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Assistive Devices and Clothing: Exploring Adaptive Clothing Needs for Women with Lower Limb Prostheses Using the FEA Model
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作者 Mastourah Al Asmari Mirahan Farag Zedan 《Open Journal of Applied Sciences》 2024年第10期2901-2922,共22页
This study aimed to comprehensively investigate the essential considerations in designing adaptive clothing for women with lower limb prostheses in Saudi Arabia. Employing a qualitative methodology, the research entai... This study aimed to comprehensively investigate the essential considerations in designing adaptive clothing for women with lower limb prostheses in Saudi Arabia. Employing a qualitative methodology, the research entailed semi-structured, in-depth interviews with women utilizing lower limb prostheses and prosthetic specialists. This approach was selected to unearth pivotal design prerequisites and comprehend the specific challenges these women encounter within the realm of clothing. The utilization of selective sampling facilitated the collection of intricate and valuable insights. A Functional, Expressive, and Aesthetic (FEA) User Needs model was utilized to scrutinize participant feedback. Functional requisites encompass ease of dressing and undressing, accessibility to the prosthetic limb, comfort, mobility with the prosthesis, and appropriate fit. Additionally, participants highlighted various expressive needs, including privacy preservation, modesty, camouflaging disability appearances, maintaining alignment with non-disabled women’s fashion, and considerations about the aesthetic aspects of garments. 展开更多
关键词 assistive devices Adaptive Clothing Lower Limb Prosthetics Functional Expressive and Aesthetic (FEA) Model
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Resilience-Oriented Approach to the Control of Ventricular Assist Devices
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作者 Jônatas Cerqueira Dias Jeferson Cerqueira Dias +1 位作者 Milena Victoria de Azevedo Souza Diolino José dos Santos Filho 《Journal of Biomedical Science and Engineering》 2024年第8期137-156,共20页
Context: Advanced heart failure (AHF) poses a global challenge, where heart transplantation is a treatment option but limited by donor scarcity. Proposal: This study aims to enhance the performance of ventricular assi... Context: Advanced heart failure (AHF) poses a global challenge, where heart transplantation is a treatment option but limited by donor scarcity. Proposal: This study aims to enhance the performance of ventricular assist devices (VADs) in the face of adverse events (AEs) using a resilience-based approach. The objective is to develop a method for integrating resilience attributes into VAD control systems, employing dynamic risk analysis and control strategies. Results: The outcomes include a resilient control architecture enabling anticipatory, regenerative, and degenerative actions in response to AEs. A method of applied resilience (MAR) based on dynamic risk management and resilience attribute analysis was proposed. Conclusion: Dynamic integration between medical and technical teams allows continuous adaptation of control systems to meet patient needs over time, improving reliability, safety, and effectiveness of VADs, with potential positive impact on the health of heart failure patients. 展开更多
关键词 Heart Failure Ventricular Assist devices RESILIENCE Dynamic Control
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Treatment of gastrointestinal bleeding in left ventricular assist devices:A comprehensive review 被引量:2
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作者 Srikanth Vedachalam Gokulakrishnan Balasubramanian +1 位作者 Garrie J Haas Somashekar G Krishna 《World Journal of Gastroenterology》 SCIE CAS 2020年第20期2550-2558,共9页
Left ventricular assist devices(LVAD)are increasingly become common as life prolonging therapy in patients with advanced heart failure.Current devices are now used as definitive treatment in some patients given the im... Left ventricular assist devices(LVAD)are increasingly become common as life prolonging therapy in patients with advanced heart failure.Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps.Unfortunately,continuous flow LVADs are fraught with complications such as gastrointestinal(GI)bleeding that are primarily attributed to the formation of arteriovenous malformations.With frequent GI bleeding,antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events.Small bowel bleeds account for 15%as the source and patients often undergo multiple endoscopic procedures.Treatment strategies include resuscitative measures and endoscopic therapies.Medical treatment is with octreotide.Novel treatment options include thalidomide,angiotensin converting enzyme inhibitors/angiotensinⅡreceptor blockers,estrogen-based hormonal therapies,doxycycline,desmopressin and bevacizumab.Current research has explored the mechanism of frequent GI bleeds in this population,including destruction of von Willebrand factor,upregulation of tissue factor,vascular endothelial growth factor,tumor necrosis factor-α,tumor growth factor-β,and angiopoetin-2,and downregulation of angiopoetin-1.In addition,healthcare resource utilization is only increasing in this patient population with higher admissions,readmissions,blood product utilization,and endoscopy.While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages,these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years. 展开更多
