Lichtenstein S V, Ashe K A, el Dalati H, Cusimano R J, Panos A, Slutsky A S
Department of Surgery, St. Michael's Hospital, Toronto, Ontario, Canada.
J Thorac Cardiovasc Surg. 1991 Feb;101(2):269-74.
Hypothermia is widely acknowledged to be the fundamental component of myocardial protection during cardiac operations. Although it prolongs the period of ischemic arrest by reducing oxygen demands, hypothermia is associated with a number of major disadvantages, including its detrimental effects on enzymatic function, energy generation, and cellular integrity. We hypothesized that the ideal protected state of the heart would be electromechanically arrested and perfused with blood, that is, aerobic arrest. Under these conditions the fundamental need for hypothermia becomes questionable. We have developed a novel approach to myocardial protection during cardiac operations based on these concepts, in which the chemically arrested heart is perfused continuously with blood and maintained at 37 degrees C. In 121 consecutive coronary bypass procedures we have compared this approach with a historical cohort of 133 consecutive patients treated with hypothermic cardioplegia. Perioperative myocardial infarction was significantly less prevalent (1.7% versus 6.8%; p less than 0.05) in the warm cardioplegic group, as was the use of the intraaortic balloon pump (0.9% versus 9.0%; p less than 0.005) and the prevalence of low output syndrome (13.5% versus 3.3%; p less than 0.005). Cardiac output immediately after bypass was significantly higher than before bypass (3.1 +/- 0.9 versus 4.9 +/- 1.0 L/min; p less than 0.001) only in the warm cardioplegia group. Furthermore, the heartbeat in 99.2% of patients treated with continuous warm cardioplegia converted to normal sinus rhythm spontaneously after removal of the aortic crossclamp compared with only 10.5% of the hypothermic group. The time from removal of the aortic crossclamp to discontinuation of cardiopulmonary bypass (i.e., reperfusion time) was significantly shorter in the warm cardioplegia group (11 +/- 4.3 versus 27 +/- 5.6 minutes; p less than 0.001). Our results suggest that continuous normothermic blood cardioplegia is safe and effective. Conceptually, this represents a new approach to the problem of maintaining excellent myocardial preservation during cardiac operations.
低温被广泛认为是心脏手术中心肌保护的基本组成部分。尽管低温通过降低氧需求延长了缺血性停搏时间，但它存在许多主要缺点，包括对酶功能、能量生成和细胞完整性的有害影响。我们假设心脏的理想保护状态应该是电机械停搏并进行血液灌注，即有氧停搏。在这些条件下，对低温的基本需求就值得怀疑了。基于这些概念，我们开发了一种心脏手术中心肌保护的新方法，即对化学停搏的心脏持续进行血液灌注并维持在37摄氏度。在连续121例冠状动脉搭桥手术中，我们将这种方法与133例接受低温心脏停搏治疗的连续患者的历史队列进行了比较。在温血心脏停搏组中，围手术期心肌梗死的发生率显著较低（1.7%对6.8%；p<0.05），主动脉内球囊泵的使用情况也是如此（0.9%对9.0%；p<0.005），低心排血量综合征的发生率也是如此（13.5%对3.3%；p<0.005）。仅在温血心脏停搏组中，搭桥后即刻的心输出量显著高于搭桥前（3.1±0.9对4.9±1.0升/分钟；p<0.001）。此外，与低温组仅10.5%的患者相比，99.2%接受持续温血心脏停搏治疗的患者在移除主动脉阻断钳后心跳自发恢复为正常窦性心律。温血心脏停搏组从移除主动脉阻断钳到停止体外循环的时间（即再灌注时间）显著更短（11±4.3对27±5.6分钟；p<0.001）。我们的结果表明，持续常温血液心脏停搏是安全有效的。从概念上讲，这代表了一种在心脏手术中维持优异心肌保护问题的新方法。
