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Malfunction
Kinds of Malfunction Selected AbstractsTricuspid Valve Malfunction and Ventricular Pacemaker Lead: Case Report and Review of the LiteratureECHOCARDIOGRAPHY, Issue 8 2006Said B. Iskandar M.D. Pacemaker implantation can be associated with several complications, including myocardial perforation with or without pericardial effusion, venous thrombosis, vegetations of the tricuspid valve (TV) or pacing lead, and tricuspid regurgitation (TR). The TR is thought to be derived from deformity or perforation of the TV by the pacing lead or secondary to atrioventricular discordance with asynchronous ventricular pacing. Severe TR can be deleterious to the patient because it raises the central venous pressure by increasing the right sided preload. Chronically, the increase in right sided blood volume can result in an increase in the right atrial pressure leading to a decrease in venous return and low cardiac output. Severe TR from leaflet adhesion to the pacemaker lead has not been reported before. With the aging of the population and the expanding use of pacemakers and implantable cardioverter defibrillators (ICD) in clinical practice, this complication may be seen more frequently. We present a patient diagnosed with severe TR, years after his pacemaker implantation. His TR was thought to be caused by adhesion of the tricuspid valve to his pacemaker lead. [source] Apparent Ventricular Lead Malfunction,What is the Mechanism?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2009KRISHNAKUMAR NAIR M.D. [source] Failure To Pace: Pacemaker Malfunction?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2008ANTONIO NAVARRETE M.D. [source] Implantable Cardioverter-Defibrillator Malfunction due to Mechanical Failure of the Header ConnectionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2004R. ANDREW PICKETT III M.D. Four cases of ICD system malfunction occurring within the Medtronic Marquis family over a limited time frame are reported. These cases shared a common element of defective connections between the header post and the right ventricular pace/sense terminal pin that required intervention and reconnection. Inappropriate shocks occurred in two cases. The circumstances of these cases provide important information about the potential difficulties with these devices and highlight the deficiencies of the current system in tracking and analyzing device-related problems. [source] Ethanol-Induced Malfunction of Neutrophils Respiratory Burst on Patients Suffering From Alcohol DependenceALCOHOLISM, Issue 10 2008Dirk Breitmeier Background:, Polymorphonuclear, neutrophil granulocytes (PMN) play a major role in the control of infections, and people who abuse alcohol are susceptible to infections. Resistance against infections ensues intracellularly following initial phagocytosis of microorganisms with the oxygen-dependent respiratory burst, the key enzyme of which is the respiratory burst oxidase, whereby oxygen radicals are produced for microbial destruction. To date there is insufficient information available in connection with the process of impaired defence against infection in patients suffering from alcohol dependence. Therefore, our investigation was carried out to determine the influence of alcohol exposition on the formation of oxygen radicals and the respiratory burst. Methods:, 4.5 ml of whole blood was taken from 10 healthy adults and 10 patients suffering from alcohol dependence. An additional 3.5 ml of whole blood was taken from the alcoholic patients for determination of the blood alcohol concentration. The respiratory burst of PMN was tested using the Four-Colour-Continuous Flow Cytometer. Each experimental procedure consisted of 4 test samples [negative controls, Escherichia coli, FMLP-supplement (N-formyl-l-methionyl-l-leucyl-l-phenylalanin), PMA-supplement (phorbol-12-myristate-13-acetate)]. Differing concentrations of ethanol were also introduced to each of the tests performed (0.20 to 4.00 g/l). Results:, Ethanol revealed a marked decrease of burst activity in those patients suffering from alcoholism with increased alcohol concentration. A dependence between the burst activity and the ethanol concentration was seen to be statistically significant. This effect was only evident after stimulation with E. coli and FMLP in those patients with alcohol dependence. Conclusion:, The results presented in this study show an impairment in the function of PMN in those patients addicted to alcohol due to the decrease in burst activity. In view of the results of the different stimuli, the second-messenger effects were not evident. A clarification of this phenomenon could well be assumed as an allosteric receptor effect on the burst oxidase, namely, a direct effect on the phagocytosis interaction between circulating granulocytes and causative organisms. [source] Reliabilism, Proper Function, and Serendipitous MalfunctionPHILOSOPHICAL INVESTIGATIONS, Issue 1 2007Adrian Bardon Alvin Plantinga's externalist analysis of epistemic warrant centres on the proper function of the relevant belief-forming mechanism, where proper function is fixed relative to the design plan of the organism in question. He has set this analysis against reliabilism, the other leading externalist contender for the analysis of warrant. Though Plantinga's discussion advances the field of epistemology in a number of important ways, his treatment of warrant is limited by his assumption of creationism in his understanding of design and function. Further, analyses of epistemic warrant focusing on function over reliability either fail at handling problem cases reliabilism can handle, or fail to improve on problem cases for reliabilism. Thus no proper functionalist analysis like Plantinga's can supersede a well-constructed reliabilist analysis. [source] Thrombolytic Therapy with Tissue Plasminogen