关键词 Left ventricular assist device Push enteroscopy Double balloon enteroscopy Video capsule endoscopy OCTREOTIDE BEVACIZUMAB Gastrointestinal bleeding
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Comprehensive review of hemolysis in ventricular assist devices 被引量:1
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作者 Christos A Papanastasiou Konstantinos G Kyriakoulis +3 位作者 Christina A Theochari Damianos G Kokkinidis Theodoros D Karamitsos Leonidas Palaiodimos 《World Journal of Cardiology》 CAS 2020年第7期334-341,共8页
Ventricular assist devices(VADs)have played an important role in altering the natural history of end-stage heart failure.Low-grade hemolysis has been traditionally described in patients with VADs,indicating effective ... Ventricular assist devices(VADs)have played an important role in altering the natural history of end-stage heart failure.Low-grade hemolysis has been traditionally described in patients with VADs,indicating effective device functionality.However,clinically significant hemolysis could be crucial in terms of prognosis,calling for prompt therapeutic actions.The absence of solid and widely approved diagnostic criteria for clinically significant hemolysis,render the utilization of hemolysis laboratory markers challenging.Hemolysis incidence varies(5%-18%)depending on definition and among different VAD generations,being slightly higher in continuous-flow devices than in pulsatile devices.Increased shear stress of red blood cells and underlying device thrombosis appear to be the main pathogenetic pathways.No certain algorithm is available for the management of hemolysis in patients with VADs,while close clinical and laboratory monitoring remains the cornerstone of management.Imaging examinations such as echocardiography ramp test or computed tomography scan could play a role in revealing the underlying cause.Treatment should be strictly personalized,including either pharmacological(antithrombotic treatment)or surgical interventions. 展开更多
关键词 Ventricular assist device HEMOLYSIS THROMBOSIS
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Utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist devices
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作者 Ajay K Bhatia Mouhammad Yabrodi +4 位作者 Mallory Carroll Silvia Bunting Kirk Kanter Kevin O Maher Shriprasad R Deshpande 《World Journal of Cardiology》 CAS 2017年第9期749-756,共8页
AIM To assess utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist device(VAD). METHODS Retrospective study of pediatric patients supported with a Berlin EXCOR ... AIM To assess utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist device(VAD). METHODS Retrospective study of pediatric patients supported with a Berlin EXCOR VAD at a single pediatric tertiary care center during a single year.RESULTS We demonstrated associations between activated thro-mboplastin time(a PTT) and R-thromboelastography(R-TEG) values(rs = 0.65, P < 0.001) and between anti-Xa assay and R-TEG values(rs = 0.54, P < 0.001). The strongest correlation was seen between a PTT and anti-Xa assays(rs = 0.71, P < 0.001). There was also a statistically significant correlation between platelet counts and the maximum amplitude of TEG(rs = 0.71, P < 0.001). Importantly, there was no association between dose of unfractionated heparin and either measure of anticoagulation(a PTT, anti-Xa or R-TEG value). CONCLUSION This study suggests that while there is strong correlation between a PTT, anti-Xa assay and R-TEG values for patients requiring VAD support, there is a lack of relevant correlation between heparin dose and degree of effect. This raises concern as various guidelines continue to recommend using these parameters to titrate heparin therapy. 展开更多
关键词 Ventricular assist device ANTICOAGULATION BERLIN--EXCOR PEDIATRIC THROMBOELASTOGRAPHY
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Effects of medically generated electromagnetic interference from medical devices on cardiac implantable electronic devices: A review
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作者 Walker Barmore Himax Patel +2 位作者 Cassandra Voong Caroline Tarallo Joe B Calkins Jr 《World Journal of Cardiology》 2022年第8期446-453,共8页
As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and pr... As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference. 展开更多
关键词 Electromagnetic interference Pacemaker Implantable cardioverter defibrillator Permanent pacemakers Cardiac implantable electronic devices Left ventricular assist device Endoscopy BRONCHOSCOPY ELECTROCAUTERY Capsule endoscopy Transcutaneous electrical nerve stimulators unit Spinal cord stimulator
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To ventricular assist devices or not:When is implantation of a ventricular assist device appropriate in advanced ambulatory heart failure?
