Median effective concentration of remifentanil inhibiting responses to tracheal extubation in patients of Uygur nationality / 中华麻醉学杂志

ABSTRACT

Objective To determine the median effective concentration (EC50) of remifentanil inhibiting responses to tracheal extubation in patients of Uygur nationality.Methods The patients of Uygur nationality,aged 18-60 yr,of ASA physical status Ⅰ or [Ⅱ,scheduled for elective surgery,were enrolled in this study.After the end of surgery,remifentanil was given by target-controlled infusion until tracheal extubation.The initial target plasma concentration (Cp) of remifentanil was 2.0 ng/ml.The response was defined as positive when MAP and/or HR increased by ＞ 15％ of the level at the end of operation and the duration ＞ 15 s during extubation.Each time the target Cp increased/decreased if the cardiovascular response was positive or negative.The ratio between the two successive concentrations was 1.1.The EC50 and 95 ％ confidence interval of remifentanil blunting responses to extubation was calculated by Probit method.Results Twenty-eight patients completed the study.The EC50 and 95 ％ confidence interval of remifentanil required for inhibiting the responses to extubation was 1.75 ng/ml and 1.45-2.01 ng/ml.Conclusion The EC50 of remifentanil inhibiting the responses to tracheal extubation is 1.75 ng/ ml in patients of Uygur nationality.