Activator for the Treatment of Nonstructural Malfunction of Bileaflet Cardiac Valve ProsthesesARTIFICIAL ORGANS, Issue 5 2002Hideki Teshima Abstract: This study was conducted to determine the effect of thrombolytic therapy with tissue plasminogen activator (t-PA) for nonstructural malfunction of bileaflet cardiac valve prostheses. Twenty-seven patients with bileaflet prosthetic valve malfunction diagnosed by a combination of cineradiography and transthoracic echocardiography were treated with the administration of intravenous t-PA. The treatment resulted in complete success in 55.6% (15 of 27), partial success in 22.2% (6 of 27), and no change in 22.2% (6 of 27). In the complete success and partial success groups, the condition of the patients in 85.7% (18 of 21) of the cases improved within 24 h after the administration of t-PA. Six cases in whom thrombolytic therapy was instituted more than 1 month (ranged from 1 to 38 months, mean 14.7 months) after the diagnosis of prosthetic valve malfunction showed significantly less effectiveness of thrombolytic therapy with t-PA. Only one patient (3.7%) had a major complication (thromboembolism) after t-PA treatment. The results suggest that thrombolytic therapy with t-PA in patients with nonstructural malfunction of bileaflet cardiac valve prostheses is effective with low incidence of complication when the treatment is instituted early after the diagnosis. [source] Toward a Consensus Model of the hERG Potassium ChannelCHEMMEDCHEM, Issue 3 2010Anna Stary Dr. Abstract Malfunction of hERG potassium channels, due to inherited mutations or inhibition by drugs, can cause long QT syndrome, which can lead to life-threatening arrhythmias. A three-dimensional structure of hERG is a prerequisite to understand the molecular basis of hERG malfunction. To achieve a consensus model, we carried out an extensive analysis of hERG models based on various alignments of helix,S5. We analyzed seven models using a combination of conventional geometry/packing/normality validation methods as well as molecular dynamics simulations and molecular docking. A synthetic test set with the X-ray crystal structure of Kv1.2 with artificially shifted S5 sequences modeled into the structure served as a reference case. We docked the known hERG inhibitors (+)-cisapride, (S)-terfenadine, and MK-499 into the hERG models and simulation snapshots. None of the single analyses unambiguously identified a preferred model, but the combination of all three revealed that there is only one model that fulfils all quality criteria. This model is confirmed by a recent mutation scanning experiment (P. Ju, G. Pages, R.,P. Riek, P.,C. Chen, A.,M. Torres, P.,S. Bansal, S. Kuyucak, P.,W. Kuchel, J.,I. Vandenberg, J. Biol. Chem. 2009, 284, 1000,1008).1We expect the modeled structure to be useful as a basis both for computational studies of channel function and kinetics as well as the design of experiments. [source] Pacemaker Malfunctions in Danon's DiseasePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2008ELENA MARRAS M.D. We describe a case of a 30-year-old man with Danon's disease, an X-linked genetic disorder due to deficiency of lysosomal-associated membrane protein 2 with secondary intracytoplasmatic glycogen and autophagic material storage. This disease is characterized by skeletal muscle involvement, mental retardation, ophthalmic abnormalities, and cardiac disease. In this patient, cardiac involvement was characterized by hypertrophic cardiomyopathy in young age, preexcitation, and parossistic atrioventriular block. The patient underwent to an implantable cardioverter defibrillator implantation for conduction disorders and for primary prevention of sudden death, a frequent event in Danon's disease. This case report describes cardiac involvement with conduction disorders and multiple pacemaker malfunctions in Danon's disease. [source] Topography of a 2.0 Å structure of ,1 -antitrypsin reveals targets for rational drug design to prevent conformational diseasePROTEIN SCIENCE, Issue 7 2000Peter R. Elliott Abstract Members of the serpin family of serine proteinase inhibitors play important roles in the inflammatory, coagulation, fibrinolytic, and complement cascades. An inherent part of their function is the ability to undergo a structural rearrangement, the stressed (S) to relaxed (R) transition, in which an extra strand is inserted into the central A ,-sheet. In order for this transition to take place, the A sheet has to be unusually flexible. Malfunctions in this flexibility can lead to aberrant protein linkage, serpin inactivation, and diseases as diverse as cirrhosis, thrombosis, angioedema, emphysema, and dementia. The development of agents that control this conformational rearrangement requires a high resolution structure of an active serpin. We present here the topology of the archetypal serpin ,1 -antitrypsin to 2 Å resolution. This structure allows us to define five cavities that are potential targets for rational drug design to develop agents that will prevent conformational transitions and ameliorate the associated disease. [source] Abductive Diagnosis Using Time-Objects: Criteria for the Evaluation of SolutionsCOMPUTATIONAL INTELLIGENCE, Issue 1 2001Elpida T. Keravnou Diagnostic problem solving aims to account for, or explain, a malfunction of a system (human or other). Any plausible potential diagnostic solution must satisfy some minimum criteria relevant to the application. Often there will be several plausible solutions, and further criteria will be required to select the "best" explanation. Expert diagnosticians may employ different, complex criteria at different stages of their reasoning. These criteria may be combinations of some more primitive criteria, which therefore should be represented separately and explicitly to permit their flexible and transparent combined usage. In diagnostic reasoning there