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作者 Emily Cerier Brent C Lampert +3 位作者 Arman Kilic Asia McDavid Salil V Deo Ahmet Kilic 《World Journal of Cardiology》 CAS 2016年第12期695-702,共8页
Advanced heart failure has been traditionally treated via either heart transplantation,continuous inotropes,consideration for hospice and more recently via left ventricular assist devices(LVAD).Heart transplantation h... Advanced heart failure has been traditionally treated via either heart transplantation,continuous inotropes,consideration for hospice and more recently via left ventricular assist devices(LVAD).Heart transplantation has been limited by organ availability and the futility of other options has thrust LVAD therapy into the mainstream of therapy for end stage heart failure.Improvements in technology and survival combined with improvements in the quality of life have made LVADs a viable option for many patients suffering from heart failure.The question of when to implant these devices in those patients with advanced,yet still ambulatory heart failure remains a controversial topic.We discuss the current state of LVAD therapy and the risk vs benefit of these devices in the treatment of heart failure. 展开更多
关键词 Left ventricular assist device Mechanical circulatory support Heart failure CARDIOMYOPATHY Diastolic dysfunction
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Heart and Lung Mechanical Assist Devices are Comprehensively Tested by the New Hybrid Simulators
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作者 M.Darowski K.J.Palko +5 位作者 M.Kozarski K.Zielinski K.Gorczynska G.Ferrari L.Fresiello A.Di Molfetta 《Engineering(科研)》 2012年第10期124-125,共2页
Two applications of the hybrid simulators have been presented as examples: nonpulsatile VAD interaction with lumped parameters cardiovascular system numerical model and respirator interacting with the Dubois numerical... Two applications of the hybrid simulators have been presented as examples: nonpulsatile VAD interaction with lumped parameters cardiovascular system numerical model and respirator interacting with the Dubois numerical model of obstructive lung diseases. The results of simulations showed how the tested assist devices change biological system - assist device characteristics in the course of heart or lungs diseases and how it influences pressure and flow in a particular point of cardiovascular or respiratory system numerical model. 展开更多
关键词 Ventricular Assist Device RESPIRATOR MODELLING Hybrid Simulator
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Combined Application of Circulatory Assist Devices Following Cardiac Arrest in Patients after Cardiac Surgery
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作者 黄焕雷 肖学钧 +4 位作者 吴若彬 范瑞新 成安衡 章晓华 罗征祥 《South China Journal of Cardiology》 CAS 2006年第1期47-52,共6页
Objectives To evaluate retrospectively the potential benefits of combined utilization of various assisted circulation devices in cardiac arrest patients who did not respond to conventional cardiopulmonary cerebral res... Objectives To evaluate retrospectively the potential benefits of combined utilization of various assisted circulation devices in cardiac arrest patients who did not respond to conventional cardiopulmonary cerebral resuscitation (CPCR). Methods Assisted circulation devices, including emergency cardiopulmonary bypass (ECPB), intra-aortic balloon pump (IABP), and left ventricular assist device (LVAD), were applied to 16 adult patients who had cardiac arrest 82 rain-56 h after open heart surgery and did not respond to 20 rain or longer conventional CPCR. ECPB was applied to 2 patients, ECPB plus IABP to 8 patients, ECPB plus IABP and LVAD to 6 patients. Results One patient recovered fully and one patient died. Of the other 14 patients, 13 resumed spontaneous cardiac rhythm and one did not; none of them could be weaned from ECPB. Further treatment of the 14 patients with combinations of assisted circulation devices enabled 6 patients to recover. One of the 7 recovered patients died of reoccurring cardiac arrest after 11 days; the other 6 were discharged in good condition and were followed up for 3-49 months (mean =22 months). Of the 6 discharged patients one suffered cerebral embolism during LVAD treatment, resulting in mild limitation of mobility of the right limbs ; the other 5 never manifested any central nervous system complications. There was no late deaths giving a 37.5% (6/16) long-term survival rate. Conclusions ECPB could effectively reestablish blood circulation and oxygen supply, rectify acidosis, and improve internal milieu. The combined utilization of ECPB, IABP, and LVAD reduces the duration of ECPB, improves the incidence of recovery, and offers beneficial alternatives to refractory cardiac arrest patients. 展开更多
关键词 Cardiopulmonary cerebral resuscitation Cardiopulmonary bypass Left ventricular assist device Intra-aortic balloon pumping
