evaluate ETV success rate in therapy of obstructive hydrocephalus in pediatric patients formerly treated by ventriculoperitoneal (V-P shunt implantation. From 2001 till 2011, ETV was performed in 42 patients with former V-P drainage implantation. In all patients, the obstruction in aqueduct or outflow parts of the fourth ventricle was proved by MRI. During the surgery, V-P shunt was clipped and ETV was performed. In case of favourable clinical state and MRI functional stoma, the V-P shunt has been removed 3 months after ETV. These patients with V-P shunt possible removing were evaluated as successful. In our group of 42 patients we were successful in 29 patients (69%. There were two serious complications (4.7%—one patient died 2.5 years and one patient died 1 year after surgery in consequence of delayed ETV failure. ETV is the method of choice in obstructive hydrocephalus even in patients with former V-P shunt implantation. In case of acute or scheduled V-P shunt surgical revision, MRI is feasible, and if ventricular system obstruction is diagnosed, the hydrocephalus may be solved endoscopically.

  16. Lumbar peritoneal shunt

    Yadav Yad


    Full Text Available A lumbar peritoneal (LP shunt is a technique of cerebrospinal fluid (CSF diversion from the lumbar thecal sac to the peritoneal cavity. It is indicated under a large number of conditions such as communicating hydrocephalus, idiopathic intracranial hypertension, normal pressure hydrocephalus, spinal and cranial CSF leaks, pseudomeningoceles, slit ventricle syndrome, growing skull fractures which are difficult to treat by conventional methods (when dural defect extends deep in the cranial base or across venous sinuses and in recurrent cases after conventional surgery, raised intracranial pressure following chronic meningitis, persistent bulging of craniotomy site after operations for intracranial tumors or head trauma, syringomyelia and failed endoscopic third ventriculostomy with a patent stoma. In spite of the large number of indications of this shunt and being reasonably good, safe, and effective, very few reports about the LP shunt exist in the literature. This procedure did not get its due importance due to some initial negative reports. This review article is based on search on Google and PubMed. This article is aimed to review indications, complications, results, and comparison of the LP shunt with the commonly practiced ventriculoperitoneal (VP shunt. Shunt blocks, infections, CSF leaks, overdrainage and acquired Chiari malformation (ACM are some of the complications of the LP shunt. Early diagnosis of overdrainage complications and ACM as well as timely appropriate treatment especially by programmable shunts could decrease morbidity. Majority of recent reports suggest that a LP shunt is a better alternative to the VP shunt in communicating hydrocephalus. It has an advantage over the VP shunt of being completely extracranial and can be used under conditions other than hydrocephalus when the ventricles are normal sized or chinked. More publications are required to establish its usefulness in the treatment of wide variety of indications.

  17. Return to the emergency department after ventricular shunt evaluation.

    Sarda, Samir; Simon, Harold K; Hirsh, Daniel A; Wang, Andrew; Shane Tubbs, R; Chern, Joshua J


    OBJECT Patients with CSF shunts are medically complex and frequently present to the emergency department (ED) with suspected shunt malfunction. After adequate evaluation in the ED and proper disposition, some patients return to the ED within a short period of time. In this study, the authors examined the reasons for ED revisits within 7 days of the index ED visit to discern possible preventable returns. METHODS There were 3080 index ED visits made by patients with shunted hydrocephalus between 2010 and 2013. Index ED visits preceded by another ED visit or neurosurgical procedure within 60 days were excluded. Index ED visits for reasons unrelated to shunt function and those that led directly to admissions and shunt revision surgeries were also excluded. The remaining 1509 ED visits were eligible for analysis in this study. Final dispositions from the index ED visit included home (1176 cases), admission to the neurosurgery service for observation (134 cases), and admission to other services (199 cases). Subsequent events within 7 days, including ED revisits, hospital admissions, and shunt-related surgery were recorded, and reasons for the ED revisits were categorized based on whether the visit was related to shunt function concerns. Clinical and socioeconomic factors were analyzed for their association with ED revisits by using statistical methods. RESULTS Of the 1176 patients discharged home from the ED after shunt function evaluation, 101 (8.6%) returned to the ED within 7 days. Of the 134 patients admitted to the neurosurgery service for observation only, 8 (6.0%) returned to the ED within 7 days of discharge. Of the 199 patients admitted to hospital services other than neurosurgery, 13 (6.5%) returned to the ED within 7 days of discharge. The reasons for ED revisits vary (total of 122 visits combining the 3 groups), but at least 60% of the revisits were clearly unrelated to shunt function. A younger age, daytime arrival to the ED, and living within the

  18. CSF hydrothorax without intrathoracic catheter migration in children with ventriculoperitoneal shunt

    Joon-Hyung Kim


    Full Text Available Background: Thoracic complications of ventriculoperitoneal (VP shunts have been extensively reported in the literature. Cerebrospinal fluid (CSF hydrothorax without catheter migration, however, has been rarely described and poorly understood. Case Description: We describe development of pleural effusion and respiratory distress in a 3-year-old boy with no evidence of VP shunt catheter displacement on plain radiograph and stable ventricle size on rapid sequence magnetic resonance imaging (MRI brain. Chest X-ray revealed complete opacity of right hemithorax. Pleural effusion was consistent with transudate. Beta-2 transferrin returned positive. The patient underwent externalization of VP shunt, and upon resolution of effusion, re-internalization with new distal shunt catheter. A literature review of CSF hydrothorax in children without intrathoracic shunt migration was performed. Eleven cases were identified in the English literature. Age at VP shunt placement ranged from birth to 8 years of age. Interval from VP shunt placement to CSF hydrothorax ranged from 1.5 months to 5 years. History of shunt revision was reported in two cases. Presenting symptoms also included ascites and inguinal hernia or hydrocele. Reported diagnostic studies consist of CSF culture, radionuclide shuntogram, beta-2 transferrin, and beta-trace protein. Laterality of the VP shunt and development of pleural effusion were predominantly right sided. Definitive surgical treatment included VA shunt, repositioning of the peritoneal catheter, and endoscopic choroid plexus coagulation. Conclusion: CSF hydrothorax is a rare thoracic complication of VP shunt placement with no radiographic evidence of shunt migration or malfunction. Postulated mechanisms include limited peritoneal capacity to resorb CSF in children and microscopic communications present in congenital diaphragmatic hiatuses.

  19. Malfunction of Totally Implantable Central Venous Ports



    Full Text Available Background Malfunctions of totally implantable central venous ports (TICVPs have become a problem, as the usage of TICVPs has increased enormously. Objectives This study evaluated factors related with catheter malfunctions of TICVPs. Patients and Methods Between January 2010 and June 2012, 1,740 TICVPs in 1,740 patients (874 men and 866 women with an average age of 57.7 ± 12.8 years (range: 15 - 91 years were implanted by an interventional radiology team at our institute. Catheter malfunctions were retrospectively analyzed. In the prospective study, we randomly allocated 176 patients to two kinds of TICVPs in a 1:1 assignment ratio. The primary outcome was the malfunction of TICVPs. Results In the retrospective study, the 32 malfunctioning TICVPs were caused by fibrin sheath formations (n = 15, chamber thrombosis (n = 8, TICVP rotation (n = 5, catheter migration (n = 2, and blood clots within the catheters (n = 2. Multivariate analysis showed that being female was a significant factor for poor patency rates of TICVPs (hazard ratio: 5.06; 95% confidence interval (CI 1.32 - 19.46, P = 0.018. In the prospective study, two chamber thromboses occurred in Celsite® (n = 1 and Humanport® (n = 1. The primary patency rates of both Celsite® and Humanport® were 98.9% at 6 months, respectively. Conclusion Our data suggest that catheter malfunctions of TICVPs are more common in females than males. The incidence of TICVP malfunctions does not differ between the two devices (Celsite® vs. Humanport®.

  20. Hydrocephalus and Shunts

    SBA National Resource Center: 800-621-3141 Hydrocephalus and Shunts Approximately 80% of people with SB have Hydrocephalus Hydrocephalus means there is a build-up of cerebrospinal also called CSF, around ...

  1. Distal splenorenal shunt

    ... path. As a result, swollen blood vessels called varices form. They develop thin walls that can break ... or x-rays show that you have bleeding varices. Distal splenorenal shunt surgery reduces pressure on the ...

  2. Pathophysiology of shunt dysfunction in shunt treated hydrocephalus

    Blegvad, C.; Skjolding, A D; Broholm, H


    We hypothesized that shunt dysfunction in the ventricular catheter and the shunt valve is caused by different cellular responses. We also hypothesized that the cellular responses depend on different pathophysiological mechanisms....

  3. residue and shunting pinholes

    Gorji, Nima E.


    The present work considers two observable phenomena through the experimental fabrication and electrical characterization of the rf-sputtered CdS/CdTe thin film solar cells that extremely reduce the overall conversion efficiency of the device: CdCl2 residue on the surface of the semiconductor and shunting pinholes. The former happens through nonuniform treatment of the As-deposited solar cells before annealing at high temperature and the latter occurs by shunting pinholes when the cell surface is shunted by defects, wire-like pathways or scratches on the metallic back contact caused from the external contacts. Such physical problems may be quite common in the experimental activities and reduce the performance down to 4-5 % which leads to dismantle the device despite its precise fabrication. We present our electrical characterization on the samples that received wet CdCl2 surface treatment (uniform or nonuniform) and are damaged by the pinholes.

  4. Percutaneous gastrostomy tube placement in patients with ventriculoperitoneal shunts

    Sane, S.S.; Towbin, A.; Bergey, E.A.; Kaye, R.D.; Fitz, C.R.; Albright, L.; Towbin, R.B. [Department of Radiology, Children`s Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, PA 15213 (United States)


    Objective. The purpose of this study is to determine the risk of CNS and/or peritoneal infection in children with ventriculoperitoneal shunts in whom a percutaneous gastrostomy tube is placed. Materials and methods. We placed 205 gastrostomy or gastrojejunostomy tubes from January of 1991 to December 1996. Twenty-three patients (10 boys, 13 girls) had ventriculoperitoneal shunts at the time of placement. All shunts were placed at least 1 month prior to placement of the gastrostomy tube. The patients ranged in age from 8 months to 16 years with a mean age of 6 years, 9 months. Patient weight ranged from 2 kg to 60 kg. All 23 children required long-term nutritional support due to severe neurologic impairment. No prophylactic antibiotics were given prior to the procedure. Of the patients, 21/23 had a 14-F Sacks-Vine gastrostomy tube with a fixed terminal retention device inserted, using percutaneous fluoroscopic antegrade technique. Two of the 23 patients had a Ross 14-F Flexi-flo gastrostomy tube which required a retrograde technique due to a small caliber esophagus in these children. Results. All 23 children had technically successful placements of percutaneous gastrostomy (7) or gastrojejunostomy (16) tubes. Of the children, 21/23 (91 %) had no complications from the procedure. Two of 23 (9 %) patients demonstrated signs of peritonitis after placement of their gastrostomy tubes and subsequently had shunt infections. In both, children CSF culture grew gram-positive cocci. The antegrade technique was used in both children who developed peritonitis. Conclusion. Our study indicates children with ventriculoperitoneal shunts who undergo percutaneous gastrostomy are at greater risk for infection and subsequent shunt malfunction. Therefore, we recommend prophylactic antibiotic therapy to cover for skin and oral flora. (orig.) With 1 fig., 7 refs.

  5. Post-Operative Complications of Ventriculoperitoneal Shunt in Hydrocephalic Pediatric Patients-Nursing Care

    Efstratios Athanasakis


    Full Text Available Introduction: Hydrocephalus is the most common congenital abnormality of the central nervous system ininfants. Many cases of hydrocephalic children are described since ancient times. It is characterized by excessiveaccumulation of cerebrospinal fluid in the ventricles of the brain. Its symptomatology during infanthood or earlychildhood is characterized by swelling of the head, protrusion of the forehead and brain atrophy. All thesesymptoms appear due to increased cerebrospinal fluid volume, increased intracranial pressure and dilatation ofthe ventricular walls.Aim: The aim of this paper is to describe the ventriculoperitoneal shunt complications in pediatrics patients andto point out the role of nursing stuff in the prevention of them.Methods: This include literature search on the database Medline and relevant with that issue internationalhydrocephalus organizations to identify studies regarding the complications of ventriculoperitoneal shunt and thenursing care for each complication.Results: Ventriculoperitoneal shunt is the treatment of hydrocephalic infants, rather than endoscopic thirdventriculostomy. Although the success of the ventriculoperitoneal shunt’s placement, the patients usually sufferfrom its afterwards complications. The complications involves postoperative shunt infection, shunt placementfailure, shunt obstruction – malfunction, abdominal complications – peritonitis, valve complications, slitventriclesyndrome and seizures. The role of the nursing stuff is vital, particularly in the postoperative weeks.Conclusion: A proper nursing assessment includes valid identification of complications and their prompttreatment. Also, nurses had to implement accurate nursing care, in order to prevent any complication. Finally,parental teaching from the nurses is crucial in the process of health outcomes for pediatric patient.

  6. Hydrocephalus and Ventriculoperitoneal Shunts: Modes of Failure and Opportunities for Improvement.

    Jorgensen, Julianne; Williams, Corin; Sarang-Sieminski, Alisha


    Between 0.5 and 4 of every 1000 children are born with hydrocephalus. Hydrocephalus is an over-accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can affect cognitive function, vision, appetite, and cranial nerve function. Left untreated, hydrocephalus can result in death. The current treatment for hydrocephalus uses ventriculoperitoneal (VP) shunts with valves to redirect CSF from the ventricles into the peritoneum. Shunt technology is limited by a number of complications, which include infection after implantation, shunt obstruction due to clot formation or catheter obstruction by scar tissue or choroid plexus, disconnection and tubing migration, and overdrainage or underdrainage of CSF due to valve malfunction. While modifications to surgical procedures and shunt design have been introduced, only modest improvements in outcomes have been observed. Here we provide an overview of hydrocephalus, VP shunts, and their modes of failure, and we identify numerous areas of opportunity for biomedical engineers and physicians to collaborate to improve the performance of VP shunts.

  7. Congenital extrahepatic portosystemic shunts

    Murray, Conor P.; Yoo, Shi-Joon; Babyn, Paul S. [Department of Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, M5G 1X8, Toronto, Ontario (Canada)


    A congenital extrahepatic portosystemic shunt (CEPS) is uncommon. A type 1 CEPS exists where there is absence of intrahepatic portal venous supply and a type 2 CEPS where this supply is preserved. The diagnosis of congenital portosystemic shunt is important because it may cause hepatic encephalopathy. To describe the clinical and imaging features of three children with CEPS and to review the cases in the published literature. The diagnostic imaging and medical records for three children with CEPS were retrieved and evaluated. An extensive literature search was performed. Including our cases, there are 61 reported cases of CEPS, 39 type 1 and 22 type 2. Type 1 occurs predominantly in females, while type 2 shows no significant sexual preponderance. The age at diagnosis ranges from 31 weeks of intrauterine life to 76 years. Both types of CEPS have a number of associations, the most common being nodular lesions of the liver (n=25), cardiac anomalies (n=19), portosystemic encephalopathy (n=10), polysplenia (n=9), biliary atresia (n=7), skeletal anomalies (n=5), and renal tract anomalies (n=4). MRI is recommended as an important means of diagnosing and classifying cases of CEPS and examining the associated cardiovascular and hepatic abnormalities. Screening for CEPS in patients born with polysplenia is suggested. (orig.)

  8. An electronic circuit for sensing malfunctions in test instrumentation

    Miller, W. M., Jr.


    Monitoring device differentiates between malfunctions occurring in the system undergoing test and malfunctions within the test instrumentation itself. Electronic circuits in the monitor use transistors to commutate silicon controlled rectifiers by removing the drive voltage, display circuits are then used to monitor multiple discrete lines.

  9. Anatomical Closure of Left-to-Right Shunts in Premature Infants with Bronchopulmonary Dysplasia and Pulmonary Hypertension: A Cautionary Tale

    Narendra R. Dereddy


    Full Text Available Closure of a systemic to pulmonary shunt in premature infants with bronchopulmonary dysplasia may be beneficial, but in the presence of pulmonary hypertension is controversial. Here, we discuss two premature infants with pulmonary hypertension who developed acute pulmonary hypertensive crisis after closure of these shunts and hence advise caution.

  10. Control Rod Malfunction at the NRAD Reactor

    Thomas L. Maddock


    The neutron Radiography Reactor (NRAD) is a training, research, and isotope (TRIGA) reactor located at the INL. The reactor is normally shut down by the insertion of three control rods that drop into the core when power is removed from electromagnets. During a routine shutdown, indicator lights on the console showed that one of the control rods was not inserted. It was initially thought that the indicator lights were in error because of a limit switch that was out of adjustment. Through further testing, it was determined that the control rod did not drop when the scram switch was initially pressed. The control rod anomaly led to a six month shutdown of the reactor and an in depth investigation of the reactor protective system. The investigation looked into: scram switch operation, console modifications, and control rod drive mechanisms. A number of latent issues were discovered and corrected during the investigation. The cause of the control rod malfunction was found to be a buildup of corrosion in the control rod drive mechanism. The investigation resulted in modifications to equipment, changes to both operation and maintenance procedures, and additional training. No reoccurrences of the problem have been observed since corrective actions were implemented.

  11. I and C functional test facility malfunction cause and effect

    Kwon, Kee Choon


    The objective of I and C function test facility (FTF) is to validate newly developed digital control and protection algorithm, alarm reduction algorithm and the function of operator support system and so on. To realize transient and accident situation in the FTF, the result of the activation of malfunction should be similar to the situation of real nuclear power plants. In this technical report, describe the Group, Malfunction No., Description, Option, Recommendations, Considered in Subroutine, Limitations, Cause, and Effect of the malfunctions implemented in FTF. (author).

  12. Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in A Child: A Case Report

    Babak ABDINIA


    Full Text Available Brucellosis is an endemic zoonosis in Iran. It is a systemic infection that can involve any organs or systems of the body and have variable presentations. Ventriculoperitoneal (VP shunt infections due to brucellosis have been rarely reported in the literatures.This is the history of a four years old boy who developed Brucella meningoencephalitis at the age of 42 months, whilst he had a VP shunt in situ for hydrocephalus treatment. Also, he presented brucellosis as acute abdomen. This patient was treated with trimethoprim-sulfamethoxazole, gentamicin and rifampicin. The shunt was extracted and all clinical and laboratory test abnormalities subsided through this management.We propose that in a patient with Brucella meningoencephalitis, the cerebrospinal fluid shunt system can be extracted and treatment with appropriate combination of antibiotics could be successful. Moreover, it shows that brucellosis should be considered in the differential diagnosis for acute abdomen and ascites in endemic regions.

  13. A novel method for salvage of malfunctioning peritoneal dialysis catheter

    Ali Akbar Beig


    Conclusions: Comparing the advantages and disadvantages of this method to the previous laparoscopically repaired catheter, we concluded that this new method is efficient, and is a suitable way for malfunctioning PD catheter salvage.

  14. Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

    Bruckheimer, Elchanan, E-mail:; Dagan, Tamir [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel); Atar, Eli; Schwartz, Michael [Schneider Children' s Medical Center Israel, Section of Radiology (Israel); Kachko, Ludmila [Schneider Children' s Medical Center Israel, Section of Anesthesiology (Israel); Superina, Riccardo; Amir, Gabriel [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel); Shapiro, Rivka [Schneider Children' s Medical Center Israel, Section of Gastroenterology (Israel); Birk, Einat [Schneider Children' s Medical Center Israel, Section of Pediatric Cardiology (Israel)


    Purpose: Congenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported. Methods: Pressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18 mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by {approx}50 %. Recatheterization was performed approximately 3 months later. If the portal pressure was below 18 mmHg and vessels had developed, the shunt was closed with a device. Results: Six patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5-13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2-8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7 {+-} 11.3 to 10.8 {+-} 1.8 mmHg; p = 0.016), significant growth of the portal vessels (0.8 {+-} 0.5 to 4.0 {+-} 2.4 mm; p = 0.037), and normalization of ammonia levels (202.1 {+-} 53.6 to 65.7 {+-} 9.6 {mu}mol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia.

  15. Syringosubarachnoid shunting using a myringotomy tube

    Jack M Leschke


    Conclusion: We used a myringotomy tube for syringosubarachnoid shunting for the surgical management of a posttraumatic syrinx with good results. This technique minimizes suturing and may minimize shunt-related complications.

  16. Piezoelectric RL shunt damping of flexible structures

    Høgsberg, Jan Becker; Krenk, Steen


    Resonant RL shunt circuits represent a robust and effective approach to piezoelectric damping, provided that the individual shunt circuit components are calibrated accurately with respect to the dynamic properties of the corresponding flexible structure. The balanced calibration procedure applied...

  17. Shunting ratios for MHD flows

    Birzvalk, Yu.


    The shunting ratio and the local shunting ratio, pertaining to currents induced by a magnetic field in a flow channel, are properly defined and systematically reviewed on the basis of the Lagrange criterion. Their definition is based on the energy balance and related to dimensionless parameters characterizing an MHD flow, these parameters evolving from the Hartmann number and the hydrodynamic Reynolds number as well as the magnetic Reynolds number, and the Lundquist number. These shunting ratios, of current density in the core of a stream (uniform) or equivalent mean current density to the short-circuit (maximum) current density, are given here for a slot channel with nonconducting or conducting walls, for a conduction channel with heavy side rails, and for an MHD-flow around bodies. 5 references, 1 figure.

  18. 采用分流管调整术治疗急性进展的正常颅压脑积水的初步研究%A Preliminary Study for the Treatment of Acute Normal Pressure Hydrocephalus by Shunting Adjustment

    李雄; 赵奇煌; 李锦平


    Objective: Preliminary studies on acute normal pressure hydrocephalus (NPH) in the diagnosis and treatment of patients. Methods:Retrospectively analysis patients data Beijing Chaoyang Hospital between September 2010 to June 2013. eight cases were treated as acute progress NPH , Including 5 males and 3 females, aged 57 to 74 years, mean 65.3 years. All patients were diagnosed with hydrocephalus, six cases were diagnosed with NPH pre-admission, 2 Cases were diagnosed during admission. Patients before admission were undergone ventriculo-peritoneal shunt, of whom six were placed anti-siphon shunt systems regulatorly, two cases were placed normal adjustable shunt systems. Analysis of diagnosis and treatment were performed Results:8 cases of acute progressive NPH patients were performed shunt adjustment. patients were followed up from 3 to 30 months, symptoms were all improved, seven patients returned to normal, one patient was discharged with occasional incontinence and return to normal after follow-up 3 months. Conclusions:acute NPH progression patients who were poor response to pressure revision even to the lowest level , cerebrospinal fluid shunt adjustment surgery means safe and effective .%目的:对急性进展的正常颅压脑积水(NPH)患者的诊断及治疗进行初步研究。方法:回顾性分析2010年9月至2013年6月间北京朝阳医院神经外科收治的8例表现为急性进展NPH患者资料。其中男5例,女3例,年龄57~74岁,平均65.3岁。所有患者术前均诊断为脑积水,6例被诊断为NPH,2例治疗过程中诊断为NPH。患者入院前均行脑室腹腔分流术,其中6例放置可调压抗虹吸分流管,2例放置可调压分流管。分析诊断其要点及治疗经过。结果:8例急性进展NPH患者,行全麻下分流管调整术治疗,均成功救治,术后随访3~30月,患者症状均获得改善,7例患者恢复正常,1例患者出院时候偶有尿失禁,随访3月后恢复正常。结论:急性进展的NPH

  19. Fibrous capsule formation of the peritoneal catheter tip in ventriculoperitoneal shunt: Two case reports

    Tomoaki Kano


    Full Text Available Background: A fibrous capsule formation of a peritoneal catheter tip has not previously been researched as a complication of ventriculoperitoneal (VP shunts. Case Description: Two adult patients who had undergone a VP shunt for communicative hydrocephalus following subarachnoid hemorrhage caused by a ruptured aneurysm have been identified with malfunction of the VP shunt system by mild disturbance of consciousness and gait disturbance or loss of appetite. Hydrocephalus was diagnosed by computed tomography and the obstruction of the peritoneal catheter was revealed by shuntgraphy. Laparoscopy was performed and the peritoneal catheter tips were obstructed by fibrous white capsules that covered them. One was a thin membranous capsule like a stocking with two small endoluminal granulomas of the peritoneal catheter, and other one was a fibrous glossy white capsule like a sock. These fibrous capsules were excised by laparoscopy forceps without the conversion to a new peritoneal catheter. Following the procedure, the shunt functioned normally. The pathological diagnoses were peritoneum with foreign body reaction or hyalinization of membranous tissue surrounded by fibrous tissue. Conclusion: These fibrous capsules might be formed by the peritoneal reaction to cerebrospinal fluid as a foreign material. As such, a periodic medical check should be scheduled since a fibrous capsule of the peritoneal catheter tip might be formed again.

  20. An Intra-Abdominal Pseudocyst around a Ventriculoperitoneal Shunt due to Streptococcus Infection 7 Years after Shunt Surgery

    Arata Tomiyama


    Full Text Available In 1999, a 50-year-old woman underwent ventriculoperitoneal (VP shunt surgery for hydrocephalus after subarachnoid hemorrhage. She was hospitalized for fever and recurrent systemic seizures in November 2006. Head computed tomography (CT showed only old changes. The seizures and fever were controlled by medicinal therapy. However, in December, her consciousness level suddenly decreased, and she showed progressive lower abdominal distension. Head CT showed marked ventriculomegaly, and abdominal CT showed a giant cystic mass at the shunt-tube tip in the lower abdominal cavity. Because thick pus was aspirated from the intra-abdominal mass, we diagnosed the patient with acute obstructive hydrocephalus due to an infected abdominal pseudocyst. Laparotomy and direct cyst drainage were performed, and antibiotic therapy against Streptococcus, the causative pathogen, was administered. The VP shunt tube was replaced. The postoperative course was uneventful, and postoperative CT showed hydrocephalus improvement and no pseudocyst recurrence. Abdominal pseudocysts, which are rare after VP shunt surgeries, usually occur after the subacute postoperative course in younger cerebral hemorrhagic cases. Our case was quite rare because the cyst developed in the chronic phase in an older patient and was caused by streptococcal infection. The cyst components should be examined before cyst drainage when choosing surgical strategies.

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... encourage linking to this site. × Recommend RadiologyInfo to a friend Send to (friend's e-mail address): From ( ...

  2. The capacity of associative memories with malfunctioning neurons.

    Shirazi, M N; Maekawa, S


    Hopfield associative memories with alphan malfunctioning neurons are considered. Using some facts from exchangeable events theory, the asymptotic storage capacity of such a network is derived as a function of the parameter alpha under stability and attractivity requirements. It is shown that the asymptotic storage capacity is (1-alpha)(2)/n(4 log n) under stability and (1-alpha)(2)(1-2rho)(2)n/(4 log n) under attractivity requirements, respectively. Comparing these capacities with their maximum values corresponding to the case when there is no malfunctioning neurons, alpha=0, shows the robustness of the retrieval mechanism of Hopfield associative memories with respect to the existence of malfunctioning neurons. This result also supports the claim that neural networks are fault tolerant.

  3. Impact of External Ventricular Drainage Volumes on Shunt Dependency after Subarachnoid Hemorrhage.

    Hayek, Muhammad Ali; Roth, Christian; Kaestner, Stefanie; Deinsberger, Wolfgang


    Background The indication for and the timing of a permanent shunt operation in patients following acute hydrocephalus (HC) after subarachnoid hemorrhage (SAH) remains controversial because risk factors for chronic HC fail to predict permanent shunt dependency. The amount of cerebrospinal fluid (CSF) drained via an external ventricular drain (EVD) may predict shunt dependency. Methods We conducted a retrospective study of our HC database from January 2006 to December 2011. All patients receiving an EVD due to acute HC after SAH were analyzed. The daily amount of drained CSF was documented until the EVD was removed or converted to a permanent shunt either immediately or during a follow-up period of 6 months. Results A total of 139 patients (48 male, 91 female; mean age: 57 ± 14 years) were eligible for the study. Mean duration of EVD was 16 ± 10 days (range: 4-60 days). A permanent shunt was necessary in 32% of cases (n = 45). The mean daily CSF volume was 139 ± 17 mL (range: 15-460 mL). Using repeated-measures analysis of variance, there was a significant difference of daily drained CSF volumes between both the groups in the first 15 days after the EVD. Conclusion Our results suggest that the daily amount of external CSF drainage volume in the acute state of SAH might influence the development of HC.

  4. Ventriculopleural shunting with new technology valves.

    Martínez-Lage, J F; Torres, J; Campillo, H; Sanchez-del-Rincón, I; Bueno, F; Zambudio, G; Poza, M


    Ventriculoperitoneal shunting constitutes the standard procedure for draining cerebrospinal fluid (CSF) in children with hydrocephalus. Ventriculoatrial and ventriculopleural shunting are alternative methods of CSF drainage, which have gained less acceptance. Ventriculopleural shunts are seldom used owing to justified fears of pneumothorax and symptomatic effusions of CSF. The addition of an antisiphon device to standard shunt systems seems to have prevented CSF pleural effusion. From 1988 to 1998, we treated each of six hydrocephalic children with a ventriculopleural shunt. In five cases we used new-technology valves designed to prevent the effects of siphoning with current differential pressure valves. Peritoneal adhesions, recent peritonitis, ascites, and obstruction of a previous ventriculoatrial shunt were the indications for pleural shunting. After a mean follow-up period of 2.5 years all shunts were functioning adequately. Only one patient showed transient symptoms of CSF overdrainage, which were corrected by up-grading the valve setting with the magnet. A late death was unrelated to the pleural shunting procedure. The use of valves of a new design designed to prevent overdrainage seems to account for the satisfactory outcomes observed in this series. We suggest that ventriculopleural shunting should be considered as the preferred alternative to peritoneal drainage in children with intra-abdominal adhesions or with a history of recent peritoneal infection.

  5. A wireless monitoring system for Hydrocephalus shunts.

    Narayanaswamy, A; Nourani, M; Tamil, L; Bianco, S


    Patients with Hydrocephalus are usually treated by diverting the excess Cerebrospinal Fluid (CSF) to other parts of the body using shunts. More than 40 percentage of shunts implanted fail within the first two years. Obstruction in the shunts is one of the major causes of failure (45 percent) and the detection of obstruction reduces the complexity of the revision surgery. This paper describes a proposed wireless monitoring system for clog detection and flow measurement in shunts. A prototype was built using multiple pressure sensors along the shunt catheters for sensing the location of clog and flow rate. Regular monitoring of flow rates can be used to adjust the valve in the shunt to prevent over drainage or under drainage of CSF. The accuracy of the flow measurement is more than 90 percent.

  6. Right Lower Quadrant Abdominal Pain in a Patient with Prior Ventriculoperitoneal Shunting: Consider the Tip!

    Petros Charalampoudis


    Full Text Available Introduction. Ventriculoperitoneal (VP shunting is the treatment of choice for nonobstructive hydrocephalus. In patients with such a device, right lower quadrant abdominal pain can puzzle the surgeon, posing a differential diagnostic problem among appendicitis, nonsurgical colicky pain, and primary shunt catheter tip infection. Treatment is different in either case. Presentation of Case. We hereby present a case of a young woman with prior ventriculoperitoneal shunt positioning who presented to our department with right lower quadrant abdominal pain. The patient underwent a 24-hour observation including a neurosurgery consult in order to exclude acute appendicitis and VP shunt tip infection. Twenty four hours later, the patient’s symptomatology improved, and she was discharged with the diagnosis of atypical colicky abdominal pain seeking a gastroenterologist consult. Discussion. This case supports that when a patient with prior VP shunting presents with right lower quadrant abdominal pain, differential diagnosis can be tricky for the surgeon. Conclusion. Apart from acute appendicitis, primary or secondary VP catheter tip infection must be considered because the latter can be disastrous.

  7. 30 CFR 75.352 - Actions in response to AMS malfunction, alert, or alarm signals.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Actions in response to AMS malfunction, alert... § 75.352 Actions in response to AMS malfunction, alert, or alarm signals. (a) When a malfunction, alert... be identified and the AMS operator must promptly notify appropriate personnel. (b) Upon...

  8. Identification of Safety System Malfunction Using Correlation Visualization

    Park, Suk Young; Heo, Gyun Young [Kyung Hee University, Yongin (Korea, Republic of); Kim, Jung Taek [KAERI, Dajeon (Korea, Republic of)


    I and C systems should provide the reliable information particularly when an accident occurs and operators should also take action to mitigate the accident by identifying the cause of accident. However, incorrect information might be provided due to malfunction or failure of safety system caused by an accident. Accordingly, operators get confused and it made difficult for them to take appropriate actions. If they fail to grasp the exact information of progress then it might lead to spread of accident. Thus, we propose the idea that enables to identify safety system malfunctions or failures in such environment impossible to guarantee of safety system. For identifying the malfunctions or failures of a safety system, the correlation visualization which shows linear relationship between parameters is performed. The correlation visualization results show different images with various scenarios, so it determines which system has problem to operate. Therefore we can identify the safety system operability by the comparison of the correlation visualization results. Furthermore, we can determine specifically which parameter shows abnormal signal using correlation visualization after identifying the operability of safety system. The methodology can determine the situation by viewing the overall signals and include the result robustly though incorrect signal input to the indictor. Proposed methodology is demonstrated through case study by specifying SBLOCA as an initiating event that is judged greater contribution of severe accident. Various accident data are obtained according to operability of safety system and confirmed a feasibility of idea by applying to case study. Overall reliability of I and C system can be improved using suggested methodology. As a result, this research can be helpful in accident response and management if safety system malfunctioned when an accident occurred.

  9. Congenital Portosystemic Shunt: Our Experience

    Tiziana Timpanaro


    Full Text Available Introduction. Congenital portosystemic venous malformations are rare abnormalities in which the portal blood drains into a systemic vein and which are characterized by extreme clinical variability. Case Presentations. The authors present two case reports of a congenital extrahepatic portosystemic shunt (Type II. In the first patient, apparently nonspecific symptoms, such as headache and fatigue, proved to be secondary to hypoglycemic episodes related to the presence of a portosystemic shunt, later confirmed on imaging. During portal vein angiography, endovascular embolization of the portocaval fistula achieved occlusion of the anomalous venous tract. In the second patient, affected by Down’s syndrome, the diagnosis of a portosystemic malformation was made by routine ultrasonography, performed to rule out concurrent congenital anomalies. Because of the absence of symptoms, we chose to observe this patient. Conclusions. These two case reports demonstrate the clinical heterogeneity of this malformation and the need for a multidisciplinary approach. As part of a proper workup, clinical evaluation must always be followed by radiographic diagnosis.

  10. Preoperative shunts in thalamic tumours.

    Goel A


    Full Text Available Thirty one patients with thalamic glioma underwent a pre-tumour resection shunt surgery. The procedure was uneventful in 23 patients with relief from symptoms of increased intracranial pressure. Eight patients worsened after the procedure. The level of sensorium worsened from excessively drowsy state to unconsciousness in seven patients. Three patients developed hemiparesis, 4 developed paresis of extra-ocular muscles and altered pupillary reflexes, and 1 developed incontinence of urine and persistent vomiting. Alteration in the delicately balanced intracranial pressure and movements in the tumour and vital adjacent brain areas could be the probable cause of the worsening in the neurological state in these 8 patients. On the basis of these observations and on review of literature, it is postulated that the ventricular dilatation following an obstruction in the path of the cerebrospinal fluid flow by a tumour could be a natural defense phenomenon of the brain.

  11. CSF ascites : a rare complication of ventriculoperitoneal shunt surgery.

    Chidambaram B


    Full Text Available CSF ascites is a very rare complication of ventriculoperitoneal (VP shunt procedure. No definite explanation has been offered for the inability of the peritoneum to absorb the CSF. Two children who underwent VP shunting for hydrocephalus, presented with ascites 3 (1/2 years and 4 months respectively, after the shunt was placed. The treatment of choice is conversion of the VP shunt to a ventriculoatrial shunt.

  12. Malfunctioning central venous catheters in children: a diagnostic approach

    Barnacle, Alex; Arthurs, Owen J.; Roebuck, Derek; Hiorns, Melanie P. [Great Ormond Street Hospital, Radiology Department, London (United Kingdom)


    Central venous access is increasingly becoming the domain of the radiologist, both in terms of the insertion of central venous catheters (CVCs) and in the subsequent management of these lines. This article seeks to provide an overview of the CVC types available for paediatric patients and a more detailed explanation of the spectrum of complications that may lead to catheter malfunction. A standard catheter contrast study or 'linogram' technique is described. The normal appearances of such a study and a detailed pictorial review of abnormal catheter studies are provided, together with a brief overview of how information from catheter investigations can guide the management of catheter complications. (orig.)

  13. Idiopathic intracranial hypertension: lumboperitoneal shunts versus ventriculoperitoneal shunts--case series and literature review.

    Abubaker, Khalid


    OBJECTIVES: Idiopathic intracranial hypertension (IIH) is an uncommon but important cause of headache that can lead to visual loss. This study was undertaken to review our experience in the treatment of IIH by neuronavigation-assisted ventriculoperitoneal (VP) shunts with programmable valves as compared to lumboperitoneal (LP) shunts. METHODS: A retrospective chart review was conducted on 25 patients treated for IIH between 2001 and 2009. Age, sex, clinical presentation, methods of treatment and failure rates were recorded. RESULTS: Seventy-two per cent were treated initially with LP shunts. Failure rate was 11% in this group. Neuronavigation-assisted VP shunts were used to treat 28%. In this group, the failure rate was 14%. CONCLUSION: Our experience indicates that both LP shunts and VP shuts are effective in controlling all the clinical manifestations of IIH in the immediate postoperative period. Failure rates are slightly higher for VP shunts (14%) than LP shunts (11%). However, revision rates are higher with LP shunts (60%) than with VP shunts (30%).

  14. Congenital portosystemic shunts with and without gastrointestinal bleeding - case series

    Gong, Ying; Chen, Jun; Chen, Qi; Ji, Min; Pa, Mier; Qiao, Zhongwei [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Zhu, Hui [Fudan University Shanghai Cancer Center, Department of Radiology, Shanghai (China); Zheng, Shan [Children' s Hospital of Fudan University, Department of Surgery, Shanghai (China)


    The clinical presentation of congenital portosystemic shunt is variable and gastrointestinal bleeding is an uncommon presentation. To describe the imaging features of congenital portosystemic shunt as it presented in 11 children with (n = 6) and without gastrointestinal bleeding (n = 5). We performed a retrospective study on a clinical and imaging dataset of 11 children diagnosed with congenital portosystemic shunt. A total of 11 children with congenital portosystemic shunt were included in this study, 7 with extrahepatic portosystemic shunts and 4 with intrahepatic portosystemic shunts. Six patients with gastrointestinal bleeding had an extrahepatic portosystemic shunt, and the imaging results showed that the shunts originated from the splenomesenteric junction (n = 5) or splenic vein (n = 1) and connected to the internal iliac vein. Among the five cases of congenital portosystemic shunt without gastrointestinal bleeding, one case was an extrahepatic portosystemic shunt and the other four were intrahepatic portosystemic shunts. Most congenital portosystemic shunt patients with gastrointestinal bleeding had a shunt that drained portal blood into the iliac vein via an inferior mesenteric vein. This type of shunt was uncommon, but the concomitant rate of gastrointestinal bleeding with this type of shunt was high. (orig.)

  15. Resonant Electromagnetic Shunt Damping of Flexible Structures

    Høgsberg, Jan Becker


    Electromagnetic transducers convert mechanical energy to electrical energy and vice versa. Effective passive vibration damping of flexible structures can therefore be introduced by shunting with an accurately calibrated resonant electrical network thatcontains a capacitor to create the desired...

  16. Temporary intravascular shunts for peripheral vascular trauma.

    Husain A


    Full Text Available Polyvinylchloride (PVC disposable endotracheal suction catheters were successfully used as temporary intravascular shunts in 5 patients of popliteal artery trauma. These simple shunts should be used routinely in such conditions to immediately re-establish blood supply to the ischaemic limb particularly in patients of polytrauma where systemic anticoagulation is contraindicated. This avoids the inherent delay prior to vascular repair and reduces the incidence of irreversible ischemia.

  17. Syringoperitoneal shunt - a promising treatment in syringomyelia

    Wester, K.; Midgard, R.; Kjosavik, I.F.


    Five patients with radiologically relatively pronounced multicystic syringomyelia were operated with an open, non-valved syringoperitoneal shunt. In the postoperative MRI scans there was an immediate and pronounced reduction of all cystic compartments, and within a few months the cysts had virtually disappeared. Two of the patients experienced marked neurological improvement. In one patient the shunt procedure led to additional moderate neurological deficits caused by postoperative rotation of the intrameduallary T-drain. For this reason straight intramedullary drains are now used.

  18. Aneurysmal portosystemic venous shunt: a case report.

    Bodner, G; Glück, A; Springer, P; König, P; Perkmann, R


    A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

  19. Simulation of Malfunctions for the ISS Double-Gimbal Control Moment Gyroscope

    Inampudi, Ravi; Gordeuk, John


    This paper presents a simplified approach to simulation of malfunctions of the Control Moment Gyroscope (CMG) on board the International Space Station (ISS). These malfunctions will be used as part of flight training of CMG failure scenarios in the guidance navigation control (GNC) subsystem of the Training Systems for 21st Century (TS21) simulator. The CMG malfunctions are grouped under mechanical, thermal and electrical categories. A malfunction can be as simple as one which only affects the telemetry or a complex one that changes the state and behavior of the CMG model. In both cases, the ISS GNC flight software will read the telemetry and respond accordingly. The user executes these malfunctions by supplying conditional data which modify internal model states and then elicit a response as seen on the user displays. Ground operators and crew on board the ISS use CMG malfunction procedures to better understand and respond to anomalies observed within the CMG subsystem.

  20. Cell shunt resistance and photovoltaic module performance

    McMahon, T.J.; Basso, T.S.; Rummel, S.R. [National Renewable Energy Lab., Golden, CO (United States)


    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  1. Ventriculoperitoneal shunt in cryptococcal meningitis with hydrocephalus.

    Tang, L M


    Fourteen patients with cryptococcal meningitis were reviewed. All patients had a ventriculoperitoneal shunt for hydrocephalus. Early recognitions and prompt relief of hydrocephalus were useful for eight patients who showed rapid deterioration of consciousness or signs of cerebral herniation. There was no surgical response in four patients who had had weeks of confusion or mental change. It seems, therefore, that the duration of disturbance of consciousness or change of mentality before shunting is critical in determination of the outcome of the treatment. Ventricular shunting was effective in relieving papilledema in five patients. However, the surgery did not prevent the development of papilledema to optic atrophy and subsequent blindness in two patients. Hence, in addition to hydrocephalus with increased intracranial pressure, conditions such as direct invasion of the optic pathways by Cryptococcus neoformans or optochiasmatic arachnoiditis may be responsible for the visual failure. Ventricular shunting was also helpful in restoring paraparesis in one patient. Of the cerebrospinal fluid determinations, low protein concentration was a favorable indicator for surgery. Of the seven patients who received the surgical procedure before the start of antifungal therapy, four showed a significant improvement despite active infection of the central nervous system. None of the seven patients deteriorated because of the surgical operation. Thus, active stage of cryptococcal meningitis does not contraindicate the necessity of shunting, and premedication with antifungal drugs is unnecessary. Also, no shunt-related morbidity and mortality was seen in this study.

  2. Malfunction analysis of OPGW of stainless steel-unit structure

    李星梅; 张素芳; 王旭锋; 乞建勋


    Composite fiber optic overhead ground wire (OPGW) is increasingly applied in China’s overhead transmission lines. The stainless steel structure is adopted by most OPGWs as it is very small and easy to match the existing ground wire. The malfunction of OPGW in Beijing-Shanghai Optical Communication Project was analyzed through the chemical composition method and spectrum semi-quantitative method. The analysis indicates that the cable fault was due to the failure of seepage and irregular holes in the steel pipe of the optical unit. The rain water and the watery air entered into the optical units, and the water in turn became ice when temperature dropped. The occurrence of ice led to the acceleration of attenuation of the fiber. The results show that the rupture of stainless steel tube is mainly due to the instability of welding technique. The malfunction of OPGW is due to the local defects of welding seam because of local stress concentration in the manufacturing process.

  3. Comparative study of lumboperitoneal shunt versus ventriculoperitoneal shunt in post meningitis communicating hydrocephalus in children

    Amit Singh


    Full Text Available Background: Managing post meningitis hydrocephalus in children is a herculean task for the treating pediatric surgeon or neurosurgeon because of the morbidity associated with the disease per se and the complications of shunt surgery. By this study, the effectiveness of lumboperitoneal (LP shunt and ventriculoperitoneal (VP shunt in cases of post meningitis communicating hydrocephalus was assessed in children. Materials and Methods: This was a retrospective analysis of the records of children admitted in our institute between December 2005 and March 2008. Only children with post meningitis communicating hydrocephalus who underwent either LP or VP with a minimum follow-up period of 36 months were included in the study. Children with non-communicating hydrocephalus or hydrocephalus due to another etiology were excluded. Investigations were included plain brain computed tomography scan, air encephalography and X-ray skull. Medium pressure Chabbra shunt with slit valves was used in all cases of VP and LP shunt. A comparative analysis of the outcome was carried out between the two groups. Results: There were 66 males and 24 females (M: F 2.7:1. The average age at presentation was 40.3 months. LP shunt was performed in 37 while VP shunt in 53 cases Complication rate in the LP and VP shunt was 15% and 29% respectively with non-obstructed complications higher in VP group when compared to LP group. Obstructed complication rate was similar in both groups. Conclusion: Due to less morbidity and ease of placement, LP shunt can be an alternative to VP shunt in cases of communicating hydrocephalus in children, which has more non-obstructed complication rates as compared to LP shunt.

  4. Idiopathic intracranial hypertension: lumboperitoneal shunts versus ventriculoperitoneal shunts--case series and literature review.

    Abubaker, Khalid


    Idiopathic intracranial hypertension (IIH) is an uncommon but important cause of headache that can lead to visual loss. This study was undertaken to review our experience in the treatment of IIH by neuronavigation-assisted ventriculoperitoneal (VP) shunts with programmable valves as compared to lumboperitoneal (LP) shunts.

  5. Noncavernous arteriovenous shunts mimicking carotid cavernous fistulae

    Kobkitsuksakul, Chai; Jiarakongmun, Pakorn; Chanthanaphak, Ekachat; Singhara Na Ayudya, Sirintara (Pongpech)


    PURPOSE The classic symptoms and signs of carotid cavernous sinus fistula or cavernous sinus dural arteriovenous fistula (AVF) consist of eye redness, exophthalmos, and gaze abnormality. The angiography findings typically consist of arteriovenous shunt at cavernous sinus with ophthalmic venous drainage with or without cortical venous reflux. In rare circumstances, the shunts are localized outside the cavernous sinus, but mimic symptoms and radiography of the cavernous shunt. We would like to present the other locations of the arteriovenous shunt, which mimic the clinical presentation of carotid cavernous fistulae, and analyze venous drainages. METHODS We retrospectively examined the records of 350 patients who were given provisional diagnoses of carotid cavernous sinus fistulae or cavernous sinus dural AVF in the division of Interventional Neuroradiology, Ramathibodi Hospital, Bangkok between 2008 and 2014. Any patient with cavernous arteriovenous shunt was excluded. RESULTS Of those 350 patients, 10 patients (2.85%) were identified as having noncavernous sinus AVF. The angiographic diagnoses consisted of three anterior condylar (hypoglossal) dural AVF, two traumatic middle meningeal AVF, one lesser sphenoid wing dural AVF, one vertebro-vertebral fistula (VVF), one intraorbital AVF, one direct dural artery to cortical vein dural AVF, and one transverse-sigmoid dural AVF. Six cases (60%) were found to have venous efferent obstruction. CONCLUSION Arteriovenous shunts mimicking the cavernous AVF are rare, with a prevalence of only 2.85% in this series. The clinical presentation mainly depends on venous outflow. The venous outlet of the arteriovenous shunts is influenced by venous afferent-efferent patterns according to the venous anatomy of the central nervous system and the skull base, as well as by architectural disturbance, specifically, obstruction of the venous outflow. PMID:27767958

  6. Ventriculoperitoneal shunt migration and coiling: A report of two cases

    Shahram Shahsavaran


    Full Text Available Migration of the proximal and distal catheters of the ventriculoperitoneal shunt is a very rare event. Here, we report two infants with hydrocephalus and ventriculoperitoneal shunt who presented later with shunt coiling and migration. The first infant was admitted with scalp swelling around proximal incision 3 months after shunt insertion and migration and coiling of both ventricular and peritoneal catheters occurred under the scalp at that point. The second patient was referred 1 month after shunting with tense fontanel and vomiting. New brain imaging confirmed the whole shunt inside both lateral ventricles. The possible mechanisms causing this very uncommon complication and the management are explained.

  7. Simulation model for port shunting yards

    Rusca, A.; Popa, M.; Rosca, E.; Rosca, M.; Dragu, V.; Rusca, F.


    Sea ports are important nodes in the supply chain, joining two high capacity transport modes: rail and maritime transport. The huge cargo flows transiting port requires high capacity construction and installation such as berths, large capacity cranes, respectively shunting yards. However, the port shunting yards specificity raises several problems such as: limited access since these are terminus stations for rail network, the in-output of large transit flows of cargo relatively to the scarcity of the departure/arrival of a ship, as well as limited land availability for implementing solutions to serve these flows. It is necessary to identify technological solutions that lead to an answer to these problems. The paper proposed a simulation model developed with ARENA computer simulation software suitable for shunting yards which serve sea ports with access to the rail network. Are investigates the principal aspects of shunting yards and adequate measures to increase their transit capacity. The operation capacity for shunting yards sub-system is assessed taking in consideration the required operating standards and the measure of performance (e.g. waiting time for freight wagons, number of railway line in station, storage area, etc.) of the railway station are computed. The conclusion and results, drawn from simulation, help transports and logistics specialists to test the proposals for improving the port management.

  8. Malfunction of the inner ear is the most frequent cause of dizziness

    Klokker, Mads; Vesterhauge, Søren


    Half of all dizziness patients suffer from a malfunction of the inner ear and benign paroxysmal positional vertigo causes 25-30% of these malfunctions. During the latest two decades new vestibular test equipment has been developed and has made it possible to refine the vestibular diagnoses...

  9. Value of PaO2/FiO2 in Reflecting the Intrapulmonary Shunting of Acute Respiratory Distress Syndrome.%氧合指数对急性呼吸窘迫综合征肺内分流的判定价值

    胡伟航; 刘长文; 胡炜; 陆骏; 郑永科; 朱克毅; 朱英; 王剑荣


    Objective To study how did the accuracy of the oxygenation index ( PaO2/FiO2) reflecting the intrapulmonary shunting (Qsp/Qt) of acute respiratory distress syndrome reduce. Methods Twelve patients who had ARDS were recruited to the study. All required mechanical ventilation,which used lung ventilation protective strategy (Vt6ml/kg) ,and had a Swan - Canz catheter. Then, P - V curves were determined by low - flow method. Subsequently, the parameters of respiratory mechanics and haemodynamics and the blood gas analysis results of periphery and pulmonary artery blood samples were recorded when the conditions of positive end expiratory pressure changed. PaO2/FiO2 and Qsp/Qt were respectively calculated through special formula. Finialy, all data were progressed regression analysis. Results (T)There was linear correlation between Qsp/Qt and PaO2/FiO2, and the coefficient of determination ( R square) was 0.432 which was significantly smaller (P<0.01). ?The multiple regression equation of Qsp/Qt( % ) was y =56.542 -3.371x1 -0.056x2 + 0. 594x3 +2.84x4,in which x1was PaO2/FiO2 ,x2 was haemoglobin, x,was pulmonary wedge pressure, x4was cardiac index,and the adjusted R square was 0. 538(P < 0. 01) . Conclusion The accuracy of the intrapulmonary shunting of acute respiratory distress syndrome simply estimated by PaO2/FiO2 further dropped,because r2 was only 0.432 and Qsp/Qt was simultaneously affected by haemoglobin, pulmonary wedge pressure and cardiac index.%目的 Qt和PaO2/FiO2,对结果进行回归分析.结果 ①Qsp/Qt和PaO2/FiO2两者之间存在线性相关,但决定系数r2只有0.432,相关性偏小;②Qsp/Qt(%)的多元回归方程:y=56.542-3.371x1-0.056x2+0.594x3+2.84x4,x1为PaO2/FiO2,x2为Hgb,x,为PAWP,x4为CI,校正r2 =0.538,(P<0.01).结论 用PaO2/FiO2测算ARDS的Qsp/Qt精确度下降,决定系数r2只有0.432,Qsp/Qt除外PaO2/FiO2还受Hgb、肺动脉楔压(plumonary artery wedge pressure,PAWP)及心脏指数(cardiac index,CI)等影响.

  10. [Temporary vascular shunt technique for resource scarce environments].

    Ouattara, N; Mlynski, A; Pierret, C


    The purpose of this report is to describe a simple and reproducible technique for temporary vascular shunting. This technique is appropriate only for exceptional situations involving scant resource availability. It is not intended to replace conventional vascular shunting techniques.

  11. Delayed otogenic pneumocephalus complicating ventriculoperitoneal shunt

    Francesco Pieri


    Full Text Available Tension pneumocephalus complicating ventriculoperitoneal shunt is extremely rare. We report an elderly male who developed delayed tension pneumocephalus 12 months after ventriculoperitoneal shunt for hydrocephalus complicating aneurysmal subarachnoid hemorrhage. Fine-cut reformatted computer tomography scan revealed a large pneumatocele on the petrous apex associated with tegmen tympani defect. The shunt valve pressure was temporarily raised from 120 mm H 2 O to 200 mm H 2 O, and the patient underwent successful subtemporal extradural repair of the bony defect in the temporal bone. Although extremely rare, otogenic tension pneumocephalus is a potentially life-threatening condition, and urgent surgical repair of the bony defect in the temporal bone reduces the risk of both the morbidity and mortality.

  12. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt

    Ma, Li; Chen, Yi-Li; Yang, Shu-Xu; Wang, Yi-Rong


    Abstract The ventriculoperitoneal (VP) shunt is a routine procedure for cerebrospinal fluid (CSF) diversion, and is associated with many complications. A delayed hemorrhage after the VP shunt surgery, however, is quite rare. In this study, we report a case involving late-onset hemorrhage. The 67-year-old male patient with a history of head trauma and brain surgery underwent a VP shunt placement for hydrocephalus. The surgery course was uneventful and no bleeding was revealed in the first computed tomographic (CT) scan after the procedure. However, a massive intraparenchymal and intraventricular hemorrhage occurred 8 h following adjustment of the valve system on the 8th day after surgery. Erosion of the vasculature by catheter cannulation and a sudden reduction of CSF pressure after downregulation of the valve could be one of the possible causes of the intracerebral hemorrhage (ICH). PMID:26632700

  13. Shunt Active Filter in Damping Harmonics Propagation



    Full Text Available This paper deals with a hybrid shunt active power filter applied on 500 kV HVDC, after a description of the causes and effects harmonic pollution which may damage equipments and interrupt electric power customers service; in this paper we present the deferent solutions of this problem among one has to study the two most recent types of filtering: passive and hybrid filter. The hybrid filter consists of active filter connected in shunt with passive filter. The hybrid shunt active filter proposed is based on three levels PWM inverter and characterized by detecting the harmonic current flowing into the passive filter and controlled by notch algorithm. This structure has been applied on a test HVDC power system, is presented as a technical solution makes it possible to eliminate the disadvantages from passive filtering, and also economic price of active filtering part. The simulation results justified the effectiveness of this type of filter face of the classic passive filter.

  14. Distal splenorenal shunt with partial spleen resection

    Gajin Predrag


    Full Text Available Introduction: Hypersplenism is a common complication of portal hypertension. Cytopenia in hypersplenism is predominantly caused by splenomegaly. Distal splenorenal shunt (Warren with partial spleen resection is an original surgical technique that regulates cytopenia by reduction of the enlarged spleen. Objective. The aim of our study was to present the advantages of distal splenorenal shunt (Warren with partial spleen resection comparing morbidity and mortality in a group of patients treated by distal splenorenal shunt with partial spleen resection with a group of patients treated only by a distal splenorenal shunt. Method. From 1995 to 2003, 41 patients with portal hypertension were surgically treated due to hypersplenism and oesophageal varices. The first group consisted of 20 patients (11 male, mean age 42.3 years who were treated by distal splenorenal shunt with partial spleen resection. The second group consisted of 21 patients (13 male, mean age 49.4 years that were treated by distal splenorenal shunt only. All patients underwent endoscopy and assessment of oesophageal varices. The size of the spleen was evaluated by ultrasound, CT or by scintigraphy. Angiography was performed in all patients. The platelet and white blood cell count and haemoglobin level were registered. Postoperatively, we noted blood transfusion, complications and total hospital stay. Follow-up period was 12 months, with first checkup after one month. Results In the first group, only one patient had splenomegaly postoperatively (5%, while in the second group there were 13 patients with splenomegaly (68%. Before surgery, the mean platelet count in the first group was 51.6±18.3x109/l, to 118.6±25.4x109/l postoperatively. The mean platelet count in the second group was 67.6±22.8x109/l, to 87.8±32.1x109/l postoperatively. Concerning postoperative splenomegaly, statistically significant difference was noted between the first and the second group (p<0.05. Comparing the

  15. Round worm migration along ventriculoperitoneal shunt tract: a rare complication.

    Agarwal P


    Full Text Available Though a ventriculoperitoneal shunt has been associated with myriads of unusual complications, so has been that with roundworms. A case of a three-year-old boy is presented who had an unusual complication of roundworm migration along the shunt tract that presented as shunt tract infection.