is a tight coupling between the formation of potential solutions and their evaluation. This is the essence of abductive reasoning. This article presents an abductive framework for diagnostic problem solving. Time-objects, an association of a property and an existence, are used as the representation formalism and a number of primitive, general evaluation criteria into which time has been integrated are defined. Each criterion provides an intuitive yardstick for evaluating the space of potential solutions. The criteria can be combined as appropriate for particular applications to define plausible and best explanations. The central principle is that when time is diagnostically significant, it should be modeled explicitly to enable a more accurate formulation and evaluation of diagnostic solutions. The integration of time and primitive evaluation criteria is illustrated through the Skeletal Dysplasias Diagnostician (SDD) system, a diagnostic expert system for a real-life medical domain. SDD's notions of plausible and best explanation are reviewed so as to show the difficulties in formalizing such notions. Although we illustrate our work by medical problems, it has been motivated by consideration of problems in a number of other domains (fermentation monitoring, air and ground traffic control, power distribution) and is intended to be of wide applicability. [source] On-line hybrid test combining with general-purpose finite element softwareEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2006Tao Wang Abstract A new on-line hybrid test system incorporated with the substructuring technique is developed. In this system, a general-purpose finite element software is employed to obtain the restoring forces of the numerical substructure accurately. The restart option is repeatedly used to accommodate the software with alternating loading and analysis characteristic of the on-line test but without touching the source code. An eight-storey base-isolated structure is tested to evaluate the feasibility and effectiveness of the proposed test system. The overall structure is divided into two substructures, i.e. a superstructure to be analysed by the software and a base-isolation layer to be tested physically. Collisions between the base-isolation layer and the surrounding walls are considered in the test. The responses of the overall structure are reasonable, and smooth operation is achieved without any malfunction. Copyright © 2006 John Wiley & Sons, Ltd. [source] Essential role for ERK2 mitogen-activated protein kinase in placental developmentGENES TO CELLS, Issue 11 2003Naoya Hatano Background:, Extracellular signal-regulated kinase 2 (ERK2) has been implicated in cell proliferation, differentiation, and survival. However, its role in vivo remains to be determined. Results:, Here we show that the targeted disruption of the mouse ERK2 gene results in embryonic lethality by E11.5 and severe abnormality of the placenta. In these animals, the labyrinthine layer of the placenta is very thin and few foetal blood vessels are observed. ERK2 mutants can be rescued by the transgenic expression of ERK2, demonstrating that these abnormalities are caused by ERK2-deficiency. Although ERK2-deficient fetuses are much smaller than wild-type littermates, this seems to be secondary to malfunction of the placenta. When the placental defect is rescued by tetraploid-aggregation, ERK2-deficient foetuses grow as well as littermate controls. Conclusion:, These observations indicate that ERK2 is essential for placental development and suggest that ERK2 in the trophoblast compartment may be indispensable for the vascularization of the labyrinth. [source] The expression of tubulin polymerization promoting protein TPPP/p25, is developmentally regulated in cultured rat brain oligodendrocytes and affected by proteolytic stressGLIA, Issue 16 2008Olaf Goldbaum Abstract The tubulin polymerization-promoting protein (TPPP)/p25, was identified as a brain specific protein, is associated with microtubules (MTs) in vitro and can promote abnormal MT assembly. Furthermore it has aggregation promoting properties and is a constituent in pathological protein deposits of neurodegenerative diseases. In the brain, TPPP/p25, is present in myelinating oligodendrocytes. Here we show, using cultured rat brain oligodendrocytes, that TPPP/p25, expression is increasing during development in culture, and particularly in immature cells is associated with the centrosome. MT binding properties in oligodendrocytes are rather low, however, when MTs are disassembled by nocodazole, TPPP/p25, accumulates in the perinuclear region. Treatment of oligodendrocytes with the proteasomal inhibitor MG-132 (1 ,M; 18 h) caused an increase in the amount of TPPP/p25, by about 40%, a decrease in its solubility, and led to the appearance of TPPP/p25,-positive cytoplasmic inclusions, which stained with thioflavin S and resembled inclusion bodies. Hence, it might be speculated that acute or chronic malfunction of the proteasomal degradation system, leading to the accumulation of aggregation prone proteins and the pro-aggregatory protein TPPP/p25, or to the aggregation of TPPP/p25, on its own, is causally related to the protein aggregation process in a variety of neurodegenerative diseases. © 2008 Wiley-Liss, Inc. [source] Short Daily Dialysis (SDHD) Efficacy : Pilot Multicentric Study with Nine Patients from MadridHEMODIALYSIS INTERNATIONAL, Issue 1 2003G. Barril Interest in quotidian (daily) hemodialysis (HD) seems to be growing. Clinical data consistently showed improved quality of life, better control of blood pressure, less need for medications including erythropoietin (EPO) and better nutrition. We evaluate the SDHD efficacy in 9 patients in conventional HD (3 weekly sesions/4 hours), mean age 57,78 years range (33,75), 6 males and 3 females who needed increased dialysis efficiency by different medical indications: 5 cases with hypertensive miocardiopathy and severe LVH, 2 of them with EFLV 26% and 27%. 