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Sample records for acute shunt malfunction

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

    Science.gov (United States)

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

    2015-10-01

    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.

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

    Science.gov (United States)

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

    2015-10-01

    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. PMID:26186358

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

    Science.gov (United States)

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

    2016-08-01

    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].

    Science.gov (United States)

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

    2014-12-01

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

    Science.gov (United States)

    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

    2016-04-01

    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. PMID:26636251

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

    Science.gov (United States)

    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

    2016-04-01

    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. Ventricular enlargement due to acute hypernatremia in a patient with a ventriculoperitoneal shunt.

    Science.gov (United States)

    Andres, Robert H; Pendharkar, Arjun V; Kuhlen, Dominique; Mariani, Luigi

    2010-07-01

    Patients requiring CSF shunts frequently have comorbidities that can influence water and electrolyte balances. The authors report on a case involving a ventriculoperitoneal shunt in a patient who underwent intravenous hyperhydration and withdrawal of vasopressin substitution prior to scheduled high-dose chemotherapy regimen for a metastatic suprasellar germinoma. After acute neurological deterioration, the patient underwent CT scanning that demonstrated ventriculomegaly. A shunt tap revealed no flow and negative opening pressure. Due to suspicion of proximal shunt malfunction, the comatose patient underwent immediate surgical exploration of the ventricle catheter, which was found to be patent. However, acute severe hypernatremia was diagnosed during the procedure. After correction of the electrolyte disturbances, the patient regained consciousness and made a good recovery. Although rare, the effects of acute severe hypernatremia on brain volume and ventricular size should be considered in the differential diagnosis of ventriculoperitoneal shunt failure. PMID:19911884

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

    Science.gov (United States)

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

    2012-01-01

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

    Science.gov (United States)

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

    2010-01-01

    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

  10. Effect of Prone Position on Regional Shunt, Aeration, and Perfusion in Experimental Acute Lung Injury

    OpenAIRE

    Richter, Torsten; Bellani, Giacomo; Harris, R. Scott; Melo, Marcos F. Vidal; Winkler, Tilo; Venegas, Jose G.; Musch, Guido

    2005-01-01

    Rationale: The prone position is used to improve gas exchange in patients with acute respiratory distress syndrome. However, the regional mechanism by which the prone position improves gas exchange in acutely injured lungs is still incompletely defined. Methods: We used positron emission tomography imaging of [13N]nitrogen to assess the regional distribution of pulmonary shunt, aeration, perfusion, and ventilation in seven surfactant-depleted sheep in supine and prone positions. Results: In t...

  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

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    Hayes Jackson

    2012-11-01

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

    Directory of Open Access Journals (Sweden)

    Sheri K Palejwala

    2014-01-01

    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.

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

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    Rajendra K Ghritlaharey

    2012-01-01

    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.

  14. Transjugular Intrahepatic Portosystemic Shunt, Mechanical Aspiration Thrombectomy, and Direct Thrombolysis in the Treatment of Acute Portal and Superior Mesenteric Vein Thrombosis

    International Nuclear Information System (INIS)

    A patient was admitted because of severe abdominal pain, anorexia, and intestinal bleeding. Contrast-enhanced multidetector computed tomography demonstrated acute portal and superior mesenteric vein thrombosis (PSMVT). The patient was treated percutaneously with transjugular intrahepatic portosystemic shunt (TIPS), mechanical aspiration thrombectomy, and direct thrombolysis, and 1 week after the procedure, complete patency of the portal and superior mesenteric veins was demonstrated. TIPS, mechanical aspiration thrombectomy, and direct thrombolysis together are promising endovascular techniques for the treatment of symptomatic acute PSMVT

  15. Factors affecting ventriculoperitoneal shunt survival in adult patients

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    Farid Khan

    2015-01-01

    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.

  16. Ventriculoperitoneal shunt infections

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    Sarguna P

    2006-01-01

    Full Text Available Central nervous system (CNS shunt infection is a cause of significant morbidity, causing shunt malfunction and chronic ill health. This study was carried out to evaluate the infection rate associated with CNS shunts, assess the frequency of the pathogens as well as their antibiotic sensitivity pattern aiming at suitable prophylaxis. A retrospective analysis of 226 CSF cerebrospinal fluid (CSF shunt procedures sent for bacteriological work up over a period of one year and six months was undertaken. Laboratory diagnosis was established by subjecting the CSF to cell count, biochemical tests, bacteriological culture and antibiotic susceptibility test. Nine out of 226(3.98% of the CSF samples were culture positive. Coagulase negative Staphylococcus was the most common isolate accounting for 36.36%. Majority of the isolates were sensitive to the thirdgeneration cephalosporins and quinolones. The antibiotic sensitivity pattern suggests cephalosporins and quinolones to be a better choice of antibiotics either prophylactically or therapeutically, which may result in effective and rapid sterilisation of the CSF.

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

    LENUS (Irish Health Repository)

    Mohammed, Wail

    2011-02-01

    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.

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

    LENUS (Irish Health Repository)

    Mohammed, Wail

    2012-02-01

    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. Rescue endoscopic third ventriculostomy for repeated shunt blockage

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    Puneet K Goyal

    2011-01-01

    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.

  20. Lumboperitoneal shunts: Review of 409 cases

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    Yadav Y

    2004-04-01

    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.

  1. Ventriculoperitoneal shunt

    Science.gov (United States)

    ... belly. A small hole is drilled in the skull. A thin tube called a catheter is passed ... of ventriculoperitoneal shunt. In: Jandial R, McCormick PC, Black PM, eds. Core Techniques in Operative Neurosurgery . Philadelphia, ...

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

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    Hajime Takase

    2014-01-01

    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.

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    International Nuclear Information System (INIS)

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future

  4. Transjugular intrahepatic portosystemic shunt.

    Science.gov (United States)

    Ochs, Andreas

    2005-01-01

    The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment resulting in decompression of the portal system by creation of a side-to-side portosystemic anastomosis. Since its introduction 16 years ago, more than 1,000 publications have appeared demonstrating broad acceptance and increasing clinical use. This review summarizes our present knowledge about technical aspects and complications, follow-up of patients and indications. A technical success rate near 100% and a low occurrence of complications clearly depend on the skills of the operator. The follow-up of the TIPS patient has to assess shunt patency, liver function, hepatic encephalopathy and the possible development of hepatocellular carcinoma. Shunt patency can best be monitored by duplex sonography and can avoid routine radiological revision. Short-term patency may be improved by anticoagulation, while such a treatment does not influence long-term patency. Stent grafts covered with expanded polytetrafluoroethylene show promising long-term patency comparable with that of surgical shunts. With respect to the indications of TIPS, much is known about treatment of variceal bleeding and refractory ascites. The thirteen randomized studies that are available to date show that survival is comparable in patients receiving TIPS or endoscopic treatment for acute or recurrent variceal bleeding. Another group comprises patients with refractory ascites and related complications, such as hepatorenal syndrome and hepatic hydrothorax. It has been demonstrated that TIPS improves these complications. Five randomized studies comparing TIPS with paracentesis and one study comparing TIPS with the peritoneo-venous shunt showed good response of ascites but controversial results on survival. In addition, TIPS has been successfully applied to patients with Budd-Chiari syndrome, portal vein thrombosis, before liver transplantation, and for the treatment of ectopic variceal bleeding. PMID:15920326

  5. A new logic of technical malfunction

    OpenAIRE

    Jespersen, Bjørn; Carrara, Massimiliano

    2013-01-01

    Aim of the paper is to present a new logic of technical malfunction. The need for this logic is motivated by a simple-sounding philosophical question: Is a malfunctioning corkscrew, which fails to uncork bottles, nonetheless a corkscrew? Or in general terms, is a malfunctioning F, which fails to do what Fs do, nonetheless an F? We argue that ‘malfunctioning’ denotes the modifier Malfunctioning rather than a property, and that the answer depends on whether Malfunctioning is subsective or priva...

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

    Energy Technology Data Exchange (ETDEWEB)

    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))

    1993-10-01

    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. Complications of Denver Shunt

    OpenAIRE

    Eranga Perera; Shweta Bhatt; Vikram S Dogra

    2011-01-01

    Hepatic hydrothorax secondary to transdiaphragmatic spread of peritoneal fluid can cause respiratory discomfort to the patient. Draining of hydrothorax helps relieve these symptoms. Pleurovenous shunt (Denver shunt) is a relatively non-invasive method of shunting the pleural fluid to the central venous system. Reported complications of pleurovenous shunts are shunt failure, pulmonary edema, post shunt coagulopathy, deep vein thrombosis, and infection. We report a rare case of a leak at the ve...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-04-01

    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.

  9. Complications of Denver Shunt

    Directory of Open Access Journals (Sweden)

    Eranga Perera

    2011-01-01

    Full Text Available Hepatic hydrothorax secondary to transdiaphragmatic spread of peritoneal fluid can cause respiratory discomfort to the patient. Draining of hydrothorax helps relieve these symptoms. Pleurovenous shunt (Denver shunt is a relatively non-invasive method of shunting the pleural fluid to the central venous system. Reported complications of pleurovenous shunts are shunt failure, pulmonary edema, post shunt coagulopathy, deep vein thrombosis, and infection. We report a rare case of a leak at the venous end of the catheter that was placed within the right internal jugular vein, resulting in a large collection in the neck.

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

    Directory of Open Access Journals (Sweden)

    Ugur Yazar

    2012-01-01

    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.

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

    Science.gov (United States)

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

    2016-10-01

    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.

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

    Science.gov (United States)

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

    2016-10-01

    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. PMID:27589973

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

    Science.gov (United States)

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

    2013-06-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Sandesh V Parelkar

    2014-01-01

    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.

  15. The peritoneo-venous shunts of Le Veen and the testing of its function

    International Nuclear Information System (INIS)

    A radio technique for testing the patency of, peritoneo-venous shunts of Le Veen, is reported and is demonstrated by discussing a case history. By now a total number of 16 patients have been tested, after implantation of such a shunt. The demonstrated radioisotope technique, which causes no complaints from the patient, is not only able to inform concerning the functional state of the Le Veen shunts, but also, in case of disturbances, is able to reveal the cause of the underlying malfunctions. (author)

  16. Endoscopic Third Ventriculostomy in Previously Shunted Children

    Directory of Open Access Journals (Sweden)

    Eva Brichtova

    2013-01-01

    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.

  17. Lumbar peritoneal shunt

    Directory of Open Access Journals (Sweden)

    Yadav Yad

    2010-01-01

    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.

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

    Science.gov (United States)

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

    2016-04-01

    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

  19. Neurocomputational Nosology: Malfunctions of Models and Mechanisms

    Directory of Open Access Journals (Sweden)

    David L Barack

    2016-05-01

    Full Text Available Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those cognitive functions. Mechanisms in the form of repeated patterns of neural dynamics execute information processing models. Two distinct modes of malfunction can occur when neural dynamics execute models of information processing. The processing models describing behavior may fail to be executed correctly by neural mechanisms. Or, the neural mechanisms may malfunction, failing to implement the right computation. As an example of malfunctioning models in executive cognition, purported failures of rule following can be understood as failures to appropriately execute a suite of processing models. As an example of malfunctioning mechanisms of executive cognition, maladaptive behavior resulting from dysfunction in the medial prefrontal cortex can be understood as failures in the signal transformations carried out therein. The purpose of these examples is to illustrate the potential benefits of considering models and mechanisms in the diagnosis and etiology of neuropsychological illness and dysfunction, especially disorders of executive cognition.

  20. Neurocomputational Nosology: Malfunctions of Models and Mechanisms.

    Science.gov (United States)

    Barack, David L; Platt, Michael L

    2016-01-01

    Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those cognitive functions. Mechanisms in the form of repeated patterns of neural dynamics execute information processing models. Two distinct modes of malfunction can occur when neural dynamics execute models of information processing. The processing models describing behavior may fail to be executed correctly by neural mechanisms. Or, the neural mechanisms may malfunction, failing to implement the right computation. As an example of malfunctioning models in executive cognition, purported failures of rule following can be understood as failures to appropriately execute a suite of processing models. As an example of malfunctioning mechanisms of executive cognition, maladaptive behavior resulting from dysfunction in the medial prefrontal cortex (mPFC) can be understood as failures in the signal transformations carried out therein. The purpose of these examples is to illustrate the potential benefits of considering models and mechanisms in the diagnosis and etiology of neuropsychological illness and dysfunction, especially disorders of executive cognition. PMID:27199835

  1. Exit ventriculoperitoneal shunt; enter endoscopic third ventriculostomy (ETV): contemporary views on hydrocephalus and their implications on management

    OpenAIRE

    Kamalo, P

    2013-01-01

    Hydrocephalus has been known to affect humans since the birth of human medicine as it is described by Hippocrates. The management of this condition is however still dodged by challenges due to a poor understanding of its pathophysiology. The ventriculoperitoneal shunt presents considerable problems especially with respect to infection and shunt malfunction. Low income countries, that currently face the greater burden of paediatric hydrocephalus. experience an increased challenge with ventricu...

  2. Distal splenorenal shunt

    Science.gov (United States)

    ... 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 ...

  3. Pathophysiology of shunt dysfunction in shunt treated hydrocephalus

    DEFF Research Database (Denmark)

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

    2013-01-01

    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....

  4. 76 FR 12743 - Medical Device Reporting; Malfunction Reporting Frequency

    Science.gov (United States)

    2011-03-08

    ... HUMAN SERVICES Food and Drug Administration Medical Device Reporting; Malfunction Reporting Frequency... continue to submit malfunction reports in full compliance with FDA's Medical Device Reporting regulation...) is clarifying that device manufacturers and importers of all devices, including class I and...

  5. Neurocomputational Nosology: Malfunctions of Models and Mechanisms

    OpenAIRE

    Barack, David L.; Platt, Michael L.

    2016-01-01

    Executive dysfunctions, psychopathologies arising from problems in the control and regulation of behavior, can occur as a result of the faulty execution of formal information processing models or as a result of malfunctioning neural mechanisms. The models correspond to the formal descriptions of how signals in the environment must be transformed in order to behave adaptively, and the mechanisms correspond to the signal transformations that nervous systems implement in order to execute those c...

  6. Percutaneous gastrostomy tube placement in patients with ventriculoperitoneal shunts

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1998-07-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Efstratios Athanasakis

    2011-01-01

    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.

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

    Science.gov (United States)

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

    2016-01-01

    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.

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

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27652453

  10. Magnetic fields and intrathecal pump malfunction.

    Science.gov (United States)

    Huh, Billy; Roldan, Carlos J

    2016-01-01

    Medical technology has impacted the overall life expectancy. Many conditions traditionally considered fatal are now curable. Surviving chronic diseases and aging of the population have increased the number of people with chronic pain. Many devices are also available to manage severe refractory pain. As such, implantable drug-delivery system (IDDS) is a small battery-powered, programmable pump implanted under the subcutaneous tissue of the abdomen and connected to a small catheter tunneled into the spine. Implantable drug-delivery system is used for the administration of morphine, ziconotide, baclofen, or their mixtures into the cerebrospinal fluid. Like many medical devices, IDDS has technical glitch which limits its performance under certain conditions. Implantable drug-delivery system is susceptible to magnetic field such as a magnetic resonance imaging (MRI) which can temporarily stall the rotor of the pump motor and suspend drug delivery. We encountered a patient from out of town seen at emergency department with increased pain and symptoms of opiates withdrawal after intermittent IDDS malfunction. He denied any exposure to magnetic fields or MRI. However, the pump interrogation showed multiple motor stall events in the event log. After a detailed inquiry, the most likely cause of pump malfunction appears to be frequent placement of a laptop computer on his abdomen close to the pump. The magnets in the laptop speakers may have caused the rotor of the pump motor to stall during the computer use, and frequent stall has caused symptoms of withdrawal. No other mechanical failures were found. The patient was discharged home after the symptoms resolved, and the pump was reprogrammed. PMID:26008580

  11. Congenital extrahepatic portosystemic shunts

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2003-09-01

    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.)

  12. Control Rod Malfunction at the NRAD Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L. Maddock

    2010-05-01

    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.

  13. Outcome analysis of shunt surgery in hydrocephalus

    Directory of Open Access Journals (Sweden)

    Ahmed Ashraf

    2009-01-01

    Full Text Available Aim: To study the clinical outcome of shunt surgeries in children suffering from hydrocephalus. Methods: A prospective study of 50 children with hydrocephalus who underwent a ventriculo-peritoneal shunt insertion over a period of two years. These patients were then followed up for shunt related complications, shunt revisions and outcome. Results : Twenty six of the 50 patients (52% suffered from complications. The most common complications were shunt blockage (n=7 and shunt infection (n=6. These complications necessitated repeated shunt revisions. Conclusions: Infective complications of hydrocephalus are more likely to leave behind an adverse neurological outcome in the form of delayed milestones and mental retardation.

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

    Directory of Open Access Journals (Sweden)

    Narendra R. Dereddy

    2015-10-01

    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.

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

    OpenAIRE

    Dereddy, Narendra R.; Chilakala, Sandeep R.; Divya Rana

    2015-01-01

    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.

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... anti-inflammatory drugs (NSAIDs) or blood thinners several days prior to your procedure and instructed to not ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) About ...

  18. Automatic detection and analysis of nuclear plant malfunctions

    International Nuclear Information System (INIS)

    In this paper a system is proposed, which performs dynamically the detection and analysis of malfunctions in a nuclear plant. The proposed method was developed and implemented on a Reactor Simulator, instead of on a real one, thus allowing a wide range of tests. For all variables under control, a simulation module was identified and implemented on the reactor on-line computer. In the malfunction identification phase all modules run separately, processing plant input variables and producing their output variable in Real-Time; continuous comparison of the computed variables with plant variables allows malfunction's detection. At this moment the second phase can occur: when a malfunction is detected, all modules are connected, except the module simulating the wrong variable, and a fast simulation is carried on, to analyse the consequences. (author)

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

    Directory of Open Access Journals (Sweden)

    Babak ABDINIA

    2013-01-01

    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.

  20. 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

    Institute of Scientific and Technical Information of China (English)

    李雄; 赵奇煌; 李锦平

    2014-01-01

    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

  1. Shunting ratios for MHD flows

    Energy Technology Data Exchange (ETDEWEB)

    Birzvalk, Yu.

    1978-01-01

    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.

  2. Piezoelectric RL shunt damping of flexible structures

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Krenk, Steen

    2015-01-01

    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...

  3. Percutaneous Transjugular Direct Porto-caval Shunt in Patients with Budd-Chiari Syndrome

    International Nuclear Information System (INIS)

    The purpose of the study was to evaluate the feasibility and effectiveness of direct porto-caval shunts in patients with Budd-Chiari syndrome (BCS) in whom there is no access to the hepatic veins during transjugular intrahepatic portosystemic shunt (TIPSS). We included six consecutive patients with fulminant/acute Budd-Chiari syndrome (mean age: 35 years) in whom a conventional TIPSS was not possible due to inaccessible hepatic veins. We performed a direct porto-caval shunt via a transhepatic approach. Patients were followed up by means of clinical examination, laboratory investigations, and Doppler ultrasound. TIPSS implantation from the inferior vena cava (IVC) was successful in all six patients (100%). The median transhepatic shunt length was 9 cm (8-10 cm). No procedure-related complications were observed in our patients. Early shunt occlusion occurred in three out of six patients (50%). In all three of these patients, the stent used to stabilize the shunt ended 1-2 cm before reaching the IVC. All occlusions were successfully recanalized. One of these patients developed recurrent early shunt as well as mesenteric and splenic vein occlusions. She died 7 days after TIPSS placement due to an unmanageable coagulation disorder. The remaining five patients were followed up by planned clinical examination and laboratory investigations (mean follow-up time was 15 months; patient 1 was followed up for 13 months, patient 2 for 14 months, patient 3 for 15 months, and patients 4 and 5 for 16 months) and all displayed a complete and durable resolution of liver failure and ascites without reintervention. In patients with acute liver failure originating from BCS and inaccessible hepatic veins, a direct transhepatic porto-caval shunt can be performed safely and effectively under ultrasound guidance. Future studies in larger patient groups should investigate if the patency of transcaval TIPSS with long transhepatic shunt segments is similar compared to conventional TIPSS via

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

    Energy Technology Data Exchange (ETDEWEB)

    Bruckheimer, Elchanan, E-mail: elchananb@bezeqint.net; 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)

    2013-12-15

    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.

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

    International Nuclear Information System (INIS)

    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 ∼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 μmol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia

  6. Severe respiratory failure following ventriculopleural shunt

    OpenAIRE

    Shahzad Alam; Manjunath, Nagaraju M.

    2015-01-01

    Cerebrospinal fluid (CSF) diversion procedure has been used for long to treat hydrocephalus in children. The principle of shunting is to establish a communication between the CSF and a drainage cavity (peritoneum, right atrium, and pleura). Ventriculoperitoneal shunt is used most commonly, followed secondly by ventriculopleural shunt (VPLS). Hydrothorax due to excessive CSF accumulation is a rare complication following both the type of shunts and is more frequently seen with VPLS. We report a...

  7. Scintigraphic demonstration of the permeability of peritoneo-caval shunts (Denver's shunts)

    International Nuclear Information System (INIS)

    The functional ability of a peritoneo-caval shunt ('Denver's' Shunt) can be examined in a physiological manner by means of nuclear medical procedures. For this purpose macroaggregated albumin particles used for lung scintigraphy are injected intraperitoneally. The visualization of these particles within the lung capillaries, combined with the possibility of recording a lung perfusion scintigram, gives evidence of the regular function of the shunt. In many cases, scintigraphy also reveals the course of the shunt itself. This enables the shunt to be saved because shunt puncture is not necessary. Such puncture would be required only for X-ray localisation using contrast media in cases of proven shunt occlusion. (orig.)

  8. Detection of thermocouple malfunction in the Beacon system

    International Nuclear Information System (INIS)

    The BEACON system uses Core Exit Thermocouples (T/C) extensively for continuous radial power distribution monitoring. The T/C's are used to adjust the reference power distribution generated by the BEACON system to match the current radial power distribution. T/C reliability, repeatability, and relative accuracy have been very satisfactory. However, it is very important to detect any T/C malfunctions during operation, since a T/C signal change caused by an undetected malfunction can lead to serious errors in the radial power distribution developed by BEACON. A simple procedure has been developed which is capable of discriminating between changes in T/C signals caused by actual changes in reactor conditions and signal changes caused by T/C malfunctions

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

    Directory of Open Access Journals (Sweden)

    Tomoaki Kano

    2014-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Arata Tomiyama

    2014-01-01

    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.

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... overnight at the hospital for one or more days. What is Transjugular Intrahepatic Portosystemic Shunt (TIPS)? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    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 ( ...

  13. Ectopic cystoperitoneal shunt demonstrated by valvulography. A case report

    International Nuclear Information System (INIS)

    The most important and frequent complications in the management of hydrocephalus treated with a derivation system are the infection and obstruction of the ventriculoperitoneal or ventriculoatrial shunt. However, another less frequent problem is the migration of the distal catheter. The case report presented is a 20 year-old girl who started, when she was 12, with severe headaches and epileptogenic seizures. She was diagnosed with a left parietotemporal aracnoidal cyst and a cystoperitoneal shunt was installed. However, she continued to have headaches. In September 1999, the derivation system was controlled with a radionuclide valvulography, which demonstrated shunt patency, with mild ectasis in the distal region. In July 2000, another valvulography showed a malfunction of the cystoperitoneal system. The distal catheter was surgically reviewed and repositioned. A few months of being asymptomatic, the headaches returned with a cough, which didn't respond to treatment. In February of 2002, she was referred to the Military Hospital Nuclear Medicine Department and a radionuclide valvulography was performed with 370 MBq of Tc99m-DTPA, injected in the derivative system reservoir. Images showed a slow descension of the radionuclide until the xifoides region where the distal catheter had formed a loop into the chest. Free activity was observed at the end of the catheter with another abnormal traject in the middle chest up to the top of the sternum. A pumping test was done and the patient coughed and said that she 'felt water' in her mouth. A simple abdomen X-ray was performed confirming the distal catheter in the upper side of the diaphragm. A third surgery was performed demonstrating that the catheter had an intraperitoneal loop with the distal end in the chest. They pulled the catheter and the distal end was repositioned into the peritoneal cavity, controlling its functioning. A simple abdomen X-ray verified the position. In the following days the patient had no headache

  14. Cervical puncture and perimedullary cistern shunt placement for idiopathic intracranial hypertension: An alternative to lumbar cistern or cerebral ventricular catheter placement a report of two cases

    OpenAIRE

    Johnson, Jeremiah N.; Elhammady, Mohamed Samy; Theodotou, Christian B.; Ashour, Ramsey; Aziz-Sultan, Mohammad Ali

    2014-01-01

    Objective: Idiopathic intracranial hypertension (IIH) is a syndrome characterized by increased intracranial pressure (ICP) in the absence of an identifiable cause, and if untreated, can result in permanent vision loss. In symptomatic IIH patients, cerebrospinal fluid (CSF) diversion can lower ICP and protect vision; however, currently used CSF diversion systems are prone to malfunction in this population. Materials and Methods: In two IIH patients with histories of numerous prior shunt revisi...