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Bleeding with the artificial heart: Gastrointestinal hemorrhage in CF-LVAD patients 被引量:6
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作者 Grigoriy E Gurvits Elena Fradkov 《World Journal of Gastroenterology》 SCIE CAS 2017年第22期3945-3953,共9页
Continuous-flow left ventricular assist devices(CF-LVADs)have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or,more recently,as destination ... Continuous-flow left ventricular assist devices(CF-LVADs)have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or,more recently,as destination therapy.However,its implantations carries a risk of complications including infection,device malfunction,arrhythmias,right ventricular failure,thromboembolic disease,postoperative and nonsurgical bleeding.A significant number of left ventricular assist devices(LVAD)recipients may experience recurrent gastrointestinal hemorrhage,mainly due to combination of antiplatelet and vitamin K antagonist therapy,activation of fibrinolytic pathway,acquired von Willebrand factor deficiency,and tendency to develop small intestinal angiodysplasias due to increased rotary speed of the pump.Gastrointestinal bleeding in LVAD patients remains a source of increased morbidity including the need for blood transfusions,extended hospital stays,multiple readmissions,and overall mortality.Management of gastrointestinal bleeding in LVAD patients involves multidisciplinary approach in stabilizing the patients,addressing risk factors and performing structured endoluminal evaluation with focus on upper gastrointestinal tract including jejunum to find and eradicate culprit lesion.Medical and procedural intervention is largely successful and universal bleeding cessation occurs in transplanted patients. 展开更多
关键词 Gastrointestinal bleeding Left ventricular assist devices Heart failure Angioectasia ENDOSCOPY
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Emerging concepts in alcoholic hepatitis 被引量:4
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作者 Phoenix Fung Nikolaos Pyrsopoulos 《World Journal of Hepatology》 CAS 2017年第12期567-585,共19页
Severe alcoholic hepatitis is implicated as a costly,worldwide public health issue with high morbidity and mortality. The one-month survival for severe alcoholic hepatitis is low with mortality rates high as 30%-50%. ... Severe alcoholic hepatitis is implicated as a costly,worldwide public health issue with high morbidity and mortality. The one-month survival for severe alcoholic hepatitis is low with mortality rates high as 30%-50%. Abstinence from alcohol is the recommended firstline treatment. Although corticosteroids remain as the current evidence based option for selected patients with discriminant function > 32, improvement of short-term survival rate may be the only benefit. Identification of individuals with risk factors for the development of severe alcoholic hepatitis may provide insight to the diverse clinical spectrum and prognosis of the disease. The understanding of the complex pathophysiologic processes of alcoholic hepatitis is the key to elucidating new therapeutic treatments. Newer research describes the use of gut microbiota modification, immune modulation, stimulation of liver regeneration, caspase inhibitors, farnesoid X receptors, and the extracorporeal liver assist device to aid in hepatocellular recovery. Liver transplantation can be considered as the last medical option for patients failing conventional medical interventions. Although the preliminary data is promising in patients with low risk of recividism, controversy remains due to organ scarcity. This review article comprehensively summarizes the epidemiology, pathophysiology, risk factors, and prognostic indicators of severe alcoholic hepatitis with a focus on the current and emerging therapeutics. 展开更多
关键词 Immune modulation Alcoholic hepatitis Gut microbiota modification Extracorporeal liver assist device Apoptosis inhibitors
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Ambulatory pulmonary artery pressure monitoring in advanced heart failure patients 被引量:1
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作者 Srikanth Yandrapalli Anoshia Raza +1 位作者 Sohaib Tariq Wilbert S Aronow 《World Journal of Cardiology》 CAS 2017年第1期21-26,共6页
Heart failure (HF) is an emerging epidemic associate with significant morbidity, mortality, and health care expenditure. Although there were major advances in pharmacologic and device based therapies for the managemen... Heart failure (HF) is an emerging epidemic associate with significant morbidity, mortality, and health care expenditure. Although there were major advances in pharmacologic and device based therapies for the management of HF, mortality of this condition remains high. Accurate monitoring of HF patients for exacerbations is very important to reduce recurrent hospitalizations and its associated complications. With the failure of clinical signs, tele-monitoring, and laboratory bio-markers to function as early markers of HF exacerbations, more