Assuntos
Casamento , Médicas , Profissionalismo/ética , Cônjuges/psicologia , Cirurgiões/psicologia , Cirurgia Torácica , Equilíbrio Trabalho-Vida/organização & administração , Escolha da Profissão , Relações Familiares , Papel de Gênero , Humanos , Parto , Médicas/ética , Médicas/psicologia , Responsabilidade Social , Direitos da Mulher/éticaRESUMO
INTRODUCTION: Implementation of continuous flow (CF) technology in modern ventricular assist devices (VAD) has afforded a wealth of engineering and design advantages in the development of a total artificial heart (TAH). However, clinical application of CF has created a unique physiologic state, the consequences of which remain largely unknown. We sought to evaluate clinical and biochemical markers of end-organ function in calves supported with biventricular CF VADs for more than 30 days. METHODS: Eight calves survived longer than 30 days following biventriculectomy and implantation of dual CF VADs. Four types of CF pumps were utilized for the study. Serial hematologic and biochemical profiles were drawn as markers for end-organ function, and hemodynamic data-including pump flows and intravascular pressures-were continuously monitored. RESULTS: The eight calves survived an average of 58.8 days (range 30-92 days). Two of the calves were electively terminated at the conclusion of the study period, while the remaining animals were euthanized as a result of respiratory distress (n = 2) or impaired pump flows (n = 4). In each case, serial biochemical and hematologic values were suggestive of preserved end-organ function. Six animals successfully participated in treadmill exercise evaluations. No evidence of end-organ damage was encountered upon necropsy or histologic tissue analysis. CONCLUSION: Biventricular CF VAD implantation permits a viable bovine CFTAH model capable of demonstrating long-term survival. After 30 days of completely nonpulsatile flow, cumulative hemodynamic, clinical, biochemical, and histological analyses were consistent with preserved end-organ function, suggesting previously unreported long-term feasibility of a CFTAH design.
Assuntos
Insuficiência Cardíaca , Coração Artificial , Coração Auxiliar , Animais , Bovinos , Teste de Esforço , Estudos de Viabilidade , Insuficiência Cardíaca/terapia , HemodinâmicaRESUMO
The widespread use of continuous-flow left ventricular assist devices for mechanical circulatory support has shown that long-term hemodynamic support is possible, even when a clinical "pulse" cannot be detected. We present the incidental discovery of ventricular fibrillation in 6 alert, hemodynamically stable patients supported only by a continuous-flow device (HeartMate II, n=5; Jarvik 2000, n=1). Ventricular fibrillation was found in 3 patients during routine outpatient follow-up visits and in 3 awaiting discharge from the hospital after device placement. Diagnosis was confirmed by electrocardiographic and echocardiographic studies. The average duration of mechanical circulatory support before ventricular fibrillation occurred was 221 ± 362 days (range, 5-864 d). All patients were conscious and ambulatory at the time of the arrhythmia. Three patients reported symptoms-primarily fatigue, nausea, and exertional dyspnea-that prompted evaluation. Serum chemistry analysis of blood drawn immediately after diagnosis showed no changes that suggested end-organ dysfunction. Three patients died of unrelated complications an average of 3.9 yr (range, 360-2,270 d) after the event. Two of the remaining 3 patients eventually underwent successful pump explantation, and one is on ongoing support. Our experience shows that it is possible for patients with continuous-flow left ventricular assist devices to remain hemodynamically stable while in ventricular fibrillation. Additional investigation is needed to determine whether defibrillator settings for these patients should be adjusted to limit delivery of shock therapy.
Assuntos
Remoção de Dispositivo/métodos , Insuficiência Cardíaca/terapia , Coração Auxiliar/efeitos adversos , Complicações Pós-Operatórias , Fibrilação Ventricular/etiologia , Adulto , Idoso , Ecocardiografia Transesofagiana , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/cirurgia , Adulto JovemRESUMO
Air embolism is a rare and usually fatal complication of major cardiac surgery. We present a case in which a 45-year-old man supported by a HeartMate(R) XVE left ventricular assist device required a pump exchange due to failure of the device motor. During pump dissection, a massive amount of air entered the systemic circulation. Urgent cannulation for cardiopulmonary bypass was performed, and cardiopulmonary bypass was initiated, followed by profound hypothermia, circulatory arrest, retrograde cerebral perfusion, retrograde coronary sinus perfusion, and then barbiturate coma and steroid therapy. The HeartMate XVE left ventricular assist device was removed, and a HeartMate II was implanted. After 5 days, the patient awoke with left hemiparesis, which nearly resolved with aggressive physical therapy. Forty-four days after the pump exchange operation, the patient was discharged from the hospital with only mild left hemiparesis. Exposure of the left ventricular assist device or its external components requires careful monitoring, because air can enter the pump-particularly in a hypovolemic patient. Rapid response after massive air entry into the left ventricular assist device system, as in our patient, can result in a successful outcome.
