Comparison of vital capacity induction with sevoflurane to intravenous induction with propofol for adult ambulatory anesthesia

We compared vital capacity inhaled induction (VC) with sevoflurane with IV induction with propofol for adult ambulatory anesthesia. Patients were randomly assigned to receive either 8% sevoflurane in 75% N2O/O-2 from a primed circuit (VC, 32 patients) or propofol 2-mg/kg bolus (IV, 24 patients). Times to loss of consciousness (response to command) and induction side effects (airway, hemodynamic, motor) were assessed. Anesthesia was maintained with sevoflurane/N2O via a face mask for both groups. At the end of surgery, recovery times were measured and psychomotor function tests were performed. Patients were also asked to assess the quality of their anesthesia. Of the VC patients, 59% lost responsiveness in one breath, taking 39 +/- 3 s. All VC patients completed the induction, and all measures of induction time were significantly shorter for VC than for IV. Induction side effects were different in the two groups (cough and hiccough for VC versus movement and blood pressure changes for IV), but overall incidences were similar. There were no significant differences in any index of early or intermediate recovery. Mild nausea occurred more often with VC, but no antiemetics were needed, and discharge was not delayed. Patients' assessments of the quality of induction or wake up were not significantly different between VC and IV. Thus, VC induction with sevoflurane is an acceptable alternative to propofol IV induction of general anesthesia for adult ambulatory surgical patients. Implications: A vital capacity induction with sevoflurane produced a faster loss of consciousness and had side effects, recovery times, and patient satisfaction similar to that of a propofol induction in adults undergoing ambulatory surgery.