Abstract: 【Abstract】 Objective：To discuss the feasible anesthesia method in elderly patients undergoing off-pump Coronary Artery Bypass Grafting(OPCABG) through compare the postoperative cognitive function between Sevoflurane and Isoflurane inhaled anesthesia. Methods：Sixty undergoing elective OPCABG patients aged 65~82,heart function Ⅱ or Ⅲ ,were randomly divided into two groups: Sevoflurane group(S,n=30) and Isoflurane group(I,n=30).The blood samples of internal jugular vein were taken for determination of serum S-100 protein,neuronspecific enolase(NSE) content at the moment after anesthesia induction(T0),the end of operation(T1),6 h after operation(T2) and 24 h after operation(T3).A mini-mental state examination(MMSE) was performed 1 d before and 3,7 d after operation by an experienced psychometrician.The total scores of MMSE was 30 points.Those scores not reach 24 points were defined as postoperative cognitive dysfunction(POCD). Results：There was no significant difference in general conditions between both groups(P>0.05).All patients completed MMSE.The incidence of POCD within 7 d after operation in group I(20%) was higher than that in group S(13%)(P<0.05).The scores of MMSE at 3,7 d after operation were lower than that at 1 d before operation in both groups(P>0.05).The contents of serum S-100 protein and NSE increased at the initial stages of operation,reached peak at T1(P<0.05),then decreased at T2 (P<0.05),and returned to baseline level at T3 in both groups(P>0.05).The contents of serum S-100 protein and NSE were lower in group S than those in group I at T1 and T2(P<0.05). Conclusion： Sevoflurane can cause slighter cerebral injury and lower incidence of POCD than Isoflurane in elderly patients undergoing OPCABG,which is a recommendable anesthesia method that could be used for prevent cognitive dysfunction after heart operation.

Key words: Sevoflurane, Isoflurane, Cardiopulmonary bypass, Coronary artery bypass grafting, Cognitive function