Development of a pulsatile perfusion apparatus for heart preservation with myocardial impedance monitor

本研究旨在研制一种便携式心脏灌注仪，通过脉搏泵低温灌流心脏24小时，并连续测量心肌阻抗以评估心肌水肿。首先，我们以兔离体心为实验材料，以朗宁多夫为对照，对简单浸泡保存方法进行了评价。犬原位心脏移植后，在UW液中保存24小时的左心功能优于生理盐水和改良再灌注液，去白细胞终末停搏液，增强左心功能以维持正常循环。研制了一种利用电磁功率驱动膜片产生脉动流的便携式灌注仪。体外实验表明，每搏输出量0.05~5ml，搏动/分钟60~120次，灌流压力15~150毫米汞柱，可用于兔离体心的灌流。然而，由于室温的影响，在24小时的灌流过程中，温度很难维持到10摄氏度，特别是当需要“便携式”设备时。此外，常规的阻抗测量仪应该在恒温下使用，事实证明，变温下的组织阻抗值是不可靠的，没有价值。

This study was done to develop a portable perfusion apparatus for heart preservation in which hearts are hypothermically perfused with pulsatile pump for 24 hours and myocardial impedance is continuously measured to assess the myocardial edema. At first we evaluated simple immersion methods for preservation as control with Langendorf using isolated rabbit heart. The left ventricular function after 24 preservation in UW solution was better than in saline and modification at reperfusion, leukocyte depleted terminal cardioplegia, enhanced LV function to sustain the normal circulation after orthotopic heart transplantation in dog. The portable perfusion apparatus with a diaphragm driven by electromagnetic power which derivesd pulsatile flow was made. In vitro test with the apparatus showed 0.05-5ml of stroke volume, 60-120 beat/min, and 15-150 mmHg of perfusion pressure which could be controllable for isolated rabbit heart perfusion. The temperature, however, was difficult to maintain to 10 C during 24 hours perfusion because of the effect of room temperature especially when a "portable" apparatus was desired. Moreover conventional impedance meter should be used at constant temperature and it was proved that the value of tissue impedance at variable temperature was unreliable and worthless.