Assuntos
Embolia Aérea/etiologia , Coração Auxiliar/efeitos adversos , Embolia Intracraniana/etiologia , Ponte Cardiopulmonar , Parada Circulatória Induzida por Hipotermia Profunda , Embolia Aérea/cirurgia , Falha de Equipamento , Insuficiência Cardíaca/cirurgia , Humanos , Embolia Intracraniana/cirurgia , Masculino , Pessoa de Meia-Idade , Paresia/etiologiaRESUMO
In adult patients, mechanical circulatory support (MCS) devices are part of the standard of care for heart failure. There are several options available that clinicians may use to provide support for their patients and thus the choice of devices can be tailored to their individual needs. Unfortunately, this is not the case for pediatric patients with heart failure, where the options for MCS modalities are far more limited because of size constraints and regulatory hurdles. Furthermore, the pathophysiology of heart failure in children is not identical to that of adults; thus, the device selection and configuration require different considerations. Management of pediatric patients on MCS requires a highly specialized team of pediatric professionals. The nurse caring for a child on MCS is an active participant in all aspects of the patient's care and must have an in-depth understanding of the patient's underlying physiology, the circulatory physiology of the MCS system, the reason for mechanical support, and the goal of support.
Assuntos
Circulação Assistida/enfermagem , Cuidados Críticos/métodos , Insuficiência Cardíaca/terapia , Papel do Profissional de Enfermagem , Atividades Cotidianas , Adolescente , Fatores Etários , Circulação Assistida/efeitos adversos , Circulação Assistida/instrumentação , Circulação Assistida/tendências , Criança , Pré-Escolar , Desenho de Equipamento , Insuficiência Cardíaca/psicologia , Transplante de Coração , Humanos , Lactente , Recém-Nascido , Avaliação em Enfermagem , Seleção de Pacientes , Enfermagem Pediátrica/métodos , Assistência Perioperatória/métodos , Assistência Perioperatória/enfermagem , Psicologia da Criança , Qualidade de Vida , Fatores de Risco , Listas de EsperaRESUMO
In this study, long-term (90-day) hemocompatibility and end-organ effects of a centrifugal left ventricular assist device (the Heartware HVAD) were evaluated in 6 healthy sheep. The device was implanted into the left ventricular apex on beating hearts. The outflow graft of each device was anastomosed to the descending aorta. None of the sheep received anticoagulation or antiaggregation medication during the study. Hematologic and biochemical tests of liver and kidney function were performed pre-operatively (baseline) and throughout the study. Data associated with pump function were collected continuously until 90 +/- 1 days of support, at which time the sheep were humanely killed, and the end-organs were examined macroscopically and histopathologically. Hematologic and biochemical test results were within normal limits during the study period. There were no significant complications. Postmortem examination of the explanted organs revealed no evidence of ischemia or infarction, except in 2 sheep, in which small foci of infarction were detected in each of their left kidneys. There was no significant device failure. In all sheep, the pump's inflow and outflow conduits were free of thrombus. During the 90-day study, the HeartWare HVAD showed exceptional hemocompatibility and reliability, both of which are crucial to the clinical success of any implantable left ventricular assist device.
Assuntos
Materiais Biocompatíveis , Insuficiência Cardíaca/cirurgia , Coração Auxiliar , Implantação de Prótese/instrumentação , Animais , Modelos Animais de Doenças , Contagem de Eritrócitos , Seguimentos , Insuficiência Cardíaca/sangue , Ventrículos do Coração/patologia , Hematócrito , Desenho de Prótese , Reprodutibilidade dos Testes , OvinosRESUMO
The TandemHeart percutaneous ventricular assist device can be used to support patients in cardiogenic shock (until cardiac recovery occurs or as a bridge to definitive therapy) or as a temporary application during high-risk coronary interventions. The TandemHeart is a left atrial-to-femoral artery bypass system comprising a transseptal cannula, arterial cannulae, and a centrifugal blood pump. The pump can deliver flow rates up to 4.0 L/min at a maximum speed of 7500 rpm. From May 2003 through May 2005, the TandemHeart was used to support 18 patients (11 in cardiogenic shock and 7 undergoing high-risk percutaneous transluminal coronary angioplasty). The patients in cardiogenic shock were supported for a mean of 88.8 +/- 74.3 hours (range, 4-264 hr) at a mean pump flow rate of 2.87 +/- 0.56 L/min (range, 1.8-3.5 L/min). The mean cardiac index improved from 1.57 +/- 0.31 L/min/m2 before support to 2.60 +/- 0.34 L/min/m2 during support. The mean duration of support for the high-risk percutaneous transluminal coronary angioplasty patients was 5.5 +/- 8.3 hours (range, 1-24 hr). The mean flow rate was 2.42 +/- 0.55 L/min (range, 1.5-3.0 L/ min). The overall 30-day survival rate was 61%. In our experience, the TandemHeart device was easy to insert and provided a means either to cardiac recovery or to continued support with an implantable left ventricular assist device.
Assuntos
Coração Auxiliar , Idoso , Idoso de 80 Anos ou mais , Angioplastia Coronária com Balão , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Choque Cardiogênico/terapiaRESUMO
Since the 1960s, the Texas Heart Institute has been intimately involved in the development of mechanical circulatory support devices (for example, ventricular assist devices, aortic counterpulsation pumps, and total artificial hearts) for both short- and long-term use. Here, we review the varied clinical experience with these technologies at the Texas Heart Institute over the last 35 years.