  16. Subacute bacterial endocarditis and subsequent shunt nephritis from ventriculoatrial shunting 14 years after shunt implantation

    Burström, Gustav; Andresen, Morten; Bartek, Jiri Jr.


    of inconclusive multidisciplinary investigations, the patient progressed into end-stage renal disease before an echocardiogram revealed a vegetative plaque on the tendinous chords of the tricuspid valve. CSF cultures were grown from the shunt valve, confirming bacterial growth of Propionibacterium acnes suspected...

  17. Laparoscopy versus mini-laparotomy peritoneal catheter insertion of ventriculoperitoneal shunts: a systematic review and meta-analysis.

    He, Mingliang; Ouyang, Leping; Wang, Shengwen; Zheng, Meiguang; Liu, Anmin


    OBJECTIVE Ventriculoperitoneal (VP) shunt treatment is the main treatment method for hydrocephalus. The traditional operative approach for peritoneal catheter insertion is mini-laparotomy. In recent years, laparoscopy-assisted insertion has become increasingly popular. It seems likely that use of an endoscope could lower the incidence of shunt malfunction. However, there is no consensus about the benefits of laparoscopy-assisted peritoneal catheter insertion. METHODS A systematic search was performed using the PubMed, Embase, ScienceDirect, and Cochrane Library databases. A manual search for reference lists was conducted. The protocol was prepared according to the interventional systematic reviews of the Cochrane Handbook, and the article was written on the basis of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. RESULTS Eleven observational trials and 2 randomized controlled trials were included. Seven operation-related outcome measures were analyzed, and 3 of these showed no difference between operative techniques. The results of the meta-analysis are as follows: in the laparoscopy group, the rate of distal shunt failure was lower (OR 0.41, 95% CI 0.25-0.67; p = 0.0003), the absolute effect is 7.11% for distal shunt failure, the number needed to treat is 14 (95% CI 8-23), operative time was shorter (mean difference [MD], -12.84; 95% CI -20.68 to -5.00; p = 0.001), and blood loss was less (MD -9.93, 95% CI -17.56 to -2.31; p = 0.01). In addition, a borderline statistically significant difference tending to laparoscopic technique was observed in terms of hospital stay (MD -1.77, 95% CI -3.67 to 0.13; p = 0.07). CONCLUSIONS To some extent, a laparoscopic insertion technique could yield a better prognosis, mainly because it is associated with a lower distal failure rate and shorter operative time, which would be clinically relevant.

  18. Laparoscopic management of complicated ventriculoperitoneal shunts

    Jain S


    Full Text Available Intra-abdominal migration of the catheter and formation of a cerebrospinal fluid pseudocyst are both rare complications of a ventriculoperitoneal shunt. Traditionally, each condition is treated by a formal laparotomy. Laparoscopic management of the complications in two patients is described.




    A compact three-stage shunt valve system (Orbis SigmaTM Valve) which operates as a flow regulator within certain differential pressure values has been clinically evaluated in the treatment of hydrocephalus. Clinical trials were performed in 134 cases, covering 128 patients aged from 1 day to 79 year

  20. Treatment of syringomyelia with a syringosubarachnoid shunt.

    Tator, C H; Briceno, C


    The surgical results in 40 patients with syringomyelia, treated with a syringosubarachnoid shunt or other procedures are reviewed. The principal indication for surgery was that of significant neurological deterioration. There were 12 patients with idiopathic syringomyelia without tonsillar ectopia, 12 with an associated Chiari malformation, 11 with post-traumatic syringomyelia and five patients with spinal arachnoiditis. There were 38 syringosubarachnoid shunts performed in 35 patients, and an excellent or good result was achieved in 26 patients (74.3%). In terms of the type of syringomyelia, the best results were obtained in the idiopathic group without tonsillar ectopia and in the post-traumatic group. A short duration of pre-operative symptoms favoured a better outcome, and in our opinion, early surgical treatment is indicated for all patients with neurological deterioration. All eight patients in whom a posterior fossa decompression was performed as the initial surgical procedure required a second operation, either a syringosubarachnoid or syringoperitoneal shunt to achieve neurological improvement or stabilization. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for patients with syringomyelia, particularly for the idiopathic and post-traumatic groups. More than one surgical procedure may be required to achieve cessation of deterioration. Overall, excellent or good results were achieved in 29 (72.5%) of the 40 patients.

  1. Therapeutic Characteristic of Acute Myocardial Infarction Complicated by Syndrome of Multi-organ Malfunction with Traditional Chinese Medicine%急性心肌梗死并发多脏器功能失常综合征的中医证治特点



    急性心肌梗死(acute myocardial infarction,AMI)并发多脏器功能失常综合征(multiple organ dysfunction syndrome,MODS)是AMI的危重症,治疗难度大,病死率高达36.9%,病死率与脏器衰竭数呈正相关。多系统功能衰竭(multiple organ failure,MSOF)患者80%合并弥漫性血管内凝血(disseminated intravascular coagulation,DIC),其病死率约为60%。大量、

  2. Malfunction Rates of Bird Flight Diverters on Powerlines in the Mongolian Gobi

    Batsuuri Dashnyam


    Full Text Available The Oyu Tolgoi (OT project, one of the world’s largest copper and gold mines, is located in Gobi Desert of Mongolia. To help meet its target of Net Positive Impact on key biodiversity features such as the Houbara bustard (Chlamydotis undulata the OT installed bird fl ight diverters (BFDs include spiral and fl apper devices to its power transmission lines to reduce the risk of birds hitting the wires. Despite the many studies demonstrating that BFDs reduce collision rates, we could fi nd no published information on malfunction rates of BFDs. In January 2013, we surveyed the physical function of 1,200 BFDs (e.g. 600 fl appers and 600 spirals in three sample areas on each of four lines of varying voltage and structure. Of the 600 fl appers examined, 123 had malfunctioned within nine months of installation, while the malfunction rate of the 600 spirals studied was zero. Using a Generalized Linear Mixed Model, we found that the rate of fl apper malfunction increased with decreasing fl apper size and power line diameter. Further, the fl apper malfunction rate increased as the distance between poles increased. The cost of replacing malfunctioning BFDs is very high as there are serious health and safety constraints related to working with live wires. Factors aff ecting diverter malfunctioning need to be considered for future powerline projects and our information can serve as basis for developing national standards or regulations for powerline mitigation in Mongolia.

  3. Encefalopatía hepática secundaria a la existencia de un shunt portosistémico tratada satisfactoriamente mediante radiología intervencionista Hepatic encephalophaty secondary to porto-systemic shunt satisfactorily treated with interventionist radiology

    L. Crespo


    Full Text Available La encefalopatía hepática es un estado reversible de alteración en la función cognitiva, que puede ocurrir en pacientes con enfermedad hepática aguda o crónica o shunts porto-sistémicos, en el que puede aparecer cualquiera de los signos neurológicos o psiquiátricos conocidos. Las sustancias nitrogenadas procedentes de la digestión intestinal alcanzan el cerebro sin la depuración que supone su paso por el hígado, debido a las derivaciones porto-sistémicas, y dan lugar a los signos característicos de la encefalopatía hepática. A continuación presentamos dos casos clínicos de pacientes con shunt porto-sistémicos, diagnosticados de encefalopatía hepática crónica recurrente refractaria al tratamiento médico convencional, tratados satisfactoriamente con embolización de dicho shunt mediante técnicas de radiología intervencionista.Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques.

  4. [Cerebrospinal fluid shunts for hydrocephalus and related disorders].

    Ito, Masaki; Houkin, Kiyohiro; Saito, Hisayasu; Shimbo, Daisuke; Motegi, Hiroaki; Kawabori, Masahito; Miyamoto, Michiyuki; Yamauchi, Tomohiro


    Cerebrospinal fluid (CSF) shunts are commonly employed to treat patients with hydrocephalus. A large number of papers have been published focusing on complications and failures of CSF shunts. However, there appears to be a paucity of knowledge comprehensively covering both common complications and rare ones. In this systematic review, we surveyed articles about surgical complications of CSF shunts as comprehensively as possible. Quantitative analysis was performed to determine the frequency of well-known complications, mortality and revision rates of CSF shunts. Furthermore, rare complications of CSF shunts have also been reviewed.

  5. Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders

    Natalie Kaminsky


    Full Text Available The DNA damage response (DDR is a complex biological system activated by different types of DNA damage. Mutations in certain components of the DDR machinery can lead to genomic instability disorders that culminate in tissue degeneration, premature aging, and various types of cancers. Intriguingly, malfunctioning DDR plays a role in the etiology of late onset brain degenerative disorders such as Parkinson’s, Alzheimer’s, and Huntington’s diseases. For many years, brain degenerative disorders were thought to result from aberrant neural death. Here we discuss the evidence that supports our novel hypothesis that brain degenerative diseases involve dysfunction of glial cells (astrocytes, microglia, and oligodendrocytes. Impairment in the functionality of glial cells results in pathological neuro-glial interactions that, in turn, generate a “hostile” environment that impairs the functionality of neuronal cells. These events can lead to systematic neural demise on a scale that appears to be proportional to the severity of the neurological deficit.

  6. Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders

    Natalie Kaminsky; Ofer Bihari; Sivan Kanner; Ari Barzilai


    The DNA damage response (DDR) is a complex biological system activated by different types of DNA damage. Mutations in certain components of the DDR machinery can lead to geno-mic instability disorders that culminate in tissue degeneration, premature aging, and various types of cancers. Intriguingly, malfunctioning DDR plays a role in the etiology of late onset brain degener-ative disorders such as Parkinson’s, Alzheimer’s, and Huntington’s diseases. For many years, brain degenerative disorders were thought to result from aberrant neural death. Here we discuss the evi-dence that supports our novel hypothesis that brain degenerative diseases involve dysfunction of glial cells (astrocytes, microglia, and oligodendrocytes). Impairment in the functionality of glial cells results in pathological neuro-glial interactions that, in turn, generate a‘‘hostile”environment that impairs the functionality of neuronal cells. These events can lead to systematic neural demise on a scale that appears to be proportional to the severity of the neurological deficit.

  7. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J


    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients.

  8. Passively Shunted Piezoelectric Damping of Centrifugally-Loaded Plates

    Duffy, Kirsten P.; Provenza, Andrew J.; Trudell, Jeffrey J.; Min, James B.


    Researchers at NASA Glenn Research Center have been investigating shunted piezoelectric circuits as potential damping treatments for turbomachinery rotor blades. This effort seeks to determine the effects of centrifugal loading on passively-shunted piezoelectric - damped plates. Passive shunt circuit parameters are optimized for the plate's third bending mode. Tests are performed both non-spinning and in the Dynamic Spin Facility to verify the analysis, and to determine the effectiveness of the damping under centrifugal loading. Results show that a resistive shunt circuit will reduce resonant vibration for this configuration. However, a tuned shunt circuit will be required to achieve the desired damping level. The analysis and testing address several issues with passive shunt circuit implementation in a rotating system, including piezoelectric material integrity under centrifugal loading, shunt circuit implementation, and tip mode damping.

  9. Intraparenchymal pericatheter cyst following disconnection of ventriculoperitoneal shunt system

    S Balasubramaniam


    Full Text Available Ventriculoperitoneal (VP shunt is one of the most commonly performed procedures in neurosurgery, but it is also the procedure, which is most prone to complications. Spread of cerebrospinal fluid (CSF into the brain parenchyma is a rare complication of VP shunt and can take the form of CSF edema or a porencephalic cyst. We describe a case of a 1½-year-old child who presented to us with seizures. Computed tomography scan revealed pericatheter porencephalic cyst. Surgical exploration revealed a disconnected VP shunt system. Patient was neurologically observed after shunt extraction. He was seizure free and radiological follow-up showed resolution of cyst. Ours is the first case to document the presence of pericatheter cyst following complete disconnection of shunt system. Though shunt revision is the accepted treatment modality, careful neurological observation can be done after shunt removal especially in asymptomatic cases with compensated hydrocephalus.

  10. A fluid level in an acute extradural haematoma

    Iplikcioglu, M. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey)); Bayar, M.A. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey)); Koekes, F. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey)); Yildiz, B. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey)); Goekcek, C. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey)); Buharali, Z. (Dept. of Neurosurgery, Ministry of Health, Ankara Hospital (Turkey))


    We report a fluid level in an acute extradural haematoma developing after placement of a ventriculoperitoneal shunt for hydrocephalus. This fluid level was thought to be due to a mixture of blood and cerebrospinal fluid. (orig.)

  11. Pathological Predictors of Shunt Stenosis and Hepatic Encephalopathy after Transjugular Intrahepatic Portosystemic Shunt

    Fuliang He


    Full Text Available Background. Transjugular intrahepatic portosystemic shunt (TIPS is an artificial channel from the portal vein to the hepatic vein or vena cava for controlling portal vein hypertension. The major drawbacks of TIPS are shunt stenosis and hepatic encephalopathy (HE; previous studies showed that post-TIPS shunt stenosis and HE might be correlated with the pathological features of the liver tissues. Therefore, we analyzed the pathological predictors for clinical outcome, to determine the risk factors for shunt stenosis and HE after TIPS. Methods. We recruited 361 patients who suffered from portal hypertension symptoms and were treated with TIPS from January 2009 to December 2012. Results. Multivariate logistic regression analysis showed that the risk of shunt stenosis was increased with more severe inflammation in the liver tissue (OR, 2.864; 95% CI: 1.466–5.592; P=0.002, HE comorbidity (OR, 6.266; 95% CI, 3.141–12.501; P<0.001, or higher MELD score (95% CI, 1.298–1.731; P<0.001. Higher risk of HE was associated with shunt stenosis comorbidity (OR, 6.266; 95% CI, 3.141–12.501; P<0.001, higher stage of the liver fibrosis (OR, 2.431; 95% CI, 1.355–4.359; P=0.003, and higher MELD score (95% CI, 1.711–2.406; P<0.001. Conclusion. The pathological features can predict individual susceptibility to shunt stenosis and HE.

  12. The research of the malfunction diagnosis and predictions system in the smart electric grid

    Wang, Yaqing; Zhang, Guoxing; Xu, Hongbing


    The Chinese smart electric grid constriction has been increasing with the technology development. However, the monitoring equipment and background system which should play important roles did not work as intended and restrict to the efficacy of the smart grid. In this essay, it has researched an intelligentized malfunction diagnosis and predictions system which could work with the existed monitoring equipment to function as whole energy monitoring, common malfunction diagnosis, faulted proactive judgment and automatically elimination.

  13. Malfunctions of robotic system in surgery: role and responsibility of surgeon in legal point of view

    Ferrarese Alessia


    Full Text Available Robotic surgery (RS technology has undergone rapid growth in the surgical field since its approval. In clinical practice, failure of robotic procedures mainly results from a surgeon’s inability or to a device malfunction. We reviewed the literature to estimate the impact of this second circumstance in RS and its consequent legal implications. According to data from the literature, device malfunction is rare. We believe it is necessary to complement surgical training with a technical understanding of RS devices.

  14. Who Needs a Revision? 20 Years of Cambridge Shunt Lab.

    Czosnyka, Zofia; Czosnyka, Marek; Pickard, John D; Chari, Aswin


    Shunt testing independent of manufacturers provides knowledge that can significantly improve the management of patients with hydrocephalus. The Cambridge Shunt Evaluation Laboratory was created 20 years ago. Thanks to financial support from the Department of Health (1993-1998), all shunts in use in the UK were systematically evaluated, with "blue reports" being published. Later new devices were tested as they appeared in public domain.Twenty-six models have been evaluated. The majority of the valves had a non-physiologically low hydrodynamic resistance that may result in over-drainage, both related to posture and during nocturnal cerebral vasogenic waves. A long distal catheter increases the resistance of these valves by 100-200 %. Drainage through valves without a siphon-preventing mechanism is very sensitive to body posture. Shunts with siphon-preventing accessories offer a reasonable resistance to negative outlet pressure. Bench parameters were used to test shunt performance in vivo using infusion tests. A criterion for correctly performing a shunt procedure was established. Pressure measured in the shunt prechamber during the plateau phase of infusion should not remain more than 5 mmHg above the le shunt's operating pressure plus hydrodynamic resistance of the valve multiplied by the infusion rate. "Critical levels" for every shunt and every performance level have been used in the shunt testing wizard of ICM+ software.

  15. Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.

    Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha


    The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%).

  16. Nitrogen heat pipe for cryocooler thermal shunt

    Prenger, F.C.; Hill, D.D.; Daney, D.E.; Daugherty, M.A. [Los Alamos National Lab., NM (United States); Green, G.F.; Roth, E.W. [Naval Surface Warfare Center, Annapolis, MD (United States)


    A nitrogen heat pipe was designed, built and tested for the purpose of providing a thermal shunt between the two stages of a Gifford-McMahan (GM) cryocooler during cooldown. The nitrogen heat pipe has an operating temperature range between 63 and 123 K. While the heat pipe is in the temperature range during the system cooldown, it acts as a thermal shunt between the first and second stage of the cryocooler. The heat pipe increases the heat transfer to the first stage of the cryocooler, thereby reducing the cooldown time of the system. When the heat pipe temperature drops below the triple point, the nitrogen working fluid freezes, effectively stopping the heat pipe operation. A small heat leak between cryocooler stages remains because of axial conduction along the heat pipe wall. As long as the heat pipe remains below 63 K, the heat pipe remains inactive. Heat pipe performance limits were measured and the optimum fluid charge was determined.

  17. Dc SQUIDs with asymmetric shunt resistors

    Rudolph, Matthias; Nagel, Joachim; Kemmler, Matthias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut - Experimentalphysik II and Center for Collective Quantum Phenomena in LISAplus, Universitaet Tuebingen (Germany); Meckbach, Johannes Maximilian; Ilin, Konstantin; Siegel, Michael [Institut fuer Mikro- und Nanoelektronische Systeme, Karlsruhe Institute of Technology, Karlsruhe (Germany)


    We have investigated asymmetrically shunted Nb/Al-AlO{sub x}/Nb dc SQUIDs. Simulations based on the coupled Langevin equations predict that the optimum energy resolution ε, and thus also the noise performance of such an asymmetric SQUID, can be 3-4 times better than that of its symmetric counterpart. While keeping the total resistance R identical to a comparable symmetric SQUID with R{sup -1} = R{sub 1}{sup -1} + R{sub 2}{sup -1}, we shunted only one of the two Josephson junctions with R = R{sub 1,2}/2. Both types of SQUIDs were characterized with respect to their transport and noise properties at temperature T = 4.2 K, and we compared the experimental results with numerical simulations. Experiments yielded ε ∼ 32 ℎ for an asymmetric SQUID with an inductance L = 22 pH, whereas a comparable symmetric device achieved ε = 110 ℎ.

  18. Portacaval Shunt for Portal Hypertensive Gastropathy

    John Craig Collins


    Full Text Available Portal hypertensive gastropathy is a vascular disorder of the gastric mucosa distinguished by ectasia of the mucosal capillaries and submucosal veins without inflammation. During 1988 to 1993, 12 patients with biopsyproven cirrhosis (10 alcoholic, 2 posthepatitic were evaluated and treated prospectively by portacaval shunt for active bleeding from severe portal hypertensive gastropathy. Eleven patients had been hospitalized for bleeding three to nine times previously, and one was bleeding uncontrollably for the first time. Requirement for blood transfusions ranged from 11 to 39 units cumulatively, of which 8 to 30 units were required specifically to replace blood lost from portal hypertensive gastropathy. Admission findings were ascites in 9 patients, jaundice in 8, severe muscle wasting in 10, hyperdynamic state in 9. Child's risk class was C in 7, B in 4, A in 1. Ten of the 12 patients had previously received repetitive endoscopic sclerotherapy for esophageal varices, which has been reported to precipitate portal hypertensive gastropathy. Eight patients had failed propranolol therapy for bleeding. Portacaval shunt was performed emergently in 11 patients and electively in 1, and permanently stopped bleeding in all by reducing the mean portal vein-inferior vena cava pressure gradient from 251 to 16 mm saline. There were no operative deaths, and two unrelated late deaths after 13 and 24 months. During 1 to 6.75 years of followup, all shunts remained patent by ultrasonography, the gastric mucosa reverted to normal On serial endoscopy, and there was no gastrointestinal bleeding. Recurrent portal-systemic encephalopathy developed in only 8% of patients. Quality of life was generally good. It is concluded that portacaval shunt provides definitive treatment of bleeding portal hypertensive gastropathy by eliminating the underlying cause, and makes possible prolonged survival with an acceptable quality of life.

  19. The transjugular intrahepatic portosystemic shunt (TIPS)

    Owen, A.R. [Department of Radiology, Austin Health, Heidelberg, Melbourne (Australia)], E-mail:; Stanley, A.J. [Department of Gastroenterology, Glasgow Royal Infirmary, Glasgow (United Kingdom); Vijayananthan, A. [Department of Biomedical Imaging, University of Malaya, Kuala Lumpur (Malaysia); Moss, J.G. [Department of Radiology, Gartnavel General Hospital, Glasgow (United Kingdom)


    The creation of an intrahepatic portosystemic shunt via a transjugular approach (TIPS) is an interventional radiological procedure used to treat the complications of portal hypertension. TIPS insertion is principally indicated to prevent or arrest variceal bleeding when medical or endoscopic treatments fail, and in the management refractory ascites. This review discusses the development and execution of the technique, with focus on its clinical efficacy. Patient selection, imaging surveillance, revision techniques, and complications are also discussed.

  20. Quantitative evaluation fo cerebrospinal fluid shunt flow

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.


    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  1. Mitochondrial function and malfunction in the pathophysiology of pancreatitis.

    Gerasimenko, Oleg V; Gerasimenko, Julia V


    As a primary energy producer, mitochondria play a fundamental role in pancreatic exocrine physiology and pathology. The most frequent aetiology of acute pancreatitis is either gallstones or heavy alcohol consumption. Repeated episodes of acute pancreatitis can result in the development of chronic pancreatitis and increase the lifetime risk of pancreatic cancer 100-fold. Pancreatic cancer is one of the most common causes of cancer mortality with only about 3-4 % of patients surviving beyond 5 years. It has been shown that acute pancreatitis involves Ca²⁺ overload and overproduction of reactive oxygen species in pancreatic acinar cells. Both factors significantly affect mitochondria and lead to cell death. The pathogenesis of inflammation in acute and chronic pancreatitis is tightly linked to the induction of necrosis and apoptosis. There is currently no specific therapy for pancreatitis, but recent findings of an endogenous protective mechanism against Ca²⁺ overload--and particularly the potential to boost this protection--bring hope of new therapeutic approaches.

  2. Major complication after intrauterine vesico-amniotic shunting

    Springer Alexander


    Full Text Available Bilateral foetal uropathy is the leading cause of chronic renal failure in childhood. Vesico-amniotic shunting (VAS is a simple, feasible, and widely used procedure for decompressing the foetal urinary system. We report a case of a boy with bilateral foetal uropathy who underwent VAS at a gestational age of 29 weeks. Vesico-abdominal shunt dislodgement occurred and led to urinary ascites and anhydramnios. Postpartal laparotomy showed a shunt perforation between the urinary bladder and the peritoneal cavity.

  3. Ventriculoperitoneal shunt for intracranial hypertension in cryptococcal meningitis without hydrocephalus.

    Petrou, Panayota; Moscovici, Samuel; Leker, Ronen R; Itshayek, Eyal; Gomori, John M; Cohen, José E


    The use of a ventriculoperitoneal (VP) shunt to treat uncontrollable intracranial hypertension in patients with cryptococcal meningitis without hydrocephalus is somewhat unusual and still largely unreported. However, uncontrollable intracranial hypertension without hydrocephalus in these patients is a potentially life-threatening condition. Early diagnosis and shunt placement are essential to improve survival and neurological function. We report uncontrollable intracranial hypertension without hydrocephalus in a 23-year-old woman, which was successfully managed by VP shunt placement.

  4. Morbidity and mortality after peritoneovenous shunt surgery for refractory ascites.

    Rubinstein, D; McInnes, I; Dudley, F


    A prospective analysis of the morbidity and mortality after peritoneovenous shunting was carried out in 25 patients who had a total of 27 shunts for refractory ascites. Major complications were limited to the patients in whom ascites was secondary to hepatic rather than peritoneal disease. Immediate postoperative complications followed 17 out of the 23 shunts carried out in patients with liver disease and included septicaemia (two), profound hypotension (two), pulmonary oedema (one), and clin...

  5. A compact, coaxial shunt current diagnostic for X pinches.

    Wang, Liangping; Zhang, Jinhai; Li, Mo; Zhang, Xinjun; Zhao, Chen; Zhang, Shaoguo


    A compact coaxial shunt was applied in X-pinches experiments on Qiangguang pulsed power generator. The coaxial shunt was designed to have a compact construction for smaller inductance and more, for conveniently assembling upon the X pinch load structure. The coaxial shunt is also a cheap current probe and was easily built by research groups. The shunt can monitor a 100 kA high current with a 100 ns rise time. The calibration results showed that the probe used in the experiments has a resistance of 3.2 mΩ with an uncertainty of 3%, and its response time to the step signal is less than 7 ns.

  6. Superconducting fault current-limiter with variable shunt impedance

    Llambes, Juan Carlos H; Xiong, Xuming


    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  7. Rate of shunt revision as a function of age in patients with shunted hydrocephalus due to myelomeningocele.

    Dupepe, Esther B; Hopson, Betsy; Johnston, James M; Rozzelle, Curtis J; Jerry Oakes, W; Blount, Jeffrey P; Rocque, Brandon G


    OBJECTIVE It is generally accepted that cerebrospinal fluid shunts fail most frequently in the first years of life. The purpose of this study was to describe the risk of shunt failure for a given patient age in a well-defined cohort with shunted hydrocephalus due to myelomeningocele (MMC). METHODS The authors analyzed data from their institutional spina bifida research database including all patients with MMC and shunted hydrocephalus. For the entire population, the number of shunt revisions in each year of life was determined. Then the number of patients at risk for shunt revision during each year of life was calculated, thus enabling them to calculate the rate of shunt revision per patient in each year of life. In this way, the timing of all shunt revision operations for the entire clinic population and the likelihood of having a shunt revision during each year of life were calculated. RESULTS A total of 655 patients were enrolled in the spina bifida research database, 519 of whom had a diagnosis of MMC and whose mean age was 17.48 ± 11.7 years (median 16 years, range 0-63 years). Four hundred seventeen patients had had a CSF shunt for the treatment of hydrocephalus and thus are included in this analysis. There were 94 shunt revisions in the 1st year of life, which represents a rate of 0.23 revisions per patient in that year. The rate of shunt revision per patient-year initially decreased as age increased, except for an increase in revision frequency in the early teen years. Shunt revisions continued to occur as late as 43 years of age. CONCLUSIONS These data substantiate the idea that shunt revision surgeries in patients with MMC are most common in the 1st year of life and decrease thereafter, except for an increase in the early teen years. A persistent risk of shunt failure was observed well into adult life. These findings underscore the importance of routine follow-up of all MMC patients with shunted hydrocephalus and will aid in counseling patients and

  8. Memory and selective learning in children with spina bifida-myelomeningocele and shunted hydrocephalus: A preliminary study

    Vachha Behroze


    Full Text Available Abstract Background Selective learning is the ability to select items of relevance from among less important items. Limited evidence exists regarding the efficiency with which children with spina bifida-myelomeningocele and shunted hydrocephalus (SB/SH are able to learn information. This report describes initial data related to components of learning and metacognitive skills in children with SB/SH. Methods Twenty six children with SB/SH and 26 controls (age: 7 – 16 y with average intelligence, and monolingual English-speaking backgrounds participated in the study. Exclusion criteria for the SB/SH group were: prior history of shunt infection, history of seizure or shunt malfunction within the previous three months, prior diagnoses of attention disorders and/or clinical depression. Children were presented lists of words with equal exemplars each of two distinct semantic categories (e.g. fruits, animals, and told to make as high a score as possible by learning the words. The value of the words was designated by category membership (e.g. animals = low value; fruits = high value. The total number of words learned across three learning trials was used to determine memory span. Selective learning efficiency (SLE was computed as the efficiency with which items of greater value were selectively learned across three trials. Results Children with SB/SH did worse than controls on memory span (P Conclusion Success in school is often dependent on the ability to recall important facts selectively and ignore less important information. Children with SB/SH in our study had a poor memory span and were unable to monitor and report an efficient and workable metacognitive strategy required to remember a list of words. Preliminary findings may begin to explain our previous clinical and research findings wherein children with SB/SH often focus on extraneous details, but demonstrate difficulty remembering the main gist of a story/event.

  9. Is Subdural Peritoneal Shunt Placement an Effective Tool for the Management of Recurrent/Chronic Subdural Hematoma?

    Alvarez-Pinzon, Andres M; Valerio, Jose E; Delgado, Victor; Escalante, Jennifer A; Lopez, Nithia; Wolf, Aizik L


    Objective  To describe a surgical technique and to report using a retrospective study the efficacy of peritoneal shunts for the treatment of recurrent/chronic subdural hematoma (CSDH). We describe the considerations, complications, and outcomes related to this technique. Methods  In a retrospective cohort study, 125 charts with a diagnosis of subacute/chronic subdural hematoma were assigned for evaluation. Of the charts reviewed, 18 charts were found from subjects with a diagnosis of recurrent sub-acute or chronic subdural hematoma. All patients had undergone initial surgical treatment of their condition followed by peritoneal shunt placement to help alleviate intracranial pressure. Factors including the age, size of subdural hematoma, number of previous events, BMI, complications, survival, and clinical course were analyzed. Results  After subdural peritoneal shunt placement all patients had full neurological recovery with no complaints of headaches, lethargy, weakness, confusion or seizures. None of the cases had new subdural hematoma episodes after placement for a minimum of a two-year period (mean 26.1 months) (range 24.3-48.6 months). No postoperative complications were reported. The rates of postoperative hemorrhage, infection, distal catheter revision, and perioperative seizures was found to be zero percent. Shunt drainage was successful in all cases, draining 85% of the blood in the first 48 hours. There was no significant relationship between complications and the use of anticoagulants four weeks after surgery. Conclusions Peritoneal shunts, though rarely used, are a viable option in the treatment of sub-acute/chronic subdural hematomas. When pursuing this treatment, this technique is recommended to mitigate the risks of repeat surgical intervention and lessen perioperative time in high-risk patients. PMID:27335718

  10. 急性高容量血液稀释对单肺通气病人氧合及肺内分流的影响%Effects of acute hypervolemic hemodilution on oxygenation and pulmonary shunt fraction during one lung ventilation in patients

    司建洛; 邢群智; 陈靖军; 伍军


    目的 探讨轻度急性高容量血液稀释(AHHD)对单肺通气(OLV)病人氧合和肺内分流的影响.方法 将40例ASAⅠ~Ⅱ级全麻下行食道癌手术患者,随机分为两组,H组(血液稀释组)和C组(对照组),每组20例,麻醉诱导后插入双腔支气管插管,桡动脉穿刺测量有创血压和采集动脉血标本,中心静脉置入双腔静脉导管,深度17~18cm,血液稀释组经静脉快速输入羟乙基淀粉130/0.4(万汶)15 ml/kg,30 ml/min行急性高容量血液稀释,术中保持红细胞压积(Hct)在30%以上,对照组按常规开胸手术输液管理.分别在双肺通气后20min(T1)、单肺通气后20 min(T2),40,in(T3)、80Min(T4)、再次双肺通气30 min(T5)采动脉血和混合静脉血进行血气分析,按标准公式计算分流率,测动脉血乳酸(Lac)浓度.结果 与双肺通气相比,两组在单肺通气(OLV)期间动脉血氧分压(PaO2)和静脉血氧分压(PrO2)明显降低(P<0.05),两组在OLV期间单肺通气后分流值(Qs/Qt)和气道压力(Paw)明显增加(P<0.05).pH、Lac变化差异无统计学意义(P>0.05).与对照组相比,各时点pH、PaO2、Qs/Qt、Paw、Lac差异无统计学意义(P>0.05).血液稀释组在OLV期间PvO2明显降低(P<0.05),血液稀释组在OLV期间PaCO2明显升高(P<0.05).结论 轻度AHHD不明显增加OLV期间肺内分流率,但对血气有影响,加强OLV期间的通气管理,轻度AHHD可以安全应用于胸科手术.%Objective To investigate the effects of mild acute hypervolemic hemedilution (AHHD) on oxygenation and pul-monary shunt fraction during one lung ventilation (OLV) in patients. Methods Forty ASA Ⅰ-Ⅱ patients who underwent esoph-ageal cancer resection were randomly divided into two groups, group H(twenty patients with AHHD) and group C(twenty patients without AHHD), all patients were induced with 2-4 μg/kg fentanyl, 0.1 mg/kg midazolam,, 0.15 mg/kg vecuronium and 1 mg/kg propofol. Double lumen endobrouchial tube was inserted after

  11. Novel current monitoring techniques without shunt resistors

    VODA Adriana


    Full Text Available Current measurement for automotiveelectrical actuator applications (with motors or valvesis necessary for appropriate control in many cases anda safety requirement in all cases: the control algorithmmay be dependent on the data but safety relevantfunctions will use it to determine possible over-current,over-temperature or failure conditions. This paperproposes an alternative method of monitoring thecurrent, without using sensors or current shunts.Instead, measurements are made on the motor in thedevelopment stages and low/high frequency variationsin the supply line are monitored, through low/highpassfilters, by available AD channels in the system.This results in cost reduction for the final product, byreducing hardware complexity.

  12. Leakage Inductance Calculation for Planar Transformers with a Magnetic Shunt

    Jun, Zhang; Ouyang, Ziwei; Duffy, M. C.


    with a magnetic shunt by means of the stored magnetic energy in the primary and secondary sides of the transformer using the magnetomotive force (MMF) variation method, as well as the stored energy in the shunt based on the reluctance model. The detailed calculation method is described. Both the FEA simulation...

  13. Leakage Inductance Calculation for Planar Transformers with a Magnetic Shunt

    Zhang, Jun; Ouyang, Ziwei; Duffy, Maeve C.


    with a magnetic shunt by means of the stored magnetic energy in the primary and secondary sides of the transformer using the magnetomotive force (MMF) variation method, as well as the stored energy in the shunt based on the reluctance model. The detailed calculation method is described. Both the FEA simulation...

  14. Shunted-Josephson-junction model. II. The nonautonomous case

    Belykh, V. N.; Pedersen, Niels Falsig; Sørensen, O. H.


    The shunted-Josephson-junction model with a monochromatic ac current drive is discussed employing the qualitative methods of the theory of nonlinear oscillations. As in the preceding paper dealing with the autonomous junction, the model includes a phase-dependent conductance and a shunt capacitance...

  15. Transcaval transjugular intrahepatic portosystemic shunt: preliminary clinical results

    Lee, Kwang Hun; Lee, Do Yun; Won, Jong Yoon [Yonsei University College of Medicine, Seoul (Korea, Republic of); Park, Sang Joon [Hallym University College of Medicine, Seoul (Korea, Republic of); Kim, Jae Kyu; Yoon, Woong [Chonnam National University Hospital, Gwangju (Korea, Republic of)


    To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with unusual anatomy between the hepatic veins and portal bifurcation, and inaccessible or inadequate hepatic veins. Transcaval TIPS, performed in six patients, was indicated by active variceal bleeding (n=2), recurrent variceal bleeding (n=2), intractable ascites (n=1), and as a bridge to liver transplantation (n=1). The main reasons for transcaval rather than classic TIPS were the presence of an unusually acute angle between the hepatic veins and the level of the portal bifurcation (n=3), hepatic venous occlusion (n=2), and inadequate small hepatic veins (n=1). Technical and functional success was achieved in all patients. The entry site into liver parenchyma from the inferior vena cava was within 2 cm of the atriocaval junction. Procedure-related complications included the death of one patient due to hemoperitoneum despite the absence of contrast media spillage at tractography, and another suffered reversible hepatic encephalopathy. In patients with unusual anatomy between the hepatic veins and portal bifurcation, and inaccessible or inadequate hepatic veins, transcaval TIPS creation is feasible.

  16. Syringomyelia regression after shunting of a trapped fourth ventricle

    Dukagjin Morina


    Full Text Available We describe a case of progressive syringomyelia following post-infectious trapped fourth ventricle (TFV, which resolved after shunting of the fourth ventricle. A 28-year-old female who had previously undergone treatment of intracerebral hemorrhage and meningitis developed a hydrocephalus with TFV. After 3 years she developed disturbance of walking and coordination. Cranial-CT revealed an enlargement of the shunted fourth ventricle as a result of shunt dysfunction. Furthermore a cervical syringomyelia developed. The patient underwent a revision of a failed fourth ventriculo- peritoneal shunt. Postoperatively, syringomyelia resolved within 6 months and the associated neurological deficits improved significantly. An insufficiency of cerebrospinal fluid draining among patients with TFV can be associated with communicating syringomyelia. An early detection and treatment seems important on resolving syringomyelia and avoiding permanent neurological deficits. Ventriculo-peritoneal shunt in trapped fourth ventricles can resolve a secondary syringomyelia.

  17. Percutaneous peritoneovenous shunt positioning: technique and preliminary results

    Orsi, Franco; Grasso, Rosario Francesco; Bonomo, Guido; Marinucci, Irene [Division of Radiology, European Institute of Oncology, Milan (Italy); Monti, Cinzia [Institute of Radiology, University of Milan (Italy); Bellomi, Massimo [Division of Radiology, European Institute of Oncology, Milan (Italy); Institute of Radiology, University of Milan (Italy)


    Nine peritoneovenous shunts were positioned by percutaneous technique in seven patients with advanced malignancy causing severe refractory ascites, and in two patients with hepatic cirrhosis (one with hepatocarcinoma). In all patients the shunts were percutaneously placed through the subclavian vein in the angiographic suite under digital fluoroscopic guide. No complications directly related to the procedure occurred. The shunt was successfully positioned in all patients in 60 min average time. No patient showed symptoms related to pulmonary overload or to disseminated intravascular coagulation. All patients had a significant improvement of the objective symptoms related to ascites such as respiratory symptoms, dyspepsia, and functional impairment to evacuation describing an improvement of their quality of life. Maximum shunt patency was 273 days. Percutaneous placement of peritoneovenous shunt is a safe, fast, and inexpensive procedure, extremely useful in resolution of refractory ascites, reducing symptoms, and allowing effective palliation, with a great improvement in quality of life. (orig.)

  18. Portasystemic shunt fraction quantification with colonic iodine-123 iodoamphetamine

    Yen, C.K.; Pollycove, M.; Crass, R.; Lin, T.H.; Baldwin, R.; Lamb, J.


    Portasystemic shunting was quantified in dogs with (/sup 123/I)iodoamphetamine (IMP) administered transrectally into the colon and monitored externally with a gamma camera. IMP was absorbed rapidly and unchanged from the colon. After direct injection into the portal vein, IMP was almost completely extracted by the liver on the first pass, and the washout half-life was approximately 60 min. Based on these kinetic data, computer simulation of this biologic system was carried out. Errors associated with simplified models are calculated. The simplest model with insignificant error, which assumed that the tracer behaved like microspheres, was used to quantitate portasystemic shunt fraction in animals with surgically created shunts. Results were compared with the standard of /sup 99m/Tc-labeled macroaggregated albumin infused into a branch of inferior mesenteric vein. For shunt fractions ranging from 0 to 100%, an excellent correlation was seen, indicating that this approach is potentially a simple, noninvasive method of portasystemic shunt fraction quantification.

  19. The role of lumboperitoneal shunts in the treatment of syringomyelia.

    Oluigbo, Chima O; Thacker, Karen; Flint, Graham


    OBJECT The role of thecoperitoneal shunts in the management of syringomyelia is not well defined. In this study, the authors analyze the outcome of lumboperitoneal shunt procedures carried out to treat syringomyelia in their institution. METHODS The authors retrospectively reviewed the medical records of 19 patients who underwent lumboperitoneal shunt procedures for syringomyelia. RESULTS The mean follow-up duration was 25 months (range 3-51 months). Of 16 cases followed up, only 5 patients reported clinical improvement in their preoperative symptoms, but of these, 2 had clear radiological evidence of improvement. Three of 6 patients with syringomyelia due to spinal arachnoiditis improved. CONCLUSIONS Lumboperitoneal shunts may lead to useful improvement in the symptoms of a patient with syringomyelia while avoiding the risk of neurological deterioration inherent in myelotomies required for syrinx shunting procedures.

  20. Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age

    Heider Peter


    Full Text Available Abstract Introduction A number of studies has addressed the possible association between patent foramen ovale (PFO and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke. Methods To address the role of PFO for the occurrence of cerebral ischemia, we investigated the prevalence of right-to-left shunt in a large group of patients with acute stroke or TIA. 763 consecutive patients admitted to our hospital with cerebral ischemia were analyzed. All patients were screened for the presence of PFO by contrast-enhanced transcranial Doppler sonography at rest and during Valsalva maneuver. Subgroup analyses were performed in patients stratified for gender, age and origin of stroke. Results A right-to-left shunt was detected in 140 (28% male and in 114 (42% female patients during Valsalva maneuver, and in 66 (13% and 44 (16% at rest respectively. Patients with right-to-left shunt were younger than those without (P P = 0.001 but not female patients (P > 0.05. After adjusting for age no significant association between PFO and stroke of unknown origin was found in either group. Conclusion Our findings argue against paradoxical embolization as a major cause of cerebral ischemia in patients with right-to-left shunt. Our data demonstrate substantial gender-and age-related differences that should be taken into account in future studies.

  1. Flexural waves focusing through shunted piezoelectric patches

    Yi, K.; Collet, M.; Ichchou, M.; Li, L.


    In this paper, we designed and analyzed a piezo-lens to focus flexural waves in thin plates. The piezo-lens is comprised of a host plate and piezoelectric arrays bonded on the surfaces of the plate. The piezoelectric patches are shunted with negative capacitance circuits. The effective refractive indexes inside the piezo-lens are designed to fit a hyperbolic secant distribution by tuning the negative capacitance values. A homogenized model of a piezo-mechanical system is adopted in the designing process of the piezo-lens. The wave focusing effect is studied by the finite element method. Numerical results show that the piezo-lens can focus flexural waves by bending their trajectories, and is effective in a large frequency band. The piezo-lens has the ability to focus flexural waves at different locations by tuning the shunting negative capacitance values. The piezo-lens is shown to be effective for flexural waves generated by different types of sources.

  2. Ventriculoperitoneal shunt infection with Listeria innocua.

    Karli, Arzu; Sensoy, Gulnar; Unal, Nevzat; Yanik, Keramettin; Cigdem, Halit; Belet, Nursen; Sofuoglu, Ayse


    Listeria species may cause life-threatening events including meningitis and invasive infection in newborns, pregnant women, older and immunodeficient people. The most common Listeria species that causes infection is L. monocytogenes. It is known that Listeria innocua has no pathogenicity. A 9-month-old baby had ventriculoperitoneal shunt and was treated with adrenocorticotropic hormone because of infantile spasms. He was brought to hospital with fever and vomiting. Upon physical examination, the patient seemed uncomfortable and had a temperature of 38.6°C. Laboratory results were as follows: hemoglobin, 6.7 g/dL; leukocyte count, 5420/mm(3) ; platelet count, 169,000/mm(3) ; and C-reactive protein, 100 mg/L (normal <5 mg/L). On analysis of cerebrospinal fluid (CSF), leukocyte count was 480/mm(3) , protein was 46 mg/dL and CSF glucose was 35 mg/dL. L. innocua was isolated in CSF culture. We describe this unusual case of ventriculoperitoneal shunt infection with L. innocua.

  3. Evaluation of the use of automatic exposure control and automatic tube potential selection in low-dose cerebrospinal fluid shunt head CT

    Wallace, Adam N.; Bagade, Swapnil; Chatterjee, Arindam; Hicks, Brandon; McKinstry, Robert C. [Barnes Jewish Hospital, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, St. Louis, MO (United States); Vyhmeister, Ross [Washington University School of Medicine, St. Louis, MO (United States); Ramirez-Giraldo, Juan Carlos [Siemens Healthcare, Malvern, PA (United States)


    Cerebrospinal fluid shunts are primarily used for the treatment of hydrocephalus. Shunt complications may necessitate multiple non-contrast head CT scans resulting in potentially high levels of radiation dose starting at an early age. A new head CT protocol using automatic exposure control and automated tube potential selection has been implemented at our institution to reduce radiation exposure. The purpose of this study was to evaluate the reduction in radiation dose achieved by this protocol compared with a protocol with fixed parameters. A retrospective sample of 60 non-contrast head CT scans assessing for cerebrospinal fluid shunt malfunction was identified, 30 of which were performed with each protocol. The radiation doses of the two protocols were compared using the volume CT dose index and dose length product. The diagnostic acceptability and quality of each scan were evaluated by three independent readers. The new protocol lowered the average volume CT dose index from 15.2 to 9.2 mGy representing a 39 % reduction (P < 0.01; 95 % CI 35-44 %) and lowered the dose length product from 259.5 to 151.2 mGy/cm representing a 42 % reduction (P < 0.01; 95 % CI 34-50 %). The new protocol produced diagnostically acceptable scans with comparable image quality to the fixed parameter protocol. A pediatric shunt non-contrast head CT protocol using automatic exposure control and automated tube potential selection reduced patient radiation dose compared with a fixed parameter protocol while producing diagnostic images of comparable quality. (orig.)

  4. Evaluation of Shunt Losses in Industrial Silicon Solar Cells

    P. Somasundaran


    Full Text Available Shunting is one of the key issues in industrial silicon solar cells which degrade cell performance. This paper presents an approach for investigation of the performance degradation caused by the presence of ohmic extended shunts at various locations in industrial silicon solar cells. Location, nature, and area of the shunts existing in solar cells have been examined by lock-in infrared thermography (LIT. Based on LIT images and experimental dark I-V curves of solar cell, shunted cell has been modeled, from which loss in fill factor and efficiency due to the specific shunt has been obtained. Distributed diode modeling approach of solar cell has been exploited for obtaining simulation results which were supported by experimental measurements. The presented approach is useful to estimate performance reduction due to specific shunts and to quantify losses, which can help in improving the efficiency of solar cell during production by tackling the shunt related problems based on the level of severity and tolerance.

  5. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

    Sotelo, Julio


    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus.

  6. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections.

    Cökeliler, D; Caner, H; Zemek, J; Choukourov, A; Biederman, H; Mutlu, M


    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.

  7. A plasma polymerization technique to overcome cerebrospinal fluid shunt infections

    Coekeliler, D [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey); Caner, H [Department of Neurosurgery, School of Medicine, Baskent University, 06610, Ankara (Turkey); Zemek, J [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53, Prague, Czech Republic (Czech Republic); Choukourov, A [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Biederman, H [Department of Macromolecular Physics, Charles University, V Holesovickach 2, 18000 Prague (Czech Republic); Mutlu, M [Plasma Aided Bioengineering and Biotechnology Research Laboratory, Engineering Faculty, Hacettepe University, 06532, Ankara (Turkey)


    Prosthetic devices, mainly shunts, are frequently used for temporary or permanent drainage of cerebrospinal fluid. The pathogenesis of shunt infection is a very important problem in modern medicine and generally this is characterized by staphylococcal adhesion to the cerebrospinal fluid shunt surfaces. In this paper, the prevention of the attachment of test microorganism Staphylococcus epidermidis on the cerebrospinal fluid shunt surfaces by 2-hydroxyethylmethacrylate (HEMA) precursor modification in the plasma polymerization system, is reported. Different plasma polymerization conditions (RF discharge power 10-20-30 W, exposure time 5-10-15 min) were employed during the surface modification. The surface chemistry and topology of unmodified and modified shunts was characterized by x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, static contact angle measurements were performed to state the change of surface hydrophilicity. All samples were tested in vitro with Staphylococcus epidermidis. A plasma-polymerized HEMA film (PP HEMA) was found to be an alternative simple method to decrease the microorganism attachment and create bacterial anti-fouling surfaces. The attachment of the model microorganism Staphylococcus epidermidis on the shunt surface modified by PP HEMA at 20 W and 15 min was reduced 62.3% if compared to the unmodified control surface of the shunt.

  8. Correction of malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance

    Lee, Seung Ryong; Baek, Kyong Hee; Jung, Gyoo Sik; Huh, Jin Do; Joh, Young Duk; Rim, Hark [Kosin Medical College, Pusan (Korea, Republic of)


    To determine the efficacy of correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance. Between November 1994 and March 1997, we performed 15 manipulations in 12 patients in whom a dual-cuff, straight Tenckhoff peritoneal dialysis catheter had been implanted due to chronic renal failure. The causes of catheter malfunctioning were inadequate drainage of the dialysate(n=14) and painful dialysis(n=1). Under fluoroscopic guidance, adhesiolysis and repositioning of the malfunctioning catheter were performed with an Amplatz Super Stiff guidewire and the stiffener from a biliary drainage catheter. The results of procedures were categorized as either immediate or durable success, this latter being defined as adequate catheter function for at least one month after the procedure. Immediate success was achieved in 14 of 15 procedures (93%), and durable success in 7 of 15(47%). The mean duration of catheter function was 157 (range, 30 to 578) days. After manipulation, abdominal pain developed in eight patients and peritonitis in two, but with conservative treatment, these symptoms improved. The correction of a malfunctioning peritoneal dialysis catheter with guidewire and stiffener under fluoroscopic guidance is an effective means of restoring catheter function and may be an effective alternative to surgical reimplantation of the catheter, or hemodialysis.

  9. Loss of labor time due to malfunctioning ICTs and ICT skill insufficiencies

    Deursen, van Alexander; Dijk, van Jan


    Purpose – The purpose of this paper is to unexplore the area of information and communication technology (ICT) use in organizations related to the assumed productivity gains by the use of ICTs. On the one hand, the paper focus on the losses of labor time that are caused by malfunctioning hardware o

  10. Ion beam sputter-etched ventricular catheter for hydrocephalus shunt

    Banks, B. A. (Inventor)


    A cerebrospinal fluid shunt in the form of a ventricular catheter for controlling the condition of hydrocephalus by relieving the excessive cerebrospinal fluid pressure is described. A method for fabrication of the catheter and shunting the cerebral fluid from the cerebral ventricles to other areas of the body is also considered. Shunt flow failure occurs if the ventricle collapse due to improper valve function causing overdrainage. The ventricular catheter comprises a multiplicity of inlet microtubules. Each microtubule has both a large openings at its inlet end and a multiplicity of microscopic openings along its lateral surfaces.

  11. Power System Harmonic Compensation Using Shunt Active Power Filter.

    Shiuly Mukherjee


    Full Text Available This paper shows the method of improving the power quality using shunt active power filter. The proposedtopic comprises of PI controller, filter hysteresis current control loop, dc link capacitor. The switching signal generation for filter is fromhysteresis current controller techniques. With the all these element shunt active power filter reduce the total harmonic distortion. Thispaper represents the simulation and analysis of the using three phase three wire system active filter to compensate harmonics .Theproposed shunt active filter model uses balanced non-linear load. This paper successfully lowers the THD within IEEE norms and satisfactorily works to compensatecurrent harmonics.

  12. Pollutants removal in subsurface infiltration systems by shunt distributing wastewater with/without intermittent aeration under different shunt ratios.

    Pan, Jing; Yuan, Fang; Zhang, Yang; Huang, Linli; Yu, Long; Zheng, Fanping; Cheng, Fan; Zhang, Jiadi


    Matrix dissolved oxygen (DO), removal of COD, TP and nitrogen in subsurface infiltration systems (SISs), named SIS A (without intermittent aeration and shunt distributing wastewater), SIS B (with shunt distributing wastewater) and SIS C (with intermittent aeration and shunt distributing wastewater) were investigated. Aerobic conditions were developed in 50cm depth and anoxic or anaerobic conditions were not changed in 80 and 110cm depth by intermittent aeration. Under appropriate shunt ratios, shunt distributing wastewater improved denitrification and had little influence on COD, TP and NH3-N removal. Under the optimal shunt ratio of 1:2 for SIS C, high average removal rates of COD (90.06%), TP (93.17%), NH3-N (88.20%) and TN (85.79%) were obtained, which were higher than those in SIS A (COD: 82.56%, TP: 92.76%, NH3-N: 71.08%, TN: 49.24%) and SIS B (COD: 81.12%, TP: 92.58%, NH3-N: 69.14%, TN: 58.73%) under the optimal shunt ratio of 1:3.

  13. Clopidogrel in infants with systemic-to-pulmonary-artery shunts

    Wessel, David L; Berger, Felix; Li, Jennifer S


    BACKGROUND: Infants with cyanotic congenital heart disease palliated with placement of a systemic-to-pulmonary-artery shunt are at risk for shunt thrombosis and death. We investigated whether the addition of clopidogrel to conventional therapy reduces mortality from any cause and morbidity related...... to the shunt. METHODS: In a multicenter, double-blind, event-driven trial, we randomly assigned infants 92 days of age or younger with cyanotic congenital heart disease and a systemic-to-pulmonary-artery shunt to receive clopidogrel at a dose of 0.2 mg per kilogram of body weight per day (467 infants...... days of age. RESULTS: The rate of the composite primary end point did not differ significantly between the clopidogrel group (19.1%) and the placebo group (20.5%) (absolute risk difference, 1.4 percentage points; relative risk reduction with clopidogrel, 11.1%; 95% confidence interval, -19.2 to 33.6; P...

  14. Effects of an interatrial shunt on rest and exercise hemodynamics

    Kaye, David; Shah, Sanjiv J; Borlaug, Barry A


    BACKGROUND: A treatment based on an interatrial shunt device has been proposed for counteracting elevated pulmonary capillary wedge pressure (PCWP) in patients with heart failure and mildly reduced or preserved ejection fraction (HFpEF). We tested the theoretical hemodynamic effects...... of the conditions tested. CONCLUSIONS: The interatrial shunt reduced left-sided cardiac output with a marked reduction in PCWP. This approach may reduce the propensity for heart failure exacerbations and allow patients to exercise longer, thus attaining higher heart rates and cardiac outputs with the shunt compared...... of this approach with the use of a previously validated cardiovascular simulation. METHODS AND RESULTS: Rest and exercise hemodynamics data from 2 previous independent studies of patients with HFpEF were simulated. The theoretical effects of a shunt between the right and left atria (diameter up to 12 mm) were...

  15. Digital implementation of shunting-inhibitory cellular neural network

    Hammadou, Tarik; Bouzerdoum, Abdesselam; Bermak, Amine


    Shunting inhibition is a model of early visual processing which can provide contrast and edge enhancement, and dynamic range compression. An architecture of digital Shunting Inhibitory Cellular Neural Network for real time image processing is presented. The proposed architecture is intended to be used in a complete vision system for edge detection and image enhancement. The present hardware architecture, is modeled and simulated in VHDL. Simulation results show the functional validity of the proposed architecture.

  16. Hemodynamics of patient-specific aorta-pulmonary shunt configurations

    Pekkan, Kerem; Pişkin, Senol; Altın, H. Fırat; Yıldız, Okan; Bakır, İhsan


    Optimal hemodynamics in aorta-pulmonary shunt reconstruction is essential for improved post-operative recovery of the newborn congenital heart disease patient. However, prior to in vivo execution, the prediction of post-operative hemodynamics is extremely challenging due to the interplay of multiple confounding physiological factors. It is hypothesized that the post-operative performance of the surgical shunt can be predicted through computational blood flow simulations that consider patient ...

  17. In vitro flow measurements in ion sputtered hydrocephalus shunts

    Cho, Y. I.; Back, L. H.


    This paper describes an experimental procedure for accurate measurements of the pressure-drop/flow rate relationship in hydrocephalus shunts. Using a fish-hook arrangement, small flow rates in a perforated ion-sputtered Teflon microtubule were measured in vitro in a pressured system and were correlated with pressure in the system. Results indicate that appropriate drainage rates could be obtained in the physiological range for hydrocephalus shunts.

  18. Cross-species functionality of pararetroviral elements driving ribosome shunting.

    Mikhail M Pooggin

    Full Text Available BACKGROUND: Cauliflower mosaic virus (CaMV and Rice tungro bacilliform virus (RTBV belong to distinct genera of pararetroviruses infecting dicot and monocot plants, respectively. In both viruses, polycistronic translation of pregenomic (pg RNA is initiated by shunting ribosomes that bypass a large region of the pgRNA leader with several short (sORFs and a stable stem-loop structure. The shunt requires translation of a 5'-proximal sORF terminating near the stem. In CaMV, mutations knocking out this sORF nearly abolish shunting and virus viability. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that two distant regions of the CaMV leader that form a minimal shunt configuration comprising the sORF, a bottom part of the stem, and a shunt landing sequence can be replaced by heterologous sequences that form a structurally similar configuration in RTBV without any dramatic effect on shunt-mediated translation and CaMV infectivity. The CaMV-RTBV chimeric leader sequence was largely stable over five viral passages in turnip plants: a few alterations that did eventually occur in the virus progenies are indicative of fine tuning of the chimeric sequence during adaptation to a new host. CONCLUSIONS/SIGNIFICANCE: Our findings demonstrate cross-species functionality of pararetroviral cis-elements driving ribosome shunting and evolutionary conservation of the shunt mechanism. We are grateful to Matthias Müller and Sandra Pauli for technical assistance. This work was initiated at Friedrich Miescher Institute (Basel, Switzerland. We thank Prof. Thomas Boller for hosting the group at the Institute of Botany.

  19. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N


    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status.

  20. Ventriculoperitoneal shunt infection with Mycobacterium fortuitum: a rare offending organism.

    Cadena, Gilbert; Wiedeman, Jean; Boggan, James E


    Postsurgical infection is one of the greatest potential morbidities of ventriculoperitoneal shunt surgery. The majority of infections can be linked to contamination with skin flora at the time of surgery, a phenomenon that has been well described. However, there is a paucity of literature regarding infection with nontuberculous mycobacteria. The authors report a case of postoperative ventriculoperitoneal shunt infection with Mycobacterium fortuitum and review the available neurosurgical literature and treatment strategies.

