Median effective plasma concentration of remifentanil inhibiting cardiovascular response to tracheal intubation and skin incision when combined with propofol in patients of Uighur nationality

Objective To determine the median effective plasma concentration of remifentanil (EC50) inhibiting cardiovascular response to tracheal intubation and skin incision when combined with propofol in patients of Uighur nationality.Methods Thirty ASA Ⅰ or Ⅱ Uighurs aged 20-60 yr with body mass index of 18-30 kg/m2 undergoing elective laparoscopic cholecystectomy were enrolled in this study.Anesthesia was induced and maintained with propofol infusion.BIS value was maintained at 40-50.TCI of remifentanil was then started.The initial target plasma concentration (Cp) was 6.0 ng/ml.EC50 of remifentanil was determined by modified Dixon' s upand-down sequential experiment.Each time Cp increased/decreased by 0.5 ng/ml.Tracheal intubation was facili.tated with cisatracurium 0.2 mg/kg at 2 min after a new Cp was set when target effect-site concentration (Ce) was balanced with Cp.Positive cardiovascular response was defined as increase in SBP by 15％ and/or HR ＞ 90 bpm lasting＞15 s.The EC50 (95％ confidence interval) of remifentanil blunting responses to tracheal intubation and skin incision was calculated.Results EC50 (95 ％ confidence interval) of remifentanil inhibiting cardiovascular response to tracheal intubation and skin incision when combined with propofol was 3.4 (2.3-4.5) ng/ml and 3.8 (2.8-4.9) ng/ml respectively.Conclusion When depth of anesthesia was maintained at BIS value 40-50 with propofol infusion,the EC50 of remifentanil inhibiting cardiovascular response to tracheal intubation and skin incision is 3.4 and 3.8 ng/ml respectively. Key words: Piperidines; Uygur nationality; Propofol; Dose-response relationship,drug; Drug delivery systems