长时间阻断主动脉的心肌保护与辅助循环脱机指征

Myocardial Protection on Prolonged Cardiac Ischemia and Indexes for Weaning from Cardiopulmonary Bypass

长时间的心肌缺血是影响心肌保护的重要因素，也是不能脱离体外循环的常见原因之一。本文报告了４１例长时间阻断主动脉的心肌保护方法与辅助循环脱机指征，其中主动脉阻断时间（ＡＣＣＴ）＞１２０分３２例，ＡＣＣＴ＞１８０分９例；主动脉根部间断顺行灌注停搏液１４例；顺行灌注联合间断逆行灌注含血停搏液２０例；顺行灌注联合持续逆行灌注７例；主动脉开放前控制性热血再灌注１４例；结果显示：顺行灌注联合持续逆行灌注对心肌保护效果最佳，它可使主动脉阻断的安全时限达４小时左右。本文还就辅助循环方法与脱机指征进行讨论。作者主张根据左房压和平均动脉压的动态变化，调解辅助循环流量是脱机的可靠方法。

Long time heart ischemia is one of the important factors influencing intraoperative myocardial protection,and also a common cause resulting in the failure of weaning from cardiopulmonary bypass(CPB).This paper reported the myocardial protection method and indexes for CPB discontinuation of 41 patients with aortic crossclamping time(ACCT)over 2 hrs, among which 9 patients were with ACCT more than 3 hrs.Aortic root antagrade cardioplegia was delivered in 14 cases;antagrade combined with intermittent retrograde cardioplegia in 20 cases and antagrade combined with continuous retrograde cardioplegia in 7 cases.In addition,terminal warm blood cardioplegia containing mannitol was used in 7 cases.Our results indicate that antagrade combined with continuous retrograde cardioplegia has superior advantages to myocardial protection, which cna expand the safe time limit of heart ischemia up to 3～4 hrs with satisfied clinical results.This paper also discussed the method of assist circulation and indexes of weaning from CPB.We recommended dynamic changes of left atrial pressure and mean arterial blood pressure as indicators for the regulation of perfusion flow rate.