  1. Calibration of piezoelectric RL shunts with explicit residual mode correction

    Høgsberg, Jan; Krenk, Steen


    Piezoelectric RL (resistive-inductive) shunts are passive resonant devices used for damping of dominant vibration modes of a flexible structure and their efficiency relies on the precise calibration of the shunt components. In the present paper improved calibration accuracy is attained by an extension of the local piezoelectric transducer displacement by two additional terms, representing the flexibility and inertia contributions from the residual vibration modes not directly addressed by the shunt damping. This results in an augmented dynamic model for the targeted resonant vibration mode, in which the residual contributions, represented by two correction factors, modify both the apparent transducer capacitance and the shunt circuit impedance. Explicit expressions for the correction of the shunt circuit inductance and resistance are presented in a form that is generally applicable to calibration formulae derived on the basis of an assumed single-mode structure, where modal interaction has been neglected. A design procedure is devised and subsequently verified by a numerical example, which demonstrates that effective mitigation can be obtained for an arbitrary vibration mode when the residual mode correction is included in the calibration of the RL shunt.

  2. Triggerless vacuum shunting plasma by metallic and solid materials

    Yukimura, Ken; Tani, Yuuji; Masamune, Sadao


    Shunting discharge is an alternating capacitor discharge through a rod of solid-state or metallic materials. Optimization of the discharge condition has realized self-ignition of the arc discharge with low input power to the rod, leading to a much longer rod life time than in conventional shunting arc or peripheral arc. The shunting-arc-produced plasma contains mainly the ions of the solid-state material, and ion extraction from the plasma has also been demonstrated. Thus, the shunting arc works as a pulsed ion source for solid-state materials for plasma-based ion implantation (PBII) and ion processing. This article describes the characteristics of pulsed shunting arc, using the materials of carbon, niobium and silicon. The capacitor of 10 nF of which charging voltage is 10 to 25 kV using a thyratron as a closing switch. Glow discharge is firstly produced after the heat of the materials and then the plasma changes the style to the arc discharge. A negative high voltage pulse of -5 to -10 kV was applied to a target which was located at 30 cm away from the electrodes. We will discuss the ion species of the shunting plasma and ion extraction from the plasma using the time evolution of target current.

  3. Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in A Child: A Case Report

    Babak ABDINIA


    Full Text Available How to Cite This Article: Abdinia B, Barzegar M, Maleki M, Behbod H, Oskoui Sh. Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in a Child: a Case Report. Iran J Child Neurol. 2013 Winter:7(1:35-38. Brucellosis is an endemic zoonosis in Iran. It is a systemic infection that can involve any organs or systems of the body and have variable presentations. Ventriculoperitoneal (VP shunt infections due to brucellosis have been rarely reported in the literatures.This  is  the  history  of  a  four  years  old  boy  who  developed  Brucella meningoencephalitis at the age of 42 months, whilst he had a VP shunt in situ for hydrocephalus treatment. Also, he presented brucellosis as acute abdomen. This patient was treated with trimethoprim-sulfamethoxazole, gentamicin and rifampicin. The shunt was extracted and all clinical and laboratory test abnormalities subsided through this management.We propose that in a patient with Brucella meningoencephalitis, the cerebrospinal  fluid shunt  system  can  be  extracted  and  treatment  with appropriate combination of antibiotics could be successful. Moreover, it shows that brucellosis should be considered in the differential diagnosis for acute abdomen and ascites in endemic regions.References1. Hasanjani Roushan MR, Mohrez M, Samilnejad Gangi SM, Soleimani Amiri MJ, Hajiahmadi M. Epidemiological features and clinical manifestations in 469 adult patients with brucellosis in babol, Northern Iran. Epidemiol infect 2004;132(6:1109-142. Bouza E, García de la Torre M, Parras F, Guerrero A, Rodríguez-Créixems M, Gobernado J. Brucellar meningitis. Brucellar meningitis. Rev Infect Dis 1987; 9(4:810-22.3. Young EJ. Brucella species. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas and Bennetts Õs Principles and Practice of Infectious Diseases. 5th ed. New York: Churchill Livingstone; 2000. p. 86-93.4. Feiz J, Sabbaghian H, Miralai M. Brucellosis due to Brucella

  4. Multiple Chaotic Central Pattern Generators with Learning for Legged Locomotion and Malfunction Compensation

    Ren, Guanjiao; Chen, Weihai; Dasgupta, Sakyasingha


    on a simulated annealing algorithm. In a normal situation, the CPGs synchronize and their dynamics are identical. With leg malfunction or disability, the CPGs lose synchronization leading to independent dynamics. In this case, the learning mechanism is applied to automatically adjust the remaining legs...... chaotic CPG controller has difficulties dealing with leg malfunction. Specifically, in the scenarios presented here, its movement permanently deviates from the desired trajectory. To address this problem, we extend the single chaotic CPG to multiple CPGs with learning. The learning mechanism is based...... in a physical simulation of a quadruped as well as a hexapod robot and finally in a real six-legged walking machine called AMOSII. The experimental results presented here reveal that using multiple CPGs with learning is an effective approach for adaptive locomotion generation where, for instance, different body...

  5. Immune malfunction in the GPR39 zinc receptor of knockout mice

    Młyniec, Katarzyna; Trojan, Ewa; Ślusarczyk, Joanna


    as an anti-inflammatory agent, and its link with depression has been proved, zinc deficiency causing depression- and anxiety-like behavior with immune malfunction. It has been discovered that trace-element zinc acts as a neurotransmitter in the central nervous system via zinc receptor GPR39. In this study we...... investigated whether GPR39 knockout would cause depressive-like behavior as measured by the forced swim test, and whether these changes would coexist with immune malfunction. In GPR39 knockout mice versus a wild-type control we found: i) depressive-like behavior; ii) significantly reduced thymus weight; (iii......Depression is a serious psychiatric disorder affecting not only the monaminergic, glutamatergic, and GABAergic neurosystems, but also the immune system. Patients suffering from depression show disturbance in the immune parameters as well as increased susceptibility to infections. Zinc is well known...

  6. Reducing CSF shunt placement in patients with spinal myelomeningocele

    Suresh Sankhla


    Full Text Available Object: The incidence of hydrocephalus requiring shunts in children with myelomeningocele (MMC is reported to be very high. Shunt-related complications are a significant cause of morbidity and mortality in this population. In order to minimize shunt placements, we used very rigid clinical selection criteria and followed them in all patients who had myelomeningocele and enlarged ventricles. The follow-up outcome of this retrospective study is reported. Methods: From 2000 to 2007, 23 patients with myelomeningocele and variable degree of hydrocephalus were treated at our institute with primary surgical closure of their myelomeningoceles without a CSF diversion procedure. Patients with severe hydrocephalus who required immediate shunt insertion, and those with no significant associated hydrocephalus were not included in this study. Data regarding the surgical results and complications, postoperative management, and the outcome at follow-up were obtained from their hospital records. Results: Initially increased size of the ventricular system was found to have decreased or stabilized in 17 (81% patients postoperatively. However, ventriculomegaly continued to progress further in 4 (19% out of 21 patients. Of 11 patients who presented with enlarged head, eight (73% patients showed reduction or stabilization in their head circumference. Three (27% children continued to have progressive head enlargement in the postoperative period and required shunt placement. Signs of raised intracranial pressure observed in six patients on admission, improved in two (33% and persisted or worsened in four (67% patients who eventually improved after the insertion of a shunt. Eight (35% patients experienced wound-related complications following closure of the MMC, including CSF leak in four, wound infection in three, wound breakdown in three, and pseudomeningocele in two patients. Shunt placement was required in the postoperative period in 13 (56.5% patients to treat

  7. Intrahepatic arterioportal shunt: helical CT findings

    Quiroga, S.; Sebastia, M.C.; Moreiras, M.; Pallisa, E.; Rius, J.M.; Alvarez-Castells, A. [I. D. I. Hospital General i Universitari Vall d`Hebron, Barcelona (Spain). Servei de Radiodiagnostic


    The purpose of this study was to characterize the appearance of intrahepatic arterioportal shunts (APS) on two-phase helical CT, with emphasis on the importance of the hepatic arterial-dominant phase (HAP) to demonstrate perfusion disorders. We review eight cases of APS diagnosed by helical CT in our institution from January 1996 to March 1997 and describe the CT findings that established diagnosis. Five of them were confirmed by angiography. In seven (87.5 %) cases of APS we found early enhancement of the peripheral portal branches during the HAP of helical CT, whereas the superior mesenteric and splenic veins remained unenhanced. In five (62.5 %) cases of APS, transient, peripheral, triangular parenchymal enhancement was depicted during the HAP of helical CT; in four of these cases there was associated early enhancement of the portal branches. Helical CT can show perfusion alterations that might remain undiagnosed with conventional CT. An understanding of the hemodynamic changes that occur in APS can help in the interpretation of focal transient hepatic parenchymal enhancement and to differentiate APS from hypervascular tumors. We believe that the helical CT findings described herein are characteristic enough to suggest the diagnosis of APS. (orig.) With 3 figs., 1 tab., 16 refs.

  8. An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions

    Kowalski Jerzy


    Full Text Available The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.

  9. [Scintigraphic imaging in the diagnosis of failed intrathecal baclofen therapy: a case report of a 7-year-old boy with ventriculoperitoneal shunt].

    Shibata, Akiko; Yamamoto, Mariko; Watanabe, Yu; Terashima, Hiroshi; Kashii, Hirofumi; Kubota, Masaya; Morota, Nobuhito


    Intrathecal baclofen (ITB) therapy is popular for the management of intractable spasticity. In 2007, the indications of ITB therapy expanded to include spasticity of children in Japan. In this report, we assessed the utility of radioisotopic scintigraphy in the diagnosis of failed ITB therapy. A 7-year-old boy with schizencephaly, hydrocephalus, and spastic quadriplegia had an ITB pump implanted. In his infancy, he had undergone ventriculoperitoneal shunt implantation. One month after the ITB operation, the ITB therapeutic effect diminished. Several examinations confirmed that the pump function was normal and catheter failure had not occurred. However, radioisotopic scintigraphy revealed that the baclofen had been washed out to blood circulation more rapidly than is typically observed. We considered two possible causes for this; obstruction of the cerebrospinal space due to kyphosis and excessive washout of celebrospinal fluid through the ventriculoperitoneal shunt. The catheter was moved to a more caudal site surgically, and his spasticity improved. The use of radioisotopic scintigraphy to identify the distribution of baclofen is an effective technique for investigation of baclofen pump system malfunction.

  10. Effects of prone position ventilation combined with recruitment maneuver on oxygenation and intrapulmonary shunt in canines with acute respiratory distress syndrome%俯卧位通气联合肺复张手法对急性呼吸窘迫综合征犬氧合及肺内分流的影响

    许启霞; 詹庆元; 王辰; 庞宝森; 李一鸣


    2.75、2.99,P均<0.05).结论 在小潮气量+呼气末正压的肺保护性通气基础上,俯卧位通气联合肺复张手法可以更有效地改善氧合,减少分流.%Objective To evaluate the effects of prone position ventilation(PPV)combined with recruitment maneuver(RM) on oxygenation and intrapulmonary shunting in oleic acid-induced acute respiratory distress syndrome(ARDS)in canines while ventilated with lung protective ventilation strategy.Methods ARDS was induced by oleic acid in 24 dogs,and the animals were ventilated with volume controlled ventilation(VCV),16 em H2O(1 cm H2O:0.098 kPa)of positive end-expiratory pressure(PEEP)and small tidal volumes(VT 10 ml/kg).All the dogs were randomly divided by random digit table into 4 groups(6 each),a control group(supine position,SP group),a prone position group(PP group),a supine position+RM group(SPRM group),and a prone position+RM group(PPRM group),and then were ventilated by VCV for 4 h.Arterial and mixed venous blood gas analyses were measured.Data were analyzed using the SPSS for windows(version 11.5).Results were expressed as (-x) ±s.Homogeneity of variance test was performed.The differences in means were calculated using one-way ANOVA.Post-hoc multiple comparisons of means were performed using Least Significant Difference.Nonparametric tests for several independent samples were performed to compare differences between the ranks in the groups studied.P value of<0.05 was considered statistically significant.Results (1) At 15 min,PaO2/FiO2 in the SPRM group,the PP group and the PPRM group[(368±45)mm Hg(1 mm Hg=0.133 kPa),(349±80)mm Hg,(423±43)mm Hg,respectively] was significantly higher than that in the SP group[(269±72)mm Hg,q=2.77,2.23,4.31,respectively,all P<0.05].At 2 h,PaO2/FiO2 in the PP group and the PPRM group[(401±82)mm Hg,(416±23)mm Hg,respectively] was significantly higher than that in the SP group[(232±40)mm Hg,q=3.99,4.35,respectively,all P<0.05].At 4 h,PaO2/FiO2 in the PPRM group[(384

  11. Shunt insufficiency due to knot formation in the peritoneal catheter.

    Fekete, Gábor; Nagy, Andrea; Pataki, István; Bognar, László; Novák, László


    The authors report a rare case of the peripheral obstruction of a ventriculoperitoneal shunt. Premature baby was operated on hydrocephalus due to germinal matrix bleeding. After two months of implantation of venticuloperitoneal shunt peripheral insufficiency of the system was emerged. During the shunt revision extensive knot formation became visible. We simply cut the catheter above the knot and the working shunt was replaced into the abdominal cavity. The postoperative course was uneventful and the baby was free of complaints for more than one year. The pathomechanism of knot formation is not clear thus the discovery of the problem during the operation is an unexpected event. In our opinion tight knot cannot be spontaneously formed intraabdominally. Loose knots can be developed and can reduce the capacity of liquor flow. We think that the knot tightens during pulling out. Longer peritoneal catheters can precipitate multiple looping and/or axial torquations and increase the peripheral resistance of the shunt. In such cases when the pulling out is challenged conversion to laparotomy is suggested.

  12. Laparoscopy for ventriculoperitoneal shunt implantation and revision surgery

    Fernando; Campos; Gomes; Pinto; Matheus; Fernandes; de; Oliveira


    Ventriculoperitoneal shunting(VPS) is a widely accepted technique for the treatment of hydrocephalus. The probability of shunt dysfunction is pretty high throughout life. Laparoscopy has become a valuable tool to perform VPS and treat abdominal complications. An electronic literature search was performed to reveal the published data relating laparoscopy and ventriculoperitoneal shunt in Medline, Embase, Scielo and Lilacs databases. The keywords employed were “laparoscopy” OR “laparoscopic surgery” AND “ventriculoperitoneal shunt” OR “shunt” AND “surgery” OR “implantation” OR “revision” OR “complication”. No high quality trials were developed comparing conventional laparotomic incision vs laparoscopic approach. Both approaches have evolved and currently there are less invasive options for laparotomy, like periumbilical small incisions; and for laparoscopy, like smaller and less incisions. Operating room time, blood loss and hospital stay may be potentially smaller in laparoscopic surgery and complications are probably the same as laparotomy. In revision surgery for abdominal complications after VPS,visualization of whole abdominal cavity is fundamental to address properly the problem and laparoscopic approach is valuable once it is safe, fast and much less invasive than laparotomy. Ventriculoperitoneal shunting is a widely accepted technique for the treatment of hydrocephalus. Laparoscopy assisted shunt surgery in selected cases might be a less invasive and more effective option for intrabdominal manipulation. The laparoscopic approach allows a better catheter positioning, lysis of fibrotic bundles and peritoneal inspection as well, without any additional complication.

  13. Model of Shunting Technology Based on System Structure

    Anton Pepevnik


    Full Text Available Railway transport is facing a growing liquidity problem.The major problem in small systems is the detention of wagonsat marshalling yards, which prolongs the time of freight travel.To avoid this problem it is of great importance to search for parametersthat would enable creation of a model of technologythat would provide shorter wagon detention time at stations aswell as optimising the number of marshalling yards for smallsystems. It is at the same time a great opportunity to search for alink between the shunting work in the railway transport and thetheoretical system approach which presents it as a current scientificproblem. In classical technology the shunting work iscarried out with no application of and no regard for the systemapproach. With new shunting systems in the railway transportthe regard for theory of transport systems is crucial as the secondarylevel of classical methods.As already pointed out, from the theoretical point of viewan important contribution will be made to the use of system theoryfor shunting purposes, since the suggested model effectivelyprovides the approach of analysing separate elements in therailway transport structure into integral shunting operations atthe railway stations.

  14. Favorable results with syringosubarachnoid shunts for treatment of syringomyelia.

    Tator, C H; Meguro, K; Rowed, D W


    From 1969 to 1979, 20 patients with syringomyelia were treated with a syringosubarachnoid shunt. The principal indications for this procedure were: significant progressive neurological deterioration and absent or minimal tonsillar ectopia. There were 15 patients with idiopathic syringomyelia, four with posttraumatic syringomyelia, and one with syringomyelia secondary to spinal arachnoiditis. The operations were performed with an operating microscope, and attention was directed to preserving thearachnoid membrane to ensure proper placement of the distal end of the shunt in an intact subarachnoid space. In all cases, a silicone rubber ventricular catheter was inserted into the syrinx through a posterior midline myelotomy. The average follow-up period was 5 years. A favorable result was obtained in 15 of the 20 patients (75%), including an excellent result with improvement of neurological deficit in 11 patients and a good result with cessation of progression in four patients. In the remaining five patients the result was poor with further progression of neurological deficit. A short duration of preoperative symptoms was usually a favorable prognostic feature. Four patients with a history of less than 6 months all had excellent results. Thirteen patients had a syringosubarachnoid shunt only, and all had good or excellent results. Seven patients had other surgical procedures, before, accompanying, or after shunt placement, and two had favorable results. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for many patients with syringomyelia, particularly if there is little or no tonsillar herniation.

  15. Balloon-occluded retrograde transvenous obliteration for gastric variceal bleeding: its feasibility compared with transjugular intrahepatic portosystemic shunt

    Choi, Young Ho; Yoon, Chang Jin; Park, Jae Hyung; Chung, Jin Wook; Kwon, Jong Won [Seoul Natioonal University College of Medicine, Seoul (Korea, Republic of); Choi, Guk Myung [Cheju National University College of Medicine, Jeju (Korea, Republic of)


    To assess the feasibility of balloon-occluded retrograde transvenous obliteration (BRTO) in active gastric variceal bleeding, and to compare the findings with those of transjugular intrahepatic portosystemic shunt (TIPS). Twenty-one patients with active gastric variceal bleeding due to liver cirrhosis were referred for radiological intervention. In 15 patients, contrast-enhanced CT scans demonstrated gastrorenal shunt, and the remaining six (Group 1) underwent TIPS. Seven of the 15 with gastrorenal shunt (Group 2) were also treated with TIPS, and the other eight (Group 3) underwent BRTO. All patients were followed up for 6 to 21 (mean, 14.4) months. For statistical inter-group comparison of immediate hemostasis, rebleeding and encephalopathy, Fisher's exact test was used. Changes in the Child-Pugh score before and after each procedure in each group were statistically analyzed by means of Wilcoxon's signed rank test. One patient in Group 1 died of sepsis, acute respiratory distress syndrome, and persistent bleeding three days after TIPS, while the remaining 20 survived the procedure with immediate hemostasis. Hepatic encephalopathy developed in four patients (one in Group 1, three in Group 2, and none in Group 3); one, in Group 2, died while in an hepatic coma 19 months after TIPS. Rebleeding occurred in one patient, also in Group 2. Except for transient fever in two Group-3 patients, no procedure-related complication occurred. In terms of immediate hemostasis, rebleeding and encephalopathy, there were no statistically significant differences between the groups (p > 0.05). In Group 3, the Child-Pugh score showed a significant decrease after the procedure (p = 0.02). BRTO can effectively control active gastric variceal bleeding, and because of immediate hemostasis, the absence of rebleeding, and improved liver function, is a good alternative to TIPS in patients in whom such bleeding, accompanied by gastrorenal shunt, occurs.

  16. [Usefulness of IPC continuous monitoring in shunt dysfunction].

    Horcajadas, A; Román, A; Olivares, G; Saura, E; Jorques, A; Cordero, N; Ibáñez, B; Sánchez, C; Roldán, M A


    Shunt dysfunction is a common situation in neurosurgery. Often symptoms, physical examination and radiology are not enough to set a diagnosis. ICP continuous monitoring is a safe and reliable tool that provides valuable information about CSF dynamics in these patients. Not only quantitative analysis is needed but also a qualitative one that enables pathological waves identification, because high amplitude B waves are strongly related to shunt dysfunction. In this paper experience about ICP continuous monitoring in patients with shunt dysfunction suspect is presented. Quantitative and qualitative data analysis led to a correct diagnosis, improving all the patients treated according to this criterion. An intraparenchymatous Camino® sensor and neuroPICture software (developed by first author) for data collection and graphic representation were used. Complications related to monitoring were absent and graphics obtained useful for qualitative analysis.

  17. The Behaviour of Mistuned Piezoelectric Shunt Systems and Its Estimation

    M. Berardengo


    Full Text Available This paper addresses monoharmonic vibration attenuation using piezoelectric transducers shunted with electric impedances consisting of a resistance and an inductance in series. This type of vibration attenuation has several advantages but suffers from problems related to possible mistuning. In fact, when either the mechanical system to be controlled or the shunt electric impedance undergoes a change in their dynamical features, the attenuation performance decreases significantly. This paper describes the influence of biases in the electric impedance parameters on the attenuation provided by the shunt and proposes an approximated model for a rapid prediction of the vibration damping performance in mistuned situations. The analytical and numerical results achieved within the paper are validated using experimental tests on two different test structures.

  18. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    Er, Uygur; Akyol, Çetin; Bavbek, Murad


    Aim of this paper is to present and discuss a case of a delayed cerebellar parenchymal hemorrhage developing after L/P shunt placement with a NPH patient. A hypertensive patient admitted to our clinic with a diagnosis of NPH. The patient was placed a pressure adjustable L/P shunt without any surgical complication. He was discharged with an uneventful period. The patient was admitted to the emergency clinic of our hospital with a 1.5 × 1.5 cm diameter hematoma at the left cerebellar hemisphere on 2 days after his discharge. CSF drainage by an L/P shunt can generate intracerebellar hemorrhages especially in hypertensive patients. PMID:27695558

  19. Cerebrospinal fluid galactorrhea: a rare complication of ventriculoperitoneal shunting.

    Lee, Sai-Cheung; Chen, Jyi-Feng; Tu, Po-Hsun; Lee, Shih-Tseng


    In this report we describe a 26-year-old woman who had an intra-abdominal pseudocyst located at the peritoneal catheter tip following ventriculo-peritoneal (VP) shunt implantation. Retrograde cerebrospinal fluid (CSF) flowed outside the catheter and communicated with the right breast lactiferous ductal system and leaked from the nipple orifice. CSF galactorrhea only occurs when the lactiferous duct is injured during VP shunt implantation, in combination with the formation of an intra-abdominal CSF pseudocyst prior to lactiferous duct healing. Leakage of CSF from the nipple orifice can be successfully treated by simply guiding the peritoneal catheter tip into the peritoneal cavity through a new laparotomy; that is, shunt revision is not always required.

  20. Portacaval shunt established in six dogs using magnetic compression technique.

    Xiaopeng Yan

    Full Text Available BACKGROUND AND AIMS: Installing the transjugular intrahepatic portosystemic shunt for portal hypertension is relatively safe, but complications are still high. To explore a new method of portacaval shunt, the magnetic compression technique was introduced into the shunting procedure. METHODS: A portal-inferior vena cava shunt was performed on 6 male mongrel dogs by two hemocompatible Nd-Fe-B permanent magnets, parent and daughter. The parent magnet was applied to the inferior vena cava guided by a catheter through the femoral vein. The daughter magnet was moved to the anastomosis position on the portal vein with a balloon catheter through the splenic vein. After the daughter magnet reached the target position, the two magnets acted to compress the vessel wall and hold it in place. Five to 7 days later, under X-ray guidance, the magnets were detached from the vessel wall with a rosch-uchida transjugular liver access set. One month later, histological analysis and portal venography were performed. RESULTS: 5-7 days after the first surgery, a mild intimal hyperplasia in the portal vein and the inferior vena cava, and continuity of the vascular adventitia from the portal vein to the inferior vena cava as observed. During the second surgery, the contrast media could be observed flowing from the portal vein into the inferior vena cava. Portal venography revealed that the portosystemic shunt was still present one month after the second surgery. CONCLUSIONS: Magnamosis via a device of novel design was successfully used to establish a portacaval shunt in dogs.

  1. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.


    Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

  2. Ventriculoperitoneal shunt complications in hydrocephalus patients with intracranial tumors: an analysis of relevant risk factors.

    Reddy, G Kesava; Bollam, Papireddy; Caldito, Gloria; Willis, Brian; Guthikonda, Bharat; Nanda, Anil


    Patients with intracranial tumors are predisposed to persistent hydrocephalus, often requiring a permanent CSF diversion procedure with shunts. This study reviews the long-term experience with ventriculoperitoneal shunts for the management of hydrocephalus in patients with intracranial tumors. Patients with intracranial tumors who underwent ventriculoperitoneal shunt placement for hydrocephalus from October 1990 to October 2009 were included in this study. During the 19-year period, medical charts, operative reports, imaging studies, and clinical follow- up evaluations were reviewed and analyzed retrospectively for all patients. A total of 187 intracranial tumor patients with hydrocephalus were included. The median follow up was 391 days. Malignant tumors were present in 40% of the patients. Overall shunt failure was 27.8%. Single shunt revision occurred in 13% of the patients and 14% had multiple shunt revision. Tumor histology, age and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Shunt system replacement and proximal shunt complication were significantly attributed to multiple shunt revisions. The overall shunt revision within 3 months, 6 months, 1 year and 5 years was 17.7%, 18.7%, 19.8% and 24.1%, respectively. The results of the study demonstrate that VP shunting is an effective for the management of hydrocephalus in patients with intracranial tumors. The overall incidence of shunt revision was 27.8%. Age, tumor histology, and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Additional studies using minimally invasive techniques are being explored for the management of hydrocephalus in patients with intracranial tumors.

  3. Rectal extrusion of the catheter and air ventriculography following bowel perforation in ventriculo-peritoneal shunt

    Arico, M.; Podesta, A.F.; Bianchi, E.; Beluffi, G.; Fiori, P.; Chiari, G.; Pezzotta, S.


    Ventriculo-peritoneal shunt is frequently carried out in infantile hydrocephalus. The peritoneal shunt has a lower morbidity than ventriculo-atrial shunt and severe complications are uncommon. Abdominal complications include intestinal perforation, shunt migration, inguinal hernia, cerebrospinal fluid pseudocysts and hollow viscus perforation. A few cases of catheter extrusion from the rectum, vagina, umbilicus and urethra have been described. We report a new case of intestinal perforation with rectal extrusion of the catheter associated with a ventriculogram.

  4. Treatment of Portosystemic Shunt Myelopathy with a Stent Graft Deployed through a Transjugular Intrahepatic Route

    Jain, Deepak, E-mail:; Arora, Ankur, E-mail: [Institute of Liver and Biliary Sciences, Department of Radiology (India); Deka, Pranjal, E-mail: [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India); Mukund, Amar, E-mail:; Bhatnagar, Shorav, E-mail: [Institute of Liver and Biliary Sciences, Department of Radiology (India); Jindal, Deepti, E-mail:; Kumar, Niteen, E-mail:; Pamecha, Viniyendra, E-mail: [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India)


    A case of surgically created splenorenal shunt complicated with shunt myelopathy was successfully managed by placement of a stent graft within the splenic vein to close the portosystemic shunt and alleviate myelopathy. To our knowledge, this is the first report of a case of shunt myelopathy in a patient with noncirrhotic portal fibrosis without cirrhosis treated by a novel technique wherein a transjugular intrahepatic route was adopted to deploy the stent graft.

  5. Measurement of shunt amount using radionuclide angiocardiography: accuracy according to level of shunt and associated lesion

    Kim, Yang Min [Sejong General Hospital, Bucheon (Korea, Republic of)


    Determination of pulmonary to systemic blood flow ratio (QP/QS) is important for the management of patients with left-to-right shunt. This study was performed to assess the agreement of Qp/Qs ratio using the radionuclide method and oxymetry, to investigate the factors influencing the agreement, and to know how interchangeable the results of each technique. We compared the Qp/Qs measured by single-pass radionuclide angiocardiography and oxymetry during catheterization in 207 patients who underwent both studies. In radionuclide method, Qp/Qs was calculated from the pulmonary time-activity curves using a gamma variate fit. The correlation and Bland-Altman analysis were performed according to the levels of shunt and associated lesions. The mean Qp/Qs was 1.83 {+-} 0.50 by radionuclide, and 1.74 {+-} 0.51 by oxymetry. The overall correlation coefficient was 0.86 ({rho} 0.001), and Bland-Altman range of agreement encompassing 4SD was 1.05. For atrial septal defect, ventricular septal defect, patent ductus arteriosus, tricuspid and mitral insufficiency, the correlation coefficient was 0.78, 0.90, 0.84, 0.63 and 0.44 and Bland-Altman range was 1.52, 0.74, 0.96, 1.57 and 1.50, respectively. There is good agreement but wide variance between the Qp/Qs ratios by radionuclide method and oxymetry. Associated atrioventricular valvar insufficiency decreases the correlation coefficient and widens the variance. Wide overall variance suggests that Qp/Qs measurements by two techniques should not be used interchangeably.

  6. Dynamic actuation methods for capacitive MEMS shunt switches

    Khater, M. E.; Vummidi, K.; Abdel-Rahman, E. M.; Nayfeh, A. H.; Raman, S.


    We develop dynamic actuation methods for capacitive MEMS shunt switches. We show that the dynamic actuation voltage is significantly less than the static actuation voltage and demonstrate 60% reduction in the actuation voltage. We also show that this reduction in the actuation voltage depends on the specific dynamic switching technique adopted. For a given operating condition, the minimum realizable switching time is that obtained using static switching. However, we developed a dynamic switching method that yields comparable switching time to that minimum. We also found that squeeze-film damping is the dominant damping mechanism for a shunt switch with a relatively slender bridge (aspect ratio of 11:1).

  7. Balanced calibration of resonant shunt circuits for piezoelectric vibration control

    Høgsberg, Jan; Krenk, Steen


    Shunting of piezoelectric transducers and suitable electric circuits constitutes an effective passive approach to resonant vibration damping of structures. Most common design concepts for resonant resistor-inductor (RL) shunt circuits rely on either maximization of the attainable modal damping...... series and parallel RL circuits. The procedure relies on equal modal damping and sufficient separation of the complex poles to avoid constructive interference of the two modes. By comparison with existing design procedures, it is demonstrated that the present calibration leads to a balanced compromise...

  8. Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique

    Teck M Soo


    Conclusions: Shunting procedures for the syringomyelia disease spectrum have been criticized due to the inconsistent long-term outcomes. This surgical technique used to treat symptomatic idiopathic syringomyelia has been devised based on our intraoperative experience, surgical outcomes, and evaluation of the literature. The purpose of the wedges is to preserve patency of the communication between the syrinx cavity and the expanded subarachnoid space by preventing healing of the myelotomy edges and by maintaining an artificial conduit between the syrinx cavity and the subarachnoid space. Although short-term results are promising, continued long-term follow up is needed to determine the ultimate success of the silastic wedge shunting procedure.

  9. Cryptococcal cerebrospinal fluid shunt infection treated with fluconazole

    Daniel Eymard


    Full Text Available A 37-year-old woman with a cadaveric renal allotransplantation required intra-cranial shunting devices after a presumptive episode of tuberculous meningitis. Six months later, she developed a culture-proven cryptococcal meningitis. Without having her ventriculo-auricular shunt removed, she was successfully treated with a short course of amphotericin B (335 mg and flucytosine (nine days followed by prolonged therapy with oral fluconazole (400 mg daily for 72 days. Three years post treatment she had no evidence of relapse, and normal renal graft function.

  10. CSF Ascites: Review of articles and a case presentation

    R Pourkhalili


    Full Text Available Cerebrospinal fluid (CSF ascites is a rare complication after ventriculopritoneal (VP shunts. Most patients have gradual abdominal protrusion without any neurological sign or symptom of shunt malfunction. We presented a girl with posterior third ventricle glioblastoma and acute hydrocephalus who developed increasingly abdominal protrusion one month after VP shunt operation. Ascites fluid examination showed characteristic findings similar to CSF with no evidence of infection or malignant cells. Ventriculo-atrial shunt revision cured patient's ascites. Review articles of patients with CSF ascites after VP shunt were presented in details. Key words: Cerebrospinal fluid, Ascites, Ventriculopritoneal Shunt

  11. Shoulder tip pain: an under-reported complication of ventriculoperitoneal shunt.

    Lim, C


    Ventriculoperitoneal (VP) shunt insertion is the commonest form of treatment for hydrocephalus. Shoulder tip pain after VP shunt insertion is unusual and has only recently been reported. We present a case of excruciating shoulder tip pain due to diaphragmatic irritation after VP shunt insertion.

  12. Management for traumatic chronic subdural hematoma patients with well-controlled shunt system for hydrocephalus.

    Yamada, Shoko Mitrrt; Tomia, Yusuke; Murakami, Hideki; Nakane, Makoto


    Traumatic CSDH enlarged in two cases with VP or LP shunt system although the shunt valve pressure was increased to 200 mmH2O. In surgery, the hematoma cavity pressure was found to be 130 and 140 mmH2O, suggesting that to raise the shunt valve pressure is not effective for decreasing CSDH volume.

  13. Ultrasonography of portosystemic shunting in dogs : Doppler studies before, during and after surgery

    Szatmári, V.


    Portosystemic shunting occurs when anomalous veins allow the portal blood to enter the systemic veins directly without first flowing through the hepatic sinusoids. Portosystemic shunting can occur via acquired portosystemic collaterals or via congenital portosystemic shunts and may result in clinica

  14. Perforation into gut by ventriculoperitoneal shunts: A report of two cases and review of the literature

    Abdul Hai


    Full Text Available We report two cases of gastrointestinal perforation by ventriculoperitoneal (VP shunts and review the literature on the topic. The time interval between shunt surgery and detection of bowel perforation is minimum in infants and increases with age. Sigmoid and transverse colon followed by stomach are the most frequent sites of gastrointestinal perforations by VP shunts.

  15. Locally Resonant Gaps of Phononic Beams Induced by Periodic Arrays of Resonant Shunts

    CHEN Sheng-Bing; WEN Ji-Hong; WANG Gang; HAN Xiao-Yun; WEN Xi-Sen


    @@ Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams.Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit.Therefore,the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam.However,the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far.In this work,the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment.The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.%Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams. Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit. Therefore, the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam. However, the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far. In this work, the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment. The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.




    Shunt nephritis is a rare complication of a chronically infected ventriculoatrial shunt. A 17 year old boy is described, with arthritis in both ankles and positive rheumatoid factor tests, who presented with symptoms of shunt nephritis. Blood cultures were positive for Staphylococcus epidermidis. Th

  17. Diagnosis of complications in ventriculo-peritoneal and ventriculo-atrial shunts. Diagnostik von Komplikationen ventrikuloperitonealer und ventrikuloatrialer Shunts

    Langen, H.J.; Alzen, G.; Avenarius, R. (Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik); Mayfrank, L. (Technische Hochschule Aachen (Germany). Klinik fuer Neurochirurgie); Thron, A. (Technische Hochschule Aachen (Germany). Neuroradiologie); Kotlarek, F. (Technische Hochschule Aachen (Germany). Kinderklinik)


    The value of imaging (cranial CT, cranial and abdominal sonography, plain film surveys) was examined retrospectively in 28 shunted children in whom 82 instances of suspected dysfunction arose. There were 23 obstructions, 12 dislocations, 1 disconnection, 6 infections, 3 overdrainages and 5 slit ventricle syndromes. Impaired absorption with ascites, a peritoneal liquor cyst and a seroma occurred in the peritoneal part of the shunt. Progressive dilatation of the ventricle system shown by CCT (89%) or ultrasound was the most sensitive sign of high-pressure hydrocephalus. Periventricular hypodensity and flattening of the gyri (15%) were found less often. An examination strategy in suspected shunt dysfunction is suggested on the basis of these findings. (orig.).

  18. Selective detection of mitochondrial malfunction in situ by energy transfer spectroscopy

    Schneckenburger, Herbert; Gschwend, Michael H.; Sailer, Reinhard; Strauss, Wolfgang S. L.; Schoch, Lars; Schuh, Alexander; Stock, Karl; Steiner, Rudolf W.; Zipfl, Peter


    To establish optical in situ detection of mitochondrial malfunction, non-radiative energy transfer from the coenzyme NADH to the mitochondrial marker rhodamine 123 (R123) was examined. Dual excitation of R123 via energy transfer from excited NADH molecules as well as by direct absorption of light results in two fluorescence signals whose ratio is a measure of mitochondrial NADH. These signals are detected simultaneously using a time-gated (nanosecond) technique for energy transfer measurements and a frequency selective technique for direct excitation and fluorescence monitoring of R123. Optical and electronic components of the experimental setup are described and compared with a previously established microscopic system.

  19. An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine with Fuel Injector Malfunctions

    Kowalski Jerzy


    The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant spee...

  20. Human Errors - A Taxonomy for Describing Human Malfunction in Industrial Installations

    Rasmussen, J.


    This paper describes the definition and the characteristics of human errors. Different types of human behavior are classified, and their relation to different error mechanisms are analyzed. The effect of conditioning factors related to affective, motivating aspects of the work situation as well...... as physiological factors are also taken into consideration. The taxonomy for event analysis, including human malfunction, is presented. Possibilities for the prediction of human error are discussed. The need for careful studies in actual work situations is expressed. Such studies could provide a better...... understanding of the complexity of human error situations as well as the data needed to characterize these situations....

  1. NH4+ triggers the release of astrocytic lactate via mitochondrial pyruvate shunting

    Lerchundi, Rodrigo; Fernández-Moncada, Ignacio; Contreras-Baeza, Yasna; Sotelo-Hitschfeld, Tamara; Mächler, Philipp; Wyss, Matthias T.; Stobart, Jillian; Baeza-Lehnert, Felipe; Alegría, Karin; Weber, Bruno; Barros, L. Felipe


    Neural activity is accompanied by a transient mismatch between local glucose and oxygen metabolism, a phenomenon of physiological and pathophysiological importance termed aerobic glycolysis. Previous studies have proposed glutamate and K+ as the neuronal signals that trigger aerobic glycolysis in astrocytes. Here we used a panel of genetically encoded FRET sensors in vitro and in vivo to investigate the participation of NH4+, a by-product of catabolism that is also released by active neurons. Astrocytes in mixed cortical cultures responded to physiological levels of NH4+ with an acute rise in cytosolic lactate followed by lactate release into the extracellular space, as detected by a lactate-sniffer. An acute increase in astrocytic lactate was also observed in acute hippocampal slices exposed to NH4+ and in the somatosensory cortex of anesthetized mice in response to i.v. NH4+. Unexpectedly, NH4+ had no effect on astrocytic glucose consumption. Parallel measurements showed simultaneous cytosolic pyruvate accumulation and NADH depletion, suggesting the involvement of mitochondria. An inhibitor-stop technique confirmed a strong inhibition of mitochondrial pyruvate uptake that can be explained by mitochondrial matrix acidification. These results show that physiological NH4+ diverts the flux of pyruvate from mitochondria to lactate production and release. Considering that NH4+ is produced stoichiometrically with glutamate during excitatory neurotransmission, we propose that NH4+ behaves as an intercellular signal and that pyruvate shunting contributes to aerobic lactate production by astrocytes. PMID:26286989

  2. Vascularização temporária de membros isquêmicos por meio de shunt arteriomedular: trabalho experimental Temporary vascularization on ischemic limbs through arterial-medullar shunt: an experimental work

    Ronaldo André Poerschke


    Full Text Available CONTEXTO: Os autores idealizaram um shunt temporário entre a artéria femoral e o canal medular de ossos longos para manter a viabilidade dos membros agudamente isquêmicos, enquanto não é possível estabelecer um tratamento definitivo. OBJETIVO: Avaliar a perviedade de shunts temporários arteriomedulares e a perfusão dos membros, durante duas horas em cães de experimentação, que tiveram a artéria femoral ligada. MÉTODOS: Alocaram-se aleatoriamente dois grupos, com três cães no Grupo Controle e seis no Grupo Intervenção. Os controles tiveram a artéria femoral comum direita ligada. O Grupo Intervenção, além da ligadura da artéria, recebeu um shunt. Após duas horas, realizou-se a medida de pH dos membros isquêmicos; avaliação do fluxo arterial por meio de um sonar Doppler; avaliação da coloração do sangramento na extremidade distal do membro e foram retirados em bloco torácico os pulmões para análise anatomopatológica. RESULTADOS: A média do pH do sangue capilar das extremidades do membros no Grupo Controle foi de 6,97 (±0,39; no Grupo Intervenção o pH foi de 7,25 (±0,46, com pBACKGROUND: The authors idealized a temporary shunt between the femoral artery and the medullar canal on long bones to keep the viability of acutely ischemic limbs, while waiting for a definitive treatment. OBJECTIVE: To assess the flow on temporary shunts between the femoral artery and the marrow canal of the tibia during two hours in experimental dogs, which had the femoral artery interrupted. METHODS: Two groups with three dogs on the Control Group and six on the Intervention Group were allocated at random. The controls had the right femoral common artery interrupted. The Intervention Group received a shunt between the iliac external artery and the medullar canal of the right tibia in addition. After two hours, the measure of the pH, blood coloration, blood flow in sonar Doppler on the ischemic limbs were performed. The lungs were

  3. High-Flow Arterio-Hepatic Venous Shunt in Hepatocellular Carcinoma: Use of Multi-Electrode Radiofrequency for Shunt Obliteration

    Pua, Uei, E-mail: [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)


    Intra-tumoral arterio-hepatic venous shunting (AHVS) poses an impediment to transarterial chemoembolization of liver tumors. Not only does it present a potential hazard for systemic shunting and embolization, but also the altered flow dynamics may also result in poor delivery of drug/embolics to the target tumor bed. Current available techniques to overcome AVHS include arterial embolization (particles, coils, glue, etc.) or temporary venous occlusion using balloons. We hereby illustrate the use of radiofrequency ablation to obliterate a complex AHVS consisting of a varix-like venous aneurysm.

  4. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists

    Taslakian, Bedros, E-mail: [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Faraj, Walid, E-mail: [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Khalife, Mohammad, E-mail: [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Al-Kutoubi, Aghiad, E-mail: [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); El-Merhi, Fadi, E-mail: [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Saade, Charbel, E-mail: [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Hallal, Ali, E-mail: [Department of General Surgery, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Haydar, Ali, E-mail: [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon)


    Highlights: • Portal hypertension is the pathological increase in portal venous pressure. • Surgical portosystemic shunting is an accepted methods to decrease portal venous pressure. • Surgical portosystemic shunts are divided into selective and nonselective. • Shunt thrombosis is a serious complication, resulting in shunt dysfunction. • Imaging is essential in the assessment of the shunt function and anatomy. - Abstract: Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

  5. Metabolic responses to moderate exercise in lambs with aortopulmonary shunts

    Beaufort-Krol, GCM; Takens, J; Zijlstra, WG; Molenkamp, MC; Gerding, AM; Kuipers, JRG


    In a previous study we found, after an overnight fast of 18 hours, a lower arterial glucose concentration and a depressed glycogenolysis in lambs with aortopulmonary left-to-right shunts. During exercise, glucose and free fatty acids (FFA) concentrations normally increase. The aim of this study was

  6. Congenital extrahepatic portosystemic shunt associated with heterotaxy and polysplenia

    Newman, Beverley [Lucile Packard Children' s Hospital, Department of Radiology, Stanford University School of Medicine, Stanford, CA (United States); Feinstein, Jeffrey A. [Stanford University School of Medicine, Division of Pediatric Cardiology, Department of Pediatrics, Lucile Packard Children' s Hospital, Stanford (United States); Cohen, Ronald A.; Patel, Hitendra [Children' s Hospital and Research Center, Department of Diagnostic Radiology, Oakland, CA (United States); Feingold, Brian; Kreutzer, Jacqueline [Children' s Hospital of Pittsburgh, Department of Pediatrics, Division of Pediatric Cardiology, Pittsburgh, PA (United States); Chan, Fandics P. [Stanford University School of Medicine, Cardiovascular Imaging Section, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)


    Heterotaxy with polysplenia is associated with many cardiovascular anomalies including the occasional occurrence of congenital extrahepatic portosystemic shunts (CEPS). Missing this anomaly can lead to inappropriate and ineffective therapy. To emphasize the importance and associated anatomy of CEPS in conjunction with heterotaxy with polysplenia. Review of three young children who presented with cyanosis and pulmonary hypertension without a cardiac etiology. They were known (1) or discovered (2) to have heterotaxy with polysplenia. There was absence of the intrahepatic inferior vena cava (IVC) with azygos or hemiazygos continuation in all three cases. In spite of normal liver function, they were discovered to have large portosystemic shunts, splenorenal in location, along with diffuse peripheral pulmonary arterial dilatation suggestive of CEPS (Abernethy malformation) with hepatopulmonary or, more accurately, portopulmonary syndrome. All CEPS were ipsilateral to the spleens. Patency of the portal veins in these cases allowed for percutaneous shunt closure with resolution of cyanosis. CEPS is associated with heterotaxy with polysplenia and can be symptomatic because of pulmonary arteriovenous (AV) shunting. Portal and hepatic vein patency are critical for determining feasibility of CEPS closure. (orig.)

  7. Wideband digital phase comparator for high current shunts

    Pogliano, Umberto; Serazio, Danilo


    A wideband phase comparator for precise measurements of phase difference of high current shunts has been developed at INRIM. The two-input digital phase detector is realized with a precision wideband digitizer connected through a pair of symmetric active guarded transformers to the outputs of the shunts under comparison. Data are first acquired asynchronously, and then transferred from on-board memory to host memory. Because of the large amount of data collected the filtering process and the analysis algorithms are performed outside the acquisition routine. Most of the systematic errors can be compensated by a proper inversion procedure. The system is suitable for comparing shunts in a wide range of currents, from several hundred of milliampere up to 100 A, and frequencies ranging between 500 Hz and 100 kHz. Expanded uncertainty (k=2) less than 0.05 mrad, for frequency up to 100 kHz, is obtained in the measurement of the phase difference of a group of 10 A shunts, provided by some European NMIs, using a digit...

  8. Comparison of passive inductor designs for piezoelectric shunt damping

    Lossouarn, Boris; Thierry, Olivier; Aucejo, Mathieu; Deü, Jean-François


    Considering piezoelectric damping, a resonant shunt can lead to a significant vibration reduction when tuned to the mechanical mode to control. However, limits appear when looking at practical applications in a low frequency range: the required inductance is often too high to be satisfied with standard passive components. Moreover, even if the inductor is eventually available, the internal resistance of the component generally exceeds the value which is required for a shunt optimization. Suitable inductors can be designed for applications requiring high inductance and low resistance values. Indeed, the permeance of a magnetic circuit can be significantly increased by the use of closed cores made of high permeability materials. In this paper, three designs are described and compared: an inductor from standard series and two handmade inductors involving a ferrite core and a nanocrystalline toroid. The components are successively integrated into a piezoelectric shunt dedicated to the vibration control of a cantilever beam. Depending on the frequency of the target mechanical mode to control, the benefits and the limits of the different inductors are observed. It is shown that custom designs can definitely extend to lower frequency the application of the passive resonant shunt strategy.

  9. Small-Diameter PTFE Portosystemic Shunts: Portocaval vs Mesocaval

    Robert Shields


    Full Text Available Fifty-seven patients with failed sclerotherapy received a mesocaval interposition shunt with an externally supported, ringed polytetrafluoroethylene prosthesis of either 10 or 12 mm diameter. Thirty-one patients had Child-Pugh gradeA disease and 26 grade B; all had a liver volume of 1000– 2500 ml. Follow-up ranged from 16 months to 6 years 3 months. Three patients (5 per cent died in the postoperative period. There were two postoperative recurrences of variceal haemorrhage and one recurrent bleed in the second year after surgery. The cumulative shunt patency rate was 95 per cent and the incidence of encephalopathy 9 per cent; the latter was successfully managed by protein restriction and/or lactulose therapy. The actuarial survival rate for the whole group at 6 years was 78 per cent, for those with Child-Pugh grade A 88 per cent and for grade B 67 per cent. Small-lumen mesocaval interposition shunting achieves portal decompression, preserves hepatopetal flow, has a low incidence of shunt thrombosis, prevents recurrent variceal bleeding and is not associated with significant postoperative encephalopathy.

  10. Focally spared area of fatty liver caused by arterioportal shunt

    Arita, Takeshi; Matsunaga, Naofumi [Yamaguchi Univ. School of Medicine (Japan); Honma, Yutaka [Shimonoseki City Hospital, Yamaguchi (Japan)] [and others


    We describe a case with a focally spared area in fatty liver caused by arterioportal shunt. Furthermore, we discuss the cause of the focally spared area related to a localized dilution or reduction in portal blood flow. 13 refs., 1 fig.

  11. An Enhanced Data Visualization Method for Diesel Engine Malfunction Classification Using Multi-Sensor Signals

    Yiqing Li


    Full Text Available The various multi-sensor signal features from a diesel engine constitute a complex high-dimensional dataset. The non-linear dimensionality reduction method, t-distributed stochastic neighbor embedding (t-SNE, provides an effective way to implement data visualization for complex high-dimensional data. However, irrelevant features can deteriorate the performance of data visualization, and thus, should be eliminated a priori. This paper proposes a feature subset score based t-SNE (FSS-t-SNE data visualization method to deal with the high-dimensional data that are collected from multi-sensor signals. In this method, the optimal feature subset is constructed by a feature subset score criterion. Then the high-dimensional data are visualized in 2-dimension space. According to the UCI dataset test, FSS-t-SNE can effectively improve the classification accuracy. An experiment was performed with a large power marine diesel engine to validate the proposed method for diesel engine malfunction classification. Multi-sensor signals were collected by a cylinder vibration sensor and a cylinder pressure sensor. Compared with other conventional data visualization methods, the proposed method shows good visualization performance and high classification accuracy in multi-malfunction classification of a diesel engine.

  12. Pericardial effusion and cardiac tamponade after ventriculoperitoneal shunt placement: a case report.

    Wiwattanadittakul, Natrujee; Katanyuwong, Kamornwan; Jetjumnong, Chumpon; Sittiwangkul, Rekwan; Makonkawkeyoon, Krit


    Insertion of a ventriculoperitoneal shunt is a common neurosurgical procedure in both adult and paediatric patients. It is one of the most important treatments in cases of hydrocephalus; however, there is a wide range of complications: the most common complication being a shunt infection, and examples of rare complications are shunt migrations and cardiac tamponade. Several reports of distal ventriculoperitoneal shunt migration in different sites, including chest, right ventricle, pulmonary artery, bowel and scrotum were published. But pericardial effusion with cardiac tamponade and its relationship to distal ventriculoperitoneal shunt migration into the pericardial sac has never been reported.

  13. Pitfalls in the Performance and Interpretation of Scintigraphic Imaging for Pleuroperitoneal Shunt.

    Covington, Matthew F; Choudhary, Gagandeep; Avery, Ryan J; Kuo, Phillip H


    Ascites can cause pleural effusions when the peritoneal fluid crosses the diaphragm through a pleuroperitoneal shunt in the setting of hepatic cirrhosis (hepatic hydrothorax) or malignant ascites. Scintigraphic imaging for pleuroperitoneal shunt requires intraperitoneal injection of Tc-SC or Tc-macroaggregated albumin followed by planar imaging of the chest and abdomen. Pleuroperitoneal shunt is confirmed by identifying radiotracer crossing the diaphragm from the peritoneal to pleural space. An atlas of pleuroperitoneal shunt imaging pitfalls is presented to facilitate optimal performance and interpretation of nuclear pleuroperitoneal shunt examinations. Examples include cases of nondiagnostic radiotracer injections, processing errors, and nontarget uptake.

  14. Risk factors associated with distal catheter migration following ventriculoperitoneal shunt placement.

    Abode-Iyamah, Kingsley O; Khanna, Ryan; Rasmussen, Zachary D; Flouty, Oliver; Dahdaleh, Nader S; Greenlee, Jeremy; Howard, Matthew A


    Ventriculoperitoneal (VP) shunt placement is used to treat hydrocephalus. Shunt migration following VP shunt placement has been reported. The risk factors related to this complication have not been previously evaluated to our knowledge. In this retrospective cohort study, we aimed to determine risk factors leading to distal catheter migration and review the literature on the current methods of management and prevention. Adult patients undergoing VP shunt placement from June 2011 to December 2013 at a single institution were identified using electronic health records. The records were reviewed for demographic and procedural information, and subsequent treatment characteristics. The parameters of patients with distal shunt migration were compared to those undergoing new VP shunt placement for the same time period. We identified 137 patients undergoing 157 new VP shunt procedures with an average age of 57.7 ± standard deviation of 18.4 years old. There were 16 distal shunt migrations. Body mass index >30 kg/m(2) and number of previous shunt procedures were found to be independent risk factors for distal catheter migration. Obesity and number of previous shunt procedures were factors for distal catheter migration. Providers and patients should be aware of these possible risk factors prior to VP shunt placement.

  15. Control of an electromechanical hydrocephalus shunt--a new approach.

    Elixmann, Inga M; Kwiecien, Monika; Goffin, Christine; Walter, Marian; Misgeld, Berno; Kiefer, Michael; Steudel, Wolf-Ingo; Radermacher, Klaus; Leonhardt, Steffen


    Hydrocephalus is characterized by an excessive accumulation of cerebrospinal fluid (CSF). Therapeutically, an artificial pressure relief valve (so-called shunt) is implanted which opens in case of increased intracranial pressure (ICP) and drains CSF into another body compartment. Today, available shunts are of a mechanical nature and drainage depends on the pressure drop across the shunt. According to the latest data, craniospinal compliance is considered to be even more important than mean ICP alone. In addition, ICP is not constant but varies due to several influences. In fact, heartbeat-related ICP waveform patterns depend on volume changes in the cranial vessels during a heartbeat and changes its shape as a function of craniospinal compliance. In this paper, we present an electromechanical shunt approach, which changes the CSF drainage as a function of the current ICP waveform. A series of 12 infusion tests in patients were analyzed and revealed a trend between the compliance and specific features of the ICP waveform. For waveform analysis of patient data, an existing signal processing algorithm was improved (using a Moore machine) and was implemented on a low-power microcontroller within the electromechanical shunt. In a test rig, the ICP waveforms were replicated and the decisions of the ICP analysis algorithm were verified. The proposed control algorithm consists of a cascaded integral controller which determines the target ICP from the measured waveform, and a faster inner-loop integral controller that keeps ICP close to the target pressure. Feedforward control using measurement data of the patient's position was implemented to compensate for changes in hydrostatic pressure during change in position. A model-based design procedure was used to lay out controller parameters in a simple model of the cerebrospinal system. Successful simulation results have been obtained with this new approach by keeping ICP within the target range for a healthy waveform.

  16. Experimental comparison of piezoelectric and magnetostrictive shunt dampers

    Asnani, Vivake M.; Deng, Zhangxian; Scheidler, Justin J.; Dapino, Marcelo J.


    A novel mechanism called the vibration ring is being developed to enable energy conversion elements to be incorporated into the driveline of a helicopter or other rotating machines. Unwanted vibration is transduced into electrical energy, which provides a damping effect on the driveline. The generated electrical energy may also be used to power other devices (e.g., health monitoring sensors). PZT (`piezoceramic') and PMN-30%PT (`single crystal') stacks, as well as a Tb0.3Dy0.7Fe1.92 (`Terfenol-D') rod with a bias magnet array and a pickup coil, were tested as alternative energy conversion elements to use within the vibration ring. They were tuned for broadband damping using shunt resistors, and dynamic compression testing was conducted in a high-speed load frame. Energy conversion was experimentally optimized at 750Hz by tuning the applied bias stress and resistance values. Dynamic testing was conducted up to 1000Hz to determine the effective compressive modulus, shunt loss factor, internal loss factor, and total loss factor. Some of the trends of modulus and internal loss factor versus frequency were unexplained. The single crystal device exhibited the greatest shunt loss factor whereas the Terfenol-D device had the highest internal and total loss factors. Simulations revealed that internal losses in the Terfenol-D device were elevated by eddy current effects, and an improved magnetic circuit could enhance its shunt damping capabilities. Alternatively, the Terfenol-D device may be simplified to utilize only the eddy current dissipation mechanism (no pickup coil or shunt) to create broadband damping.

  17. Peroral extrusion of ventriculoperitoneal shunt: Case report and review of literature

    Sridhar K


    Full Text Available A rare complication of ventriculoperitoneal shunting (VPS is bowel perforation by the peritoneal catheter of the shunt tube. Rarer still is the peroral extrusion of such a perforated shunt. A two-month-old infant with history of neonatal meningitis, presented with a large head, bulging fontanelle, and hydrocephalus. A VPS was inserted. The child was doing well till the age of eight months, when following vomiting, the peritoneal end of the shunt came out through the mouth. The shunt was removed and antibiotics started. At follow up after 12 months, the child was doing well. Peroral extrusion of the shunt tube needs prompt treatment, including removal of the extruded shunt tube, and attention to bowel perforation and possible cerebrospinal fluid infection. The reported patient is younger than the five cases reported earlier. Strategies in the management of this complication are reviewed. An individualized approach is essential for the successful treatment of this rare complication.

  18. Shunt implantations and peritoneal catheters: Do not cut beyond 20 cm

    Angelo Luiz Maset


    Full Text Available Background: Ventriculoperitoneal shunts are supplied with long peritoneal catheters, most commonly between 80 and 120 cm long. ISO/DIS 7197/2006 [15] shunt manufacturing procedures include peritoneal catheter as an integrate of the total resistance. Cutting pieces of peritoneal catheters upon shunt implantation or revision is a common procedure. Methods: We evaluated five shunts assembled with different total pressure resistances and variable peritoneal catheter lengths in order to clarify the changes that occurred in the hydrodynamic profile when peritoneal catheters were cut upon shunt implantation or shunt revision. Results: Originally, all shunts performed within the operational range. Shunt 1 performed in a lower pressure range at 200 mm cut off peritoneal catheter and as a low-pressure shunt with -300 mm cut off. Shunt 2 was manufactured to run at the higher border pressure range, and it went out of specification with a 300 mm cut off. Shunt 3 was manufactured to run close to the lower border pressure range, and at 100 mm cutoff, it was already borderline in a lower resistive category. Other shunts also responded similarly. Conclusion: The limit to maintain a shunt in its original pressure settings was 20 cm peritoneal catheter cutting length. By cutting longer pieces of peritoneal catheter, one would submit patients to a less-resistive regimen than intended and his reasoning will be compromised. The pediatric population is more prone to suffer from the consequences of cutting catheters. Shunt manufacturers should consider adopting peritoneal catheters according to the age (height of the patient.