  15. Effect of peritoneo-venous shunt on portal pressure.

    Science.gov (United States)

    Samanta, A K; Leevy, C M

    1989-01-01

    The cause of variceal bleed after a peritoneo-venous shunt is not known. Portal haemodynamic consequences of a peritoneo-venous shunt are poorly understood. The most critical period after a peritoneo-venous shunt is the early postoperative period when rapid mobilisation of peritoneal fluid occurs. Serial changes in the portal pressure during the early postoperative period have not been recorded. In the present study preoperative wedge hepatic vein (WHV), right atrial (RA) and pulmonary capillary wedged (PCW) pressures, cardiac index (CI), and plasma volume (PV) were measured in five alcoholic cirrhotic patients with tense ascites for up to 20 hours postoperatively. The longterm effect was assessed by repeating the intrahepatic and/or wedged hepatic vein pressures in three of the surviving patients after 10 to 20 months. A significant increase in the circulatory dynamics and portal pressure was seen within two hours after shunt placement. Wedged hepatic vein pressure increased from 27.6 (8.2) mmHg to 37.2 (9.2) mmHg (p less than 0.01), RA pressure increased from 6.8 (1.5) mmHg to 14.0 (4.3) mmHg (p less than 0.05), PCW increased from 7.2 (3.5) mmHg to 19.3 (5.7) mmHg (p less than 0.01), CI increased from 3.4 (0.27) lit/m2/min to 4.3 (0.85) lit/m2/min (p less than 0.05). This was accompanied by a 34% increase in the plasma volume from 1838.5 (142.1) to 2471.4 (210) ml/m2. These derangements were maintained up to 20 hours postoperatively. After 10 to 20 months, repeat measurements revealed a return to preoperative measurements. It is concluded that there is an acute increase portal pressure after a peritoneo-venous shunt attributed to increased circulation plasma volume, resulting from rapid mobilisation of ascitic fluid after the shunt. A sudden increase in portal pressure might be an important provoking factor for variceal bleeding after peritoneo-venus shunt. PMID:2920931

  16. A wireless monitoring system for Hydrocephalus shunts.

    Science.gov (United States)

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

    2015-08-01

    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.

  17. Classification system for reporting events involving human malfunctions

    International Nuclear Information System (INIS)

    The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchial structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data processes and their typical malfunctions and of a human decision sequence are described. (author)

  18. Echocardiographic analysis of a malfunctioning Davila-Sierra mitral valve

    OpenAIRE

    Tri, Terry B.; Gregoratos, Gabriel

    1981-01-01

    Although the Davila-Sierra mitral valve prosthesis was removed from the market nearly a decade ago, a number of patients still have this valve in place. We recently studied the echocardiographic features of a malfunctioning Davila-Sierra mitral valve prosthesis. Abnormalities that suggested improper functioning of the prosthesis included a markedly delayed poppet opening and an early diastolic hump believed to represent motion of the mitral annulus. Previously described echocardiographic indi...

  19. Percutaneous Retroperitoneal Splenorenal Shunt for Symptomatic Portal Vein Thrombosis After Liver Transplantation.

    Science.gov (United States)

    Pulitano, C; Rogan, C; Sandroussi, C; Verran, D; McCaughan, G W; Waugh, R; Crawford, M

    2015-08-01

    Acute or recurrent bleeding from ectopic varices is a potentially life-threatening condition in rare patients with extrahepatic complete portal vein thrombosis (PVT) after liver transplantation (LT). In this setting, the role of interventional radiology is very limited and surgical shunts, in particular splenorenal shunts are usually used, despite the high associated mortality. We present the first reports of the clinical use of a new minimally invasive technique, percutaneous retroperitoneal splenorenal shunt (PRESS), in two LT recipients with life-threatening variceal hemorrhage secondary to PVT. Both patients had a successful PRESS using a transplenic approach with resolution of bleeding, avoiding the need for a potentially complicated laparotomy. The PRESS procedure is a useful addition to the interventional armamentarium that can be used in cases unsuitable for surgical shunt, and refractory to endoscopic management. In the future, this technique may be an alternative to surgical shunts as the standard procedure in patients with extra-hepatic PVT, just as the transjugular intrahepatic portosystemic shunt (TIPS) procedure has become for the management of portal hypertension in the absence of PVT. Longer-term follow-up will be needed to establish the long-term success of this procedure. PMID:25980940

  20. Intra-abdominal metastasis of an intracranial germinoma via ventriculo-peritoneal shunt in a 13-year-old female.

    Science.gov (United States)

    Murray, Matthew J; Metayer, Lucy E; Mallucci, Conor L; Hale, Juliet P; Nicholson, James C; Kirollos, Ramez W; Burke, G A Amos

    2011-12-01

    A 13-year-old patient presented with massive intra-abdominal metastasis and spontaneous acute tumour lysis syndrome, 17-months after VP shunt placement for metastatic pineal germinoma treated with cranio-spinal-irradiation. Hyperhydration/rasburicase improved renal function, allowing chemotherapy with subsequent surgery. The patient remains event-free 34-months later. Risk of intra-abdominal metastasis from VP shunts is discussed. PMID:21501064

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    Fourteen years after shunt implantation, a 26-year-old patient with myelomeningocele, concomitant hydrocephalus and a ventriculoatrial cerebrospinal fluid (CSF) shunt presented with brief but recurrent episodes of fever predominantly when taking showers or during physical exertion. After 4 years...

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

    Directory of Open Access Journals (Sweden)

    Petros Charalampoudis

    2012-01-01

    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.

  3. Scintigraphic demonstration of the permeability of peritoneo-caval shunts (Denver's shunts)

    Energy Technology Data Exchange (ETDEWEB)

    Grehn, S.; Pingel, B.

    1988-02-01

    The functional ability of a peritoneo-caval shunt ('Denver's' Shunt) can be examined in a physiological manner by means of nuclear medical procedures. For this purpose macroaggregated albumin particles used for lung scintigraphy are injected intraperitoneally. The visualization of these particles within the lung capillaries, combined with the possibility of recording a lung perfusion scintigram, gives evidence of the regular function of the shunt. In many cases, scintigraphy also reveals the course of the shunt itself. This enables the shunt to be saved because shunt puncture is not necessary. Such puncture would be required only for X-ray localisation using contrast media in cases of proven shunt occlusion.

  4. Method of diagnosis of functional intrapulmonary shunts

    International Nuclear Information System (INIS)

    A method of diagnosing functional intrapulmonary shunts is suggested, that permits to obtain the data on the amount, localization and sizes of shunts. This method can be used in the clinic of internal deseases to determine the state of cardiopulmonary patients

  5. Congenital Portosystemic Shunt: Our Experience

    Directory of Open Access Journals (Sweden)

    Tiziana Timpanaro

    2015-01-01

    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.

  6. Radioisotopic evaluation of peritoneo-venous shunt patency by intraperitoneal injection of 99m-Tc-human albumin microspheres

    International Nuclear Information System (INIS)

    The results demonstrate that 99m Tc-human albumin microspheres always reach the lungs when the shunt is patent. On the contrary, in presence of malfunctioning, they are either confined below the diaphragm or stopped at some point along the tube according to the site of interruption, either in the valve or in venous limb of the shunt. A second injection of the tracer directly into the subcutaneous portion of the tube, immediately above the valve, proved to be very useful to confirm the valvular site of obstruction. The early visualization of the tube seems to indicate a normal flow through the valve even when the last segment of the shunt is obstructed. A poor image of the tube and a delayed accumulation of the tracer in the lungs could indicate the presence of a nonfunctioning valve; in this case, however, an associated heart disease must be ruled out. The present radioisotopic technique prompts early surgical revision when the shunt is not patent. Although the site of interruption can not be exactly determined, the method discriminates between valve and tube shut-off, thus avoiding the replacement of the whole apparatus. This radioisotopic method should be used routinely for the control of PVS patency in cirrhotic patients. Though slightly invasive, it is simple and time-saving. Finally, 99m Tc-human albumin microspheres are useful radioactive tracers because of their easy passage into the LeVeen tube and their homogeneous diffusion in the lungs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-15

    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.)

  8. [Systemic-pulmonary artery shunt using Golaski graft: trial for measurement of the shunt flow].

    Science.gov (United States)

    Togo, T; Ito, T; Hata, M; Murata, S; Osaka, K; Komatsu, T; Tabayashi, K; Haneda, K; Mohri, T

    1995-03-01

    For the systemic-pulmonary artery shunt operation, the modified Blalock-Taussig shunt was the first choice for procedure in our institution. Since 1990, Golaski knitted Dacron graft (4 or 5 mm in diameter) was used for the prosthesis. Ex-vivo flow calibration of the electromagnetic flow meter (Nihon Koden, MFV-3100) to Golaski graft showed good correlation between the real flow and value measured by the electromagnetic flow meter. Shunt flow was measured in the consecutive clinical fifteen cases. The shunt flow per body surface area of the patient who required additional shunt operation was 721 ml/min/m2 and one patient in whom the congestive heart failure developed after the shunt operation, had the shunt flow of 3,022 ml/min/m2. The adequate shunt flow in these cases was ranged from 745 to 2,820 ml/min/m2 (mean +/- 1 SD, 1,490 +/- 587.8). Therefore we performed the systemic-pulmonary artery shunt operation using Golaski graft to get the shunt flow of 1,000 ml/min/m2 (approximately a third of cardiac index) for the guide of good results. PMID:7897896

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

    Institute of Scientific and Technical Information of China (English)

    李星梅; 张素芳; 王旭锋; 乞建勋

    2008-01-01

    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.

  10. Preoperative shunts in thalamic tumours.

    Directory of Open Access Journals (Sweden)

    Goel A

    2000-10-01

    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. Evaluation of Intrapulmonary Shunt Alterations at Different Oxygen Concentrations and Oxygenation Parameters

    Directory of Open Access Journals (Sweden)

    Zerrin Demirtürk

    2015-06-01

    Full Text Available Aim: The aim of the current study was to evaluate the relationship of intrapulmonary shunt with FiO2 alterations in patients treated with mechanical ventilation in intensive care unit for extrapulmonary disorders. Also, we aimed to assess the role of correlation between shunt ratio and PaO2/FiO2, PaO2/PAO2, P(A-a O2 values in determining the treatment strategies. Methods: Twenty patients between ages of 19 and 75 years, requiring mechanical ventilation were enrolled into the study. We excluded two patients due to congestive heart failure and two patients due to acute respiratory distress syndrome (ARDS. Shunt fraction, P(A-aO2, PaO2/FiO2, PaO2/PAO2 values were calculated at each FiO2 level for each patient. Results: The lowest median shunt value was measured at FiO2: 0.3 There was a significant correlation between shunt values at FiO2 0.5 and 0.7 (r=0.850. The highest mean value of P(A-aO2 was measured at FiO2: 1 (382.91±106.46, and the lowest value of P(A-aO2 was measured at FiO2: 0.21 (38.64±16.97. PaO2/FiO2 and PaO2/PAO2 ratios measured at FiO2: 0.3 and 0.5 were found to be statistically significant. Conclusion: In this study, we have shown increased shunt fraction at FiO2: 1 level. Different oxygenation indices and shunt measurements give us important and useful knowledge about the patients’ current condition. (The Medical Bulletin of Haseki 2015; 53:124-9

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

    Science.gov (United States)

    Inampudi, Ravi; Gordeuk, John

    2016-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Chidambaram B

    2000-10-01

    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.

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

    LENUS (Irish Health Repository)

    Abubaker, Khalid

    2012-02-01

    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%).

  15. Severe respiratory failure following ventriculopleural shunt

    Directory of Open Access Journals (Sweden)

    Shahzad Alam

    2015-01-01

    Full Text Available Cerebrospinal fluid (CSF diversion procedure has been used for long to treat hydrocephalus in children. The principle of shunting is to establish a communication between the CSF and a drainage cavity (peritoneum, right atrium, and pleura. Ventriculoperitoneal shunt is used most commonly, followed secondly by ventriculopleural shunt (VPLS. Hydrothorax due to excessive CSF accumulation is a rare complication following both the type of shunts and is more frequently seen with VPLS. We report a case of a 6-year-old female child presenting with massive CSF hydrothorax with respiratory failure following VPLS. The aim of the article is to highlight early recognition of this rare and life-threatening condition, which could easily be missed if proper history is not available.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-12-15

    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.)

  17. Mesoatrial shunt in Budd-Chiari syndrome

    Directory of Open Access Journals (Sweden)

    Mirković Darko

    2009-01-01

    Full Text Available Background. Budd-Chiari syndrome (BCS represents partial or total occlusion of the hepatic veins with or without simultaneous obstruction of vena cava inferior (VCI. The symptoms of BCS are abdominal pain, hepatomegaly, ascites, varices of the abdominal wall, sometimes bleeding from the upper part of gastointestinal tract (GIT, lower limbs swelling and jaundice. Primary BSC is a relatively rare condition occurring in one per 100 000 of the population worldwide. Case report. A male patient, 25-year-old, facing tooth postextraction complications, was presented with acute BCS. On admission, physical examination revealed pale-grayish complexion, more pronounced veins over the thorax and abdomen, ascites, enlarged liver rising 8 cm below the right costal arch and having a minor pleural effusion by the right side. The patient was submitted to Doppler sonography and computed tomography (CT that verified the right leg deep veins thrombosis, as well as the presence of a thrombus in the intrahepatic portion of the VCI. Multislice computed tomography (MSCT showed occlusion of hepatic veins (Budd-Chiari syndrome and thrombosis of the VCI in the retrohepatic part 6 cm long. Also, increased values of transaminases and gamma GT and reduced values of albumines and serum ferrum were registered. Molecular examination revealed Factor V Leiden mutation - heterozygote. After preoperative preparations a mesocaval shunt was made using Gore- Tex ring graft of 12 mm. Intraoperatively, the blue enlarged liver was found with almost black zones of tense capsule. After a graft making, liver congestion decreased followed by the change of colour and volume. Within postoperative course metabolic and synthetic liver functions were obvious. Conclusion. In patients with BCS medicamentous treatment does not yield adequate results, but even causes worsening of general condition. Surgical therapy in the presented patient was performed timely regarding the stage of the disease due to

  18. Temporary intravascular shunts for peripheral vascular trauma.

    Directory of Open Access Journals (Sweden)

    Husain A

    1992-04-01

    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.

  19. Aneurysmal portosystemic venous shunt: a case report.

    Science.gov (United States)

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

    1999-10-01

    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.

  20. Classification system for reporting events involving human malfunctions

    International Nuclear Information System (INIS)

    The report describes a set of categories for reporting industrial incidents and events involving human malfunction. The classification system aims at ensuring information adequate for improvement of human work situations and man-machine interface systems and for attempts to quantify ''human error'' rates. The classification system has a multifacetted non-hierarchical structure and its compatibility with Ispra's ERDS classification is described. The collection of the information in general and for quantification purposes are discussed. 24 categories, 12 of which being human factors-oriented, are listed with their respective subcategories, and comments are given. Underlying models of human data process and their typical malfuntions and of a human decision sequence are described. The work reported is a joint contribution to the CSNI Group of Experts on Human Error Data and Assessment

  1. Cell shunt resistance and photovoltaic module performance

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  2. Ventriculoperitoneal shunt in cryptococcal meningitis with hydrocephalus.

    Science.gov (United States)

    Tang, L M

    1990-05-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Amit Singh

    2013-01-01

    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.

    LENUS (Irish Health Repository)

    Abubaker, Khalid

    2011-02-01

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

    Directory of Open Access Journals (Sweden)

    Shahram Shahsavaran

    2012-01-01

    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.

  6. Simulation model for port shunting yards

    Science.gov (United States)

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

    2016-08-01

    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.

  7. Neurogenic pulmonary edema due to ventriculo-atrial shunt dysfunction: a case report

    OpenAIRE

    Ana Sofia Cruz; Sónia Menezes; Maria Silva

    2016-01-01

    ABSTRACT BACKGROUND AND OBJECTIVES: Pulmonary edema is caused by the accumulation of fluid within the air spaces and the interstitium of the lung. Neurogenic pulmonary edema is a clinical syndrome characterized by the acute onset of pulmonary edema following a significant central nervous system insult. It may be a less-recognized consequence of raised intracranial pressure due to obstructive hydrocephalus by blocked ventricular shunts. It usually appears within minutes to hours after the in...

  8. 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

    Institute of Scientific and Technical Information of China (English)

    高莉莉

    2007-01-01

    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、

  9. Defective Homocysteine Metabolism: Potential Implications for Skeletal Muscle Malfunction

    Directory of Open Access Journals (Sweden)

    Suresh C. Tyagi

    2013-07-01

    Full Text Available Hyperhomocysteinemia (HHcy is a systemic medical condition and has been attributed to multi-organ pathologies. Genetic, nutritional, hormonal, age and gender differences are involved in abnormal homocysteine (Hcy metabolism that produces HHcy. Homocysteine is an intermediate for many key processes such as cellular methylation and cellular antioxidant potential and imbalances in Hcy production and/or catabolism impacts gene expression and cell signaling including GPCR signaling. Furthermore, HHcy might damage the vagus nerve and superior cervical ganglion and affects various GPCR functions; therefore it can impair both the parasympathetic and sympathetic regulation in the blood vessels of skeletal muscle and affect long-term muscle function. Understanding cellular targets of Hcy during HHcy in different contexts and its role either as a primary risk factor or as an aggravator of certain disease conditions would provide better interventions. In this review we have provided recent Hcy mediated mechanistic insights into different diseases and presented potential implications in the context of reduced muscle function and integrity. Overall, the impact of HHcy in various skeletal muscle malfunctions is underappreciated; future studies in this area will provide deeper insights and improve our understanding of the association between HHcy and diminished physical function.

  10. Connecting Malfunctioning Glial Cells and Brain Degenerative Disorders

    Directory of Open Access Journals (Sweden)

    Natalie Kaminsky

    2016-06-01

    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.

  11. Circadian malfunctions in depression - neurobiological and psychosocial approaches.

    Science.gov (United States)

    Nechita, Florina; Pîrlog, Mihail Cristian; ChiriŢă, Anca Livia

    2015-01-01

    Depression leads to disturbances in physiological rhythms, which result in disturbances in circadian sleep-wake cycles, hormonal secretion patterns and fluctuations in mood, all of which can be objectively measured. These disturbances, which are associated with depression, can be also used to define depression. Beyond these "transversal" time-related symptoms, there are the "longitudinal" time-related symptoms, since depression evolves over a long period of time, with a profound impact on a person's life and is often associated with long-term psychosocial consequences (Mendlewicz, 2010). The circadian rhythm reflects an approximate 24-hour cycle in the biochemical, physiological and behavioral processes of living entities, which crucially influences human well-being and health. Increasing evidence from clinical and neurobiological research suggests that disrupted temporal organization impairs behavior, cognition, mood, sleep and social activity and may be implicated in mental disorders. It has been proposed that circadian malfunction is a major core feature of mood disorders, depression in particular. In depressed patients, circadian rhythms and homeostatic processes are disrupted, thereby affecting mood, sleep, activity and a variety of biological functions such as hormone secretion and body temperature (Hajak & Landgrebe, 2010). Sleep difficulties are among the most current symptoms in depressed patients. Insomnia is often the reason why depressed patients seek help and relief of sleep disturbance may encourage compliance with antidepressant treatment. Apart from the discomfort that sleep problems produce, they may lead to exhaustion, poor functioning and they are associated with an increase in suicide risk (Wilson et al., 2013). PMID:26662127

  12. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt

    Science.gov (United States)

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

    2015-01-01

    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. Delayed otogenic pneumocephalus complicating ventriculoperitoneal shunt

    Directory of Open Access Journals (Sweden)

    Francesco Pieri

    2011-01-01

    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.

  14. A canine model of multiple portosystemic shunting.

    Science.gov (United States)

    Howe, L M; Boothe, H W; Miller, M W; Boothe, D M

    2000-01-01

    The objective of this study was to develop and describe an experimental canine model of multiple acquired portosystemic shunts (PSS) similar in nature to spontaneously occurring PSS. Sixteen dogs were used and were divided into a control (n = 6) and a diseased group (n = 10). Dogs of the diseased group were administered dimethylnitrosamine (2 mg/kg of body weight, po) twice weekly, and clinicopathologic, ultrasonographic, and hepatic scintigraphic findings were recorded during the development of hepatic disease and PSS. Surgery was then performed to permit visual verification of multiple shunts, catheter placement for portography examination, and biopsy of the liver. All diseased dogs developed severe hepatic disease and multiple PSS as documented visually at surgery and on portography. Based on this study, dimethylnitrosamine-induced portosystemic shunting appears to be an appropriate model for spontaneously occurring multiple PSS secondary to portal hypertension. PMID:10741951

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

    Science.gov (United States)

    Ouattara, N; Mlynski, A; Pierret, C

    2011-10-01

    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.

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

    DEFF Research Database (Denmark)

    Høgsberg, Jan; Krenk, Steen

    2012-01-01

    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...

  17. Right-to-left shunt with hypoxemia in pulmonary hypertension

    OpenAIRE

    2009-01-01

    Background: Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting. Methods: To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO(2) < 10 kPa), shunt fraction (Qs/Qt) grea...

  18. Distal splenorenal shunt with partial spleen resection

    Directory of Open Access Journals (Sweden)

    Gajin Predrag

    2007-01-01

    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

  19. 21 CFR 882.4545 - Shunt system implantation instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shunt system implantation instrument. 882.4545... implantation instrument. (a) Identification. A shunt system implantation instrument is an instrument used in the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing...

  20. Aberrant gene expression in dogs with portosystemic shunts

    NARCIS (Netherlands)

    van Steenbeek, F.G.; van den Bossche, L.; Grinwis, G.C.M.; Kummeling, A.; Gils, I.H.; Koerkamp, M.G.; van Leenen, D.; Holstege, F.C.; Penning, L.C.; Rothuizen, J.; Leegwater, P.A.J.; Spee, B.

    2013-01-01

    Abstract Congenital portosystemic shunts are developmental anomalies of the splanchnic vascular system that cause portal blood to bypass the liver. Large-breed dogs are predisposed for intrahepatic portosystemic shunts (IHPSS) and small-breed dogs for extrahepatic portosystemic shunts (EHPSS). While

  1. An unusual case of intrahepatic portosystemic venous shunt

    Directory of Open Access Journals (Sweden)

    Pumersha Naidoo

    2013-06-01

    Full Text Available Intrahepatic portosystemic venous shunts are rare vascular anomalies that may be detected in asymptomatic patients, given the recent advances in radiological imaging techniques. Accurate shunt evaluation and classification can be performed with ultrasound and multi-detector computed tomography. We report an unusual case of an intrahepatic portosystemic venous shunt with an incidental finding of neurofibroma.

  2. 49 CFR 236.104 - Shunt fouling circuit.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  3. An expert system for sensor data validation and malfunction detection

    International Nuclear Information System (INIS)

    Nuclear power plant operation and monitoring in general is a complex task which requires a large number of sensors, alarms and displays. At any instant in time, the operator is required to make a judgment about the state of the plant and to react accordingly. During abnormal situations, operators are further burdened with time constraints. The possibility of an undetected faulty instrumentation line, adds to the complexity of operators' reasoning tasks. Failure of human operators to cope with the conceptual complexity of abnormal situations often leads to more serious malfunctions and further damages to plant (TMI-2 as an example). During these abnormalities, operators rely on the information provided by the plant sensors and associated alarms. Their usefulness however, is quickly diminished by their large number and the extremely difficult task of interpreting and comprehending the information provided by them. The need for an aid to assist the operator in interpreting the available data and diagnosis of problems is obvious. Recent work at the Ohio State University Laboratory of Artificial Intelligence Research (LAIR) and the nuclear engineering program has concentrated on the problem of diagnostic expert systems performance and their applicability to the nuclear power plant domain. There has also been concern about the diagnostic expert systems performance when using potentially invalid sensor data. Because of this research, an expert system has been developed that can perform diagnostic problem solving despite the existence of some conflicting data in the domain. This work has resulted in enhancement of a programming tool, that allows domain experts to create a diagnostic system that will be to some degree, tolerant of bad data while performing diagnosis. This expert system is described here

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

    OpenAIRE

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

    2016-01-01

    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.

  5. Muzzle shunt augmentation of conventional railguns

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.V.

    1990-01-01

    Augmentation is a well-known technique for reducing the armature current and hence the armature power dissipation in a plasma armature railgun. In spite of the advantages, no large augmented railguns have been built, primarily due to the mechanical and electrical complexity introduce by the extra conductors required. It is possible to achieve some of the benefits of augmentation in conventional railgun by diverting a fraction {phi} of the input current through a shunt path at the muzzle of the railgun. In particular, the relation between force and armature current is the same as that obtained in an n-turn, series connected augmented railgun with n = 1/(1-{phi}). The price of this simplification is a reduction in electrical efficiency and some additional complexity in the external electrical system. Additions to the electrical system are required to establish the shunt current and to control its magnitude during projectile acceleration. The relationship between muzzle shunt augmentation and conventional series augmentation is developed and various techniques is developed and various techniques for establishing and controlling the shunt current are illustrated with a practical example. 5 refs., 8 figs., 2 tabs.

  6. Laparoscopic management of complicated ventriculoperitoneal shunts

    Directory of Open Access Journals (Sweden)

    Jain S

    2003-04-01

    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.

  7. ARTIFICIAL SHUNTING OF CEREBROSPINAL-FLUID

    NARCIS (Netherlands)

    HOEKSTRA, A

    1994-01-01

    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

  8. Treatment of syringomyelia with a syringosubarachnoid shunt.

    Science.gov (United States)

    Tator, C H; Briceno, C

    1988-02-01

    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.

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

    Science.gov (United States)

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

    2016-09-01

    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. PMID:27581319

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

    Science.gov (United States)

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

    2016-09-01

    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.

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

    Science.gov (United States)

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

    2012-10-01

    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.

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

    Science.gov (United States)

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

    2016-06-01

    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.

  13. 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

    Directory of Open Access Journals (Sweden)

    L. Crespo

    2007-11-01

    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.

  14. Unidirectional valve malfunction by the breakage or malposition of disc - two cases report -

    OpenAIRE

    Lee, Chol; Lee, Kyu Chang; Kim, Hye Young; Kim, Mi Na; Choi, Eun Kyung; Kim, Ji-Sub; Lee, Won Sang; Lee, Myeong Jong; Kim, Hyung Tae

    2013-01-01

    Malfunction of the unidirectional valve in a breathing circuit system may cause hypercapnia from the rebreathing of expired gas, ventilation failure, and barotrauma. Capnography is a useful method for monitoring the integrity of the unidirectional valve. We experienced two cases of malfunction of a unidirectional valve which caused leakage and reverse flow, diagnosed early as a change of the capnographic waveform. One case was caused by expiratory unidirectional valve breakage. The other was ...

