Effects of rapidly induced mild hypothermia with extracorporeal lung and heart assist on the neurological outcome after prolonged cardiac arrest in dogs.

背景和目的：异丙酚在小动物模型中已被证明对神经元损伤诱导的脑缺血具有保护作用。我们先前曾报道，亚低温(33℃)联合体外循环心肺辅助(ECLHA)可改善常温15min所致心脏骤停(CA)犬的神经预后。方法：15只雌性杂种犬随机分为咪达唑仑0.1 mg/kg/h组(M组，n=5)、异丙酚2 mg/kg/h组(P2组，n=5)、异丙酚4 mg/kg/h组(P4组，n=5)。所有犬均诱发常温室颤(VF)15min，然后进行短暂ECLHA和168h的重症监护。结果：M组有1只犬死亡，其余犬存活168 h，P4组的神经功能恢复优于M组(96h，4±6%vs 19±10%，120 h，4±5%vs 19±10%，144h，3±4%vs 19±10%，P&lt；P&lt)，P<0.05，P<0.05，P<0.01，P<0.01，P<0.05，P<0.05，P2组1只犬和P4组3只犬神经功能完全恢复(NDS：0%)。结论：异丙酚4 mg/kg/h静脉滴注结合快速亚低温(33℃)与体外循环血氧饱和度(ECLHA)相结合是CA脑复苏的一种成功方法。

Background and Purpose : Propofol has been demonstrated to protect against neuronal damage-induced brain ischemia in small animal models. We previously reported that mild hypothermia(33℃) in combination with extracorporeal lung and heart assist(ECLHA) improved the neurological outcome in dogs with cardiac arrest(CA) induced by 15 min of normothermia. We investigated the neuroprotective effect of propofol infusion under mild hypothermia with ECLHA in this model.Methods : Fifteen female mongrel dogs were divided into three groups : Midazolam 0.1 mg/kg/h infusion group(M,n=5), Propofol 2 mg/kg/h infusion group(P2,n=5), Propofol 4 mg/kg/h infusion group(P4,n=5). All dogs were induced to normothermic ventricular fibrillation(VF) for 15 min, followed by brief ECLHA and 168 h of intensive care. The drug infusion was initiated at a constant rate from the establishment of the restoration of spontaneous circulation(ROSC) to 24 h. Mild hypothermia(33℃) was maintained for 20 h. Neurological deficit scores(NDS:0%=normal,100%=brain death) were evaluated for neurological function from 33 h to 168 h.Results : One dog in the M group died, and the remaining dogs survived for 168 h. The P4 group showed better neurological recovery compared with the M group(96 h,4±6% vs 19±10%,120h,4±5% vs 19±10%,144h,3±4% vs 19±10%,p<0.05).One dog in the P2 and three dogs in the P4 group achieved full neurological recovery(NDS:0%).Conclusion : The combination of propofol infusion at a rate of 4 mg/kg/h and rapidly induced mild hypothermia(33℃) with ECLHA might prove a successful means for cerebral resuscitation from CA.