停跳和不停跳行心脏直视手术对心肌保护作用的对比研究

目的：探讨浅低温体外循环(CPB)下温血停搏液持续灌注和不停跳行心内直视手术对心肌的保护作用。方法：18只同种健康山羊采用单盲法随机分为冷晶体间断灌注组(Ⅰ组)，温血停搏液持续灌注组(Ⅱ组)，不停跳组(Ⅲ组)3组，每组6只；分别在CPB的不同时刻测定心肌组织丙二醛(MDA)含量及静脉血心钠素(ANP)含量，并切取心肌组织在电镜下观察超微结构的改变。结果：Ⅰ组MDA和ANP在CPB期间逐渐升高，恢复正常灌注后升高更明显：Ⅱ组、Ⅲ组MDA和ANP虽也有所升高，但较Ⅰ组低，且恢复正常灌注后无升高趋势。心肌超微结构也显示Ⅰ组改变明显，而Ⅱ组、Ⅲ组则基本不变。结论：温血停搏液持续灌注和不停跳行心内直视手术可有效避免心肌的缺血和再灌注损伤，有良好的心肌保护作用。

Experimental study of myocardial protective effect of cardiac arrest versus beating heart during open heart surgery

OBJECTIVE: To investigate the myocardial protective effects of beating heart versus heart arrest in goats undergoing open heart surgery with cardiopulmonary bypass (CPB). METHODS: Eighteen healthy and homologous goats were randomly divided into three groups: groupI (n=6), with intermittent cold crystalloid cardioplegia; group II (n=6), with continuous warm blood cardioplegia; group III (n=6), with beating heart. Animals in group II and group III were operated with mild hypothermic CPB. The changes in malondialdehyde (MDA) in the myocardium of the right ventricles and atrial natriuretic peptide (ANP) in venous blood were measured respectively. The myocardial tissues were examined for ultrastructural changes. RESULTS: In group I, contents of MDA and ANP rose significantly during CPB, especially when blood was reperfused routinely. While in group II and group III, the levels were lower than those in group I at the same time points. There was no difference in the values between group II and group III. Ultrastructural changes were distinctly seen in group I, while they were mild in group II and group III. CONCLUSION: Continuous warm blood cardioplegia to keep the heart beating during operation can prevent ischemia-reperfusion injury and protect heart better.