Effects of sevoflurane postconditioning on myocardial oxidative stress in patients undergoing cardiac valve replacement with cardiopulmonary bypass

Abstract

Objective To evaluate the effects of sevoflurane postconditioning on myocardial oxidative stress in the patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Fifty ASA physical status Ⅱ or Ⅲ patients (NYHA Ⅱ or Ⅲ) of both sexes,aged 36-59 yr,weighing 42-71 kg,with rheumatic heart disease undergoing cardiac valve replacement under CPB,were randomly divided into control group (group C,n =25) and sevoflurane postconditioning group (group S,n =25).In group S,4 ％ sevoflurane was infused for 10 min via the extracorporeal circulation machines starting from the time point immediately after aortic unclamping.Before aortic clamping and at 15 min,30 min,6 h,and 24 h after aortic unclamping (T1-5),blood samples were collected from the central vein for determination of the levels of cardiac troponin I (cTnI) in plasma.Myocardial specimens were taken from the left auricle before CPB and after termination of CPB for determination of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity.The restoration of spontaneous heart beat,reperfusion arrhythmia scores,and requirement for vasoactive drugs were recorded.Results Compared with group C,MDA content was significantly decreased,and SOD activity was increased after termination of CPB,the plasma cTnI concentration was decreased at T2-5,the rate of restoration of spontaneous heart beat was increased,reperfusion arrhythmia scores were decreased,and the requirement for dopamine and nitroglycerin was reduced in group S.Conclusion Sevoflurane postconditioning provides myocardial protection by reducing myocardial oxidative stress injury in the patients undergoing cardiac valve replacement with CPB. Key words: Oxidative stress ; Myocardium ; Sevoflurane