Effects of sevoflurane postconditioning on myocardial ischemia-reperfusion injury in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass

Abstract

Objective To investigate the effects of sevoflurane postconditioning on myocardial ischemiareperfusion(I/R)injury in patients undergoing coronary artery bypass grafting(CABG)with cardiopulmonary bypass(CPB).Methods Forty NYHA Ⅰ -Ⅲ patients of both sexes,aged 55-64 yr,with BMI ＜ 30 kg/m2,scheduled for CABG under CPB,were randomly divided into 2 groups(n = 20): control group(group C)and sevoflurane postconditioning group(group S).Anesthesia was induced with midazolam and/or etomidate,fentanyl and rocuronium.Patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with iv infusion of propefol and intermittent iv injection of fentanyl and pipecuronium.In group S,2% sevoflurane was inhaled continuously for 15 min immediately after aortic unclamping.After anesthesia induction,before CPB,10 min after the end of CPB,at the end of operation,and 6 and 24 h after operation,MAP,HR,CVP,mean pulmonary arterial pressure,pulmonary arterial wedge pressure,CO and S(v)O2 were recorded,and CI,SVI,systemic vascular resistance index and pulmonary vascular resistance index were calculated.Blood samples were taken from central vein before aortic clamping,at 6 h of reperfusion and 24 h after operation for determination of plasma creatine kinase(CK),creatine kinase isoenzyme(CK- M B)and lactate dehydrogenase(LDH)activities and tropenin I(TnI)concentrations.Myocardial tissues were obtained from right auricle before aortic clamping and at the end of CPB for observation of the ultrastructure and the severity of myocardial injury was assessed.Results There was no significant difference in hemodynamics and parameters of cardiac function between the two groups(P ＞ 0.05).Compared with group C,plasma CK-MB and LDH activities at 6 h of reperfusion and plasma CK activity and TnI concentrations at 24 h after operation were significantly decreased and the myocardial injury was significantly reduced after the end of CPB in group S(P ＜ 0.05).Conclusion Sevoflurane postconditioning can protect myocardium against I/R injury induced by CPB in patients undergoing CABG. Key words: Anesthetics,inhalation; Myocardial reperfusion injury; Cardiopulmonary bypass