Methods: Forty patients who were scheduled for elective offpump CABG surgery were randomly assigned to two groups. The remifentanil group received 1 μg/kg^-1 remifentanil over one minute for induction, followed by 0.1-1 μg/kg^-1 min^-1 continuous infusion plus midazolam 0.1-0.15 mg/kg^-1 for maintenance dose. The fentanyl group received 10-15 μg/kg^-1 fentanyl over one minute for induction and 0.1-1 μg/kg^-1 min^-1 continuous infusion plus midazolam 0.1-0.15 mg/kg-1 for maintenance dose. Rocuronium bromide at 0.6-0.8 mg/kg^-1 was administered to facilitate tracheal intubation. Midazolam infusion at 0.4-1 μg/kg^-1 min^-1 was initiated for maintenance therapy.

Results: The depth of anesthesia was adjusted to maintain a BIS value between 40-60. Following skin incision and sternotomy, systolic arterial pressure was lower in the remifentanil group compared to the fentanyl group (115±14 mmHg vs. 130±22 mmHg p<0.05; 125±14 mmHg vs. 135±19 mmHg, p<0.05). Total dose of midazolam was significantly higher in the remifentanil group compared to the fentanyl group (13.9±3.7 mg vs. 11.6±3.7 mg, p<0.05). Intraoperative use of beta blockers, nitroglycerine and sodium nitroprusside was similar in both groups. The median time to extubation and the length of stay in the intensive care unit were shorter in the remifentanil group (6.5±3 h vs. 10±3 h, p<0.05; 14±6 h vs. 20±6 h, p<0.05). The incidence of postoperative electrocardiographic changes and troponin I measurements were similar in both groups.

Conclusion: Although remifentanil infusion offers a better intraoperative hemodynamic stability and postoperative recovery, both agents have similar effects on myocardial injury during offpump CABG surgery.