Efficacy and safety of remifentanil in coronary artery bypass graft surgery: a randomized, double-blind dose comparison study.

OBJECTIVES

To compare the efficacy and safety of 3 doses of remifentanil as part of a total intravenous anesthesia technique with low-dose propofol in patients undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Multicenter, multinational, double-blind, randomized, dose comparison study.

SETTING

Nine hospitals in 5 countries.

PARTICIPANTS

One hundred forty-one patients undergoing first-time elective CABG surgery.

INTERVENTIONS

Patients were premedicated with a short-acting oral benzodiazepine up to 2 h before surgery and randomized to receive continuous infusions of remifentanil 1.0 microg/kg/min (n = 45), 1.5 microg/kg/min (n = 44), or 2.0 microg/kg/min (n = 43), in combination with propofol 3 mg/kg/h. Nine patients received remifentanil 1.0 microg/kg/min on an open-label basis. Three different induction sequences (IS) were used. In IS 1 (n = 31), induction was started with remifentanil infusion followed 5 minutes later by propofol 0.5 mg/kg bolus and infusion at 3 mg/kg/h. Further bolus doses of propofol (10 mg) were given if loss of consciousness (LOC) was not attained after 5 minutes; pancuronium, 0.04 to 0.1 mg/kg, was administered at LOC. In IS 2 (n = 68), a priming dose of pancuronium, 0.015 mg/kg, was administered just before starting remifentanil. In IS 3 (n = 42), bolus doses of propofol, 10 mg every 10 seconds, were given until LOC, followed by pancuronium, 0.04 to 0.1 mg/kg, and the remifentanil and propofol infusions were started.

MEASUREMENTS AND MAIN RESULTS

There were no significant differences among the remifentanil dose groups with regard to the primary outcome measure, responses to sternotomy/sternal spread/maximal sternal spread. Responses to these stimuli were recorded in 11%, 11%, and 14% of patients in the remifentanil 1.0, 1.5, and 2.0 microg/kg/min dose groups, respectively. Similarly, there were no significant differences in the responses to other surgical stimuli. There was a high incidence of muscle rigidity when remifentanil was used to induce anesthesia.

CONCLUSIONS

All 3 remifentanil dose regimens provided profound suppression of responses to surgical stimuli in the majority of patients. There was no apparent advantage in starting the remifentanil infusion rate above 1.0 microg/kg/min. Remifentanil is not suitable for use as a sole induction agent.