  19. An experimental in-vivo canine model for adult shunt infection

    Procop Gary


    Full Text Available Abstract Background Detailed human studies of the mechanisms and development of shunt infection in real time are not possible, and we have developed a canine hydrocephalus model to overcome this. The intention of this pilot study was to show that the canine hydrocephalus model could be shunted using conventional "human" shunts, and that a shunt infection could be established so that further studies could then be planned. Methods Hydrocephalus was induced in seven dogs (Canis familiaris by fourth ventricle obstruction. Four weeks later they were shunted using a Hakim Precision valve. Four of the dogs received shunts whose ventricular catheter had been inoculated with Staphylococcus epidermidis, and three were uninoculated controls. Four weeks after shunting the dogs were sacrificed and necropsy was performed. Removed shunts and tissue samples were examined microbiologically and isolates were subjected to detailed identification and genomic comparison. Results All the dogs remained well after shunting. Examination of removed shunt components revealed S. epidermidis in the brain and throughout the shunt system in the four inoculated animals, but in two of these Staphylococcus intermedius was also found. S. intermedius was also isolated from all three "negative" controls. There were slight differences between S. intermedius strains suggesting endogenous infection rather than cross- infection from a point source. Conclusion Shunt infection was established in the canine model, and had the experiment been extended beyond four weeks the typical microbiological, pathological and clinical features might have appeared. The occurrence of unplanned shunt infections in control animals due to canine normal skin flora reflects human clinical experience and underlines the usual source of bacteria causing shunt infection.

  20. Systemic-pulmonary artery shunts in infants: modified Blalock-Taussig and central shunt procedures.

    Brooks, Andre


    Access is gained through a midline sternotomy, the thymus partially excised and the superior part of the pericardium is opened. The innominate vein is retracted and the innominate artery is mobilized up to the bifurcation. The aorta is retracted to the left, the superior vena cavae to the right and the right atrial appendage inferiorly. The adventitia around the right pulmonary artery (PA) is dissected, taking care to incise the bulky pericardial reflection between the superior vena cavae and the trachea. Heparin is administrated. An occlusive clamp is applied to the right PA to test for haemodynamic tolerance prior to proceeding with the interposition of a suitable size artificial vascular prosthesis, based on the weight of the patient, between the innominate artery, or proximal subclavian artery and the right PA. Alternatively, if a sufficient main PA is present and adequate flow from a patent ductus arteriosus an end-to-side interposition shunt may be constructed between the ascending aorta and the main PA, provided the patient is stable with the test occlusion of the main PA. The management of the patent arterial ductus depends on whether or not there is forward flow through the PA.

  1. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    Gomez, Daniel R., E-mail: [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Pinnix, Chelsea C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sheu, Tommy [Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Memon, Nada [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rozner, Marc A. [Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dougherty, Anne H. [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)


    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  2. The orbital volume measurement in patients with ventriculoperitoneal shunt.

    Kim, Jong-Min; Chang, Moo-Hwan; Kyung, Sungeun E


    Enophthalmos occurs from the increased bony volume or decreased soft tissue volume in the orbit and can be caused in patients with long-term ventriculoperitoneal (VP) shunt. This study tried to find out the change of orbital volume by measuring the orbital volume before and after operation in adult patients who underwent VP shunt for hydrocephalus. The 2 evaluators measured orbital volume by using ITK-SNAP 2.4 program with double-blind test for computed tomography images before and after operation targeting 36 patients over the age of 18 who underwent VP shunt with pressure-controlled valve from 2003 to 2011. Wilcoxon matched-pairs signed-rank test of GraphPad software was used to statistically analyze the difference in orbital volume change before and after operation. In case of mean pre-op orbital volume of total 36 patients, the right was measured as 23.72 ± 4.65 cm(3), the left as 23.47 ± 4.61 cm(3), the post-op right as 24.67 ± 4.70 cm(3), and the left as 24.18 ± 4.63 cm(3), showing no statistically significant difference (P = 0.106). The mean pre-op orbital volume of 14 people (28 eyes) followed for more than 11 months was 25.06 ± 4.58 cm(3) in the right and 24.4 ± 5.02 cm(3) in the left and the mean post-op orbital volume was 27.0 ± 4.28 cm(3) in the right and 25.76 ± 3.92 cm(3) in the left, showing statistically significant differences in the change of the volume before and after shunt operation (P = 0.0057). In patients who maintain long-term shunt devices after VP shunt, remodeling of matured orbital bone may be caused due to the change in pressure gradient between cranial cavity and orbit and the possible occurrence of resulting secondary enophthalmos by increased orbital volume should be considered.

  3. Time-resolved in-situ measurement of mitochondrial malfunction by energy transfer spectroscopy

    Schneckenburger, Herbert; Gschwend, Michael H.; Strauss, Wolfgang S. L.; Sailer, Reinhard; Schoch, Lars; Schuh, Alexander; Stock, Karl; Steiner, Rudolf W.; Zipfl, Peter


    To establish optical in situ detection of mitochondrial malfunction, non-radiative energy transfer from the coenzyme NADH to the mitochondrial marker rhodamine 123 (R123) was examined. Dual excitation of R123 via energy transfer from excited NADH molecules as well as by direct absorption of light results in two fluorescence signals whose ratio is a measure of mitochondrial NADH. An experimental setup was developed, where these signals are detected simultaneously using a time-gated technique for energy transfer measurements and a frequency selective technique for direct excitation and fluorescence monitoring of R123. Optical and electronic components of the apparatus are described, and preliminary result of cultivated endothelial cells are reported. Results are compared with those obtained from a previously established microscopic system and discussed in view of potential applications.

  4. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists.

    Taslakian, Bedros; Faraj, Walid; Khalife, Mohammad; Al-Kutoubi, Aghiad; El-Merhi, Fadi; Saade, Charbel; Hallal, Ali; Haydar, Ali


    Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

  5. Ateriovenous subclavia-shunt for head and neck reconstruction

    Kübler Norbert R


    Full Text Available Abstract Reconstruction of the facial hard- and soft tissues is of special concern for the rehabilitation of patients especially after ablative tumor surgery has been performed. Impaired soft and hard tissue conditions as a sequelae of extensive surgical resection and/or radiotherapy may impede common reconstruction methodes. Even free flaps may not be used without interposition of a vein graft as recipient vessels are not available as a consequence of radical neck dissection. We describe the reconstruction of the facial hard- and soft tissues with a free parasacpular flap in a patient who had received ablative tumor surgery and radical cervical lymphadenectomy as a treatment regimen for squamous cell carcinoma (SCC. To replace the missing cervical blood vessels an arteriovenous subclavia-shunt using a saphena magna graft was created. Microvascular free flap transfer was performed as a 2-stage procedure two weeks after the shunt operation. The microvascular reconstructive technique is described in detail.

  6. Endoscopic third ventriculostomy has no higher costs than ventriculoperitoneal shunt

    Benicio Oton de Lima


    Full Text Available Objective: To evaluate the cost of endoscopic third ventriculostomy (ETV compared to ventriculoperitoneal shunt (VPS in the treatment of hydrocephalus in children. Method: We studied 103 children with hydrocephalus, 52 of which were treated with ETV and 51 with VPS in a prospective cohort. Treatment costs were compared within the first year after surgery, including subsequent surgery or hospitalization. Results: Twenty (38.4% of the 52 children treated with VPS needed another procedure due to shunt failure, compared to 11 (21.5% of 51 children in the ETV group. The average costs per patient in the group treated with ETV was USD$ 2,177,66±517.73 compared to USD$ 2,890.68±2,835.02 for the VPS group. Conclusions: In this series there was no significant difference in costs between the ETV and VPS groups.

  7. A Technique for Shunt Active Filter meld micro grid System

    A. Lumani


    Full Text Available The proposed system presents a control technique for a micro grid connected hybrid generation system ith case study interfaced with a three phase shunt active filter to suppress the current harmonics and reactive power present in the load using PQ Theory with ANN controller. This Hybrid Micro Grid is developed using freely renewable energy resources like Solar Photovoltaic (SPV and Wind Energy (WE. To extract the maximum available power from PV panels and wind turbines, Maximum power point Tracker (MPPT has been included. This MPPT uses the “Standard Perturbs and Observe” technique. By using PQ Theory with ANN Controller, the Reference currents are generated which are to be injected by Shunt active power filter (SAPFto compensate the current harmonics in the non linear load. Simulation studies shows that the proposed control technique performs non-linear load current harmonic compensation maintaining the load current in phase with the source voltage.\\

  8. Integrating rolling stock scheduling with train unit shunting

    Haahr, Jørgen Thorlund; Lusby, Richard Martin


    In this paper, we consider integrating two important railway optimization problems, in particular the Rolling Stock Scheduling Problem and the Train Unit Shunting Problem. We present two similar branch-and-cut based approaches to solve this integrated problem and, in addition, provide a comparison...... of different approaches to solve the so-called Track Assignment Problem, a subcomponent of the Train Unit Shunting problem. In this analysis we demonstrate, by way of a counter example, the heuristic nature of a previously argued optimal approach. For the integrated problem we analyze the performance...... of the proposed approaches on several real-life case studies provided by DSB S-tog, a suburban train operator in the greater Copenhagen area. Computational results confirm the necessity of the integrated approach; high quality solutions to the integrated problem are obtained on instances where a conventional...

  9. Transient Hemolytic Anemia after Transjugular Intrahepatic Portosystemic Stent Shunt

    Sagrario Garcia-Rebollo; Emilio González-Reimers; Francisco Santolaria-Fernández; Francisco Diaz-Romero; Fermin Rodriguez-Moreno; Antonio Martinez-Riera


    Management of variceal bleeding secondary to portal hypertension constitutes a challenging issue, particularly in child's C cirrhotic patients. Recently, transjugular placement of self-expanding metallic stents in the liver (TIPS), creating a shunt between the portal and hepatic branches has provided a safe and promising therapeutic approach in this clinical situation. We report here the case of a 66-year-old male cirrhotic patient who developed a moderately severe clinical picture of a Coomb...

  10. Pre-Liver Transplant: Tips Versus Distal Splenorenal Shunt

    Thomas W. Faust


    Full Text Available Recurrent variceal bleeding in liver transplant candidates with end-stage liver disease can complicate or even prohibit a subsequent transplant procedure (OLT. Endoscopic sclero-therapy and medical therapy are considered as first-line management with surgical shunts reserved for refractory situations. Surgical shunts can be associated with a high mortality in this population and may complicate subsequent OLT. The transjugular intrahepatic portosystemic shunt (TIPS has been recommended in these patients as a bridge to OLT. This is a new modality that has not been compared with previously established therapies such as the distal splenorenal shunt (DSRS. In this study we report our experience with 35 liver transplant recipients who had a previous TIPS (18 patients or DSRS (17 patients for variceal bleeding. The TIPS group had a significantly larger proportion of critically ill and Child-Pugh C patients. Mean operating time was more prolonged in the DSRS group (P=0.014 but transfusion requirements were similar. Intraoperative portal vein blood flow measurements averaged 2132±725 ml/min in the TIPS group compared with 1120±351ml/min in the DSRS group (P<0.001. Arterial flows were similar. Mean ICU and hospital stays were similar. There were 3 hospital mortalities in the DSRS group and none in the TIPS group (P=0.1. We conclude that TIPS is a valuable tool in the management of recurrent variceal bleeding prior to liver transplantation. Intra0Perative hemodynamic measurements suggest a theoretical advantage with TIPS. In a group of patients with advanced liver disease we report an outcome that is similar to patients treated with DSRS prior to liver transplantation. The role of TIPS in the treatment of nontransplant candidates remains to be clarified.

  11. Resonance features of coupled Josephson junctions: radiation and shunting

    Shukrinov, Yu M.; Seidel, P.; Il'ichev, E.; Nawrocki, W.; Grajcar, M.; Plecenik, P. A.; Rahmonov, I. R.; Kulikov, K.


    We study the phase dynamics and the resonance features of coupled Josephson junctions in layered superconductors and their manifestations in the current- voltage characteristics and temporal dependence of the electric charge in the superconducting layers. Results on the effect of the external radiation and shunting of the stack of Josephson junctions by LC-elements are presented. We discuss the ideas concerning the experimental observation of these resonances.

  12. Surgical treatment of hepatocellular carcinoma with severe intratumoral arterioportal shunt

    Hiromichi; Ishii; Teruhisa; Sonoyama; Shingo; Nakashima; Hiroyuki; Nagata; Atsushi; Shiozaki; Yoshiaki; Kuriu; Hisashi; Ikoma; Masayoshi; Nakanishi; Daisuke; Ichikawa; Hitoshi; Fujiwara; Kazuma; Okamoto; Toshiya; Ochiai; Yukihito; Kokuba; Chohei; Sakakura; Eigo; Otsuji


    We report a case of hepatocellular carcinoma (HCC) that caused a severe arterioportal shunt (APS). A 49-year-old man was admitted to hospital due to esophagogastric variceal hemorrhage and HCC, and underwent endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy (EIS). He was then referred to our hospital. Abdominal computed tomography revealed a lowdensity lesion in the posterior segment of the liver and an intratumoral APS, which caused portal hypertension. Although the patient underwen...

  13. Badness, madness and the brain - the late 19th-century controversy on immoral persons and their malfunctioning brains

    Schirmann, Felix


    In the second half of the 19th-century, a group of psychiatric experts discussed the relation between brain malfunction and moral misconduct. In the ensuing debates, scientific discourses on immorality merged with those on insanity and the brain. This yielded a specific definition of what it means t

  14. Using Noninvasive Brain Measurement to Explore the Psychological Effects of Computer Malfunctions on Users during Human-Computer Interactions

    Leanne M. Hirshfield


    Full Text Available In today’s technologically driven world, there is a need to better understand the ways that common computer malfunctions affect computer users. These malfunctions may have measurable influences on computer user’s cognitive, emotional, and behavioral responses. An experiment was conducted where participants conducted a series of web search tasks while wearing functional near-infrared spectroscopy (fNIRS and galvanic skin response sensors. Two computer malfunctions were introduced during the sessions which had the potential to influence correlates of user trust and suspicion. Surveys were given after each session to measure user’s perceived emotional state, cognitive load, and perceived trust. Results suggest that fNIRS can be used to measure the different cognitive and emotional responses associated with computer malfunctions. These cognitive and emotional changes were correlated with users’ self-report levels of suspicion and trust, and they in turn suggest future work that further explores the capability of fNIRS for the measurement of user experience during human-computer interactions.

  15. Minimally invasive ventriculo-atrial shunt for hydrocephalus

    李江山; 江勇豪; 程成; 张世凯


    Objective: To study the therapeutic effect of mini-traumatic ventriculo-atrial shunt on hydrocephalus. Methods: Seventeen patients were treated with right internal jugular venepuncture intubation to finish minimally invasive ventriculo-atrial shunt for hydrocephalus. The patients were evaluated by CT/MRI. The catheters were deployed at the proper position in the right atrium under X-ray fluoroscopy.Results: The hydrocephalus in all the 17 patients eliminated with this surgical procedure with a 100% success rate technically. The operational duration ranged from 0.75 to 1.5 h (average: 1 h). Mistaken puncture into the internal carotid artery as a complication occurred on 1 case.Conclusions: The mini-traumatic ventriculo-atrial shunt, as a novel minimal invasion technique, has the advantages of small trauma, no influence on local blood circulation, short time and simplicity at operation, rapid healing, and good short-term effect. Moreover, it is suitable for those patients with organic dysfunction.

  16. A case of repeated intracerebral hemorrhages secondary to ventriculoperitoneal shunt

    Jinbing Zhao


    Full Text Available Ventriculoperitoneal shunt is a routinely performed treatment in neurosurgical department. Intracerebral hemorrhage, as a complication after shunt catheterization, is really rare but with high mortality. In this study, we reported a case of a 74-year-old man who suffered from repeated intracerebral hemorrhage after ventriculoperitoneal shunt. The first hemorrhage happened 63 h after the 1st surgery, and most hematomas were located in the ipsilateral occipital lobe and intraventricles, along the ventricular catheter. Fresh blood clot casts blocked the external ventricular draining catheter, which was inserted into the right front horn during the 3rd surgery, indicating new intraventricular bleeding happened. A large hematoma in ipsilateral frontal lobe was detected on the 3rd day after the removal of external ventricular draining catheter. Different hemorrhagic locations and time points were encountered on the same case. We discussed the possible causes of repeated hemorrhage for this case, and the pre-operative preparation including risk evaluation in future clinical work.

  17. Executive Function Improvement in Normal Pressure Hydrocephalus Following Shunt Surgery

    Ezequiel Gleichgerrcht


    Full Text Available The aim of this investigation was to evaluate improvement of executive functions after shunt surgery in patients with early normal pressure hydrocephalus (NPH. Patients with NPH were assessed before and after shunt surgery with tests shown to be sensitive to damage to the prefrontal cortex (PFC. Significant differences were found between basal and follow-up performances on the Boston Naming Test, the backwards digits span, Part B of the Trail Making Test, and the number of words produced on the phonological fluency task. In conclusion, our study reveals that patients with NPH who respond positively to continuous slow lumbar cerebral spinal fluid drainage and receive a ventriculoperitoneal shunt implant, improve their performance on tasks of executive function. Due to the high demand for this form of mental processing in real-life complex scenarios, and based on the severe executive deficits present in both demented and non-demented NPH patients, we encourage the assessment of executive functions in this clinical group.

  18. Sodium Accumulation at Potential-Induced Degradation Shunted Areas in Polycrystalline Silicon Modules

    Harvey, Steven P.; Aguiar, Jeffery A.; Hacke, Peter; Guthrey, Harvey; Johnston, Steve; Al-Jassim, Mowafak


    We investigated potential-induced degradation (PID) in silicon mini-modules that were subjected to accelerated stressing to induce PID conditions. Shunted areas on the cells were identified with photoluminescence and dark lock-in thermography (DLIT) imaging. The identical shunted areas were then analyzed via time-of-flight secondary-ion mass spectrometry (TOFSIMS) imaging, 3-D tomography, and high-resolution transmission electron microscopy. The TOF-SIMS imaging indicates a high concentration of sodium in the shunted areas, and 3-D tomography reveals that the sodium extends more than 2 um from the surface below shunted regions. Transmission electron microscopy investigation reveals that a stacking fault is present at an area identified as shunted by DLIT imaging. After the removal of surface sodium, tomography reveals persistent sodium present around the junction depth of 300 nm and a drastic difference in sodium content at the junction when comparing shunted and nonshunted regions.


    Aditya Pratap


    Full Text Available Bowel perforation is an unusual complication of ventriculo peritoneal shunt. We are presenting a case of 15 month old male child with the shunt tubing protruding through the anus associated with bowel perforation. This complication occurred after the 13 months of insertion of ventriculo peritoneal shunt for congenital hydrocephalus. There were no signs of meningitis but mild signs of peritonitis were present. At laparotomy the tube was seen to enter the sigmoid colon and was encapsulated by the greater omentum. The tube was cut and the distal end removed via the anus. Proximal part of shunt also removed because there was contralateral shunt present. Perforation was repaired. We are here in presenting a rare complication of VP shunt.

  20. Chemoembolic Hepatopulmonary Shunt Reduction to Allow Safe Yttrium-90 Radioembolization Lobectomy of Hepatocellular Carcinoma

    Gaba, Ron C., E-mail: [University of Illinois Medical Center at Chicago, Department of Radiology, Section in Interventional Radiology (United States); VanMiddlesworth, Kyle A. [Midwestern University School of Medicine (United States)


    Yttrium-90 ({sup 90}Y) radioembolization represents an emerging transcatheter treatment option for the management of hepatocellular carcinoma (HCC). Elevation of the hepatopulmonary shunt fraction risks nontarget radiation to the lungs and may limit the use of {sup 90}Y therapy in patients with locally advanced disease with vascular invasion, who often demonstrate increased shunting. We present two cases in which patients with HCC and portal vein invasion resulting in elevated hepatopulmonary shunt fractions underwent chemoembolic shunt closure to allow safe {sup 90}Y radioembolization. Both patients demonstrated excellent tumor response and patient survival. On this basis, we propose a role for chemoembolic reduction of the lung shunt fraction before {sup 90}Y radioembolization in patients with extensive tumor-related hepatopulmonary shunting.

  1. Valved or valveless ventriculoperitoneal shunting in the treatment of post-haemorrhagic hydrocephalus

    Andreasen, Trine Hjorslev; Holst, Anders Vedel; Jørgensen, Alexander Lilja


    BACKGROUND: Implant infection and obstruction are major complications for ventriculoperitoneal shunts in patients with post-haemorrhagic hydrocephalus. In an effort to (1) reduce the incidence of these complications, (2) reduce the rate of shunt failure and (3) shorten the duration of neurosurgical...... hospitalisation, we have implemented valveless ventriculoperitoneal shunts at our department for adult patients with post-haemorrhagic hydrocephalus and haemorrhagic cerebrospinal fluid at the time of shunt insertion. METHODS: All adult patients (>18 years old) treated for post-haemorrhagic hydrocephalus.......3 %, p = 0.02), but a higher rate of overdrainage (10.3 % vs 2.6 %, p = 0.04). CONCLUSION: The use of a valveless shunting for patients with post-haemorrhagic hydrocephalus results in shorter duration of neurosurgical hospitalisation and lower rate of shunt infection, although these advantages should...

  2. A new shunt DC active filter of power supply in a steady high magnetic field facility

    WANG Lei; LIU Xiao-Ning; WANG Can


    A DC active power filter is an indispensable part in a high power and high stability power supply system, especially in the power supply system of the Steady High Magnetic Field Facility, which requires that the current ripple should be limited to 50 parts per million. In view of the disadvantages of the series DC active power filter and shunt Pulse Width Modulation DC active filter, this paper puts forward a novel DC active filter by combining the advantages of the transistor regulator and the shunt type. The structure and principle of the new shunt linear active filter are introduced. Meanwhile, the design of several key components that construct the new shunt linear active filter is also analyzed. The simulation model and an experimental prototype of the shunt linear active filter are developed, and the results verify that the parameter design is reasonable and the shunt active filter has a good filter effect.

  3. Laparoscopic assisted ventriculoperitoneal shunt revisions as an option for pediatric patients with previous intraabdominal complications

    Fernanda O. de Carvalho


    Full Text Available Multiple shunt failure is a challenge in pediatric neurosurgery practice and one of the most feared complications of hydrocephalus. Objective: To demonstrate that laparoscopic procedures for distal ventriculoperitoneal shunt failure may be an effective option for patients who underwent multiple revisions due to repetitive manipulation of the peritoneal cavity, abdominal pseudocyst, peritonitis or other situations leading to a “non reliable” peritoneum. Method: From March 2012 to February 2013, the authors reviewed retrospectively the charts of six patients born and followed up at our institution, which presented with previous intra-peritoneal complications and underwent ventriculoperitoneal shunt revision assisted by video laparoscopy. Results: After a mean follow-up period of nine months, all patients are well and no further shunt failure was identified so far. Conclusion: Laparoscopy assisted shunt revision in children may be, in selected cases, an effective option for patients with multiple peritoneal complications due to ventriculo-peritoneal shunting.

  4. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    Le R


    Full Text Available Ryan Le,1 Neeru Gupta1–3 1Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada; 2Ophthalmology and Vision Sciences, Glaucoma Unit, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada; 3Laboratory Medicine and Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, ON, CanadaAbstract: The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension glaucoma with good central vision, after having a previously failed trabeculectomy and tube shunt surgeries. The patient was receiving maximum medical glaucoma therapy of four different types with intraocular pressure of 17 mm Hg prior to gold shunt surgery. Five years later, intraocular pressure is well controlled in the low teens without the need for ocular medications, and glaucoma is stable following gold shunt surgery.Keywords: gold shunt, refractory glaucoma, glaucoma surgery, trabeculectomy, suprachoroidal space, tube shunt

  5. A multi-stack simulation of shunt currents in vanadium redox flow batteries

    Wandschneider, F. T.; Röhm, S.; Fischer, P.; Pinkwart, K.; Tübke, J.; Nirschl, H.


    A model for the shunt currents in an all-vanadium redox flow battery consisting of 3 stacks which are electrically connected in series. It is based on an equivalent circuit which treats the shunt current pathways as Ohmic resistors. The conductivity of the vanadium electrolyte has been measured for different state-of-charges in order to implement a dependency of the resistances on the state-of-charge of the system. Published results are used to validate the simulation data of a single stack. Three setups of pipe networks are evaluated using the model. The pipe connections between the stacks give rise to external shunt currents, which also increase the amount of shunt currents within the stacks. These connections also lead to a nonuniform distribution of the shunt currents. The effects of the shunt currents on the Coulombic efficiency and the energy efficiency of the system are studied by the means of the model.

  6. Transjugular intrahepatic portosystemic shunt combined with esophagogastric variceal embolization in the treatment of a large gastrorenal shunt

    Qin; Jiang; Ming-Quan; Wang; Guo-Bing; Zhang; Qiong; Wu; Jian-Ming; Xu; De-Run; Kong


    AIM: To evaluate the efficacy and safety of transjugular intrahepatic portosystemic shunt(TIPS) combined with stomach and esophageal variceal embolization(SEVE) in cirrhotic patients with a large gastrorenal vessel shunt(GRVS).METHODS: Eighty-one cirrhotic patients with gastric variceal bleeding(GVB) associated with a GRVS were enrolled in the study and accepted TIPS combined with SEVE(TIPS + SEVE), by which portosystemic pressuregradient(PPG), biochemical, TIPS-related complications, shunt dysfunction, rebleeding, and death were evaluated. RESULTS: The PPGs before TIPS were greater than 12 mmH g in 81 patients. TIPS + SEVE treatment caused a significant decrease in PPG(from 37.97 ± 6.36 mmH g to 28.15 ± 6.52 mm Hg, t = 19.22, P < 0.001). The percentage of reduction in PPG was greater than 20%from baseline. There were no significant differences in albumin, alanine aminotransferase, aspartate aminotransferase, bilirubin, prothrombin time, or Child-Pugh score before and after operation. In all patients, rebleeding rates were 3%, 6%, 12%, 18%, and 18% at 1,3, 6, 12, and 18 mo, respectively. Five patients(6.2%)were diagnosed as having hepatic encephalopathy. The rates of shunt dysfunction were 0%, 4%, 9%, 26%,and 26%, at 1, 3, 6, 12, and 18 mo, respectively. The cumulative survival rates in 1, 3, 6, 12, and 18 mo were100%, 100%, 95%, 90%, and 90%, respectively.CONCLUSION: Our preliminary results indicated that the efficacy and safety of TIPS + SEVE were satisfactory in cirrhotic patients with GVB associated with a GRVS(GVB + GRVS).

  7. Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe)-Gallium (Ga) Alloy


    Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe)-Gallium (Ga) Alloy by Andrew James Murray and Dr. JinHyeong Yoo...Aberdeen Proving Ground, MD 21005 ARL-TN-0566 September 2013 Evaluation of Magnetostrictive Shunt Damper Performance Using Iron (Fe... Magnetostrictive Shunt Damper Performance Using Iron (Fe)- Gallium (Ga) Alloy 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  8. Partial portacaval shunt with H-grafts to treat portal hypertension

    XU Geliang; HU Hejie; LI Jiansheng; YANG Shugao; CHAI Zhongpei; XU Rongnan


    Partial portosystemic shunts have been popularized because of a reported low rate of mortality and morbidity (especially encephalopathy,liver failure and occlusion).The results of partial portacaval shunts[small-diameter expanded polytetrafluoroethylene(ePTFE)H-graft portacaval shunt]were retrospectively reviewed to evaluate the clinical efficacy in the treatment of portal hypertension.Forty-three patients with portal hypertension were treated by small-diameter H-graft of ePTFE portacaval shunt from May 1995 to April 2006.Thirty-three had externally ringed grafts and ten had non-ringed ones.Ten had grafts of 10mm in diameter and 33 had grafts of 8 mm.The left gastric artery and coronary vein were ligated in all the cases.Six had pericardial devascularization and splenectomy was performed in 42.An average decrease of flee portal pressure(FPP)from(33.24±4.78)cm H2O before shunting and(13.65±5.65)cmH2O after shunting was observed.The portal blood flow was reduced by one-third of that before shunt.Thirty-eight patients survived and no upper gastro-intestinal rebleeding occurred in the follow-up period(50.5 months in average).Two were out of contact.Color Doppler ultrasonography and/or portography revealed the shunts were Patent in 38 cases and were occluded in three cases(3/41,7.3%).Encephalopathy developed in five cases(5/41,12.2%).Partial(small-diameter ePTFE H-graft)portacaval shunting Can reduce the portal pressure effectively.Majority of the hepatic flow from the portal vein can be maintained adequately.The shunts with reinforced grafts can keep a higher rate of patency.The morbidity of encephalopathy was lower than those with total shunt.The partial portacaval shunt is effective in preventing recurrent variceal bleeding.

  9. Small-diameter prosthetic H-graft portacaval shunts in the treatment of portal hypertension

    胡何节; 许戈良; 李建生; 杨树高; 柴仲培; 徐荣楠


    Background Portasystemic shunts, especially total shunts, are effective tools for reducing portal pressure and controlling variceal bleeding but lead to high risk of encephalopathy and accelerating liver ailure. The purpose of this study is to evaluate the clinical effects of small-diameter expanded polytetrafluoroethylene (ePTFE) H-graft portacaval shunts in the treatment of portal hypertension. Methods Thirty-one patients with portal hypertension were treated with ePTFE small-diameter H-graft portacaval shunts from December 1995 to April 2002. Twenty-one had externally ringed grafts and 10 had non-ringed grafts; 20 had 10 mm diameter grafts and 11 had 8 mm grafts. The left gastric artery and coronary vein were ligated in 22 patients. Additionally, 6 patients underwent pericardial devascularization, and splenectomies were performed on 30 patients. Results An average decrease of free portal pressure (FPP) from (32.13 ~4.86) cmH2O before shunting to (12.55±5. 57) cmH2O after shunting was observed. Portal blood flow was reduced by 1/3 compared with the levels measured before shunting. Twenty-eight patients survived after the operation, and no upper gastrointestinal rebleeding occurred in the follow-up period (40.2 months on average). We lost contact with one patient. Color Doppler ultrasonography and/or portography revealed the shunts to be patent in 28 cases and occluded in 2 (6.4% ) cases. Encephalopathy developed in 4 patients (12.9%). Conclusion Small-diameter ePTFE H-graft portacaval shunts can effectively reduce portal pressure. Moreover, the majority of the hepatopetal flow from the portal vein can be adequately maintained. The reinforced shunts may achieve a higher rate of patency. Morbidity from encephalopathy was less frequent than in pateints receiving total shunts. Small-diameter H-graft portacaval shunts are also effective in preventing recurrent variceal bleeding.

  10. Focal Sparing of the Fatty Liver Caused by a Nontumorous Arterioportal Shunt

    Lee, Min Woo; Kim, Young Jun; Jeon, Hae Jeong; Lee, Nam Ju; Moon, Sung Gyu; Yi, Jeong Geun [Konkuk University Hospital, Seoul (Korea, Republic of)


    We present two cases of focal fatty sparing caused by a nontumorous arterioportal shunt. Two patients underwent ultrasonography (US) as a part of routine medical screening, which revealed a hypoechoic lesion in the diffuse fatty liver. Each lesion appeared to be an arterioportal shunt on triphasic mutidetector computed tomography (CT) and was seen as being slightly hyperdense on noncontrast CT. No tumors were delineated around or within the arterioportal shunt. Both lesions remained unchanged on six-month follow-up US

  11. Ultrasonic Contrast Portography for Demonstration of Intrahepatic Porto-systemic Shunts

    Yi-Hong Chou


    Full Text Available Spontaneous intrahepatic porto-systemic shunts (IHPSS can be disclosed with ultrasound (US and color Doppler ultrasound (CDU. However, direct evidence of the shunt on US or CDU may not be convincing. In this report we demonstrate the presence of IHPSS by ultrasonic contrast portography with intravenous injection of microbubble-based contrast agent (MBCA. With this technique, the MBCA was depicted to enter the hepatic vein through the shunt, and then flowed into the inferior vena cava.

  12. High-accuracy current measurement with low-cost shunts by means of dynamic error correction

    Weßkamp, Patrick; Melbert, Joachim


    Measurement of electrical current is often performed by using shunt resistors. Thermal effects due to self-heating and ambient temperature variation limit the achievable accuracy, especially if low-cost shunt resistors with increased temperature coefficients are utilized. In this work, a compensation method is presented which takes static and dynamic temperature drift effects into account and provides a significant reduction of measurement error. A thermal model of the shunt...

  13. Case report: massive lower intestinal bleeding from ileal varices. Treatment with transjugular intrahepatic portosystemic shunt (TIPSS); Fallbericht: Massive untere gastrointestinale Blutung aus ilealen Varizen. Behandlung mittels transjugulaerem intrahepatischem portosystemischem Shunt (TIPSS)

    Lopez-Benitez, R. [Universitaetsklinikum Heidelberg (Germany). Abteilung fuer Diagnostische und Iinterventionelle Radiologie; Universitaetsklinikum, Abteilung fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany); Seidensticker, P.; Richter, G.M.; Stampfl, U.; Hallscheidt, P. [Universitaetsklinikum Heidelberg (Germany). Abteilung fuer Diagnostische und Iinterventionelle Radiologie


    Acute gastrointestinal bleeding in patients with liver cirrhosis is associated with a high mortality. Ileal varices and collaterals from ectopic vessels are extremely rare, encountered in less than 5% of the cirrhotic patients. The diagnosis is frequently delayed because the regular diagnostic methods such as gastroscopy or colonoscopy are unsuccessful in accurate the source of bleeding in the majority of the cases. We report an unusual case of massive and uncontrollable lower intestinal bleeding from ileal varices with right ovarian vein anastomosis in a 56 year-old female patient with liver cirrhosis and previous history of abdominal and pelvic surgery. The accurate angiographic and computed tomography diagnosis allowed fast decompression of the portal venous system using a transjugular intrahepatic portosystemic shunt. (orig.) [German] Akute gastrointestinale Blutungen sind bei Leberzirrhosepatienten mit einer hohen Mortalitaet verbunden. Ileale Varizen und Kollateralen aus anderen ektopen Gefaessen des Darms sind extrem selten und treten bei weniger als 5% aller Zirrhosepatienten auf. Die Diagnosestellung erfolgt oft verspaetet, da die ueblichen diagnostischen Untersuchungsmethoden wie Gastroskopie oder Koloskopie in den meisten Faellen die Blutungsquelle nicht ausreichend darstellen. Wir berichten ueber einen ungewoehnlichen Fall von massiver und unkontrollierbarer unterer gastroinstestinaler (GI-)Blutung aus ilealen Varizen mit Verbindung zur rechten V. ovarica einer 56-jaehrigen Frau, bei der anamnestisch eine Leberzirrhose und abdominelle Operationen sowie Operationen im Bereich des Beckens bekannt waren. Die genaue angiographische und computertomographische Diagnose erlaubte eine rasche Dekompression des Portalvenensystems mittels eines transjugulaeren portosystemischen Shunts. (orig.)

  14. Robert H. Pudenz (1911-1998) and Ventriculoatrial Shunt: Historical Perspective.

    Konar, Subhas K; Maiti, Tanmoy K; Bir, Shyamal C; Kalakoti, Piyush; Nanda, Anil


    Robert H. Pudenz was a renowned neurosurgeon in North America in the 20th century, famous for his contributions in the evolution of the shunt valve and ventriculoatrial shunt surgery. With his innovative idea and help from Heyer, in 1955, he demonstrated that a venous catheter worked best when in the right atrium and that the slit valve should be located at the most distal portion of the shunt system to prevent retrograde filling and thrombosis. He also contributed to various experimental studies on the brain, especially the electrical response of different neural structures. This historical vignette focuses on the work of Robert Pudenz and the evolution of the ventriculoatrial shunt.

  15. Intrahepatic porto-hepatic venous shunts in Rendu-Osler-Weber disease: imaging demonstration

    Matsumoto, Shunro; Mori, Hiromu; Yamada, Yasunari; Hayashida, Tomoko; Hori, Yuzo; Kiyosue, Hiro [Department of Radiology, Oita Medical University, Idaigaoka 1-1, Hasama-machi, 879-5593, Oita (Japan)


    This study describes the imaging features of the intrahepatic portohepatic venous (PHV) shunt, which is a potential cause of portosystemic encephalopathy in Rendu-Osler-Weber disease. Six patients with Rendu-Osler-Weber disease (two men, four women; age range 42-73 years) were retrospectively studied. There were two from one family and three from another family. Of these patients, one was diagnosed with definitive portosystemic encephalopathy because of a psychiatric disorder. We retrospectively reviewed the radiological examinations, including abdominal angiography (n=6), three-phase dynamic helical computed tomography (CT; n=3), and conventional enhanced CT (n=1). In one patient, CT during angiography and CT angioportography were also performed. Evaluation was placed on the imaging features of intrahepatic PHV shunts. On angiography, intrahepatic PHV shunts showing multiple and small shunts <5 mm in diameter in an apparent network were detected in all patents. In two patients, a large shunt with a size of either 7 or 10 mm was associated. These intrahepatic PHV shunts were predominantly distributed in the peripheral parenchyma. Intrahepatic PHV shunts would be characterized by small and multiple shunts in an apparent network on the periphery with or without a large shunt. (orig.)

  16. Validated linear dynamic model of electrically-shunted magnetostrictive transducers with application to structural vibration control

    Scheidler, Justin J.; Asnani, Vivake M.


    This paper presents a linear model of the fully-coupled electromechanical behavior of a generally-shunted magnetostrictive transducer. The impedance and admittance representations of the model are reported. The model is used to derive the effect of the shunt’s electrical impedance on the storage modulus and loss factor of the transducer without neglecting the inherent resistance of the transducer’s coil. The expressions are normalized and then shown to also represent generally-shunted piezoelectric materials that have a finite leakage resistance. The generalized expressions are simplified for three shunts: resistive, series resistive-capacitive, and inductive, which are considered for shunt damping, resonant shunt damping, and stiffness tuning, respectively. For each shunt, the storage modulus and loss factor are plotted for a wide range of the normalized parameters. Then, important trends and their impact on different applications are discussed. An experimental validation of the transducer model is presented for the case of resistive and resonant shunts. The model closely predicts the measured response for a variety of operating conditions. This paper also introduces a model for the dynamic compliance of a vibrating structure that is coupled to a magnetostrictive transducer for shunt damping and resonant shunt damping applications. This compliance is normalized and then shown to be analogous to that of a structure that is coupled to a piezoelectric material. The derived analogies allow for the observations and equations in the existing literature on structural vibration control using shunted piezoelectric materials to be directly applied to the case of shunted magnetostrictive transducers.

  17. Persistent hydrocephalus due to postural activation of a ventricular shunt anti-gravity device.

    Craven, Claudia L; Toma, Ahmed K; Watkins, Laurence D


    The ever present need to balance over drainage with under drainage in hydrocephalus has required innovations including adjustable valves with antigravity devices. These are activated in the vertical position to prevent siphoning. We describe a group of bedridden patients who presented with unexplained under drainage caused by activation of antigravity shunt components produced by peculiar head/body position. Retrospective single centre case series of hydrocephalus patients, treated with ventriculo-peritoneal (VP) shunt insertion between April 2014 - February 2016. These patients presented with clinical and radiological under drainage syndrome. Medical notes were reviewed for clinical picture and outcome. Radiological studies were reviewed assessing shunt placement and ventricular size. Seven patients presented with clinical and radiological under drainage syndrome. A consistent posturing of long term hyper-flexion of the neck whilst lying supine was observed. All patients had similar shunt construct (adjustable Miethke ProGAV valve and shunt assistant anti-gravity component). In each of those patients a hypothesis was formulated that neck flexion was activating the shunt assistance anti-gravity component in supine position. Five patients underwent shunt revision surgery removing the shunt assistant device from the cranium and adding an anti-gravity component to the shunt system at the chest. One had the shunt assistant completely removed and one patient was managed conservatively with mobilisation. All patients had clinical and radiological improvement. Antigravity shunt components implanted cranially in bedridden hydrocephalus patients will produce underdrainage due to head flexion induced anti-gravity device activation. In these patients, anti-gravity devices should be placed at the chest. Alternatively, special nursing attention should be paid to head-trunk angle.

  18. Influence of malfunctions of the maintenance activities on the urban buses fuel consumption

    George, Crişan; Nicolae, Filip


    Optimization of activities with the aim to provide quality service in conditions of high profitability, is one of the main objectives chased by managers in transportation companies. As a consequence, directing the attention towards monitoring of maintenance activities of vehicles fleet, can achieve desired results. Two of the most important issues related to the maintenance activity, is the increase of reliability and reduction of fuel consumption of the vehicles fleet. Aforementioned actions represents a way forward for raising the quality and profitability of services offered. In this paper, the main ways of monitoring the fuel consumption, in order to reduce it and increase the reliability of transportation vehicles fleet, are presented. For the evaluation of the maintenance system and the degree of influence of malfunctions recorded on the fuel consumption, using the Pareto -ABC method, following case study on a fleet of buses for urban public transport has been conducted. Results obtained highlights the deficiencies of the maintenance process carried out and constitutes a solid base for the reorganization of the maintenance activity, involving preventive maintenance activities, in order to contribute decisively to the results targeted by the management of transport companies.

  19. Time-resolved in situ measurement of mitochondrial malfunction by energy transfer spectroscopy

    Schneckenburger, Herbert; Sailer, Reinhard; Strauss, Wolfgang S.; Lyttek, Marco; Stock, Karl; Zipfl, Peter


    To establish optical in situ detection of mitochondrial malfunction, nonradiative energy transfer from the coenzyme NADH to the mitochondrial marker rhodamine 123 (R123) was examined. Dual excitation of R123 via energy transfer from excited NADH molecules as well as by direct absorption of light results in two fluorescence signals whose ratio is a measure of mitochondrial NADH. A screening system was developed in which these signals are detected simultaneously using a time-gated (nanosecond) technique for energy transfer measurements and a frequency selective technique for direct excitation and fluorescence monitoring of R123. Optical and electronic components of the apparatus are described, and results obtained from cultivated endothelial cells are reported. The ratio of fluorescence intensities excited in the near ultraviolet and blue-green spectral ranges increased by a factor 1.5 or 1.35 after inhibition of the mitochondrial respiratory chain by rotenone at cytotoxic or noncytotoxic concentrations, respectively. Concomitantly the amount of mitochondrial NADH increased. Excellent linearity between the number of cells incubated with R123 and fluorescence intensity was found in suspension.

  20. Microscopic energy transfer spectroscopy to determine mitochondrial malfunction in human myotubes

    Gschwend, Michael H.; Strauss, Wolfgang S. L.; Brinkmeier, H.; Ruedel, R.; Steiner, Rudolf W.; Schneckenburger, Herbert


    A microscopic equipment is reported for examination of cellular autofluorescence and determination of energy transfer in vitro, which is proposed to be an appropriate tool to investigate mitochondrial malfunction. The method includes fluorescence microscopy combined with time-gated (nanosecond) fluorescence emission spectroscopy and is presently used to study mitochondrial metabolism of human myotube primary cultures Enzyme complexes of the respiratory chain, located at the inner mitochondrial membrane, were inhibited by various drugs, and fluorescence of the mitochondrial coenzyme nicotinamide adenine dinucleotide (NADH) as well as of the mitochondrial marker rhodamine 123 (R123) was examined. After inhibition of enzyme complex I (NADH-coenzyme Q reductase) by rotenone or enzyme complex III (coenzyme QH2-cytochrome c reductase) by antimycin a similar or increased NADH fluorescence was observed. In addition, energy transfer from excited states of NADH (energy donor) to R123 (energy acceptor) was deduced from a decrease of NADH fluorescence after coincubation with these inhibitors and R123. Application of microscopic energy transfer spectroscopy for diagnosis of congenital mitochondrial deficiencies is currently in preparation.

  1. Rhomboid-7 over-expression results in Opa1-like processing and malfunctioning mitochondria.

    Rahman, Mokhlasur; Kylsten, Per


    Rhomboid-7 (rho-7) is a mitochondrial-specific intramembranous protease. The loss-of-function mutation rho-7 results in semi-lethality, while escapers have a reduced lifespan with several neurological disorders [1]. Here we show that general, or CNS-specific expression of rho-7 can rescue the lethality of rho-7. General, or CNS-specific over-expression of rho-7 in otherwise wild-type animals caused semi-lethality, with approximately 50% of the animals escaping this lethality, developing into adults displaying a shortened life span with larval locomotory problem. On a cellular level, over-expression resulted in severe depression of ATP levels and cytochrome c oxidase subunit II mRNA levels, a lowered number of mitochondria in neurons and aggregation of mitochondria in the brain indicating mitochondrial malfunction. Over-expression of rho-7 in developing eye discs resulted in an elevated apoptotic index. In the CNS, elevated levels of rho-7 were accompanied by both isoforms of Opa1-like, a dynamin-like GTPase, a mitochondrial component involved in regulating mitochondrial dynamics and function, including apoptosis. Most, but not all, of rho-7 over-expression phenotypes were suppressed by introducing a heterozygous mutation for Opa1-like. Our results suggest that rho-7 and Opa1-like function in a common molecular pathway affecting mitochondrial function and apoptosis in Drosophila melanogaster.

  2. Oxidative stress, mitochondrial and proteostasis malfunction in adrenoleukodystrophy: A paradigm for axonal degeneration.

    Fourcade, Stéphane; Ferrer, Isidre; Pujol, Aurora


    Peroxisomal and mitochondrial malfunction, which are highly intertwined through redox regulation, in combination with defective proteostasis, are hallmarks of the most prevalent multifactorial neurodegenerative diseases-including Alzheimer's (AD) and Parkinson's disease (PD)-and of the aging process, and are also found in inherited conditions. Here we review the interplay between oxidative stress and axonal degeneration, taking as groundwork recent findings on pathomechanisms of the peroxisomal neurometabolic disease adrenoleukodystrophy (X-ALD). We explore the impact of chronic redox imbalance caused by the excess of very long-chain fatty acids (VLCFA) on mitochondrial respiration and biogenesis, and discuss how this impairs protein quality control mechanisms essential for neural cell survival, such as the proteasome and autophagy systems. As consequence, prime molecular targets in the pathogenetic cascade emerge, such as the SIRT1/PGC-1α axis of mitochondrial biogenesis, and the inhibitor of autophagy mTOR. Thus, we propose that mitochondria-targeted antioxidants; mitochondrial biogenesis boosters such as the antidiabetic pioglitazone and the SIRT1 ligand resveratrol; and the autophagy activator temsirolimus, a derivative of the mTOR inhibitor rapamycin, hold promise as disease-modifying therapies for X-ALD.

  3. Uncovering the link between malfunctions in Drosophila neuroblast asymmetric cell division and tumorigenesis

    Kelsom Corey


    Full Text Available Abstract Asymmetric cell division is a developmental process utilized by several organisms. On the most basic level, an asymmetric division produces two daughter cells, each possessing a different identity or fate. Drosophila melanogaster progenitor cells, referred to as neuroblasts, undergo asymmetric division to produce a daughter neuroblast and another cell known as a ganglion mother cell (GMC. There are several features of asymmetric division in Drosophila that make it a very complex process, and these aspects will be discussed at length. The cell fate determinants that play a role in specifying daughter cell fate, as well as the mechanisms behind setting up cortical polarity within neuroblasts, have proved to be essential to ensuring that neurogenesis occurs properly. The role that mitotic spindle orientation plays in coordinating asymmetric division, as well as how cell cycle regulators influence asymmetric division machinery, will also be addressed. Most significantly, malfunctions during asymmetric cell division have shown to be causally linked with neoplastic growth and tumor formation. Therefore, it is imperative that the developmental repercussions as a result of asymmetric cell division gone awry be understood.

  4. Machinery malfunction diagnosis and correction: Vibration analysis and troubleshooting for process industries

    Eisemann, R.C.


    This book is an up-to-date, hands-on single-source diagnostic guide for process machinery. It contains extensive illustrations, sample calculations, and explicit physical explanations; a 7-point problem solving methodology based on the authors` 40+ years of expertise; and 52 highly detailed field case histories describing problem definition, investigation, analytical and measurement techniques, and the final corrective solutions. It includes usable computations, analytical procedures, definitions, explanations of fundamental machinery behavior, rotordynamics, static and dynamic measurements, data acquisition and processing, data interpretation, plus field proven problem-solving techniques. The book begins with fundamental concepts of lateral and torsional mechanical motion, and expands these basic models into acceptable simulations of real machines. Steam, gas, and hydro turbines, gear boxes, centrifugal and reciprocating compressors, pumps, expanders, motors and generators are analyzed from multiple perspectives. This text describes common malfunctions, plus unusual excitations and failure mechanisms. It is extensively illustrated, and contains detailed examples with sample calculations--along with case histories that cover refineries, chemical plants, power plants, paper mills and other processing facilities.

  5. Early shunt complications in 46 children with hydrocephalus Complicações precoces de válvula de hidrocefalia em 46 crianças

    Moisés Heleno Vieira Braga


    Full Text Available OBJECTIVE: To determine the causes of early shunt complications in 46 children with hydrocephalus. METHOD: A retrospective study was conducted on 46 children submitted to ventriculoperitoneal shunt surgery between February 2005 and February 2007. RESULTS: Thirteen (28% patients presented complications, which were due to infection in 9 (69% and to malfunction of the shunt system in 4 (31%.The mean number of surgical procedures performed on patients who presented complications was 2.8 per patient, with a total of 46 surgeries in this group. All patients with infectious complications were identified during their hospital stay. CONCLUSIONS: Infection was the most common complication. The infection rate was proportional to the length of hospital stay. All patients with hydrocephalus due to tumors or myelomeningocele presented complications. A higher incidence of infections was observed in children older than 2 years.OBJETIVO: Determinar e as causas das complicações precoces nas válvulas de hidrocefalia de 46 crianças. MÉTODO: Um estudo retrospectivo foi realizado com 46 crianças submetidas a colocação de válvula de hidrocefalia no período de fevereiro de 2005 a fevereiro de 2007. RESULTADOS: Obtivemos 13 (28% pacientes com complicações sendo 9 (69% causadas por infecção e 4 (31% por mal funcionamento da válvula de hidrocefalia. A média de procedimentos cirúrgicos realizados nos pacientes com complicações foi de 2,8 por paciente, sendo o total de 46 cirurgias neste grupo. Todos os pacientes com complicações infecciosas foram detectados durante a internação hospitalar. CONCLUSÕES: Infecção foi a complicação mais comum. O índice de infecção foi proporcional ao tempo de permanência hospitalar. Todos os pacientes portadores de hidrocefalia secundária a tumores ou mielomeningocele complicaram. As crianças maiores de 2 anos de idade tiveram maior incidência de infecções.

  6. Characteristics of shunting arc discharge for carbon ion source

    Takaki, K.; Mukaigawa, S.; Fujiwara, T.; Kumagai, M.; Yukimura, K.


    The criteria of initial resistance of carbon rod for shunting arc ignition are described in this article. The five different resistances were used. The rods are 40 mm in length and 2 mm in diameter. The carbon rod was set in the vacuum and was initially heated up with a pulsed current supplied by a charged capacitor with a capacitance of 20 μF, followed by a self-ignition. The heating energy is almost independent of the charging voltage of the capacitor. The heating energy increases with decreasing the rod resistance, whereas the energy deposited in the plasma and the utilizing efficiency of the charged energy in the capacitor decreases.

  7. Shunting arc plasma source for pure carbon ion beama)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.


    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  8. Shunting arc plasma source for pure carbon ion beam.

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y


    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  9. Valproic acid-induced hyperammonaemic coma and unrecognised portosystemic shunt.

    Nzwalo, Hipólito; Carrapatoso, Leonor; Ferreira, Fátima; Basilio, Carlos


    Hyperammonaemic encephalopathy is a rare and potentially fatal complication of valproic acid treatment. The clinical presentation of hyperammonaemic encephalopathy is wide and includes seizures and coma. We present a case of hyperammonaemic coma precipitated by sodium valproate use for symptomatic epilepsy in a patient with unrecognised portosystemic shunt, secondary to earlier alcoholism. The absence of any stigmata of chronic liver disease and laboratory markers of liver dysfunction delayed the recognition of this alcohol-related complication. The portal vein bypass led to a refractory, valproic acid-induced hyperammonaemic coma. The patient fully recovered after dialysis treatment.

  10. Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study.

    Shannon, Chevis N; Carr, Kevin R; Tomycz, Luke; Wellons, John C; Tulipan, Noel


    Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

  11. Normal-pressure hydrocephalus: current understanding of diagnostic tests and shunting

    Black, P.M.


    Normal-pressure hydrocephalus is no longer difficult to diagnose or treat-cranial computed tomographic scanning has made the diagnosis of ventricular enlargement straightforward, and shunt placement often helps the patient whose condition can be traced to a specific cause. Predicting accurately whether a patient will benefit from a shunt, however, is still problematic.

  12. Ventriculoperitoneal shunt tube infection and changing pattern of antibiotic sensitivity in neurosurgery practice: Alarming trends

    Vikas Kumar


    Conclusion: Ventriculoperitoneal shunt infection has become an important concern in cases of hydrocephalus. Due to the development of a high proportion of antibiotic resistance, we recommend an empirical therapy of antibiotic therapy for prophylaxis and suspected infection in ventriculoperitoneal shunt surgery.

  13. Fractured inlet connecting tube of the flat bottom flushing device of a posterior fossa cystoperitoneal shunt

    Abbas Amirjamshidi


    Conclusion: Awareness of the possibility of fracture site in the junction of the inlet connector of flat bottom shunt systems is warranted and can be diagnosed by three-dimensional computed tomography (3D CT imaging without performing shunt series study.

  14. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics.

    Miyake, Hiroji


    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt.

  15. Medication overuse as a cause of chronic headache in shunted hydrocephalus patients

    Willer, Lasse; Jensen, R H; Juhler, M


    To highlight the group of hydrocephalus patients known to have a long history of shunt revisions and refractory chronic headache. When a shunt in perfect working order has no effect on headache, other causes of headache should be investigated. In this paper, patients with medication overuse...

  16. Minimally-invasive treatment of communicating hydrocephalus using a percutaneous lumboperitoneal shunt

    Lu JIA; Guo-ping LI; Zhong-xin ZHAO; Chao YOU; Jia-gang LIU; Si-qing HUANG; Min HE; Pei-gang JI; Jie DUAN; Yi-jun ZENG


    Objective: To investigate the clinical value of a minimally-invasive treatment of communicating hydrocephalus using a percutaneous lumboperitoneal (LP) shunt. Method: The clinical and long-term follow-up data of 256 patients suffering from communicating hydrocephalus and undergoing percutaneous LP shunt during 1998 to 2008 were retrospectively analyzed. Results: After the follow-up, which lasted 6 months to 10 years, 219 cases of communicating hydrocephalus recovered well (ventricular size returned to normal and symptoms completely disappeared),25 cases were brought under control (ventricle size reduced by 50% and symptoms partially abated), and 12 cases showed no obvious changes. Fifteen obese subjects needed modifications of the shunt due to the obstruction of the abdominal end following wrapping, and one subject underwent extubation as the subject was unable to tolerate stimulation of the cauda equina. The effectiveness of shunting was 91.40% and the probability of shunt-tube obstruction, which occurs predominantly in the abdominal end, was only 5.85%, far lower than that of ventriculoperitoneal (VP)shunt. Three subjects had a history of infection following VP shunting. Conclusion: LP shunting is minimally invasive and effective in treating communicating hydrocephalus, with fewer complications.

  17. Creation of transcatheter aortopulmonary and cavopulmonary shunts using magnetic catheters: feasibility study in swine.

    Levi, Daniel S; Danon, Saar; Gordon, Brent; Virdone, Nicky; Vinuela, Fernando; Shah, Sanjay; Carman, Greg; Moore, John W


    Surgical shunts are the basic form of palliation for many types of congenital heart disease. The Glenn shunt (superior cavopulmonary connection) and central shunt (aortopulmonary connection) represent surgical interventions that could potentially be accomplished by transcatheter techniques. We sought to investigate the efficacy of using neodymium iron boron (NdFeB) magnetic catheters to create transcatheter cavopulmonary and aortopulmonary shunts. NdFeB magnets were machined and integrated into catheters. "Target" catheters were placed in the pulmonary arteries (PAs), and radiofrequency "perforation" catheters were placed in either the descending aorta (DAo) for central shunts or the superior vena cava (SVC) for Glenn shunts. The magnet technique or "balloon target" method was used to pass wires from the DAo or the SVC into the PA. Aortopulmonary and cavopulmonary connections were then created using Atrium iCAST covered stents. Magnet catheters were used to perforate the left pulmonary artery from the DAo, thereby establishing a transcatheter central shunt. Given the orientation of the vasculature, magnetic catheters could not be used for SVC-to-PA connections; however, perforation from the SVC to the right pulmonary artery was accomplished with a trans-septal needle and balloon target. Transcatheter Glenn or central shunts were successfully created in four swine.

  18. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain


    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements.

