We designed a prospective, randomized, multicenter study to compare anesthetic requirements, recovery times, and postoperative side effects when a laryngeal mask airway (LMA) was used as an alternative to the tracheal tube (TT) during ambulatory anesthesia. After induction of anesthesia with midazolam 2 mg, fentanyl 1 microg/kg, and propofol 2 mg/kg, 381 patients were randomly assigned to receive either an LMA (n = 207) or TT (n = 174) for airway management. In patients assigned to the TT group, succinylcholine 1 mg/kg or a nondepolarizing muscle relaxant was administered to facilitate tracheal intubation. Anesthesia was maintained with volatile anesthetics in combination with nitrous oxide 60% and oxygen. The average time to placement of the two airway devices (5 min) and the failure rates (1%) were similar in the two groups. Although there was a significant decrease in the intraoperative fentanyl requirement in the LMA group, the difference was of little clinical significance. Furthermore, there were no differences in the volatile anesthetic requirements. The time from end of surgery to removal of the airway device (5 min) was also similar in the two study groups. Although duration of the postanesthesia care unit stay and time to ambulation were significantly shorter in the LMA group, there were no differences in the times to "home readiness." The incidence of nausea and vomiting and the need for rescue antiemetic treatments in the postoperative period were similar in the two airway management groups. However, the incidence of postoperative sore throat was significantly greater in patients receiving the TT (versus the LMA). In conclusion, this study suggests that the LMA is a useful alternative to the TT for airway management during ambulatory anesthesia.
Implications: Use of the laryngeal mask airway can obviate the need for insertion of a tracheal tube for many ambulatory surgery procedures, and thereby decrease the incidence of postoperative sore throats.