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

    Directory of Open Access Journals (Sweden)

    Ferrarese Alessia

    2016-08-01

    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.

  16. Intraparenchymal pericatheter cyst following disconnection of ventriculoperitoneal shunt system

    Directory of Open Access Journals (Sweden)

    S Balasubramaniam

    2013-01-01

    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.

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

    Science.gov (United States)

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

    2015-07-17

    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%).

  18. A fluid level in an acute extradural haematoma

    Energy Technology Data Exchange (ETDEWEB)

    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))

    1994-01-01

    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.)

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

    Science.gov (United States)

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

    2016-01-01

    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.

  20. Nitrogen heat pipe for cryocooler thermal shunt

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1995-09-01

    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.

  1. Dc SQUIDs with asymmetric shunt resistors

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2013-07-01

    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.

  2. Portacaval Shunt for Portal Hypertensive Gastropathy

    Directory of Open Access Journals (Sweden)

    John Craig Collins

    1997-01-01

    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.

  3. Quantitative evaluation fo cerebrospinal fluid shunt flow

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

    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 ..mu..Ci 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.

  4. Shunt current loss of the vanadium redox flow battery

    Science.gov (United States)

    Xing, Feng; Zhang, Huamin; Ma, Xiangkun

    The shunt current loss is one of main factors to affect the performance of the vanadium redox flow battery, which will shorten the cycle life and decrease the energy transfer efficiency. In this paper, a stack-level model based on the circuit analog method is proposed to research the shunt current loss of the vanadium redox flow battery, in which the SOC (state of charge) of electrolyte is introduced. The distribution of shunt current is described in detail. The sensitive analysis of shunt current is reported. The shunt current loss in charge/discharge cycle is predicted with the given experimental data. The effect of charge/discharge pattern on the shunt current loss is studied. The result shows that the reduction of the number of single cells in series, the decrease of the resistances of manifold and channel and the increase of the power of single cell will be the further development for the VRFB stack.

  5. Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

    Science.gov (United States)

    Owen, Joshua M; Gaba, Ron Charles

    2016-01-01

    Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or 50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance.

  6. Effect of peritoneo-venous shunt on portal pressure.

    OpenAIRE

    Samanta, A K; Leevy, C. M.

    1989-01-01

    The cause of variceal bleed after a peritoneo-venous shunt is not known. Portal haemodynamic consequences of a peritoneo-venous shunt are poorly understood. The most critical period after a peritoneo-venous shunt is the early postoperative period when rapid mobilisation of peritoneal fluid occurs. Serial changes in the portal pressure during the early postoperative period have not been recorded. In the present study preoperative wedge hepatic vein (WHV), right atrial (RA) and pulmonary capill...

  7. Medulloblastoma: seeding of VP shunt tract and peritoneum

    OpenAIRE

    David Pettersson; Schmitz, Kelli R.; Pollock, Jeffrey M.; Katharine L. Hopkins

    2012-01-01

    We report on a 5-year-old boy with seeding of the peritoneum and a ventriculoperitoneal shunt tract by anaplastic medulloblastoma. The role of ventriculoperitoneal shunting in the spread of primary central nervous system tumors has been controversial. In the case reported here, the unique distribution of tumor implants on ultrasound and multiplanar computed tomography gives further credence to the argument that ventriculoperitoneal shunting is a pathway for extraneural metastases of primary c...

  8. Major complication after intrauterine vesico-amniotic shunting

    Directory of Open Access Journals (Sweden)

    Springer Alexander

    2010-01-01

    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.

  9. Semi-shunt field emission in electronic devices

    Science.gov (United States)

    Karpov, V. G.; Shvydka, Diana

    2014-08-01

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  10. Semi-shunt field emission in electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Karpov, V. G., E-mail: victor.karpov@utoledo.edu [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Shvydka, Diana, E-mail: diana.shvydka@utoledo.edu [Department of Radiation Oncology, University of Toledo, Toledo, Ohio 43606 (United States)

    2014-08-04

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  11. Superconducting fault current-limiter with variable shunt impedance

    Science.gov (United States)

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    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.

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

    Science.gov (United States)

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

    2015-08-01

    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.

  13. Embolization of severe arterioportal shunts in the patients with hepatocellular carcinoma : safety and influence on patient survival

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Deok Hee; Yoon, Hyun Ki; Song, Ho Young; Kim, Gab Choul; Hwang, Jae Cheol; Sung, Kyu Bo [Asan Medical Center, Ulsan Univ. College of Medicine, Ulsan (Korea, Republic of)

    1999-12-01

    To evaluate the safety and the influence of embolization of severe arterioportal shunts, and the effect of the procedure on the survival rate of patients with hepatocellular carcinoma combined with portal vein tumor thrombosis. This study involved a total of 54 patients with hepatocellular carcinoma in whom hepatic arteriography revealed severe arterioportal shunt. From among this total, 34 patients (embolization group) underwent chemoinfusion after shunt embolization, while 19 (control group) underwent chemoinfusion only. The embolic materials included PVA particles and /or Gelfoam pieces. The frequency of postem-bolization symptoms (Chi-squared test) and changes in laboratory values (paired t-test) were compared between the two groups, and shunt improvement was also evaluated. Patient survival was tested using the Kaplan-Meier method. Fever and RUQ pain were more frequent in the embolization group (p<0.001). The complications of embolization included severe postembolization syndrome (n=1), acute hepatic failure (n=2), hepatic infarction (n=1), and sepsis (n=1). There were no significant changes in laboratory values. Among the 28 patients (24 of embolization group and four of control group) who underwent follow-up angiography, arterioportal shunt became less severe or disappeared in ten of the embolization group. For the embolization and control groups, the mean survival interval was 29.5{+-}5.4 weeks and 10.3{+-}3.1 weeks (p=0.0002), respectively. The best results were seen in the PVA particle group (p=0.01). The embolization of severe arterioportal shunts is relatively safe and increases patient survival rate.

  14. Embolization of severe arterioportal shunts in the patients with hepatocellular carcinoma : safety and influence on patient survival

    International Nuclear Information System (INIS)

    To evaluate the safety and the influence of embolization of severe arterioportal shunts, and the effect of the procedure on the survival rate of patients with hepatocellular carcinoma combined with portal vein tumor thrombosis. This study involved a total of 54 patients with hepatocellular carcinoma in whom hepatic arteriography revealed severe arterioportal shunt. From among this total, 34 patients (embolization group) underwent chemoinfusion after shunt embolization, while 19 (control group) underwent chemoinfusion only. The embolic materials included PVA particles and /or Gelfoam pieces. The frequency of postem-bolization symptoms (Chi-squared test) and changes in laboratory values (paired t-test) were compared between the two groups, and shunt improvement was also evaluated. Patient survival was tested using the Kaplan-Meier method. Fever and RUQ pain were more frequent in the embolization group (p<0.001). The complications of embolization included severe postembolization syndrome (n=1), acute hepatic failure (n=2), hepatic infarction (n=1), and sepsis (n=1). There were no significant changes in laboratory values. Among the 28 patients (24 of embolization group and four of control group) who underwent follow-up angiography, arterioportal shunt became less severe or disappeared in ten of the embolization group. For the embolization and control groups, the mean survival interval was 29.5±5.4 weeks and 10.3±3.1 weeks (p=0.0002), respectively. The best results were seen in the PVA particle group (p=0.01). The embolization of severe arterioportal shunts is relatively safe and increases patient survival rate

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

    DEFF Research Database (Denmark)

    Klokker, Mads; Vesterhauge, Søren

    2013-01-01

    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...... and consequently treat patients more efficiently. This brief overview describes the benefit of Epley's Omniax Chair, video head impulse tests and the Vestibular Autorotation Test. The need for vestibular rehabilitation programmes and for a closer collaboration between physicians and the social authorities...

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

    Directory of Open Access Journals (Sweden)

    Vachha Behroze

    2005-11-01

    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.

  17. Neurogenic pulmonary edema due to ventriculo-atrial shunt dysfunction: a case report

    Directory of Open Access Journals (Sweden)

    Ana Sofia Cruz

    2016-04-01

    Full Text Available ABSTRACT BACKGROUND AND OBJECTIVES: Pulmonary edema is caused by the accumulation of fluid within the air spaces and the interstitium of the lung. Neurogenic pulmonary edema is a clinical syndrome characterized by the acute onset of pulmonary edema following a significant central nervous system insult. It may be a less-recognized consequence of raised intracranial pressure due to obstructive hydrocephalus by blocked ventricular shunts. It usually appears within minutes to hours after the injury and has a high mortality rate if not recognized and treated appropriately. CASE REPORT: We report a patient with acute obstructive hydrocephalus due to ventriculo-atrial shunt dysfunction, proposed to urgent surgery for placement of external ventricular drainage, who presented with neurogenic pulmonary edema preoperatively. She was anesthetized and supportive treatment was instituted. At the end of the procedure the patient showed no clinical signs of respiratory distress, as prompt reduction in intracranial pressure facilitated the regression of the pulmonary edema. CONCLUSIONS: This report addresses the importance of recognition of neurogenic pulmonary edema as a possible perioperative complication resulting from an increase in intracranial pressure. If not recognized and treated appropriately, neurogenic pulmonary edema can lead to acute cardiopulmonary failure with global hypoperfusion and hypoxia. Therefore, awareness of and knowledge about the occurrence, clinical presentation and treatment are essential.

  18. Train shunting at a workshop area

    DEFF Research Database (Denmark)

    Jacobsen, Per Munk; Pisinger, David

    2011-01-01

    We consider the problem of planning the shunting of train units at a railway workshop area. Before and after the maintenance check, a train unit is parked at a depository track. The problem is to schedule the trains to workshops and depot tracks in order to complete the repairs as soon as possible......, while avoiding train blockings at the tracks. We give a formal definition of the problem and present three heuristic approaches based on, respectively, Guided Local Search (GLS), Guided Fast Local Search (GFLS) and Simulated Annealing (SA). Computational experiments are reported for realistic instances...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  20. Epidural hematoma after ventriculoperitoneal shunt surgery: report of two cases

    Directory of Open Access Journals (Sweden)

    PEREIRA CARLOS UMBERTO

    1998-01-01

    Full Text Available Ventriculoperitoneal shunt operations represent the most used choice for treating hydrocephalus, although some related complications have been reported. Due to its rarity, potential dangers, and mortality rate, we present two cases of epidural hematoma following ventriculoperitoneal shunt, discussing its pathophysiology and prophylaxis.

  1. Analysis of generator bearing vibration data for diagnosing rotor circuit malfunction in DFIGs

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Sweeney, Christian W.; Jensen, Bogi Bech;

    2014-01-01

    the slip ring unit and the rotor circuit is manifested as excessive vibration seen in both ends of the generator. The consistent and accurate diagnosis of a rotor circuit malfunction is of crucial importance in regards to proper troubleshooting of the fault and the overall health of the generator...

  2. Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks

    Science.gov (United States)

    Müller, Martin; Hirschfeld, Julian; Lambertz, Rita; Schulze Lohoff, Andreas; Lustfeld, Hans; Pfeifer, Heinz; Reißel, Martin

    2014-12-01

    In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

    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.

  4. Baclofen overdose from possible intrinsic malfunction of SynchroMed II pump.

    Science.gov (United States)

    Davanzo, Justin R; Rizk, Elias

    2015-08-01

    This is a case report illustrating an overdose of baclofen in a 10-year-old boy due to a likely malfunction of a SynchroMed II pump. This ultimately necessitated a pump replacement. One-year follow-up showed no further incidents of baclofen overdose, with multiple pump refills. PMID:25978532

  5. Malfunctioned and Fractured Penile Prosthesis Caused by Cross Placement: Case Report

    Directory of Open Access Journals (Sweden)

    Nihat Karakoyunlu

    2015-05-01

    Full Text Available Penile prosthesis is a functional option for patients who have erectile dysfunction after failed medical and intracavernosal treatments. Malleable penile prosthesis is a good alternative. Penile prosthesis implantation is a surgical process. Seldomly complications occur. In this study we presented a 61 y old man who has malfunctioned and broken penile prosthesis due to cross implantation.

  6. Malfunctioned and Fractured Penile Prosthesis Caused by Cross Placement: Case Report

    OpenAIRE

    Nihat Karakoyunlu; Sercan Sarı; Harun Ozdemir; Hikmet Topaloglu; Ugur Ozok; Levent Sagnak; Hamit Ersoy

    2015-01-01

    Penile prosthesis is a functional option for patients who have erectile dysfunction after failed medical and intracavernosal treatments. Malleable penile prosthesis is a good alternative. Penile prosthesis implantation is a surgical process. Seldomly complications occur. In this study we presented a 61 y old man who has malfunctioned and broken penile prosthesis due to cross implantation.

  7. Percutaneous peritoneovenous shunt positioning: technique and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2002-05-01

    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.)

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

    Science.gov (United States)

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

    2010-07-01

    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.

  9. Ventriculoperitoneal shunt infection with Listeria innocua.

    Science.gov (United States)

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

    2014-08-01

    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.

  10. Flexural waves focusing through shunted piezoelectric patches

    Science.gov (United States)

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

    2016-07-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-03-17

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2007-03-01

    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.

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

    Science.gov (United States)

    Sotelo, Julio

    2012-01-01

    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. PMID:22530174

  14. Portosystemic Shunt Surgery in Patients with Idiopathic Noncirrhotic Portal Hypertension.

    Science.gov (United States)

    Karagul, Servet; Yagci, Mehmet Ali; Tardu, Ali; Ertugrul, Ismail; Kirmizi, Serdar; Sumer, Fatih; Isik, Burak; Kayaalp, Cuneyt; Yilmaz, Sezai

    2016-01-01

    BACKGROUND Idiopathic noncirrhotic portal hypertension (INCPH) is a rare disease characterized by increased portal venous pressure in the absence of cirrhosis and other causes of liver diseases. The aim of the present study was to present our results in using portosystemic shunt surgery in patients with INCPH. MATERIAL AND METHODS Patients who had been referred to our Liver Transplantation Institute for liver transplantation and who had undergone surgery from January 2010 to December 2015 were retrospectively analyzed. Patients with INCPH who had undergone portosystemic shunt procedure were included in the study. Age, sex, symptoms and findings, type of portosystemic shunt, and postoperative complications were assessed. RESULTS A total of 1307 patients underwent liver transplantation from January 2010 to December 2015. Eleven patients with INCPH who did not require liver transplantation were successfully operated on with a portosystemic shunt procedure. The mean follow-up was 30.1±19 months (range 7-69 months). There was no mortality in the perioperative period or during the follow-up. Two patients underwent surgery again due to intra-abdominal hemorrhage; one had bleeding from the surgical site except the portacaval anastomosis and the other had bleeding from the h-graft anastomosis. No patient developed encephalopathy and no patient presented with esophageal variceal bleeding after portosystemic shunt surgery. Shunt thrombosis occurred in 1 patient (9.9%). Only 1 patient developed ascites, which was controlled medically. CONCLUSIONS Portosystemic shunt surgery is a safe and effective procedure for the treatment of patients with INCPH. PMID:27194018

  15. Muzzle shunt augmentation of conventional railguns

    Energy Technology Data Exchange (ETDEWEB)

    Parker, J.V. (Los Alamos National Lab., NM (United States). Physics Div.)

    1991-01-01

    This paper reports on augmentation which is a technique for reducing the armature current and hence the armature power dissipation in a plasma armature railgun. In spite of the advantages, no large augmented railguns have been built, primarily due to the mechanical and electrical complexity introduced by the extra conductors required. it is possible to achieve some of the benefits of augmentation in a conventional railgun by diverting a fraction {phi} of the input current through a shunt path at the muzzle of the railgun. In particular, the relation between force and armature current is the same as that obtained in an n-turn, series-connected augmented railgun with n = 1/(1 {minus} {phi}). The price of this simplification is a reduction in electrical efficiency and some additional complexity in the external electrical system.

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

    Science.gov (United States)

    Banks, B. A. (Inventor)

    1983-01-01

    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.

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

    Science.gov (United States)

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

    2016-10-01

    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. PMID:27347804

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

    Science.gov (United States)

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

    2016-10-01

    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.

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

    DEFF Research Database (Denmark)

    Ren, Guanjiao; Chen, Weihai; Dasgupta, Sakyasingha;

    2015-01-01

    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...... 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...... 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...

  20. Comparison of Common Methods in Dynamic Response Predictions of Rotor Systems with Malfunctions

    OpenAIRE

    Hongliang Yao; Qian Zhao; Qi Xu; Bangchun Wen

    2014-01-01

    The efficiency and accuracy of common time and frequency domain methods that are used to simulate the response of a rotor system with malfunctions are compared and analyzed. The Newmark method and the incremental harmonic balance method are selected as typical representatives of time and frequency domain methods, respectively. To improve the simulation efficiency, the fixed interface component mode synthesis approach is combined with the Newmark method and the receptance approach is combined ...

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

    Directory of Open Access Journals (Sweden)

    Kowalski Jerzy

    2016-01-01

    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.

  2. Effects of acute normovolemic hemodilution on intrapulmonary shunting and oxygenation during one-lung ventilation in dogs%急性等容血液稀释对犬单肺通气期间肺分流与氧合的影响

    Institute of Scientific and Technical Information of China (English)

    马宁; 李树人; 槐庆元

    2001-01-01

    目的观察犬单肺通气期间,不同程度急性等容血液稀释对肺分流和氧供、氧耗等的影响.方法 12只健康杂种犬,基础麻醉后插入双腔气管导管,股动、静脉置管.稳定30分钟(HD0)后,以血定安等速置换全血,分别达到轻度(HDl)、中度(HD2)、重度(HD3)和极重度(HD4)血液稀释四个阶段.每阶段均分为双肺通气(TLV)和单肺通气(OLV),分别于各阶段TLV、OLVl5分钟后测量分流(Qs/Qt)及氧供(DO2)、氧耗(VO2)等各指标变化.结果随着HD程度的加深,平均动脉压、心输出量、肺血管阻力(PVR)、平均肺动脉压(MPAP)、氧分压、DO2等趋于降低,氧摄取率(ERO2)、血乳酸、Qs/Qt趋于增加,到HD3、HD4时已出现DO2-VO2依赖性降低及无氧酵解征象.与TLV时相比,OLV期间HD0、HD1及HD2组PVR、MPAP增高明显(P<0.01),而HD3、HD4组变化不大(P>0.05);OLV时QS/Qt增加更为明显,HD2、HD3及HD4组分别较基值增加74%、164%及177%(P<0.01).结论缺氧、ANHD均为影响Qs/Qt与氧合的重要因素,OLV时ANHD应以不低于中度为准.%Objective To evaluate the effects of different degrees of acute normovolemic hemodilution (ANH) on intrapulmonary shunting, oxygen delivery and consumption during one-lung ventilation(OLV) in dogs. Methods Twelve healthy mongrel dogs weighing 18-22 kg were anesthetized with Ⅳ pentobarbital sodium 20mg.kg-1, scopolamine 0.3 mg and pancuronium 0.2 mg. kg-1 and intubated with a left-sided Carlen' s tube. Correct positioning of the tube was verified by auscultation and by visual inspection after thoracotomy at the end of the experiment. The dogs were mechanically ventilated with 100% oxygen. PET CO2 was maintained between 4.67-6.00 kPa. ECG and rectal temperature were continuously monitored. An intravenous line was established for infusion of Lacted Ringer solution. SwanGanz catheter was inserted via femoral vein on one side for sampling of mixed venous blood and measurement of cardiac output (CO) by

  3. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Science.gov (United States)

    2010-04-01

    ...) Identification. A peritoneo-venous shunt is an implanted device that consists of a catheter and a pressure activated one-way valve. The catheter is implanted with one end in the peritoneal cavity and the other in...

  4. [A simple peritoneovenous shunt in the treatment of chronic ascites].

    Science.gov (United States)

    Pafko, P; Hladík, P

    2001-02-01

    The authors describe their own initial experience with a peritoneo-venous shunt in otherwise incurable ascites. It is a simple procedure which is more satisfactory than the formerly used technique of implantation of Le Veen's system. PMID:12881921

  5. [Sapheno-peritoneal shunt for the treatment of ascites].

    Science.gov (United States)

    Nagy, Z; Gyurkovics, E; Kaliszky, P; Kupcsulik, P

    2001-08-01

    For the surgical treatment of drug resistant ascites caused by hepatic cirrhosis usually different types of valvular plastic tubes are used, implanted as peritoneo-venous shunts. These shunts drain the ascites into the jugular vein. In the 1st Surgical Department of the Semmelweis University Budapest we have performed 267 peritoneo-venous shunt operations. We introduced a new method using an autolog venous graft with a peritoneo-venous anastomosis, that drains the ascites into the saphenous, then femoral vein. So far we performed 5 such interventions. The early results suggest that sapheno-peritoneal shunt can be successfully used for treatment of ascites. With this operation complications of plastic grafts are avoidable. PMID:11550492

  6. A case of breast cancer involving a ventriculoperitoneal shunt.

    Science.gov (United States)

    Kamei, Mirei; Kikuchi, Nobuyuki; Ichimura, Homare; Chujo, Masao; Takahashi, Yoshiaki; Sugio, Kenji

    2016-12-01

    An 84-year-old woman was examined for an enlargement of an induration in the left breast. A ventriculoperitoneal shunt had been placed for postoperative normal pressure hydrocephalus of a cerebral hemorrhage, and it had penetrated the mass according to the computed tomography findings. Breast cancer was diagnosed after a close examination; however, close observation was selected because her family rejected treatment. She developed somnolence 7 months after the initial examination, and ventricular dilatation and expansion of the low-density region around the ventricle were noted on computed tomography, suggesting that the enlarged tumor had excluded the shunt and caused obstruction. The growth of breast carcinoma involving a shunt tube can be the cause of obstruction of a ventriculoperitoneal shunt. Our findings suggest that a breast lesion should be evaluated at both pre- and postoperation. PMID:26943684

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

    Science.gov (United States)

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

    2015-01-01

    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.

  8. In vitro flow measurements in ion sputtered hydrocephalus shunts

    Science.gov (United States)

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

    1989-01-01

    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.

  9. Aberrant gene expression in dogs with portosystemic shunts.

    Directory of Open Access Journals (Sweden)

    Frank G van Steenbeek

    Full Text Available Congenital portosystemic shunts are developmental anomalies of the splanchnic vascular system that cause portal blood to bypass the liver. Large-breed dogs are predisposed for intrahepatic portosystemic shunts (IHPSS and small-breed dogs for extrahepatic portosystemic shunts (EHPSS. While the phenotype resulting from portal bypass of the liver of the two types of shunt is identical, the genotype and molecular pathways involved are probably different. The aim of this study was to gain insight into the pathways involved in the different types of portosystemic shunting. Microarray analysis of mRNA expression in liver tissue from dogs with EHPSS and IHPSS revealed that the expression of 26 genes was altered in either IHPSS or EHPSS samples compared with that in liver samples from control dogs. Quantitative real-time PCR of these genes in 14 IHPSS, 17 EHPSS, and 8 control liver samples revealed a significant differential expression of ACBP, CCBL1, GPC3, HAMP, PALLD, VCAM1, and WEE1. Immunohistochemistry and Western blotting confirmed an increased expression of VCAM1 in IHPSS but its absence in EHPSS, an increased WEE1 expression in IHPSS but not in EHPSS, and a decreased expression of CCBL1 in both shunt types. Regarding their physiologic functions, these findings may indicate a causative role for VCAM1 in EHPSS [corrected] and WEE1 for IHPSS. CCBL1 could be an interesting candidate to study not yet elucidated aspects in the pathophysiology of hepatic encephalopathy.

  10. First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii

    Directory of Open Access Journals (Sweden)

    Jonathan Baghdadi

    2015-01-01

    Full Text Available Fungal infections in the central nervous system (CNS are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt.

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

    Directory of Open Access Journals (Sweden)

    Babak ABDINIA

    2013-02-01

    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

  12. A Novel Technique for Laparoscopic Salvage of CAPD Catheter Malfunction and Migration: The Santosh-PGI Hanging Loop Technique

    Directory of Open Access Journals (Sweden)

    Santosh Kumar

    2015-01-01

    Full Text Available CAPD catheter malfunction is a common problem. Obstruction due to wrapping by appendices epiploicae of sigmoid colon has been rarely reported in literature. We report a case of CAPD catheter malfunction caused by catheter tip migration and obstruction by appendices epiploicae that was successfully managed by laparoscopic hanging loop technique. This case report highlights the ease with which epiplopexy can be performed and catheter tip migration can be prevented by this innovative laparoscopic procedure.

  13. Reducing CSF shunt placement in patients with spinal myelomeningocele

    Directory of Open Access Journals (Sweden)

    Suresh Sankhla

    2009-01-01

    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

  14. 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

    Institute of Scientific and Technical Information of China (English)

    许启霞; 詹庆元; 王辰; 庞宝森; 李一鸣

    2008-01-01

    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

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

    DEFF Research Database (Denmark)

    Rasmussen, J.

    1982-01-01

    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....

  16. Multidisciplinary team malfunctioning on a state hospital unit: a case study.

    Science.gov (United States)

    Gomez, E A; Ruiz, P; Langrod, J

    1980-01-01

    The use of multidisciplinary teams in the care of psychiatric patients can be countertherapeutic unless attention is paid to the dynamics of team functioning. The authors present a case study of team malfunctioning on an inpatient unit in a state hospital that resulted from staff's role confusion and insecurity. Patient care was relegated to second place as major interpersonal conflicts among the staff were played out along ethnic and cultural lines. Resolution of the conflicts required identifying their source, clarifying staff roles, and initiating a special inservice training program focused primarily on the needs of paraprofessional staff. PMID:7353821

  17. Laparoscopy for ventriculoperitoneal shunt implantation and revision surgery

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

    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.

