Continuous infusion of methohexital and alfentanil hydrochloride for general anesthesia in outpatient third molar surgery

Three anesthetic techniques were compared in this study: 1) Intermittent Brevital boluses supplemented with fentanyl and midazolam all titrated to patient movement, 2) constant infusion of Brevital supplemented with fentanyl and midazolam all delivered in calculated mg/kg doses based on total body weight, and 3) constant infusion of methohexital (Brevital) and alfentanil (Alfenta) supplemented by midazolam (Versed), droperidol, and glycopyrolate (Robinul) delivered in calculated mg/kg doses based on lean body mass. Nitrous oxide was delivered in all cases via nasal mask in a 30% to 50% concentration. The mean total dose of Brevital in group 1 (intermittent Brevital bolus) was 0.17 mg/kg/min (SD = 0.07), group 2 (Brevital infusion) was 0.23 mg/kg/min (SD = 0.06), and group 3 (alfentanil/Brevital infusion) was 0.12 mg/kg/min (SD = 0.07). Mean total dose of alfentanil in group 3 equaled 1.58 mcg/kg/min (SD = 0.73). In group 1, 94% of the patients experienced moderate to severe movement intraoperatively. Twenty-three percent of the patients in group 2, and only 7% of group 3 exhibited moderate to severe movement. Emergence in group 3 averaged 4.5 minutes (SD = 1.6). Three patients (7%) in group 3 had postoperative nausea. Additional subjective findings in group 3 included easier airway maintenance during administration of the anesthetic, lack of unpleasant emergence phenomena such as crying, and prompt readiness for discharge. It was concluded that continuous alfentanil and Brevital infusion satisfied the objectives of safety, stability, predictability, and rapid recovery, while improving operating conditions (less patient movement) when compared with more traditional anesthetic techniques.