sophisticated techniques were sought to accurately predict the circulatory status in HF patients in order to execute timely pharmacological intervention to reduce frequent hospitalizations. CardioMEMS<sup>TM</sup> (St. Jude Medical, Inc., Saint Paul, Minnesota) is an implantable, wireless pulmonary arterial pressure (PAP) monitoring system which transmits the patient’s continuous PAPs to the treating health care provider in the ambulatory setting. PAP-guided medical therapy modification has been shown to significantly reduce HF-related hospitalization and overall mortality. In advanced stages of HF, wireless access to hemodynamic information correlated with earlier left ventricular assist device implantation and shorter time to heart transplantation. 展开更多
关键词 CardioMEMS Heart failure Remote heart failure monitoring Pulmonary arterial pressure monitoring Left ventricular assist device
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Enteroscopy in children and adults with inflammatory bowel disease 被引量:2
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作者 Giovanni Di Nardo Gianluca Esposito +7 位作者 Chiara Ziparo Federica Micheli Luigi Masoni Maria Pia Villa PasqualeParisi Maria Beatrice Manca Flavia Baccini Vito Domenico Corleto 《World Journal of Gastroenterology》 SCIE CAS 2020年第39期5944-5958,共15页
Inflammatory bowel disease(IBD)includes Crohn’s disease(CD),ulcerative colitis and unclassified entities.CD commonly involves the terminal ileum and colon but at the time of diagnosis it can be confined to the small ... Inflammatory bowel disease(IBD)includes Crohn’s disease(CD),ulcerative colitis and unclassified entities.CD commonly involves the terminal ileum and colon but at the time of diagnosis it can be confined to the small bowel(SB)in about 30%of the patients,especially in the young ones.Management of isolated SB-CD can be challenging and objective evaluation of the SB mucosa is essential in differentiating CD from other enteropathies to achieve therapeutic decisions and to plan the follow-up.The introduction of cross-sectional imaging techniques and capsule endoscopy(CE)have significantly expanded the ability to diagnose SB diseases providing a non-invasive test for the visualization of the entire SB mucosa.The main CE limitations are the low specificity,the lack of therapeutic capabilities and the impossibility to take biopsies.Device assisted enteroscopy(DAE)enables histological confirmation when traditional endoscopy,capsule endoscopy and cross-sectional imaging are inconclusive and also allows therapeutic interventions such as balloon stricture dilation,intralesional steroid injection,capsule retrieval and more recently stent insertion.In the current review we will discuss technical aspect,indications and safety profile of DAE in children and adults with IBD. 展开更多
关键词 ENTEROSCOPY Device assisted enteroscopy Inflammatory bowel disease Crohn’s disease Small bowel disease Endoscopic balloon dilation
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Evolvement of left ventricular assist device: the implications on heart failure management 被引量:1
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作者 Sek Ying Chair Doris SF Yu +4 位作者 Michael Timothy Ng Qun Wang Ho Yu Cheng Eliza ML Wong Janet WH Sit 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第5期425-430,共6页
Heart failure (HF) is a potentially fatal disease that affects increasing number of people worldwide. Although heart transplant is the "gold standard" therapy for HF, due to the limited availability of organs, man... Heart failure (HF) is a potentially fatal disease that affects increasing number of people worldwide. Although heart transplant is the "gold standard" therapy for HF, due to the limited availability of organs, many patients died when waiting for the transplant. Left ventricular assist device (LVAD), as a mechanical circulatory support, has become a new light for patients with HF. With the technical advancements, LVADs work not only as a bridge to transplant, but also assist heart recovery and even as a destination therapy in long-term treatment. This observation paper reviewed the development of LVAD and its clinical roles. The challenges and possible solutions in nursing care for pa- tients with LVAD at different stage of implantation were discussed. The healthcare professionals could obtain a better understanding about the LVAD treatment for HF patients. 展开更多
关键词 Destination therapy Heart failure Left ventricular assist device NURSING
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Optimal timing of same-admission orthotopic heart transplantation after left ventricular assist device implantation 被引量:1
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作者 Gunsagar Gulati David Ouyang +1 位作者 Richard Ha Dipanjan Banerjee 《World Journal of Cardiology》 CAS 2017年第2期154-161,共8页