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

    Science.gov (United States)

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

    2013-07-30

    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.

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

    Science.gov (United States)

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

    1982-04-01

    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.

  20. [Massive endocardial thrombosis in a patient with a peritoneo-jugular shunt for refractory ascites: the therapeutic success of tissue plasminogen activator and defibrotide].

    Science.gov (United States)

    Sacchetti, C; Pederzoli, S; Tamborrino, E; Grandi, M

    1994-01-01

    The authors report a case of a patient with a refractory ascites due to extrahepatic portal thrombosis in course of idiopathic thrombocythemia. A peritoneovenous shunt was applied and as a late complication a massive thrombosis of the intracardiac portion of the duct developed. Thrombolysis was obtained with tissue plasminogen activator at doses usually administered for acute myocardial infarction. Prophylaxis of recurrence was pursued with pictomide and defibrotide. PMID:8079040

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2003-06-01

    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.

  2. Association of distinct intracranial pial and dural arteriovenous shunts

    Energy Technology Data Exchange (ETDEWEB)

    Vilela, P. [Neuroradiology Dept., Garcia de Orta Hospital (Portugal); Brugge, K. ter; Willinsky, R. [Toronto Western Hospital, Div. of Neuroradiology, Toronto, ON (Canada)

    2001-09-01

    Intracranial pial and dural arteriovenous shunts may exist at different sites in the same patient. The etiology, natural history and treatment of these associated conditions have not been completely determined. We reviewed the records of 765 cases of pial arteriovenous malformation and 137 dural arteriovenous fistulae and malformations. We selected eight patients with both pial and dural arteriovenous shunts, separate anatomically, with distinct feeding arteries and draining veins, representing 1 % of pial and 17 % of dural shunts. Presentation was related to the dural lesion in 5 cases (62.5 %) and to the pial malformation in three (37.5 %). Treatment of these lesions should be considered separately based on their angioarchitecture and natural history. (orig.)

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

    Directory of Open Access Journals (Sweden)

    M. Berardengo

    2016-01-01

    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.

  4. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    Science.gov (United States)

    Er, Uygur; Akyol, Çetin; Bavbek, Murad

    2016-01-01

    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

  5. Endovascular occlusion of high-flow intracranial arteriovenous shunts: technical note

    OpenAIRE

    van Rooij, Willem Jan; Sluzewski, Menno

    2007-01-01

    Endovascular closure of high-flow arteriovenous (AV) shunts in intracranial AV malformations or pial fistulas is technically challenging. In this paper, we illustrate two simple methods to occlude large high-flow AV shunts in a controlled manner.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-15

    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.

  8. Different degree in proteasome malfunction has various effects on root growth possibly through preventing cell division and promoting autophagic vacuolization.

    Directory of Open Access Journals (Sweden)

    Xianyong Sheng

    Full Text Available The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated proteins using immunofluorescence labeling, and autophagy activity using LysoTracker and MDC. The results indicated that lower concentration of proteasome inhibitors promoted root growth, whereas higher concentration of inhibitors had the opposite effects. The accumulation of cyclin B was linked to MG132-induced decline in meristem size, indicating that proteasome malfunction prevented cell division. Besides, MG132-induced accumulation of the ubiquitinated proteins was associated with the increasing fluorescence signal of LysoTracker and MDC in the elongation zone, revealing a link between the activation of autophagy and proteasome malfunction. These results suggest that weak proteasome malfunction activates moderate autophagy and promotes cell elongation, which compensates the inhibitor-induced reduction of cell division, resulting in long roots. Whereas strong proteasome malfunction induces severe autophagy and disturbs cell elongation, resulting in short roots.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-01-01

    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.

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

    Science.gov (United States)

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

    2011-06-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Deepak, E-mail: deepakjain02@yahoo.com; Arora, Ankur, E-mail: aroradrankur@yahoo.com [Institute of Liver and Biliary Sciences, Department of Radiology (India); Deka, Pranjal, E-mail: drpranjaldeka@gmail.com [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India); Mukund, Amar, E-mail: dramarmukund@gmail.com; Bhatnagar, Shorav, E-mail: drshorav@yahoo.com [Institute of Liver and Biliary Sciences, Department of Radiology (India); Jindal, Deepti, E-mail: deepijindal@rediffmail.com; Kumar, Niteen, E-mail: drniteenkumar@gmail.com; Pamecha, Viniyendra, E-mail: viniyendra@yahoo.co.uk [Institute of Liver and Biliary Sciences, Department of Hepatopancreatobiliary Surgery (India)

    2013-08-01

    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.

  12. Cryptococcal cerebrospinal fluid shunt infection treated with fluconazole

    Directory of Open Access Journals (Sweden)

    Daniel Eymard

    1993-01-01

    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.

  13. CSF shunts 50 years on--past, present and future.

    Science.gov (United States)

    Drake, J M; Kestle, J R; Tuli, S

    2000-11-01

    Cerebrospinal fluid (CSF) shunts were invented almost 50 years ago. While their introduction revolutionized the treatment of hydrocephalus, their complications have become legendary, and the focus of much investigation and development of new devices. New devices have been based upon improved understanding of the pathophysiology of hydrocephalus or shunt complications. Despite the rational, or frequently "more physiological," functioning of these devices, all too often unexpected complications have ensued, and the initial enthusiasm for the devices has waned. Assessing the efficacy of the devices has been difficult, owing to the lack of properly conducted studies. Nevertheless, the overall impact of shunt design improvements has seemed very limited. A recent randomized trial of CSF shunt design, examining the failure rates of two new and widely used valves (the Cordis Orbis Sigma and the Medtronic PS Medical Delta valves) failed to find any advantage of these over standard valve designs, many of which have been used almost since the inception of CSF shunts. A search for risk factors for failure, in a post hoc analysis of the data, indicated only that the etiology of the hydrocephalus and the position and local environment of the ventricular catheter tip were probably important. Remarkably, the rate of change in the size of the ventricles and the final ventricular size were not different despite the substantial differences in flow characteristics of the two new valves. Shunt failure rates of less than 5% at 1 year, with infection rates of less than 1%, seem like reasonable goals for the next decade in the new millenium. This can be achieved through basic research into the pathophysiology of shunt failure with improved mathematical models, and perhaps animal models of shunt failure. Efficacy of new devices or treatments must be scrutinized scientifically so as not to waste valuable resources and time on unproven treatments. Uncontrolled series and testimonial

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    1992-07-01

    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.).

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

    @@ 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.

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

    LENUS (Irish Health Repository)

    Lim, C

    2012-02-03

    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.

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

    Science.gov (United States)

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

    2015-07-01

    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.

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

    NARCIS (Netherlands)

    Szatmári, V.

    2004-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    R Pourkhalili

    2005-09-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2015-10-15

    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.

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

    International Nuclear Information System (INIS)

    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

  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

    Directory of Open Access Journals (Sweden)

    Ronaldo André Poerschke

    2012-03-01

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

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [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)

    2013-11-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Taslakian, Bedros, E-mail: btaslakian@gmail.com [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Faraj, Walid, E-mail: wf07@aub.edu.lb [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: mk12@aub.edu.lb [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: mk00@aub.edu.lb [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: fe19@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Saade, Charbel, E-mail: cs39@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon); Hallal, Ali, E-mail: ah05@aub.edu.lb [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: ah24@aub.edu.lb [Department of Radiology, American University of Beirut Medical Center, Riad El-Solh 1107 2020—PO Box: 11-0236, Beirut (Lebanon)

    2015-08-15

    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. Wideband digital phase comparator for high current shunts

    CERN Document Server

    Pogliano, Umberto; Serazio, Danilo

    2011-01-01

    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...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    The magnetic shunt is generally inserted in a planar transformer to increase the leakage inductance which can be utilized as the series inductor in resonant circuits such as the LLC resonant converter. This paper presents a calculation methodology for the leakage inductance of the transformer...... and the experimental results have proven the validity of the proposed calculation method for leakage inductance....

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    The magnetic shunt is generally inserted in a planar transformer to increase the leakage inductance which can be utilized as the series inductor in resonant circuits such as the LLC resonant converter. This paper presents a calculation methodology for the leakage inductance of the transformer...... and the experimental results have proven the validity of the proposed calculation method for leakage inductance....

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

    NARCIS (Netherlands)

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

    2001-01-01

    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

  9. Congenital extrahepatic portosystemic shunt associated with heterotaxy and polysplenia

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2010-07-15

    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.)

  10. Comparison of passive inductor designs for piezoelectric shunt damping

    Science.gov (United States)

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

    2016-04-01

    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.

  11. Shunted-Josephson-junction model. I. The autonomous case

    DEFF Research Database (Denmark)

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

    1977-01-01

    The shunted-Josephson-junction model: the parallel combination of a capacitance, a phase-dependent conductance, and an ideal junction element biased by a constant current, is discussed for arbitrary values of the junction parameters. The main objective is to provide a qualitative understanding of...

  12. Peritoneo-vulvar catheter extrusion after shunt operation.

    Science.gov (United States)

    Nagulic, M; Djordjevic, M; Samardzic, M

    1996-04-01

    We report an unusual case of catheter extrusion through the external genitalia. between the labium majus and the labium minus, in a 6-month-old hydrocephalic baby. The event occurred 5 months after placement of a ventriculoperitoneal shunt. PMID:8739410

  13. Large area shunt defect free GaAs solar cells

    International Nuclear Information System (INIS)

    Shunt defects have been found to be the type of defect that can degrade and cause failure in GaAs solar cells. Because of their catastrophic effects, it is necessary to insure that no shunt defects are formed in the solar cell. A technique for fabricating large area shunt defect free GaAs solar cells has been investigated. A Be doped GaAlAs window layer was grown directly on a n-type GaAs substrate by isothermal liquid phase epitaxial growth (ILPE). By growing directly on the GaAs substrate and not growing the usual buffer, absorber, collector, and window layer combination, the fabrication is simplified and yields can be large. It was found that the Be from the liquid GaAlAs melt diffused into the GaAs to form a complete collector layer. Because the collector is complete, a shunt defect free solar cell is produced. The results of the ILPE growth are reported for both 5.1 cm2 and 0.12 cm2 solar cells. The technique is very versatile and may be used to fabricate larger area solar cells

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    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.

  15. Multidetector row CT study of percutaneous transhepatic intrahepatic portosystemic shunt

    International Nuclear Information System (INIS)

    Objective: To investigate imaging features of the liver, portal vein and hepatic vein or transhepatic inferior vena cava in patients with severe liver cirrhosis in multidetector row computed tomography (MDCT), and assess the feasibility, safety and clinical significance of percutaneous transhepatic intrahepatic portosystemic, shunt (PTIPS). Methods: Fifty patients with severe liver cirrhosis confirmed by clinical data and imaging examination were enrolled in this study. Simulation of intrahepatic portosystemic shunt by percutaneous transhepatic, approach is as follows. The right midaxillary line (the eighth oi ninth intercostal space) was selected as puncture point A the right branch of portal vein was puncture point B, transhepatic inferior vena cava was puncture point C, and the distal part of right portal vein was D. A-B-C connection is simulated as percutaneous transhepatic puncture tract, C-B-D connection is simulated as portosystemic shunt tract. After tri-phase contrast-enhanced CT scanning, postprocessing images through multiple planner reconstruction (MPR) were obtained. The data were indicated statistically by x-bar±s. And 9.5% confidence interval for mean was calculated. Anatomic relationship among the right portal vein, transhepatic inferior vena cava, hepatic artery and bile duct were analyzed for all patients. Results: The length of the needle (A-B-C) is (145.7±14.8) mm. The curvature of the needle (the angle of A-B line and B-C line) is (145.0±9.9) . The length of transhepatic shunt tract (B-C) is (42.7±7.2) mm. The length of the shunt tract (C-B-D) is (117.7±11.6) mm; The angle of the shunt tract (the angle of B-C line and B-D line) is (108.5±5.9)°. In 24/50 patients, transhepatic inferior vena cava locate in the dorsal of the right portal vein, in 26/50 patients they are in the same plane. In all patients, the right branches of hepatic artery and bile duct locate in the ventral of the right portal vein. Conclusion: The procedure of PTIPS is

  16. Inferior vena cava stent grafting closure of a high-flow portacaval shunt.

    Science.gov (United States)

    Alhaizaey, Abdullah; Ghanekar, Anand; Oreopoulos, George

    2016-01-01

    Portacaval (PC) shunts can be of congenital or acquired types. Acquired PC shunts are usually created in patients with end-stage liver disease to manage complications associated with portal hypertension or may be part of selected adult-adult living donor liver transplantation procedures to decrease the chance of the small-for-size syndrome. The main potential complication of these acquired high-flow PC shunts is early hepatic encephalopathy. We present a case of a high-flow acquired PC shunt after liver transplantation that was complicated by uncontrolled encephalopathy. This was treated by endovascular inferior vena cava stent grafting for shunt closure. PMID:26946901

  17. Comparison of Common Methods in Dynamic Response Predictions of Rotor Systems with Malfunctions

    Directory of Open Access Journals (Sweden)

    Hongliang Yao

    2014-01-01

    Full Text Available The efficiency and accuracy of common time and frequency domain methods that are used to simulate the response of a rotor system with malfunctions are compared and analyzed. The Newmark method and the incremental harmonic balance method are selected as typical representatives of time and frequency domain methods, respectively. To improve the simulation efficiency, the fixed interface component mode synthesis approach is combined with the Newmark method and the receptance approach is combined with the incremental harmonic balance method. Numerical simulations are performed for rotor systems with single and double frequency excitations. The inherent characteristic that determines the efficiency of the two methods is analyzed. The results of the analysis indicated that frequency domain methods are suitable single and double frequency excitation rotor systems, whereas time domain methods are more suitable for multifrequency excitation rotor systems.

  18. Aging and malfunction of valves in CANDU special safety systems. Phase 1

    International Nuclear Information System (INIS)

    Aging and wear related valve malfunctions have been reported in American nuclear generating systems. This report documents the first attempt to study these phenomena on a global basis in Canadian nuclear power plants. A general methodology outlines an approach to this type of study which is amenable to use within existing information structures. Nuclear regulatory requirements which influence the testing of valves in Canadian nuclear power plants are reviewed. The reporting systems which emanate from these requirements are discussed and sources of valve failure data are reviewed. It is determined that modifications to existing failure reporting systems are required before practical means of collecting data necessary for the analysis of age related valve malfunctions can be developed. In spite of limitations in reported failure data, a partial data base is compiled for valve failures in Special Safety Systems of domestic nuclear plants. Data are reported for the period 1982 to 1986. The valve population and basic parameters of each valve such as type, operator, function, etc., and the reported failures against this population are compiled and reviewed for evidence of time dependent versus random failure trends. Results suggest that there is no clear age related failure trend. In fact, some systems and stations, experienced a reduction in failure rates with years of servicing, suggesting that some earlier generic valve problems may have been solved. Present inspection, test, and maintenance practices are reviewed and their effectiveness for purposes of predicting or preventing incipient failures is assessed to be of moderate value. Modern failure prevention methods are highlighted and their applicability discussed

  19. Right-to-left shunt with hypoxemia in pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Mastroïanni Bénédicte

    2009-03-01

    Full Text Available Abstract Background Hypoxemia is common in pulmonary hypertension (PH and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL shunting. Methods To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO2 2 (AaPO2, and with transthoracic contrast echocardiography performed within 3 months. Results Among 263 patients with precapillary PH, 34 patients were included: pulmonary arterial hypertension, 21%; PH associated with lung disease, 47% (chronic obstructive pulmonary disease, 23%; interstitial lung disease, 9%; other, 15%; chronic thromboembolic PH, 26%; miscellaneous causes, 6%. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 45.8 ± 10.8 mmHg, 2.2 ± 0.6 L/min/m2, and 469 ± 275 dyn.s.cm-5, respectively. PaO2 in room air was 6.8 ± 1.3 kPa. Qs/Qt was 10.2 ± 4.2%. AaPO2 under 100% oxygen was 32.5 ± 12.4 kPa. Positive contrast was present at transthoracic contrast echocardiography in 6/34 (18% of patients, including only 4/34 (12% with intracardiac RL shunting. Qs/Qt did not correlate with hemodynamic parameters. Patients' characteristics did not differ according to the result of contrast echocardiography. Conclusion When present in patients with precapillary PH, RL shunting is usually not related to reopening of patent foramen ovale, whatever the etiology of PH.

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

    Science.gov (United States)

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

    2014-09-01

    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.

  1. Experimental comparison of piezoelectric and magnetostrictive shunt dampers

    Science.gov (United States)

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

    2016-04-01

    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.

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

    Science.gov (United States)

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

    2016-03-01

    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.

  3. Lumboatrial shunt in a patient with Crouzon syndrome complicated by pseudotumor cerebri.

    Science.gov (United States)

    Sankey, Eric W; Khattab, Mohamed H; Elder, Benjamin D; Goodwin, C Rory; Rekate, Harold L; Rigamonti, Daniele

    2015-09-01

    A 25-year-old man with Crouzon syndrome complicated by pseudotumor cerebri and multiple shunt failures presented with progressive back and neck pain, intermittent headaches, and associated vomiting secondary to shunt infection. Due to his previous history of repeated failure of both ventriculoperitoneal and lumboperitoneal (LP) shunting procedures, the decision was made to place a lumboatrial (LA) shunt via an approach through the internal jugular vein. The procedure was uncomplicated and the man's symptoms were relieved. Despite significant improvement, the LA shunt limited his exercise tolerance, and as an avid runner and weight lifter, he requested reconversion back to an LP shunt. At a follow-up of 20months, he continued to do well both clinically and radiographically. This case report summarizes the successful placement and use of an LA shunt for the treatment of intracranial hypertension in the setting of Crouzon syndrome. PMID:26021731

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

    Directory of Open Access Journals (Sweden)

    Sridhar K

    2009-01-01

    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.

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

    Science.gov (United States)

    Brooks, Andre

    2014-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Angelo Luiz Maset

    2014-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Procop Gary

    2008-10-01

    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.

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

    NARCIS (Netherlands)

    Schirmann, Felix

    2013-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    Leanne M. Hirshfield

    2014-01-01

    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.

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

    Science.gov (United States)

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

    2015-08-01

    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.

  11. Cerebral venous thrombosis after ventriculoperitoneal shunting: a case report.

    Science.gov (United States)

    Matsubara, Teppei; Ayuzawa, Satoshi; Aoki, Tsukasa; Ikeda, Go; Shiigai, Masanari; Matsumura, Akira

    2014-01-01

    Ventriculoperitoneal shunting (VPS) is a simple procedure, but there are several potential complications. We describe the first reported case of cerebral venous thrombosis (CVT) after VPS. A 69-year-old man suffering from normal pressure hydrocephalus underwent left VPS. Two months later he developed CVT and cerebral venous hemorrhage in the left frontal lobe. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed the thrombus formation just adjacent to the shunt tube. One possible cause is compression of the cortical vein after brain shift and/or tension of the cortical vein due to intracranial hypotension. A protein C deficiency was also detected. Surgeons should be aware that cerebral venous thrombosis can occur after VPS. PMID:24257484

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

    Directory of Open Access Journals (Sweden)

    Benicio Oton de Lima

    2014-07-01

    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.

  13. [Surgical treatment of refractory ascites with peritoneovenous shunt].

    Science.gov (United States)

    Massari, R; Fulgente, R; Marinelli, S; Romessis, M

    1995-01-01

    Leveen and associates described a peritoneo-venous shunt which proved to be useful in patients with intractable ascites. Medical therapy, paracentesis and peritoneovenous shunt have been compared, but there is uncertainty about their relative merits. Therefore, the leveen device has be placed in last years in an increasing number of patients: it has not been shown by prospective trials to prolong survival significantly, although it may shorten hospitalization and improve the quality of life. A number of early and late complications were described but they do not influence the general results: origin and features of such complications are discussed as well as their prevention and treatment and personal cases are presented. Selection of patients and careful surgical procedure seems to be mandatory for better results. PMID:8706187

  14. Could there be light at the end of the tunnel? Mesocaval shunting for refractory esophageal varices in patients with contraindications to transjugular intrahepatic portosystemic shunt.

    Science.gov (United States)

    Davis, Jessica; Chun, Albert K; Borum, Marie L

    2016-07-01

    Cirrhotic patients with recurrent variceal bleeds who have failed prior medical and endoscopic therapies and are not transjugular intrahepatic portosystemic shunt candidates face a grim prognosis with limited options. We propose that mesocaval shunting be offered to this group of patients as it has the potential to decrease portal pressures and thus decrease the risk of recurrent variceal bleeding. Mesocaval shunts are stent grafts placed by interventional radiologists between the mesenteric system, most often the superior mesenteric vein, and the inferior vena cava. This allows flow to bypass the congested hepatic system, reducing portal pressures. This technique avoids the general anesthesia and morbidity associated with surgical shunt placement and has been successful in several case reports. In this paper we review the technique, candidate selection, potential pitfalls and benefits of mesocaval shunt placement. PMID:27429715

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

    Science.gov (United States)

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

    2012-11-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Thomas W. Faust

    1997-01-01

    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.

  17. Transjugular Intrahepatic Portosystemic Shunts in Patients with Hepatic Malignancy

    OpenAIRE

    Wallace, Michael J.; Madoff, David C.

    2005-01-01

    Since its first clinical application in 1988, the transjugular intrahepatic portosystemic shunt (TIPS) has emerged as a safe and effective means of managing patients with morbid portal hypertension. Despite the considerable body of literature on TIPS, portal decompression in patients with malignancy has not been sufficiently examined. These patients typically experience sequelae of portal hypertension that requires palliation. The purpose of this article is to review the reported experience w...

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

    Institute of Scientific and Technical Information of China (English)

    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

    2010-01-01

    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...

  19. Distal Splenorenal Shunt for Portal Vein Thrombosis after Liver Transplantation

    OpenAIRE

    Marino, Ignazio R.; Esquivel, Carlos O.; Zajko, Albert B.; Malatack, Jeffrey; Scantlebury, Velma P.; Shaw, Byers W.; Starzl, Thomas E.

    1989-01-01

    A 17-yr-old female received a liver transplant for type I glycogen storage disease. A year later, when she experienced variceal gastrointestinal hemorrhage, an angiogram revealed thrombosis of the portal vein with hepatopetal collateral channels. A distal splenorenal shunt was performed because of failure of sclerotherapy to control subsequent bleeding episodes and the fact that the liver function was normal. This patient continues to have normal hepatic function with a patent splenorenal shu...

  20. Parallel Piezoelectric Shunt Damping of Rotationally Periodic Structures

    Directory of Open Access Journals (Sweden)

    Bilal Mokrani

    2015-01-01

    Full Text Available This paper considers the RL shunt damping of rotationally periodic structures with an array of regularly spaced piezoelectric patches. The technique is targeted to the damping of a specific mode with n nodal diameters. For this particular case, one can take advantage of the shape of the targeted mode to organize the piezoelectric patches as a modal filter (in parallel loops which reduces the demand on the inductors of the tuned inductive shunt. In the case of a perfectly rotationally periodic structure, it is possible to organize 4n piezoelectric transducers (PZT patches in two parallel loops of 2n patches each. In this way, the demand on the inductors is reduced by 4n2 as compared to independent loops, which may allow a fully passive integration of the RL shunt in a turbomachinery application. The method is first illustrated experimentally on a circular plate; it is then applied to a prototype of an industrial bladed drum. The influence of blade mistuning is investigated.

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

    Directory of Open Access Journals (Sweden)

    Jinbing Zhao

    2015-03-01

    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.

  2. Minimally invasive ventriculo-atrial shunt for hydrocephalus

    Institute of Scientific and Technical Information of China (English)

    李江山; 江勇豪; 程成; 张世凯

    2005-01-01

    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.

  3. Negative impedance shunted electromagnetic absorber for broadband absorbing: experimental investigation

    International Nuclear Information System (INIS)

    The traditional tuned mass absorber is widely employed to control the vibration of a primary structure by transferring the vibrating energy to the absorber. However, the working band of the absorber is very narrow, which limits the application of broadband vibration control. This study presents a novel broadband electromagnetic absorber by first introducing two negative impedance shunts to improve broadband damping of the absorber. The electromagnetic absorber is modeled, and the corresponding electromagnetic coupling coefficient is tested. A cantilever beam is employed to verify the broadband vibration absorption of the negative resistance (NR) shunted electromagnetic absorber (NR absorber) and the negative inductance NR shunted electromagnetic absorber (NINR absorber). The governing equations of the beam with two absorbers are derived, and the experiments are set up. The results point out that the NR and NINR absorbers can attenuate the broadband vibration. The proposed absorbers do not need the feedback system and the real-time controller compared to the active absorber; hence, they have great application potential in aerospace and in submarine applications, as well as in civil and mechanical engineering. (paper)

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

    Directory of Open Access Journals (Sweden)

    Ezequiel Gleichgerrcht

    2009-01-01

    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.

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

    Science.gov (United States)

    George, Crişan; Nicolae, Filip

    2014-06-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Kelsom Corey

    2012-11-01

    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.

  7. Immunopathology of giardiasis: the role of lymphocytes in intestinal epithelial injury and malfunction

    Directory of Open Access Journals (Sweden)

    AG Buret

    2005-03-01

    Full Text Available T lymphocyte-mediated pathogenesis is common to a variety of enteropathies, including giardiasis, cryptosporidiosis, bacterial enteritis, celiac's disease, food anaphylaxis, and Crohn's disease. In giardiasis as well as in these other disorders, a diffuse loss of microvillous brush border, combined or not with villus atrophy, is responsible for disaccharidase insufficiencies and malabsorption of electrolytes, nutrients, and water, which ultimately cause diarrheal symptoms. Other mucosal changes may include crypt hyperplasia and increased infiltration of intra-epithelial lymphocytes. Recent studies using models of giardiasis have shed new light on the immune regulation of these abnormalities. Indeed, experiments using an athymic mouse model of infection have found that these epithelial injuries were T cell-dependent. Findings from further research indicate that that the loss of brush border surface area, reduced disaccharidase activities, and increase crypt-villus ratios are mediated by CD8+ T cells, whereas both CD8+ and CD4+ small mesenteric lymph node T cells regulate the influx of intra-epithelial lymphocytes. Future investigations need to characterize the CD8+ T cell signaling cascades that ultimately lead to epithelial injury and malfunction in giardiasis and other malabsorptive disorders of the intestine.