2 cases with ischemic cardiopathy symptoms, one of them with anger and restless dysnea with a non resvascularizable coronary lesion, and other with cardiac insufficiency episodes requiring hospitalization once a month. 1 patient with big body surface area and elevated phosphorus levels although without control, with conventional three times/week HD. 1 patient indication was made by 12 years on HD with multiple vascular accesses failed needing a Tessio cathéter being into infradialysis regimen for his malnutrition status. The schedule in all of them was 6 days per week sessions between 2.15 hrs till 3 hours depending of body surface area to obtain a weekly kt/v nearest to 4. HD session were realized in the Hospital (4 pts) or in satellite unit (5 pts) due to the characteristics of the patients. The time remaining in this schedule was between 5 months to 2 years and 9 months. All the patients showed clinical improvement, subjective and objective, since the first weeks of starting SDHD. Sleep symptoms were the first to improve. All patients showing good coping with this HD alternative. Blood pressure levels were controlled without need for antihypertensive drugs, although the dry weight increased significantly in all cases. Albumin serum levels increased as nutrition parameter, controlling also the osteodystrophy and phosphorus. In a patient the EFLV was normalized from 6 months (26%,50%) improving in other. Two patients could be included in Tx waiting list. Again, anemia improved and decreasing EPO was required. No vascular access (autologous AVF) malfunction was detected in relation to daily procedure. Conclusion: Our pilot experience shows a clinical and biochemical improvement in the patients and quality of life as well. Prospective studies to demonstrate the financial benefits of these modalities are needed. [source] Thermoeconomic analysis of a large industrial propane refrigeration cycle used in NGL recovery plantINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2009Mehdi Mehrpooya Abstract In this paper a propane refrigeration cycle has been analyzed by thermoeconomic approach. This cycle is used for obtaining required refrigeration in a natural gas liquids (NGL) recovery plant. Most of the advanced methods in thermoeconomic diagnosis are examined on power plants. In this work thermoeconomic diagnosis is applied to NGL recovery plant. The impact of the component inefficiencies on the fuel plant consumption, and the effect of a component inefficiency (intrinsic malfunction) on the rest of the plant components (induced malfunctions and dysfunctions), are analyzed and quantified. The results show that thermoeconomics is not only a diagnostic tool, but also a useful tool for optimization, which can be applied to complex refrigeration processes in NGL recovery plants. Copyright © 2009 John Wiley & Sons, Ltd. [source] Parent's involvement in decisions when their child is admitted to hospital with suspected shunt malfunction: study protocolJOURNAL OF ADVANCED NURSING, Issue 10 2009Joanna Smith Abstract Title., Parent's involvement in decisions when their child is admitted to hospital with suspected shunt malfunction: study protocol. Aim., This paper outlines the protocol for a study aimed at exploring parent's involvement during professional,parent interactions and decisions about their child's care in the context of suspected shunt malfunction. Background., Hydrocephalus is a long-term condition treated primarily by the insertion of a shunt that diverts fluid from the brain to another body compartment. Shunts frequently malfunction, and parents of children with shunted hydrocephalus are responsible for recognizing and responding to shunt complications. Parents feel that interactions with professionals when they seek healthcare advice for their child do always not encourage active participation in care decisions. Methods., The study design is based on qualitative methodologies: a combination of conversation analysis applied to consultation recordings of professional,parent interactions when a child is admitted to hospital with suspected shunt malfunction, and semi-structured follow-up interviews with the same participants within 2 weeks of the consultation. Participants., This is a prospective study and participants will be purposefully selected. Parents of children who have been admitted to hospital with suspected shunt malfunction and healthcare professionals responsible for the initial assessment of the child will be invited to participate. Discussion., The study will identify how decisions about a child's care are negotiated between parents and healthcare professionals at key stages of the care pathway. In addition, examining interactions between healthcare professionals and parents may identify approaches that support or hinder parents in contributing to the decision-making processes when they seek advice from healthcare professionals. [source] A Prospective Pediatric Clinical Trial of Digital Music Players: Do They Interfere with Pacemakers?