  19. The use of contrast echocardiography for the detection of cardiac shunts

    O.I.I. Soliman (Osama Ibrahim Ibrahim); M.L. Geleijnse (Marcel); F.J. Meijboom (Folkert); A. Nemes (Attila); O. Kamp (Otto); P. Nihoyannopoulos (Petros); N. Masani (Navroz); S.B. Feinstein (Steven); F.J. ten Cate (Folkert)


    textabstractRecently, debate has erupted about the clinical significance of cardiovascular shunts. Several major health problems such as stroke and migraine have been associated with patent foramen ovale (PFO) with right-to-left shunt (RLS). The nature of the relationship between these syndromes and

  20. Measurement of the ductal L-R shunt during extracorporeal membrane oxygenation in the lamb.

    Tanke, R.B.; Heijst, A.F.J. van; Klaessens, J.H.G.M.; Daniels, O.; Festen, C.


    OBJECTIVE: In neonates, initially a ductal shunt is often observed during veno-arterial extracorporeal membrane oxygenation (ECMO). Depending on the degree of pulmonary hypertension in these patients, the ductal shunt will be right to left (R-L), left to right (L-R), or bidirectional. A ductal L-R s

  1. The influence of ductal left-to-right shunting during extracorporeal membrane oxygenation.

    Tanke, R.B.; Daniëls, O.; Heyst, A. van; Lier, H.J.J. van; Festen, C.


    BACKGROUND/PURPOSE: The aim of this study was to analyze whether a ductal left-to-right (L-R) shunt will prolong extracorporeal membrane oxygenation (ECMO) in neonates with severe pulmonary hypertension. This report discusses the onset and termination of a ductal L-R shunt and its potential influenc

  2. Congenital portosystemic shunts: Imaging findings and clinical presentations in 11 patients

    Konstas, Angelos A., E-mail: [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114 (United States); Digumarthy, Subba R.; Avery, Laura L. [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114 (United States); Wallace, Karen L. [Department of Radiology, Mount Auburn Hospital and Harvard Medical School, 330 Mount Auburn St, Cambridge, MA 02138 (United States); Lisovsky, Mikhail; Misdraji, Joseph [Department of Pathology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114 (United States); Hahn, Peter F. [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St, Boston, MA 02114 (United States)


    Objective: To evaluate the clinical anatomy and presentations of congenital portosystemic shunts, and determine features that promote recognition on imaging. Materials and methods: Institutional review board approval was obtained for this HIPAA-compliant study. The requirement for written informed consent was waived. Radiology reports were retrospectively reviewed from non-cirrhotic patients who underwent imaging studies from January 1999 through February 2009. Clinical sources reviewed included electronic medical records, archived images and histopathological material. Results: Eleven patients with congenital portosystemic shunts were identified (six male and five female; age range 20 days to 84 years). Seven patients had extrahepatic and four patients had intrahepatic shunts. All 11 patients had absent or hypoplastic intrahepatic portal veins, a feature detected by CT and MRI, but not by US. Seven patients presented with shunt complications and four with presentations unrelated to shunt pathophysiology. Three adult patients had four splenic artery aneurysms. Prospective radiological evaluation of five adult patients with cross-sectional imaging had failed prospectively to recognize the presence of congenital portosystemic shunts on one or more imaging examinations. Conclusions: Congenital portosystemic shunts are associated with splenic artery aneurysms, a previously unrecognized association. Portosystemic shunts were undetected during prospective radiologic evaluation in the majority of adult patients, highlighting the need to alert radiologists to this congenital anomaly.

  3. 21 CFR 882.5550 - Central nervous system fluid shunt and components.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components... Central nervous system fluid shunt and components. (a) Identification. A central nervous system fluid... central nervous system to an internal delivery site or an external receptacle for the purpose of...

  4. Calibration of piezoelectric RL shunts with explicit residual mode correction

    Høgsberg, Jan Becker; Krenk, Steen


    Piezoelectric RL (resistive-inductive) shunts are passive resonant devices used for damping of dominant vibration modes of a flexible structure and their efficiency relies on the precise calibration of the shunt components. In the present paper improved calibration accuracy is attained by an exte...

  5. Ventriculoperitoneal shunt for treatment of hydrocephalus in a French bulldog puppy.

    Giacinti, Jolene A


    A 6.5-week-old bulldog was presented with lethargy, anorexia, and stunted growth. A domed skull, ventrolateral strabismus, hypermetria, and delayed hopping were observed. Congenital hydrocephalus was diagnosed and a ventriculoperitoneal shunt was placed. After surgery, a shunt obstruction occurred but resolved with treatment. The puppy responded well and neurological deficits continued to improve after surgery.

  6. Endoscopic third ventricul ostomy versus ventricul operitoneal shunt:clinical study of obstructive hydro cephalus in infants%婴幼儿阻塞性脑积水两种手术方式的疗效比较

    江峰; 赵阳; 孙莲萍; 金惠明; 马杰


    Objective We analyzed those infant patients with obstructive hydrocephalus since 2005 in our department. The postoperative outcome was compared by follow-up data such as images and clinical finding. Methods 36 subjects were included in the study, and divided as ETV group and VP shunt group depend on the surgical procedure. We retrospectively analyzed the follow-up data such as images and clinical finding of the obstructive patients younger than 2 years old in our department since 2005 , and compare the successful rate and complication rate. Results Among 36 patients , 20 of them were treated with ETV and 16 0f them were treated with VP shunt. In ETV group , 1 infant did not get improved and suffered from CSF leakage after operation, and VP shunt was performed to avoid intracranial infection. Intraventricular hemorrhage occurred in 1 and was treated with medicine. 1 child presented with subdural hemotoma and recovered. 2 children had seizure after surgery was treated with medicine without recurrence. The complications were transient and mostly recovered, no late complication. No severe complication occurred. The early complication rate was 25% in ETV group and successful rate was 95% . In VP shunt group, 1 child presented with incranial infection, the ventricular catheter was removed to treat the infection. VP shunt was performed again after the infection was controlled. 1 case did not improve and performed ETV to control the hydrocephalus. 1 case presented with shunt malfunction and was treated with repeated VP shunt one year after the first surgery. 1 case suffered from the ventricular catheter migration and was treated with the repeated VP shunt 1 year after operation. In VP shunt group, the overall successful rate was 75% , the complication rate was 25% . Among them, the early complication rate was 6. 25% , the late complication rate was 18. 75 % , all the complications need surgery precedure. Conclusions It could be concluded that ETV is the most

  7. A rare cause of pediatric urinary incontinence: Ventriculoperitoneal shunt with bladder perforation

    Manuel C See IV


    Full Text Available We present a case of 2-year-old boy with long term dysuria and intermittent incontinence, and new onset of fever and headache. Significant past medical history includes congenital hydrocephalus with a ventriculoperitoneal shunt placement two years prior to consult. On physical examination, a tubular structure was noted underneath the prepuce suspected to be the distal tip of ventriculoperitoneal shunt, which was confirmed by kidney, ureter and bladder (KUB X-ray and CT scan. Patient was treated with a novel approach of extraperitoneal removal of ventriculoperitoneal shunt distal tip with cystorrhaphy via a low transverse pfannenstiel incision, separate left ventriculostomy tube insertion and complete removal of ventriculoperitoneal shunt from the right ventricle. This report accounts a rare pediatric case with ventriculoperitoneal shunt perforation into a normal bladder successfully treated with mini-open surgery.

  8. Tunable band gaps in acoustic metamaterials with periodic arrays of resonant shunted piezos

    Chen, Sheng-Bing; Wen, Ji-Hong; Wang, Gang; Wen, Xi-Sen


    Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a two-dimensional (2D) acoustic metamaterial. The performance is characterized by the finite element method. More importantly, we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem, and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article. Based on this modeling method, the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated. The results show that the internal resonances of the shunting system split the dispersion curves, thereby forming a locally resonant band gap. However, unlike the conventional locally resonant gap, the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches.

  9. Early mediastinal seroma secondary to modified Blalock-Taussig shunts - successful management by percutaneous drainage

    Connolly, Bairbre L.; Temple, Michael J.; Chait, Peter G.; Restrepo, Ricardo [Department of Diagnostic Imaging, Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada); Adatia, Ian [Department of Cardiology and Critical Care Medicine, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada)


    Large symptomatic mediastinal seroma following modified-BT shunts, traditionally required revisional thoracotomy. We describe percutaneous image-guided pigtail catheter drainage in the successful treatment of early mediastinal seroma secondary to PTFE Blalock-Taussig shunt, avoiding thoracotomy. A retrospective review of all relevant clinical and imaging records in five patients was performed. All five presented with intermittent stridor, respiratory distress and/or episodic desaturation within 6 weeks of their surgery. In four of five infants, percutaneous drainage was effective and reoperation was avoided. In one of five, rather than urgent surgical evacuation and BT shunt revision, we were able to perform an elective stage-II bidirectional Glenn SVC-RA anastamosis in a stable infant. There were no complications. Percutaneous image-guided drainage of mediastinal seroma secondary to PTFE-BT shunt is a safe, minimally invasive, and effective treatment. This may avoid BT shunt revision. (orig.)

  10. Tunable band gaps in acoustic metamaterials with periodic arrays of resonant shunted piezos

    Chen Sheng-Bing; Wen Ji-Hong; Wang Gang; Wen Xi-Sen


    Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a twodimensional (2D) acoustic metamaterial.The performance is characterized by the finite element method.More importantly,we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem,and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article.Based on this modeling method,the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated.The results show that the internal resonances of the shunting system split the dispersion curves,thereby forming a locally resonant band gap.However,unlike the conventional locally resonant gap,the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches.

  11. Communicating hydrocephalus due to cerebral venous sinus thrombosis treated with ventriculoperitoneal shunt

    Rahul T Chakor


    Full Text Available Cerebral venous sinus thrombosis (CVT is a rare cerebrovascular disease with variable presentation. CVT rarely causes hydrocephalus. Communicating hydrocephalus due to CVT is extremely rare. We describe a patient of CVT presenting with chronic headache and communicating hydrocephalus. The patient was successfully treated with ventriculoperitoneal (VP shunt. A 40 year old man presented with moderate to severe headache since six months and progressive visual loss since two months. Head Computed tomogram showed mild hydrocephalus without obstruction. Lumbar puncture (LP demonstrated elevated pressure but was otherwise normal. Magnetic resonance venogram showed extensive CVT. Repeated CSF drainage and thecoperitoneal shunt did not relieve the severe headache hence a VP shunt was placed. Post shunt headache subsided with resolution of hydrocephalus. CVT can present as communicating hydrocephalus. Gradual reduction of intra-ventricular pressure by repeated LPs followed by VP shunt can safely treat hydrocephalus due to CVT.

  12. Ventriculoperitoneal shunt-related infections caused by Staphylococcus epidermidis: pathogenesis and implications for treatment.

    Stevens, Niall T


    The insertion of medical devices, such as intraventricular shunts, is often complicated by infection leading to ventriculitis. Frequently, such infections result from colonisation and subsequent biofilm formation on the surfaces of the shunts by Staphylococcus epidermidis. The pathogenesis of neurosurgical shunt-related infection is complex with interactions between the pathogen, the device and the unique local immunological environment of the central nervous system (CNS). An ability to form biofilm, the main virulence determinant of Staphylococcus epidermidis, facilitates protection of the organism from the host defences while still initiating an immunological response. The presence of the blood brain barrier (BBB) and the biofilm itself also complicates treatment, which presents many challenges when managing shunt infections. A greater understanding of the interplay between S. epidermidis and the CNS could potentially improve the diagnosis, treatment and management of such infections. This review describes the pathogenesis, treatment and implications of S. epidermidis ventriculoperitoneal shunt-related infections, concentrating on recent research and the implications for treatment.

  13. Clinical and ultrasonographic criteria for using ventriculoperitoneal shunts in newborns with myelomeningocele

    Jose Roberto Tude Melo


    Full Text Available Objective Hydrocephalus is one of the main complications associated with myelomeningocele (MM. This study aimed to identify clinical and ultrasonographic criteria for using ventriculoperitoneal (VP shunts in this group of patients.Method A retrospective cohort study, based on established protocol for VP shunt implant in hydrocephalic children with MM. Parameters used to guide the indication of VP shunts included measurement of head circumference (HC, evaluation of fontanels, and measurement of lateral ventricular atrium (LVA width by transcranial ultrasonography.Results 43 children were included in the analysis, of which 74% had hydrocephalus and required a VP shunt. These children had LVA width ≥ 15 mm, showed increased HC, or had bulging fontanels.Conclusion VP shunt is required in children with increased HC (≥ 2 standard deviation regarding age group, bulging fontanels, or LVA width of ≥ 15 mm after the closure of MM.

  14. Fabrication and characterization of shunted μ-SQUID

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.


    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  15. Rex shunt preoperative imaging: diagnostic capability of imaging modalities.

    Sharon W Kwan

    Full Text Available The purpose of this study was to evaluate the diagnostic capability of imaging modalities used for preoperative mesenteric-left portal bypass ("Rex shunt" planning. Twenty patients with extrahepatic portal vein thrombosis underwent 57 preoperative planning abdominal imaging studies. Two readers retrospectively reviewed these studies for an ability to confidently determine left portal vein (PV patency, superior mesenteric vein (SMV patency, and intrahepatic left and right PV contiguity. In this study, computed tomographic arterial portography allowed for confident characterization of left PV patency, SMV patency and left and right PV continuity in 100% of the examinations. Single phase contrast-enhanced CT, multi-phase contrast-enhanced CT, multiphase contrast-enhanced MRI, and transarterial portography answered all key diagnostic questions in 33%, 30%, 0% and 8% of the examinations, respectively. In conclusion, of the variety of imaging modalities that have been employed for Rex shunt preoperative planning, computed tomographic arterial portography most reliably allows for assessment of left PV patency, SMV patency, and left and right PV contiguity in a single study.

  16. Fabrication and characterization of shunted μ-SQUID

    Kumar, Nikhil, E-mail: [Department of Physics, Indian Institute of Technology Kanpur - 208016 (India); Fournier, T.; Courtois, H.; Gupta, Anjan K. [Institute Neel, CNRS and Université Joseph Fourier, 25 Avenue des Martyrs, BP 166, 38042, Grenoble (France)


    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good I{sub c} vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function V{sub Φ} = 7.2mV/Φ{sub 0}. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  17. Choice of valve type and poor ventricular catheter placement: Modifiable factors associated with ventriculoperitoneal shunt failure.

    Jeremiah, Kealeboga Josephine; Cherry, Catherine Louise; Wan, Kai Rui; Toy, Jennifer Ah; Wolfe, Rory; Danks, Robert Andrew


    Ventriculoperitoneal (VP) shunt insertion is a common neurosurgical procedure, essentially unchanged in recent years, with high revision rates. We aimed to identify potentially modifiable associations with shunt failure. One hundred and forty patients who underwent insertion of a VP shunt from 2005-2009 were followed for 5-9years. Age at shunt insertion ranged from 0 to 91years (median 44, 26% hydrocephalus were congenital (26%), tumour-related (25%), post-haemorrhagic (24%) or normal pressure hydrocephalus (19%). Fifty-eight (42%) patients required ⩾1 shunt revision. Of these, 50 (88%) were for proximal catheter blockage. The median time to first revision was 108days. Early post-operative CT scans were available in 105 patients. Using a formal grading system, catheter placement was considered excellent in 49 (47%) but poor (extraventricular) in 13 (12%). On univariate analysis, younger age, poor ventricular catheter placement and use of a non-programmable valve were associated with shunt failure. On logistic regression modelling, the independent associations with VP shunt failure were poor catheter placement (odds ratio [OR] 4.9, 95% confidence interval [CI] 1.3-18.9, p=0.02) and use of a non-programmable valve (OR 0.4, 95% CI 0.2-1.0, p=0.04). In conclusion, poor catheter placement (revision rate 77%) was found to be the strongest predictor of shunt failure, with no difference in revisions between excellent (43%) and moderate (43%) catheter placement. Avoiding poor placement in those with mild or moderate ventriculomegaly may best reduce VP shunt failures. There may also be an influence of valve choice on VP shunt survival.

  18. bir1 deletion causes malfunction of the spindle assembly checkpoint and apoptosis in yeast

    Qun eRen


    Full Text Available Cell division in yeast is a highly regulated and well studied event. Various checkpoints are placed throughout the cell cycle to ensure faithful segregation of sister chromatids. Unexpected events, such as DNA damage or oxidative stress, cause the activation of checkpoint(s and cell cycle arrest. Malfunction of the checkpoints may induce cell death. We previously showed that under oxidative stress, the budding yeast cohesin Mcd1, a homolog of human Rad21, was cleaved by the caspase-like protease Esp1. The cleaved Mcd1 C-terminal fragment was then translocated to mitochondria, causing apoptotic cell death. In the present study, we demonstrated that Bir1 plays an important role in spindle assembly checkpoint and cell death. Similar to H2O2 treatment, deletion of BIR1 using a BIR1-degron strain caused degradation of the securin Pds1, which binds and inactivates Esp1 until metaphase-anaphase transition in a normal cell cycle. BIR1 deletion caused an increase level of ROS and mis-location of Bub1, a major protein for spindle assembly checkpoint. In wild type, Bub1 was located at the kinetochores, but was primarily in the cytoplasm in bir1 deletion strain. When BIR1 was deleted, addition of nocodazole was unable to retain the Bub1 localization on kietochores, further suggesting that Bir1 is required to activate and maintain the spindle assembly checkpoint. Our study suggests that the BIR1 function in cell cycle regulation works in concert with its anti-apoptosis function.

  19. Diagnosis and treatment of early bioprosthetic malfunction in the mitral valve position due to thrombus formation.

    Butnaru, Adi; Shaheen, Joseph; Tzivoni, Dan; Tauber, Rachel; Bitran, Daniel; Silberman, Shuli


    Bioprosthetic valve thrombosis is uncommon and the diagnosis is often elusive and may be confused with valve degeneration. We report our experience with mitral bioprosthetic valve thrombosis and suggest a therapeutic approach. From 2002 to 2011, 149 consecutive patients who underwent mitral valve replacement with a bioprosthesis at a single center were retrospectively screened for clinical or echocardiographic evidence of valve malfunction. Nine were found to have valve thrombus. All 9 patients had their native valve preserved, representing 24% of those with preserved native valves. Five patients (group 1) presented with symptoms of congestive heart failure at 16.4 ± 12.4 months after surgery. Echocardiogram revealed homogenous echo-dense film on the ventricular surface of the bioprosthesis with elevated transvalvular gradient, resembling early degeneration. The first 2 patients underwent reoperation: valve thrombus was found and confirmed by histologic examination. Based on these, the subsequent 3 patients received anticoagulation treatment with complete thrombus resolution: mean mitral gradient decreased from 23 ± 4 to 6 ± 1 mm Hg and tricuspid regurgitation gradient decreased from 83 ± 20 to 49 ± 5 mm Hg. Four patients (group 2) were asymptomatic, but routine echocardiogram showed a discrete mass on the ventricular aspect of the valve: 1 underwent reoperation to replace the valve and 3 received anticoagulation with complete resolution of the echocardiographic findings. In conclusion, bioprosthetic mitral thrombosis occurs in about 6% of cases. In our experience, onset is early, before anticipated valve degeneration. Clinical awareness followed by an initial trial with anticoagulation is warranted. Surgery should be reserved for those who are not responsive or patients in whom the hemodynamic status does not allow delay. Nonresection of the native valve at the initial operation may play a role in the origin of this entity.

  20. Distal splenorenal shunt with splenopancreatic disconnection for portal hypertension in biliary atresia.

    Hasegawa, T; Tamada, H; Fukui, Y; Tanano, H; Okada, A


    This study evaluated the long-term effects of distal splenorenal shunt with splenopancreatic disconnection (DSRS-SPD) on portal hypertension (PH) in biliary atresia (BA) patients. Five patients with BA underwent DSRS-SPD at the age of 3.3 to 8.5 years. They had been free from jaundice after hepatic portoenterostomy (HPE); however, they gradually developed gastroesophageal varices and hypersplenism. Portal venous pressure after anastomosis was 37.2 +/- 6.1 cmH2O, as high as that before anastomosis (37.8 +/- 3.3 cmH2O). Postoperatively, liver function tests became worse within 2 weeks; however, they returned to preoperative levels within 1 month without any further treatment. No patient developed a significant encephalopathy throughout the observed period. During follow-up of 4 to 12 years, the shunt was patent in all patients. Spleen size decreased after operation. Abdominal-wall venous dilatation completely disappeared in two of four patients. The platelet counts gradually increased and were significantly higher 3 years (126.6 +/- 59.3 x 10(3)/mm3) after DSRS-SPD than preoperative values (66.0 +/- 24.2 x 10(3)/mm3). White blood cell counts showed no significant changes. No patient developed a gastrointestinal hemorrhage postoperatively, although three had had repeated hemorrhages before the operation. Two patients showed disappearance of varices endoscopically at 2 years and 7 months after DSRS-SPD, respectively, but had recurrent varices at 7 and 11 years, respectively. The endoscopic findings regarding varices 3 to 7 years after DSRS-SPD were as follows: decreased number (80%); decreased length (40%); improvement of form (20%); improvement of fundamental color (60%); disappearance of red-color sign (100%); disappearance of gastric varices (75%); and disappearance of acute gastric mucosal lesions (100%). Although one patient later underwent liver transplantation because of progression of liver cirrhosis, all five are doing well. From these results, DSRS-SPD may

  1. Prone positioning ventilation for treatment of acute lung injury and acute respiratory distress syndrome

    LAN Mei-juan; HE Xiao-di


    Patients who are diagnosed with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) usually have ventilation-perfusion mismatch, severe decrease in lung capacity, and gas exchange abnormalities. Health care work-ers have implemented various strategies in an attempt to compensate for these pathological alterations. By rotating patients with ALI/ARDS between the supine and prone position, it is possible to achieve a significant improvement in PaO2/FiO2, decrease shunting and therefore improve oxy-genation without use of expensive, invasive and experimen-tal procedures.

  2. A Rare Complication of Acute Otitis Media: Otitic Hydrocephalus

    Ahmet Mutlu


    Full Text Available Acute otitis media is very common disorder in childhood. In this article we present a 6-years old boy who applied with diplopia, dysfunction of lateral eye movements on left eye, nausea, at 10th day of acute otitis media treatment. After the radiological images case was described as an otitic hydrocephalus clinic. Patient underwent medical treatment, lomboperitoneal shunt operation and simple mastoidectomy. We wanted to share the evaluation and the management steps of this very rare complication of acute otitis media.

  3. Laparoscopic distal splenoadrenal shunt for the treatment of portal hypertension in children with congenital hepatic fibrosis

    Zhang, Jin-Shan; Cheng, Wei; Li, Long


    Abstract Background: The distal splenorenal shunt is an effective procedure for the treatment of portal hypertension in children. However, there has been no report about laparoscopic distal splenorenal shunt in the treatment of portal hypertension in children. Methods: From December 2015 to August 2016, 4 children with upper gastrointestinal bleeding underwent laparoscopic distal splenoadrenal shunt. Portal hypertension and splenomegaly were demonstrated on the preoperative computed tomography (CT) and sonography. The distal splenic vein was mobilized and anastomosed to the left adrenal vein laparoscopically. All patients were followed-up postoperatively. Results: The laparoscopic distal splenoadrenal shunt was successfully performed in all patients. The liver fibrosis was diagnosed by postoperative liver pathology. The operative time ranged from 180 to 360 minutes. The blood loss was minimal. The length of hospital stay was 6 to 13 days. The duration of following-up was 1 to 9 months (median: 3 months). The portal pressure and splenic size were decreased postoperatively. The complete blood count normalized and the biochemistry tests were within normal range after surgery. Postoperative ultrasound and CT confirmed shunt patency and satisfactory flow in the splenoadrenal shunt in all patients. No patient developed recurrence of variceal bleeding. Conclusions: The laparoscopic splenoadrenal shunt is a feasible treatment of portal hypertension in children. PMID:28099341

  4. Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

    Arielle Spitze


    Full Text Available Background: Idiopathic intracranial hypertension (IIH has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option - optic nerve sheath fenestration (ONSF or cerebrospinal fluid (CSF shunting - for the long-term treatment of this syndrome. Purpose: To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH. Design: This was a retrospective review of the current literature in the English language indexed in PubMed. Methods: The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics. Results: The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache. Conclusion: The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway. This article will hopefully be helpful in allowing the reader to make a more informed decision until that time.

  5. Damping Analyses of Structural Vibrations and Shunted Piezoelectric Transducers

    Saber Mohammadi


    Full Text Available Piezoelectric transducers in conjunction with appropriate electric networks can be used as a mechanical energy dissipation device. Alternatively, undesired mechanical energy of a structure could be converted into electrical energy that can be dissipated through a shunt network in the form of Joule heating. This paper presents an experimental method to calculate damping energy in mechanical systems. However, the mathematical description of damping mechanism is much more complicated, and any process responsible for the occurrence of damping is very intricate. Structural and piezoelectric damping are calculated and analysed in the case of pulse switching or SSDI semiactive vibration control technique. This technique which was developed in the field of piezoelectric damping consists in triggering the inverting switch on each extremum of the piezoelectric voltage which induces an increase of the electromechanical energy conversion.

  6. Analysis of new actuation methods for capacitive shunt micro switchs

    Ben Sassi S


    Full Text Available This work investigates the use of new actuation methods in capacitive shunt micro switches. We formulate the coupled electromechanical problem by taking into account the fringing effects and nonlinearities due to mid-plane stretching. Static analysis is undertaken using the Differential Quadrature Method (DQM to obtain the pull in voltage which is verified by means of the Finite Element Method (FEM. Based on Galerkin approximation, a single degree of freedom dynamic model is developed and limit-cycle solutions are calculated using the Finite Difference Method (FDM. In addition to the harmonic waveform signal, we apply novel actuation waveform signals to simulate the frequency-response. We show that, biased signals, using a square wave signal reduces significantly the pull-in voltage compared to the triangular and harmonic signal . Finally, these results are validated experimentally.

  7. Failure of peritoneal and gallbladder shunts in a child with craniopharyngioma

    Julie Woodfield


    Full Text Available A 1-year-old girl with craniopharyngioma required external drainage of 40-50 mL/h of cerebrospinal fluid (CSF after biopsy and cyst fenestration. She developed CSF ascites following insertion of a ventriculoperitoneal (VP shunt and a distended painful gallbladder following ventriculogallbladder shunt insertion. Revision to a ventriculoatrial shunt was required. This is the first time a craniopharyngioma has been reported to cause increased CSF production. The potential mechanisms of CSF overproduction and the difficulties managing the large volume of CSF in a young child are discussed.

  8. Simulation and reliability analysis of shunt active power filter based on instantaneous reactive power theory

    CUI Yu-long; LIU Hong; WANG Jing-qin; SUN Shu-guang


    This paper first discusses the operating principle ofinstantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyfistor bridge rectifier circuit is constructed.The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme.

  9. Intrahepatic portosystemic venous shunts: diagnosis by Doppler ultrasound; Cortocircuitos venosos portosistemicos intrahepaticos: diagnostico mediante ecografia Doppler

    Garofano, M. P.; Medina, A.; Lopez, G.; Garrido, C. [Hospital Universitario Virgen de las Nieves. Granada (Spain)


    Intrahepatic portosystemic venous shunts are venous vascular lesions that allow intrahepatic portal vessels to communicate with hepatic veins. They may present in patients with portal hypertension or b discovered incidentally; it is considered that the latter may be congenital or acquired. A noninvasive methods. Doppler ultrasound aids in the diagnosis of these anomalous communications by providing images of the vessels and the direction, velocity and volume of the blood flow through the shunt. We present four cases of intrahepatic portosystemic venous shunt. (Author) 8 refs.

  10. Hyperchaotic behaviours and controlling hyperchaos in an array of RCL-shunted Josephson junctions

    Ri Ilmyong; Feng Yu-Ling; Yao Zhi-Hai; Fan Jian


    This paper deals with dynamical behaviours in an array composed of two resistive-capacitive-inductive-shunted (RCL-shunted) Josephson junctions (RCLSJJs) and a shunted resistor.Numerical simulations show that periodic,chaotic and hyperchaotic states can coexist in this array.Moreover,a scheme for controlling hyperchaos in this array is presented by adjusting the external bias current.Numerical results confirm that this scheme can be effectively used to control hyperchaotic states in this array into stable periodic states,and different stable periodic states with different period numbers can be obtained by appropriately choosing the intensity of the external bias current.

  11. Design and Simulation of a Shunt Active Filter in Application for Control of Harmonic Levels

    Adrian, Gligor


    Nowadays, the active filters represent a viable alternative for controlling harmonic levels in industrial consumers electrical installations. It must be noted the availability of many different types of filter configurations that can be used but there is no standard method for rating the active filters. This paper focuses on describing the shunt active filter structure and design. The theoretical concepts underlying the design of shunt active filters are presented. To validate and highlight the performance of shunt active filters a Matlab-Simulink model was developed. Simulation results are also presented.

  12. Waste Package Neutron Absorber, Thermal Shunt, and Fill Gas Selection Report

    V. Pasupathi


    Materials for neutron absorber, thermal shunt, and fill gas for use in the waste package were selected using a qualitative approach. For each component, selection criteria were identified; candidate materials were selected; and candidates were evaluated against these criteria. The neutron absorber materials evaluated were essentially boron-containing stainless steels. Two candidates were evaluated for the thermal shunt material. The fill gas candidates were common gases such as helium, argon, nitrogen, carbon dioxide, and dry air. Based on the performance of each candidate against the criteria, the following selections were made: Neutron absorber--Neutronit A978; Thermal shunt--Aluminum 6061 or 6063; and Fill gas--Helium.

  13. Liver resection for the treatment of a congenital intrahepatic portosystemic venous shunt

    Michail Papamichail; Amir Ali; Alberto Quaglia; John Karani; Nigel Heaton


    Intrahepatic portosystemic shunts (IPSS) are rare congenital anomalies arising from disordered portal vein em-bryogenesis. It has been described in both children and adults and may be asymptomatic or be associated with a variety of neurophysiological and pulmonary complications. When rec-ognized, early intervention to occlude the shunt will reverse the associated complications. Literature review reports of surgical and radiological occlusion of the shunt, but due to its rarity, a standard therapeutic protocol has not been established. A case of a 38-year-old woman with abdominal pain and low grade encephalopathy, diagnosed with an IPSS and treated by right hepatectomy was reported.

  14. Lack of shunt response in suspected idiopathic normal pressure hydrocephalus with Alzheimer disease pathology.

    Hamilton, Roy; Patel, Sunil; Lee, Edward B; Jackson, Eric M; Lopinto, Joanna; Arnold, Steven E; Clark, Christopher M; Basil, Anuj; Shaw, Leslie M; Xie, Sharon X; Grady, M Sean; Trojanowski, John Q


    To determine the impact of cortical Alzheimer disease pathology on shunt responsiveness in individuals treated for idiopathic normal pressure hydrocephalus (iNPH), 37 patients clinically diagnosed with iNPH participated in a prospective study in which performance on neurologic, psychometric, and gait measures before and 4 months after shunting was correlated with amyloid β plaques, neuritic plaques, and neurofibrillary tangles observed in cortical biopsies obtained during shunt insertion. No complications resulted from biopsy acquisition. Moderate to severe pathology was associated with worse baseline cognitive performance and diminished postoperative improvement on NPH symptom severity scales, gait measures, and cognitive instruments compared to patients lacking pathology.

  15. Intrahepatic Portosystemic Venous Shunt: Successful Embolization Using the Amplatzer Vascular Plug II

    Lee, Young Ju; Shin, Byung Seok; Lee, In Ho; Ohm, Joon Young; Lee, Byung Seok; Ahn, Moon Sang [Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon (Korea, Republic of); Kim, Ho Jun [Dept. of Radiology, Konyang University Hospital, Konyang University College of Medicine, Daejeon (Korea, Republic of)


    A 67-year-old woman presented with memory impairment and behavioral changes. Brain MRI indicated hepatic encephalopathy. Abdominal CT scans revealed an intrahepatic portosystemic venous shunt that consisted of two shunt tracts to the aneurysmal sac that communicated directly with the right hepatic vein. The large tract was successfully occluded by embolization using the newly available AMPLATZERTM Vascular Plug II and the small tract was occluded by using coils. The patient's symptoms disappeared after shunt closure and she remained free of recurrence at the 3-month follow-up evaluation.

  16. Finite Element and Experimental Study of Shunting in Resistance Spot Welding

    Seyyedian Choobi, M.; Nielsen, C. V.; Bay, N.


    conducted to investigate the effect of shunting on nugget size in spot welding of HSLA steel sheets. Different cases with different spacing between weld spots have been examined. The nugget sizes have been measured by metallographic examination and have been compared with 3D finite element simulations....... The results of this study revealed that the shunt effect becomes negligible when the minimum weld spacing is about six times the electrode diameter. The results showed that the weld nugget diameter is more sensitive to shunt effect than the nugget height....

  17. Liver resection for the treatment of a congenital intrahepatic portosystemic venous shunt

    Michail Papamichail; Amir Ali; Alberto Quaglia; John Karani; Nigel Heaton


    Intrahepatic portosystemic shunts (IPSS) are rare congenital anomalies arising from disordered portal vein em-bryogenesis. It has been described in both children and adults and may be asymptomatic or be associated with a variety of neurophysiological and pulmonary complications. When rec-ognized, early intervention to occlude the shunt will reverse the associated complications. Literature review reports of surgical and radiological occlusion of the shunt, but due to its rarity, a standard therapeutic protocol has not been established. A case of a 38-year-old woman with abdominal pain and low grade encephalopathy, diagnosed with an IPSS and treated by right hepatectomy was reported.

  18. 脑室-腹腔分流术后迟发性颅内出血8例临床分析%Clinical analysis of 8 patients with delayed intracranial hemorrhage after ventricular-peritoneal shunt for hydrocephalus

    金浩; 张卫; 朱扬清; 邹煜; 周秋锋; 刘星; 钱伟; 左常阳


    目的:探讨脑室-腹腔分流术后出现迟发性颅内出血的类型,以及可能的防治措施。方法对72例脑室-腹腔分流术患者进行回顾性分析,分析术后发生迟发性颅内出血的规律和原因。结果本组患者中发生术后迟发性颅内血肿8例,急性硬膜下血肿2例、慢性硬膜下血肿2例及脑内血肿4例,是脑室-腹腔分流术后主要的三类迟发性颅内出血。结论选择合适的分流管、调整合适阀门压力以及熟练掌握脑室穿刺技巧可以减少及避免出现脑室-腹腔分流术后迟发性颅内出血。%Objective To explore the types of delayed intracranial hemorrhage after ventricular-peritoneal shunt for hydrocephalus , as well as effective prevention and control measures .Methods The clinical data of 72 patients suffered from delayed intracranial hemorrhage by ventricular-peritoneal shunt were analyzed retrospectively .The clinical features and factors were also analyzed .Results There were 8 cases of delayed intracranial hemorrhage after ventricular-peritoneal shunt in this group .The acute subdural hematoma , chronic subdural hematoma and intracerebral hemorrhage were the majory types of delayed intracranial emorrhage after ventricular -peritoneal shunt for hydrocephalus . Conclusion Choose the right shunt system , adjust the appropriate pressure and master the ventricle puncture techniques can reduce and avoid delayed intracranial hemorrhage .

  19. Severe Intraoperative Hypercapnia Complicating an Unsual Malfunction of the Inner Tube of a Co-axial (BAIN'S Circuit

    Youssef Emam Youssef


    Full Text Available The Bain's co-axial circuit system is fully established in general anaesthesia practice. It is favoured for its light weight and suitability for head and neck surgery. However, there are numerous published reports of malfunction of the inner tube of the Bain's co-axial circuit, with potentially lethal complications for the patient. This report presents a case in which a patient connected to a reused Bain's circuit (Datex-Ohmeda developed severe hypercapnia in the early intraoperative period due to unusual defect of the inner tube. This report tests and outlines the integrity of co-axial circuits and also reviews the available literature.

  20. Obstructed surgical porto-systemic shunts in the early postoperative period: interventional therapy by angioplasty (PTA) and stent placement; Obstruktion chirurgischer portosystemischer Shunts in der fruehen postoperativen Phase: interventionelle Behandlung durch Angioplastie und Stentimplantation

    Strunk, H.; Textor, J.; Koenig, R.; Wilhelm, K.; Schild, H. [Bonn Univ. (Germany). Radiologische Klinik; Wolff, M. [Bonn Univ. (Germany). Chirurgische Klinik und Poliklinik


    Recurrent variceal bleeding in patients treated with surgical porto-systemic shunting is most often due to shunt stenoses or occlusion. Radiological interventional procedures are a possible method of therapy and our experience herein is described in this report. Patients and Methods: from 1997 to 1999 54 patients with recurrent variceal bleeding were treated with a surgical porto-systemic shunt procedure. Of these early shunt occlusion occurred in 5 patients, which was treated with percutaneous transcatheter techniques. Results: in only one patient was PTA alone sufficient to reestablish shunt patency, in four patient stent placement was necessary in addition. In the follow-up period 1 patient died 26 month after intervention with (autopsy-proven) patent shunt, in one patient shunt reocclusion occurred after 11 months and in 3 patients the shunt is still patent. Conclusions: PTA, if necessary in combination with stent placement, is an attractive alternative method of therapy in case of an early surgical porto-systemic shunt occlusion. (orig.) [German] Rezidivblutungen nach chirurgischer portosystemischer Shuntanlage sind meistens durch eine Shuntstenose oder einen Shuntverschluss bedingt. Hier stellen interventionelle Eingriffe einen moeglichen therapeutischen Ansatz dar, ueber den im Folgenden berichtet werden soll. Patienten und Methode: zwischen 1997 und 1999 wurde bei insgesamt 54 Patienten wegen rezidivierender Blutungen ein operativer portosystemischer Shunt angelegt. Von diesen zeigten fuenf Patienten in der unmittelbaren postoperativen Periode einen Shuntverschluss, der radiologisch interventionell therapiert wurde. Ergebnisse: bei einem der fuenf Patienten genuegte zur Wiederherstellung des Flusses eine alleinige Ballondilatation (PTA), bei vier Patienten musste zusaetzlich eine Stentimplantation durchgefuehrt werden. In der weiteren Nachsorge ist ein Pat. nach 26 Wochen mit autoptisch offenem Shunt verstorben, bei 3 Pat. ist der Shunt offen, bei einem

  1. Racial and socioeconomic disparities in outcomes following pediatric cerebrospinal fluid shunt procedures.

    Attenello, Frank J; Ng, Alvin; Wen, Timothy; Cen, Steven Y; Sanossian, Nerses; Amar, Arun P; Zada, Gabriel; Krieger, Mark D; McComb, J Gordon; Mack, William J


    OBJECT Racial and socioeconomic disparities within the US health care system are a growing concern. Despite extensive research and efforts to narrow such disparities, minorities and economically disadvantaged patients continue to exhibit inferior health care outcomes. Disparities in the delivery of pediatric neurosurgical care are understudied. Authors of this study examine the impact of race and socioeconomic status on outcomes following pediatric CSF shunting procedures. METHODS Discharge information from the 2000, 2003, 2006, and 2009 Kids' Inpatient Database for individuals (age hydrocephalus who had undergone CSF shunting procedures was abstracted for analysis. Multivariate logistic regression analyses, adjusting for patient and hospital factors and annual CSF shunt procedure volume, were performed to evaluate the effects of race and payer status on the likelihood of inpatient mortality and nonroutine hospital discharge (that is, not to home). RESULTS African American patients (p shunting procedures. Further studies on health disparities in this population are warranted.

  2. Subdural haematoma complicating shunting for normal pressure hydrocephalus in the setting of concomitant antiplatelet medication

    Birkeland, Peter; Lauritsen, Jens; Poulsen, Frantz Rom


    OBJECTIVE: To report on the occurrence and management of subdural haematoma after shunt implantation for normal pressure hydrocephalus and to determine the risk of recurrence in the setting of antiplatelet medication. METHODS: From a consecutive series of 80 patients implanted with a cerebrospinal...... fluid shunt for normal pressure hydrocephalus, records from 11 patients taking antiplatelet drugs, who subsequently had surgery for subdural haematoma were extracted and retrospectively reviewed. RESULTS: Patients were followed up for a mean of 1819 days after shunt implantation. Subdural haematomas...... reoperations done before the subdural collection disappeared. Only one patient had a late recurrence almost 11 years after shunt implantation. CONCLUSIONS: Subdural haematoma in the setting of a ventriculoperitoneal implantation for normal pressure hydrocephalus and concomitant antiplatelet medication can...

  3. Surgical attenuation of spontaneous congenital portosystemic shunts in dogs resolves hepatic encephalopathy but not hypermanganesemia.

    Gow, Adam G; Frowde, Polly E; Elwood, Clive M; Burton, Carolyn A; Powell, Roger M; Tappin, Simon W; Foale, Rob D; Duncan, Andrew; Mellanby, Richard J


    Hypermanganesemia is commonly recognized in human patients with hepatic insufficiency and portosystemic shunting. Since manganese is neurotoxic, increases in brain manganese concentrations have been implicated in the development of hepatic encephalopathy although a direct causative role has yet to be demonstrated. Evaluate manganese concentrations in dogs with a naturally occurring congenital shunt before and after attenuation as well as longitudinally following the changes in hepatic encephalopathy grade. Our study demonstrated that attenuation of the shunt resolved encephalopathy, significantly reduced postprandial bile acids, yet a hypermanganasemic state persisted. This study demonstrates that resolution of hepatic encephalopathy can occur without the correction of hypermanganesemia, indicating that increased manganese concentrations alone do not play a causative role in encephalopathy. Our study further demonstrates the value of the canine congenital portosystemic shunt as a naturally occurring spontaneous model of human hepatic encephalopathy.

  4. Laparoscopic Cholecystectomy for a Patient with a Lumboperitoneal Shunt: A Rare Case.

    Rumba, Roberts; Vanags, Andrejs; Strumfa, Ilze; Pupkevics, Andrejs; Pavars, Maris


    A rare factor that can complicate the perioperative course of laparoscopic cholecystectomy is previous placement of a lumboperitoneal (LP) shunt. Thus far, only two articles describing this situation have been published. Here, we report on a 41-year-old female patient with gallstone disease and a LP shunt placement in the preceding year due to idiopathic intracranial hypertension. It is a syndrome of increased intracranial pressure without any known cause that mainly affects young obese women. The patient was operated upon using standard port placement and peritoneal insufflation. The postoperative period was uneventful and the patient was discharged shortly after the procedure. Due to the increasing incidence and prevalence of obesity, the number of general surgical patients with a LP shunt will likely increase. Based on our experience and evidence in the literature, we conclude that performing a laparoscopy for a patient with a LP shunt is safe.

  5. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm

    Jin, Junchen


    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  6. Assessment of FGPM shunt damping for vibration reduction of laminated composite beams

    Lezgy-Nazargah, M.; Divandar, S. M.; Vidal, P.; Polit, O.


    This work addresses theoretical and finite element investigations of functionally graded piezoelectric materials (FGPMs) for shunted passive vibration damping of laminated composite beams. The properties of piezoelectric patches are assumed to vary through the thickness direction following the exponent or power law distribution in terms of the volume fractions of the constituent materials. By employing Hamilton's principle, the governing differential equations of motion are derived. The resulting system of equations of vibration is solved by employing an efficient three-nodded beam element which is based on a refined sinus piezoelectric model. The effects of effective electromechanical coupling coefficients (EEMCCs), different electric shunt circuits and different material compositions on the shunted damping performance are investigated. The optimal values of the electric components belonging to each shunt circuit are numerically determined.

  7. Experimental study on absorption of blade vibration of honeycomb seal and shunt injection

    Zhang Qiang; He Lidong; Huo Genglei; Che Jianye


    Honeycomb seals and shunt injection have been proposed to weaken the blade vibration. Honeycomb seals, as well as, smooth seals were tested with different seals' clearances and shrouded blades. The shunt injection was sprayed to the blade tip clearance in the reverse direction of the main flow. Experimental results showed that both honeycomb seals and shunt injection had the damping effect for blade vibration, and the blade vibration magnitude could be reduced by more than 25% and 17%, respectively. When the two methods were adopted synchronously, more than 1/3 of the blade vibration could be reduced. Consequently, adopting honeycomb seal and superinducing proper shunt injection are two useful ways to minimize vibration of the blade from the viewpoints of avoiding blade rupture and improving the rotor stability.

  8. Shunt hybrid active power filter for harmonic mitigation: A practical design approach

    Unnikrishnan A K; Chandira Sekaran E; Subhash Joshi T G; Manju A S; Aby Joseph


    The increasing importance of Power Quality problems has been responsible for several improvements in Active Power Filter (APF) typologies in the last decade. The increased cost and switching losses make a pure shunt APF economically impractical for high power applications. In higher power levels shunt Hybrid Active Power Filter (HAPF) has been reported to be a useful approach to eliminate current harmonics caused by nonlinear loads. This paper presents a control strategy and design criteria for transformer-less shunt HAPF with special attention to the integration of series passive filter. The paper also compares the performance improvement of passive harmonic filter when modified as shunt HAPF. Experimental results obtained verify the viability and effectiveness of the proposed design criteria and control algorithm.

  9. Cardiac and renal effects of a transjugular intrahepatic portosystemic shunt in cirrhosis

    Busk, Troels M; Bendtsen, Flemming; Møller, Søren


    Refractory ascites and recurrent variceal bleeding are among the serious complications of portal hypertension and cirrhosis for which a transjugular intrahepatic portosystemic shunt (TIPS) can be used. Cirrhotic patients have varying degrees of haemodynamic derangement, mainly characterized...

  10. Effects of quaternary ammonium silane coatings on mixed fungal and bacterial biofilms on tracheoesophageal shunt prostheses

    Oosterhof, JJH; Buijssen, KJDA; Busscher, HJ; van der Laan, BFAM; van der Mei, HC


    Two quaternary ammonium silanes (QAS) were used to coat silicone rubber tracheoesophageal shunt prostheses, yielding a positively charged surface. One QAS coating [(trimethoxysilyl)-propyidimethylocta-decylammonium chloride] was applied through chemical bonding, while the other coating, Biocidal ZF,

  11. Primary shunt hyperbilirubinaemia in a large four-generation family confirming autosomal dominant genetic disorder

    Chun-Lian Wang; Xiao-Wei Liu; Fang-Gen Lu; Xiao-Ping Wu; Chun-Hui Ouyang; Dong-Ye Yang


    AIM: To describe the pattern of inheritance and confirm the diagnosdc criteria of primary shunt hyperbilirubinaemia (PSH).METHODS: Forty members of a family pedigree across four generations were included in this study. All family members were interviewed and investigated by physical examination, hematology and liver function test and the pattern of inheritance was analyzed.RESULTS: Nine of the forty family members suffered primary shunt hyperbilirubinaemia. The mature erythrocytes of the propositus were irregular in shape and size.The pedigree showed transmission of the trait through four generations with equal distribution in male and female. No individual with a primary shunt hyperbilirubinaemia was born to unaffected parents. The penetrance was complete in adult.CONCLUSION: The pattern of inheritance is autosomal dominant. The abnormality of erythrocytes and decrease in white blood cell could be supplemented in the diagnosis of PSH. The PSH is a genetic disorder and could by renamed as hereditary shunt hyperbilirubinaemia.

  12. Initial brain CT scan and shunting outcomes in children with hydrocephalus

    Andi Anita Utami


    Full Text Available Background Hydrocephalus is one of the most common clinical conditions affecting the central nervous system, with a congenital hydrocephalus incidence of 3-4 per 1000 births. Incidence of acquired types of hydrocephalus is unknown. Brain computerised tomography (CT scan can be used to assess the size of ventricles and other structures. Shunting has long been performed to alleviate hydrocephalus. Shunting has dramatically changed the outlook of children with hydrocephalus, with many of them having normal life expectancies and attaining normal intelligence. Objective To determine the outcomes of shunting in children with hydrocephalus based on initial brain CT scan. Methods We performed a cross-sectional study in Dr. Kariadi Hospital. Initial brain CT scan data were collected from the medical records of children admitted to the Neurosurgery Ward for ventriculoperitoneal (VP shunt surgery from January 2009 to December 2010. We studied the brain CT scan findings before VP shunt surgery and the outcomes of the children after VP shunt surgery. Radiological findings were determined by a radiologist responsible at that time. Results This study consisted of 30 subjects, 19 boys and 11 girls. Initial brain CT scans to assess disease severity revealed the following conditions: lateral ventricle dilatation in 7 subjects, lateral and third ventricle dilatation in 16 subjects, and lateral, third and fourth ventricle dilatation in 7 subjects. After VP shunt surgery, 3 subjects in the lateral, third and fourth ventricle dilatation category died. They were grouped according to their condition. Group 1 consisted of subjects with only lateral ventricle dilatation and subjects with lateral and third ventricle dilatation (23 subjects, while group 2 consisted of subjects with lateral, third and fourth ventricle dilatation (7 subjects. More survivors were found in group 1 than those in group 2. Conclusion Less severe initial brain CT scan findings are associated with

  13. Bilateral subdural effusion and subcutaneous swelling with normally functioning csf shunt.

    Mitra S


    Full Text Available We report a child with hydrocephalus due to tuberculous meningitis who developed a subcutaneous fluid collection around the ventriculoperitoneal shunt tube entry point, after one month of shunting. On investigation, he had decompressed ventricles with bilateral fronto parietal subdural hygroma. Bifrontal burr hole drainage helped resolution of both subdural effusion and subcutaneous scalp swelling. This complication is unique and its pathogenesis has been postulated.

  14. Penile Gangrene with Abscess Formation after Modified Al-Ghorab Shunt for Idiopathic Ischemic Priapism

    Beneranda S. Ford-Glanton


    Full Text Available Penile gangrene is a rare but unfortunate complication of surgical intervention and priapism shunts. The literature regarding penile gangrene following surgical correction of priapism is sparse, the majority of which dates back to thirty to forty years. Here, we present the case of a 60-year-old man who presented with priapism that required operative management with a modified Al-Ghorab shunt and eventually suffered from complete necrosis of the penis with abscess formation in both corpora cavernosa.

  15. Incarceration of umbilical hernia after radiological insertion of a Denver peritoneovenous shunt.

    Ohta, Kengo; Shimohira, Masashi; Hashizume, Takuya; Kawai, Tatsuya; Kurosaka, Kenichiro; Suzuki, Kazushi; Watanabe, Kenichi; Shibamoto, Yuta


    We report a rare complication of incarceration of an umbilical hernia after Denver peritoneovenous shunt placement. A 50-year-old man presented with refractory ascites from liver cirrhosis. He also had an umbilical hernia. Because the ascites became uncontrollable, Denver peritoneovenous shunting was performed. The operation was successful and the ascites decreased. Ten days later, however, incarceration of the umbilical hernia occurred. A surgical repair was performed, but he died 2 days later. The cause of death was considered to be sepsis.

  16. New controllability criteria for 3-phase 4-wire inverters applied to shunt active power filters

    Perales Esteve, Manuel Ángel; Sánchez Segura, Juan Antonio; Torre, A. (Alberto) de la; Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo; Terrón, L.


    In shunt active filter applications, the 3-phase 4-wire topology is frequently used when dealing with unbalanced loads containing zero sequence components. A new design criteria for this topology is presented, based on the well-known existing method for the 3-phase 3-wire system. Simulation and experimental results confirms the validity of this new criteria, providing an easy method for the design of the reactive elements involved in a shunt active filter.


    汪余勤; 汪保灿; 顾胜利; 范建高


    We presented a case of chronic recurrent hepatic encephalopathy occurring in a liver cirrhosis patient (Child Pugh A) with a large gastrorenal shunt and a review of the literature focusing on diagnosis and management. Computed tomography (CT) demonstrated an atrophic liver, splenomegaly, varices at the gastric fundic and the splenic hilum, and a highly tortuous shunt vessel between the gastric fundic varices and the left renal vein. Ultrasonography revealed the portal vein diameter was 0.8 cm; and portal ve...

  18. DSA by means of fine-needle puncture for excluding vascular complications in haemodialysis shunts

    Alart, I.P.; Merk, J.; Eichner, H.


    The article on hand presents the experience gained with examinations of Cimino haemodialysis shunts using digital substraction angiography (DSA). Angiographic results after arterial and venous fine-needle puncture show - particularly in arterial DSA - the advantage of excellent contrasting of the afferent arterial vessel, of the arterio-venous anastomosis and of the venous return while allowing safe diagnosis. This examination procedure is low in complications for the patient, is suitable for outpatients and has numerous advantages over transvenous shunt DSA.

  19. Superconducting FCL using a combined inducted magnetic field trigger and shunt coil

    Tekletsadik, Kasegn D.


    A single trigger/shunt coil is utilized for combined induced magnetic field triggering and shunt impedance. The single coil connected in parallel with the high temperature superconducting element, is designed to generate a circulating current in the parallel circuit during normal operation to aid triggering the high temperature superconducting element to quench in the event of a fault. The circulating current is generated by an induced voltage in the coil, when the system current flows through the high temperature superconducting element.

  20. Utility of susceptibility-weighted imaging and arterial spin perfusion imaging in pediatric brain arteriovenous shunting

    Nabavizadeh, Seyed Ali; Edgar, J.C.; Vossough, Arastoo [University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)


    The objectives of the study are to investigate the application of susceptibility-weighted imaging (SWI) and arterial spin labeling (ASL) imaging in the assessment of shunting and the draining veins in pediatric patients with arteriovenous shunting and compare the utility of SWI and ASL with conventional MR and digital subtraction angiography (DSA). This study is a retrospective study of 19 pediatric patients with arteriovenous shunting on brain MRI who were also evaluated with DSA. We assessed the ability of conventional MRI sequences, susceptibility magnitude images, phase-filtered SWI images, and pulsed ASL images in the detection of arteriovenous (AV) shunting, number of draining veins and drainage pathways in comparison to DSA. The mean number of detected draining veins on DSA (3.63) was significantly higher compared to SWI phase-filtered image (mean = 2.72), susceptibility magnitude image (mean = 2.92), ASL (mean = 1.76) and conventional MRI (2.47) (p < 0.05). Pairwise comparison of DSA difference scores (i.e., difference between MR modalities in the number of missed draining veins) revealed no difference between the MR modalities (p > 0.05). ASL was the only method that correctly identified superficial and deep venous drainage in all patients. Regarding detection of shunting, ASL, SWI phase-filtered, and magnitude images demonstrated shunting in 100, 83, and 84 % of patients, respectively. SWI depicts a higher number of draining vein compared to conventional MR pulse sequences. ASL is a sensitive approach in showing 100 % sensitivity in the detection of AV shunting and in the diagnosis of the pattern of venous drainage. The present findings suggest the added utility of both SWI and ASL in the assessment of AV shunting. (orig.)

  1. DNA Damage-Induced HSPC Malfunction Depends on ROS Accumulation Downstream of IFN-1 Signaling and Bid Mobilization.

    Tasdogan, Alpaslan; Kumar, Suresh; Allies, Gabriele; Bausinger, Julia; Beckel, Franziska; Hofemeister, Helmut; Mulaw, Medhanie; Madan, Vikas; Scharfetter-Kochanek, Karin; Feuring-Buske, Michaela; Doehner, Konstanze; Speit, Günter; Stewart, A Francis; Fehling, Hans Joerg


    Mouse mutants with an impaired DNA damage response frequently exhibit a set of remarkably similar defects in the HSPC compartment that are of largely unknown molecular basis. Using Mixed-Lineage-Leukemia-5 (Mll5)-deficient mice as prototypical examples, we have identified a mechanistic pathway linking DNA damage and HSPC malfunction. We show that Mll5 deficiency results in accumulation of DNA damage and reactive oxygen species (ROS) in HSPCs. Reduction of ROS efficiently reverses hematopoietic defects, establishing ROS as a major cause of impaired HSPC function. The Ink4a/Arf locus also contributes to HSPC phenotypes, at least in part via promotion of ROS. Strikingly, toxic ROS levels in Mll5(-/-) mice are critically dependent on type 1 interferon (IFN-1) signaling, which triggers mitochondrial accumulation of full-length Bid. Genetic inactivation of Bid diminishes ROS levels and reverses HSPC defects in Mll5(-/-) mice. Overall, therefore, our findings highlight an unexpected IFN-1 > Bid > ROS pathway underlying DNA damage-associated HSPC malfunction.

  2. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol


    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results.

  3. Effect of rapamycin on hepatic osteodystrophy in rats with portasystemic shunting

    Schalk W van der Merwe; Del Kahn; Enid G Shephard; Maritha J Kotze; Nico P de Villiers; Stephen Hough; Maria M Conradie; Robert Bond; Brenda J Olivier; Elongo Fritz; Martin Nieuwoudt; Rhena Delport; Tomas Slavik; Gert Engelbrecht


    AIM: To study if T-cell activation related to portasystemic shunting causes osteodast-mediated bone loss through RANKL-dependent pathways. We also investigated if T-cell inhibition using rapamycin would protect against bone loss in rats.METHODS: Portasystemic shunting was performed in male Sprague-Dawley rats and rapamycin 0.1 mg/kg was administered for 15 wk by gavage. Rats received powderized chow and supplemental feeds to prevent the effects of malnutrition on bone composition. Weight gain and growth was restored after surgery in shunted animals. At termination, biochemical parameters of bone turnover and quantitative bone histology were assessed. Markers of T-cell activation, inflammatory cytokine production, and RANKL-dependent pathways were measured. In addition, the roles of IGF-1 and hypogonadism were investigated.RESULTS: Portasystemic shunting caused low turnover osteoporosis that was RANKL independent. Bone resorbing cytokine levels, including IL-1, IL-6 and TNFα,were not increased in serum and TNFα and RANKL expression were not upregulated in PBMC. Portasystemic shunting increased the circulating CD8+ T-cell population. Rapamycin decreased the circulating CD8+T-cell population, increased CD8+ CD25+ T-regulatory cell population and improved all parameters of bone turnover.CONCLUSION: Osteoporosis caused by portasystemic shunting may be partially ameliorated by rapamycin in the rat model of hepatic osteodystrophy.