  8. Implementing an Expert Diagnostic Assistance System for Car Failure and Malfunction

    Directory of Open Access Journals (Sweden)

    Salama A. Mostafa

    2012-03-01

    Full Text Available Applications in fault diagnosis are continuously being implemented to serve different sectors. Car failure detection is a sequence of diagnostic processes that necessitates the deployment of expertise. The Expert System (ES is one of the leading Artificial Intelligence (AI techniques that have been adopted to handle such task. This paper presents the imperatives for an ES in developing car failure detection model and the requirements of constructing successful Knowledge-Based Systems (KBS for such model. In addition, it exhibits the adaptation of the ES in the development of Car Failure and Malfunction Diagnosis Assistance System (CFMDAS. However, CFMDAS development faces many challenges such as collecting the required data for building the knowledge base and performing the inferencing. Furthermore, diagnosis of car faults requires high technical skills and experienced mechanics who are typically scarce and expensive to get. Thus, systems such as CFMDAS can be highly useful in assisting mechanics for failure detection and training purposes. Moreover, capturing and retaining valuable knowledge on such domain yield more accurate and less time consuming models.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  10. A RARE CASE OF BOWEL PERFORATION SECONDARY TO VENTRICULO PERITONEAL SHUNT

    Directory of Open Access Journals (Sweden)

    Aditya Pratap

    2014-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Fernanda O. de Carvalho

    2014-04-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gaba, Ron C., E-mail: rgaba@uic.edu [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)

    2012-12-15

    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.

  13. Evaluation of peritoneo-venous shunt patency with 99mTc-phytate

    International Nuclear Information System (INIS)

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5mCi of 99mTc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable in the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency. (Author)

  14. Evaluation of Peritoneo-venous Shunt Patency with {sup 99m}Tc-phytate

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Dal Young; Chung, June Key; Lee, Jong Suk; Lee, Chang Soo [National Medical Center, Seoul (Korea, Republic of)

    1985-09-15

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5 mCi of {sup 99m}Tc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable m the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency.

  15. Evaluation of Peritoneo-venous Shunt Patency with 99mTc-phytate

    International Nuclear Information System (INIS)

    A simple imaging procedure has been devised for patients with peritoneo-venous shunts when ascites reaccumulates and a decision must be made on whether or not to revise the shunt. We recently experienced a patient with reaccumulated ascites in whom obstruction of peritoneo-venous shunt was suspected. 5 mCi of 99mTc-phytate was injected into the peritoneal cavity and imaging of the abdomen was performed 1-30 minutes later. With a proper functioning shunt, radioactivity in the liver and spleen were easily identifiable in this case. If the shunt is obstructed, tracer activity will remain in the peritoneal cavity and thus can not be identifiable m the liver or spleen. Conclusively, radionuclide methods might be very useful for evaluation of peritoneo-venous shunt patency.

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

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; LIU Xiao-Ning; WANG Can

    2011-01-01

    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.

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

    Science.gov (United States)

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

    2014-09-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Le R

    2016-03-01

    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

  19. Multiple subdural abscesses following colonic perforation - a rare complication of a ventriculoperitoneal shunt

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, B.S.; Kak, V.K.

    1988-07-01

    A case of colonic perforation by a ventriculoperitoneal shunt, its subsequent migration and protrusion from the anal orifice is reported. The shunt reservoir and ventricular catheter were removed percutaneously, and the disconnected peritoneal catheter was pulled out through the anus. Blood culture grew Klebsiella pneumoniae and Streptococcus fecalis. CT scan showed multiple subdural abscesses with evidence of ventriculitis. Removal of the shunt (as described), evacuation of subdural pus and systemic antibiotics resulted in complete recovery.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

    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.

  1. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction

    OpenAIRE

    Suresh, Supraja; Black, Richard A

    2015-01-01

    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, t...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2007-06-15

    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

  3. 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)

    Energy Technology Data Exchange (ETDEWEB)

    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

    2007-05-15

    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.)

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

    Science.gov (United States)

    Le, Ryan; Gupta, Neeru

    2016-01-01

    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. PMID:27051320

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

    Science.gov (United States)

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

    2015-11-01

    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.

  6. Different Degree in Proteasome Malfunction Has Various Effects on Root Growth Possibly through Preventing Cell Division and Promoting Autophagic Vacuolization

    OpenAIRE

    Xianyong Sheng; Qian Wei; Liping Jiang; Xue Li; Yuan Gao; Li Wang

    2012-01-01

    The ubiquitin/proteasome pathway plays a vital role in plant development. But the effects of proteasome malfunction on root growth, and the mechanism underlying this involvement remains unclear. In the present study, the effects of proteasome inhibitors on Arabidopsis root growth were studied through the analysis of the root length, and meristem size and cell length in maturation zone using FM4-64, and cell-division potential using GFP fusion cyclin B, and accumulation of ubiquitinated protei...

  7. The structure of an expert system to diagnose and supply a corrective procedure for nuclear power plant malfunctions

    International Nuclear Information System (INIS)

    During the past two years, two prototype knowledge based systems have been developed at the Ohio State University. These systems were the result of collaboration between the Nuclear Engineering Program and the Laboratory for Artificial Intelligence Research (LAIR). The first system uses hierarchical classification to diagnose malfunctions of the coolant system in a General Electric Boiling Water Reactor (BWR). The second system provides a plan of action, through a process of dynamic procedure management, to stabilize the plant once an abnormal transient has occurred. The objective of this paper is to discuss the structure that has been designed to integrate the two systems. The combined system will be capable of informing plant personnel about the nature of malfunctions, and of supplying to the operator the most direct corrective procedure available. Two important features of the integrated system are faulty sensor detection, based on malfunction context and unlike sensor data, and procedure management based on the initial state of the plant. Since the two knowledge based systems were developed separately, the integration has required a separate component currently under development, the Plant Status Monitoring System (PSMS). The task of PSMS is to monitor plant parameters in order to detect an abnormal condition developing within the plant. Based on the nature of the event, PSMS is capable of directing control to either the procedure management or diagnosis component. The integrated system plays only an advisory role, and any suggested action would be executed by the plant personnel

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

    Science.gov (United States)

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

    2013-11-01

    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.

  9. Clinical results of the transjugular intrahepatic portosystemic shunt

    International Nuclear Information System (INIS)

    To evaluate the clinical results of transjugular intrahepatic portosystemic shunt(TIPS) for the control of variceal bleeding. TIPS creation was attempted in 23 patients with endoscopically confirmed variceal bleeding. Most patients had multiple episodes of bleeding in the past and have been treated with multiple endoscopic sclerotherapies. Pre-and post-procedural hepatic and portal vein pressures were measured. After creation of TIPS patients were followed up at regular intervals. TIPS has been successfully accomplished in 22 of 23 patients using Wallstent(n = 21) and Strecker stent(n = 1). Immediate bleeding control was achieved in all patients with shunt creation. No procedure-related complication was noted. Portal vein pressure was reduced from 30.7 ± 5.8 mmHg to 20.8 ± 4.7 mmHg. The mean pressure gradient of portosystemic shunt dropped from 22.8 ± 6.0 prior to TIPS to 12.2 ± 4.1 immediately after. During the follow-up period (6-556 days, mean; 10 months), seven patients died; progressive hepatic failure (n 4), variceal rebleeding (n = 2), and respiratory failure(n = 1). Hepatic encephalopathy after TIPS was noted in 7 patients(31.8%). Variceal rebleeding occurred in 3 patients(13.6%). The remaining 15 patients have survived an average of 11 months. This results suggest that TIPS is a safe and effective method for lowering portal pressure and controlling variceal bleeding. Furthermore if these initial results are encouraged by further long-term observation, TIPS could replace endoscopic and risky surgical intervention

  10. Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study.

    Science.gov (United States)

    Evin, Morgane; Guivier-Curien, Carine; Pibarot, Philippe; Kadem, Lyes; Rieu, Régis

    2016-05-01

    Malfunction of bileaflet mechanical heart valves in the mitral position could either be due to patient-prosthesis mismatch (PPM) or leaflet obstruction. The aim of this article is to investigate the validity of current echocardiographic criteria used for diagnosis of mitral prosthesis malfunction, namely maximum velocity, mean transvalvular pressure gradient, effective orifice area, and Doppler velocity index. In vitro testing was performed on a double activation left heart duplicator. Both PPM and leaflet obstruction were investigated on a St. Jude Medical Master. PPM was studied by varying the St. Jude prosthesis size (21, 25, and 29 mm) and stroke volume (70 and 90 mL). Prosthesis leaflet obstruction was studied by partially or totally blocking the movement of one valve leaflet. Mitral flow conditions were altered in terms of E/A ratios (0.5, 1.0, and 1.5) to simulate physiologic panel of diastolic function. Maximum velocity, effective orifice area, and Doppler velocity index are shown to be insufficient to distinguish normal from malfunctioning St. Jude prostheses. Doppler velocity index and effective orifice area were 1.3 ± 0.49 and 1.83 ± 0.43 cm(2) for testing conditions with no malfunction below the 2.2 and 2 cm(2) thresholds (1.19 cm(2) for severe PPM and 1.23 cm(2) for fully blocked leaflet). The mean pressure gradient reached 5 mm Hg thresholds for several conditions of severe PPM only (6.9 mm Hg and mean maximum velocity value: 183.4 cm/s) whereas such value was never attained in the case of leaflet obstruction. In the case of leaflet obstruction, the maximum velocity averaged over the nine pulsed-wave Doppler locations increased by 38% for partial leaflet obstruction and 75% for a fully blocked leaflet when compared with normal conditions. Current echocardiographic criteria might be suboptimal for the detection of bileaflet mechanical heart valve malfunction. Further developments and investigations are required in order

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

    Directory of Open Access Journals (Sweden)

    Moisés Heleno Vieira Braga

    2009-06-01

    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.

  12. Shunting arc plasma source for pure carbon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2012-02-15

    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{sup 2} at the peak of the pulse.

  13. LCL Interface Filter Design for Shunt Active Power Filters

    Directory of Open Access Journals (Sweden)

    DOBRICEANU, M.

    2010-08-01

    Full Text Available This paper is focused on finding the parameters of a second order interface filter connected between the power system and the shunt active filter based on switching frequency of the active filter. Many publications on power active filters include various design methods for the interface inductive filter which take into account the injected current and its dynamic. Compared to these ones, the approach presented in this paper is oriented toward the design of the interface filter starting from filter transfer functions by imposing the performances of the filter.

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

    Science.gov (United States)

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

    2012-02-01

    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.

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

    Science.gov (United States)

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

    2012-02-01

    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.

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

    Science.gov (United States)

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

    2012-02-01

    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. PMID:22380206

  17. [PERITONEAL VENOUS SHUNT IN THE TREATMENT OF MALIGNANTASCITIS: PRELIMINARY REPORT

    Science.gov (United States)

    Brazzini, Augusto; Cantella, Raúl

    1998-01-01

    The present study, mentions the use of a valve for the drainage os ascitic fluid, better known as the peritoneo venous shunt, as a paliation treatment in terminal oncologic patients. It was performed in four patients with diseminated carcinomas, of diferent primary ethiology. These patients had a bad life quality, because when admitted in our Radiology suite, the clinical examination showed shortness of breathearly saciety, lethargy, and were found handiccapped to perform their habitual skills. This is a short and preliminar series, but it is an encouraging report, because, the quality of life, our goal, is improved. PMID:12209221

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

    DEFF Research Database (Denmark)

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

    1977-01-01

    . The mathematical discussion makes use of the phase-space representation of the solutions to the differential equation. The behavior of the trajectories in phase space is described for different characteristic regions in parameter space and the associated features of the junction IV curve to be...... expected are pointed out. The main objective is to provide a qualitative understanding of the junction behavior, to clarify which kinds of properties may be derived from the shunted-junction model, and to specify the relative arrangement of the important domains in the parameter-space decomposition....

  19. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    OpenAIRE

    Chen, Yu-Wei; Wu, Yu-Te; Lin, Jhin-Shyaun; Yang, Wu-Chang; Hsu, Yung-Ho; Lee, Kuo-Hua; Ou, Shou-Ming; Chen, Yung-Tai; Shih, Chia-Jen; Lee, Pui-Ching; Chan, Chia-Hao; Chung, Ming-Yi; Lin, Chih-Ching

    2016-01-01

    Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a m...

  20. Shunt currents in vanadium flow batteries: Measurement, modelling and implications for efficiency

    Science.gov (United States)

    Fink, H.; Remy, M.

    2015-06-01

    Shunt currents are an important factor which must be considered when designing a stack for flow batteries. They lead to a reduction of the coulombic efficiency and can cause furthermore a critical warming of the electrolyte. Shunt currents inevitably appear at bypass connections of the hydraulic system between the single cells of a stack. In this work the shunt currents of a five-celled mini stack of a vanadium flow battery with external hydraulic system and their effects are investigated directly. The external hydraulic system allows the implementation of current sensors for direct measurement of the shunt currents; moreover, the single bypass channels can be interrupted by clamping the tube couplings and with it the shunt currents between the cells when the pumps are off. Thus the shares of losses by cross contamination and by shunt currents are quantified separately by charge conservation measurements. The experimentally gained data are compared to a shunt current model based on a equivalent circuit diagram and the linear equation system derived from it. Experiments and model data are in good agreement. The effects of shunt currents for different flow frame geometries and number of cells in a stack are simulated and presented in this work.

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

    Science.gov (United States)

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    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.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Black, P.M.

    1982-02-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Vikas Kumar

    2016-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Abbas Amirjamshidi

    2015-01-01

    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.

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

    Science.gov (United States)

    Miyake, Hiroji

    2016-05-15

    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.

  7. Evaluation of LeVeen-shunt patency using Tc-99m labelled macroaggregated albumin.

    Science.gov (United States)

    Adil, Allah Rakha; Waqar, Amin

    2005-12-01

    A LeVeen peritoneo-venous shunt is placed for intractable ascites. Determination of obstruction site in the shunt tube is a difficult problem. We describe a simple nuclear medicine method using 111MBq (3mCi) of Technetium-99m labeled macro-aggregated albumin injected intraperitoneally. PMID:16398982

  8. Quantitative Evaluation of Arteriovenous Shunts of the Brain Under Clinical and Experimental Conditions

    International Nuclear Information System (INIS)

    With the help of a new quantitative method to evaluate shunt function, quantitative evaluations of arteriovenous shunt were carried out on patients with traumatic shunts between the internal carotid artery and the cavernous sinus and with arteriovenous haemangiomata. These indicated that, in traumatic arteriovenous fistulas, up to 90% of the blood from the internal carotid is shunted into the cavernous sinus. In patients with arteriovenous haemangiomata shunt flow ranged from 30 to 7%. Post-operatively, both the cerebral blood flow (measured by 133Xe) and the shunt flow showed a return to normal. Shunt function was also evaluated in 28 test animals, their cerebral blood flow having previously been studied, using 133Xe. Six cats formed a control group, the remaining 22 being divided into two groups of 11 animals each. Respiratory acidosis was induced in one group and respiratory alkalosis in the other. The results revealed that the shunt flow was reduced in acidosis (mean 18.26%) and increased in alkalosis (mean 50.1%). In normal animals it averaged 29.4%. (author)

  9. Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children

    Science.gov (United States)

    Ramos, Theresa N.; Arynchyna, Anastasia A.; Blackburn, Tessa E.; Johnston, James M.

    2016-01-01

    BACKGROUND. Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection. METHODS. CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients. RESULTS. Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection. CONCLUSION. Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection. FUNDING. This work was supported in part by the Impact Fund of Children’s of Alabama.

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

    Institute of Scientific and Technical Information of China (English)

    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

    2011-01-01

    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.

  11. EFFECTS OF EXERCISE AND ISOPROTERENOL ON HEMODYNAMICS AND MYOCARDIAL VO2 IN LAMBS WITH AORTOPULMONARY SHUNTS

    NARCIS (Netherlands)

    GRATAMA, JWC; MEUZELAAR, JJ; DALINGHAUS, M; KOERS, JH; GERDING, AM; ZIJLSTRA, WG; KUIPERS, JRG

    1994-01-01

    To compare hemodynamic changes induced by isoproterenol and exercise stress tests in individuals with and without left, ventricular volume load, we studied 10 lambs with an aortopulmonary shunt [58 +/- 4% (SE) of left ventricular output] 2 wk after the shunt was created. Two studies, isoproterenol i

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

    Science.gov (United States)

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    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. PMID:21568400

  13. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Science.gov (United States)

    2010-04-01

    ... 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......

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

    Energy Technology Data Exchange (ETDEWEB)

    Konstas, Angelos A., E-mail: akonstas@partners.org [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)

    2011-11-15

    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.

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

    Directory of Open Access Journals (Sweden)

    Rahul T Chakor

    2012-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

    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.

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

    LENUS (Irish Health Repository)

    Stevens, Niall T

    2012-12-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Manuel C See IV

    2016-04-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Jose Roberto Tude Melo

    2015-09-01

    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.

  20. Band gap control of phononic beam with negative capacitance piezoelectric shunt

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

    Periodic arrays of negative capacitance shunted piezoelectric patches are employed to control the band gaps of phononic beams. The location and the extent of induced band gap depend on the mismatch in impedance generated by each patch. The total impedance mismatch is determined by the added mass and stiffness of each patch as well as the shunting electrical impedance. Therefore, the band gap of the shunted phononic beam can be actively tuned by appropriately selecting the value of negative capacitance. The control of the band gap of phononic beam with negative capacitive shunt is demonstrated numerically by employing transfer matrix method. The result reveals that using negative capacitive shunt to tune the band gap is effective.

  1. Indigenous cost-effective peritoneo-venous shunt for refractory ascites.

    Science.gov (United States)

    Marimuthu, K; Kumar, A Suresh; Sabanathan, S; Gowrishankar, A; Kumar, P Sasi; Rajkumar, J S

    2004-01-01

    About 5% of patients with chronic liver disease develop massive refractory ascites. These patients cease to respond to diuretic therapy and may develop prerenal azotemia. There is a small but definite role for the peritoneo-venous shunt in these patients. In our study of 36 patients, managed with locally made, single-valved peritoneo-venous shunts (GSAIMS shunts), shunt failure and complication rates were assessed postoperatively. There is a definite improvement in quality of life with this cost-effective locally made shunt if patients are selected carefully. Long-term follow-up of these patients is not possible because most of these patients succumb to advanced liver disease. PMID:15285240

  2. Cabinet Sh2104 with protective equipment for shunting reactors

    Energy Technology Data Exchange (ETDEWEB)

    Mogilev, G.P.; Kozina, N.I.; Ivanova, N.M.; Berger, P.A.

    1985-08-01

    A cabinet with a set of protective equipment for shunting reactors has been developed by the All-Union Scientific Research Institute of Relay Engineering. This Sh2104 cabinet houses relays for protection and control of compensating reactors as well. The equipment will protect a reactor whether the latter is connected into the line directly or through a tripping switch, by disconnecting it from the line or by actuating that switch respectively. For better reliability, the equipment for protection of shunting relays is grouped into a main set and a backup set. The main set includes longitudinally-acting differential phase-current relays, lead high-voltage insulation checkers, gas-leak protection, and standby reactor or line disconnectors. The backup set includes a 2-step zero-sequence current relay. The equipment for protection of compensating reactors consists of longitudinally acting differential current relays, distance relays, peak-current relays, and gas-leak protection. Two power supplies (50 W and 100 W) are provided for energizing all the equipment in this cabinet. Provided are also means for continuous operational monitoring and spot-check testing. The overall dimensions are 600x600x2200 mm/sup 3/, the total weight is 250 kg.

  3. Fabrication and characterization of shunted μ-SQUID

    Science.gov (United States)

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

    2014-04-01

    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.

  4. Fabrication and characterization of shunted μ-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Nikhil, E-mail: knikhil@iitk.ac.in [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)

    2014-04-24

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  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

    Institute of Scientific and Technical Information of China (English)

    江峰; 赵阳; 孙莲萍; 金惠明; 马杰

    2011-01-01

    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. Feasibility of conductance catheter-derived pressure–volume loops to investigate ventricular mechanics in shunted single ventricles

    OpenAIRE

    Butts, Ryan J.; Hsia, Tain-Yen; Baker, G. Hamilton

    2013-01-01

    We present pressure–volume loops obtained from two patients with single-ventricle physiology, one with a modified Blalock–Taussig shunt and one with a right ventricle-to-pulmonary artery shunt. The dissimilarities in pressure–volume loop contour and related indices highlight potentially important differences in ventricular mechanics between the shunt types.

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

    Science.gov (United States)

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

    2016-05-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    LAN Mei-juan; HE Xiao-di

    2009-01-01

    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.

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

    Science.gov (United States)

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

    1999-01-01

    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

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

    Directory of Open Access Journals (Sweden)

    Ahmet Mutlu

    2013-06-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Youssef Emam Youssef

    2010-04-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Arielle Spitze

    2014-01-01

    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.

  14. Characteristic lesion pattern and echocardiographic findings in extra-cardiac shunt-related stroke.

    Science.gov (United States)

    Mun, Jun Kyu; Park, Sung Ji; Kim, Suk Jae; Bang, Oh Young; Chung, Chin-Sang; Lee, Kwang Ho; Kim, Gyeong-Moon

    2016-10-15

    Among embolic strokes of undetermined source, under-recognized etiology such as extra-cardiac shunt could be a potential risk factor. We sought to characterize infarction patterns on diffusion-weighted imaging (DWI) and transesophageal echocardiography (TEE) findings in extra-cardiac shunt-related stroke. We enrolled 96 consecutive patients with cryptogenic stroke who had an extra- or intra-cardiac shunt. Diagnosis of the shunt was performed using TEE with agitated saline contrast and pulmonary vein isolation. Infarction patterns on DWI and total lesion volume were analyzed. Bubble amounts through the shunt were classified via the International Consensus Criteria (ICC). Short-term prognosis, patterns and size of DWI lesions, and involved vascular territories were not significantly different between two groups. Multivariate analysis revealed that extra-cardiac shunt group has a smaller total infarct volume (odds ratio [OR]=0.427, 95% confidence interval [95% CI] 0.228-0.799, p=0.008), and significantly higher bubble grade during resting state and lower grade during the Valsalva maneuver (OR= 0.539, 95% CI 0.438-0.663, psaline contrast. Further study is needed to confirm whether the extra-cardiac shunt is an independent risk factor. PMID:27653885

  15. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS).

    Science.gov (United States)

    Menzel, J; Schober, O; Reimer, P; Domschke, W

    1997-06-01

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; Pscintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. PMID:9169570

  16. Developmental intrahepatic shunts of childhood: radiological features and management

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the role of radiological techniques in the diagnosis and management of developmental intrahepatic shunts. Hepatic vascular fistulae are recognised sequelae of liver trauma and intrahepatic tumours. However, there are rare developmental malformations which may present in childhood or later life and which may carry life-threatening complications. Retrospective analysis of clinical and radiological data was carried out in 24 patients. Anomalies evaluated were: (a) direct communication between hepatic artery and hepatic veins; (b) congenital hepatoportal arteriovenous malformations; and (c) congenital portocaval anastomosis with persistent flow through the ductus venosus. Although rare, the prompt recognition of these vascular anomalies allows early surgical or radiological intervention and reversal of the haemodynamic complications. (orig.)

  17. Arterio-venous shunts or low oxygen utilization?

    Science.gov (United States)

    Rozin, Alexander P

    2010-02-01

    An idea of arteriovenous shunts (AVS) was proposed for explanation of dynamic regulation of oxygenation and venous hyperoxia. A formula enabling calculation of AVS and real CO2 production has recently been derived by comparing data of arterial and venous blood gases. Regarding venous hyperoxia, there is a need to differentiate capillary to tissue transport defect (low oxygen utilisation-LOU) from AVS, which may exist simultaneously. The AVS may be associated with normal or relatively high oxygen utilization from the capillary vessels and increased CO2 production. AVS is proposed to carry protective and 'stealing' properties including renal, cardiac, and pulmonary hemodynamic. Calculations of the AVS may be important for dynamic assessment of vascular and metabolic status and in emergency medicine. PMID:20026514

  18. Selective Harmonic Current Mitigation with Shunt Active Power Filter

    DEFF Research Database (Denmark)

    Hansen, Steffan; Lascu, Cristian; Asiminoaei, Lucian;

    2007-01-01

    drawbacks, the paper shows that the last two methods have a more compact mathematical representation which may extend to straightforward DSP implementation. However, the first method, i.e. selective compensation in harmonic dq-frame, is more flexible and allows a better tuning and adjustment, which is of a......The paper presents three methods of selective harmonic compensation with shunt Active Power Filters in different reference frames: harmonic dq-frame, stationary frame and fundamental dq-frame; and shows that the last two methods are derived from the first one. By analyzing their advantages and...... great importance in practice. For experimental tests only the selective harmonic control in fundamental dq-frame is presented, to demonstrate the selectiveness harmonic current compensation. The experimental results are performed in laboratory conditions on a 7 kVA Active Filter prototype, indicating a...