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2009CHRISTINE C. CHIU M.Sc. Background: There has been recent concern in the media about iPodÔ interference with pacemakers. We systematically tested two types of digital music players (DMP) on pacemaker or ICD function in children. Methods/Results: Patients were monitored by a 6-lead ECG and programmer telemetry. The pacemaker was tested in bipolar and unipolar sensing at normal and maximal sensitivities. The order of DMP tested was randomized. Each DMP was placed on top of the pacemaker pocket, put into "play" mode three times (5 seconds each), with and without programmer wand placed one cm adjacent to DMP. Pacemaker interference was defined as: pacing inhibition, inappropriate pacing, oversensing, or detection of high-rate episodes associated with the use of DMP. Of the 67 patients (mean age 12 ± 5 years), 62 had pacemakers and five had ICDs; 39 endocardial and 28 epicardial systems. Patients were tested with SansaÔ (67), iPodÔ 30 GB (51), and other DMPs (43). There was no evidence of interference with pacemaker function by any DMP under any of the study conditions (each performed in triplicate). Reproducible programmer telemetry interference was shown in 11 cases (Medtronic 6/47, St. Jude Medical 5/18, Guidant 0/2) related to use of iPodÔ (6), SansaÔ (1), or others (4). None of these were associated with any evidence of pacemaker malfunction. Conclusion: Interference with pacemaker function could not be shown with iPodÔ or MP3 players. No additional precaution beyond standard is necessary for patients with pacemakers when they are using these players. [source] Analysis of Implantable Cardioverter Defibrillator Therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) TrialJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2003RICHARD C. KLEIN M.D. Introduction: The implantable cardioverter defibrillator (ICD) is commonly used to treat patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia recurrence rates in these patients are high, but which patients will receive a therapy and the forms of arrhythmia recurrence (VT or VF) are poorly understood. Methods and Results: The therapy delivered by the ICD was examined in 449 patients randomized to ICD therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. Events triggering ICD shocks or antitachycardia pacing (ATP) were reviewed for arrhythmia diagnosis, clinical symptoms, activity at the onset of the arrhythmia, and appropriateness and results of therapy. Both shock and ATP therapies were frequent by 2 years, with 68% of patients receiving some therapy or having an arrhythmic death. An appropriate shock was delivered in 53% of patients, and ATP was delivered in 68% of patients who had ATP activated. The first arrhythmia treated in follow-up was diagnosed as VT (63%), VF (13%), supraventricular tachycardia (18%), unknown arrhythmia (3%), or due to ICD malfunction or inappropriate sensing (3%). Acceleration of an arrhythmia by the ICD occurred in 8% of patients who received any therapy. No physical activity consistently preceded arrhythmias, nor did any single clinical factor predict the symptoms of the arrhythmia. Conclusion: Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided. (J Cardiovasc Electrophysiol, Vol. 14, pp. 940-948, September 2003) [source] Alteration and role of heat shock proteins in acute pancreatitisJOURNAL OF DIGESTIVE DISEASES, Issue 5 2010Jia Yan FENG Many etiological factors are involved in the pathogenesis of acute pancreatitis. The pathogenesis of acute pancreatitis has been attributed to such causes as trypsin autodigestion, pancreatic microcirculation malfunction, the calcium overload in pancreatic acinar cells, oxygen free radical injury, cytokine injury, and has been treated in detail in numerous reviews. More recently, heat shock proteins (HSP), particularly heat shock protein 60 (HSP60), have receive increasing attention as another possible factor in the pathogenesis and development of acute pancreatitis. This brief review aims to: (i) outline our current understanding of HSP and their role in pancreatitis; (ii) discuss the available evidences that suggest HSP's interplay between pancreas tissues and etiological agents; (iii) delineate the functional mechanisms of HSP proposed by different research groups, and offer new thinking in preventing and treating acute pancreatitis in general. [source] Trauma: physiology, pathophysiology, and clinical implicationsJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2006DACVA, DACVECC, William Muir DVM Abstract Objective: To review the physiology, pathophysiology, and consequences of trauma. The therapeutic implications of hypovolemia, hypotension, hypothermia, tissue blood flow, oxygen delivery, and pain will be discussed. Data Sources: Human and veterinary clinical and research studies. Human and veterinary data synthesis: Trauma is defined as tissue injury that occurs more or less suddenly as a result of violence or accident and is responsible for initiating hyothalamic,pituitary,adrenal axis, immunologic and metabolic responses that are designed to restore homeostasis. Tissue injury, hemorrhage, pain, and fear are key components of any traumatic event. Trauma and blood loss result in centrally integrated autonomic-mediated cardiovascular responses that are designed to increase heart rate, systemic vascular resistance, and maintain arterial blood pressure (ABP) to vital organs at the expense of blood flow to the gut and skeletal muscle. Severe trauma elicits exuberant physiologic, immunologic, and metabolic changes predisposing the animal to organ malfunction, a systemic inflammatory response, infection, and multiple organ dysfunctions. The combination of both central and local influences produces regional redistribution of blood flow among and within tissue beds which, when combined with impaired vascular reactivity, leads to maldistribution of blood flow to tissues predisposing to tissue hypoperfusion and impaired oxygen delivery and extraction. Gut blood flow and viability may serve as a sentinel of patient survival. These consequences are magnified in animals suffering from pain or that become hypothermic. Successful treatment of traumatized animals goes beyond the restoration of blood pressure and urine output, is dependent on a fundamental understanding of the pathophysiologic processes responsible for the animals current physical status, and incorporates the reduction of pain, stress, and the systemic inflammatory response and methods that restore microcirculatory blood flow and tissue oxygenation. Conclusions: Severe trauma is a multifaceted event and is exacerbated by