  4. Bucket and straw technique to facilitate passage of a ventriculoperitoneal shunt through the distal tunneling sheath.

    Downes, Angela E; Vandergrift, William A; Beckman, Joshua M; Truong, Devon; Tuite, Gerald F


    Placement of a ventriculoperitoneal shunt (VPS) is a procedure comprising many small steps. Difficulties and delays can arise when passing the distal shunt tubing down the distal tunneling sheath during surgery. The authors of this report describe a simple technique for quickly passing the distal catheter of a VPS through the tunneler sheath, whereby the sheath is used as a fluid tube to allow the distal catheter to be drawn through the fluid tube under suction pressure. The plastic sheath that surrounds the shunt tunneler device is used as a fluid tube, or "straw," with the proximal aperture submerged into a bucket of sterile irrigation liquid containing the distal catheter. Suction pressure is placed against the distal aperture of the tunneler, and the shunt catheter is quickly drawn through the sheath. No special equipment is required. In time trials, the bucket and straw technique took an average of 0.43 seconds, whereas traditional passage methods took 32.3 seconds. The "bucket and straw" method for passing distal shunt tubing through the tunneler sheath is a technique that increases surgical efficiency and reduces manual contact with shunt hardware.

  5. Syringomyelia as a presenting feature of shunt dysfunction: Implications for the pathogenesis of syringomyelia

    Natarajan Muthukumar


    Full Text Available The pathogenesis of syringomyelia continues to be an enigma. The patency of the central canal and its role in the pathogenesis of communicating syringomyelia continues to elicit controversy. The case reported here provides an opportunity to retest some of the hypotheses of syringomyelia. A 33 year old female presented with sensory disturbances over the left upper extremity and trunk and was diagnosed to have panventriculomegaly with communicating syringomyelia. She was initially treated with ventriculoperitoneal shunting. As there was no change in her neurological status following shunt, this was followed by foramen magnum decompression with excision of an arachnoid veil covering the fourth ventricular outlet. She had clinical and radiological improvement after foramen magnum decompression. Five months later she had reappearance of the symptoms of syringomyelia and was found to have shunt dysfunction and holocord syrinx. She improved following shunt revision. This case is being reported to highlight the following points: 1. In patients with communicating syringomyelia and hydrocephalus, shunt dysfunction can present with symptoms of syringomyelia without the classical clinical features of shunt dysfunction, 2. In patients with communicating syringomyelia, the central canal of the spinal cord acts as an "exhaust valve" for the ventricular system, and, 3. studies about the patency of the central canal are reviewed in the context of this case and the role of the central canal in the pathogenesis of communicating syringomyelia is reviewed.

  6. Gender-dependent reduction of spontaneous motor activity and growth in rats subjected to portacaval shunt.

    Conjeevaram, H S; Mullen, K D; May, E J; McCullough, A J


    Alterations in behavior are frequently described in rats subjected to portacaval shunt. Previous work has reported reduced spontaneous motor activity in various settings (nighttime, red light, decreased illumination) in this animal model. We investigated this phenomenon in rats of both genders subjected to portacaval shunt to determine whether our previously observed divergent growth patterns (males reduced, females unchanged) had any impact on the alterations in spontaneous motor activity in this model. Dietary intake, growth, motor activity and serum ammonia and amino acid concentrations were measured, in addition to final liver and spleen weights, in each animal after 3 to 4 wk of observation. Our results reconfirm the differential impact of portacaval shunt on growth in male (35% reduction p < 0.01) but not female rats (5% reduction, NS) compared with their respective-gender sham-operated controls. In addition, spontaneous motor activity was significantly reduced in male (congruent to 50%, p = 0.01) but not female rats subjected to portacaval shunt. The reduction of activity in male rats subjected to portacaval shunt did not correlate with any of the measured biochemical data or calculated nutritional/growth parameters. Thus we observed gender-dependent reduction in spontaneous motor activity after portacaval shunt in the rat. The mechanism for this phenomenon is unknown, but it is easily investigated with this reproducible model.

  7. Shunt for bypass graft of the cavernous carotid artery: an anatomical and technical study.

    al-Mefty, O; Khalil, N; Elwany, M N; Smith, R R


    During direct surgery of neoplastic and vascular lesions of the cavernous sinus, the intracavernous carotid artery may be injured beyond repair, or its total isolation may be necessary for surgical management of these lesions. The newly developed procedure of a saphenous vein graft bypass of the cavernous carotid artery allows re-establishment of carotid circulation. Patients with poor collateral circulation are at high risk for ischemic complications induced by the prolonged temporary occlusion required to perform the bypass graft. Optimal management of these patients is to perform the venous bypass graft for permanent vascularization while maintaining carotid cerebral circulation through an intraoperative shunt. We studied this procedure in cadavers, and three shunt types were evaluated: the external intrapetrous-supraclinoid shunt (Type A), the internal intrapetrous-supraclinoid shunt (Type B), and the neck internal carotid-supraclinoid shunt (Type C). Anatomical landmarks, techniques, distances, caliber, and materials used are presented. The rationale and candidates for such a procedure are discussed. The specifications of an optimal balloon shunt are presented, and the three procedures are compared.

  8. Transjugular intrahepatic portosystemic shunt in children; Der transjugulaere intrahepatische portosystemische Shunt bei Kindern. Erste klinische Erfahrungen und Literaturuebersicht

    Huppert, P.E.; Brambs, H.J.; Schott, U.; Pereira, P.; Duda, S.H.; Claussen, C.D. [Tuebingen Univ. (Germany). Abt. fuer Radiologische Diagnostik; Astfalk, W.; Schweizer, P. [Tuebingen Univ. (Germany). Abt. Kinderchirurgie; Dopfer, R.E. [Tuebingen Univ. (Germany). Abt. Kinderheilkunde I


    Purpose: To present special methodical and clinical findings of transjugular intrahepatic portosystemic shunts (TIPSS) in children and to discuss potential indications. Patients and Methods: Between 1993 and 1996, 6 children aged 2-13 years were treated by TIPSS-insertion. In four cases, the underlying disease was extrahepatic biliary atresia (EHBA) and in two cases liver fibrosis secondary to treatment of neoplasms during early childhood. Indications for TIPSS insertion were variceal bleeding resistant to other treatment modalities in three patients, hypersplenism in one patient and both bleeding and hypersplenism in two. Portal vein punctures were performed using 16-gauge needles, because 19-gauge fine-needles showed insufficient stiffness. The mean follow-up was 24.5 months. Results: Shunt insertion succeeded in all children with a mean procedure time of 5.2 hours. Periportal fibrosis associated with EHBA, atypical course of hepatic veins and small diameters and distances of vessels were conditions making the procedure difficult. Bleeding ceased in all patients, peripheral platelet counts rose by a mean value of 58%. Procedure-related complications were minor extrahepatic bleeding in one child and temporary haemolysis in another child. Restenoses resulted in three patients and were treated successfully by means of transjugular interventions. 5 children remain free of symptoms to this day, one child underwent successful orthotopic liver transplantation 8 months after TIPSS. Conclusions: TIPSS insertion is technically more difficult in children and has to consider child growth and possible subsequent liver transplantation. Potential indications are recurrent variceal bleeding, also of intestinal origin, resistant to standard tretment and clinically significant hypersplenism. (orig.) [Deutsch] Ziel: Darstellung methodischer und klinischer Besonderheiten sowie potentieller Indikationen des transjugulaeren intrahepatischen portosystemischen Shunts (TIPSS) bei Kindern

  9. Oculo-peritoneal shunt: draining aqueous humor to the peritoneum.

    Maldonado-Junyent, Ana; Maldonado-Bas, Arturo; Gonzalez, Andrea; Pueyrredón, Francisco; Maldonado-Junyent, María; Maldonado-Junyent, Arturo; Rodriguez, Diego; Bulacio, Mariano


    In 2010, there were estimated to be approximately 60.5 million people with glaucoma. This number is expected to increase to 79.6 million by 2020. In 2010, there were 8.4 million people with bilateral blindness caused by glaucoma, and this number is expected in increase to 11.2 million by 2020. Filtering implants are special devices that have been developed to reduce intraocular pressure in patients with refractory glaucoma. The success rate of these implants is relatively low, and they continue to fail over time. To avoid failure caused by the formation of scar tissue around the implants, attempts have been made to drain the aqueous humor to various sites, including the venous system, lacrimal sac, sinuses, and conjunctival fornix. Recently, a system to shunt aqueous humor from the anterior chamber to the peritoneum has been developed. The surgical technique involved in this system is a modification of the technique currently used by neurosurgeons for the treatment of hydrocephalus. We present the first case operated using this technique.

  10. Ventriculoperitoneal shunt for hydrocephalus caused by central nervous system metastasis.

    Lee, Seung Hoon; Kong, Doo Sik; Seol, Ho Joon; Nam, Do-Hyun; Lee, Jung-Il


    The development of better diagnostic tools and therapeutic modalities has increased the incidence of central nervous system (CNS) metastasis in malignant tumor patients. Hydrocephalus can result from CNS metastasis and frustrate cancer treatment. The authors sought to investigate the outcomes and the roles of ventriculoperitoneal shunts (VPS) in patients with CNS metastasis. The medical records of 50 consecutive patients who underwent VPS for hydrocephalus related to CNS metastasis were analyzed retrospectively. Data included features of primary malignancies, CNS involvement, clinical course and surgical outcome. Median patient age was 55.0 years (range 25-77), and 30 female and 20 male patients were included in the study. At the time of VPS, 10 patients had parenchymal metastases only and 40 patients had leptomeningeal seeding (LMS). Symptom improvement was observed postoperatively in 40 patients (80%), mean Karnofsky performance status (KPS) scale change was from 37.8 to 46.0, and median survival from VPS was 3.0 months (2 days to 54 months). A ventricular opening pressure of >30 cmH(2)O (HR 6.44, 95% CI 1.26-32.9, P = 0.02) and further cancer treatment after VPS (HR 0.17, 95% CI 0.07-0.42, P Hydrocephalus in CNS metastasis requiring VPS is commonly associated with LMS. VPS is an effective palliative measure and an adequate cancer treatment after VPS may provide the best means of improving survival.

  11. Geometric Studies of Shunt and Lead Orientation in EEC Devices

    Werner, F. M.; Solin, S. A.


    Electric field sensors are ubiquitous in modern technology, from field effect transistors (FETs) in circuit boards to point-of-care testing (POCT) devices used in detecting the presence of specific protein markers in blood. The transport properties of these devices are limited by two general categories: intrinsic material properties and extrinsic geometric effects. Devices with a maximum electric field resolution of 3.05V/cm were previously reported. The metal semiconductor hybrid (MSH) devices are constructed by forming a Schottky interface between a mesa of nGaAs and Ti, while four ohmic leads surround the perimeter of the mesa and are used for four point resistance measurements. These devices exhibit extraordinary electroconductance (EEC) and make it possible to correlate measured four point resistance to changes in the local electric field. While maximizing the EEC response by optimizing the intrinsic material properties has been theoretically investigated, we present a phenomenological study of the impact of lead orientation and shunt geometry in the sensing capabilities of these devices. S.A.S. is a co-founder of and has a financial interest in PixelEXX, a start-up company whose mission is to market imaging arrays.

  12. Radiation doses to children with shunt-treated hydrocephalus

    Holmedal, Lise J. [Helse Fonna, Department of Radiology, Stord Hospital, Stord (Norway); Friberg, Eva G.; Boerretzen, Ingelin; Olerud, Hilde [The Norwegian Radiation Protection Authority, Oesteraas (Norway); Laegreid, Liv [Haukeland University Hospital, Department of Paediatrics, Bergen (Norway); Rosendahl, Karen [University of Bergen, Department of Surgical Sciences, Radiology Section, Bergen (Norway); Great Ormond Street Hospital for Children, Department of Diagnostic Radiology, London (United Kingdom)


    Children with shunt-treated hydrocephalus are still followed routinely with frequent head CT scans. To estimate the effective dose, brain and lens doses from these examinations during childhood, and to assess dose variation per examination. All children born between 1983 and 1995 and treated for hydrocephalus between 1983 and 2002 were included. We retrospectively registered the number of examinations and the applied scan parameters. The effective dose was calculated using mean conversion factors from the CT dose index measured free in air, while doses to the lens and brain were estimated using tabulated CT dose index values measured in a head phantom. A total of 687 CT examinations were performed in 67 children. The mean effective dose, lens dose and brain dose to children over 6 months of age were 1.2 mSv, 52 mGy and 33 mGy, respectively, and the corresponding doses to younger children were 3.2 mSv, 60 mGy and 48 mGy. The effective dose per CT examination varied by a factor of 64. None of the children was exposed to doses known to cause deterministic effects. However, since the threshold for radiation-induced damage is not known with certainty, alternative modalities such as US and MRI should be used whenever possible. (orig.)

  13. Transjugular intrahepatic portosystemic shunt in liver transplant recipients

    Armin Finkenstedt; Ivo W Graziadei; Karin Nachbaur; Werner Jaschke; Walter Mark; Raimund Margreiter; Wolfgang Vogel


    AIM: To evaluate the efficacy of transjugular intrahepatic portosystemic shunts (TIPSs) after liver transplantation (LT).METHODS: Between November 1996 and December 2005, 10 patients with severe recurrent hepatitis C virus infection ( n = 4), ductopenic rejection ( n = 5) or portal vein thrombosis ( n = 1) were included in this analysis. Eleven TIPSs (one patient underwent two TIPS procedures) were placed for management of therapy-refractory ascites ( n = 7), hydrothorax ( n = 2)or bleeding from colonic varices ( n = 1). The median time interval between LT and TIPS placement was 15(4-158) mo.RESULTS: TIPS placement was successful in all patients. The mean portosystemic pressure gradient was reduced from 12.5 to 8.7 mmHg. Complete and partial remission could be achieved in 43% and 29%of patients with ascites. Both patients with hydrothorax did not respond to TIPS. No recurrent bleeding was seen in the patient with colonic varices. Nine of 10patients died during the study period. Only one of two patients, who underwent retransplantation after the TIPS procedure, survived. The median survival period after TIPS placement was 3.3 (range 0.4-20) mo. The majority of patients died from sepsis with multiorgan failure.

  14. Operative timing and patient survival following distal splenorenal shunt.

    Pomerantz, R A; Eckhauser, F E; Knol, J A; Guirre, K; Raper, S E; Turcotte, J G


    The importance of "operative timing" in cirrhotic patients with variceal hemorrhage is often underemphasized. To evaluate the effects of immediate versus delayed selective portasystemic decompression on hepatic function, operative mortality, and long-term patient survival, we reviewed the records of 77 patients who underwent distal splenorenal shunts (DSRS) over a 14-year period. A hepatic risk status score was calculated at the time of the index bleed (HRS1) or presentation and again just prior to operation (HRS2). Variables analyzed included age, sex, prior bleeding episodes, time from index bleed to operation, transfusion requirements, and etiology of cirrhosis. Operative mortality rates for immediate versus delayed DSRS were 46.2 per cent and 17 per cent, respectively. HRS improved significantly in elective DSRS patients from 1.46 to 1.30. Predictors of HRS2 included HRS1 and time in days from the index bleed to operation. The most important predictor of early survival for all patients after elective DSRS was the HRS2; however, for patients who underwent elective DSRS and survived, HRS1 was a better predictor of length of survival than HRS2. No other variable analyzed accurately predicted survival. We conclude that HRS can be expected to improve with supportive inhospital therapy; improved HRS at the time of operation is associated with decreased operative mortality; and the extent of liver disease as determined by HRS1 appears to be the chief determinant of long-term patient survival.

  15. Vision Loss and Recovery after Baerveldt Aqueous Tube Shunt Implantation

    Kim, Esther Lee; Tran, Jeffrey; Töteberg-Harms, Marc; Chahal, Jasdeep; Rhee, Douglas


    This study aims to determine the course of vision loss after Baerveldt aqueous tube shunt placement and identify risk factors associated with unexplained severe long-term vision loss, or snuff-out. We retrospectively reviewed 247 eyes of 222 patients who underwent Baerveldt implantations at one of two academic institutions. Postoperative vision loss at 6 months following surgery was categorized as mild-to-moderate versus severe and long-term versus transient. Long-term vision loss, defined as 3 or more lines of Snellen visual acuity (VA) loss compared with preoperative VA, occurred in 63 of 247 eyes (25.5%), and 39 had mild-to-moderate and 24 had severe loss. Of these 63 eyes, 18 had no identifiable cause of vision loss. On multivariate analysis, poorer Snellen VA on postoperative day 1 (POD1) was found to be a significant risk factor for long-term vision loss (p = 0.005). In addition, the negative change in preoperative versus POD1 Snellen VA (p = 0.021) and the presence of split fixation involving the inferonasal quadrant on preoperative Humphrey visual field (p = 0.044) were significant risk factors for snuff-out. Transient vision loss occurred in 76 of 242 eyes (30.8%). In conclusion, vision loss is not uncommon after Baerveldt surgery, with snuff-out occurring in 2.4% of cases in this study.

  16. Oculo-peritoneal shunt: draining aqueous humor to the peritoneum

    Ana Maldonado-Junyent


    Full Text Available In 2010, there were estimated to be approximately 60.5 million people with glaucoma. This number is expected to increase to 79.6 million by 2020. In 2010, there were 8.4 million people with bilateral blindness caused by glaucoma, and this number is expected in increase to 11.2 million by 2020. Filtering implants are special devices that have been developed to reduce intraocular pressure in patients with refractory glaucoma. The success rate of these implants is relatively low, and they continue to fail over time. To avoid failure caused by the formation of scar tissue around the implants, attempts have been made to drain the aqueous humor to various sites, including the venous system, lacrimal sac, sinuses, and conjunctival fornix. Recently, a system to shunt aqueous humor from the anterior chamber to the peritoneum has been developed. The surgical technique involved in this system is a modification of the technique currently used by neurosurgeons for the treatment of hydrocephalus. We present the first case operated using this technique.

  17. Battery Equalization Control Based on the Shunt Transistor Method

    Gallardo-Lozano Javier


    Full Text Available Electric Vehicle (EV researches are currently becoming of special importance and the EV battery system is particularly relevant in the EV design. In these applications, series connected batteries are necessary since a single battery cannot achieve the voltage requirements. Internal and external sources lead the batteries string to become unbalanced, which is an important factor to be taken into account, as premature cells degradation, safety hazards, and reduced capacity will occur for unbalanced systems. The different balancing methods are presented and compared in this paper, and finally the switch capacitor and the double-tiered switching capacitor are considered the best option. However, their speed depends on the voltage difference between the batteries in the string, and when their voltage difference is low, the equalization speed decreases significantly, leading the battery pack to be unbalanced for longer. A novel equalization method is presented, that improves the aforementioned methods performance by applying a new control to a shunt transistor method. Low cost, size, and complexity, together with higher speed and efficiency are obtained. A prototype has been built, and experimental results are presented.

  18. Acute pancreatitis

    ... its blood vessels. This problem is called acute pancreatitis. Acute pancreatitis affects men more often than women. Certain ... pancreatitis; Pancreas - inflammation Images Digestive system Endocrine glands Pancreatitis, acute - CT scan Pancreatitis - series References Forsmark CE. Pancreatitis. ...

  19. Cystitis - acute

    Uncomplicated urinary tract infection; UTI - acute cystitis; Acute bladder infection; Acute bacterial cystitis ... cause. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  20. Adaptive right ventricular performance in response to acutely increased afterload in a lamb model of congenital heart disease: evidence for enhanced Anrep effect.

    Johnson, Rebecca C; Datar, Sanjeev A; Oishi, Peter E; Bennett, Stephen; Maki, Jun; Sun, Christine; Johengen, Michael; He, Youping; Raff, Gary W; Redington, Andrew N; Fineman, Jeffrey R


    Patients with pulmonary hypertension associated with congenital heart disease survive longer with preserved right ventricular (RV) function compared with those with primary pulmonary hypertension. The purpose of this study was to test the hypothesis that superior RV performance can be demonstrated, at baseline and when challenged with increased RV afterload, in lambs with chronic left-to-right cardiac shunts compared with control lambs. A shunt was placed between the pulmonary artery and the aorta in fetal lambs (shunt). RV pressure-volume loops were obtained 4 wk after delivery in shunt and control lambs, before and after increased afterload was applied using pulmonary artery banding (PAB). Baseline stroke volume (8.7 ± 1.8 vs. 15.8 ± 2.7 ml, P = 0.04) and cardiac index (73.0 ± 4.0 vs. 159.2 ± 25.1 ml·min(-1)·kg(-1), P = 0.02) were greater in shunts. After PAB, there was no difference in the change in cardiac index (relative to baseline) between groups; however, heart rate (HR) was greater in controls (168 ± 7.3 vs. 138 ± 6.6 beats/min, P = 0.01), and end-systolic elastance (Ees) was greater in shunts (2.63 vs. 1.31 × baseline, P = 0.02). Control lambs showed decreased mechanical efficiency (71% baseline) compared with shunts. With acute afterload challenge, both controls and shunts maintained cardiac output; however, this was via maladaptive responses in controls, while shunts maintained mechanical efficiency and increased contractility via a proposed enhanced Anrep effect-the second, slow inotropic response in the biphasic ventricular response to increased afterload, a novel finding in the RV. The mechanisms related to these physiological differences may have important therapeutic implications.

  1. Ventriculo-bipleural shunt as last resort in a 4-year-old child in whom a VP and VA shunt failed.

    Ratliff, Miriam; Unterberg, Andreas; Bächli, Heidi


    The authors present the unusual case of a 4-year-old boy who had a complex history of posthemorrhagic hydrocephalus and who underwent more than 40 surgeries related to this condition. In the course of trying to treat his condition, ventriculoperitoneal, ventriculoatrial, and ventriculopleural shunts were inserted and failed. The child presented with a dysfunction of his shunt system. A ventriculopleural shunt was inserted, but within days the patient developed dyspnea as a clinical symptom of pleural effusion that required repeated thoracentesis. A bipleural drainage system was inserted, and no relevant pleural effusions developed during the follow-up period. Although the authors' experience is based on a single case, they do suggest bipleural drainage in patients with clinically relevant pleural effusions when the more common alternatives are not a good choice. Bipleural drainage might particularly be an option in children, who are prone to pleural effusion because of the smaller absorbing pleural surface. The authors reviewed the English-language literature on PubMed dating back to 1952. To their knowledge, this is the only published case in which a patient was treated with a ventriculo-bipleural shunt.

  2. Cerebral Blood Flow Changes after Shunt in Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage: Analysis by statistical Parametric Mapping

    Hyun, I. Y.; Choi, W. S.; Pak, H. S. [College of Medicine, Univ. of Inhwa, Incheon (Korea, Republic of)


    The purpose of this study was to evaluate the changes of regional cerebral blood flow (rCBF) after shunt operation in patients with hydrocephalus after aneurysmal subarachnoid hemorrhage ba statistical parametric mapping (SPM). Seven patients (4 male, mean age 54 years) with hydrocephalus after aneurysmal subarachnoid hemorrhage underwent a shunt operation. Tc-99m HMPAO SPECT was performed within I week before, and 2 weeks after the shunt operation. All of the SPECT images were spatially transformed to standard space, smoothed, and globally normalized. After spatial and count normalization, rCBF of pre- and post- shunting Tc- 99m HMPAO SPECT was estimated at every voxel using t statistics. The voxels with a P value of less than 0.001 were considered to be significantly different. The shunt operation was effective in all patients. Pre-shunting Tc-99m HMPAO SPECT showed hypoperfusion, predominantly in the periventricular area. After shunt operation, periventricular low perfusion was disappeared. The results of this study show that periventricular CBF is impaired in hydrocephalus after aneurysmal subarachnoid hemorrhage. Significant increase of periventricular CBF after shunt operation suggests the evaluation of periventricular CBF by SPM might be of value for the prediction of shunt effectiveness in hydrocephalus.

  3. Conversion of Low-Flow Priapism to High-Flow State Using T-Shunt with Tunneling

    Tadros, Nicholas N.; Hedges, Jason C.


    Introduction. The three types of priapism are stuttering, arterial (high-flow, nonischemic), and venoocclusive (low-flow, ischemic). These are usually distinct entities and rarely occur in the same patient. T-shunts and other distal shunts are frequently combined with tunneling, but a seldom recognized potential complication is conversion to a high-flow state. Case Presentation. We describe 2 cases of men who presented with low-flow priapism episodes that were treated using T-shunts with tunneling that resulted with both men having recurrent erections shortly after surgery that were found to be consistent with high-flow states. Case 1 was a 33-year-old male with sickle cell anemia and case 2 was a 24-year-old male with idiopathic thrombocytopenic purpura. In both cases the men were observed over several weeks and both men returned to normal erectile function. Conclusions. Historically, proximal shunts were performed only in cases when distal shunts failed and carry a higher risk of serious complications. T-shunts and other distal shunts combined with tunneling are being used more frequently in place of proximal shunts. These cases illustrate how postoperative erections after T-shunts with tunneling can signify a conversion from low-flow to high-flow states and could potentially be misdiagnosed as an operative failure. PMID:28331646

  4. Spontaneous resolution of splenic infarcts after distal splenorenal shunt in children with extra hepatic portal venous obstruction: Our experience

    Arbinder Kumar


    Full Text Available Background: In cases of portal hypertension with splenic infarcts, splenectomy with proximal splenorenal shunt has been recommended. We are sharing our experience with distal splenorenal shunt in these cases contrary to the popular belief. Materials and Methods: Splenic infarcts were graded as mild, moderate and severe according to the pre-operative CT portogram. Mild, moderate and severe infarcts were defined as an infarct involving 50% area of the spleen, respectively. Mild and moderate infarcts were managed by spleen-preserving distal splenorenal shunt while those with extensive infarcts were subjected to splenectomy and proximal splenorenal shunt. Those with spleen-preserving shunts were closely followed in the post-operative period according to a uniform protocol. Clinical examination was regularly done to assess the size of the spleen and note the presence of pain, tenderness in the left intercostal space. An ultrasound Doppler was done after 7 days to assess shunt patency while CT portogram was repeated at 6 monthly intervals. Results: Fourteen cases with splenic infarcts formed the study group. Eight cases had mild infarcts, 3 had moderate infarcts and 3 had severe infarcts. Four underwent proximal splenorenal shunt, and 10 underwent warren′s shunt (8 with mild and 2 with moderate infarcts. In 9/10 (90%, spleen could eventually be retained. Spleen completely regressed in them and so did the infarct. Conclusions:Spleen-preserving distal splenorenal shunt can be considered as a viable option in the management of cases with mild and carefully selected moderate splenic infarcts.

  5. The clinical application and nursing experience of adjustable shunt valve in treatment for patients with normal pressure hydrocephalus

    YANG Li-rong


    Full Text Available Objective To introduce the application of adjustable shunt valve in treatment for patients with normal pressure hydrocephalus. Methods Twenty-four patients with normal pressure hydrocephalus implanted adjustable shunt valve underwent ventriculo-peritoneal shunt surgery and nursing care. Results After operation, cerebrospinal pressure was regulated for 0-6 (1.88 ± 1.52 times. Clinical symptoms were improved, especially in gait disturbance. Conclusion Treatment of normal pressure hydrocephalus with adjustable shunt valve can alleviate symptoms of hydrocephalus. It is especially suitable for patients with short course and secondary normal hydrocephalus patients.

  6. In vitro hydrodynamic properties of the Miethke proGAV hydrocephalus shunt

    Richards Hugh K


    Full Text Available Abstract Background Adjustable shunts are very popular in the management of hydrocephalus and are believed to help in minimizing the number of surgical revisions. The drawback with almost all constructions is that they may be accidentally readjusted in relatively weak magnetic fields (around 30–40 mTesla Materials and methods The ProGav Miethke shunt is composed of an adjustable ballon-spring valve unit and an integrated over-drainage compensating gravitational device (known as the shunt assistant. A mechanical 'brake' is intended to prevent changes to the valve's performance level in a strong magnetic field. We evaluated the performance and hydrodynamic properties of a sample of three valves in the UK Shunt Evaluation Laboratory. Results All the shunts showed good mechanical durability over the three-month period of testing, and good stability of hydrodynamic performance over a one-month period The pressure-flow performance curves, operating, opening and closing pressures fell within the limits specified by the manufacturer, and changed according to the programmed performance levels. The operating pressure increased when the shunt assistant was in the vertical position, as specified. The valve has a low hydrodynamic resistance (0.53 mm mmHg ml-1 min-1. External programming proved to be easy and reliable. Strong magnetic fields from a 3 Tesla MR scanner were not able to change the programming of the valve. Conclusion The ProGAV shunt is an adjustable, low resistance valve that is able to limit posture-related over-drainage. Unlike other adjustable valves, the ProGAV cannot be accidentally re-adjusted by external magnetic field such as a 3T MR scanner.

  7. The reversibility of reduced cortical vein compliance in normal-pressure hydrocephalus following shunt insertion

    Bateman, G.A. [Department of Medical Imaging, John Hunter Hospital, Locked Bag 1, Newcastle Region Mail Centre, Newcastle (Australia)


    Superficial cortical venous compression secondary to alterations in craniospinal compliance is implicated in the pathogenesis of normal pressure hydrocephalus (NPH). A reduction in the pulsation in the outflow of the cortical veins would be expected to occur following compression of these veins and this has been shown in NPH. If cortical vein compression is a causative factor in NPH, it would be expected that cortical vein compliance as measured by pulsatility would be significantly altered by a curative procedure i.e. shunt tube insertion. My purpose is to compare the blood flow pulsatility characteristics in a group of patients with NPH before and after shunt tube insertion. I initially studied 18 subjects without pathology with MRI flow quantification studies of the cerebral arteries and veins to define the range of normality. The main study involved 18 patients with idiopathic dementia and mild leukoaraiosis who served as controls and seven patients with NPH studied before and after shunt insertion. Arterial, superior sagittal and straight sinus pulsatility was not significantly different between the patients with idiopathic dementia and those NPH patients before or after shunting. Cortical vein pulsatility before shunting in the patients with NPH was 43% lower than in those with idiopathic dementia (P =0.006). Following shunting, cortical vein pulsatility increased by 186% (P =0.007). There is thus reduced compliance in cortical veins in NPH which is significantly increased in patients who respond to insertion of a shunt tube. These findings suggest that reversible elevation in cortical vein pressure and reversal of the normal absorption pathway for cerebrospinal fluid may be behind the pathophysiology of NPH. (orig.)

  8. Implementation of an artificial neuronal network to predict shunt necessity in carotid surgery.

    Aleksic, Marko; Luebke, Thomas; Heckenkamp, Joerg; Gawenda, Michael; Reichert, Viktor; Brunkwall, Jan


    In carotid surgery, it could be useful to know which patient will tolerate carotid cross-clamping in order to minimize the risks of perioperative strokes. In this clinical study, an artificial neuronal network (ANN) was applied and compared with conventional statistical methods to assess the value of various parameters to predict shunt necessity. Eight hundred and fifty patients undergoing carotid endarterectomy for a high-grade internal carotid artery stenosis under local anesthesia were analyzed regarding shunt necessity using a standard feed-forward, backpropagation ANN (NeuroSolutions); NeuroDimensions, Gainesville, FL) with three layers (one input layer, one hidden layer, one output layer). Among the input neurons, preoperative clinical (n = 9) and intraoperative hemodynamic (n = 3) parameters were examined separately. The accuracy of prediction was compared to the results of a regression analysis using the same variables. In 173 patients (20%) a shunt was used because hemispheric deficits or unconsciousness occurred during cross-clamping. With the ANN, not needing a shunt was predicted by preoperative and intraoperative parameters with an accuracy of 96% and 91%, respectively, where the regression analysis showed an accuracy of 98% and 96%, respectively. Those patients who needed a shunt were identified by preoperative parameters in 9% and by intraoperative parameters in 56% when the ANN was used. Regression analysis predicted shunt use correctly in 10% using preoperative parameters and 41% using intraoperative parameters. Intraoperative hemodynamic parameters are more suitable than preoperative parameters to indicate shunt necessity where the application of an ANN provides slightly better results compared to regression analysis. However, the overall accuracy is too low to renounce perioperative neuromonitoring methods like local anesthesia.

  9. Angiography-based C-arm CT for the assessment of extrahepatic shunting before radioembolization

    Heusner, Till Alexander; Hahn, S.; Forsting, M.; Antoch, G. [Inst. fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie, Universitaetsklinik Essen (Germany); Hamami, M.E.; Poeppel, T.; Bockisch, A. [Klinik fuer Nuklearmedizin, Universitaetsklinik Essen (Germany); Ertle, J.; Hilgard, P. [Klinik fuer Gastroenterologie, Universitaetsklinik Essen (Germany)


    Purpose: to retrospectively assess the accuracy of angiography-based C-arm CT for the detection of extrahepatic shunting before SIRT. Materials and methods: 30 patients (mean age: 64 {+-} 12 years) with hypervascularized hepatic tumors underwent hepatic angiography, coil embolization of gastrointestinal collaterals and 99mTc-macroaggregated albumin (MAA) SPECT/CT before SIRT. Before MAA injection via a microcatheter from the intended treatment position, an angiography and angiography-based C-arm CT (XperCT trademark, Philips Healthcare) were acquired. Angiographies and XperCT trademark were performed from 48 microcatheter positions followed by MAA injections and MAA-SPECT/CT. MAA-SPECT/CT served as the reference standard for determining the accuracy of hepatic arteriography and C-arm CT for the detection of extrahepatic shunting. Results: MAA-SPECT/CT revealed extrahepatic shunting in 5 patients (17%). Hepatic arteriography yielded a true negative in 22 (73%), a false negative in 5 (17%), and an unclear result in 3 patients (10%). C-arm CT yielded a true positive in 3 (10%), true negative in 24 (80%), false positive in 1 (3%), and false negative in 2 patients (7%). The specificity and the NPV of hepatic arteriography for the detection of extrahepatic shunting were 88% and 81%, respectively. For C-arm CT the sensitivity, specificity, PPV, NPV, and accuracy for the detection of extrahepatic shunting were 60%, 96%, 75%, 92%, and 90%, respectively. Conclusion: C-arm CT offers additional information to angiography when assessing SIRT patients for extrahepatic shunting. More accurate detection of extrahepatic shunting may optimize the workflow in SIRT preparations by avoiding unnecessary repeat angiographies. (orig.)

  10. Impact of cerebrospinal fluid shunting for idiopathic normal pressure hydrocephalus on the amyloid cascade.

    Masao Moriya

    Full Text Available The aim of this study was to determine whether the improvement of cerebrospinal fluid (CSF flow dynamics by CSF shunting, can suppress the oligomerization of amyloid β-peptide (Aβ, by measuring the levels of Alzheimer's disease (AD-related proteins in the CSF before and after lumboperitoneal shunting. Lumbar CSF from 32 patients with idiopathic normal pressure hydrocephalus (iNPH (samples were obtained before and 1 year after shunting, 15 patients with AD, and 12 normal controls was analyzed for AD-related proteins and APLP1-derived Aβ-like peptides (APL1β (a surrogate marker for Aβ. We found that before shunting, individuals with iNPH had significantly lower levels of soluble amyloid precursor proteins (sAPP and Aβ38 compared to patients with AD and normal controls. We divided the patients with iNPH into patients with favorable (improvement ≥ 1 on the modified Rankin Scale and unfavorable (no improvement on the modified Rankin Scale outcomes. Compared to the unfavorable outcome group, the favorable outcome group showed significant increases in Aβ38, 40, 42, and phosphorylated-tau levels after shunting. In contrast, there were no significant changes in the levels of APL1β25, 27, and 28 after shunting. After shunting, we observed positive correlations between sAPPα and sAPPβ, Aβ38 and 42, and APL1β25 and 28, with shifts from sAPPβ to sAPPα, from APL1β28 to 25, and from Aβ42 to 38 in all patients with iNPH. Our results suggest that Aβ production remained unchanged by the shunt procedure because the levels of sAPP and APL1β were unchanged. Moreover, the shift of Aβ from oligomer to monomer due to the shift of Aβ42 (easy to aggregate to Aβ38 (difficult to aggregate, and the improvement of interstitial-fluid flow, could lead to increased Aβ levels in the CSF. Our findings suggest that the shunting procedure can delay intracerebral deposition of Aβ in patients with iNPH.

  11. External lumbar drain: A pragmatic test for prediction of shunt outcomes in idiopathic normal pressure hydrocephalus

    Silky Chotai


    Full Text Available Background: The consensus on most reliable supplemental test to predict the shunt responsiveness in patients with idiopathic normal pressure hydrocephalus (iNPH is lacking. The aim of this study is to discuss the utility of external lumbar drain (ELD in evaluation of shunt responsiveness for iNPH patients. Methods: A retrospective review of 66 patients with iNPH was conducted. All patients underwent 4-day ELD trial. ELD-positive patients were offered ventriculoperitoneal shunt (VPS surgery. The primary outcome evaluation parameters were gait and mini mental status examination (MMSE assessment. The family and patient perception of improvement was accounted for in the outcome evaluation. Results: There were 38 male and 28 female with mean age of 74 years (range 45-88 years. ELD trial was positive in 86% (57/66 of patients. No major complications were encountered with the ELD trial. A total of 60 patients (57 ELD-positive, 3 ELD-negative underwent VPS insertion. The negative ELD trial (P = 0.006 was associated with poor outcomes following shunt insertion. The positive ELD trial predicted shunt responsiveness in 96% patients (P < 0.0001, OR = 96.2, CI = 11.6-795.3. A receiver operating characteristic (ROC curve analysis revealed that the ELD trial is reasonably accurate in differentiating shunt responder from non-responder in iNPH patients (area under curve = 0.8 ± 0.14, P = 0.02, CI = 0.52-1.0. The mean follow-up period was 12-months (range 0.3-3 years. The significant overall improvement after VPS was seen in 92% (55/60. The improvement was sustained in 76% of patients at mean 3-year follow-up. The number of comorbid conditions (P = 0.034, OR = 4.15, CI = 1.2-9.04, and a history of cerebrovascular accident (CVA (P = 0.035, OR = 4.4, CI = 1.9-14.6 were the predictors of poor outcome following shunt surgery. Conclusion: The positive ELD test predicted shunt responsiveness in 96% of patients. With adequate technique, maximal results with minimal

  12. Cerebral oxygenation and processed EEG response to clamping and shunting during carotid endarterectomy under general anesthesia.

    Perez, William; Dukatz, Christopher; El-Dalati, Sami; Duncan, James; Abdel-Rasoul, Mahmoud; Springer, Andrew; Go, Michael R; Dzwonczyk, Roger


    Clamping and shunting during carotid endarterectomy (CEA) surgery causes changes in cerebral blood flow. The purpose of this study was to assess and compare, side by side, the cerebral oxygenation (rSO2) and processed electroencephalogram (EEG) response bilaterally to carotid artery clamping and shunting in patients undergoing CEA under general anesthesia. With institutional approval and written informed consent, patients undergoing CEA under general anesthesia and routine carotid artery shunting were recorded bilaterally, simultaneously and continuously with an rSO2 and processed EEG monitor. The response of the monitors during carotid artery clamping and shunting were assessed and compared between monitors and bilaterally within each monitor. Sixty-nine patients were included in the study. At clamping the surgical-side and contralateral-side rSO2 dropped significantly below the baseline incision value (-17.6 and -9.4% respectively). After shunting, the contralateral-side rSO2 returned to baseline while the surgical-side rSO2 remained significantly below baseline (-9.0%) until the shunt was removed following surgery. At clamping the surgical-side and contralateral-side processed EEG also dropped below baseline (-19.9 and -20.6% respectively). However, following shunt activation, the processed EEG returned bilaterally to baseline. During the course of this research, we found the rSO2 monitor to be clinically more robust (4.4% failure rate) than the processed EEG monitor (20.0% failure rate). There was no correlation between the rSO2 or processed EEG changes that occurred immediately after clamping and the degree of surgical side stenosis measured pre-operatively. Both rSO2 and processed EEG respond to clamping and shunting during CEA. Cerebral oximetry discriminates between the surgical and contralateral side during surgery. The rSO2 monitor is more reliable in the real-world clinical setting. Future studies should focus on developing algorithms based on these

  13. Reduction of astrogliosis and microgliosis by cerebrospinal fluid shunting in experimental hydrocephalus

    Miller Janet M


    Full Text Available Abstract Background Reactive gliosis has the potential to alter biomechanical properties of the brain, impede neuronal regeneration and affect plasticity. Determining the onset and progression of reactive astrogliosis and microgliosis due to hydrocephalus is important for designing better clinical treatments. Methods Reactive astrogliosis and microgliosis were evaluated as the severity of hydrocephalus increased with age in hydrocephalic H-Tx rats and control littermates. Previous studies have suggested that gliosis may persist after short-term drainage (shunt treatment of the cerebrospinal fluid. Therefore shunts were placed in 15d hydrocephalic rats that were sacrificed after 6d (21d of age or after 21d (36d of age. Tissue was processed for Western blot procedures and immunohistochemistry, and probed for the astrocytic protein, Glial Fibrillary Acidic Protein (GFAP and for microglial protein, Isolectin B4 (ILB4. Results In the parietal cortex of untreated hydrocephalic animals, GFAP levels increased significantly at 5d and at 12d compared to age-matched control rats. There was a continued increase in GFAP levels over control at 21d and at 36d. Shunting prevented some of the increase in GFAP levels in the parietal cortex. In the occipital cortex of untreated hydrocephalic animals, there was a significant increase over control in levels of GFAP at 5d. This trend continued in the 12d animals, although not significantly. Significant increases in GFAP levels were present in 21d and in 36d animals. Shunting significantly reduced GFAP levels in the 36d shunted group. Quantitative grading of immuno-stained sections showed similar changes in GFAP stained astrocytes. Immuno-stained microglia were altered in shape in hydrocephalic animals. At 5d and 12d, they appeared to be developmentally delayed with a lack of processes. Older 21d and 36d hydrocephalic animals exhibited the characteristics of activated microglia, with thicker processes and enlarged

  14. Micro-fabricated shunt to mimic arachnoid granulations for the treatment of communicating hydrocephalus.

    Kralick, Francis; Oh, Jonghyun; Medina, Tim; Noh, Hongseok Moses


    Hydrocephalus is the abnormal accumulation of cerebrospinal fluid (CSF) within the confines of the skull that if left untreated results in significant morbidity and mortality. The treatment for hydrocephalus has remained essentially unchanged for over 50 years. It was a technological advance in materials that allowed John Holter, in conjunction with neurosurgeons Spitzer and Nulsen, to devise a valve and shunt system that diverted excess CSF from the ventricular space to the peritoneum. This ventriculo-peritoneal (VP) shunt is far from ideal, with problems associated with under/over shunting, mechanical mismatch, infection, high failure rates, disconnection and erosion. With the advances in the field of micro-fabrication and micro-machines we propose an innovative shunt system that would mimic the function of arachnoid granulations. This micro-fabricated shunting device, or micro-mechanical arachnoid granulation (MAG), consists of a multiplicity of micro-valves each 210 μm in diameter that each adhere to individual micro-needles. This work demonstrates the design and initial test results of the micro-valve with parameters for low cracking pressure, optimal flow rate, and reflux that would mimic the function of the native arachnoid granulations.

  15. Laboratory study on "intracranial hypotension" created by pumping the chamber of a hydrocephalus shunt

    Richards Hugh K


    Full Text Available Abstract Background It has been reported that pumping a shunt in situ may precipitate a proximal occlusion, and/or lead to ventricular over-drainage, particularly in the context of small ventricles. In the laboratory we measured the effect of pumping the pre-chamber of hydrocephalus shunts on intracranial hypotension. Materials and methods A simple physical model of the CSF space in a hydrocephalic patient was constructed with appropriate compliance, CSF production and circulation. This was used to test eleven different hydrocephalus shunts. The lowest pressure obtained, the number of pumps needed to reach this pressure, and the maximum pressure change with a single pump, were recorded. Results All models were able to produce negative pressures ranging from -11.5 mmHg (Orbis-Sigma valve to -233.1 mmHg (Sinu-Shunt. The number of pumps required reaching these levels ranged from 21 (PS Medical LP Reservoir to 315 (Codman Hakim-Programmable. The maximum pressure change per pump ranged from 0.39 mmHg (Orbis-Sigma valve to 23.1 (PS Medical LP Reservoir. Conclusion Patients, carers and professionals should be warned that 'pumping' a shunt's pre-chamber may cause a large change in intracranial pressure and predispose the patient to ventricular catheter obstruction or other complications.

  16. Decompensated porto-pulmonary hypertension in a cirrhotic patient with thrombosis of portocaval shunt


    We report a case of decompensated porto-pulmonary hypertension closely associated with the development of intra-portocaval shunt thrombosis. A woman with Laennec's cirrhosis was hospitalized because of severe dyspnea and edema. She underwent surgical portocaval anastomosis ten years ago. Imaging studies showed massive intra-shunt thrombosis, portal hypertension, ascites, pleuro-pericardial effusions and enlargement of right cardiac cavities. Cardiac catheterization allowed to rule out coronary and leftsided heart abnormalities and led to the diagnosis of pre-capillary pulmonary hypertension. Antithrombotic treatment with low molecular weight heparin was instituted. The management also included ACE inhibitors,spironolactone, low-salt diet and lactulose. The patient was discharged and three months later we observed the disappearance of edema, ascites and pleuropericardial effusions, a marked body weight reduction and improved dyspnea and liver function tests. A possible link between the development of intra-shunt thrombosis and clinical decompensation in our patient was hypothesized. In fact, it has been demonstrated that the increased portal pressure, caused by occlusion of portosystemic shunt, reduces renal plasma flow and increases systemic endothelin-1 concentration. In our patient the disappearance of edematous state and improved dyspnea observed after recanalization of the shunt strongly support this hypothesis.

  17. The C57BL/6J mouse exhibits sporadic congenital portosystemic shunts.

    Cristina Cudalbu

    Full Text Available C57BL/6 mice are the most widely used strain of laboratory mice. Using in vivo proton Magnetic Resonance Spectroscopy ((1H MRS, we have repeatedly observed an abnormal neurochemical profile in the brains of both wild-type and genetically modified mice derived from the C57BL/6J strain, consisting of a several fold increase in cerebral glutamine and two fold decrease in myo-inositol. This strikingly abnormal neurochemical "phenotype" resembles that observed in chronic liver disease or portosystemic shunting and appeared to be independent of transgene, origin or chow and was not associated with liver failure. As many as 25% of animals displayed the abnormal neurochemical profile, questioning the reliability of this model for neurobiology. We conducted an independent study to determine if this neurochemical profile was associated with portosystemic shunting. Our results showed that 100% of the mice with high brain glutamine displayed portosystemic shunting by concomitant portal angiography while all mice with normal brain glutamine did not. Since portosystemic shunting is known to cause alterations in gene expression in many organs including the brain, we conclude that portosystemic shunting may be the most significant problem associated with C57BL/6J inbreeding both for its effect on the central nervous system and for its systemic repercussions.

  18. Acute Respiratory Distress Syndrome in Obstetric Patients

    S. V. Galushka


    Full Text Available Objective: to define the specific features of the course of acute respiratory distress syndrome (ARDS in puer-peras with a complicated postpartum period. Subjects and methods. Sixty-seven puerperas with ARDS were examined. Group 1 included 27 puerperas with postpartum ARDS; Group 2 comprised 10 puerperas who had been treated in an intensive care and died; Group 3 consisted of nonobstetric patients with ARDS of various genesis (a control group. Results. In obstetric patients, the baseline oxygenation index was significantly lower than that in the control group. However, Group 1 patients showed a rapid increase in PaO2/FiO2 on days 3—4 of treatment. In the control group, the changes occurred later — on days 5—6. The baseline alveolar-arterial oxygen difference was significantly higher in the obstetric patients than that in the controls. In Group 1, AaDpO2 drastically decreased on days 3—4, which took place in parallel with an increase in the oxygenation index. At the beginning of the study, pulmonary shunting was high in the group of survivors, deceased, and controls. In Group 1, the shunting decreased on days 3—4 whereas in the control group this index normalized later — only by days 6—7. In Group 1, compliance remained lower throughout the observation, but on day 7 there was a significant difference in this index between the deceased, survivors, and controls. Conclusion. Thus, more severe baseline pulmonary gas exchange abnormalities are observed in obstetric patients than in general surgical and traumatological patients; the oxygenation index, alveolar-arterial oxygen difference, and pulmonary shunting index more rapidly change in patients with severe obstetric disease in its favorable course than in general surgical and traumatological patients; throughout the observation, thoracopulmonary compliance was less in obstetric patients than in the controls. Key words: acute respiratory distress syndrome, puerperium.

  19. Acute Bronchitis

    ... Smoking also slows down the healing process. Acute bronchitis treatment Most cases of acute bronchitis can be treated at home.Drink fluids, but ... bronchial tree. Your doctor will decide if this treatment is right for you. Living with acute bronchitis Most cases of acute bronchitis go away on ...

  20. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt: A Case Report and Literature Review.

    Ma, Li; Chen, Yi-Li; Yang, Shu-Xu; Wang, Yi-Rong


    The ventriculoperitoneal (VP) shunt is a routine procedure for cerebrospinal fluid (CSF) diversion, and is associated with many complications. A delayed hemorrhage after the VP shunt surgery, however, is quite rare. In this study, we report a case involving late-onset hemorrhage. The 67-year-old male patient with a history of head trauma and brain surgery underwent a VP shunt placement for hydrocephalus. The surgery course was uneventful and no bleeding was revealed in the first computed tomographic (CT) scan after the procedure. However, a massive intraparenchymal and intraventricular hemorrhage occurred 8 h following adjustment of the valve system on the 8th day after surgery.Erosion of the vasculature by catheter cannulation and a sudden reduction of CSF pressure after downregulation of the valve could be one of the possible causes of the intracerebral hemorrhage (ICH).

  1. Instantaneous Power Theory with Fourier and Optimal Predictive Controller Design for Shunt Active Power Filter

    Suksan Tiyarachakun


    Full Text Available This paper presents a novel harmonic identification algorithm of shunt active power filter for balanced and unbalanced three-phase systems based on the instantaneous power theory called instantaneous power theory with Fourier. Moreover, the optimal design of predictive current controller using an artificial intelligence technique called adaptive Tabu search is also proposed in the paper. These enhancements of the identification and current control parts are the aim of the good performance for shunt active power filter. The good results for harmonic mitigation using the proposed ideas in the paper are confirmed by the intensive simulation using SPS in SIMULINK. The simulation results show that the enhanced shunt active power filter can provide the minimum %THD (Total Harmonic Distortion of source currents and unity power factor after compensation. In addition, the %THD also follows the IEEE Std.519-1992.

  2. Low-frequency vibration isolation in sandwich plates by piezoelectric shunting arrays

    Chen, Shengbing; Wang, Gang; Song, Yubao


    Piezoelectric shunting arrays are proposed to isolate low-frequency vibrations transmitted in sandwich plates. The performance is characterized through application of finite element method. The numerical result shows that a complete band gap, whose width is about 20 Hz, is produced in the desired low-frequency ranges. The band gap is induced by local resonances of the shunting circuits, whose location is strongly related to the inductance, while the resistance can broaden the band gap to some extent. Vibration experiments are conducted on a 1200 × 1000 × 15 mm aluminum honeycomb plate with two arrays of 5 × 5 shunted piezoelectric patches bonded on the surface panels. Significant attenuation is found in the experimental results, which agree well with the theoretical predictions. Consequently, the proposed idea is feasible and effective.

  3. Alumina shunt for precooling a cryogen-free 4He or 3He refrigerator

    Uhlig, Kurt


    In this technical report a cryogen-free 1 K cryostat is described where the pot of the 4He refrigeration unit is precooled by the 2nd stage of a pulse tube cryocooler (PTC) from room temperature to T ∼ 3 K via a shunt made from sintered alumina (SA); the total mass of the 1 K stage is 3.5 kg. SA has high thermal conductivity at high temperatures; but below ∼50 K the thermal conductivity drops rapidly, almost following a T3-law. This makes SA an interesting candidate for the construction of a thermal shunt, especially as the heat capacity of metals drops by several orders of magnitude in the temperature range from 300 K to 3 K. At the base temperature of the PTC, the heat conduction of the shunt is so small that the heat leak into the 1 K stage is negligible.

  4. Wave propagation in beams with anti-symmetric piezoelectric shunting arrays

    Sheng-Bing, Chen; Gang, Wang


    Piezoelectric shunting arrays are employed to control the wave propagation in flexible beams. Contrary to conventional symmetric configuration, a substrate beam with anti-symmetric shunting arrays is investigated by adapted transfer matrix method. Compared with symmetric scheme, the anti-symmetric one demonstrates some distinctive characteristics. Primarily, the longitudinal and flexural waves are coupled, so they are correlated and must be considered simultaneously. Moreover, the attenuation of flexural wave is much stronger in anti-symmetric scenario, while the longitudinal wave demonstrates the converse side. As a result, the anti-symmetric scheme can be utilized to improve the vibration isolation capability of shunting arrays. Finally, the theoretical analyses are validated by finite element simulations. Project supported by the National Natural Science Foundation of China (Grant No. 51322502).

  5. The Study of Magnetic Flux Shunts Effects on the Leakage Reactance of Transformers via FEM

    Karim Abbaszadeh


    Full Text Available The influence of arrangement, dimensions, and magnetic permeability of the magnetic flux shunts on the flux distribution and leakage reactance of the power transformers is studied in this paper by using a finite elements method and a simple modeling approach. By using magneto-static analysis and finite element method, first the flux distribution in the 2D model of a core-type three phase power transformer and then using the magnetic stored energy method the leakage reactance of the transformer windings is calculated. By studying the different models including magnetic flux shunts, the effect of the arrangement, geometric dimensions as well as the magnetic permeability of the magnetic flux shunt on the leakage reactance of the transformer are studied and some interesting results are obtained. It is shown that the variation of these parameters in the transformer model has significant effects on the leakage reactance of the transformer.

  6. A retrospective study of central nervous system shunt infections diagnosed in a university hospital during a 4-year period

    Coskun Erdal


    Full Text Available Abstract Background Ventriculoperitoneal (VP shunts are used for intracranial pressure management and temporary cerebrospinal fluid (CSF drainage. Infection of the central nervous system (CNS is a major cause of morbidity and mortality in patients with CSF shunts. The aim of the present study was to evaluate the clinical features, pathogens, and outcomes of 22 patients with CSF shunt infections collected over 4 years. Methods The patients with shunt insertions were evaluated using; age, sex, etiology of hydrocephalus, shunt infection numbers, biochemical and microbiological parameters, prognosis, clinical infection features and clinical outcome. Results The most common causes of the etiology of hydrocephalus in shunt infected patients were congenital hydrocephalus-myelomeningocele (32% and meningitis (23%. The commonest causative microorganism identified was Staphylococcus (S. aureus, followed by Acinetobacter spp., and S. epidermidis. Conclusion In a case of a shunt infection the timely usage of appropriate antibiotics, according to the antimicrobial susceptibility testing, and the removal of the shunt apparatus is essential for successful treatment.

  7. Semi-active control of piezoelectric coating's underwater sound absorption by combining design of the shunt impedances

    Sun, Yang; Li, Zhaohui; Huang, Aigen; Li, Qihu


    Piezoelectric shunt damping technology has been applied in the field of underwater sound absorption in recent years. In order to achieve broadband echo reduction, semi-active control of sound absorption of multi-layered piezoelectric coating by shunt damping is significant. In this paper, a practical method is proposed to control the underwater sound absorption coefficients of piezoelectric coating layers by combining design of the shunt impedance that allows certain sound absorption coefficients at setting frequencies. A one-dimensional electro-acoustic model of the piezoelectric coating and the backing is established based on the Mason equivalent circuit theory. First, the shunt impedance of the coating is derived under the constraint of sound absorption coefficient at one frequency. Then, taking the 1-3 piezoelectric composite coating as an example, the sound absorption properties of the coating shunted to the designed shunt impedance are investigated. Next, on the basis of that, an iterative method for two constrained frequencies and an optimizing algorithm for multiple constrained frequencies are provided for combining design of the shunt impedances. At last, an experimental sample with four piezoelectric material layers is manufactured, of which the sound absorption coefficients are measured in an impedance tube. The experimental results show good agreement with the finite element simulation results. It is proved that a serial R-L circuit can control the peak frequency, maximum and bandwidth of the sound absorption coefficient and the combining R-L circuits shunted to multiple layers can control the sound absorption coefficients at multiple frequencies.

  8. Peritoneovenous shunt in treatment of ascites in patients with cirrhosis. A preliminary report with special reference to pathophysiology

    Henriksen, Jens Henrik Sahl; Malchow-Møller, A; Ring-Larsen, H;


    , but detectable increment in the overall lymph drainage was only found in a patient with a very low pre-shunt value. The findings do not support the 'overflow' theory of ascites formation but rather the 'lymph imbalance' theory. For clinical evaluation of peritoneovenous shunting in the treatment of ascites...

  9. Radionuclide determination of left-to-right shunt in patients with patent ductus arteriosus

    Klepzig, H. Jr.; Sievert, H.; Mildenberger, D.; Bussmann, W.D.; Kaltenbach, M.; Standke, R.; Hoer, G.


    In 9 patients with patent ductus arteriosus, quantification of left-to-right shunt was performed with dye dilution curves after peripheral injection and with radionuclide ventriculography. The study was repeated within 7 days after successful transluminal occlusion of the ductus with an Ivalon-plug. Reproducibility of the method could be studied in one patient in whom reopening of the ductus occurred. Dye dilution curves were analyzed using the method of Carter et al. Radionuclide ventriculography was performed as a combined first-pass and equilibrium study: effective stroke volume was derived from the first pass of the tracer through the heart; during the equilibrium phase left ventricular ejection fraction (EF) and left ventricular enddiastolic volume (EDV) were evaluated. The difference between total left ventricular stroke volume (product of EF and EDV) and effective stroke volume was taken as shunt volume. This volume as a fraction of total left ventricular stroke volume resulted in percent left-to-right shunt. The sensitivity of the dye technique was 78%; a quantification of the shunt lesion was possible in 55% of all cases (shunt greater than 35%). The sensitivity of the radionuclide technique was 90%. The severity of the lesion could not be determined in one patient with a minimal shunt. After successful occlusion of the ductus, dye dilution curves normalized in all cases. Radionuclide ventriculography showed normalization in all but one patient. This patient with concomitant mitral regurgitation still showed moderate left ventricular volume overload. After occlusion, left ventricular enddiastolic volume significantly decreased (from 224 to 181 ml, p < 0.05), effective cardiac output increased (from 6186 to 7476 ml, p < 0.01) and ejection fraction remained unchanged (55 vs. 51%). (orig./TRV).

