ED50 of remifentanil needed for tracheal intubation without neuromuscular relaxant in children when combined with sevoflurane inhalation / 中华麻醉学杂志

ABSTRACT

Objective To determine the ED50 of remifentanil needed for tracheal intubation without neuromuscular relaxant in children when combined with sevoflurane inhalation.Methods Twenty-five ASA Ⅰ or Ⅱ children of both sexes,aged 4-9 yr,scheduled for elective surgery under general anesthesia were enrolled in this study.Anesthesia was induced with inhalation of 5% sevoflurane in 100% oxygen and PETCOM2was maintained at 30-35 mm Hg.Remifentanil was injected intravenously over 30 s after 3 min inhalation of sevoflurane.Tracheal intubation was performed 90 s after the completion of remifentanil injection.The experiment was performed using the modified Dixon's up-and-down method.The initial dose of remifentanil was set at 1.2 μg/kg and the ratio between two successive doses was 1.2.Intubation conditions were assessed by a blinded observer using Viby-Mogensen scale.If the conditions were not good,roenronium 0.3 mg/kg was then injected intravenously to facilitate intubation.The ED50 of remifentanil and 95% confidence interval (95% CI) were calculated.Results The ED50 of remifentanil combined with inhalation of scvoflurane required for successful intubation was 0.68 μg/kg in the absence of neuromuscular relaxant,and 95% CI was 0.65-0.71 μg/kg.Conclusion The ED50 of remifentanil required for tracheal intubatiun without neuromuscular relaxant drug is 0.68 μg/kg (95% CI 0.65-0.71 μg/kg) when combined with 5% sevoflurane inhalation in children.