EXPERIMENTAL STUDIES OF RETROGRADE CEREBRAL PERFUSION UNDER CONDITION OF PROFOUND HYPOTHERMIA

本研究旨在评价深低温停循环期间逆行脑灌流的有益效果。成年杂种犬在体外循环下，鼻咽降温至20ﾟC，在此温度下进行低温停循环和逆行脑灌注60min。经双侧上颌静脉逆行脑灌注，调节逆行流量，使颈外静脉平均灌注压分别维持在10、20、30 mm Hg。我们还研究了在RCP中通过下腔静脉插管夹住血流对脑代谢的影响，以及脉动血流对逆行脑血流的影响。结果表明，RCP维持了中枢神经系统的低温、氧的供应、代谢产物的分泌、有氧代谢和脑A-TP水平，RCP适宜的灌流压力为20 mm Hg，RCP期间阻断下腔静脉插管对脑组织的保护作用更强，脉动血流逆行脑灌流较无脉动血流更有可能控制脑水肿。

This investigation was to evaluate the beneficial effect of retrograde cerebral perfusion during ciculatory arrest under condition of profound hypothermia. Adult mongrel dogs were placed on cardiopulmonary bypass and were cooled to a nasopharyngeal temperature of 20ﾟC.At this temperature, hypothermic circulatory arrest and retrograde cerebral perfusion(RCP)were performed for 60 minutes. Retrograde cerebral perfusion was performed via the bilateral maxillary veins, and retrograde flow rate was regulated to maintain a mean perfusion pressure of 10,20,30mmHg in the external jugular vein respectively. We also investigated the effects on cerebral metabolism of clamping blood flow through the IVC cannula during RCP and also investigated the effects of pulsatile flow on retrograde cerebral perfusion. Results from these investigation suggest that hypothermia of the central nervous system, the supply of oxygen, the excretion of metabolites, aerobic metabolism, and the cerebral A Tp level were maintained by RCP.A perfusion pressure of 20mmHg was appropriate for RCP and clamping of the venous blood flow through the IVC cannula during RCP is a more protective procedure for cerebral tissue during RCP.And retrograde cerebral perfusion with pulsatile flow has the possibility to control brain edema as compared with non-pulsatile flow.