  10. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction.

    Suresh, Supraja; Black, Richard A


    Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction being the most serious. Conventional proximal shunt catheters are made from poly(dimethyl)siloxane, the walls of which are perforated with holes for the cerebrospinal fluid to pass through. The limited range of catheters, in terms of material selection and flow distribution, is responsible in large part for their poor performance. In this study, we present an alternative design of proximal catheter made of electrospun polyether urethane, and evaluate its performance in the presence of glial cells, which are responsible for shunt blockage. The viability and growth of cells on catheter materials such as poly(dimethyl)siloxane and polyurethane in the form of cast films, microfibrous mats and porous sponges were studied in the presence of proteins present in cerebrospinal fluid after 48 h and 96 h in culture. The numbers of viable cells on each substrate were comparable to untreated poly(dimethyl)siloxane, both in the presence and absence of serum proteins found in cerebrospinal fluid. A cell culture model of shunt obstruction was developed in which cells on electrospun polyether urethane catheters were subjected to flow during culture in vitro, and the degree of obstruction quantified in terms of hydraulic permeability after static and perfusion culture. The results indicate that a catheter made of electrospun polyether urethane would be able to maintain cerebrospinal fluid flow even with the presence of cells for the time period chosen for this study. These findings have implications for the design and deployment of microporous shunt catheter systems for the treatment of

  11. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    Bercu, Zachary L., E-mail:; Sheth, Sachin B., E-mail: [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States); Noor, Amir, E-mail: [The George Washington University School of Medicine and Health Sciences (United States); Lookstein, Robert A., E-mail:; Fischman, Aaron M., E-mail:; Nowakowski, F. Scott, E-mail:; Kim, Edward, E-mail:; Patel, Rahul S., E-mail: [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States)


    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  12. Pancreaticoportal Fistula and Disseminated Fat Necrosis After Revision of a Transjugular Intrahepatic Portosystemic Shunt

    Klein, Seth J., E-mail:; Saad, Nael [Washington University School of Medicine, Interventional Radiology Section, Mallinckrodt Institute of Radiology (United States); Korenblat, Kevin [Washington University School of Medicine, Division of Gastroenterology, Department of Internal Medicine (United States); Darcy, Michael D. [Washington University School of Medicine, Interventional Radiology Section, Mallinckrodt Institute of Radiology (United States)


    A 59-year old man with alcohol related cirrhosis and portal hypertension was referred for transjugular intrahepatic portosystemic shunt (TIPS) to treat his refractory ascites. Ten years later, two sequential TIPS revisions were performed for shunt stenosis and recurrent ascites. After these revisions, he returned with increased serum pancreatic enzyme levels and disseminated superficial fat necrosis; an iatrogenic pancreaticoportal vein fistula caused by disruption of the pancreatic duct was suspected. The bare area of the TIPS was subsequently lined with a covered stent-graft, and serum enzyme levels returned to baseline. In the interval follow-up period, the patient has clinically improved.

  13. Subarachnoid hemorrhage and intracereebral hematoma following lumboperitoneal shunt for pseudotumor cerebri : a rare complication.

    Suri A


    Full Text Available Placement of lumboperitoneal (LP shunt as a surgical treatment for benign intracranial hypertension (BIH is generally a safe procedure, with complications like mechanical failure, overdrainage and infections. Subarachnoid hemorrhage and intracerebral hematoma were seen after lumboperitoneal shunt in a patient having BIH. These complications were the cause of the patient′s deterioration. After removal of the hematoma and performing a decompressive procedure, patient′s neurological condition improved. The clinical features, investigations and clinical course are described and the literature reviewed.

  14. Current diagnosis and management of post-transjugular intrahepatic portosystemic shunt refractory hepatic encephalopathy.

    Pereira, Keith; Carrion, Andres F; Martin, Paul; Vaheesan, Kirubahara; Salsamendi, Jason; Doshi, Mehul; Yrizarry, Jose M


    Transjugular intrahepatic portosystemic shunt has evolved into an important option for management of complications of portal hypertension. The use of polytetrafluoroethylene covered stents enhances shunt patency. Hepatic encephalopathy (HE) remains a significant problem after TIPS placement. The approach to management of patients with refractory hepatic encephalopathy typically requires collaboration between different specialties. Patient selection for TIPS requires careful evaluation of risk factors for HE. TIPS procedure-related technical factors like stent size, attention to portosystemic pressure gradient reduction and use of adjunctive variceal embolization maybe important. Conservative medical therapy in combination with endovascular therapies often results in resolution or substantial reduction of symptoms. Liver transplantation is, however, the ultimate treatment.

  15. Implementation of FFT Algorithm using DSP TMS320F28335 for Shunt Active Power Filter

    Patel, Pinkal Jashvantbhai; Patel, Rajesh M.; Patel, Vinod


    This work presents simulation, analysis and experimental verification of Fast Fourier Transform (FFT) algorithm for shunt active power filter based on three-level inverter. Different types of filters can be used for elimination of harmonics in the power system. In this work, FFT algorithm for reference current generation is discussed. FFT control algorithm is verified using PSIM simulation results with DLL block and C-code. Simulation results are compared with experimental results for FFT algorithm using DSP TMS320F28335 for shunt active power filter application.

  16. Value of digital subtraction angiography for the evaluation of peripheral arteriovenous shunts in patients with haemodialysis

    Beil, D.; Bolsinger, G.; Deininger, H.K.


    Direct and indirect examination of arteriovenous shunts was performed in 50 patients undergoing haemodialysis. The various methods of puncture of the vessels, the indications and the limitations of DSA are considered. The advantages of direct puncture of the arteriovenous shunt are emphasised. Puncture of the venous branch is almost without risk and allows immediate diagnosis. Only in a very few cases it will be necessary to perform the risky puncture of the arterial branch or the time-consuming central venous injection of a bolus of the contrast medium.

  17. Centerline Longitudinal Shunt Slot Excitation by Elliptic shaped single Ridge Waveguide

    Mehdi Moradian


    Full Text Available The Application of elliptic shaped ridge waveguide is presented for excitation of a centreline longitudinal shunt slot antenna. The proposed method is realized by adding elliptic shaped to the ridge of the single ridge waveguide. The elliptic shaped ridge is placed exactly under the longitudinal slot and the slot placed along centreline of the waveguide. It is shown that for a typical slot, the slot normalized conductance can be increased by increasing the elliptic shaped depth. The simulation results show that the proposed structure can be considered as a proper candidate for replacing the conventional longitudinal shunt slot.

  18. Unusual cause for ventriculoperitoneal shunt failure: Carcinoma breast compressing distal catheter

    Roka Yam


    Full Text Available Insertion of a ventriculoperitoneal (VP shunt is one of the most common surgical procedures in any neurosurgery unit worldwide. Distal catheter obstruction outside the peritoneum is a rare cause of shunt failure. We report the first case of distal obstruction in a 70-year old female by carcinoma breast engulfing the catheter and causing kinking. Intraoperatively, the catheter was intratumoral with no flow of cerebrospinal fluid distally. She underwent relocation of a new catheter to the opposite side of the abdomen and modified mastectomy with resolution of the hydrocephalus. The postoperative course has been uneventful.

  19. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi


    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs.

  20. Radiation Exposure in Transjugular Intrahepatic Portosystemic Shunt Creation

    Miraglia, Roberto, E-mail:; Maruzzelli, Luigi, E-mail:; Cortis, Kelvin, E-mail: [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy); D’Amico, Mario, E-mail: [University of Palermo, Department of Radiology (Italy); Floridia, Gaetano, E-mail:; Gallo, Giuseppe, E-mail:; Tafaro, Corrado, E-mail:; Luca, Angelo, E-mail: [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy)


    PurposeTransjugular intrahepatic portosystemic shunt (TIPS) creation is considered as being one of the most complex procedures in abdominal interventional radiology. Our aim was twofold: quantification of TIPS-related patient radiation exposure in our center and identification of factors leading to reduced radiation exposure.Materials and methodsThree hundred and forty seven consecutive patients underwent TIPS in our center between 2007 and 2014. Three main procedure categories were identified: Group I (n = 88)—fluoroscopic-guided portal vein targeting, procedure done in an image intensifier-based angiographic system (IIDS); Group II (n = 48)—ultrasound-guided portal vein puncture, procedure done in an IIDS; and Group III (n = 211)—ultrasound-guided portal vein puncture, procedure done in a flat panel detector-based system (FPDS). Radiation exposure (dose-area product [DAP], in Gy cm{sup 2} and fluoroscopy time [FT] in minutes) was retrospectively analyzed.ResultsDAP was significantly higher in Group I (mean ± SD 360 ± 298; median 287; 75th percentile 389 Gy cm{sup 2}) as compared to Group II (217 ± 130; 178; 276 Gy cm{sup 2}; p = 0.002) and Group III (129 ± 117; 70; 150 Gy cm{sup 2}p < 0.001). The difference in DAP between Groups II and III was also significant (p < 0.001). Group I had significantly longer FT (25.78 ± 13.52 min) as compared to Group II (20.45 ± 10.87 min; p = 0.02) and Group III (19.76 ± 13.34; p < 0.001). FT was not significantly different between Groups II and III (p = 0.73).ConclusionsReal-time ultrasound-guided targeting of the portal venous system during TIPS creation results in a significantly lower radiation exposure and reduced FT. Further reduction in radiation exposure can be achieved through the use of modern angiographic units with FPDS.

  1. When do the symptoms of autonomic nervous system malfunction appear in patients with Parkinson’s disease?

    De Luka Silvio R.


    Full Text Available Background/Aim. Dysautonomia appears in almost all patients with Parkinson’s disease (PD in a certain stage of their condition. The aim of our study was to detect the development and type of autonomic disorders, find out the factors affecting their manifestation by analyzing the potential association with demographic variables related to clinical presentation, as well as the symptoms of the disease in a PD patient cohort. Methods. The patients with PD treated at the Clinic of Neurology in Belgrade during a 2-year period, divided into 3 groups were studied: 25 de novo patients, 25 patients already treated and had no long-term levodopa therapy-related complications and 22 patients treated with levodopa who manifested levodopa-induced motor complications. Simultaneously, 35 healthy control subjects, matched by age and sex, were also analyzed. Results. Autonomic nervous system malfunction was defined by Ewing diagnostic criteria. The tests, indicators of sympathetic and parasympathetic nervous systems, were significantly different in the PD patients as compared with the controls, suggesting the failure of both systems. However, it was shown, in the selected groups of patients, that the malfunction of both systems was present in two treated groups of PD patients, while de novo group manifested only sympathetic dysfunction. For this reason, the complete autonomic neuropathy was diagnosed only in the treated PD patients, while de novo patients were defined as those with the isolated sympathetic dysfunction. The patients with the complete autonomic neuropathy differed from the subjects without such neuropathy in higher cumulative and motor unified Parkinson’s disease rating score (UPDRS (p < 0.01, activities of daily living scores (p < 0.05, Schwab-England scale (p < 0.001 and Hoehn-Yahr scale. There was no difference between the patients in other clinical-demographic characteristics (sex, age at the time of diagnosis, actual age, duration of

  2. Co-Localization of GABA Shunt Enzymes for the Efficient Production of Gamma-Aminobutyric Acid via GABA Shunt Pathway in Escherichia coli.

    Pham, Van Dung; Somasundaram, Sivachandiran; Park, Si Jae; Lee, Seung Hwan; Hong, Soon Ho


    Gamma-aminobutyric acid (GABA) is a non-protein amino acid, which is an important inhibitor of neurotransmission in the human brain. GABA is also used as the precursor of biopolymer Nylon-4 production. In this study, the carbon flux from the tricarboxylic acid cycle was directed to the GABA shunt pathway for the production of GABA from glucose. The GABA shunt enzymes succinate-semialdehyde dehydrogenase (GabD) and GABA aminotransferase (GabT) were co-localized along with the GABA transporter (GadC) by using a synthetic scaffold complex. The co-localized enzyme scaffold complex produced 0.71 g/l of GABA from 10 g/l of glucose. Inactivation of competing metabolic pathways in mutant E. coli strains XBM1 and XBM6 increased GABA production 13% to reach 0.80 g/l GABA by the enzymes co-localized and expressed in the mutant strains. The recombinant E. coli system developed in this study demonstrated the possibility of the pathway of the GABA shunt as a novel GABA production pathway.

  3. Shunt and series resistance of photovoltaic module evaluated from the I-V curve; I-V tokusei kara hyokashita taiyo denchi no shunt teiko to chokuretsu teiko

    Asano, K.; Kawamura, H.; Yamanaka, S.; Kawamura, H.; Ono, H. [Meijo University, Nagoya (Japan)


    With an objective of discussing I-V characteristics when a shadow has appeared on part of a photovoltaic module, evaluations were given as a first stage of the study on saturation current, shunt resistance and series resistance for the solar cell module. As a result of measuring change in amount of power generated in a sunny day with a shadow appearing over the solar cell module, reduction in power generation capability of about 23% was verified. In other words, the I-V characteristics of the solar cell module change largely because of existence of the shadow caused on the module. The I-V characteristics curve may be expressed and calculated as a function of the shunt resistance and series resistance. By curve-fitting measurement data for a case of changing insolation without existence of partial shadow, values of the shunt resistance and series resistance were derived. As a result, it was found that the calculations agree well with measurements. It was made also clear that each parameter shows temperature dependence. 6 refs., 10 figs., 1 tab.

  4. Cerebrospinal fluid pulse pressure amplitude during lumbar infusion in idiopathic normal pressure hydrocephalus can predict response to shunting

    Brean Are


    Full Text Available Abstract Background We have previously seen that idiopathic normal pressure hydrocephalus (iNPH patients having elevated intracranial pressure (ICP pulse amplitude consistently respond to shunt surgery. In this study we explored how the cerebrospinal fluid pressure (CSFP pulse amplitude determined during lumbar infusion testing, correlates with ICP pulse amplitude determined during over-night ICP monitoring and with response to shunt surgery. Our goal was to establish a more reliable screening procedure for selecting iNPH patients for shunt surgery using lumbar intrathecal infusion. Methods The study population consisted of all iNPH patients undergoing both diagnostic lumbar infusion testing and continuous over-night ICP monitoring during the period 2002-2007. The severity of iNPH was assessed using our NPH grading scale before surgery and 12 months after shunting. The CSFP pulse was characterized from the amplitude of single pressure waves. Results Totally 62 iNPH patients were included, 45 of them underwent shunt surgery, in whom 78% were shunt responders. Among the 45 shunted patients, resistance to CSF outflow (Rout was elevated (≥ 12 mmHg/ml/min in 44. The ICP pulse amplitude recorded over-night was elevated (i.e. mean ICP wave amplitude ≥ 4 mmHg in 68% of patients; 92% of these were shunt responders. In those with elevated overnight ICP pulse amplitude, we found also elevated CSFP pulse amplitude recorded during lumbar infusion testing, both during the opening phase following lumbar puncture and during a standardized period of lumbar infusion (15 ml Ringer over 10 min. The clinical response to shunting after 1 year strongly associated with the over-night ICP pulse amplitude, and also with the pulsatile CSFP during the period of lumbar infusion. Elevated CSFP pulse amplitude during lumbar infusion thus predicted shunt response with sensitivity of 88 and specificity of 60 (positive and negative predictive values of 89 and 60

  5. The living shunt: a tissue engineering approach in the treatment of hydrocephalus.

    Lee, I W; Vacanti, J P; Taylor, G A; Madsen, J R


    Tissue engineering is the use of cultured cells seeded into biodegradable polymers to create custom designed, living implantable devices. As a first approach to the use of this technique in the treatment of hydrocephalus, we have prepared chondrocyte-seeded polyglycolic acid (PGA) tubes coated with polylactic glycolic acid (PGLA), implanted initially with thin silastic stents removed four weeks after shunt insertion. The use of bovine xenograft cells in athymic (nude) rats resulted in more efficient seeding with chondrocytes, stiffer tube walls, and better patency. When implanted in 6-week-old rats made hydrocephalic by cisternal injection of kaolin at 4 weeks of age, six of eight 'living shunts' remained patent to radio-opaque contrast injection at two weeks after stent removal. At four weeks after stent removal, all four of the shunts had occluded at the ventricular end, three of the four apparently due to growth of the animal. We conclude that polymer type, cell type, and cell density will require considerable optimization, but a working tissue engineered shunt is feasible and may one day address some problems of interactions of living tissue and inert polymer.

  6. Evaluation of hepatic steatosis in dogs with congenital portosystemic shunts using Oil Red O staining.

    Hunt, G B; Luff, J A; Daniel, L; Van den Bergh, R


    The aims of this prospective study were to quantify steatosis in dogs with congenital portosystemic shunts (CPS) using a fat-specific stain, to compare the amount of steatosis in different lobes of the liver, and to evaluate intra- and interobserver variability in lipid point counting. Computer-assisted point counting of lipid droplets was undertaken following Oil Red O staining in 21 dogs with congenital portosystemic shunts and 9 control dogs. Dogs with congenital portosystemic shunts had significantly more small lipid droplets (dogs (P = .0013 and .0002, respectively). There was no significant difference in steatosis between liver lobes for either control dogs and CPS dogs. Significant differences were seen between observers for the number of large lipid droplets (>9 μ) and lipogranulomas per tissue point (P = .023 and .01, respectively). In conclusion, computer-assisted counting of lipid droplets following Oil Red O staining of liver biopsy samples allows objective measurement and detection of significant differences between dogs with CPS and normal dogs. This method will allow future evaluation of the relationship between different presentations of CPS (anatomy, age, breed) and lipidosis, as well as the impact of hepatic lipidosis on outcomes following surgical shunt attenuation.

  7. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    Cardella, Davide; Celli, Paolo; Gonella, Stefano


    In this work, we propose and test a strategy for tunable, broadband wave attenuation in electromechanical waveguides with shunted piezoelectric inclusions. Our strategy is built upon the vast pre-existing literature on vibration attenuation and bandgap generation in structures featuring periodic arrays of piezo patches, but distinguishes itself for several key features. First, we demystify the idea that periodicity is a requirement for wave attenuation and bandgap formation. We further embrace the idea of ‘organized disorder’ by tuning the circuits as to resonate at distinct neighboring frequencies. In doing so, we create a tunable ‘rainbow trap’ (Tsakmakidis et al 2007 Nature 450 397-401) capable of attenuating waves with broadband characteristics, by distilling (sequentially) seven frequencies from a traveling wavepacket. Finally, we devote considerable attention to the implications in terms of packet distortion of the spectral manipulation introduced by shunting. This work is also meant to serve as a didactic tool for those approaching the field of shunted piezoelectrics, and attempts to provide a different perspective, with abundant details, on how to successfully design an experimental setup involving resistive-inductive shunts.

  8. Experimental results of the tracheoesophageal tissue connector for improved fixation of shunt valves in laryngectomized patients

    ten Hallers, E. J. Olivier; Marres, Henri A. M.; van der Houwen, Eduard B.; Jansen, John A.; Rakhorst, Gerhard; Schutte, Harm K.; van Kooten, Theo G.; van Loon, Jan-Paul; Verkerke, Gijsbertus J.


    Background, After total laryngectomy and voice rehabilitation using a tracheoesophageal shunt valve, patients often have valve-related complications such as leakage. To solve these problems, a tracheoesophageal tissue connector (TE-TC) was devised to serve as an interface between the patient's tissu

  9. Optimally tuned resonant negative capacitance for piezoelectric shunt damping based on measured electromechanical impedance

    Salloum, Rogério; Heuss, Oliver; Götz, Benedict; Mayer, Dirk


    In this paper, a new tuning method for shunt damping with a series resistance, inductance and negative capacitance is proposed and its validity is investigated. It is based on the measured electromechanical impedance of a piezoelectric system, which is represented through an equivalent electrical circuit that takes into account the characteristics of the piezoelectric transducer and the host structure. Afterwards, an additional circuit representing the shunt is connected and the Norton equivalent impedance is obtained at the terminals that represent the mechanical mode of interest. During the tuning process, the optimal shunt parameters are found by minimizing the maximum absolute value of the Norton equivalent impedance over a defined frequency range through a numerical optimization. Taking benefit from the analogy between electrical impedance and mechanical admittance, the minimization of different mechanical responses (displacement, velocity or acceleration) is also proposed and the different optimum shunt parameters obtained are compared. In view of real technical applications, this method allows the integration of a real negative capacitance circuit, i.e., a negative impedance converter, rather than an ideal component. It is thus possible to use the impedance of this circuit and optimize the individual component values. Since this method is based on one simple measurement, it can be applied to arbitrary structures without the need of complex dynamic tests or expensive finite elements calculations. Finally, an experimental analysis is carried out in order to compare the damping performance of the proposed method and the conventional analytical method that minimizes a mechanical frequency response function.

  10. Outcome of endoscopic third ventriculostomy and Chhabra shunt system in noncommunicating non-tumor childhood hydrocephalus

    O E Idowu


    Full Text Available Background : Endoscopic third ventriculostomy (ETV the main alternative to ventriculoperitoneal shunt (VPS is just beginning to have a foothold in West Africa. It provides a great opportunity for a hydrocephalic child to be shunt free. The purpose of this paper is to compare outcome following ETV and VPS (using the cheap Chhabra shunt in children with noncommunicating non-tumoral hydrocephalus in an environment where late presentation is the norm. Materials and Methods : Sixty-three pediatric patients (< 6 years with hydrocephalus who underwent a VPS or ETV at our hospital were included in this study. The study period was of 30 months (January 2006 till June 2008. Clinically successful outcome was defined as no event occurring during or after surgery that resulted in an alternate surgical procedure, or significant post-operative complication that includes death. All complications related to the procedures were also analyzed. Results : The outcome of surgical intervention was not significantly related to the gender, age of the patient at surgery, or type of surgery. The post-operative complication rate was similar in both groups. Conclusions : The clinical outcome of ETV is comparable to that of VPS, with the added benefit of no shunt-related problems; and being a short procedure, patient anesthesia and operation time, hospital stay, and cost are significantly reduced. We consider ETV to be the procedure of choice for the treatment of noncommunicating nontumoral hydrocephalus in the pediatric population.

  11. Alteration of brain viscoelasticity after shunt treatment in normal pressure hydrocephalus

    Freimann, Florian Baptist; Sprung, Christian [Charite - University Medicine Berlin, Campus Virchow-Klinikum, Neurosurgical Department, Berlin (Germany); Streitberger, Kaspar-Josche; Klatt, Dieter; Sack, Ingolf [Charite - University Medicine Berlin, Campus Charite Mitte, Department of Radiology, Berlin (Germany); Lin, Kui; McLaughlin, Joyce [Rensselaer Polytechnic Institute, Mathematics Department, Troy, NY (United States); Braun, Juergen [Charite - University Medicine Campus Benjamin Franklin, Institute of Medical Informatics, Berlin (Germany)


    Normal pressure hydrocephalus (NPH) represents a chronic neurological disorder with increasing incidence. The symptoms of NPH may be relieved by surgically implanting a ventriculoperitoneal shunt to drain excess cerebrospinal fluid. However, the pathogenesis of NPH is not yet fully elucidated, and the clinical response of shunt treatment is hard to predict. According to current theories of NPH, altered mechanical properties of brain tissue seem to play an important role. Magnetic resonance elastography (MRE) is a unique method for measuring in vivo brain mechanics. In this study cerebral MRE was applied to test the viscoelastic properties of the brain in 20 patients with primary (N = 14) and secondary (N = 6) NPH prior and after (91 {+-} 16 days) shunt placement. Viscoelastic parameters were derived from the complex modulus according to the rheological springpot model. This model provided two independent parameters {mu} and {alpha}, related to the inherent rigidity and topology of the mechanical network of brain tissue. The viscoelastic parameters {mu} and {alpha} were found to be decreased with -25% and -10%, respectively, compared to age-matched controls (P < 0.001). Interestingly, {alpha} increased after shunt placement (P < 0.001) to almost normal values whereas {mu} remained symptomatically low. The results indicate the fundamental role of altered viscoelastic properties of brain tissue during disease progression and tissue repair in NPH. Clinical improvement in NPH is associated with an increasing complexity of the mechanical network whose inherent strength, however, remains degraded. (orig.)

  12. Accurate calibration of RL shunts for piezoelectric vibration damping of flexible structures

    Høgsberg, Jan Becker; Krenk, Steen


    Piezoelectric RL (resistive-inductive) shunts are passive resonant devices used for damping of dominantvibration modes of a flexible structure and their efficiency relies on precise calibration of the shuntcomponents. In the present paper improved calibration accuracy is attained by an extension ...

  13. Electrochemical etching of molybdenum for shunt removal in thin film solar cells

    Hovestad, A.; Bressers, P.M.M.C.; Meertens, R.M.; Frijters, C.H.; Voorthuijzen, W.P.


    High yield and reproducible production is a major challenge in up-scaling thin film Cu(In,Ga)Se2(CIGS) solar cells to large area roll-to-roll industrial manufacturing. Pinholes enabling Ohmic contact between the ZnO:Al front-contact and Mo back contact of the CIGS cell create electrical shunts that

  14. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural waves

    Chen, Y. Y.; Hu, G. K.; Huang, G. L.


    A great deal of research has been devoted to controlling the dynamic behaviors of phononic crystals and metamaterials by directly tuning the frequency regions and/or widths of their inherent band gaps. Here, we report a new class of adaptive metamaterial beams with hybrid shunting circuits to realize super broadband Lamb-wave band gaps at an extreme subwavelength scale. The proposed metamaterial is made of a homogeneous host beam on which tunable local resonators consisting of hybrid shunted piezoelectric stacks with proof masses are attached. The hybrid shunting circuits are composed of negative-capacitance and negative-inductance elements connected in series or in parallel in order to tune the desired frequency-dependent stiffness. It is shown theoretically and numerically that by properly modifying the shunting impedance, the adaptive mechanical mechanism within the tunable resonator can produce high-pass and low-pass wave filtering capabilities for the zeroth-order anti-symmetric Lamb-wave modes. These unique behaviors are due to the hybrid effects from the negative-capacitance and negative-inductance circuit elements. Such a system opens up important perspectives for the development of adaptive vibration or wave-attenuation devices for broadband frequency applications.

  15. Sensitivity analysis and control of a cantilever beam by mean of a shunted piezoelectric patch

    Matten, Gaël; Collet, Manuel; Sadoulet-Reboul, Emeline; Cogan, Scott


    International audience; In this paper, a sensitivity analysis of a beam controlled with a shunted piezoelectric patch is presented. A negative capacitance controller is implemented and a study of stability and performance is performed. Besides, the effects of the technological aspects such as the variability in the material properties or in the position of the piezoelectric patch is evaluated through a finite element simulation

  16. Ventriculopleural Shunt Surgery in A Patient with Multiple Skeletal and Neurodevelopmental Anomalies: A True Perioperative Challenge

    Ashish K. Khanna


    Full Text Available Introduction: Ventriculopleural shunt placement for decompression of hydrocephalous is an uncommon procedure. The usual indications are adhesions, infection, thrombosis or obliteration of the more commonly done ventriculoperitoneal shunt or an anatomical non-availability of the peritoneum. We present a clinical case of a patient with congenital hydrocephalous complicated by multiple skeletal and neurodevelopmental anomalies who presented for thoracoscopic placement of a ventriculopleural shunt. The anesthetic challenges and perioperative management constituted a complex multi-disciplinary challenge. Case presentation: We present a clinical case of a 42 years old woman with congenital hydrocephalous complicated by multiple skeletal and neurodevelopmental anomalies who presented for thoracoscopic placement of a ventriculopleural shunt. Some of the perioperative concerns included initiation and maintenance of one-lung ventilation in a patient with short stature, dysmorphic skeletal features, severe kyphoscoliosis, restrictive underlying lung disease and multiple neurodevelopmental midline defects. Conclusion: Our presentation highlights the special challenges in this patient based on the need for lung collapse in a severely short statured individual with a dysmorphic severely kyphoscoliotic thoracic cavity along with underlying restrictive lung disease and background neurodevelopmental midline defects.

  17. Increased myocardial lactate oxidation in lambs with aortopulmonary shunts at rest and during exercise

    Beaufort-Krol, GCM; Takens, J; Molenkamp, MC; Smid, GB; Meuzelaar, KJ; Zijlstra, WG; Kuipers, JRG


    Free fatty acids are the major fuels for the myocardium, but during a higher load carbohydrates are preferred. Previously, we demonstrated that myocardial net lactate uptake was higher in lambs with aortopulmonary shunts than in control lambs. To determine whether this was caused by an increased lac


    Fanta, S M


    There were examined 134 patients, in whom in the clinic in 2005-2014 yrs a coronary shunting operation was performed. In patients with the angina pectoris recurrence a reoperation is indicated. The data of repeated coronaroventriculography and shuntography were analyzed. Efficacy of the surgical and interventional methods application in the patients was proved.

  19. Role of kinetic inductance in transport properties of shunted superconducting nanowires.

    Lin, Shi-Zeng; Roy, Dibyendu


    Recently, transport measurements have been carried out in resistively shunted long superconducting nanowires (Brenner et al 2012 Phys. Rev. B 85 224507). The measured voltage-current (V-I) characteristics were explained by the appearance of the phase slip centers in the shunted wire, and the whole wire was modeled as a single Josephson junction. The kinetic inductance of the long nanowires used in experiments is generally large. Here we argue that the shunted superconducting nanowire acts as a Josephson junction in series with an inductor. The inductance depends on the length and the cross section of the wire. The inclusion of inductance in our analysis modifies the V-I curves, and increases the rate of switching from the superconducting state to the resistive state. The quantitative differences can be quite large in some practical parameter sets, and might be important to properly understand the experimental results. Our proposed model can be verified experimentally by studying the shunted superconducting nanowires of different lengths and cross sections.

  20. Multi-Rate Fractional-Order Repetitive Control of Shunt Active Power Filter

    Xie, Chuan; Zhao, Xin; Savaghebi, Mehdi


    This paper presents a multi-rate fractional-order repetitive control (MRFORC) scheme for three-phase shunt active power filter (APF). The proposed APF control scheme includes an inner proportional-integral (PI) control loop with a sampling rate identical to switching frequency and an external plug-in...

  1. The G6. A heavy-duty, six-wheeled shunting locomotive

    Hildebrandt, Tim [Vossloh Locomotives GmbH, Kiel (Germany). Development and Standardisation Group


    Nowadays, railway operating companies need robust, reliable and versatile locomotives. Vossloh has shown one way that future developments are likely to go with its 'G6' six-wheeled shunting locomotive, which features a central driver's cab. (orig.)

  2. Almost periodic solution of shunting inhibitory cellular neural networks with time-varying delay

    Huang Xia; Cao Jinde


    Several sufficient conditions are obtained for the existence of almost periodic solution and its attractivity of shunting inhibitory cellular neural networks with time-varying delay based on the fixed point method and Halanay inequality technique. Some previous results are improved and extended in this Letter and two examples are given to illustrate the effectiveness of the new results.

  3. A novel technique to treat acquired Chiari I malformation after supratentorial shunting

    Potgieser, Adriaan R E; Hoving, Eelco W


    PURPOSE: The acquired Chiari I malformation with abnormal cranial vault thickening is a rare late complication of supratentorial shunting. It poses a difficult clinical problem, and there is debate about the optimal surgical strategy. Some authors advocate supratentorial skull enlarging procedures w

  4. Analysis of postural sway in patients with normal pressure hydrocephalus: effects of shunt implantation

    Czerwosz L


    Full Text Available Abstract Poor postural balance is one of the major risk factors for falling in normal pressure hydrocephalus (NPH. Postural instability in the clinic is commonly assessed based upon force platform posturography. In this study we focused on the identification of changes in sway characteristics while standing quiet in patients with NPH before and after shunt implantation. Postural sway area and sway radius were analyzed in a group of 9 patients and 46 controls of both genders. Subject's spontaneous sway was recorded while standing quiet on a force platform for 30-60 s, with eyes open and then closed. Both analyzed sway descriptors identified between-group differences and also an effect of shunt implantation in the NPH group. Sway radius and sway area in patients exhibited very high values compared with those in the control group. Importantly, the effect of eyesight in patients was not observed before shunt implantation and reappeared after the surgical treatment. The study documents that static force platform posturography may be a reliable measure of postural control improvement due to shunt surgery.

  5. Accurate phasor measurement for transmission line protection in the presence of shunt capacitor banks

    Nam, Soon-Ryul; Kang, Sang-Hee [Department of Electrical Engineering and Next-Generation Power Technology Center, Myongji University (Korea); Park, Jong-Keun [School of Electrical Engineering, Seoul National University (Korea)


    This paper proposes a phasor measurement algorithm for transmission systems compensated with shunt capacitor banks. Since the shunt capacitor banks tend to lower the resonant frequencies, the dominant component, which has the lowest resonant frequency, is insufficiently attenuated by a low-pass filter and has an adverse influence on the phasor measurement of the fundamental component in a fault current signal. This paper theoretically investigates the dominant frequency in the presence of shunt capacitor banks and presents a phasor measurement algorithm immune to the dominant component and DC-offset. The performance of the algorithm is evaluated for a-phase to ground (a-g) faults on a 154-kV transmission system compensated with shunt capacitor banks. The evaluation results indicate that the algorithm can measure the phasor reliably and satisfactorily, although the fault current signal is distorted with the dominant component and DC-offset. The paper concludes by describing the hardware implementation of the algorithm on a prototype unit based on a digital signal processor. (author)

  6. Favorable outcome of neonatal cerebrospinal fluid shunt-associated Candida meningitis with caspofungin

    Jans, J.; Bruggemann, R.J.M.; Christmann, V.; Verweij, P.E.; Warris, A.


    Invasive Candida infections associated with medical devices are very difficult to cure without device removal. We present a case of neonatal cerebrospinal fluid shunt-associated Candida meningitis, in which removal of the device was precluded, that was successfully treated with caspofungin. Pharmaco

  7. Analysis of postural sway in patients with normal pressure hydrocephalus: effects of shunt implantation.

    Czerwosz, L; Szczepek, E; Blaszczyk, J W; Sokolowska, B; Dmitruk, K; Dudzinski, K; Jurkiewicz, J; Czernicki, Z


    Poor postural balance is one of the major risk factors for falling in normal pressure hydrocephalus (NPH). Postural instability in the clinic is commonly assessed based upon force platform posturography. In this study we focused on the identification of changes in sway characteristics while standing quiet in patients with NPH before and after shunt implantation. Postural sway area and sway radius were analyzed in a group of 9 patients and 46 controls of both genders. Subject's spontaneous sway was recorded while standing quiet on a force platform for 30-60 s, with eyes open and then closed. Both analyzed sway descriptors identified between-group differences and also an effect of shunt implantation in the NPH group. Sway radius and sway area in patients exhibited very high values compared with those in the control group. Importantly, the effect of eyesight in patients was not observed before shunt implantation and reappeared after the surgical treatment. The study documents that static force platform posturography may be a reliable measure of postural control improvement due to shunt surgery.

  8. Low-dose acetylsalicylic acid and bleeding risks with ventriculoperitoneal shunt placement.

    Kamenova, Maria; Croci, Davide; Guzman, Raphael; Mariani, Luigi; Soleman, Jehuda


    OBJECTIVE Ventriculoperitoneal (VP) shunt placement is a common procedure for the treatment of hydrocephalus following diverse neurosurgical conditions. Most of the patients present with other comorbidities and receive antiplatelet therapy, usually acetylsalicylic acid (ASA). Despite its clinical relevance, the perioperative management of these patients has not been sufficiently investigated. The aim of this study was to compare the peri- and postoperative bleeding complication rates associated with ASA intake in patients undergoing VP shunt placement. METHODS Of 172 consecutive patients undergoing VP shunt placement between June 2009 and December 2015, 40 (23.3%) patients were receiving low-dose ASA treatment. The primary outcome measure was bleeding events in ASA users versus nonusers, whereas secondary outcome measures were postoperative cardiovascular events, hematological findings, morbidity, and mortality. A subgroup analysis was conducted in patients who discontinued ASA treatment for < 7 days (n = 4, ASA Group 1) and for ≥ 7 days (n = 36, ASA Group 2). RESULTS No statistically significant difference for bleeding events was observed between ASA users and nonusers (p = 0.30). Cardiovascular complications, surgical morbidity, and mortality did not differ significantly between the groups either. Moreover, there was no association between ASA discontinuation regimens (< 7 days and ≥ 7 days) and hemorrhagic events. CONCLUSIONS Given the lack of guidelines regarding perioperative management of neurosurgical patients with antiplatelet therapy, these findings elucidate one issue, showing comparable bleeding rates in ASA users and nonusers undergoing VP shunt placement.

  9. The interrelations between malfunctioning DNA damage response (DDR) and the functionality of the neuro-glio-vascular unit.

    Barzilai, Ari


    A hallmark of neurodegenerative diseases is impairment of certain aspects of "brain functionality". Brain functionality is defined as the total input and output of the brain's neural circuits and networks. A given brain degenerative disorder does not deregulate total brain functionality but rather the activity of specific circuits in a given network, affecting their organization and topology, their cell numbers, their cellular functionality, and the interactions between neural circuits. Similarly, our concept of neurodegenerative diseases, which for many years revolved around neural survival or death, has now been extended to emphasize the role of glia. In particular, the role of glial cells in neuro-vascular communication is now known to be central to the effect of insults to the nervous system. In addition, a malfunctioning vascular system likely plays a role in the etiology of certain neurodegenerative diseases. Thus, the symptoms of neurodegenerative or more correctly brain degenerative disease are, to a very large extent, a result of impairment in glial cells that lead to pathological neuro-vascular interactions that, in turn, generate a rather "hostile" environment in which the neurons fail to function. These events lead to systematic neural cell death on a scale that appears to be proportional to the severity of the neurological deficit.

  10. Evolving Insights into the Pathophysiology of Diabetic Neuropathy: Implications of Malfunctioning Glia and Discovery of Novel Therapeutic Targets.

    Rahman, Md Habibur; Jha, Mithilesh Kumar; Suk, Kyoungho


    Diabetic neuropathy subsequent to chronic high blood glucose-induced nerve damage is one of the most frustrating and debilitating complications of diabetes, which affects the quality of life in patients with diabetes. Approximately 60-70% of patients with diabetes suffer from a distal symmetrical form of mild to severe neuropathy that progresses in a fiber-length-dependent pattern, with sensory and autonomic manifestations predominating. High glucose and oxidative stress-mediated damage in neurons and glial cells, as well as neuroinflammation and crosstalk between these disease processes, have garnered immense attention as the essential mechanisms underlying the development and progression of diabetic neuropathy. Although the metabolic causes of diabetic neuropathy are well understood and documented, treatment options for this disorder are still limited, highlighting the need for further studies to identify new molecular and therapeutic targets. This review covers recent advances in our knowledge of the pathophysiology of diabetic neuropathy, discusses how persistent hyperglycemic conditions and malfunctioning glia drive disease progression, and finally explores the possibilities and challenges offered by several potential novel therapeutic targets for both preventing and reversing diabetic neuropathy.

  11. Radionuclide Angiocardiographic Evaluation of Left-to-Right Cardiac Shunts: Analysis of Time-Active Curves

    Kim, Ok Hwa; Bahk, Yong Whee; Kim, Chi Kyung [Catholic University College of Medicine, Seoul (Korea, Republic of)


    The noninvasive nature of the radionuclide angiocardiography provided a useful approach for the evaluation of left-to-right cardiac shunts (LRCS). While the qualitative information can be obtained by inspection of serial radionuclide angiocardiograms, the quantitative information of radionuclide angiocardiography can be obtained by the analysis of time-activity curves using advanced computer system. The count ratios method and pulmonary-to-systemic flow ratio (QP/QS) by gamma variate fit method were used to evaluate the accuracy of detection and localization of LRCS. One hundred and ten time-activity curves were analyzed. There were 46 LRCS (atrial septal defects 11, ventricular septal defects 22, patent ductus arteriosus 13) and 64 normal subjects. By computer analysis of time-activity curves of the right atriurn, ventricle and the lungs separately, the count ratios modified by adding the mean cardiac transit time were calculated in each anatomic site. In normal subjects the mean count ratios in the right atrium, ventricle and lungs were 0.24 on average. In atrial septal defects, the count ratios were high in the right atrium, ventricle and lungs, whereas in ventricular septal defects the count ratios were higher only in the right ventricle and lungs. Patent ductus arteriosus showed normal count ratios in the heart but high count ratios were obtained in the lungs. Thus, this count ratios method could be separated normal from those with intracardiac or extracardiac shunts, and moreover, with this method the localization of the shunt level was possible in LRCS. Another method that could differentiate the intracardiac shunts from extracardiac shunts was measuring QP/QS in the left and right lungs. In patent ductus arteriosus, the left lung QP/QS was higher than those of the right lung, whereas in atrial septal defects and ventricular septal defects QP/ QS ratios were equal in both lungs. From this study, it was found that by measuring QP/QS separately in the lungs

  12. Piezoelectric Shunt Vibration Damping of F-15 Panel under High Acoustic Excitation

    Wu, Shu-Yau; Turner, Travis L.; Rizzi, Stephen A.


    At last year's SPIE symposium, we reported results of an experiment on structural vibration damping of an F-15 underbelly panel using piezoelectric shunting with five bonded PZT transducers. The panel vibration was induced with an acoustic speaker at an overall sound pressure level (OASPL) of about 90 dB. Amplitude reductions of 13.45 and 10.72 dB were achieved for the first and second modes, respectively, using single- and multiple-mode shunting. It is the purpose of this investigation to extend the passive piezoelectric shunt-damping technique to control structural vibration induced at higher acoustic excitation levels, and to examine the controllability and survivability of the bonded PZT transducers at these high levels. The shunting experiment was performed with the Thermal Acoustic Fatigue Apparatus (TAFA) at the NASA Langley Research Center using the same F-15 underbelly panel. The TAFA is a progressive wave tube facility. The panel was mounted in one wall of the TAFA test section using a specially designed mounting fixture such that the panel was subjected to grazing-incidence acoustic excitation. Five PZT transducers were used with two shunt circuits designed to control the first and second modes of the structure between 200 and 400 Hz. We first determined the values of the shunt inductance and resistance at an OASPL of 130 dB. These values were maintained while we gradually increased the OASPL from 130 to 154 dB in 6-dB steps. During each increment, the frequency response function between accelerometers on the panel and the acoustic excitation measured by microphones, before and after shunting, were recorded. Good response reduction was observed up to the 148dB level. The experiment was stopped at 154 dB due to wire breakage from vibration at a transducer wire joint. The PZT transducers, however, were still bonded well on the panel and survived at this high dB level. We also observed shifting of the frequency peaks toward lower frequency when the OASPL

  13. No special management for peritoneal catheter in ventriculo -peritoneal shunt is required%脑室-腹腔分流术中分流管腹腔端无需特殊处理

    梁玉敏; 高国一; 包映晖; 丁圣豪; 潘耀华; 吴海波; 陈磊; 江基尧


    Objective To investigate the dynamic changes of peritoneal catheter of ventriculoperitoneal shunt (V- P shunt) prospectively,and to determine simple,effective disposal method of peritoneal catheter.Method From Jan 2007 to Oct 2010,consecutive 40 patients with hydrocephalus were treated by V - P shunt.All patients were operated through puncture of frontal horn of lateral ventricle.And 4 cm straight abdominal incision under xiphoid was made and after shunt system had been connected well,the abdominal catheter was put into peritoneal cavity through 3 mm incision of peritoneum.Head CT scans were regularly made at the 1st,3rd and 7th day after shunt to determine the intracranial state for all patients,and abdominal X - ray plain films were also obtained to confirm the position of peritoneal catheters at the same time.All the clinical data and results of follow - up were reviewed.Results Dynamic head CT scans showed good results of V - P shunt after surgery in all cases.And abdominal X -ray plain films at the 1 st day after operation showed peritoneal catheter was located in pelvic cavity in 31 cases and lower abdominal cavity in 5 cases.At the 3rd day and 7th day after operation,the numbers of peritoneal catheter located in pelvic cavity were 35 and 39 respectively.Among these patients,a large acute subdural hematoma occurred on the same side of V - P shunt at the 5th day after operation.This patient was discharged with GCS 6 as his family refused decompressive craniectomy.The remaining 39 patients were discharged with average hospital - stay time of 11 ± 4 days after shunt.On follow - up,1 patient developed peritoneal infection one year later.After the infection was controlled,he was changed to ventriculo- atrial (V -A) shunt.There was no shunt- related complication occurred on the others during 1 -24 month follow - up periods.Conclusion V - P shunt through small straight incision under xiphoid could reduce surgical injury,shorten the operating time and obtain good

  14. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing.

    Venkataraman, Pranav; Browd, Samuel R; Lutz, Barry R


    OBJECTIVE The surgical placement of a shunt designed to resolve the brain's impaired ability to drain excess CSF is one of the most common treatments for hydrocephalus. The use of a dynamic testing platform is an important part of shunt testing that can faithfully reproduce the physiological environment of the implanted shunts. METHODS A simulation-based framework that serves as a proof of concept for enabling the application of virtual intracranial pressure (ICP) and CSF models to a physical shunt-testing system was engineered. This was achieved by designing hardware and software that enabled the application of dynamic model-driven inlet and outlet pressures to a shunt and the subsequent measurement of the resulting drainage rate. RESULTS A set of common physiological scenarios was simulated, including oscillations in ICP due to respiratory and cardiac cycles, changes in baseline ICP due to changes in patient posture, and transient ICP spikes caused by activities such as exercise, coughing, sneezing, and the Valsalva maneuver. The behavior of the Strata valve under a few of these physiological conditions is also demonstrated. CONCLUSIONS Testing shunts with dynamic ICP and CSF simulations can facilitate the optimization of shunts to be more failure resistant and better suited to patient physiology.

  15. Indication for shunt operation of normal pressure hydrocephalus. Combined assessment of infusion test and dynamic CT scan

    Jinnai, Takahiro; Nagao, Seigo [Kagawa Medical Univ., Miki (Japan); Kuyama, Hideyuki


    Normal pressure hydrocephalus (NPH) is one of the diseases that causes a neuro-surgically treatable form of dementia. Although patients with NPH can be treated with shunt operation, reliable indications for the surgery are not yet established. In this study, 20 NPH patients diagnosed by clinical symptoms were subjected to combined assessment by infusion test and dynamic CT scan, a useful diagnostic tool to select a shunt responsive cases. Patients were evaluated by measuring sequential changes in the density of the periventricular lucency (PVL) using dynamic CT scan and continuous lumbar subdural pressure monitoring during an infusion manometric test at a rate of 0.8 ml/min for 30 min. The average lumbar subdural pressure during infusion manometric test in the shunt responsive group was 18.4{+-}5.8 mmHg, which was significantly higher than that in the shunt non-responsive group which was 10.0{+-}4.0 mmHg (p<0.01). The relative changes in PVL density in the dynamic CT was also significantly higher in the shunt responsive group (0.99{+-}0.61 HU) compared to the shunt non-responsive group (0.15{+-}0.32) (p<0.01). Dynamic CT scan with infusion manometric test is useful in the selection of patients with NPH who are likely to respond to shunt surgery. (author)

  16. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt

    Pickard John D


    Full Text Available Abstract Background The Polaris valve is a newly released hydrocephalus shunt that is designed to drain cerebrospinal fluid (CSF from the brain ventricles or lumbar CSF space. The aim of this study was to bench test the properties of the Polaris shunt, independently of the manufacturer. Methods The Polaris Valve is a ball-on-spring valve, which can be adjusted magnetically in vivo. A special mechanism is incorporated to prevent accidental re-adjustment by an external magnetic field. The performance and hydrodynamic properties of the valve were evaluated in the UK Shunt Evaluation Laboratory, Cambridge, UK. Results The three shunts tested showed good mechanical durability over the 3-month period of testing, and a stable hydrodynamic performance over 45 days. The pressure-flow performance curves, operating, opening and closing pressures were stable. The drainage rate of the shunt increased when a negative outlet pressure (siphoning was applied. The hydrodynamic parameters fell within the limits specified by the manufacturer and changed according to the five programmed performance levels. Hydrodynamic resistance was dependant on operating pressure, changing from low values of 1.6 mmHg/ml/min at the lowest level to 11.2 mmHg/ml/min at the highest performance level. External programming proved to be easy and reliable. Even very strong magnetic fields (3 Tesla were not able to change the programming of the valve. However, distortion of magnetic resonance images was present. Conclusion The Polaris Valve is a reliable, adjustable valve. Unlike other adjustable valves (except the Miethke ProGAV valve, the Polaris cannot be accidentally re-adjusted by an external magnetic field.

  17. Risk Factors for Tube Shunt Exposure: A Matched Case-Control Study

    Michael S. Koval


    Full Text Available Purpose. To evaluate potential risk factors for developing tube shunt exposure in glaucoma patients. Patients and Methods. Forty-one cases from 41 patients that had tube shunt exposure from 1996 to 2005 were identified from the Robert Cizik Eye Clinic and Bascom Palmer Eye Institute. Each case was matched with 2 controls of the same gender and with tube shunts implanted within 6 months of the index case. Conditional logistic regression was used to determine risk factors. Results. The study cohort includes a total of 121 eyes from 121 patients. The mean age was 63.6 ± 19.7 years, ranging from 1 to 96 years. The average time to exposure was 19.29 ± 23.75 months (range 0.36–85.74 months. Risk factors associated with tube exposure were Hispanic ethnicity (P=0.0115; OR = 3.6; 95% CI, 1.3–9.7, neovascular glaucoma (P=0.0064; OR = 28.5; 95% CI, 2.6–316.9, previous trabeculectomy (P=0.0070; OR = 5.3; 95% CI, 1.6–17.7, and combined surgery (P=0.0381; OR = 3.7; 95% CI, 1.1–12.7. Conclusions. Hispanic ethnicity, neovascular glaucoma, previous trabeculectomy, and combined surgery were identified as potential risk factors for tube shunt exposure. These potential risk factors should be considered when determining the indication for performing tube shunt implantation and the frequency of long-term followup.

  18. Preservation of portal pressure improves growth and metabolic profile in the male portacaval-shunted rat.

    Dasarathy, Srinivasan; Mullen, Kevin D; Conjeevaram, Hari S; Kaminsky-Russ, Kristine; Wills, Laurie A; McCullough, Arthur J


    The portacaval anastomosis (PCA) rat model and human cirrhosis have many metabolic and nutritional abnormalities in common, such as growth retardation, hepatic and gonadal atrophy, and hyperammonemia. The severity of these abnormalities is variable and may be related to a number of factors, including portal pressure, portosystemic shunting, dietary intake, and how efficiently food is used. Therefore, this rat model was used to study these variables with the intent of gaining insights for improving the management of portal hypertension and malnutrition in human cirrhosis. A nonsuture end-to-side PCA (N = 100) or sham surgery (N = 71) was performed in 100 male rats. Four weeks after surgery, body and organ weights, food intake, serum ammonia, and serum amino acids were measured at death. In a subgroup of rats, (sham 7; PCA 34) portal venous pressure, degree of portosystemic shunting, and organ and body weights were obtained at death. Growth, liver weight, and testes weight were decreased, ammonia levels were higher, and the ratios of branched chain to aromatic amino acid (BCAA/AAA) were lower in the PCA group compared to the sham animals (P spleen weights correlated with portal pressure (P = 0.01), the PCA animals were then divided into those with preserved and those with low portal pressures based on spleen weight. The PCA group with preserved portal pressure had better growth, larger livers and testes, lower serum ammonia, and higher BCAA/AAA levels than the PCA group with low portal pressure; improvements associated with normal amounts of food intake and better food efficiency than the low pressure animals (P < 0.05 or better). Sham animals had no portosystemic shunting, while 100% shunting occurred in both PCA groups regardless of the portal pressure. In conclusion, preservation of portal pressure after portacaval anastomosis provides metabolic and nutritional benefits, which are independent of portosystemic shunting and associated with normal dietary intake and

  19. Retrograde migration and subcutaneous coiling of the peritoneal catheter of a ventriculoperitoneal shunt in a cat

    Sinead E Bennett


    Full Text Available Case summary Ventriculoperitoneal shunt placement is the most commonly utilised surgical treatment for hydrocephalus in human and veterinary patients. Migration of the peritoneal catheter is an uncommon but well-documented complication in people, usually occurring within the first 3 months postoperatively, although only a single feline case report exists. A ventriculoperitoneal shunt was placed in a domestic shorthair cat, aged 4 years and 10 months, following a diagnosis, with MRI, of unilateral, non-communicating hydrocephalus. Diarrhoea, increased vocalisation and pruritus were reported within the first 3 months postoperatively. A shunt-associated seroma developed, which was aspirated under ultrasound guidance. Within 3 days, the entire peritoneal catheter was subcutaneously coiled at the level of the seroma. The peritoneal catheter was replaced within the abdomen via a new subcutaneous tunnel. No further complications had occurred 24 months following revision surgery. Relevance and novel information This is the second report describing peritoneal catheter migration in a cat. Repetitive head and neck movements during self-grooming, raised intra-abdominal pressure secondary to vocalisation and tenesmus, and negative pressure exerted during seroma aspiration may have contributed to ventriculoperitoneal shunt migration. Excessive loose skin and increased activity may further increase the risk of migration in cats. Diagnostic imaging should be offered prior to and following aspiration of shunt-associated swellings, and minimal negative pressure should be exerted. Attempts to reduce the frequency of postoperative self-grooming, prevention and prompt treatment of conditions predisposing to raised intra-abdominal pressure and moderate exercise restriction, particularly within the first 3 months, may help reduce the risk of peritoneal catheter migration.

  20. Staging of portal hypertension and portosystemic shunts using dynamic nuclear medicine investigations

    Dragoteanu, Mircea; Balea, Ioan A; Dina, Liliana A; Piglesan, Cecilia D; Grigorescu, Ioana; Tamas, Stefan; Cotul, Sabin O


    AIM: To explore portal hypertension and portosystemic shunts and to stage chronic liver disease (CLD) based on the pathophysiology of portal hemodynamics. METHODS: Per-rectal portal scintigraphy (PRPS) was performed on 312 patients with CLD and liver angioscintigraphy (LAS) on 231 of them. The control group included 25 healthy subjects. We developed a new model of PRPS interpretation by introducing two new parameters, the liver transit time (LTT) and the circulation time between right heart and liver (RHLT). LTT for each lobe was used to evaluate the early portal hypertension. RHLT is useful in cirrhosis to detect liver areas missing portal inflow. We calculated the classical per-rectal portal shunt index (PRSI) at PRPS and the hepatic perfusion index (HPI) at LAS. RESULTS: The normal LTT value was 24 ± 1 s. Abnormal LTT had PPV = 100% for CLD. Twenty-seven non-cirrhotic patients had LTT increased up to 35 s (median 27 s). RHLT (42 ± 1 s) was not related to liver disease. Cirrhosis could be excluded in all patients with PRSI 30% had PPV = 100% for cirrhosis. Based on PRPS and LAS we propose the classification of CLD in 5 hemodynamic stages. Stage 0 is normal (LTT = 24 s, PRSI 30%. RHLT and HPI were used to subtype stage 4. In our study stage 0 had NPV = 100% for CLD, stage 1 had PPV = 100% for non-cirrhotic CLD, stages 2 and 3 represented the transition from chronic hepatitis to cirrhosis, stage 4 had PPV = 100% for cirrhosis. CONCLUSION: LTT allows the detection of early portal hypertension and of opening of transhepatic shunts. PRSI is useful in CLD with extrahepatic portosystemic shunts. Our hemodynamic model stages the evolution of portal hypertension and portosystemic shunts. It may be of use in the selection of patients for interferon therapy. PMID:18609707

  1. 发电机纵联差动保护误动原因分析%Cause Analysis of the Malfunction of the Longitudinal Differential Protection of a Generator

    王安甫; 徐明


    通过分析一起发电机纵差保护误动的原因,对差动保护两侧电流互感器的特性、差动回路阻抗进行比较,并全面复核保护定值,以避免在区外故障时,差动回路中产生不平衡电流,发生保护误动作。%Based on the cause analysis of the malfunction of the longitudinal differential protection of a generator,this essay compares the featm's and the differential circuit impedances between the two current transformers of the dif ferential protection. Besides, it also rechecks the fixed value of the protection to avoid protection malfunctions caused by unbalanced current in the differential circuit beyond the relay protection zone.

  2. Acute pancreatitis

    Bo-Guang Fan


    Full Text Available Background : Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims : The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods : We reviewed the English-language literature (Medline addressing pancreatitis. Results : Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions : Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  3. Acute pancreatitis

    Bo-Guang Fan


    Full Text Available Background: Acute pancreatitis continues to be a serious illness, and the patients with acute pancreatitis are at risk to develop different complications from ongoing pancreatic inflammation. Aims: The present review is to highlight the classification, treatment and prognosis of acute pancreatitis. Material & Methods: We reviewed the English-language literature (Medline addressing pancreatitis. Results: Acute pancreatitis is frequently caused by gallstone disease or excess alcohol ingestion. There are a number of important issues regarding clinical highlights in the classification, treatment and prognosis of acute pancreatitis, and treatment options for complications of acute pancreatitis including pancreatic pseudocysts. Conclusions: Multidisciplinary approach should be used for the management of the patient with acute pancreatitis.

  4. [Results of the surgical treatment of acute thrombosis of the major arteries of the limbs].

    Ovchinnikov, V A; Vereshchagin, N A; Shavin, V V; Parakhoniak, N V


    An analysis of the surgical treatment of acute arterial trombosis of the extremities in 86 patients is presented. The causes of thrombosis were mainly obliterating atherosclerosis, artery trauma and postembolic occlusion. Best results of reconstructive operations were obtained in patients with postembolic occlusion of the arteries and their posttraumatic trombosis, worst results - in obliterating atherosclerosis. Thrombendarterectomy and autovenous shunts and prostheses were found to be the mos effective reconstructive operations.

