右美托咪啶对异丙酚靶控输注时瑞芬太尼抑制气管插管反应的半数有效血浆浓度的影响

目的测定预先静脉注射小剂量右美托咪啶时成年患者异丙酚靶控输注(TCI)诱导时瑞芬太尼抑制气管插管反应的半数有效血浆浓度(Cp50)。方法择期全麻手术患者40例,ASAⅠ或Ⅱ级,年龄18～60岁,体质量指数20～30kg/m2,随机分为右美托咪啶组(D组)和对照组(C组)。D组患者首先给予0.4μg/kg右美托咪啶缓慢静脉注射(5min注射完毕),C组患者给予相同方法静脉注射生理盐水;观察10min后开始麻醉诱导。瑞芬太尼TCI 5min后TCI血浆靶浓度为3mg/L的异丙酚,患者意识消失后给予罗库溴铵行气管插管。瑞芬太尼的血浆靶浓度按序贯法确定,相邻血浆靶浓度之间的比率为1.2。结果 TCI血浆靶浓度为3mg/L的异丙酚麻醉诱导时,D组和C组瑞芬太尼抑制气管插管的Cp50分别为2.88μg/L和3.72μg/L,95%的可信区间分别为2.75～3.02μg/L和3.54～3.89μg/L。结论成年患者在TCI血浆靶浓度为3mg/L的异丙酚麻醉诱导时,D组和C组瑞芬太尼抑制气管插管反应的Cp50分别为2.88μg/L和3.72μg/L,右美托咪啶能减少瑞芬太尼抑制气管插管反应的Cp50,这可能与右美托咪啶与瑞芬太尼具有协同作用有关。

Effect of dexmedetomidine on efective target plasma concentrations of remifentanil required to prevent tracheal intubation response in 50% of patients anesthetized with propofol by TCI

Objective To observe the effect of single dose dexmedetomidine on efective target plasma concentrations of remifentanil required to prevent tracheal intubation response in 50% of adult patients(Cp50) anesthetized with propofol by TCI.Methods Forty ASA class I or II patients,aged 18 to 60 years old,with body mass index 20-30 kg/m2 undergoing elective general anesthesia were enrolled in the study.The patients were randomly divided into 2 groups:dexmedetomidine(D) group and control(C) group.Group D received dexmedetomidine 0.4 μg/kg by intravenous injection,and the whole dose was given within 5 minutes,and Group C received equal volume of normal saline as Group D intravenously without dexmedetomidine,observed 10 min before induction of anesthesia.Remifentanil was administered by TCI for 5 min followed by propofol given by TCI at a target plasma concentration of 3 mg/L.When the patients lost consciousness,intravenous rocuronium was given to facilitate tracheal intubation.The ratio of two consecutive target plasma concentration was 1.2.Results The Cp50 of remifentanil in Group D and Group C were 2.88 μg/L and 3.72 μg/L,respectively.The 95% confidence intervals were 2.75-3.02 μg/L and 3.54-3.89 μg/L,respectively.Conclusion The Cp50 values of remifentanil for suppression of tracheal intubation response were 2.88 μg/L and 3.72 μg/L in Group D and Group C respectively.Dexmedetomidine reduce the Cp50 values of remifentanil for suppression of tracheal intubation response.It may involve in the synergetic effect between dexmedetomidine and remifentanil.