  19. The assessment of the patency of peritoneo-venous shunt with Tc99m-DTPA

    International Nuclear Information System (INIS)

    The patency of a LeVeen peritoneo-venous shunt was assessed with a radiopharmaceutical Tcsup(99m)-DTPA, Tcsup(99m)-sulphur colloid was used previously for this purpose Tcsup(99m)-DTPA was given intraperitoneally in three patients with ascites and the blood activity was determined. The radioactivity in the blood was found to be minimal and this was attributed to free pertechnetate. The kidneys and the bladder could not be demonstrated at 45 minutes. This also shows that the minimal activity in the blood was negligible for scintigraphic studies. The valve or the peritoneal tubing of the LeVeen shunt are sometimes occluded with a trombus or clot. So if the proximal part of the tube is demonstrated scintigraphically, it shows that the valve is functioning. But if the distal end of the tubing is occluded, this study will give a false-negative result. It can be claimed that if Tcsup(99m)-sulphur colloid is found in the blood, the shunt will be accepted as patent. The demonstration of the liver in 60 minutes after intraperitoneal injection shows the patency of the shunt precisely. But, demonstration of liver later than 60 min is not an evidence for a patent shunt. As seen with the shunt, after the intraperitoneal injection of Tcsup(99m)-DTPA, the tubing was demonstrated in 5 minutes and the kidneys and bladder in 15 minutes. This finding rules out any distal occlusion of the tubing of the shunt. Another indirect finding to assess the patency of the shunt is the increased background activity after 30 minutes in the chest. The advantages of using Tcsup(99m)-DTPA over Tcsup(99m) sulphur colloid are homogeneous distribution of the radiopharmaceutical in the ascitic fluid more rapid assessment of the patency of the shunt and lower radiation dose to the patient

  20. Gadolinium-enhanced magnetic resonance angiography of right ventricle to pulmonary artery shunts following Norwood 1 palliation in infants

    International Nuclear Information System (INIS)

    The classic Norwood I palliation for the treatment of hypoplastic left-heart disease includes an atrial septectomy, neoaorta creation, and a systemic-to-pulmonary artery shunt. The Norwood I palliation has been modified by the use of a right ventricle-to-pulmonary artery shunt instead of a traditional systemic-to-pulmonary artery shunt. Right ventricle-to-pulmonary artery shunts were non-invasively imaged in four infants using gadolinium-enhanced magnetic resonance angiography. Diagnostic MR angiograms were performed in all infants throughout the length of the shunt and were useful in the detection of shunt patency, stenosis, and aneurysm. Associated surgical conduits and shunts were also evaluated. All findings were verified by subsequent conventional angiography or surgery. (orig.)

  1. Design and Simulation of Microelectromechanical System Capacitive Shunt Switches

    Directory of Open Access Journals (Sweden)

    Haslina Jaafar

    2009-01-01

    Full Text Available Problem statement: RF MEMS switch is one of MEMS area that creates devices that have great potential to improve the performance of communication circuits and systems and enables the realization of micro size mechanical switches embedded in electronics devices. The low voltage switches are necessary due to their compatibility of standard IC technology in RF application and microelectronics systems. In realizing MEMS switches with low actuation voltage, spring constant of beam must be reduced. Design and simulation of capacitive RF MEMS shunt switches with regards to the pull in voltage were presented. Approach: Design and simulation had been done by using commercial simulation package, CoventorWare 2006. Several switches were designed with different meander spring beams to obtain lower voltage actuations using Architect Module in CoventorWare 2006. Results: Results verified with Finite Element Method (FEM and simple mathematical modeling. Each design gave different voltage actuations. The lowest actuation voltage simulated was 1.9 V. Average difference of simulated and calculated values was about 16%. This is because no fringing field was included in calculation. Finite Element Method (FEM analysis was done for switch C. Results showed that lower voltage can be obtained by using serpentine spring which lowers the spring constant and pull-in voltage as well. The lower pull-in time was primarily due to its very small dimensions and mass Conclusion: Low-voltage capacitive shunt RF MEMS switches were designed and simulated. These switches had actuation voltages of 1.9-7.0 V depending on the serpentine design. The other performance particularly switch C had a pull-in time of 15 µ sec after a voltage of 0-20 V was applied and the resonant frequency is 3153.1 Hz.

  2. Role of Glyoxylate Shunt in Oxidative Stress Response.

    Science.gov (United States)

    Ahn, Sungeun; Jung, Jaejoon; Jang, In-Ae; Madsen, Eugene L; Park, Woojun

    2016-05-27

    The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N2O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress. PMID:27036942

  3. Bacterial contamination of surgeons' gloves during shunt insertion; a pilot study

    DEFF Research Database (Denmark)

    Sørensen, Preben; Ejlertsen, Tove; Aaen, Dorte;

    2008-01-01

    Bacterial infection is a major cause of shunt dysfunction. It is well-known that the majority of pathogenic micro-organisms are low-virulent bacteria normally found on intact skin. Probably shunts become contaminated during surgery either by contact to the patient skin, or contact from contaminated...... handling the shunt and completing the operation. The plates were cultured for 6 days in both aerobic and anaerobic environment. In all cases the surgeons gloves were contaminated, and in six cases also the nurses' gloves were contaminated, as well as all three assistants. Propionebacterium acnes were...

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

    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.

  7. Mutual locking, chaos and devils staircase in two Josephson tunnel junctions with a common resistive shunt

    International Nuclear Information System (INIS)

    The authors have studied the phase-locking in a pair of individually biased, resistively and capacitively shunted Josephson junctions, coupled by a common resistive or capacitive shunt, on an analog computer. Under certain conditions locking is found to occur at all rational frequency ratios. A critical line is found in parameter space along which the steps form a complete devils staircase having a fractal dimension of 0.87. Beyond the critical line bifurcations occur on all steps following the Feigenbaum sequence to chaos. The Feigenbaum constants are recovered to a fair accuracy. Preliminary experiments with two Josephson tunnel junctions shunted on the chip by a gold-indium film are discussed

  8. 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

    Institute of Scientific and Technical Information of China (English)

    金浩; 张卫; 朱扬清; 邹煜; 周秋锋; 刘星; 钱伟; 左常阳

    2015-01-01

    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 .

  9. Heparin-induced thrombocytopenia associated with acute liver graft failure

    OpenAIRE

    Pannicke, Nadine; Pollok, Joerg-Matthias; Kluge, Stefan; Petzoldt, Martin

    2012-01-01

    An orthotopic liver transplantation (OLT) is of a proven benefit in an acute liver failure (ALF). Heparin-induced thrombocytopenia (HIT) is strongly associated with thromboembolic complications. We present the case of a 56-year-old patient who underwent an OLT owing to an ALF of unknown aetiology. HIT type II with consecutive hepatic and portal vein thrombosis caused progressive graft failure. Total hepatectomy and porto-caval shunt were performed to reduce the toxic effects of liver cell nec...

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

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiang; He Lidong; Huo Genglei; Che Jianye

    2008-01-01

    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.

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

    Indian Academy of Sciences (India)

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

    2015-06-01

    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.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    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......This research is focused on one of the problems frequently encountered in spot welding in industry. In many applications several spot welds are made close to each other. The spots made after the first spot may become smaller in size due to shunt effect. A numerical and experimental study has been....... 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....

  13. Anal extrusion of migrated ventriculo-peritoneal shunt catheter: An unusual complication and review of literature

    Science.gov (United States)

    Sarkari, Avijit; Borkar, Sachin A.; Mahapatra, A. K.

    2016-01-01

    Authors present an unusual case of anal extrusion of peritoneal end of ventriculo-peritoneal shunt in a 2-year-old male child. Pertinent literature is reviewed regarding this rare complication of a very commonly performed neurosurgical procedure.

  14. Superior vena cava syndrome after pulsatile bidirectional Glenn shunt procedure: Perioperative implications

    Directory of Open Access Journals (Sweden)

    Neema Praveen

    2009-01-01

    Full Text Available Bidirectional superior cavopulmonary shunt (bidirectional Glenn shunt is generally performed in many congenital cardiac anomalies where complete two ventricle circulations cannot be easily achieved. The advantages of BDG shunt are achieved by partially separating the pulmonary and systemic venous circuits, and include reduced ventricular preload and long-term preservation of myocardium. The benefits of additional pulsatile pulmonary blood flow include the potential growth of pulmonary arteries, possible improvement in arterial oxygen saturation, and possible prevention of development of pulmonary arteriovenous malformations. However, increase in the systemic venous pressure after BDG with additional pulsatile blood flow is known. We describe the peri-operative implications of severe flow reversal in the superior vena cava after pulsatile BDG shunt construction in a child who presented for surgical interruption of the main pulmonary artery.

  15. The transjugular portosystemic stent shunt (TIPSS) as an intervention in clinical complication of portal hypertension

    International Nuclear Information System (INIS)

    Most frequent complications in patients with liver cirrhosis are due to portal hypertension. Beside ascites circumvent vessles formate with vasodilatation. Due to counterregulation a secondary hyperaldosteronism develops with release of vasocontrictive agents. If conservative and endoscopic methods fail, indication for building a portosystemic shunt is given. The TIPSS procedure is less invasive than the surgical method of Warren-Shunt, so the radiological intervention has replaced surgery. Reducing the portal pressure by the shunt, the clinical complications change for the better. Still problems are defined as hepatic encephalopathy and right ventricular heart failure. Regular follow up investigations have to be performed to detect complications in the shunt. Using regular clinical and radiological check up TIPSS is of clinical benefit with good long term results. (orig.)

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

    Science.gov (United States)

    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

    2015-06-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

    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.

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

    Science.gov (United States)

    Wang, Jiaxi; Lin, Boliang; Jin, Junchen

    2016-01-01

    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

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

    Science.gov (United States)

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

    2016-01-01

    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.

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

    Science.gov (United States)

    Jin, Junchen

    2016-01-01

    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

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2014-10-15

    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.)

  3. What are the implications of the spontaneous spleno-renal shunts in liver cirrhosis?

    OpenAIRE

    Cirillo Michele; Capone Domenico; Tarantino Marianna; Riccio Antonio; Conca Paolo; Citro Vincenzo; Tarantino Giovanni; Lobello Roberto; Iaccarino Vittorio

    2009-01-01

    Abstract Background Although significant advances are expected to be made in the assessment of the portal hypertension-related complications, the prognostic role of spleno-renal shunts has not been fully explored so far. Clarifying this aspect could help tackle the life-treating events occurring in patients suffering from liver cirrhosis. The aim of the study was to analyze the relationships between the spleno-renal shunts presence at doppler ultrasound and the liver cirrhosis complications. ...

  4. Goel′s Teflon sponge internal shunt for anterior spinal arachnoid cyst

    OpenAIRE

    Raghvendra Ramdasi; Abhidha Shah

    2014-01-01

    We report a case of a 6-year-old boy who presented with progressive quadriparesis and bowel-bladder incontinence. Magnetic resonance imaging (MRI) of the spine showed anteriorly located arachnoid cyst in the cervicodorsal region. Following marsupialization of the cyst, an internal Teflon sponge shunt (Goel's shunt) was done that extended from the cyst cavity to the subarchnoid space. The patient improved dramatically in his symptoms. The physical nature of the teflon sponge and its usefulness...

  5. Congenital hepatoportal arteriovenous fistula associated with intrahepatic portal vein aneurysm and portohepatic venous shunt: case report

    International Nuclear Information System (INIS)

    A congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm is a rare type of arteriovenous malformation. Only 14 pediatric cases have been reported to the best of the authors' knowledge. An intrahepatic shunt between the portal and systemic veins is also relatively rare. We report a case of a congenital hepatoportal arteriovenous fistula associated with an intrahepatic portal vein aneurysm and a portohepatic venous shunt in a neonate who presented with tachypnea and melena

  6. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt

    OpenAIRE

    Pickard John D; Richards Hugh K; Czosnyka Marek; Allin David M; Czosnyka Zofia H

    2008-01-01

    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 perf...

  7. Alterations in the aqueous humor proteome in patients with a glaucoma shunt device

    OpenAIRE

    Anshu, Arundhati; Price, Marianne O; Richardson, Matthew R; Segu, Zaneer M.; Lai, Xianyin; Yoder, Mervin C.; Price, Francis W.

    2011-01-01

    Purpose To investigate whether implantation of a glaucoma shunt device leads to inappropriate accumulation of plasma derived proteins in the aqueous humor. Methods Aqueous humor samples were collected from 11 patients (study group) with a glaucoma shunt device undergoing either cataract surgery or a corneal transplant and 11 patients (control) with senile cataract undergoing routine cataract extraction. Of the study group, 9 had an Ahmed valve implant and 2 eyes had a Baerveldt implant. Trypt...

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

    Directory of Open Access Journals (Sweden)

    Andi Anita Utami

    2013-04-01

    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

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

    Directory of Open Access Journals (Sweden)

    Mitra S

    2001-04-01

    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.

  10. Radionuclide assessment of LeVeen shunt patency. [/sup 99m/Tc tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Kirchmer, N.; Hart, U.

    1977-02-01

    Patients with an initially satisfactory result following placement of a LeVeen peritoneo-venous shunt for intractable ascites may reaccumulate massive ascites. Determination of the etiology of such is a difficult problem. We describe a simple method using intraperitoneal injection of Technetium-99m sulfur colloid and three gamma camera scintiphotos of the chest and abdomen to allow prompt determination of shunt occlusion as the cause.

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

    Science.gov (United States)

    Tekletsadik, Kasegn D.

    2007-10-16

    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.

  12. Scintigraphic evaluation of hepatic blood flow after intrahepatic portosystemic shunt (TIPS)

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, J. [Department of Medicine B, University of Muenster, Muenster (Germany); Schober, O. [Department of Nuclear Medicine, University of Muenster, Muenster (Germany); Reimer, P. [Department of Radiology, University of Muenster, Muenster (Germany); Domschke, W. [Department of Medicine B, University of Muenster, Muenster (Germany)

    1997-06-10

    In patients with liver cirrhosis a transjugularly placed intrahepatic portocaval shunt (TIPS) is a non-surgical portosystemic device which aims to reduce portal venous pressure. In comparison with Doppler sonography, we evaluated in 28 patients the diagnostic impact of liver perfusion scintigraphy (with technetium-99m diethylene triamine penta-acetic acid) in the assessment of changes in the hepatic blood flow after TIPS shunting. The arterial and portal contributions to hepatic flow were calculated from the areas under the biphasic time-activity curve. In the course of TIPS shunting, patency is threatened by reocclusion. Angiography is the gold standard for TIPS shunt reassessment. However, there is a need for a less invasive diagnostic procedure, such as scintigraphy or Doppler sonography, for the early detection of shunt insufficiency. Scintigraphy demonstrated that prior to TIPS shunting the portal venous contribution to hepatic perfusion was reduced to 29.2%, this reduction being due to portal hypertension. After TIPS placement a significant increase in portal venous perfusion was observed (38.2%; P<0.02). TIPS shunt occlusion was identified in patients by a significant reduction in the scintigraphically measured portal venous contribution to hepatic blood flow. Hepatic perfusion scintigraphy appears to be a valuable method to determine the immediate effect of TIPS on hepatic blood flow. Post-TIPS follow-up studies of hepatic haemodynamics by liver perfusion scintigraphy appear able to contribute to the detection of TIPS shunt occlusion before the clinical consequences of this complication have become apparent. (orig.). With 4 figs., 3 tabs.

  13. RECURRENT HEPATIC ENCEPHALOPATHY IN A CIRRHOTIC PATIENT WITH LARGE GASTRORENAL SHUNT: ONE CASE REPORT

    Institute of Scientific and Technical Information of China (English)

    汪余勤; 汪保灿; 顾胜利; 范建高

    2011-01-01

    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...

  14. Acute Bronchitis

    Science.gov (United States)

    ... of bronchitis: acute and chronic. Most cases of acute bronchitis get better within several days. But your cough ... that cause colds and the flu often cause acute bronchitis. These viruses spread through the air when people ...

  15. Unusual shunt for symptomatic portal vein thrombosis after liver transplantation - Clatworthy revisited.

    Science.gov (United States)

    Mali, V P; Robless, P A; Aw, M; Loh, D L; Quak, S H; Prabhakaran, K

    2012-06-01

    PV thrombosis is not an uncommon occurrence following pediatric LT. Symptomatic PHT following PV thrombosis is treated medically, surgical portosystemic shunting (mesorex, splenorenal, and mesocaval) being reserved for refractory cases. A 10-yr-old boy suffered recurrent malena and hemorrhagic shock because of chronic PV thrombosis following LT nine yr ago (1999). Extensive work-up failed to localize the bleeding source. The liver function remained normal. Initial attempts at surgical shunts failed owing to thrombosis (mesocaval 2001, splenorenal, inferior mesenteric-left renal vein, splenic-left external iliac vein 2008). In this situation, we performed a Clatworthy shunt by anastomosing the divided lower end of the LCIV to the side of SMV. There was a single, large caliber anastomosis. Post-operatively, the malena stopped completely, and clinically, there was no lower limb edema or encephalopathy. Doppler USG revealed persistence of hepatopetal flow within the portal collaterals. Follow-up at two yr reveals stable hepatic function with a patent shunt. To the best of our knowledge, we are not aware of a Clatworthy shunt being performed in a transplant setting. We reviewed the literature pertaining to this shunt in non-transplant patients with PHT.

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

    Directory of Open Access Journals (Sweden)

    Natarajan Muthukumar

    2012-01-01

    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.

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

    Science.gov (United States)

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

    2014-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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

    2006-01-01

    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.

  19. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    Science.gov (United States)

    Chen, Yu-Wei; Wu, Yu-Te; Lin, Jhin-Shyaun; Yang, Wu-Chang; Hsu, Yung-Ho; Lee, Kuo-Hua; Ou, Shou-Ming; Chen, Yung-Tai; Shih, Chia-Jen; Lee, Pui-Ching; Chan, Chia-Hao; Chung, Ming-Yi; Lin, Chih-Ching

    2016-01-01

    Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001), lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025), right-sided (31.8% vs. 18.4%, p = 0.002) and upper arm AVF (26.6% vs. 9.7%, p < 0.001), and higher mean dynamic venous pressure (DVP) (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021). In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs), rs275653 (Odds ratio 1.90, p = 0.038) and rs1492099 (Odds ratio 2.29, p = 0.017) of angiotensin II receptor 1 (AGTR1), were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA) of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005). In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could be a

  20. Association of Genetic Polymorphisms of Renin–Angiotensin–Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

    Directory of Open Access Journals (Sweden)

    Yu-Wei Chen

    2016-05-01

    Full Text Available Hemodialysis (HD is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001, lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025, right-sided (31.8% vs. 18.4%, p = 0.002 and upper arm AVF (26.6% vs. 9.7%, p < 0.001, and higher mean dynamic venous pressure (DVP (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021. In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs, rs275653 (Odds ratio 1.90, p = 0.038 and rs1492099 (Odds ratio 2.29, p = 0.017 of angiotensin II receptor 1 (AGTR1, were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005. In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could

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

    Directory of Open Access Journals (Sweden)

    Ana Maldonado-Junyent

    2015-04-01

    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.

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

    Science.gov (United States)

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

    2015-01-01

    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.

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

    Science.gov (United States)

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

    2011-09-01

    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.

  4. Radiation doses to children with shunt-treated hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2007-12-15

    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.)

  5. Battery Equalization Control Based on the Shunt Transistor Method

    Directory of Open Access Journals (Sweden)

    Gallardo-Lozano Javier

    2014-12-01

    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.

  6. Peritoneovenous shunt in treatment of ascites in patients with cirrhosis. A preliminary report with special reference to pathophysiology

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Malchow-Møller, A; Ring-Larsen, H;

    1983-01-01

    Peritoneovenous shunts (LeVeen type) were implanted in seven patients with cirrhosis complicated by ascites refractory to diuretic treatment. Three patients died of gastrointestinal bleeding and hepatic coma 1 to 7 weeks after the shunt implantation. The patients who died were those with the most...... severely impaired liver and kidney function. In two of the four surviving patients (observation time, 5-24 months) the shunt was patent during the observation time, and ascites disappeared. In the other two the shunt closed, in one patient repeatedly following several re-implantations. Enhanced urinary...... sodium excretion was observed in patients with patent shunts. After disappearance of ascites, the splanchnic venous pressures became less deranged. Long-term change in plasma volume or circulating albumin mass could not be detected. A patent shunt increases the drainage from the peritoneal cavity...

  7. Effects of isradipine and other calcium antagonists on arteriovenous-shunt flow in anesthetized rabbits and cats

    Energy Technology Data Exchange (ETDEWEB)

    Hof, R.P.

    1989-04-17

    The effects of vasodilators on arteriovenous (AV)-shunt flow was investigated in anesthetized cats and rabbits, using the tracer microsphere method. In cats, the calcium antagonist isradipine reduced AV-shunt flow; verapamil showed a similar tendency and nicardipine was without effect. Dihydralazine strongly increased, but nitroglycerin and dipyridamole decreased AV-shunt flow. In rabbits, the effects of isradipine and verapamil were similar to those seen in cats. Sodium nitroprusside had no effect, whereas prazosin, minoxidil, and the potassium-channel activator cromakalim increased AV-shunt flow. The contrasting effects of drugs sharing the same mechanism of action suggest that target-tissue selectivity is more important than the mechanism of action. An increase of AV-shunt flow is unlikely to be beneficial but could be associated with a number of undesirable side effects. It might negatively affect migraine sufferers and, if AV-shunt dilatation shows no tolerance development, it represents an unnecessary hemodynamic burden for the heart.

  8. Universal statistics of parasitic shunt formation in solar cells, and its implications for cell to module efficiency gap

    OpenAIRE

    Dongaonkar, Sourabh; Alam, Muhammad A.

    2013-01-01

    Parasitic shunt formation is an important cause of variability and module efficiency loss in all photovoltaic technologies. In this letter, we quantify the nature of this shunt variability in fourmajor thin film photovoltaic (TFPV) technologies, namely, amorphous silicon (a-Si:H), organic (OPV), Cu(In,Ga)SSe (CIGS), and CdTe. We analyze a wide variety of datasets to show that the shunt current exhibits a robust universal log-normal behavior for all these technologies. We affirm this conclusio...

  9. Ventriculo-bipleural shunt as last resort in a 4-year-old child in whom a VP and VA shunt failed.

    Science.gov (United States)

    Ratliff, Miriam; Unterberg, Andreas; Bächli, Heidi

    2016-03-01

    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.

  10. Adaptive right ventricular performance in response to acutely increased afterload in a lamb model of congenital heart disease: evidence for enhanced Anrep effect.

    Science.gov (United States)

    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

    2014-04-15

    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.

  11. Implementation of an artificial neuronal network to predict shunt necessity in carotid surgery.

    Science.gov (United States)

    Aleksic, Marko; Luebke, Thomas; Heckenkamp, Joerg; Gawenda, Michael; Reichert, Viktor; Brunkwall, Jan

    2008-09-01

    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.

  12. In vitro hydrodynamic properties of the Miethke proGAV hydrocephalus shunt

    Directory of Open Access Journals (Sweden)

    Richards Hugh K

    2006-06-01

    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.

  13. Spontaneous resolution of splenic infarcts after distal splenorenal shunt in children with extra hepatic portal venous obstruction: Our experience

    Directory of Open Access Journals (Sweden)

    Arbinder Kumar

    2014-01-01

    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.

  14. The clinical application and nursing experience of adjustable shunt valve in treatment for patients with normal pressure hydrocephalus

    Directory of Open Access Journals (Sweden)

    YANG Li-rong

    2012-02-01

    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.

  15. Reduction of astrogliosis and microgliosis by cerebrospinal fluid shunting in experimental hydrocephalus

    Directory of Open Access Journals (Sweden)

    Miller Janet M

    2007-06-01

    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

  16. What are the implications of the spontaneous spleno-renal shunts in liver cirrhosis?

    Directory of Open Access Journals (Sweden)

    Cirillo Michele

    2009-11-01

    Full Text Available Abstract Background Although significant advances are expected to be made in the assessment of the portal hypertension-related complications, the prognostic role of spleno-renal shunts has not been fully explored so far. Clarifying this aspect could help tackle the life-treating events occurring in patients suffering from liver cirrhosis. The aim of the study was to analyze the relationships between the spleno-renal shunts presence at doppler ultrasound and the liver cirrhosis complications. Methods Design: eighty one patients out of 129 formed the study population (35 females. Chronic liver damage in these patients was caused by HCV (66, HBV (2, alcohol abuse (2 or unknown etiology, likely non-alcoholic steatohepatitis (11. Setting: two Liver Units of university/primary hospitals in Southern Italy. Main outcome measures: grading of esofageal varices; detection of ascites: assessment of hepatic encephalopathy; evaluation of liver cirrhosis severity; tracking hepatocellular carcinoma; doppler features of spleno-renal shunts and splenic flow velocity; spleen longitudinal diameter at sonography. Results The prevalence of spleno-renal shunts was 18.5%, without no difference concerning the etiology (HCV versus non-HCV, p = 0.870; the prevalence of hepatocellular carcinoma in patients with spleno-renal shunts was superior to that of patients without them (Pearson Chi-square, p = 0.006, power of sample size 74%, also after adjustment for liver decompensation (p = 0.024. The median score of hepatic encephalopathy in patients with and without spleno-renal shunts was similar, i.e., 0 (range, 0-2 versus 0 (0 - 3, p = 0.67. The median splenic vein flow velocity in patients with spleno-renal shunts was significantly inferior to that of patients without them, i.e., 13 cm/sec (95% confidence intervals, 6-18 versus 21 cm/sec (17-24, p Conclusion Taking into consideration the relatively small sample size, patients with spleno-renal shunts are burdened by an

  17. Cerebral oxygenation and processed EEG response to clamping and shunting during carotid endarterectomy under general anesthesia.

    Science.gov (United States)

    Perez, William; Dukatz, Christopher; El-Dalati, Sami; Duncan, James; Abdel-Rasoul, Mahmoud; Springer, Andrew; Go, Michael R; Dzwonczyk, Roger

    2015-12-01

    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

  18. Impact of cerebrospinal fluid shunting for idiopathic normal pressure hydrocephalus on the amyloid cascade.

    Directory of Open Access Journals (Sweden)

    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.

