Mussivand T V, Masters R G, Hendry P J, Keon W J
Cardiovascular Devices Division, University of Ottawa Heart Institute, Ontario, Canada.
Ann Thorac Surg. 1996 Jan;61(1):444-7. doi: 10.1016/0003-4975(95)01008-4.
A totally implantable, intrathoracic electrohydraulic ventricular assist device (EVAD) is being developed for permanent use or as a bridge to transplantation.
The blood pump with 70-mL nominal stroke volume, volume displacement chamber, reversible turbine, internal electronics and infrared diaphragm position sensor are combined in one compact unit (unified system). The size and geometry are based on human anatomic measurements and fluid dynamic studies. A transcutaneous energy transfer powers the system and recharges the implantable nickel-cadmium battery pack. Autotuning circuitry optimizes energy transfer efficiency over a range of transcutaneous energy transfer coil spacings and misalignments. An infrared diaphragm position sensor detects end-systole and diastole points.
In vitro and acute in vivo tests have demonstrated flow rates greater than 6 L/min. The transcutaneous energy transfer system demonstrated power transfer efficiencies of 60% to 80% for power demands from 5 to 60 W. Thirteen systems are currently undergoing durability testing; one has run for more than 750 days failure-free. The system recently sustained circulation in an acute calf implantation for 96 hours.
Results of the in vitro and in vivo testing to date have demonstrated that the developed system can function effectively as a totally implantable ventricular assist device. Chronic in vivo evaluation is planned.
一种完全植入式的胸腔内电动液压心室辅助装置（EVAD）正在研发中，用于长期使用或作为移植桥梁。
具有70毫升标称冲程容积的血泵、容积置换腔、可逆涡轮、内部电子设备和红外隔膜位置传感器组合在一个紧凑单元（统一系统）中。其尺寸和几何形状基于人体解剖测量和流体动力学研究。经皮能量传输为系统供电并为可植入镍镉电池组充电。自动调谐电路可在一系列经皮能量传输线圈间距和未对准情况下优化能量传输效率。红外隔膜位置传感器检测收缩末期和舒张末期点。
体外和急性体内测试表明流速大于6升/分钟。经皮能量传输系统在5至60瓦的功率需求下，功率传输效率为60%至80%。目前有13个系统正在进行耐久性测试；其中一个已无故障运行超过750天。该系统最近在急性小牛植入中维持循环96小时。
迄今为止的体外和体内测试结果表明，所开发的系统可作为完全植入式心室辅助装置有效发挥作用。计划进行慢性体内评估。
