ABSTRACT
Objective To investigate the effects of sevoflurane pretreatment on the myocardial injury in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Twenty NYHA class Ⅱ or Ⅲ patients,aged ＜ 60 yr,undergoing cardiac valve replacement with CPB,were randomly divided into 2 groups (n =10 each):sevoflurane group (group S) and control group (group C).The patients were premeditated with intramuscular morphine and scopolamine.Anesthesia was induced with iv injection of midazolam 0.05-0.08 mg/kg,fentanyl 10-15 μg/kg and pipecuronium 0.08-0.10 mg/kg.Anesthesia was maintained with intermittent iv boluses of midazolam,fentanyl and pipecuronium and in addition sevoflurane was inhaled before aortic clamping and the end-tidal concentration was rapidly increased to 1.0％ and maintained at the level for 5 min in group S.Blood samples were taken from the central vein before skin incision (T1),immediately after aortic clamping (T2 ),at 0 and 30 min after aortic unclamping (T3-4),and at 2,6,12 and 24 h after operation (T5-8) for determination of the concentration of serum cardiac troponin Ⅰ (cTnI) and activities of creatine kinase (CK) and creatine kinase isoenzyme-MB (CK-MB).Myocardial specimens were taken from right auricle before aortic clamping and at 10 min after aortic unclamping for electron microscopic examination.Results The concentration of serum cTnI and activities of CK and CK-MB were significantly increased at T4-8 in both groups ( P ＜ 0.05).The serum cTnI concentration at T4-8 and the activities of CK and CK-MB at T8 were significantly lower in group S than in group C ( P ＜0.05).Different degrees of mitochondrial swelling were observed after aortic unclamping in both groups,but the changes were milder in group S than in group C.Conclusion Sevoflurane pretreatment can attenuate the myocardial injury in patients undergoing cardiac valve replacement with CPB.