Comparison of three techniques on time to awakening, time to orientation and incidence of nausea and vomiting using alfentanil in balanced anesthesia in an outpatient surgical setting

Abstract

Maximizing patient safety and comfort while minimizing adverse sequelae are continuing anesthetic challenges. The purpose of this study was to examine three anesthetic techniques utilizing alfentanil with regard to time to awakening, time to orientation and incidence of nausea and vomiting. Surgical procedures were limited to knee arthroscopy, laparoscopy and dental extractions. Unpremedicated ASA I/II outpatients (n = 74) between the ages of 18 and 59 were randomly assigned to one of three groups: Group I: alfentanil + 67% N2O + 33% O2 Group II: alfentanil + 67% N2O + 33% O2 + droperidol 0.015 mg/kg Group III: alfentanil + 100% O2 + 0.7% isoflurane Anesthesia was induced with alfentanil 40 micrograms/kg, atracurium 0.4 mg/kg, thiamylal 4 mg/kg and 100% O2 and was maintained according to group assignment. The anesthetic was supplemented as clinically indicated with incremental boluses of alfentanil 10 micrograms/kg. Upon completion of surgery, muscle relaxation was reversed with edrophonium 0.75 mg/kg and atropine 0.015 mg/kg. Analyses indicated that the three groups were comparable in terms of potentially confounding variables including gender, race, surgical procedure, age, percent of ideal body weight, case length and dose of alfentanil in micrograms/kg/hr. Time to awakening was significantly shorter in the two N2O groups by approximately 1.5 minutes, as compared to the O2 and isoflurane group (p = .0060). Time to orientation was significantly shorter in the N2O groups by approximately 1.5 minutes also, as compared to the O2 and isoflurane group (p = .0142). The two N2O groups did not differ significantly in either measure. The incidence of vomiting in the postanesthesia recovery room (PARR) indicated a significant difference (p = .0317) among groups with vomiting occurring 45.8% of the time in Group I, 28.8% of the time in Group II and 8% of the time in Group III. Total emetic score (nausea and vomiting) in the PARR indicated a significant difference (p = .03) among groups with symptoms occurring 50% of the time in Group I, 28% of the time in Group II, and 16% of the time in Group III.