AIM To investigate the impact of timing of same-admission orthotopic heart transplant(OHT) after left ventricular assist device(LVAD) implantation on in-hospital mortality and post-transplant length of stay.METHODS Us... AIM To investigate the impact of timing of same-admission orthotopic heart transplant(OHT) after left ventricular assist device(LVAD) implantation on in-hospital mortality and post-transplant length of stay.METHODS Using data from the Nationwide Inpatient Sample from 1998 to 2011, we identified patients 18 years of age or older who underwent implantation of a LVAD and for whom the procedure date was available. We calculated in-hospital mortality for those patients who underwent OHT during the same admission as a function of time from LVAD to OHT, adjusting for age, sex, race, household income, and number of comorbid diagnoses. Finally, we analyzed the effect of time to OHT after LVAD implantation on the length of hospital stay post-transplant.RESULTS Two thousand and two hundred patients underwent implantation of a LVAD in this cohort. One hundred and sixty-four(7.5%) patients also underwent OHT duringthe same admission, which occurred on average 32 d(IQR 7.75-66 d) after LVAD implantation. Of patients who underwent OHT, patients who underwent transplantation within 7 d of LVAD implantation("early") experienced increased in-hospital mortality(26.8% vs 12.2%, P = 0.0483) compared to patients who underwent transplant after 8 d("late"). There was no statistically significant difference in age, sex, race, household income, or number of comorbid diagnoses between the early and late groups. Post-transplant length of stay after LVAD implantation was also not significantly different between patients who underwent early vs late OHT. CONCLUSION In this cohort of patients who received LVADs, the rate of in-hospital mortality after OHT was lower for patients who underwent late OHT(at least 8 d after LVAD implantation) compared to patients who underwent early OHT. Delayed timing of OHT after LVAD implantation did not correlate with longer hospital stays post-transplant. 展开更多
关键词 Mechanical circulatory support Orthotopic heart transplant Bridge to transplant Left ventricular assist device outcomes
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Design and Implementation of a System for Laser Assisted Milling of Advanced Materials 被引量:2
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作者 WU Xuefeng FENG Gaocheng LIU Xianli 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第5期921-929,共9页
Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining p... Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining properties for laser assisted milling(LAML), few attempts have been made to extend LAML to machining parts with complex geometric features. A methodology for continuous path machining for LAML is developed by integration of a rotary and movable table into an ordinary milling machine with a laser beam system. The machining strategy and processing path are investigated to determine alignment of the machining path with the laser spot. In order to keep the material removal temperatures above the softening temperature of silicon nitride, the transformation is coordinated and the temperature interpolated, establishing a transient thermal model. The temperatures of the laser center and cutting zone are also carefully controlled to achieve optimal machining results and avoid thermal damage. These experiments indicate that the system results in no surface damage as well as good surface roughness, validating the application of this machining strategy and thermal model in the development of a new LAML system for continuous path processing of silicon nitride. The proposed approach can be easily applied in LAML system to achieve continuous processing and improve efficiency in laser assisted machining. 展开更多
关键词 laser assisted milling laser assisted milling device silicon nitride ceramic finite element analysis heat transfer
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EXPERIMENTAL STUDY OF RIGHT VENTRICULAR ASSIST IN ACUTE RIGHT VENTRICULAR FAILING 被引量:1
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作者 刘明辉 苏鸿熙 +3 位作者 李功宋 王加利 董超 童健 《Chinese Medical Sciences Journal》 CAS CSCD 1996年第4期239-243,共5页
The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported ... The efficacy of right atrial-pulmonary artery (RA-PA) bypass during acute right ventricular failure (RVF) produced by pulmonary artery constriction in dogs was examined in this study Control group (n=7) was supported with conventional volume loading and inotropic therapy. In the experimental animals (n=8) , RA-PA bypass was initiated 5 min. after the onset of severe RVF. Three control animals died from refractory ventricular fibrillation within one hour of RVF. No animals in the experimental group died within two hours of RA-PA bypass , but the histological study of the lungs in these animals demonstrated peribronchial , perivascular and intraalveolar hemorrhage. Light microscopic and electron microscopic examination of the myocardial specimens of