A multicenter comparison of isoflurane and propofol as adjuncts to remifentanil-based anesthesia

Abstract

Study Objective: To compare recovery, hemodynamics, and side effects of remifentanil-based anesthesia with hypnotic concentrations of isoflurane or propofol. Design: Multicenter, prospective, randomized, two-group study. Setting: 15 university and 5 municipal hospitals. Patients: 249 ASA physical status I, II, and III adult patients scheduled for elective gynecological laparoscopy, varicose vein, or arthroscopic surgery of at least 30 minutes’ duration. Interventions: Anesthesia was induced in the same manner in both groups: remifentanil-bolus (1 μg/kg), start of remifentanil-infusion (0.5 μg/kg/min), followed by propofol as needed for induction. Five minutes after intubation, remifentanil was reduced to 0.25 μg/kg/min, and it was combined with either a propofol-infusion (0.1 mg/kg/min) or with isoflurane (0.6 vol% end-tidal) in O 2/air. Adverse hemodynamic responses of heart rate and systolic blood pressure were recorded and treated according to a predefined protocol. With termination of surgery, anesthetic delivery was discontinued simultaneously without tapering, and recovery times were recorded. Measurements and Main Results: No significant differences were observed between the remifentanil-isoflurane or remifentanil-propofol treatment regimens. Recovery times (means ± SD) were similar for spontaneous ventilation (5.8 ± 3.2 min vs. 6.3 ± 3.7 min), extubation (7.6 ± 3.5 vs. 8.5 ± 4.2 min), eye opening (6.8 ± 3.2 vs. 7.5 ± 3.8 min), and arrival to the postanesthesia care unit (16.5 ± 7.0 vs.18.0 ± 7.2 min). There were no significant differences in adverse hemodynamic responses, postoperative shivering, nausea, or vomiting between the groups. Conclusions: Emergence after remifentanil-based anesthesia with 0.6 vol% of isoflurane is at least as rapid as with 0.1 mg/kg/min propofol. Both isoflurane and propofol are suitable adjuncts to remifentanil, and the applied dosages are clinically equivalent with respect to emergence and recovery. Therefore, both combinations should be appropriate, particularly in settings in which rapid recovery from anesthesia is desirable, such as fast tracking and/or ambulatory surgery.