依托咪酯乳剂诱导时雷米芬太尼抑制气管插管反应的效应室靶浓度

Effect-site concentration of remifentanil blunting tracheal intubation response during anesthesia induction with etomidate

目的测定依托咪酯乳剂诱导时雷米芬太尼抑制气管插管反应的效应室靶浓度(EC50和EC95)。方法选择23例ASAⅠ或Ⅱ级全麻择期手术患者靶控输注(TCI)雷米芬太尼,血浆浓度与效应室浓度达到平衡后静脉注射依托咪酯乳剂0.3mg/kg,患者意识消失后静脉注射琥珀胆碱行气管插管。气管插管后2min内最高的SBP和/或HR高出基础值15%为气管插管反应阳性。雷米芬太尼靶浓度按改良序贯法增加或减少0.5ng/ml。用概率单位回归分析法计算出雷米芬太尼抑制气管插管反应的EC50、EC95及相应的95%可信区间(CI)。结果雷米芬太尼抑制气管插管反应的EC50为3.06ng/ml,95%CI为2.56～3.47ng/ml;相应的EC95为3.85ng/ml,95%CI为3.45～6.64ng/ml。结论复合依托咪酯0.3mg/kg诱导时雷米芬太尼抑制气管插管反应的EC50和EC95分别为3.06ng/ml和3.85ng/ml。

Objective To determine the effect-sit concentration of remifentanil blunting tracheal intfibation response in 50% and 95% of patients （EC50 and EC95 ） during anesthesia induction with etomidate. Methods Twenty-three ASA Ⅰ or Ⅱ patients, aged 27-62 years old, body weight index 19-26 kg/m^2 , undergoing selective surgery under general anesthesia were enrolled in this study. Non- invasive BP, HR, ECG, SpO2 and PETCO2 were continuously monitored before and during anesthesia. Intubation response was defined as an increase in SBP and/or HR by 15% of baseline within 2 min after intubation. All patients received target controlled infusion （TCI） of remifentanil. After equilibrium between the plasma and effect-site concentration of remifentanil, etomidate 0. 3 mg/kg was administered intravenously. After loss of consciousness intravenous succinylcholine 1-1.5 mg/kg was given to facilitate tracheal intubation, which was accomplished within 30 seconds. The target concentration of remifentanil for consecutive patients was determined using the modified Dixon＇ s up- and-down method by the intubation response of the previous patient, in an increment or decrement of 0. 5 ng/ml. Probit analysis was used for calculating EC50, EC95 and 95% confidence interval （CI）. Results The EC50 of remifentanil was 3.06 ng/ml （95%CI was 2.56-3.47 ng/ml） and EC4s of remifentanil was 3. 85 ng/ml （95 % CI was 3.45- 6.64 ng/ml）. Conclusion The EC50 and EC95 of remifentanil for suppression of cardiovascular response to tracheal intubation was 3.06 ng/ml and 3. 85 ng/ml, respectively in the patients anesthetized with etomidate.