hypothermia, pain, and stress. Therapeutic approaches must go beyond the simple restoration of vascular volume and ABP by maintaining tissue blood flow, restoring tissue oxygenation, and preventing systemic inflammation. [source] Prevention and treatment of rethrombosis after liver transplantation with an implantable pump of the portal veinLIVER TRANSPLANTATION, Issue 3 2010Zhengrong Shi Implantable pumps have been used to prevent deep vein thrombosis and other diseases. In this article, we report for the first time the prevention and treatment of rethrombosis of the portal vein in liver transplantation with an implantable pump of the portal vein. Four hundred four orthotopic liver transplantation cases were retrospectively reviewed and divided into 3 groups: portal vein thrombosis (PVT) patients with an implantable pump (n = 28), PVT patients without an implantable pump (n = 20), and patients without preexisting PVT (n = 356). The following parameters for the 3 groups of patients were calculated and compared: (1) preoperative parameters, including baseline data of the donors and recipients and times of graft ischemia; (2) intraoperative and postoperative parameters, including surgery time, red blood cell and plasma transfusion, platelet concentrate transfusion, bleeding and primary graft malfunction, and duration of the hospital and intensive care unit stays; and (3) follow-up information for the patency of the portal vein, rethrombosis rate, stenosis and reoperation (relaparotomy or retransplantation), in-hospital mortality, and actuarial 1-year survival rate. Among the 3 groups of recipients, no significant differences were detected in preoperative and intraoperative parameters. However, compared to PVT patients without an implantable pump, PVT patients with an implantable pump showed remarkable reductions in their postoperative hospital stay, rethrombosis, reoperation rate, and in-hospital mortality. An implantable pump of the portal vein in liver transplantation patients can prevent and facilitate the treatment of portal vein rethrombosis and is associated with a reduction of in-hospital mortality. Liver Transpl 16:324,331, 2010. © 2010 AASLD. [source] Sacral nerve stimulation for voiding dysfunction: One institution's 11-year experience,NEUROUROLOGY AND URODYNAMICS, Issue 1 2007Suzette E. Sutherland Abstract Aim The purpose of this study was to review our institution's 11-year experience with SNS for the treatment of refractory voiding dysfunction. Dating back to 1993, it covers a span of time which describes the evolution of SNS as it includes PNE trials, non-tined (bone-anchored or fascial-anchored) leads, percutaneous tined leads with two-staged procedures, and even percutaneous pudendal trials. Methods A retrospective review was performed on SNS patients who received an implantable pulse generator (IPG) in our practice from 12/1993 to 12/2004. After Institutional Review Board approval, consents for chart review were obtained from 104 patients, representing 44% of this neuromodulatory patient population. Results Of our population, 87% were female and 13% were male. Average age at implant was 50 years,±,13.4 years. Duration of symptoms before implantation was 116 months (range 9,600 months). Eighty percent were implanted for a predominant complaint of urinary urgency and frequency (U/F). Overall, 22% had U/F only, 38% had concomitant urge incontinence (UI), and 20% had concomitant mixed incontinence (MI). Twenty percent were treated for non-obstructive urinary retention (UR), with half of these associated with a neurogenic etiology. Additionally, 46.2% had pelvic pain, 58.6% had bowel complaints, and 51% reported sexual dysfunction. In patients with U/F, mean voiding parameters as described by pre-implant voiding diaries revealed the following: 12.4 (±5.1) voids per 24 hr; 2.3 (±1.8) voids per night; 5.0 (±4.7) leaks per 24 hr; and 2.3 (±2.6) pads per 24 hr. Statistically significant improvements post-implantation were noted with mean decreases in the following: 4.3 voids per 24 hr; 1.0 void per night; 4.4 leaks per 24 hr; and 2.3 pads per 24 hr (all P,<,0.05). In the UR group a statistically significant improvement post-implantation was noted only in voids per night, with a mean decrease of 0.8 (P,<,0.05). With a mean follow up of 22 months (range 3,162 months), sustained subjective improvement was >50%, >80%, and >90% in 69%, 50%, and 35% of patients, respectively. By quality of life survey, 60.5% of patients were satisfied and 16.1% were dissatisfied with current urinary symptoms. Only 13% (14 patients) abandoned therapy, making up a significant portion of those dissatisfied with current urinary symptoms. Good overall lead durability was seen (mean 22 months, range 1,121 months), with the first successful lead proving to be the most durable (mean 28 months, range 1.4,120 months). Lead durability decreased progressively with subsequent trials. Overall, 53% of patients experienced at least one reportable event (RE) attributable to either lead or IPG. A total of 126 REs were noted, with 97% mild-to-moderate in severity. REs included lack of efficacy, loss of efficacy, infection, hematoma/seroma, migration, pain, undesirable change in sensation, and device malfunction. In this population, 47.1% of leads were tined while 52.9% were non-tined. Tined leads had an overall lower RE rate as compared to non-tined leads: 28% and 73%, respectively. Conclusions SNS is an effective method for treating certain types of voiding dysfunction. Although 53% of patients experienced at least one RE, 97% were mild-to-moderate and did not appear to affect the continued use of this therapy. With improved technology, such as percutaneous tined leads, the RE rate is decreasing. Further analyses of subsets of this population are currently underway. