ABSTRACT
Objective To determine the median effective concentration(EC50)of sevoflurane in?hibiting responses to laryngeal mask airway(LMA)removal in pediatric patients under comprehensive clin?ical conditions. Methods Twenty?six pediatric patients of both sexes, aged 1-5 yr, with body mass index of 15-20 kg∕m2, of American Society of Anesthesiologists physical statusⅠ, scheduled for elective minor surgery, were enrolled in this study. Anesthesia was induced by inhaling 8% sevoflurane and injecting dezocine 0.1 mg∕kg. The LMA painted with Teracainum Plasmagel was inserted. Anesthesia was maintained by sevoflurane inhalation and target?controlled infusion of remifentanil. Remifentanil infusion was stopped at 5 min before the end of surgery. At the end of surgery, the end?tidal concentration of sevoflurane was main?tained at the target concentration for at least 10 min and then the laryngeal mask airway was removed. The end?tidal concentration of sevoflurane was determined by using Dixon′s up?and?down sequential method. The end?tidal concentration of sevoflurane was set at 0.8% in the first pediatric patient. Each time the concen?tration of sevoflurane increased∕decreased by 0.1% in the next pediatric patient according to patient′s re?sponses to LMA removal. Results The EC50of sevoflurane inhibiting responses to LMA removal was 0.59%, and the 95% confidence interval was 0.55%-0.63% in pediatric patients under comprehensive clinical conditions. Conclusion The EC50of sevoflurane inhibiting responses to LMA removal is 0.59% in pediatric patients under comprehensive clinical conditions.