BACKGROUNDVital capacity induction and tidal breathing induction are currently administered for inhalation induction of anesthesia with sevoflurane. The aim of this study was to compare them using sevoflurane with respect to induction time, complications of inhalation induction, and compound A production in adult patients.

METHODSFifty-one women with American Society of Anesthesiologists physical status I-II undergoing mammary gland tumorectomy were randomly assigned to receive either vital capacity induction or tidal breathing induction with 8% sevoflurane at 6 L/min followed by laryngeal mask airway insertion. Induction times, complications of inhalation induction, and vital signs were recorded. Inspired concentrations of compound A were assayed and sofnolime temperatures were monitored at one-minute intervals after sevoflurane administration.

RESULTSThe time to loss of eyelash reflex was significantly shorter with the vital capacity induction technique than with the tidal breathing induction technique ((43.8 ± 13.4) seconds vs. (70.8 ± 16.4) seconds, respectively; P < 0.01). Cardiovascular stability was similar in both groups. The incidence of complications was significantly less with the vital capacity induction technique than with the tidal breathing induction technique (7.7% vs. 32%, respectively; P < 0.01). However, the mean and maximum concentrations of compound A during induction were significantly higher in the vital capacity group than those in the tidal breathing group (P < 0.05); compound A concentration at the beginning of anesthesia maintenance was (40.73 ± 10.83) ppm in the vital capacity group and (29.45 ± 7.51) ppm in tidal breathing group (P = 0.019).

CONCLUSIONFor inhalation induction of anesthesia, the vital capacity induction was faster and produced fewer complications than that for tidal breathing induction, but increased compound A production in the circuit system.