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source] On fusion of PCA and a physical model-based predictive control strategy for efficient load-cycling operation of a thermal power plantOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 4 2007Girijesh Prasad Abstract Controlling a thermal power plant optimally during load-cycling operation is a very challenging control problem. The control complexity is enhanced further by the possibility of simultaneous occurrence of sensor malfunctions and a plethora of system disturbances. This paper proposes and evaluates the effectiveness of a sensor validation and reconstruction approach using principal component analysis (PCA) in conjunction with a physical plant model. For optimal control under severe operating conditions in the presence of possible sensor malfunctions, a predictive control strategy is devised by appropriate fusion of the PCA-based sensor validation and reconstruction approach and a constrained model predictive control (MPC) technique. As a case study, the control strategy is applied for thermal power plant control in the presence of a single sensor malfunction. In particular, it is applied to investigate the effectiveness and relative advantage of applying rate constraints on main steam temperature and heat-exchanger tube-wall temperature, so that faster load cycling operation is achieved without causing excessive thermal stresses in heat-exchanger tubes. In order to account for unstable and non-minimum phase boiler,turbine dynamics, the MPC technique applied is an infinite horizon non-linear physical model-based state-space MPC strategy, which guarantees asymptotic stability and feasibility in the presence of output and state constraints. Copyright © 2007 John Wiley & Sons, Ltd. [source] Pacemaker and Defibrillator Lead Extraction: Predictors of Mortality during Follow-UpPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2010SHOAIB HAMID M.D. Background:Extraction of cardiac implantable electric devices is an accepted procedure when systems become infected or malfunction. However, there is an associated morbidity and mortality. We report our 5-year experience and identify predictors of mortality, and long-term follow-up. Methods:We analyzed extraction data from January 2003 to November 2007. Extraction methods used were: locking stylets, telescoping sheaths ± laser, and femoral work stations. Results:One hundred and eighty-three cases were referred, aged 65 ± 16 years (range 28,83); 76% were males. Mean implant time was 75 months (range 4,312 months) and indications were: pocket infection (48%), nonfunctioning lead (22%), erosion through skin (18%), endocarditis/septicemia (11%), bilateral superior vena cava thrombosis (0.5%), and painful lead (0.5%). The number of leads extracted were 369, with complete removal in 90.7% and partial in 7.6%. There were no intraoperative deaths but five (2.7%) died within the same admission as their extraction from overwhelming sepsis. Twelve deaths (6.6%) occurred during an average follow-up of 965 days (range 40,1670). Multivariate logistic regression demonstrated that C-reactive protein preprocedure was predictive of acute in-hospital mortality. Conclusions:Intravascular lead extraction is a safe and efficient method of removing leads. However, there is a subgroup of patients with systemic sepsis with raised inflammatory markers who are at high risk of in-hospital mortality. Long-term follow-up demonstrates mortality which is a marker of the underlying etiology for device implantation, with heart failure patients particularly at risk. (PACE 2010; 33:209,216) [source] Clinical Judgment Versus Decision Analysis for Managing Device AdvisoriesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2008MITESH S. AMIN M.D. Introduction: Implantable cardioverter-defibrillator (ICD) and pacemaker (PM) advisories may have a significant impact on patient management. Surveys of clinical practice have shown a great deal of variability in patient management after a device advisory. We compared our management of consecutive patients in a single large university practice with device advisories to the "best" patient management strategy predicted by a decision analysis model. Methods: We performed a retrospective review of all patients who had implanted devices affected by an advisory at our medical center between March 2005 and May 2006 and compared our actual patient management strategy with that subsequently predicted by a decision analysis model. Results: Over 14 months, 11 advisories from three different manufacturers affected 436 patients. Twelve patients (2.8%) were deceased and 39 patients (8.9%) were followed at outside facilities. Management of the 385 remaining patients varied based on type of malfunction or potential malfunction, manufacturer recommendations, device dependency, and patient or physician preferences. Management consisted of the following: 57 device replacements (15.2%), 44 devices reprogrammed or magnets issued (11.7%), and 268 patients underwent more frequent follow-up (71.3%). No major complications, related to device malfunction or device replacement, occurred among any patient affected with a device advisory. Concordance between the decision analysis model and our management strategy occurred in 57.1% of cases and 25 devices were replaced when it was not the preferred treatment strategy predicted by the decision model (43.9%, 37.3% when excluding devices replaced based on patient preference). The decision analysis favored replacement for all patients with PM dependency, but only for four patients with ICDs for secondary prevention. No devices were left implanted that the decision analysis model predicted should have been replaced. Conclusions: We found that despite a fairly conservative device replacement strategy for advisories, we still replaced more devices when it was not the preferred device management strategy predicted by a decision analysis model. This study demonstrates