  19. External lumbar drain: A pragmatic test for prediction of shunt outcomes in idiopathic normal pressure hydrocephalus

    Directory of Open Access Journals (Sweden)

    Silky Chotai

    2014-01-01

    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

  20. Decompensated porto-pulmonary hypertension in a cirrhotic patient with thrombosis of portocaval shunt

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    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.

  1. Micro-fabricated shunt to mimic arachnoid granulations for the treatment of communicating hydrocephalus.

    Science.gov (United States)

    Kralick, Francis; Oh, Jonghyun; Medina, Tim; Noh, Hongseok Moses

    2012-01-01

    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.

  2. Laboratory study on "intracranial hypotension" created by pumping the chamber of a hydrocephalus shunt

    Directory of Open Access Journals (Sweden)

    Richards Hugh K

    2007-03-01

    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.

  3. Unified power flow controller based on two shunt converters and a series capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Khoshkbar Sadigh, Arash; Tarafdar Hagh, Mehrdad; Sabahi, Mehran [Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz (Iran)

    2010-12-15

    In this paper a novel configuration of unified power flow controller (UPFC) which consists of two shunt converters and a series capacitor is proposed. In this configuration, a series capacitor is used between two shunt converters to inject desired series voltage. As a result, it is possible to control the active and reactive power flow as same as the conventional configuration of UPFC. The main advantage of the proposed UPFC in comparison with the conventional configuration is injection of a series voltage waveform with a very low total harmonic distortion (THD). Also, using two shunt converters instead of a series and a shunt converters, results in reduction of design efforts and simplification of control, measuring and protection strategies. An optimal control strategy based on the discrete model of converters is applied to shunt converters. The proposed UPFC is simulated using PSCAD/EMTDC and MATLAB software and simulation results are presented to validate the effectiveness of the novel configuration of UPFC. Also, the experimental results which are obtained from an experimental set-up are presented. (author)

  4. [Lymphangiomyomatosis with chylous ascites treatment successfully by peritoneo-venous shunting].

    Science.gov (United States)

    Kimura, M; Morikawa, T; Takeuchi, K; Furuie, H; Fukimura, M; Mikami, R; Kakuta, Y; Kawamura, S; Tashiro, Y

    1996-05-01

    A 49-year-old woman was admitted to our hospital because of coughing and dyspnea. A chest roentogenogram showed emphysematous changes and a diffuse reticular shadow. A high-resolution CT scan of the chest showed many small cysts throughout the lungs. Lymphangiomyomatosis was diagnosed after examination of a specimen obtained by transbronchial biopsy. Abdominal distention due to chylous ascites developed during the hospital stay despite anti-estrogen therapy. Because the ascites was resistant to conservative therapy, we decided to begin peritoneo-venous shunting with a Denver Shunt system. After the operation, the abdominal distention was controlled for 1 year and 11 months, at which time the patient died of respiratory and heart failure with pneumonia. At autopsy, the shunt was patent and functional although about 900 ml of serous ascites fluid was present. An adenocarcinoma was found in the upper lobe of the right lung, but it may not have been related to the lymphangiomyomatosis. Peritoneovenous shunting with a Denver Shunt can be used to treat chylous ascites due to lymphangiomyomatosis when conservative therapy is insufficient. PMID:8753114

  5. When do the symptoms of autonomic nervous system malfunction appear in patients with Parkinson’s disease?

    Directory of Open Access Journals (Sweden)

    De Luka Silvio R.

    2014-01-01

    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

  6. [Acute respiratory distress syndrome].

    Science.gov (United States)

    Estenssoro, Elisa; Dubin, Arnaldo

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is an acute respiratory failure produced by an inflammatory edema secondary to increased lung capillary permeability. This causes alveolar flooding and subsequently deep hypoxemia, with intrapulmonary shunt as its most important underlying mechanism. Characteristically, this alteration is unresponsive to high FIO2 and only reverses with end-expiratory positive pressure (PEEP). Pulmonary infiltrates on CXR and CT are the hallmark, together with decreased lung compliance. ARDS always occurs within a week of exposition to a precipitating factor; most frequently pneumonia, shock, aspiration of gastric contents, sepsis, and trauma. In CT scan, the disease is frequently inhomogeneous, with gravitational infiltrates coexisting with normal-density areas and also with hyperaerated parenchyma. Mortality is high (30-60%) especially in ARDS associated with septic shock and neurocritical diseases. The cornerstone of therapy lies in the treatment of the underlying cause and in the use mechanical ventilation which, if inappropriately administered, can lead to ventilator-induced lung injury. Tidal volume = 6 ml/kg of ideal body weight to maintain an end-inspiratory (plateau) pressure = 30 cm H2O ("protective ventilation") is the only variable consistently associated with decreased mortality. Moderate-to-high PEEP levels are frequently required to treat hypoxemia, yet no specific level or titration strategy has improved outcomes. Recently, the use of early prone positioning in patients with PaO2/FIO2 = 150 was associated with increased survival. In severely hypoxemic patients, it may be necessary to use adjuvants of mechanical ventilation as recruitment maneuvers, pressure-controlled modes, neuromuscular blocking agents, and extracorporeal-membrane oxygenation. Fluid restriction appears beneficial. PMID:27576283

  7. Acute Pancreatitis and Pregnancy

    Science.gov (United States)

    ... Acute Pancreatitis > Acute Pancreatitis and Pregnancy test Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is ... of acute pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for ...

  8. Effect of positive end-expiratory pressure on pulmonary shunt and dynamic compliance during abdominal surgery

    DEFF Research Database (Denmark)

    Spadaro, S.; Karbing, Dan Stieper; Mauri, T.;

    2016-01-01

    52 patients undergoing either laparotomy or laparoscopic surgery. Three levels of PEEP were applied in random order: (1) zero (ZEEP), (2) 5 cmH2O and (3) 10 cmH2O. Pulmonary shunt and ventilation/perfusion mismatch were assessed by the automatic lung parameter estimator system. RESULTS: Pulmonary......BACKGROUND: General anaesthesia decreases pulmonary compliance and increases pulmonary shunt due to the development of atelectasis. The presence of capnoperitoneum during laparoscopic surgery may further decrease functional residual capacity, promoting an increased amount of atelectasis compared...... of 10 cmH2O. Although laparoscopic surgery was associated with a lower pulmonary compliance, increasing levels of PEEP were able to ameliorate it in both groups. CONCLUSION: Both surgeries have similar negative effects on pulmonary shunt, while the presence of capnoperitoneum reduced only the...

  9. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt: A Case Report and Literature Review.

    Science.gov (United States)

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

    2015-11-01

    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).

  10. Wave propagation in beams with anti-symmetric piezoelectric shunting arrays

    Science.gov (United States)

    Sheng-Bing, Chen; Gang, Wang

    2016-03-01

    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).

  11. Accurate calibration of RL shunts for piezoelectric vibration damping of flexible structures

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Krenk, Steen

    2016-01-01

    the residualcontributions, represented by two correction factors, modify both the apparent transducer capacitanceand the shunt impedance. Explicit expressions for the correction of the shunt circuit inductance and resistanceare presented in a form that is generally applicable to calibration formulae derived on the basisof...... an assumed single-mode structure, in which the modal interaction has been deliberately neglected.A design procedure is devised and subsequently verified by numerical examples, demonstrating that effectivemitigation can be obtained for an arbitrary vibration mode when the residual mode correction isincluded......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...

  12. Role of Mitochondria-rich Cells for Passive Chloride Transport, discussion of Ussing's Contribution to Our Understanding of Shunt Pathways in Epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Kristensen, Poul; Nedergaard, Signe Nielsen;

    2001-01-01

    Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport......Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport...

  13. Deconvolution analysis in radionuclide quantitation at left-to-right cardiac shunts

    International Nuclear Information System (INIS)

    A poor bolus injection results in an unsatisfactory quantitative radionuclide angio-cardiogram in as many as 20% of chiledren with possible left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (> 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). (QP/QS was determined using the gamma function. The mean (QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation QP/QS > 1.2:1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p > 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p < 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted

  14. Deconvolution analysis in radionuclide quantitation of left-to-right cardiac shunts.

    Science.gov (United States)

    Alderson, P O; Douglass, K H; Mendenhall, K G; Guadiani, V A; Watson, D C; Links, J M; Wagner, H N

    1979-06-01

    A poor bolus injection results in an unsatisfactory quantitative radionuclide angiocardiogram in as many as 20% of children with possible, left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (greater than 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). QP/QS was determined using the gamma function. The mean QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation (QP/QS greater than 1.2 : 1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p greater than 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p less than 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted. PMID:536823

  15. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction.

    Science.gov (United States)

    Suresh, Supraja; Black, Richard A

    2015-02-01

    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

  16. Experimental study of an endothelial progenitor cell coated stent in transjugular intrahepatic portosystemic shunt

    International Nuclear Information System (INIS)

    Objective: To evaluate the efficacy of a self-expandable metal stent coated with autologous endothelial progenitor cells (EPCs) for prevention of restenosis in transjugular intrahepatic portosystemic shunt (TIPS) in a swine model. Methods: EPCs were coated on the metal stents using fibrin gel before TIPS procedure. TIPS was performed in 15 young adult pigs, using an autologous EPC-seeded stent (treatment group, n=9) or a conventional bare metal stent (control group, n=6). All pigs were sacrificed at 2 weeks after TIPS procedure. Portography was performed immediately before the euthanasia. Gross and microscopic pathological exams and immunohistochemical exams of the TIPS track specimens were performed. Fisher test and t test were used to analyse the data. Results: TIPS was performed successfully in all the 15 swine. On day 14 of follow-up, direct portography and necropsy demonstrated that 5 shunts remained patent, 2 shunts stenosed, and the remaining 2 shunts occluded in the treatment group (n=9); while 5 shunts were occluded and one shunt was stenotic in the control group (n=6). The patency rate was 56% vs 0 (P=0.03) between the two groups. Histological analyses showed a greater pseudo-intimal hyperplasia in the TIPS track of the control group than that of the treatment group (pseudointimal thickness at hepatic vein, hepatic parenchyma and portal vein site was (1.2±0.4), (1.3±0.5), (1.5±0.4) mm vs (1.0±0.6), (0.9±0.5), (1.0±0.4) mm respectively (P<0.05). Conclusion: The EPC-coated metal stent is feasibly constructed in vitro and improves the patency in TIPS in a porcine model. (authors)

  17. Evaluation of blood access dysfunction based on a wavelet transform analysis of shunt murmurs.

    Science.gov (United States)

    Sato, Toshio; Tsuji, Kiichi; Kawashima, Norimichi; Agishi, Tetsuzo; Toma, Hiroshi

    2006-01-01

    We investigated shunt murmurs based on wavelet transform analysis as a new method for assessing vascular access function. In the present study, in patients with venous stenosis near an arteriovenous fistula (A-V fistula), a sensor was placed at different positions around the stenosis and shunt murmur signals obtained using a measurement system were subjected to time-frequency analysis based on wavelet transforms. The shunt murmurs obtained from the stenotic region closely represented some features of murmurs that are often referred to as "high-pitch" murmurs in the clinical setting. In contrast, shunt murmurs obtained about 5 cm downstream of the stenotic region closely represented some features of murmurs that are often referred to as "low-pitch" murmurs in the clinical setting. Furthermore, with the aim of extending the lifespan of arteriovenous grafts (A-V grafts) by detecting and treating stenotic lesions before the A-V graft becomes occluded, we evaluated the possibility of utilizing the present shunt murmur analysis for monitoring stenosis in such A-V grafts. When shunt murmurs from patients with A-V grafts were analyzed, the results suggested that the blood flow through the venous anastomosis of the graft was the most turbulent. This present method whereby blood flow in an A-V fistula is assessed based on the frequency distribution on a time-frequency plane by wavelet transform analysis is advantageous because findings are not markedly affected by sensor attachment. Furthermore, because the sensor is attached using an adhesive collar, measurements can be taken over a short period of time before each dialysis session. PMID:16807812

  18. Evolving Insights into the Pathophysiology of Diabetic Neuropathy: Implications of Malfunctioning Glia and Discovery of Novel Therapeutic Targets.

    Science.gov (United States)

    Rahman, Md Habibur; Jha, Mithilesh Kumar; Suk, Kyoungho

    2016-01-01

    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.

  19. Semi-active control of piezoelectric coating's underwater sound absorption by combining design of the shunt impedances

    Science.gov (United States)

    Sun, Yang; Li, Zhaohui; Huang, Aigen; Li, Qihu

    2015-10-01

    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.

  20. A retrospective study of central nervous system shunt infections diagnosed in a university hospital during a 4-year period

    Directory of Open Access Journals (Sweden)

    Coskun Erdal

    2006-03-01

    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.

  1. Bronchitis - acute

    Science.gov (United States)

    ... sharing features on this page, please enable JavaScript. Acute bronchitis is swelling and inflammation in the main passages ... present only for a short time. Causes When acute bronchitis occurs, it almost always comes after having a ...

  2. Radiation Exposure in Transjugular Intrahepatic Portosystemic Shunt Creation

    Energy Technology Data Exchange (ETDEWEB)

    Miraglia, Roberto, E-mail: rmiraglia@ismett.edu; Maruzzelli, Luigi, E-mail: lmaruzzelli@ismett.edu; Cortis, Kelvin, E-mail: kelvincortis@ismett.edu [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy); D’Amico, Mario, E-mail: mdamico@ismett.edu [University of Palermo, Department of Radiology (Italy); Floridia, Gaetano, E-mail: gfloridia@ismett.edu; Gallo, Giuseppe, E-mail: ggallo@ismett.edu; Tafaro, Corrado, E-mail: ctafaro@ismett.edu; Luca, Angelo, E-mail: aluca@ismett.edu [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Radiology Service, Department of Diagnostic and Therapeutic Services (Italy)

    2016-02-15

    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.

  3. Centerline Longitudinal Shunt Slot Excitation by Elliptic shaped single Ridge Waveguide

    Directory of Open Access Journals (Sweden)

    Mehdi Moradian

    2011-07-01

    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.

  4. A new hysteresis band current control technique for a shunt active filter

    OpenAIRE

    KALE, MURAT; ÖZDEMİR, ENGİN

    2015-01-01

    This paper proposes a hysteresis band (HB) current control technique to reduce the power losses in a shunt active filter. During a switching period in the zero-crossing region, the inverter output current flows through a transistor. By changing the direction, it flows through the free-wheeling diode of the same switch in an inverter leg, or vice versa. The shunt active filter current typically has 6 zero-crossing regions during a fundamental frequency cycle. This paper presents a HB current c...

  5. Single-phase shunt active filter interfacing renewable energy sources with the power grid

    OpenAIRE

    Neves, Pedro; Gonçalves, Domingos; Pinto, J. G.; Alves, Renato; Afonso, João L.

    2009-01-01

    This paper presents a single-phase Shunt Active Filter combined with a Maximum Power Point Tracker (MPPT) connected to a solar panel array. The Shunt Active Filter’s power stage consists of a two-leg IGBT inverter commanded by a Digital Signal Processor (DSP) with control based on the Theory of Instantaneous Reactive Power (p-q Theory). The MPPT is based on a step-up circuit commanded by a DSP with MPPT Algorithm implemented. The output of the MPPT circuit is connected...

  6. Non-invasive assessment of shunt and ventilation/perfusion ratio in neonates with pulmonary failure

    OpenAIRE

    H. Smith; Jones, J.

    2001-01-01

    AIMS—To make non-invasive measurements of right to left (R-L) shunt and reduced ventilation/perfusion ratio (VA/Q) in neonates with pulmonary failure and to examine sequential changes in these variables after treatment.
METHODS—Twelve neonates with pulmonary failure were studied. They ranged in gestational age from 24 to 37 (median 27) weeks and were 1-39 (median 4) days old. Shunt and reduced VA/Q were derived from their effects on the relation between inspired oxygen...

  7. Levoatriocardinal Vein: An Unusual Cause of Right-to-Left Shunting

    Directory of Open Access Journals (Sweden)

    Nilima Shet

    2014-01-01

    Full Text Available We present a case demonstrating an anomalous vessel connecting the left brachiocephalic vein and the left superior pulmonary vein, found incidentally on computed tomography (CT imaging. This pulmonary-systemic venous connection, known as a levoatriocardinal vein, is a rare anomaly. In previous descriptions, this vessel has typically been associated with left-to-right shunt. Here, we describe the magnetic resonance imaging (MRI and CT findings in a case with right-to-left shunting through the anomalous vessel likely secondary to elevated right cardiac pressure.

  8. Implementation of FFT Algorithm using DSP TMS320F28335 for Shunt Active Power Filter

    Science.gov (United States)

    Patel, Pinkal Jashvantbhai; Patel, Rajesh M.; Patel, Vinod

    2016-07-01

    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.

  9. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Bercu, Zachary L., E-mail: zachary.bercu@mountsinai.org; Sheth, Sachin B., E-mail: sachinsheth@gmail.com [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States); Noor, Amir, E-mail: amir.noor@gmail.com [The George Washington University School of Medicine and Health Sciences (United States); Lookstein, Robert A., E-mail: robert.lookstein@mountsinai.org; Fischman, Aaron M., E-mail: aaron.fischman@mountsinai.org; Nowakowski, F. Scott, E-mail: scott.nowakowski@mountsinai.org; Kim, Edward, E-mail: edward.kim@mountsinai.org; Patel, Rahul S., E-mail: rahul.patel@mountsinai.org [Icahn School of Medicine at Mount Sinai, Division of Interventional Radiology (United States)

    2015-10-15

    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.

  10. [The radiographic appearances following correction of left-to-right shunts (author's transl)].

    Science.gov (United States)

    Grünberg, G

    1978-12-01

    Amongst 22 patients with corrected left-to-right shunts, a diminution in heart size and reduction in central pulmonary arteries and pulmonary plethora was found in about half the patients. A good operative result can be expected, particularly in younger patients with less severe lesions, where the vessels had not been subjected to a high pressure for a long period. The failure of vessels to return to normal is assurmed to be due to changes in the vessel walls. Possible causes for persistent cardiomegaly are, in addition to persistent shunts, coronary artery disease, obesity, inadequate digitalisation and aortic and mitral insufficiency. PMID:153276

  11. Pancreaticoportal Fistula and Disseminated Fat Necrosis After Revision of a Transjugular Intrahepatic Portosystemic Shunt

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Seth J., E-mail: kleins@mir.wustl.edu; 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)

    2013-04-15

    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.

  12. Unusual cause for ventriculoperitoneal shunt failure: Carcinoma breast compressing distal catheter

    Directory of Open Access Journals (Sweden)

    Roka Yam

    2010-01-01

    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.

  13. A new method for palliation of malignant obstructive jaundice utilizing a peritoneo-venous shunt pump.

    Science.gov (United States)

    Araki, K; Kure, M; Kobayasi, M; Sugito, M; Ogata, T

    1994-02-01

    A new simple palliative method for use in malignant obstructive jaundice is presented. This method is particularly effective in the prevention of ascending infections. The method consists of interposing a one-way flow shunt pump (peritoneo-venous shunt pump) between a bile catheter and a jejunal catheter. Four patients were treated with this new method. Jaundice improved significantly in all patients. They had a much better quality of life with no serious complications during the terminal course. This less invasive and safe procedure is preferred for patients who have extrahepatic biliary obstruction due to incurable malignant tumors. PMID:7513676

  14. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    International Nuclear Information System (INIS)

    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

  15. Evaluation of Intrapulmonary Shunt Alterations at Different Oxygen Concentrations and Oxygenation Parameters

    OpenAIRE

    Zerrin Demirtürk; Ecder Özenç; Sibel Buluç Bulğen

    2015-01-01

    Aim: The aim of the current study was to evaluate the relationship of intrapulmonary shunt with FiO2 alterations in patients treated with mechanical ventilation in intensive care unit for extrapulmonary disorders. Also, we aimed to assess the role of correlation between shunt ratio and PaO2/FiO2, PaO2/PAO2, P(A-a) O2 values in determining the treatment strategies. Methods: Twenty patients between ages of 19 and 75 years, requiring mechanical ventilation were enrolled into...

  16. Current diagnosis and management of post-transjugular intrahepatic portosystemic shunt refractory hepatic encephalopathy.

    Science.gov (United States)

    Pereira, Keith; Carrion, Andres F; Martin, Paul; Vaheesan, Kirubahara; Salsamendi, Jason; Doshi, Mehul; Yrizarry, Jose M

    2015-12-01

    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. PMID:26332169

  17. Acute pancreatitis

    OpenAIRE

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    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 ingest...

  18. Acute pancreatitis

    OpenAIRE

    Bo-Guang Fan; Åke Andrén-Sandberg

    2010-01-01

    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....

  19. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Science.gov (United States)

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    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. Co-Localization of GABA Shunt Enzymes for the Efficient Production of Gamma-Aminobutyric Acid via GABA Shunt Pathway in Escherichia coli.

    Science.gov (United States)

    Pham, Van Dung; Somasundaram, Sivachandiran; Park, Si Jae; Lee, Seung Hwan; Hong, Soon Ho

    2016-04-28

    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.

  1. Acute pancreatitis

    Directory of Open Access Journals (Sweden)

    Bo-Guang Fan

    2010-01-01

    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.

  2. Acute pancreatitis

    Directory of Open Access Journals (Sweden)

    Bo-Guang Fan

    2010-05-01

    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. Cerebrospinal fluid pulse pressure amplitude during lumbar infusion in idiopathic normal pressure hydrocephalus can predict response to shunting

    Directory of Open Access Journals (Sweden)

    Brean Are

    2010-02-01

    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

  4. Evaluation of usefulness of scintigraphic imaging in diagnosis of intrathecal drug delivery system malfunction – a preliminary report

    International Nuclear Information System (INIS)

    Implantable intrathecal drug delivery systems (IDDS) are basic tool enabling chronic intrathecal pharmacotherapy. Lack of expected clinical results of IDDS therapy necessitates search for the cause with the help of diagnostic imaging methods among other things. Beside radiological techniques, it is also possible to visually assess IDDS systems by nuclear medicine methods. In this study we assess utility of radioisotopic methods in differential diagnosis of failure of therapy with IDDS systems. Scintigraphic studies were performed in selected patients with neurological diseases associated with spasticity, who had IDDS system implanted and were unable to maintain satisfying clinical effect of inrathecally infused baclofen. After emptying the IDDS system of the drug, radiotracer (99mTc-DTPA) solution was injected into the pump reservoir. Subsequently, a series of scintigraphic images was registered, demonstrating passage and distribution of the infused radiotracer. In all investigated cases, scintigraphic study resulted in acquiring relevant additional diagnostic information. Normal or disrupted distribution of radiotracer in spinal canal allowed for a diagnosis drug resistance or demonstrated presence of arachnoid adhesions respectively. Early appearance of radiotracer in blood was considered a proof of leak. Our examinations had decisive influence on further patient treatment, allowing for diagnosis of drug resistance in one patient or complication related to IDDS system in three other cases including breakage of a catheter, pump malfunction and arachnoid adhesions. Scintigraphic methods carry significant amount of information facilitating final diagnosis of the cause of IDDS therapy failure. They should become an important element complementing the diagnostic strategy in patients with suspected failure of intrathecal drug administration systems. Interpretation of radioisotopic studies, since they are purely functional, must be performed in strict relation to

  5. Almost periodic solution of shunting inhibitory cellular neural networks with time-varying delay

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xia; Cao Jinde

    2003-07-28

    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.

  6. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    Science.gov (United States)

    Cardella, Davide; Celli, Paolo; Gonella, Stefano

    2016-08-01

    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.

  7. Percutaneous arteriovenous shunting in patients with severe COPD. A new interventional radiological treatment

    International Nuclear Information System (INIS)

    Purpose: The aim of this study was to evaluate the technical feasibility and safety of a new interventional radiological technique to create a shunt percutanously between the external iliac vein and artery in patients with severe COPD. Materials and Methods: 40 patients were included in this multicenter trial. In 38 patients the artery was punctured from the vein using a novel crossing needle. A special delivery system was used to implant a novel nitinol device (ACS, ROX Medical) between the artery and the vein to maintain a 4 mm calibrated and structured fistula between the two vessels. Results: Shunt implantation was successful in 38 patients. The perfused arteriovenous shunts could be well documented in DSA and the diameter was measured between 3 and 4 mm in all cases. Peri-interventional non-flow-limiting dissection of the iliac artery occurred in one patient. Post-interventional venous bleeding in two patients was treated successfully by local compression. In one patient a peripheral artery thrombembolism was successfully treated by thrombolysis. Conclusion: The new interventional radiological technique to create an arteriovenous shunt in the iliac vessels presented in this study has proven to be feasible and safe. (orig.)

  8. Role of kinetic inductance in transport properties of shunted superconducting nanowires.

    Science.gov (United States)

    Lin, Shi-Zeng; Roy, Dibyendu

    2013-08-14

    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.

  9. Negative capacitance shunt damping system with optimized characteristics for use with piezoelectric transducers

    Science.gov (United States)

    Pohl, Martin

    2014-03-01

    For ecologic sustainability and decreasing reserves of fossile energy sources, fuel efficiency is a major concern especially for passenger aircraft. Therefore, lightweight structures made from carbon fiber plastics offer great potential. But when used for panel-like structures, they have the disadvantage of lower damping and coincidence frequencies compared to conventional differential metal constructions. Both aspects lead to an increased vibration level and by this a higher noise radiation. Because of this, special noise and vibration treatment is needed to ensure passenger cabin comfort. Besides passive damping and active structural acoustic control (ASAC), piezoelectric shunt damping is investigated. Due to its broadband performance, the negative capacitance shunt can be used for multimode systems with varying eigenfrequencies. These shunts are usually built with operational amplifiers and passive components as resistors and capacitors. This setup is sufficient for laboratory tests at low excitation levels. In fact, it is not capable of accessing the full voltage amplitude of common piezoelectric transducers, because most operational amplifiers only deliver +/-15V maximum output voltage. Therefore an improved setup is presented in this paper, which addresses the specific voltage requirements of a common piezoelectric transducer to achieve best performance. It comprises a tailored power source and an appropriate concept for the negative capacitance shunt hardware. This new hardware only uses standard operational amplifiers together with a high voltage power amplifier to cover the whole operating range of a piezoelectric transducer. A demonstrator board is developed and experimentally investigated at a test structure. Finally, the results are compared to a conventional setup.