the right ventricular free wall displayed the myocardial structures and ultrastructures were maintained effectively with RA-PA bypass while irreversible myocardial injuries occurred in the control animals after two hours of RVF with conventional therapy. During the 2 hours of RA-PA bypass, the hemodynamic indices were also maintained better when compared to the control animals. It may be concluded , a roller pump right ventricular assist device effectively unloads the acute failing right ventricle, maintains systemic cardiac output , and significantly reverses the myocardial ischemia during right ventricular failure, but RA-PA bypass may induce pulmonary hypertension due to increased pulmonary vascular resistance secondary to pulmonary edema and interstitial hemorrhage. 展开更多
关键词 right ventricular failure right ventricular assist device
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Left Ventricle Failure and Blood Flow Estimation for Centrifugal Blood Pumps 被引量:2
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作者 Eduardo Guy Perpetuo Bock Tarcisio Leao +1 位作者 Jeison Fonseca AronAndrade 《Journal of Mechanics Engineering and Automation》 2016年第3期162-166,共5页
This paper shows the blood flow control (FwC) performance to adjust rotational speed of an ICBP (implantable centrifugal blood pump) in order to provide an adequate flow to left ventricle in different patient cond... This paper shows the blood flow control (FwC) performance to adjust rotational speed of an ICBP (implantable centrifugal blood pump) in order to provide an adequate flow to left ventricle in different patient conditions. ICBP is a totally implantable LVAD (left ventricular assist device) with ceramic bearings developed for long term circulatory assistance. FwC uses PI (proportional-integral) control to adjust rotational speed in order to provide blood flow. FwC does not use sensor for feedback, as there is an estimation system to provide blood flow measurement. Control strategy has being studied in a HCS (hybrid cardiovascular simulator) as a tool that allows the physical connection of ICBP during evaluation. In addition, HCS allows changes of some cardiovascular parameters in order to simulate specific heart disease: ejection fraction (10-25%) and heart rate (50-110 bpm). FwC was able to adjust blood flow with steady error less than 2%. Results demonstrated that FwC is adequate to LVAD control irL different left ventricle failure conditions. 展开更多
关键词 Flow control left ventricle assist device implantable centrifugal blood pump heart failure artificial organs.
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Effective management for older people with heart failure: from acute to palliative care paradigms
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作者 Doris SF Yu 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第5期391-392,共2页
Heart failure (HF) had emerged as an epidemic since two decades ago and is now a major threatening public health problem affecting 23 million population worldwide,
关键词 Heart failure Left ventricular assist device Palliative care SELF-CARE Symptom cluster
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Computational fluid dynamics of left ventricular assist device under unsteady flow
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作者 BUMRUNGPETCH J. TAN A.C. 《排灌机械工程学报》 EI CSCD 北大核心 2016年第2期93-98,共6页
Left ventricular assist device( LVAD) in this study is a mechanical tool that is used to support blood flow in the patient with heart disease. It supports left ventricle by building up the pressure to the pump outlet ... Left ventricular assist device( LVAD) in this study is a mechanical tool that is used to support blood flow in the patient with heart disease. It supports left ventricle by building up the pressure to the pump outlet connected to the aorta. This pump was designed based on the magnetic driven centrifugal pump with a unique small washout hole constructed inside the impeller to generate the washout flow passage to prevent the stagnation at the region underneath and around the rotor. Computational fluid dynamics( CFD) was adopted in this study to assess the performance and optimize the design to avoid recirculation and high shear stress which is the main cause of stagnation and blood damage. Transient simulation was used for this study due to the asymmetric design of the washout hole and the complication of the bottom support of the impeller that has a risk of thrombosis,also,it was used to predict the variation of hydraulic performance caused by the rotation of the impeller and pulsed flow at the pump inlet. The simulation results show no excessive stress and no recirculation observed within the computational domain; in addition,the research result also provides information for further optimization and development to the pump. 展开更多
关键词 heart pump left ventricular assist device computational fluid dynamics unsteady flow
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