七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度

Half-effective target plasma concentration of remifentanil blunting cardiovascular responses to tracheal intubation during sevoflurane anesthesia in children

目的确定七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度（c‰）。方法择期全麻手术患儿，年龄2～5岁，ASAⅠ或Ⅱ级。初始七氟醚吸入浓度为8％，氧流量3L／min，待患儿意识消失后调整七氟醚吸入浓度，使呼气末七氟醚浓度为2．5％（1MAC），2min后采用Minto药代动力学模型靶控输注瑞芬太尼，10min后进行气管插管。瑞芬太尼血浆靶浓度按序贯法确定，瑞芬太尼血浆靶浓度从6pg／L开始，相邻浓度的比值为1．2，气管插管心血管反应的标准：插管后2min内MAP和／或HR较插管前升高≥15％。结果瑞芬太尼抑制气管插管心血管反应的Cp50为3．6μg／L，95％可信区间为3．1～4．0μg/L。结论七氟醚1MAC麻醉下瑞芬太尼抑制小儿气管插管心血管反应的CP50为3.6μg／L，95％可信区间为3.1～4．0μg/L。

Objective To determine the half-effective target plasma concentration （Cp50） of remifentanil blunting cardiovascular responses to tracheal intubation during sevoflurane anesthesia in children. Methods Children ASA Ⅰ or Ⅱ aged 2-5 yr undergoing elective surgery under general anesthesia were enrolled in this study. The initial sevoflurane inhalation concentration was set at 8 % and the fresh gas flow of oxygen was set at 3 L/min. As soon as consciousness disappeared, the sevoflurane concentration was adjusted to 1 MAC with an endtidal concentration of 2.5 % . Two minutes later, remifentanil was administered by target-controlled infusion with the Minto model. Ten minutes later, tracheal intubation was performed. Target plasma concentration of remifentanil was determined by up-and-down sequential trial. The initial target plasma concentration of remifentanil was set at 6 μg/L. The ratio of two successive target plasma concentrations was 1.2. Cardiovascular responses were defined as an increase in MAP and/or HR ≥ 15 % within 2 min after intubation. Results The Cp50 of remifentanil was 3.6 μg/L. The 95% confidence interval was 3.1-4.0 μg/L. Conclusion The Cp50 of remifentanil blunting cardiovascular responses to tracheal intubation is 3.6 μg/L during sevoflurane 1 MAC anesthesia in children and 95% confidence interval is 3.1-4.0 μg/L.