Methods: Patients undergoing cardiac surgery using moderate hypothermic cardiopulmonary bypass (CPB) will be randomly allocated to get remifentanil-based propofol-supplemented (Group R) or conventional sevoflurane-sufentanil regimen (Group C) in the study period. For anesthetic induction and maintenance, fixed target controlled infusion (TCI) of remifentanil (plasma concentration 20 ng/ml) and TCI-propofol for maintaining BIS score 40-60 (effect concentration 0.8-1.5 μg/ml) in Group R, and TCI-sufentanil (Cp 0.4- 0.8 ng/ml) and sevoflurane inhalation for maintaining 80-120 % of baseline BP and BIS < 60 (< 1.5 MAC) in Group C, respectively.