Median effective target effect-site concentration of sufentanil when intraoperative wake-up test was successful in patients undergoing scoliosis surgery

Abstract

Objective To determine the median effective target effect-site concentration (EC50) of sufentanil when intraoperative wake-up test was successful in patients undergoing scoliosis surgery.Methods Ninety ASA Ⅰ or Ⅱ patients,aged 18-64 yr,with body mass index ＜ 30 kg/m2,scheduled for scoliosis surgery under sevoflurane and sufentanil anesthesia,were randomly divided into Ⅰ-Ⅵ groups (n =15 each).Anesthesia was induced with sufentanil,etomidate and cisatracurium,and maintained with sevoflurane,sufentanil and cisatracurium.The patients were tracheal intubated and mechanically ventilated.Before the wake-up test,infusion of cisatracurium was stopped and the end-tidal concentration of sevoflurane was adjusted to 0.The EC50 was determined by the K(a)rber method.The target effect-site concentration of sufentanil was set at 0.19 ng/ml in group Ⅰ,0.18 ng/ml in group Ⅱ and gradually decreased in decrements of 0.01 ng/ml.The wake-up test was performed 5 min later.The EC50 and 95 ％ confidence interval of sufentanil were calculated by the K(a)rber method.Results EC50 of sufentanil obtained was 0.164 ng/ml and 95％ confidence interval of sufentanil obtained was 0.157-0.172 ng/ml when the wake-up test was successful.Conclusion The EC50 of sufentanil is 0.164 ng/ml when the intraoperative wake-up test is successful in the patients undergoing scoliosis surgery. Key words: Sufentanil; Drug delivery systems; Dose-response relationship,drug