  5. Malfunctioning DNA damage response (DDR) leads to the degeneration of nigro-striatal pathway in mouse brain.

    Kirshner, Michal; Galron, Ronit; Frenkel, Dan; Mandelbaum, Gil; Shiloh, Yosef; Wang, Zhao-Qi; Barzilai, Ari


    Pronounced neuropathology is a feature of ataxia-telangiectasia (A-T) and Nijmegen breakage syndrome (NBS), which are both genomic instability syndromes. The Nbs1 protein, which is defective in NBS, is a component of the Mre11/RAD50/NBS1 (MRN) complex. This complex plays a major role in the early phase of the cellular response to double strand breaks (DSBs) in the DNA. Among others, MRN is required for timely activation of the protein kinase ATM (A-T mutated), which is disrupted in patients with A-T. Earlier reports show that Atm-deficient mice exhibit severe degeneration of tyrosine hydroxylase (TH)-positive dopaminergic nigro-striatal neurons and their terminals in the striatum. This cell loss is accompanied by a large reduction in immunoreactivity for the dopamine transporter protein (DAT) in the striatum. To test whether Nbs1 inactivation also affects the integrity of the nigro-striatal pathway, we examined this pathway in a murine model with conditional inactivation of the Nbs1 gene in central nervous system (Nbs1-CNS-Δ). We report that this model has a reduction in TH-positive cells in the substantia nigra. This phenomenon was seen at very early age, while Atm-/- mice showed a progressive age-dependent reduction. Furthermore, we observed an age-dependent increase in the level of TH in the striatum of Atm-/- and Nbs1-CNS-Δ mice. In addition to the altered expression of TH, we also found a reduction of DAT in the striatum of both Atm-/- and Nbs1-CNS-Δ mice at 60 days of age. Finally, microglial recruitment and alterations in the levels of various neurotrophic factors were also observed. These results indicate that malfunctioning DNA damage response severely affects the integrity of the nigro-striatal pathway and suggest a new neurodegenerative pathway in Parkinsonian syndromes.

  6. Acute two-compartment low pressure hydrocephalus--a case report.

    Preuß, M; Evangelou, P; Hirsch, W; Reiss-Zimmermann, M; Fischer, L; Merkenschlager, A; Kieß, W; Siekmeyer, M; Meixensberger, J; Nestler, U


    A case of an 8-year-old-boy with shunt-dependent occlusive hydrocephalus after resection of a cerebellar medulloblastoma is presented, who experienced repeated episodes of severe neurologic deterioration with signs and symptoms of raised intracranial pressure after spinal tapping. However, intracranial pressure was recorded within low ranges, only up to the opening pressure of the implanted adjustable shunt valve. Multiple shunt revisions were performed, until the condition was recognized as acute normal pressure hydrocephalus. Either enforced recumbency and downadjustment of the valve system to 0 cm H(2)O alone or external ventricular drainage seems to be successful to resolve the critical condition, depending on severity of the symptoms. The case illustrates that acute pathologic enlargement of the ventricular system is not always associated with increased intracranial pressure, even when typical signs and symptoms are present. The very rare entity of acute normal pressure hydrocephalus by two separated compartments is postulated based on the pulsatile vector force theory of brain water circulation.

  7. Differential shunting in the diagnosis of patent ductus arteriosus with Eisenmenger physiology by radionuclide angiography. [/sup 99m/Te-pertechnetate; (sup 99m/Te-MAA; aorta-pulmanary artery shunts

    Thomas, J.L.; Scherer, J.; Kahl, F.R.; Watson, N.; Cowan, R.


    Radionuclide angiography and static whole-body imaging performed with technetium-99m-labeled particulates can clearly demonstrate differential shunting in patients with patent ductus arteriosus (PDA) with Eisenmenger physiology. The anatomic arterial relationships in this condition which direct deoxygenated blood into the lower body (differential cyanosis) produce specific radionuclide images characterized by differential shunting of the technetium-99m-labeled particulates into the abdomen and lower extremity.

  8. Staging of portal hypertension and portosystemic shunts using dynamic nuclear medicine investigations

    Mircea Dragoteanu; Ioan A Balea; Liliana A Dina; Cecilia D Piglesan; Ioana Grigorescu; Stefan Tamas; Sabin O Cotul


    AIM: To explore portal hypertension and portosystemic shunts and to stage chronic liver disease (CLD)based on the pathophysiology of portal hemodynamics.METHODS: Per-rectal portal scintigraphy (PRPS) was performed on 312 patients with CLD and liver angioscintigraphy (LAS) on 231 of them.The control group included 25 healthy subjects.We developed a new model of PRPS interpretation by introducing two new parameters,the liver transit time (LIT) and the circulation time between right heart and liver (RHLT).LTT for each lobe was used to evaluate the early portal hypertension.RHLT is useful in cirrhosis to detect liver areas missing portal inflow.We calculated the classical per-rectal portal shunt index (PRSI) at PRPS and the hepatic perfusion index (HPI) at LAS.RESULTS: The normal LTT value was 24 ±1 s.Abnormal LTT had PPV = 100% for CLD.Twenty-seven noncirrhotic patients had L-IT increased up to 35 s (median 27 s).RHLT (42 ±1 s) was not related to liver disease.Cirrhosis could be excluded in all patients with PRSI< 5% (P < 0.01).PRSI > 30% had PPV = 100% for cirrhosis.Based on PRPS and LAS we propose the classification of CLD in 5 hemodynamic stages.Stage 0 is normal (LIT = 24 s,PRSI < 5%).In stage 1,LIT is increased,while PRSI remains normal.In stage 2,LIT is decreased between 16 s and 23 s,whereas PRSI is increased between 5% and 10%.In stage 3,PRSI is increased to 10%-30%,and LTT becomes undetectable by PRPS due to the portosystemic shunts.Stage 4 includes the patients with PRSI > 30%.RHLT and HPI were used to subtype stage 4.In our study stage 0 had NPV = 100% for CLD,stage 1 had PPV = 100% for non-cirrhotic CLD,stages 2 and 3 represented the transition from chronic hepatitis to cirrhosis,stage 4 had PPV = 100% for cirrhosis.CONCLUSION: LTT allows the detection of early portal hypertension and of opening of transhepatic shunts.PRSI is useful in CLD with extrahepatic portosystemic shunts.Our hemodynamic model stages the evolution of portal hypertension

  9. Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report.

    Chan, Andrew K; Birk, Harjus S; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W


    The Optune® transducer array (Novocure Ltd., Haifa, Israel) is an FDA-approved noninvasive regional therapy that aims to inhibit the growth of glioblastoma multiforme (GBM) cells via utilization of alternating electric fields. Some patients with GBM may develop hydrocephalus and benefit from subsequent shunt placement, but special attention must be paid to patients in whom programmable valves are utilized, given the potential effect of the magnetic fields on valve settings. We present the first case report illustrating the stability of programmable shunt valve settings in a neurosurgical patient undergoing therapy with the Optune device. In this study, shunt valve settings were stable over a period of five days despite Optune therapy. This is reassuring for patients with GBM who require simultaneous treatment with both the Optune device and a programmable shunt system.

  10. An efficient method for monitoring the shunts in silicon solar cells during fabrication processes with infrared imaging

    Zhang Lucheng; Xu Xinxiang; Yang Zhuojian; Sun Xiaopu; Xu Hongyun; Liu Haobin; Shen Hui


    , and energy dispersive X-ray spectroscopy. Approaches for diminishing shunts are presented. The methods are beneficial for the optimization of the cell fabrication processes and the improvement of the cell performances.

  11. Acute cholecystitis

    Halpin, Valerie


    Acute cholecystitis causes unremitting right upper quadrant pain, anorexia, nausea, vomiting, and fever, and if untreated can lead to perforations, abscess formation, or fistulae. About 95% of people with acute cholecystitis have gallstones.It is thought that blockage of the cystic duct by a gallstone or local inflammation can lead to acute cholecystitis, but we don't know whether bacterial infection is also necessary.

  12. Usable Analysis on Car Bearing Malfunction Diagnosis in Means of Oil-analysis%油脂分析法用于车辆轴承故障诊断的可行性分析



    pointing-out problems on analysis and treating bearing malfunction diagnosis, stating usability of checking and verdicting bearing malfunction diagnosis.%针对目前列检等部门在分析、处理轴承故障方面存在的问题,论述了油样分析法用于检测、判断轴承故障的可行性。

  13. Melatonin mitigates mitochondrial malfunction.

    León, Josefa; Acuña-Castroviejo, Darío; Escames, Germane; Tan, Dun-Xian; Reiter, Russel J


    Melatonin, or N-acetyl-5-methoxytryptamine, is a compound derived from tryptophan that is found in all organisms from unicells to vertebrates. This indoleamine may act as a protective agent in disease conditions such as Parkinson's, Alzheimer's, aging, sepsis and other disorders including ischemia/reperfusion. In addition, melatonin has been proposed as a drug for the treatment of cancer. These disorders have in common a dysfunction of the apoptotic program. Thus, while defects which reduce apoptotic processes can exaggerate cancer, neurodegenerative disorders and ischemic conditions are made worse by enhanced apoptosis. The mechanism by which melatonin controls cell death is not entirely known. Recently, mitochondria, which are implicated in the intrinsic pathway of apoptosis, have been identified as a target for melatonin actions. It is known that melatonin scavenges oxygen and nitrogen-based reactants generated in mitochondria. This limits the loss of the intramitochondrial glutathione and lowers mitochondrial protein damage, improving electron transport chain (ETC) activity and reducing mtDNA damage. Melatonin also increases the activity of the complex I and complex IV of the ETC, thereby improving mitochondrial respiration and increasing ATP synthesis under normal and stressful conditions. These effects reflect the ability of melatonin to reduce the harmful reduction in the mitochondrial membrane potential that may trigger mitochondrial transition pore (MTP) opening and the apoptotic cascade. In addition, a reported direct action of melatonin in the control of currents through the MTP opens a new perspective in the understanding of the regulation of apoptotic cell death by the indoleamine.

  14. Creation of an iliac arteriovenous shunt lowers blood pressure in chronic obstructive pulmonary disease patients with hypertension.

    Faul, John


    Vasodilators are used with caution in patients with chronic obstructive pulmonary disease (COPD). We have developed a device for percutaneous arteriovenous shunt creation in the iliac region to increase cardiac output and oxygen delivery for patients with COPD. Although this device does not cause significant blood pressure changes in normotensive patients with COPD, we hypothesized that arteriovenous shunt creation might cause vasodilator effects in hypertensive patients because of a reduction in vascular resistance.


    I. A. Porshennikov


    Full Text Available We present our first experience gained in use of polytetrafluoroethylene carbon-coated grafts for partial portosystemic shunting in three cirrhotic patients. The results obtained indicate that these grafts in mesocaval position can function as a long-term «bridge» to hepatic transplantation in patients with uncontrolled gastroesophageal varices. The different options of portal hypertension treatment and the current role of shunting procedures in the era of liver transplantation are discussed in short literature review. 

  16. Unsatisfactory outcomes of prolonged ischemic priapism without early surgical shunts: our clinical experience and a review of the literature

    Da-Chao Zheng; Hai-Jun Yao; Ke Zhang; Ming-Xi Xu; Qi Chen; Yan-Bo Chen; Zhi-Kang Cai; Mu-Jun Lu; Zhong Wang


    Ischemic priapism is a rare occurrence which can cause severe erectile dysfunction (ED) without timely treatment.This retrospective study reports our experience in treating prolonged ischemic priapism and proposes our further considerations.In this paper,a total of nine patients with prolonged ischemic priapism underwent one to three types of surgical shunts,including nine Winter shunts,two AI-Ghorab shunts and one Grayhack shunt.During the follow-up visit (after a mean of 21.11 months),all patients' postoperative characters were recorded,except one patient lost for death.Six postoperative patients accepted a 25-mg oral administration of sildenafil citrate.The erectile function of the patients was evaluated by their postoperative 5-item version of International Index of Erectile Function Questionnaire (IIEF-5),which were later compared with their premorbid scores.All patients had complete resolutions,and none relapsed.The resolution rate was 100%.Seven patients were resolved with Winter shunts,one with an Al-Ghorab shunt and one with a Grayhack shunt.The mean hospital stay was 8.22 days.There was only one urethral fistula,and the incidence of postoperative ED was 66.67%.Four patients with more than a 72-h duration of priapism had no response to the long-term phosphodiesterase type 5 (PDE-5) inhibitor treatment.These results suggest that surgical shunts are an efficient approach to make the penis flaccid after prolonged priapism.However,the severe ED caused by prolonged duration is irreversible,and long-term PDE-5 inhibitor treatments are ineffective.Thus,we recommend early penile prosthesis surgeries for these patients.

  17. Field Experiments on 10 kV Switching Shunt Capacitor Banks Using Ordinary and Phase-Controlled Vacuum Circuit Breakers

    Wenxia Sima


    Full Text Available During the switching on/off of shunt capacitor banks in substations, vacuum circuit breakers (VCBs are required to switch off or to switch on the capacitive current. Therefore, the VCBs have to be operated under a harsh condition to ensure the reliability of the equipment. This study presents a complete comparison study of ordinary and phase-controlled VCBs on switching 10 kV shunt capacitor banks. An analytical analysis for switching 10 kV shunt capacitor banks is presented on the basis of a reduced circuit with an ungrounded neutral. A phase selection strategy for VCBs to switch 10 kV shunt capacitor banks is proposed. Switching on current waveforms and switching off overvoltage waveforms with, and without, phase selection were measured and discussed by field experiments in a 110 kV substation in Chongqing, China. Results show that the operation of phase-controlled VCBs for 10 kV switching shunt capacitor banks is stable, and phase-controlled VCBs can be used to implement the 10 kV switching on/off shunt capacitor banks to limit the transient overvoltage and overcurrent. The values of overvoltage and inrush current using phase-controlled VCBs are all below those with ordinary VCBs.

  18. Armored brain in patients with hydrocephalus after shunt surgery: review of the literatures.

    Taha, Mahmoud M


    Armored brain or chronic calcified subdural hematoma is a rare complication of cerebrospinal fluid diversion with few cases reported in the literature. Seventeen patients with this pathology have been published. A complete review of the literatures regarding this topic has been collected and discussed. The author also presents a 12- year old boy with triventricular hydrocephalus who had undergone ventriculoperitoneal medium pressure shunt system since birth. The patient presented to our clinic with a 2-year history of seizures. The patient was conscious and without neurological deficits on examination. Computed tomography of the brain showed bilateral high density mass with surface calcification. X ray skull and MRI confirmed the calcified subdural hematoma bilaterally. We preferred conservative treatment and the patient continued his antiepileptic treatment. At one year follow up, the patient had the same neurological state. The case highlights the importance of frequent follow up CT brain after shunt surgery.

  19. Parkinsonian Symptomatology May Correlate with CT Findings before and after Shunting in Idiopathic Normal Pressure Hydrocephalus

    Mitsuaki Ishii


    Full Text Available We aimed to investigate the characteristics of Parkinsonian features assessed by the unified Parkinson's disease rating scale (UPDRS and determine their correlations with the computed tomography (CT findings in patients with idiopathic normal pressure hydrocephalus (iNPH. The total score and the scores for arising from chair, gait, postural stability, and body hypokinesia in the motor examination section of UPDRS were significantly improved after shunt operations. Stepwise multiple regression analysis revealed that postural stability was the determinant of the gait domain score of the iNPH grading scale. The canonical correlation analysis between the CT findings and the shunt-responsive Parkinsonian features indicated that Evans index rather than midbrain diameters had a large influence on the postural stability. Thus, the pathophysiology of postural instability as a cardinal feature of gait disturbance may be associated with impaired frontal projections close to the frontal horns of the lateral ventricles in the iNPH patients.

  20. Simulation Research of Transient Over-voltage on High-voltage Shunt Capacitor Banks

    HU Quan-wei; ZHOU Xing-xing; SI Wen-rong; ZHANG Yang; LI Jur-hao; LI Yan-ming


    With the development of power systems,a large number of shunt capacitors are used to improve power quality in the distribution network.The shunt capacitor banks are operated much frequently,as a result,the capacitor banks will bear large numbers of over-voltage inevitably.If the over-voltage exceeds certain amplitude,the capacitor will be damaged.This paper aims at the capacitor banks in the 35 kV side of Shanghai Xu-xing 500 kV substation,and applies ATP-EMTP to simulate the over-voltages generated by operating the switches under different angles of the source.Finally,according to the results of simulation and theoretical analysis,a best choice (i.e.angles of the source) to switch on capacitor banks is proposed.In this case the over-voltage on the capacitor will be limited to lowest.

  1. Thoraco-amniotic shunting for fetal pleural effusion--a case series.

    Walsh, J


    Fetal pleural effusion is a rare occurrence, with an incidence of 1 per 10-15,000 pregnancies. The prognosis is related to the underlying cause and is often poor. There is increasing evidence that in utero therapy with thoraco-amniotic shunting improves prognosis by allowing lung expansion thereby preventing hydrops and pulmonary hypoplasia. This is a review of all cases of fetal pleural effusion managed over an eight year period the National Maternity Hospital Dublin. Over the nine year period there were 21 cases of fetal pleural effusion giving an overall incidence of 1 per 9281 deliveries. Of these, 15 underwent thoraco-amniotic shunting. There were associated anomalies diagnosed in 5 (33%) of cases. The overall survival in our cohort was 53%. The presence of hydrops was a poor prognostic factor, with survival in cases with hydrops of 33% (3\\/9) compared to 83% (5\\/6) in those cases without associated hydrops.

  2. Laparoscopic umbilical hernia repair in a cirrhotic patient with a peritoneovenous shunt.

    Umemura, Akira; Suto, Takayuki; Sasaki, Akira; Fujita, Tomohiro; Endo, Fumitaka; Wakabayashi, Go


    A 62-year-old Japanese woman who had developed massive cirrhotic ascites was referred to our hospital for a peritoneovenous shunt implant. However, CT examination revealed an umbilical hernia that had not been observed before the peritoneovenous shunt was implanted. We decided to perform laparoscopic umbilical hernia repair to keep carbon dioxide from flowing backward into the central circulatory system. We first clamped the catheter and set the upper limit of the pneumoperitoneum pressure to 6 mmHg. The central venous pressure was also measured simultaneously. Mesh was then applied over the hernia and fixed by the double-crown technique. Finally, 1000-mL physiological saline was infused into the abdominal cavity while the pneumoperitoneum was slowly released. In this case, we safely performed laparoscopic umbilical hernia repair while making some alterations, specifically catheter clamping, reducing pneumoperitoneum pressure, monitoring central venous pressure, and infusing physiological saline.

  3. Reduction of Switching Surge by Controlled Shunt Reactor Switching of Gas Circuit Breaker

    Kohyama, Haruhiko; Ito, Hiroki; Asai, Jun; Hidaka, Mikio; Yonezawa, Takashi

    Controlled switching system (CSS) with a 204kV gas circuit breaker (GCB) demonstrates to reduce an inrush current and to eliminate re-ignitions in shunt reactor switching. Target closing and opening instants for controlled switching are determined by the electrical and mechanical characteristics of GCB. Idle time dependence of the operating time, which gives a sufficient impact on controlling accuracy, is evaluated and successfully compensated by synchronous switching controller (SSC). Field operation of CSS for a year shows an effective suppression of inrush current on closing and prevention of re-ignitions on opening of shunt reactor. The operations also proved that the CSS has a satisfactory performance for electro-magnetic disturbance imposed in practical field.

  4. Analytical theory of DC SQUID with a resistively shunted inductance driven by thermal noises

    Lü Hai-Feng; Gu Jiao; Huang Xin-Tang


    An analytical expression for the stationary probability distribution of the DC superconducting quantum interference device (SQUID) with a resistively shunted inductance driven by thermal noise is derived from the two-dimensional Fokker-Planck equation. The effects on the SQUID characteristics subject to a large thermal fluctuation with a noise parpameter г>0.20 are discussed by taking into account the thermal noise in the accuracy of numerical simulation. This theory is valid for a reduced inductance β≤1. The analytical formulae for the SQUID characteristics, e.g. the circulating current, the average voltage and the voltage modulation, are obtained and discussed. The theory shows that the voltage modulation increases with the shunted inductance more efficiently for a large inductance parameterβ and small fluctuation parpameterг.

  5. State-variable control of shunt FACTS devices using phasor measurements

    Machowski, J. [Warsaw University of Technology, Instytut Elektroenergetyki, Koszykowa 75, 00-662 Warszawa (Poland); Bialek, J.W. [University of Edinburgh, School of Engineering and Electronics, King' s Buildings, Mayfield Road, Edinburgh EH9 3JL (United Kingdom)


    This paper addresses the problem of state-variable stabilizing control of power system using shunt FACTS devices. This stabilizing control is activated in the transient state of a power system and is supplementary with respect to the main steady-state control of a FACTS device. Stabilizing control laws have been derived for a non-linear multi-machine system model using direct Lyapunov method with the aim to maximize the rate of energy dissipation during power swings and therefore maximization of damping. The proposed control strategy is executed by a non-linear multi-loop controller with rotor angles and speed deviations of synchronous generators used as the input signals. The input signals, obtained from a phasor measurement system, are necessary only from a small area around the controlled shunt FACTS device. Validity of the proposed state-variable control has been confirmed by computer simulation for a small multi-machine test system. (author)

  6. Design and Implementation of Takagi-Sugeno Fuzzy Logic Controller for Shunt Compensator

    Singh, Alka; Badoni, Manoj


    This paper describes the application of Takagi-Sugeno (TS) type fuzzy logic controller to a three-phase shunt compensator in power distribution system. The shunt compensator is used for power quality improvement and has the ability to provide reactive power compensation, reduce the level of harmonics in supply currents, power factor correction and load balancing. Additionally, it can also be used to regulate voltage at the point of common coupling (PCC). The paper discusses the design of TS fuzzy logic controller and its implementation based on only four rules. The smaller number of rules makes it suitable for experimental verification as compared to Mamdani fuzzy controller. A small laboratory prototype of the system is developed and the control algorithm is verified experimentally. The TS fuzzy controller is compared with the proportional integral based industrial controller and their performance is compared under a wide variation of dynamic load changes.

  7. Effect of Circuit Breaker Shunt Resistance on Chaotic Ferroresonance in Voltage Transformer



    Full Text Available Ferroresonance or nonlinear resonance is a complex electrical phenomenon, which may cause over voltages and over currents in the electrical power system which endangers the system reliability and continuous safe operating. This paper studies the effect of circuit breaker shunt resistance on the control of chaotic ferroresonance in a voltage transformer. It is expected that this resistance generally can cause ferroresonance dropout. For confirmation this aspect Simulation has been done on a one phase voltage transformer rated 100VA, 275kV. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial with q=7. The simulation results reveal that considering the shunt resistance on the circuit breaker, exhibits a great mitigating effect on ferroresonance over voltages. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos along with ferroresonance voltages has been obtained and presented.

  8. Congenital Extrahepatic Portosystemic Shunts: Spectrum of Findings on Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

    Pankaj Gupta


    Full Text Available Congenital extrahepatic portosystemic shunt (CEPS is a rare disorder characterised by partial or complete diversion of portomesenteric blood into systemic veins via congenital shunts. Type I is characterised by complete lack of intrahepatic portal venous blood flow due to an end to side fistula between main portal vein and the inferior vena cava. Type II on the other hand is characterised by partial preservation of portal blood supply to liver and side to side fistula between main portal vein or its branches and mesenteric, splenic, gastric, and systemic veins. The presentation of these patients is variable. Focal liver lesions, most commonly nodular regenerative hyperplasia, are an important clue to the underlying condition. This pictorial essay covers imaging characteristics in abdominopelvic region.

  9. Hepatic Encephalopathy due to Congenital Multiple Intrahepatic Portosystemic Venous Shunts Successfully Treated by Percutaneous Transhepatic Obliteration

    Shinsuke Takenaga


    Full Text Available Hepatic encephalopathy due to intrahepatic portosystemic venous shunts (IPSVS in a non-cirrhotic condition is rare. Here we report a rare case of a patient with congenital multiple IPSVS successfully treated by percutaneous transhepatic obliteration. The patient was a 67-year-old woman who presented to our hospital with progressive episodes of consciousness disorder and vomiting. Laboratory tests revealed hyperammonemia (192.0 μg/dL, and computed tomography revealed multiple IPSVS in both lobes. There was no evidence of underlying liver disease or hepatic trauma. Transcatheter embolization for IPSVS was performed because conservative therapy was not sufficiently effective. After endovascular shunt closure, hepatic encephalopathy improved. The serum ammonia level normalized during the 5-year follow-up period. Thus, transcatheter embolization may be an effective therapy for patients with symptomatic and refractory IPSVS. Careful follow-up is necessary for portal hypertension-related complications after transcatheter embolization for IPSVS.

  10. Application of VSC-HVDC with Shunt Connected SMES for Compensation of Power Fluctuation

    Linn, Zarchi; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi

    This paper describes the application of VSC-HVDC (High Voltage DC Transmission using Voltage Source Converter) with shunt connected SMES (Superconducting Magnetic Energy Storage) for compensation of power fluctuation caused by fluctuating power source such as photovoltaics and wind turbines. The objectives of this proposed system is to smooth out fluctuating power in one terminal side of HVDC in order to avoid causing power system instability and frequency deviation by absorbing or providing power according to the system requirement while another terminal side power is fluctuated. The shunt connected SMES charges and discharges the energy to and from the dc side and it compensates required power of fluctuation to obtain constant power flow in one terminal side of VSC-HVDC system. This system configuration has ability for power system stabilization in the case of power fluctuation from natural energy source. PSCAD/EMTDC simulation is used to evaluate the performance of applied system configuration and control method.

  11. Options Studied for Managing Space Station Solar Array Electrical Hazards for Sequential Shunt Unit Replacement

    Delleur, Ann M.; Kerslake, Thomas W.; Levy, Robert K.


    The U.S. solar array strings on the International Space Station are connected to a sequential shunt unit (SSU). The job of the SSU is to shunt, or short, the excess current from the solar array, such that just enough current is provided downstream to maintain the 160-V bus voltage while meeting the power load demand and recharging the batteries. Should an SSU fail on-orbit, it would be removed and replaced with the on-orbit spare during an astronaut space walk or extravehicular activity (EVA) (see the photograph). However, removing an SSU during an orbit Sun period with input solar array power connectors fully energized could result in substantial hardware damage and/or safety risk to the EVA astronaut. The open-circuit voltage of cold solar-array strings can exceed 320 V, and warm solar-array strings could feed a short circuit with a total current level exceeding 240 A.

  12. Radiological findings in complications of CSF-draining shunts in infantile hydrocephalus

    Faerber, D.


    A CSF-draining system functioning free form disturbances is the precondition for age-appropriate further development of the brain in the treatment of infantile hydrocephalus. Shunt dysfuncion may be caused by infection but also by mechanical or functional disturbances with the latter two being summarized under the generic term of 'shunt insufficiency'. Imaging techniques rank first in diagnosis. Plain film X-raying will discover a possible misalignment of the system, a disconnection or a rupture with or without embolization of a valve section. Patency of the system can be verified by valvography using contrast medium or isotopes. CT plays a significant part in the diagnosis of 'hyperdrained' hydrocephalus. In rare cases, pulmonary hyperpressure with cor pulmonale due to chronic micro-embolization of the pulmonary vessels will be a late sequela, even if the position of the distal catheter part is correct.

  13. On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

    Davis, Craig R.; Waldman, Frank A.


    The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries.

  14. Vesico-amniotic shunting for lower urinary tract obstruction in a fetus with VACTERL association.

    Kanasugi, Tomonobu; Kikuchi, Akihiko; Haba, Gen; Sasaki, Yuri; Isurugi, Chizuko; Oyama, Rie; Sugiyama, Toru


    Newborn cases of VACTERL association with lower urinary tract obstruction (LUTO) are rare and there have been no reports on those patients undergoing fetal therapy in English literature. We successfully performed vesico-amniotic shunting in a fetus having LUTO caused by abnormality of the external genitalia at 16 weeks' gestation. Although fetal karyotype was normal 46XY, follow-up fetal ultrasound examinations revealed ventriculomegaly in the brain, a small stomach and a right multicystic dysplastic kidney. MRI at 31 weeks' gestation suggested lobar type holoprosencephaly. Diagnosis of VACTERL association was confirmed postnatally. We consider that vesico-amniotic shunting is indicated for a fetus of VACTERL association with LUTO if the parents wish the procedure after genetic counseling and explanations about the fetal conditions.

  15. Revisiting the surgical creation of volume load by aorto-caval shunt in rats.

    Ocampo, Catherina; Ingram, Paul; Ilbawi, Michel; Arcilla, Rene; Gupta, Madhu


    Cardiac hypertrophy is an early landmark during the clinical course of heart failure, and is an important risk factor for subsequent morbidity and mortality. The hypertrophy response to different types of cardiac overload is distinguished both at the molecular and cellular levels. These changes have been extensively characterized for pressure load hypertrophy; however, similar information for volume load hypertrophy is still needed. This study was undertaken to improve the existing method of producing experimental cardiac volume load. Previous investigators have employed surgical aorto-caval shunt (ACS) as a model for volume load hypertrophy (VO) in rats. The procedure is relatively simple and involves glue to seal the aortic hole after ACS. However, it has several limitations mostly related to the use of glue e.g. poor visualization due to hardening of tissues, imperfect sealing of the puncture site and glue seeping through the aortic hole resulting in shunt occlusion. We have modified the procedure using aortic adventitial suture instead of glue and 18G angiocatheter instead of 16G needle, which eliminated the technical difficulties from the former method. The ACS was visually confirmed at sacrifice, and the VO demonstrated by time-related changes in the heart weight/body weight ratio which increased from 78% at 4 weeks to 87% at 10 weeks and increased liver/body weight ratio by 22% at 10 weeks of post aorto-caval shunt. Cardiac expression of atrial natriuretic peptide (ANF) also demonstrated time-related increase in ANF mRNA (+275% increase at 4 weeks, p < 0.05, and +370% increase at 10 weeks, p < 0.001). This modified technique of aorto-caval shunt offers simpler, reproducible and consistent model for VO hypertrophy in rats.

  16. Microwave absorption and resistively shunted Josephson junctions in high temperature CuO superconductors

    Ramachandran, J.S.; Huang, M.X.; Bhagat, S.M. (Dept. of Physics, Univ. of Maryland, College Park, MD (United States)); Kish, K.; Tyagi, S. (Dept. of Physics and Atmospheric Science, Drexel Univ., Philadelphia, PA (United States))


    We report that the field dependence of the magnetoabsorption (virgin curve) in all pristine granular CuO type (HTSC) superconductors follows a one-parameter expression. This ''universal'' result is combined with previous measurements on field and temperature dependences of microwave absorption in HTSC to demonstrate that a simple model based on resistively shunted Josehpson junctions is adequate to qualitatively account for almost all the observations on powders, pellets, thin films and single crystals. (orig.).

  17. Analysis and Sliding Mode Control of Four-Wire Three-Leg Shunt Active Power Filter

    Farid Hamoudi; Hocine Amimeur


    In this paper, the analysis and the sliding mode control application for a shunt active filter is presented. The active filter is based on a three-leg split-capacitor voltage source inverter which is used to compensate harmonics and unbalance in the phase currents, and therefore to cancel neutral current. The proposed sliding mode control is formulated from the multivariable state model established in dq0 frames. The selection of the sliding mode functions takes in account simultaneously, the...

  18. New control algorithm for shunt active filters, based on self-tuned vector filter

    Perales Esteve, Manuel Ángel; Mora Jiménez, José Luis; Carrasco Solís, Juan Manuel; García Franquelo, Leopoldo


    A new, improved, method for calculating the reference of a shunt active filter is presented. This method lays on a filter, which is able to extract the main component of a vector signal. This filter acts as a Phase-Locked Loop, capturing a particular frequency. The output of this filter is in phase with the frequency isolated, and has its amplitude. Simulation and experimental results confirms the validity of the proposed algorithm.

  19. Ex-PRESS miniature glaucoma shunt in treatment of refractory glaucoma.

    Kovačević, Suzana; Čanović, Samir; Didović, Ana; Kolega, Marija Škara; Bašić, Jadranka Katušić


    Refractory glaucoma in a complicated type of glaucoma of different ethyologies with one same characteristic--intraocular pressure of great resistance to therapy. There are different methods of treatment in such glaucomas, primary surgical options. Ex-PRESS miniature glaucoma shunt implantation was our treatment of choice. In our group of patients we achieved stabile intraocular pressure values in 4 month period of time with no serious or unexpected complications.

  20. Irreversible Electroporation of a Hepatocellular Carcinoma Lesion Adjacent to a Transjugular Intrahepatic Portosystemic Shunt Stent Graft

    Niessen, Christoph; Jung, Ernst Michael; Wohlgemuth, Walter A. [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany); Trabold, Benedikt [Department of Anaesthesia, University Medical Center Regensburg, Regensburg D-93053 (Germany); Haimerl, Michael; Schreyer, Andreas; Stroszczynski, Christian; Wiggermann, Philipp [Department of Radiology, University Medical Center Regensburg, Regensburg D-93053 (Germany)


    We report in a 65-year-old man hepatocellular carcinoma adjacent to a transjugular intrahepatic portosystemic shunt stent-graft which was successfully treated with irreversible electroporation (IRE). IRE is a new non-thermal tissue ablation technique which uses electrical pulses to induce cell necrosis by irreversible membrane poration. IRE proved to be more advantageous in the ablation of perivascular tumor with little injury to the surrounding structures.

  1. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    Le R; Gupta N


    Ryan Le,1 Neeru Gupta1–3 1Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada; 2Ophthalmology and Vision Sciences, Glaucoma Unit, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada; 3Laboratory Medicine and Pathobiology, St. Michael's Hospital, University of Toronto, Toronto, ON, CanadaAbstract: The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension gla...

  2. Asymptomatic Intrahepatic Portosystemic Venous Shunt: To Treat or Not To Treat?

    Palvanov, Arkadiy; Marder, Ruth Leah; Siegel, David


    Intrahepatic portosystemic venous shunts (IPSVSs) are rare vascular malformations. They can be asymptomatic or present with various symptoms including encephalopathy. We present two cases of IPSVS, one involving a patient presenting with altered mental status and the other discovered incidentally. While there is no question that patients presenting with symptomatic IPSVS should undergo definitive treatment, there is no consensus regarding elective therapy for asymptomatic lesions.

  3. 脑室腹腔分流术疗效观察及堵管原因探讨%Cause of shunt system obstruction and therapeutic effect of ventriculo-peritoneal shunt

    郭伟旭; 徐丹; 张智峰; 宗盛华; 黄华; 杨波


    Objective To observe the therapeutic effect of 65 cases of ventriculo-peritoneal shunt,and analyse the cause of shunt system obstruction to reduce the complications and improve efficacy.Methods To retrospectively analyze the 65 cases of ventriculo-peritoneal shunt of the first affiliated hospital of Zhengzhou university from August 2010 to March 2012.Results Sixty-five cases had clinical symptoms improved in varying degrees.Five cases had a shunt system obstruction,including 2 cases of ventricular end of the shunt tube blockage,2 cases of shunt valve blockage,1 case of peritoneal shunt tube blockage.After replacing clogged shunt device,5 patients feel relief of preoperative symptom and went home from hospital.Conclusions The ventriculo-peritoneal shunt has exact effect to various types of hydrocephalus,actively prevention and cure for shunt system obstruction,and an accurate understanding and timely treatment of the complication is the important factor to determine prognosis of patients.%目的 观察临床65例脑室腹腔分流术的疗效,分析分流系统堵塞的原因,以减少堵塞的发生,提高疗效.方法 对2010年8月至2012年3月郑州大学第一附属医院神经外科65例行脑室腹腔分流术的病例行回顾性分析.结果 65例行脑室腹腔分流术的病例术后临床症状均有不同程度改善,5例出现分流系统堵塞,其中分流管脑室端堵塞2例,分流管阀门堵塞2例,分流管腹腔端堵塞1例,更换堵塞的分流装置后,患者待术前症状缓解后出院.结论 脑室腹腔分流术对各类脑积水疗效确切,对分流系统堵塞积极防治、准确认识、及时处理并发症能有效降低分流系统的堵塞.

  4. Active inductor shunt peaking in high-speed VCSEL driver design

    Liang, Futian; Hou, Suen; Liu, Chonghan; Liu, Tiankuan; Su, Da-Shung; Teng, Ping-Kun; Xiang, Annie; Ye, Jingbo; Jin, Ge


    An all transistor active inductor shunt peaking structure has been used in a prototype of 8-Gbps high-speed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25-um Silicon-on-Sapphire (SoS) CMOS process for radiation tolerant purpose. The all transistor active inductor shunt peaking is used to overcome the bandwidth limitation from the CMOS process. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been tapped out, and the prototype has been proofed by the preliminary electrical test results and bit error ratio test results. The driver achieves 8-Gbps data rate as simulated with the peaking. We present the all transistor active inductor shunt peaking structure, simulation and test results in this paper.

  5. Measurement of left-to-right shunts by gated radionuclide angiography: concise communication

    Rigo, P.; Chevigne, M.


    Gated cardiac blood-pool scans allow comparison of left- and right-ventricular stroke volume. We have applied these measurements to the quantification of left-to-right shunts (QP/QS) in nine patients with atrial septal defects, one patients with partial anomalous pulmonary venous return, four patients with ventricular septal defects, and two patients with patent ductus arteriosus. None of these patients had combined lesions. QP/QS was measured as the right-ventricular (RV) stroke counts divided by the left-ventricular (LV) stroke counts and as the LV stroke counts divided by the RV stroke counts in patients with RV and LV diastolic volume overload respectively. All patients had also QP/QS measurements by oximetry and first-pass radionuclide angiography. The stroke-count measurements indicated the overloaded ventricle in all patients. QP/QS determined by equilibrium gated studies correlated well with those obtained by oximetry (r . 0.79). Reproducibility of the equilibrium measurements was good. We conclude that gated cardiac blood-pool scans can measure left-to-right shunts and can distinguish between shunts with RV and LV volume overload.

  6. [Portal hypertension in children. Follow-up after portal systemic shunts (author's transl)].

    Bernard, O; Alvarez, F; Alagille, D


    The retrospective study of 115 children in whom a successful portosystemic shunt was carried out for portal hypertension, provides the following conclusions: 1) Patency of the shunt must be checked by esophageal endoscopy, six months postoperatively. A patent shunt can be expected when the size of the spleen and/or thrombocytopenia improve in the early post-operative period. Early ultrasound examination is also very useful in that respect. 2) None of the children with extrahepatic portal vein obstruction or congenital hepatic fibrosis presented with clinical signs of portal systemic encephalopathy (PSE). 3) Eight of 30 children with cirrhosis presented with one or more clinical episodes of PSE. Some were transient allowing for a normal diet to be resumed later on. 4) It is thus advisable to give children with cirrhosis a low protein diet in the months after surgery. Protein content of the diet can usually be increased progressively over a period of one to two years. 5) Whenever splenectomy is necessary, it is mandatory to prevent pneumococcal infections with the pneumococcal vaccine and daily treatment with oral penicillin.

  7. From shunting inhibition to dynamic normalization: Attentional selection and decision-making in brief visual displays.

    Smith, Philip L; Sewell, David K; Lilburn, Simon D


    Normalization models of visual sensitivity assume that the response of a visual mechanism is scaled divisively by the sum of the activity in the excitatory and inhibitory mechanisms in its neighborhood. Normalization models of attention assume that the weighting of excitatory and inhibitory mechanisms is modulated by attention. Such models have provided explanations of the effects of attention in both behavioral and single-cell recording studies. We show how normalization models can be obtained as the asymptotic solutions of shunting differential equations, in which stimulus inputs and the activity in the mechanism control growth rates multiplicatively rather than additively. The value of the shunting equation approach is that it characterizes the entire time course of the response, not just its asymptotic strength. We describe two models of attention based on shunting dynamics, the integrated system model of Smith and Ratcliff (2009) and the competitive interaction theory of Smith and Sewell (2013). These models assume that attention, stimulus salience, and the observer's strategy for the task jointly determine the selection of stimuli into visual short-term memory (VSTM) and the way in which stimulus representations are weighted. The quality of the VSTM representation determines the speed and accuracy of the decision. The models provide a unified account of a variety of attentional phenomena found in psychophysical tasks using single-element and multi-element displays. Our results show the generality and utility of the normalization approach to modeling attention.

  8. [Syringosubarachnoid shunt for noncommunicating syringomyelia associated with spinal lipoma: a case report].

    Yamamuro, Shun; Morishita, Takashi; Watanabe, Takao; Maejima, Sadahiro; Katayama, Yoichi


    Noncommunicating syringomyelia may complicate repeated untethering procedures in patients with spinal lipomas. Surgical intervention is indicated when syringomyelia is symptomatic. However, the preferred surgical procedure for noncommunicating syringomyelia associated with spinal lipomas has not been established. The authors report a case of noncommunicating syringomyelia associated with a spinal lipoma which was successfully treated with a syringosubarachnoid (S-S) shunt. The patient was a 9-year-old girl with a past history of an excision of a dermal sinus at the age of three months and an untethering of the spinal cord at the age of five. She developed a gait disturbance in the year prior to surgery, and a magnetic resonance imaging (MRI) study demonstrated syringomyelia from the second thoracic vertebra to the fourth lumbar vertebra. S-S shunt surgery successfully addressed the syringomyelia without adverse events, and a follow-up MRI study showed reduction of the size of the lesion. S-S shunt placement was therefore considered to be an effective treatment option for noncommunicating syringomyelia associated with a spinal lipoma.

  9. Modeling & Analysis of Shunt Active Power Filter Using IRP Theory Fed to Induction Drive



    Full Text Available Utility distribution networks have sensitive industrial loads and critical commercial operations suffer from various types of outages and service interruptions which can cost significant financial losses. Because of sensitivity of consumers on power quality and advancement in power electronics. Active power filter technology is the most efficient way to compensate reactive power and cancel out low order harmonics generated by nonlinear loads. The shunt active power filter was considered to be the most basic configuration for the APF. This paper reviews the basic principle of shunt active power filter, along with the current tracking circuit based on the instantaneous reactive power theory and the main circuit performing as an inverter with PWM hysteresis control. The instantaneous active and reactive current component (id-iq method and instantaneous active and reactive power (p-q method are two control strategies which are extensively used in active filters. A shunt active filter based on the instantaneous active and reactive current component (id-iq method is proposed. This method aims to compensate harmonic and first harmonic unbalance. A Comprehensive control method is analyzed and a harmonic Compensation simulation is conducted, the result of which verifies The harmonic detection algorithm is well-proposed and the power Quality of the grid is overall-enhanced. The results are obtained using MATLAB/SIMULINK software.

  10. Diffusive shunting of gases and other molecules in the renal vasculature: physiological and evolutionary significance.

    Ngo, Jennifer P; Ow, Connie P C; Gardiner, Bruce S; Kar, Saptarshi; Pearson, James T; Smith, David W; Evans, Roger G


    Countercurrent systems have evolved in a variety of biological systems that allow transfer of heat, gases, and solutes. For example, in the renal medulla, the countercurrent arrangement of vascular and tubular elements facilitates the trapping of urea and other solutes in the inner medulla, which in turn enables the formation of concentrated urine. Arteries and veins in the cortex are also arranged in a countercurrent fashion, as are descending and ascending vasa recta in the medulla. For countercurrent diffusion to occur, barriers to diffusion must be small. This appears to be characteristic of larger vessels in the renal cortex. There must also be gradients in the concentration of molecules between afferent and efferent vessels, with the transport of molecules possible in either direction. Such gradients exist for oxygen in both the cortex and medulla, but there is little evidence that large gradients exist for other molecules such as carbon dioxide, nitric oxide, superoxide, hydrogen sulfide, and ammonia. There is some experimental evidence for arterial-to-venous (AV) oxygen shunting. Mathematical models also provide evidence for oxygen shunting in both the cortex and medulla. However, the quantitative significance of AV oxygen shunting remains a matter of controversy. Thus, whereas the countercurrent arrangement of vasa recta in the medulla appears to have evolved as a consequence of the evolution of Henle's loop, the evolutionary significance of the intimate countercurrent arrangement of blood vessels in the renal cortex remains an enigma.

  11. Dual-Functional Energy-Harvesting and Vibration Control: Electromagnetic Resonant Shunt Series Tuned Mass Dampers.

    Zuo, Lei; Cui, Wen


    This paper proposes a novel retrofittable approach for dual-functional energy-harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. The viscous dissipative element between the TMD and primary system is replaced by an electromagnetic transducer shunted with a resonant RLC circuit. An efficient gradient based numeric method is presented for the parameter optimization in the control framework for vibration suppression and energy harvesting. A case study is performed based on the Taipei 101 TMD. It is found that by tuning the TMD resonance and circuit resonance close to that of the primary structure, the electromagnetic resonant-shunt TMD achieves the enhanced effectiveness and robustness of double-mass series TMDs, without suffering from the significantly amplified motion stroke. It is also observed that the parameters and performances optimized for vibration suppression are close to those optimized for energy harvesting, and the performance is not sensitive to the resistance of the charging circuit or electrical load.

  12. Sildenafil for pulmonary hypertension due to left-to-right shunt after corrective procedure

    Dyahris Kuntartiwi


    Full Text Available Background Pulmonary arterial hypertension (PAH is a common complication seen in those with a left-to-right shunt congenital heart defect (CHD. Corrective procedures by surgery or catheterization are the therapies of choice for reversible PAH. Since morbidity and mortality due to PAH after correction is high, sildenafil has been used as a selective vasodilator of the pulmonary artery, in order to decrease pulmonary arterial pressure. Objectives To evaluate the effect of sildenafil on pulmonary arterial pressure and clinical outcomes after left-to-right shunt CHD corrective procedures. Methods Left-to-right shunt patients aged < 18 years scheduled for corrective treatment were randomized in a double-blind fashion, to receive either oral sildenafil or placebo, given on days 3 to 30 after the corrective procedure. Clinical and pulmonary arterial pressures were evaluated by echocardiography before, 3 days after, and 30 days after the corrective procedure. Results From July 2013 to June 2014, 36 patients were included in the study: 17 in the placebo and 19 in the sildenafil groups. There were no differences in pulmonary arterial pressure or in clinical outcomes after corrective procedure between the two groups. There were no adverse events during the treatment. Conclusion Sildenafil has little effect on decreasing pulmonary arterial pressure, as most of our subjects seem to have hyperkinetic PAH. As such, pulmonary arterial pressure returns to normal soon after corrective procedures.

  13. Sildenafil for pulmonary hypertension due to left-toright shunt after corrective procedure

    Dyahris Kuntartiwi


    Full Text Available Background Pulmonary arterial hypertension (PAH is a common complication seen in those with a left-to-right shunt congenital heart defect (CHD. Corrective procedures by surgery or catheterization are the therapies of choice for reversible PAH. Since morbidity and mortality due to PAH after correction is high, sildenafil has been used as a selective vasodilator of the pulmonary artery, in order to decrease pulmonary arterial pressure. Objectives To evaluate the effect of sildenafil on pulmonary arterial pressure and clinical outcomes after left-to-right shunt CHD corrective procedures. Methods Left-to-right shunt patients aged < 18 years scheduled for corrective treatment were randomized in a double-blind fashion, to receive either oral sildenafil or placebo, given on days 3 to 30 after the corrective procedure. Clinical and pulmonary arterial pressures were evaluated by echocardiography before, 3 days after, and 30 days after the corrective procedure. Results From July 2013 to June 2014, 36 patients were included in the study: 17 in the placebo and 19 in the sildenafil groups. There were no differences in pulmonary arterial pressure or in clinical outcomes after corrective procedure between the two groups. There were no adverse events during the treatment. Conclusion Sildenafil has little effect on decreasing pulmonary arterial pressure, as most of our subjects seem to have hyperkinetic PAH. As such, pulmonary arterial pressure returns to normal soon after corrective procedures.

  14. Three-dimensional minority-carrier collection channels at shunt locations in silicon solar cells

    Guthrey, Harvey; Johnston, Steve; Weiss, Dirk N.; Grover, Sachit; Jones, Kim; Blosse, Alain; Al-Jassim, Mowafak


    In this contribution, we demonstrate the value of using a multiscale multi-technique characterization approach to study the performance-limiting defects in multi-crystalline silicon (mc-Si) photovoltaic devices. The combination of dark lock-in thermography (DLIT) imaging, electron beam induced current imaging, and both transmission and scanning transmission electron microscopy (TEM/STEM) on the same location revealed the nanoscale origin of the optoelectronic properties of shunts visible at the device scale. Our site-specific correlative approach identified the shunt behavior to be a result of three-dimensional inversion channels around structural defects decorated with oxide precipitates. These inversion channels facilitate enhanced minority-carrier transport that results in the increased heating observed through DLIT imaging. The definitive connection between the nanoscale structure and chemistry of the type of shunt investigated here allows photovoltaic device manufacturers to immediately address the oxygen content of their mc-Si absorber material when such features are present, instead of engaging in costly characterization.

  15. Homeostasis and the glycogen shunt explains aerobic ethanol production in yeast

    Shulman, Robert G.; Rothman, Douglas L.


    Aerobic glycolysis in yeast and cancer cells produces pyruvate beyond oxidative needs, a paradox noted by Warburg almost a century ago. To address this question, we reanalyzed extensive measurements from 13C magnetic resonance spectroscopy of yeast glycolysis and the coupled pathways of futile cycling and glycogen and trehalose synthesis (which we refer to as the glycogen shunt). When yeast are given a large glucose load under aerobic conditions, the fluxes of these pathways adapt to maintain homeostasis of glycolytic intermediates and ATP. The glycogen shunt uses glycolytic ATP to store glycolytic intermediates as glycogen and trehalose, generating pyruvate and ethanol as byproducts. This conclusion is supported by studies of yeast with a partial block in the glycogen shunt due to the cif mutation, which found that when challenged with glucose, the yeast cells accumulate glycolytic intermediates and ATP, which ultimately leads to cell death. The control of the relative fluxes, which is critical to maintain homeostasis, is most likely exerted by the enzymes pyruvate kinase and fructose bisphosphatase. The kinetic properties of yeast PK and mammalian PKM2, the isoform found in cancer, are similar, suggesting that the same mechanism may exist in cancer cells, which, under these conditions, could explain their excess lactate generation. The general principle that homeostasis of metabolite and ATP concentrations is a critical requirement for metabolic function suggests that enzymes and pathways that perform this critical role could be effective drug targets in cancer and other diseases. PMID:26283370

  16. Accommodation: The role of the external muscles of the eye: A consideration of refractive errors in relation to extraocular malfunction.

    Hargrave, B K


    Speculation as to optical malfunction has led to dissatisfaction with the theory that the lens is the sole agent in accommodation and to the suggestion that other parts of the eye are also conjointly involved. Around half-a-century ago, Robert Brooks Simpkins suggested that the mechanical features of the human eye were precisely such as to allow for a lengthening of the globe when the eye accommodated. Simpkins was not an optical man but his theory is both imaginative and comprehensive and deserves consideration. It is submitted here that accommodation is in fact a twofold process, and that although involving the lens, is achieved primarily by means of a give - and - take interplay between adducting and abducting external muscles, whereby an elongation of the eyeball is brought about by a stretching of the delicate elastic fibres immediately behind the cornea. The three muscles responsible for convergence (superior, internal and inferior recti) all pull from in front backwards, while of the three abductors (external rectus and the two obliques) the obliques pull from behind forwards, allowing for an easy elongation as the eye turns inwards and a return to its original length as the abducting muscles regain their former tension, returning the eye to distance vision. In refractive errors, the altered length of the eyeball disturbs the harmonious give - and - take relationship between adductors and abductors. Such stresses are likely to be perpetuated and the error exacerbated. Speculation is not directed towards a search for a possible cause of the muscular imbalance, since none is suspected. Muscles not used rapidly lose tone, as evidenced after removal of a limb from plaster. Early attention to the need for restorative exercise is essential and results usually impressive. If flexibility of the external muscles of the eyes is essential for continuing good sight, presbyopia can be avoided and with it the supposed necessity of glasses in middle life. Early attention

  17. Microbubbles shunting via a patent foramen ovale impair endothelial function

    Henry Fok


    Full Text Available Objectives Exposure to intravascular microbubbles after diving and during medical procedures alters endothelial function. The aim of this study was to investigate whether a patent foramen ovale altered forearm endothelial function by facilitating microbubbles transfer. Design Patients attended on two separate visits, at least seven days apart receiving agitated saline or no active intervention in random order. On both days, flow-mediated dilatation of the brachial artery was measured using vascular ultrasound. On the intervention visit, agitated saline was injected and the passage of microbubbles into the arterial circulation was confirmed by echocardiography. Serial flow-mediated dilatation measurements were made after agitated saline and at the same time points after no intervention. Setting St Thomas’ Hospital in London. Participants Patients with a patent foramen ovale (PFO+n = 14, 9 male, mean ± SD age 42.2 ± 10.5 years and patients without a patent foramen ovale (PFO− n = 10, 7 male, mean ± SD age 49.4 ± 18.4 years were recruited. Main outcome measures Change in brachial artery flow-mediated dilatation. Results In patent foramen ovale + patients, flow-mediated dilatation did not change significantly on the control day but after agitated saline reduced by 2.3 ± 0.3%, 20 minutes after bubble injection (P < 0.005 vs. corresponding change in flow-mediated dilatation during control study. There was no significant change in flow-mediated dilatation for patent foramen ovale− patients at either visit. Conclusion These results suggest that the presence of a patent foramen ovale facilitated impairment of endothelial function acutely by the transfer of microbubbles into the arterial circulation. As a patent foramen ovale is a common condition, this may be relevant to microbubbles exposure in medical procedures and in decompression illness.

  18. Development of a nonintermediate-incision ventriculoperitoneal shunt procedure using a nasogastric feeding tube for infant patients with hydrocephalus: technical note.

    Hamauchi, Shuji; Seki, Toshitaka; Sasamori, Toru; Houkin, Kiyohiro


    Intermediate incisions are considered necessary to pass a catheter tube from the head to the abdomen in ventriculo-peritoneal (VP) shunting via a frontal bur hole. However, an intermediate incision can sometimes become dehiscent, resulting in CSF leakage or infection of the shunt system in the early period after shunt implantation, particularly in infant patients. In this article, the authors describe a novel method of VP shunt insertion that does not require an intermediate incision. This nonintermediate-incision VP shunt procedure was performed in 3 infant patients with hydrocephalus and was not associated with any complications. This method can eliminate the intermediate incision, which is a disadvantage of VP shunt insertion via a frontal bur hole.

  19. Ruptured high flow gastric varices with an intratumoral arterioportal shunt treated with balloon-occluded retrograde transvenous obliteration during temporary balloon occlusion of a hepatic artery

    Motoki Nakai; Morio Sato; Hirohiko Tanihata; Tetsuo Sonomura; Shinya Sahara; Nobuyuki Kawai; Masashi Kimura; Masaki Terada


    A patient presented with hematemesis due to gastric variceal bleeding with an intratumoral arterioportal shunt. Contrast-enhanced CT revealed gastric varices and hepatocellular carcinoma with tumor thrombi in the right portal vein. Angiography and angio-CT revealed a marked intratumoral arterioportal shunt accompanied with reflux into the main portal vein and gastric varices. Balloon-occluded retrograde venography from the gastro-renal shunt showed no visualization of gastric varices due to rapid blood flow through the intratumoral arterioportal shunt. The hepatic artery was temporarily occluded with a balloon catheter to reduce the blood flow through the arterioportal shunt, and then concurrent balloon-occluded retrograde transvenous obliteration (BRTO) was achieved. Vital signs stabilized immediately thereafter, and contrast-enhanced CT revealed thrombosed gastric varices. Worsening of hepatic function was not recognized. BRTO combined with temporary occlusion of the hepatic artery is a feasible interventional procedure for ruptured high flow gastric varices with an intratumoral arterioportal shunt.

  20. Oxidative Stress and Total Antioxidant Status During Internal Carotid Artery Clamping with or without Shunting: An Experimental Pilot Study.

    Papapetrou, Anastasios; Moris, Demetrios; Patelis, Nikolaos; Kouvelos, George N; Bakogiannis, Chris; Klonaris, Chris; Georgopoulos, Sotiris


    BACKGROUND The exact role of shunting during carotid endarterectomy remains controversial and unclear. The aim of this experimental study was to investigate to what degree carotid clamping may induce changes in the cerebral oxidative status and to focus on the relation of these changes with shunt insertion. MATERIAL AND METHODS Forty New-Zealand rabbits were randomized into 4 groups: group 1 classifying animals with carotid shunt and patent contralateral carotid artery; group 2 shunt and occlusion of the contralateral carotid artery; group 3 no-shunt and patent contralateral carotid artery; and group 4 no-shunt and occlusion of the contralateral carotid artery. Blood samples were collected from the ipsilateral internal jugular vein, immediately after carotid clamping (time 0), and then at 5, 10, 15, 30, and 60 minutes afterwards. Evaluation of oxidative stress was accomplished by measuring the lag-time, representing the initial phase of oxidation, rate of accumulation (RA), showing concentration of free oxygen radical and total antioxidant status (TAS) representing antioxidant composition of serum. RESULTS Lag-time was significantly different in time points 0, 30 and 60 minutes within each different group. TAS was significantly different in time points 0, 15 and 60 min and RA in time points 0, 5, 10 and 60 min within each different group. 60 minutes after carotid clamping, the rate of accumulation as well as lag-time and TAS were increased in all groups, independently of using or not shunting or the presence of contralateral occlusion. After comparing groups 1, 2 and 3 regarding lag-time, TAS and RA, we did not find statistical difference among the groups at any time point. On the contrary, groups 1, 2 and 3 did show significantly different values comparing to group 4 after 60 min of occlusion. CONCLUSIONS Our experimental work based on cerebral metabolism found a significantly higher oxidative stress in models with contralateral carotid occlusion. The use of shunt