N-乙酰半胱氨酸对体外循环下心脏瓣膜置换术患者心肌缺血再灌注损伤的影响

目的 探讨N-乙酰半胱氨酸对体外循环(CPB)下心脏瓣膜置换术患者心肌缺血再灌注损伤的影响.方法 择期CPB下行心脏瓣膜置换术的风湿性心脏病患者22例,性别不限,年龄21-60岁,ASA Ⅱ或Ⅲ级,心功能Ⅱ或Ⅲ级,随机分为2组(n=11):对照组(C组)和N-乙酰半胱氨酸组(N组).N组预充液中加入N-乙酰半胱氨酸100 mg/kg,停搏液中加入50 mg/kg,C组给予生理盐水替代.于麻醉诱导前10 min和术毕时,记录HR、MAP、中心静脉压(CVP)、肺动脉压(PAP)、肺毛细血管楔压(PCWP)、心输出量(CO)和心脏指数(CI).于切皮前即刻、主动脉开放后0.5、6、12和24 h时,采集桡动脉血样行血气分析,采集中心静脉血样测定血浆白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)、丙二醛(MDA)、心肌肌钙蛋白I(cTnI)的浓度和超氧化物歧化酶(SOD)活性.于CPB前即刻和停机即刻,取心肌组织,计数凋亡细胞,观察心肌细胞超微结构.结果 与c组比较,N组HR、MAP、CVP、PAP、PCWP、pH值、红细胞压积、动脉血氧分压、动脉血二氧化碳分压和剩余碱差异无统计学意义(P>0.05),主动脉开放后TNF-α、IL-6、cTnI和MDA的浓度降低,SOD活性升高,CPB停机即刻心肌凋亡细胞计数降低,术毕CO和CI升高(P<0.05或0.01),心肌病理损伤减轻.结论 N-乙酰半胱氨酸可减轻体外循环下心脏瓣膜置换术患者心肌缺血再灌注损伤.

Effects of N-acetylcysteine on myocardial ischemia-reperfusion injury in patients undergoing cardiac valve replacement under CPB

Objective To investigate the effects of N-acetylcysteine(NAC)on myocardial ischemia-reperfusion(I/R)injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass(CPB).Methods Twenty-two ASA Ⅱ or Ⅲ patients of both sexes aged 21-60 yr undergoing cardiac valve replacement under CPB were randomly assigned to one of 2 groups(n=11 each):control group(group C)and NAC group.In NAC group NAC 100 mg/kg was added to the priming solution and 50 mg/kg to crystalloid eardioplegic solution,while in control group normal was used instead of NAC.Swan-Gang catheter was placed.Heart rate(HR),mean arterial pressure(MAP),central venous pressure(CVP),pulmonary medal pressure(PAP),pulmonary capillary wedg pressure(PCWP),cardiac output(CO)and cardiac index(CI)were recorded at 10 min beforeanesthesia induction and at the end of operation.Blood samples were collected before operation and at 0.5,6,12 and 24 h after release of the aortic cross-clamp for determination of blood gas analysis,plasma IL-6,TNF-α,MDA and cTnI concentrations and SOD activity.Myocardial specimens were obtained from right atrium for detection of apeptosis(by TUNEL)and examination of ultrastructure with scanning electron microscope.Results There was no significant difference in HR,MAP,CVP,PAP,PCWP,PaO2,Hct,PaCO2,pH value and BE between bothgroups.The plasma concentrations of MDA,IL-6,TNF-α and eTnI weFe significantly lower,while plasma SOD activity CO and CI were higher in group NAC than in group C.NAC significantly decreased myocardial apeptosis and damage induced by myocardial I/R during CPB.Conclusion NAC can protect myocardium against I/R injury induced by CPB.