A comparison between vital capacity induction and tidal breathing induction techniques for the induction of anesthesia and compound A production

Background Vital capacity induction and tidal breathing induction are currently administered for inhalation induction ofanesthesia 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.Methods Fifty-one women with American Society of Anesthesiologists physical status Ⅰ-Ⅱ undergoing mammary glandtumorectomy 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 weremonitored at one-minute intervals after sevoflurane administration.Results The time to loss of eyelash reflex was significantly shorter with the vital capacity induction technique than withthe 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 vitalcapacity 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 vitalcapacity group than those in the tidal breathing group (P <0.05);compound A concentration at the beginning ofanesthesia maintenance was (40.73±10.83) ppm in the vital capacity group and (29.45±7.51) ppm in tidal breathinggroup (P=0.019).Conclusion For inhalation induction of anesthesia,the vital capacity induction was faster and produced fewercomplications than that for tidal breathing induction,but increased compound A production in the circuit system.