Effect of Propofol on Cardioprotective Role of Remote Ischemic Preconditioning (RIPC)

Effect of Propofol on Cardioprotective Role of Remote Ischemic Preconditioning (RIPC)

This study involves research using human subjects (cardiac surgical patients) to evaluate the effect of remote ischemic preconditioning (RIPC) on cardioprotective outcomes. RIPC applied to upper or lower extremities has been shown cardioprotective role by lowering release of cardiac troponin in patients with cardiac diseases. However, it is not clear whether anesthetics, such as propofol or sevoflurane, may impair the cardioprotective effect of RIPC in cardiac surgical patients. Therefore, the purpose of the study is to compare the effects of anesthetics on cardioprotection of RIPC in patients undergoing cardiac surgery.

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.

Inclusion Criteria:

• ASA class I~III patients undergoing cardiac surgery using cardiopulmonary bypass

Exclusion Criteria:

• Cardiac surgery without using cardiopulmonary bypass
• Descending thoracic aortic surgery
• Strenuous exercise, excessive alcohol or caffeine intake 24 hours before remote ischemic preconditioning
• Left ventricular ejection fraction < 30%
• Uncontrolled hypertension or diabetes mellitus
• Severe renal or hepatic dysfunction
• Patients on hemodialysis
• Patients with arterio-venous fistula on arms or any reason to protect arms
• Peripheral vascular or nerve disease, bleeding tendency
• Preoperative use of IABP, ECMO, or ventricular assist devices
• Emergency operation, redo operation
• Refuse to enroll
• Pregnancy
• Preoperative use of beta-blockers