右美托咪定对女性患者成功置入喉罩时丙泊酚EC50的影响

 目的  研究静注右美托咪定对女性患者成功置入喉罩时所需丙泊酚剂量的影响。 方法  选取择期行妇科宫腔镜检查术患者60例,年龄18~60岁,BMI 18~25 kg/m2,ASA Ⅰ~Ⅱ级,Mallampati Ⅰ~Ⅱ级,随机分为试验组(D组)和对照组(P组),每组30例。试验开始时两组分别恒速静脉输注试验药物10 min,D组试验药物为右美托咪定0.5 μg/kg,P组则为相同容量生理盐水。试验药物输注完毕后5 min,静脉注射芬太尼0.5 μg/kg,并采用效应室靶控输注(target controlled infusion,TCI)丙泊酚,两组丙泊酚初始靶浓度均为3 μg/mL。记录置入喉罩是否成功,根据Dixon序贯法原则决定下一病例的丙泊酚靶浓度(采用等比数据,等比比值1∶0.85),由此计算丙泊酚EC50值。记录输注试验药物前(T0)、试验药物输注完毕后5  min(T1),丙泊酚TCI达靶浓度后喉罩置入前(T2)、成功置入喉罩后1  min(T3)、成功置入喉罩后5  min(T4)的呼吸循环参数和不良反应。 结果  成功置入喉罩时,P组和D组的丙泊酚效应室浓度EC50分别为3.53 μg/mL(95%CI:3.21~3.87 μg/mL)和2.70 μg/mL(95%CI:2.46~2.97 μg/mL ),差异有统计学意义(P<0.01)。P组和D组基础心率血压的差异无统计学意义(T0,P>0.05);靶控输注丙泊酚后,P组较D组血压显著下降(T2,P<0.01;T4,P<0.05);在应用右美托咪定后各时点D组心率均明显低于P组(T1~4,P<0.01)。置入喉罩前后,D组窒息发生率均明显低于P组(置入前:46.67% vs. 83.33%,P<0.01;置入后:13.33% vs. 66.67%,P<0.05)。结论  右美托咪定可显著降低成功置入喉罩时丙泊酚EC50值,并有利于全麻应用喉罩后成功保留自主呼吸。

Effects of dexmedetomidine on EC50 of propofol for successful laryngeal mask insertion in women

Objective  To investigate the effects of dexmedetomidine on propofol dosage for successful laryngeal mask insertion. Methods  Sixty patients aged 18-60 with BMI 18-25 kg/m2, ASA Ⅰ-Ⅱ and Mallampati Ⅰ-Ⅱ undergoing selective hysteroscopic examinations were selected, and were randomly divided into control group (group P) and experiment group (group D), with 30 patients in each group. At the beginning of the study, experimental drugs (dexmedetomidine 0.5 μg/kg in group D; normal saline in group P) were intravenously administrated at a constant velocity for 10 min by an infusion pump in each group. Five minutes later, 0.5 μg/kg fentanyl was intravenously injected, and effect-site concentration target controlled infusion (TCI) of propofol was performed with the initial target effect-site concentration of 3 μg/mL in both groups. The status of laryngeal mask insertion was recorded, and according to the recorded status, the target propofol concentration of the following patient was determined by Dixon’s up-and-down method (ratio 1∶0.85), and then EC50 of propofol was determined. The respiratory and circulatory parameters and adverse reaction at each stage (T0: before applying dexmedetomidine or saline; T1:5 min after applying dexmedetomidine or saline; T2: after TCI of propofol and before LMA insertion; T3:1 min after LMA insertion; T4:5 min after LMA insertion) were recorded and compared. Results  Effect-site EC50 values of propofol for successful laryngeal mask insertion were 3.53 μg/mL (95%CI:3.21-3.87 μg/mL) for group P and 2.70 μg/mL (95%CI:2.46-2.97 μg/mL) for group D (P<0.01). The baseline of SBP and HR in both groups had no significant difference (T0,P>0.05). After TCI of propofol, SBP in group P was significantly lower than that in group D (T2,P<0.01; T4,P<0.05); HR in group D was significantly lower than that in group P at every stage after dexmeditomidine was administered (T1-4,P<0.01).The incidence of apnea in group D was significantly lower than that in group P whether before laryngeal mask insertion (46.67% vs. 83.33%, P<0.01) or after laryngeal mask insertion (13.33% vs. 66.67%,P<0.05). Conclusions  Dexmedetomidine can significantly reduce the EC50 values of propofol for successful laryngeal mask insertion, and may be beneficial to preserve spontaneous breath in general anesthesia with laryngeal mask airway.