Patients undergoing cardiac surgery using cardiopulmonary bypass will be randomized to control, propofol, or sevoflurane group. Patients in the control group will receive remote ischemic preconditioning (RIPC) on their upper arms before anesthetic induction. Patients in the propofol or sevoflurane groups will receive RIPC after anesthetic induction using propofol or sevoflurane, respectively. In all patients, arterial blood samples will be obtained before and after each RIPC. From the samples, human dialysate will be obtained and perfused to rat heart through Langendorff apparatus before ischemia-reperfusion injury to the rat heart. Infarct size of the sectioned rat heart will be compared among the three - control, propofol, and sevoflurane - groups.