that even when risks and benefits are being considered by experienced clinicians, a formal decision analysis can help to develop a systematic evidence based approach and potentially avoid unnecessary procedures. [source] Effects of Scatter Radiation on ICD and CRT FunctionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2008SURAJ KAPA M.D. Background: Effects of direct radiation on implantable cardiac devices have been well studied. However, the effects of scatter radiation are not as clear. Recommendations on management of patients with implantable cardiac devices undergoing radiotherapy are based on limited studies mostly involving pacemakers. We sought to elucidate the effects of scatter radiation on implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT)-ICDs. Methods: We exposed 12 ICDs and eight CRT-ICDs to 400 cGy of scatter radiation from a 6-MV photon beam. Devices were programmed with nominal parameters and interrogated prior to radiation, after each fraction, upon completion of the radiation course and again 1 week later. A retrospective review of patients undergoing radiotherapy at the Mayo Clinic,Rochester between 2002 and 2007 in whom the device was outside the radiation field was also performed. There were 13 patients with devices undergoing radiotherapy during this time period, 12 of whom were interrogated prior to and after radiation. Results: Interrogation reports were reviewed for device reset or parameter changes. There was no evidence of reset or malfunction during or after radiation. Also, no episodes of device reset, inappropriate sensing or therapy, or changes in programmed parameters were found in our review of patients undergoing radiotherapy. Conclusions: Device reset or malfunction associated with scatter radiation likely represents an unpredictable, rare occurrence. While we see no clear contraindication to radiotherapy in patients with ICDs or CRT-ICDs, precautions should be taken to avoid direct radiation exposure and to closely evaluate patient outcomes before and after the radiation course. [source] Feasibility Of Temporary Biventricular Pacing In Patients With Reduced Left Ventricular Function After Coronary Artery Bypass GraftingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007FRANK EBERHARDT M.D. Background and Methods: Biventricular pacing improves hemodynamics after weaning from cardiopulmonary bypass in patients with severely reduced left ventricular (LV) function undergoing coronary artery bypass grafting (CABG). We examined the feasibility of temporary biventricular pacing for 96 hours postoperatively. Unipolar epicardial wires were placed on the roof of the right atrium (RA), the right ventricular (RV) outflow tract, and the LV free lateral wall and connected to an external pacing device in 51 patients (mean LV ejection fraction 35 ± 4%). Pacing and sensing thresholds, lead survival and incidence of pacemaker dysfunction were determined. Results: Atrial and RV pacing thresholds increased significantly by the 4th postoperative day, from 1.6 ± 0.2 to 2.5 ± 0.3 V at 0.5 ms (P = 0.03) at the RA, 1.4 ± 0.3 V to 2.7 ± 0.4 mV (P = 0.01) at the RV, and 1.9 ± 0.6 V to 2.9 ± 0.7 mV (P = 0.3) at the LV, while sensing thresholds decreased from 2.0 ± 0.2 to 1.7 ± 0.2 mV (P = 0.18) at the RA, 7.2 ± 0.8 to 5.1 ± 0.7 mV (P = 0.05) at the RV, and 9.4 ± 1.3 to 5.5 ± 1.1 mV (P = 0.02) at the LV. The cumulative overall incidence of lead failure was 24% by the 4th postoperative day, and was similar at the RV and LV. We observed no ventricular proarrhythmia due to pacing or temporary pacemaker malfunction. Conclusions: Biventricular pacing after CABG using a standard external pacing system was feasible and safe. [source] A Coroner's Request for Closure: The Value of the Stored ElectrogramPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2006IRENE H. STEVENSON Pacemaker diagnostics can be useful to troubleshoot both during life and after death. A 58-year old man with a single chamber ventricular pacemaker and a previous His bundle ablation died suddenly. Interrogation of his pacemaker revealed the cause of death not as pacemaker malfunction, but a fatal ventricular arrhythmia. [source] Venous Occlusion of the Access Vein in Patients Referred for Lead Extraction:PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2003Influence of Patient, Lead Characteristics The aim of this study was to determine the effect of patient and lead characteristics on occlusion of the access vein in pacemaker and ICD patients. Contrast venography of the access vein was obtained in 89 patients (17 patients with an ICD) scheduled for lead extraction. The indication for extraction was infection in 57 patients (systemic infection in 9) and lead malfunction in 32 patients. In 6 of the 89 patients, leads were introduced in both the right and left subpectoral area, resulting in a total of 95 venous entry sites. In 22 of these entry sites one lead was present, in 61 two leads, in 11 three, and in 1 four leads. The vessel patency was graded open or occluded. Occlusion of the subclavian vein occurred in four (13%) patients with lead malfunction versus 18 (32%) patients with infection (P = 0.07). In patients with systemic infection, 5 of 9 showed venous occlusion (P = 0.01 when compared to patients with malfunction, odds ratio 8.75, 95% confidence interval 1.21,64.11). Considered per entry site, the incidence of occlusion was 7 of 22 with one lead present, 17 of 61 with two leads, 0 of 11 with three leads, and 0 of 1 with four leads (P = 0.13). No patient had a superior vena caval occlusion. Patients with systemic infection have an increased risk of occlusion of the access vein. On the contrary, the study found no support for the concept that the risk of venous occlusion increases with a higher number of leads present. (PACE 2003; 26:1649,1652) [source] | ||||||||||||||||||||||||||||||||||||||||||||||