Use of propofol for office-based anesthesia: Effect of nitrous oxide on recovery profile

Study Objective: To evaluate the effect of nitrous oxide (N2O) on the recovery profile and the incidence of postoperative nausea-and vomiting (PONV) after office-based surgery performed under propofol anesthesia. Design: Prospective, randomized, single-blind study. Setting: Office-based surgical center. Patients: 69 ASA physical status I, II, and III healthy, consenting outpatients undergoing superficial surgical procedures' lasting 15 to 45 minutes. Interventions: After a standard propofol induction (1.5 mg . kg(-1) IV), anesthesia was initially maintained with propofol, 100 mu g . kg(-1) . min(-1) IV, in combination with either air or N2O 65% in oxygen. The propofol infusion rate was subsequently varied to maintain an adequate depth of anesthesia. All patients received local anesthetic infiltration pit;or to the surgical incision as well as during the operation. No prophylactic antiemetics were administered Measurements and Main Results: Recovery times and the incidences of PONV were recorded during the first 24 hours after surgery. Early and late recovery variables were similar in the two treatment groups; however, 65% N2O produced a 19% decrease in the propofol maintenance dosage requirement. One patient (3%) experienced nausea prior to discharge in the propofol-N2O group, and two patients (6%) experienced nausea at home in the propofol alone group. None of the patients vomited or received antiemetic medication during the 24 hours postdischarge period. Ninety-seven percent of patients receiving propofol alone and all of the patients in the propofol-N2O group were "very satisfied" with their anesthetic experience. Conclusions: In outpatients undergoing office-based surgical procedures with propofol anesthesia, administration of 65% N2O decreased the anesthetic requirement without increasing PONV. Therefore, use of a propofol-N2O combination may be a cost-effective alternative to propofol alone for office-based anesthesia. (C) 1999 by Elsevier Science Inc.