［摘要］目的：研究婴幼儿心内直视手术灌注不同停跳液心肌细胞丙二醛（MDA）和超氧化物歧化酶（SOD）的变化，探讨自体冷血停跳液对婴幼儿心肌保护的作用机制。方法：30例非紫绀型先天性心脏病婴幼儿（体重≤8kg），随机分为晶体液组、冷血组和自体冷血停跳液组，每组10例。分别于心脏停跳前、复跳后取右心耳心肌，检测心肌MDA和SOD含量。术中记录复跳时间、自动复跳率和室颤发生率。术后监测心脏指数（CI），正性肌力药物依赖情况。结果：术前3组MDA分别为（0.87±0.14）、（0.88±0.11）、（0.86±0.15）nmol/mg prot；SOD分别为（61.3±3.4）、（69.2±3.1）、（64.4±4.2）U/g，差异无显著性（P>0.05）；同组术后与术前比较，MDA明显升高，分别为（3.12±0.21）、（2.93±0.27）、（1.67±0.15）nmol/mg prot，SOD明显降低（42.6±2.3）、（44.6±3.1）、（57.7±2.1）U/g，差异有显著性（P<0.05或P<0.01）；术后自体冷血组与晶体液组、冷血组冷血比较，MDA含量降低，SOD含量升高，复跳时间缩短，正性肌力药物依赖性降低，CI升高，差异均有显著性（P<0.05或P<0.01）；晶体液组与冷血组比较，复跳时间、正性肌力药物依赖性及CI差异有显著性（P<0.05或P<0.01）。结论：自体冷血停跳液对婴幼儿心内直视手术心肌保护主要作用机制是降低心肌细胞氧自由基的产生。［中国当代儿科杂志，2009，11（8）：638-640］

OBJECTIVE: To study the effects of cold autoblood cardioplegia on oxygen free radicals in the myocardium in infants who underwent cardiopulmonary bypass and to explore the possible mechanism of myocardial protection of autoblood cardioplegia. METHODS: Thirty infants with acyanotic congenital heat disease (CHD) (weight≤8 kg) were randomized to receive cold crystalloid, cold blood or cold autoblood cardioplegia (n=10 each group) during cardiopulmonary bypass. The biopsy samples were taken from the right atrium just before heart arrest and after heart self-recovery for the measurement of malonaldehyde (MDA) and superoxide dismutase (SOD) contents. The time and the rate of the heart self-recovery to sinus rhythm, and the incidence of ventricular fibrillation were recorded during operation. The cardiac index (CI) and the dependence of positive inotropic drugs were monitored after operation. RESULTS: Before the operation, there were no significant differences in myocardial MDA (0.87±0.14, 0.88±0.11 and 0.86±0.15 nmol/mg prot, respectively) and SOD contents (61.3±3.4, 69.2±3.1 and 64.4±4.2 U/g, respectively) among the crystalloid, the blood and the autoblood cardioplegia groups. After operation, the myocardial MDA content increased (3.12±0.21, 2.93±0.27 and 1.67±0.15 nmol/mg prot, respectively) and SOD content (42.6±2.3, 44.6±3.1 and 57.7±2.1 U/g, respectively) decreased significantly in the three groups (P<0.05 or 0.01). The autoblood cardioplegia group had lower myocardial MDA content and higher SOD content than the crystalloid and the blood cardioplegia groups (P<0.05). The time of heart self-recovery was shortened and the dependence of positive inotropic drugs were reduced in the autoblood cardioplegia group compared with the crystalloid and the blood cardioplegia groups (P<0.05). Post-operational CI in the autoblood cardioplegia group was significantly higher than that in the blood and the crystalloid cardioplegia groups. There were significant differences in the time of heart self-recovery, the dependence of positive inotropic drugs and the CI between the blood and the crystalloid cardioplegia groups (P<0.05 or 0.01). CONCLUSIONS: Cold autoblood cardioplegia reduces oxygen free radicals in the myocardium, thus providing myocardial protections in infants undergoing cardiopulmonary bypass.［Chin J Contemp Pediatr, 2009, 11 (8):638-640］