  10. A novel technique to treat acquired Chiari I malformation after supratentorial shunting

    NARCIS (Netherlands)

    Potgieser, Adriaan R E; Hoving, Eelco W

    2016-01-01

    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

  11. The G6. A heavy-duty, six-wheeled shunting locomotive

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Tim [Vossloh Locomotives GmbH, Kiel (Germany). Development and Standardisation Group

    2010-05-15

    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.)

  12. Catheterobronchial fistula due to vena cava superior thrombosis as a late complication of ventriculoatrial shunt.

    Science.gov (United States)

    Parízek, J; Nytra, T; Zemánková, M; Eliás, P; Sercl, M; Nĕmecková, J; Jakubec, J

    1994-09-01

    A case of a catheterobronchial fistula as a rare late complication of a ventriculoatrial shunt is reported. The ventriculoatrial shunt was implanted in a 4-month-old boy suffering from extreme postinfectious hydrocephalus. During the following years, twelfth nerve palsy on the right, vertebralgias, and salty taste sensations in the mouth associated with intermittent coughing and swelling of the neck and supraclavicular region on the right side developed. Valvography established a diagnosis of fistula 12 years after the implantation of a shunt. Ultrasonography of the neck and mediastinum and contrast-enhanced dynamic computed tomographic scanning demonstrated a catheterobronchial fistula to the subsegmental bronchus of the anterior segment of the right upper lung lobe, a thrombosis of the right internal jugular and both right and left brachiocephalic veins and the superior vena cava, and an extensive collateral venous system mainly draining into the azygos vein. Normalization of cerebrospinal fluid and blood flow and pressure allowed extraction of the "atrial" catheter without complications. One year after surgery the boys is in good health and without signs of shunt dependence. PMID:7842439

  13. Electrochemical etching of molybdenum for shunt removal in thin film solar cells

    NARCIS (Netherlands)

    Hovestad, A.; Bressers, P.M.M.C.; Meertens, R.M.; Frijters, C.H.; Voorthuijzen, W.P.

    2015-01-01

    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. Alteration of brain viscoelasticity after shunt treatment in normal pressure hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2012-03-15

    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.)

  15. Analysis of postural sway in patients with normal pressure hydrocephalus: effects of shunt implantation

    Directory of Open Access Journals (Sweden)

    Czerwosz L

    2009-12-01

    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.

  16. Biocompatibility of a novel tissue connector for fixation of tracheostoma valves and shunt valves

    NARCIS (Netherlands)

    Geertsema, AA; Schutte, HK; van Leeuwen, MBM; Rakhorst, G; Schakenraad, JM; van Luyn, MJA; Verkerke, GJ

    1999-01-01

    Rehabilitation after laryngectomy often includes the use of a shunt valve and a tracheostoma valve to restore voice. To improve the fixation method of these valves, a new tissue connector has been developed, basically consisting of a ring that will be integrated into surrounding tracheal soft tissue

  17. Experimental results of the tracheoesophageal tissue connector for improved fixation of shunt valves in laryngectomized patients

    NARCIS (Netherlands)

    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.

    2006-01-01

    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

  18. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    Science.gov (United States)

    Cardella, Davide; Celli, Paolo; Gonella, Stefano

    2016-08-01

    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.

  19. Outcome of endoscopic third ventriculostomy and Chhabra shunt system in noncommunicating non-tumor childhood hydrocephalus

    Directory of Open Access Journals (Sweden)

    O E Idowu

    2009-01-01

    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.

  20. [Peritoneojugular shunt in the treatment of idiopathic ascites in the hemodialyzed patient: a clinical case].

    Science.gov (United States)

    Massari, R; Marinelli, S; Fulgente, R; Summa, R

    1995-01-01

    The case of an uremic patient receiving dialytic treatment, who also had an hydiopatic ascites, probably due to peritoneal hyper-waterproofing, is described. Peritoneo-venous shunt was positioned with good result. Generally, similar clinical situations such a therapy is as valid as other commonly used methods. PMID:8706186

  1. Within-session and between-session variability of haemodialysis shunt flow measurements

    NARCIS (Netherlands)

    Huisman, RM; van Dijk, M; de Bruin, C; Loonstra, J; Sluiter, WJ; Zeebregts, CJ; van den Dungen, JJAM

    2005-01-01

    Background. Knowledge of the variabilty of a measurement method is essential for its clinical application. We investigated the variability of shunt flow measurements, since this is a relatively neglected area in the literature. In particular, no direct comparison of between-session and within-sessio

  2. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural waves

    Science.gov (United States)

    Chen, Y. Y.; Hu, G. K.; Huang, G. L.

    2016-10-01

    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.

  3. Existence of Periodic Solutions for Shunting Inhibitory Cellular Neural Networks with Neutral Delays

    Directory of Open Access Journals (Sweden)

    Ninghua Chen

    2013-01-01

    Full Text Available This paper considers the existence of periodic solutions for shunting inhibitory cellular neural networks (SICNNs with neutral delays. By applying the theory of abstract continuation theorem of k-set contractive operator and some analysis technique, a new result on the existence of periodic solutions is obtained.

  4. Existence of Periodic Solutions for Shunting Inhibitory Cellular Neural Networks with Neutral Delays

    OpenAIRE

    Ninghua Chen

    2013-01-01

    This paper considers the existence of periodic solutions for shunting inhibitory cellular neural networks (SICNNs) with neutral delays. By applying the theory of abstract continuation theorem of k-set contractive operator and some analysis technique, a new result on the existence of periodic solutions is obtained.

  5. [Isolated left ventricular--right atrial shunt after blunt chest trauma (author's transl)].

    Science.gov (United States)

    Kreuzer, E; Beyer, J

    1978-12-01

    A case of left-ventricular-right-atrial septal defect secundary to blunt chest trauma is described. The etiology of this type of septal defect, e. g. congenital, following aortic and mitral valve replacement, endocarditis and trauma, is discussed. Early defect closure is recommended in the presence of significant shunt volume. PMID:751280

  6. Sternotomy approach for modified Blalock-Taussig shunt: is it a safe option?

    Science.gov (United States)

    Kandakure, Pramod Reddy; Dharmapuram, Anil Kumar; Ramadoss, Nagarajan; Babu, Vivek; Rao, Ivatury Mrityunjaya; Murthy, Kona Samba

    2010-08-01

    Central aorta-pulmonary artery shunts have fallen into disfavor because of shunt thrombosis and congestive heart failure, and a modified Blalock-Taussig shunt via thoracotomy can lead to pulmonary artery hypoplasia and distortion. We reviewed the outcomes of a modified Blalock-Taussig shunt by a sternotomy approach in 20 infants from July 2007 to October 2009. Their mean age was 5.79 months, and median weight was 5.4 kg. A 4-mm graft was placed in 11 patients, a 5-mm graft in 8, and a 3.5-mm graft in 1. There was no incidence of sepsis, seroma, or phrenic nerve palsy. There was one hospital death. The mean hospital stay was 10.4 +/- 4.3 days (range, 8-15 days). The mean oxygen saturation at discharge was 89% (range, 81%-93%). The sternotomy approach is technically easier to perform, cosmetically preferable, and probably hemodynamically superior. Correction of branch pulmonary stenosis is easily incorporated into this procedure. The theoretical disadvantage of this method is a potential technical difficulty with sternal reentry for subsequent procedures. PMID:20719789

  7. A Multi-Mode Blade Damping Control using Shunted Piezoelectric Transducers with Active Feedback Structure

    Science.gov (United States)

    Choi, Benjamin; Morrison, Carlos; Min, James

    2009-01-01

    The Structural Dynamics and. Mechanics branch (RXS) is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this presentation, only one shunted PE transducer was used to demonstrate active control of multi-mode blade resonance damping on a titanium alloy (Ti-6A1-4V) flat plate model, regardless of bending, torsion, and 2-stripe modes. This work would have a significant impact on the conventional passive shunt damping world because the standard feedback control design tools can now be used to design and implement electric shunt for vibration control. In other words, the passive shunt circuit components using massive inductors and. resistors for multi-mode resonance control can be replaced with digital codes. Furthermore, this active approach with multi patches can simultaneously control several modes in the engine operating range. Dr. Benjamin Choi presented the analytical and experimental results from this work at the Propulsion-Safety and. Affordable Readiness (P-SAR) Conference in March, 2009.

  8. Pictorial essay: trans-jugular intra-hepatic porto-systemic shunt (TIPS)

    International Nuclear Information System (INIS)

    TIPS is an interventional radiologic method of creating a portosystemic shunt by percutaneous means. It is a relatively new weapon in the armamentarium of the management of portal hypertension with variceal bleeding or intractable ascites. Using needles, angioplasty balloon catheters and expandable metallic stents, a shunt is established directly inside the liver parenchyma connecting a large hepatic vein with a main portal vein branch. Depending on the diameter of the expandable stent used, the created TIPS diverts various amounts of portal blood into the systemic circulation and results in significant portal decompression, cessation of hemorrhage from esophageal varices and resolution of ascites. TIPS is not only an effective and safe alternative to shunt surgery but is life saving in cases of variceal hemorrhage. The use of TIPS seems to be a valid alternative to surgery and has several advantages over either esophageal transection or surgical shunts. TIPS avoids a general anesthetic, laparotomy, and disruption of the hepatic venous system that may adversely affect subsequent hepatic transplantation. TIPS has been performed on patients without interfering with successful transplantation

  9. Numerical bifurcation analysis of distance-dependent on-center off-surround shunting neural networks.

    NARCIS (Netherlands)

    P.C.M. Molenaar; M.E.J. Raijmakers; H.L.J. van der Maas

    1996-01-01

    On-center off-surround shunting neural networks are often applied as models for content-addressable memory (CAM), the equilibria being the stored memories. One important demand of biological plausible CAMs is that they function under a broad range of parameters, since several parameters vary due to

  10. Evaluation of hepatic steatosis in dogs with congenital portosystemic shunts using Oil Red O staining.

    Science.gov (United States)

    Hunt, G B; Luff, J A; Daniel, L; Van den Bergh, R

    2013-11-01

    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.

  11. Accurate phasor measurement for transmission line protection in the presence of shunt capacitor banks

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2007-10-15

    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)

  12. Noncirrhotic Portal Hypertension due to Nodular Regenerative Hyperplasia Treated with Surgical Portacaval Shunt

    Directory of Open Access Journals (Sweden)

    Lisa M. Louwers

    2012-01-01

    Full Text Available Nodular regenerative hyperplasia (NRH is an uncommon condition, but an important cause of noncirrhotic intrahepatic portal hypertension (NCIPH, characterized by micronodules of regenerative hepatocytes throughout the liver without intervening fibrous septae. Herein, we present a case of a thirty-seven-year-old female with systemic lupus erythematosus (SLE who was discovered to have significant esophageal varices on endoscopy for dyspepsia. Her labs revealed a slight elevation in the alkaline phosphatase and mild thrombocytopenia. Abdominal MRI revealed seven focal hepatic masses, splenomegaly, no ascites, and a patent portal vein. Ultrasound-guided core biopsy was reported as focal nodular hyperplasia. However, her varices persisted despite treatment with beta-blockers and four additional upper endoscopies with banding. She was subsequently referred for a surgical opinion. At that time, given her history of SLE, azathioprine use, and portal hypertension, suspicion for NRH was raised. Given her normal synthetic function and lack of parenchymal liver disease, the patient was offered surgical shunting. During shunt surgery, a liver wedge biopsy was also performed and this confirmed NRH. An upper endoscopy six weeks after shunting verified complete resolution of varices. Currently, fifteen months after surgery duplex ultrasonography demonstrates shunt patency and the patient is without recurrence of her portal hypertension.

  13. Bilateral Fetal Hydrothorax Requiring Intrauterine Fetal Thoracoamniotic Shunts: Anesthetic Considerations and Management

    OpenAIRE

    Hache, John J.; Emery, Stephen P.; Vallejo, Manuel C.

    2009-01-01

    After prenatal diagnosis of bilateral fetal hydrothorax, ascites, and polyhydramnios, bilateral thoracoamniotic shunts were placed at 29 weeks gestation using an ultrasound-guided, minimally invasive technique. Anesthetic care was managed using intravenous sedation and local anesthesia infiltration. The anesthetic considerations for such procedures are discussed.

  14. Bilateral Fetal Hydrothorax Requiring Intrauterine Fetal Thoracoamniotic Shunts: Anesthetic Considerations and Management

    Directory of Open Access Journals (Sweden)

    John J. Hache

    2009-01-01

    Full Text Available After prenatal diagnosis of bilateral fetal hydrothorax, ascites, and polyhydramnios, bilateral thoracoamniotic shunts were placed at 29 weeks gestation using an ultrasound-guided, minimally invasive technique. Anesthetic care was managed using intravenous sedation and local anesthesia infiltration. The anesthetic considerations for such procedures are discussed.

  15. The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit

    Science.gov (United States)

    Birenbaum, Jeffrey Scott

    While quantum computation has the potential to revolutionize the scientific community, to date no architecture has been developed which offers the necessary combination of high coherence times and massive scalability. Superconducting flux qubits satisfy the second requirement well but to date useful devices are limited to coherence times of typically only a few mus. In this dissertation we examine the possibilities of improving the coherence performance of the flux qubit to the levels required for fault-tolerant quantum computation. We find that coherence times for many devices are limited by photon-induced quasiparticles and mitigation of these quasiparticles increases coherence times by more than a factor of two. Beyond this, however, we find little improvement in flux qubit performance compared to prior results. Despite improved fabrication techniques and varied device designs we find flux qubit coherence times are still typically below 5 mus. Furthermore, wide device-to-device variations are observed which prevent effective scaling of the flux qubit to quantum information circuits. Based on the proposal by You, et al. we develop of a capacitively-shunted version of the flux qubit called the C-shunt flux qubit. With the addition of a capacitive shunt across the small junction of the flux qubit we are able to reduce the amplitude sensitivity to both charge and flux noise by more than a factor of three. The result is a predicted ten-fold enhancement in the coherence times compared to the unshunted flux qubit. At the same time we preserve much of the anharmonicity of the flux qubit resulting in a device with coherence times comparable to modern transmons but with a factor of four better anharmonicity and more flexible coupling configurations. By using a high-quality MBE aluminum shunt process on an annealed sapphire substrate coupled with a more conventional electron-beam-evaporated aluminum Josephson junction process we fabricate hybrid C-shunt flux qubits. We

  16. 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

    Institute of Scientific and Technical Information of China (English)

    梁玉敏; 高国一; 包映晖; 丁圣豪; 潘耀华; 吴海波; 陈磊; 江基尧

    2011-01-01

    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

  17. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing.

    Science.gov (United States)

    Venkataraman, Pranav; Browd, Samuel R; Lutz, Barry R

    2016-09-01

    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. PMID:27203135

  18. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing.

    Science.gov (United States)

    Venkataraman, Pranav; Browd, Samuel R; Lutz, Barry R

    2016-09-01

    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.

  19. Indication for shunt operation of normal pressure hydrocephalus. Combined assessment of infusion test and dynamic CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Jinnai, Takahiro; Nagao, Seigo [Kagawa Medical Univ., Miki (Japan); Kuyama, Hideyuki

    2000-03-01

    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)

  20. Indication for shunt operation of normal pressure hydrocephalus. Combined assessment of infusion test and dynamic CT scan

    International Nuclear Information System (INIS)

    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)

  1. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    Science.gov (United States)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-08-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter ( r t), ratio of HAZ area on shunted and free side of nugget ( r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample ( r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  2. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt

    Directory of Open Access Journals (Sweden)

    Pickard John D

    2008-04-01

    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.

  3. Hepatopulmonary shunting in patients with primary and secondary liver tumors scheduled for radioembolization

    International Nuclear Information System (INIS)

    Purpose: In patients undergoing transarterial radioembolization (RE) of malignant liver tumors, hepatopulmonary shunts (HPS) can lead to nontarget irradiation of the lungs. This study aims at analyzing the HPS fraction in relation to liver volume, tumor volume, tumor-to-liver volume ratio, tumor vascularity, type of tumor, and portal vein occlusion. Materials and methods: In the presented retrospective study the percentage HPS fraction was calculated from SPECT/CT after infusion of Tc-99m macroaggregated albumin (Tc-99m MAA) into the proper hepatic artery of 233 patients evaluated for RE. Results: HPS fractions correlate very weakly with liver volume (r = 0.303), tumor volume (r = 0.345), and tumor-to-liver volume ratio (r = 0.340). Tumors with strong contrast enhancement (HPSmedian(range) = 11.7%(46.3%); n = 73) have significantly larger shunt fractions than tumors with little enhancement (HPS = 8.3%(16.4%); n = 61; p < 0.001). Colorectal cancer metastases (HPS = 10.6%(28.6%); n = 68) and hepatocellular cancers (HPS = 11.7%(39.4%); n = 63) have significantly larger HPS fractions than metastases from breast cancer (HPS = 7.4%(16.7%); n = 40; p = 0.012 and p = 0.001). Patients with compression (HPS = 13.9%(43.7%); n = 33) or tumor thrombosis (HPS = 15.8% (31.2%); n = 33) of a major portal vein branch have significantly higher degrees of shunting than patients with normal portal vein perfusion (HPS = 8.1% (47.0%); n = 167; both p < 0.001). The shunt fraction is largest in patients with HCC and thrombosis or occlusion of a major portal vein branch (HPS = 16.6% (31.0%); n = 32). Conclusion: The degree of hepatopulmonary shunting depends on the type of liver tumor, tumor vascularity, and portal vein perfusion. There is little to no correlation of HPS with liver volume, tumor volume, or tumor-to-liver volume ratio

  4. Acute respiratory failure after endoscopic third ventriculostomy: A case report and review of the literature

    OpenAIRE

    Elgamal, Essam A.; Mansoor Aqil

    2012-01-01

    Endoscopic third ventriculostomy (ETV) is a relatively safe procedure. However, postoperative acute respiratory failure may be fatal. The authors report an 8-month-old patient with obstructive hydrocephalus secondary to posterior fossa cyst, and Chiari malformation. After ETV he developed difficulty in breathing, and had to be reintubated and ventilated. The infant recovered fully after craniocervical decompression and insertion of cystoperitoneal shunt. We speculate that respiratory failure ...

  5. Vascular plug-assisted retrograde transvenous obliteration of portosystemic shunts for refractory hepatic encephalopathy: a case report.

    Science.gov (United States)

    Park, Jonathan K; Cho, Sung-Ki; Kee, Stephen; Lee, Edward W

    2014-01-01

    While balloon-assisted retrograde transvenous obliteration (BRTO) has been used for two decades in Asia for the management of gastric variceal bleeding, it is still an emerging therapy elsewhere. Given the shunt closure brought about by the procedure, BRTO has also been used for the management of portosystemic encephalopathy with promising results. Modified versions of BRTO have been developed, including plug-assisted retrograde transvenous obliteration (PARTO), where a vascular plug is deployed within a portosystemic shunt. To our knowledge, we present the first North American case of PARTO in the setting of a large splenorenal shunt for the management of portosystemic encephalopathy. PMID:24744943

  6. Field Experiments on 10 kV Switching Shunt Capacitor Banks Using Ordinary and Phase-Controlled Vacuum Circuit Breakers

    OpenAIRE

    Wenxia Sima; Mi Zou; Qing Yang; Ming Yang; Licheng Li

    2016-01-01

    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 ...

  7. Long Term Results (>5 Years) in Patients With Peritoneovenous Shunting for Intractable Ascites: Liver Function and Cancer Mortality

    OpenAIRE

    Franco, Dominique; Meakins, Jonathan L.; Wu, Andrew; Smadja, Claude; Bonnet, Patrick; Gouffier, Etienne; Campillo, Bernard

    1989-01-01

    This report is based on twenty-eight (26%) of 107 patients included in a protocol for prospective evaluation of elective peritoneo-venous shunting for intractable ascites in cirrhosis. These patients had no other procedures and survived more than 5 years after the operation. All patients were free of ascites except one in whom it was mild. One patient refused follow-up. Shunt patency was assessed in 23 patients. In 14 patients (60.9%), the shunt was obstructed and the superior vena cava was o...

  8. Acute two-compartment low pressure hydrocephalus--a case report.

    Science.gov (United States)

    Preuß, M; Evangelou, P; Hirsch, W; Reiss-Zimmermann, M; Fischer, L; Merkenschlager, A; Kieß, W; Siekmeyer, M; Meixensberger, J; Nestler, U

    2013-12-01

    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.

  9. An efficient method for monitoring the shunts in silicon solar cells during fabrication processes with infrared imaging

    Institute of Scientific and Technical Information of China (English)

    Zhang Lucheng; Xu Xinxiang; Yang Zhuojian; Sun Xiaopu; Xu Hongyun; Liu Haobin; Shen Hui

    2009-01-01

    , 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.

  10. Subdural haematoma complicating shunting for normal pressure hydrocephalus in the setting of concomitant antiplatelet medication - a report of 11 cases

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  11. Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report.

    Science.gov (United States)

    Chan, Andrew K; Birk, Harjus S; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W

    2016-07-07

    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.

  12. Ligation of Left Renal Vein for Spontaneous Splenorenal Shunt to Prevent Portal Hypoperfusion after Orthotopic Liver Transplantation

    Directory of Open Access Journals (Sweden)

    Lampros Kousoulas

    2013-01-01

    Full Text Available We report a case of recovered portal flow by ligation of the left renal vein on the first postoperative day after orthotopic liver transplantation of a 54-year-old female with alcoholic liver cirrhosis, chronic kidney failure, and spontaneous splenorenal shunt. After reperfusion, Doppler ultrasonography showed almost total diversion of the portal flow into the existing splenorenal shunt, but because of severe coagulopathy and diffuse bleeding, ligation of the shunt was not attempted. A programmed relaparotomy was performed on the first postoperative day, and the left renal vein was ligated just to the left of the inferior vena cava. Portal flows subsequently increased to 37 cm/sec, and the patient presented a good and stable liver function. We conclude that patients with known preoperative splenorenal shunts should be closely monitored, and if the portal flow becomes insufficient, ligation of the left renal vein should be attempted in order to optimize the portal perfusion of the liver.

  13. Safety and efficacy of 2-octyl-cyanoacrylate in the management of patients with gastric and duodenal varices who are not candidates for transjugular intrahepatic portosystemic shunts

    Science.gov (United States)

    Burdick, James; Trotter, James F.

    2016-01-01

    Gastric variceal bleeding is associated with significant morbidity and mortality in patients with portal hypertension and cirrhosis. Options are limited for patients who are not candidates for transjugular intrahepatic portosystemic shunts (TIPS). Cyanoacrylate injections have been reported to be efficacious in previous case series. The aim of this retrospective study was to report our single-center experience with the safety and efficacy of 2-octyl-cyanoacrylate in patients who were not TIPS candidates. Electronic medical records were reviewed for 16 patients who underwent a total of 18 esophagogastroduodenoscopies for acute gastric or duodenal variceal bleeding and secondary prophylaxis of gastric varices; 14 patients had cirrhosis with an average Model for End-Stage Liver Disease score of 16, and 2 patients had noncirrhotic portal hypertension. Primary endpoints of the study included early and delayed rebleeding rate, complications, and death or liver transplantation. The rebleeding rate (early or delayed) was 7%, and no complications were found. One death was reported (unrelated to the procedure). In conclusion, 2-octyl-cyanoacrylate is a safe and effective alternative for non-TIPS candidates who present with acute gastric variceal bleeding given its low rebleeding and complication rate.

  14. Creation of an iliac arteriovenous shunt lowers blood pressure in chronic obstructive pulmonary disease patients with hypertension.

    LENUS (Irish Health Repository)

    Faul, John

    2014-01-28

    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.

  15. New temporary internal introducer shunt for brain perfusion during total endovascular arch replacement with in situ fenestration technique.

    Science.gov (United States)

    Sonesson, Björn; Resch, Tim; Dias, Nuno; Malina, Martin

    2012-10-01

    Complete endovascular arch replacement by in situ fenestration technique requires maintenance of cerebral perfusion during the fenestration procedure by an extracorporeal femoral-carotid bypass. The bypass has the disadvantages of being invasive, requiring a pump, and shunting blood extracorporeally. This report describes bench testing and an in vivo experimental animal setup with an endovascular, temporary introducer shunt. This technique represents an adjunctive step toward a complete endovascular repair for the aortic arch. PMID:22857810

  16. Thoraco-amniotic shunting for fetal pleural effusion--a case series.

    LENUS (Irish Health Repository)

    Walsh, J

    2011-11-15

    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.

  17. Analytical theory of DC SQUID with a resistively shunted inductance driven by thermal noises

    Institute of Scientific and Technical Information of China (English)

    Lü Hai-Feng; Gu Jiao; Huang Xin-Tang

    2005-01-01

    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.

  18. On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

    Science.gov (United States)

    Davis, Craig R.; Waldman, Frank A.

    1993-01-01

    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.

  19. Simulation Research of Transient Over-voltage on High-voltage Shunt Capacitor Banks

    Institute of Scientific and Technical Information of China (English)

    HU Quan-wei; ZHOU Xing-xing; SI Wen-rong; ZHANG Yang; LI Jur-hao; LI Yan-ming

    2011-01-01

    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.

  20. Application of VSC-HVDC with Shunt Connected SMES for Compensation of Power Fluctuation

    Science.gov (United States)

    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.