右旋美托咪啶对丙泊酚靶控输注患者呼吸抑制半数有效浓度的影响

Effect of dexmedetomidine on the EC50 of propofol target-controlled infusion for respiratory depression

目的研究右旋美托咪啶对丙泊酚靶控输注(TCI)时患者呼吸抑制的半数有效浓度(EC50)的影响。方法 ASAⅠ或Ⅱ级择期全麻手术患者49例,随机分为右旋美托咪啶组(D组)25例和对照组(C组)24例,分别静脉注射右旋美托咪啶0.4μg/kg或生理盐水5ml,10min后开启丙泊酚TCI泵。分别于麻醉前(T1)、输注右旋美托咪啶或生理盐水后1min(T2)、5min(T3)和10min(T4)及丙泊酚TCI启动后1min(T5)、5min(T6)、结束时(T7)记录VT、分钟通气量(MV)、PETCO2、RR、SBP、DBP、ECG、HR、SpO2、脑电双频谱指数(BIS)和警觉/镇静(OAA/S)评分,计算并比较D、C组丙泊酚TCI所致患者呼吸抑制的EC50及镇静程度。结果 D、C组丙泊酚TCI呼吸抑制的EC50分别为2.35μg/ml(95%可信区间为2.31～2.39μg/ml)和2.62μg/ml(95%可信区间为2.52～2.72μg/ml),D组低于C组(P<0.05);T3～T7时D组患者的BIS值及T5～T7时OAA/S评分明显低于C组(P<0.05)。结论丙泊酚TCI前单次静脉注射0.4μg/kg的右旋美托咪啶能降低丙泊酚TCI患者呼吸抑制的EC50,患者的镇静程度加深。

Objective To determine the effect of systemic dexmedetomidine on the median effective concentration （EC50）of propofol target-controlled infusion （TCI）for respiratory depression. Methods Forty-nine ASA Ⅰor Ⅱpatients,scheduled for elective surgery were randomly allocated to receive dexmedetomidine （group D） and sodium chloride （group C）.Twenty-five patients in group D received intravenous infusion of 0.4 μg/kg dexmedetomidine and twenty-four patients in group C received intravenous infusion of 5 ml normal saline for 5 minutes. 10 minutes later propofol TCI was administrated. BIS,HR,SBP,DBP,ECG,VT,MV,PETCO2,RR,SpO2 and OAA/S were recorded before drug anesthesia （T1）,1min（T2）,5 min（T3） and 10 min（T4）after dexmedetomidine infusion and 1min（T5）,5 min（T6） after propofol TCI and termination of the study（T7）. The EC50 and confidence interval was calculated.Results EC50 of propofol TCI for respiratory depression was 2.35 μg/ml （95% confidence interval was 2.31-2.39 μg/ml） in group D and 2.62 μg/ml （95% confidence interval was 2.51-2.72 μg/ml） in group C. The EC50 of propofol TCI for respiratory depression in group D was lower than that in group C（P0.05）. The BIS values and OAA/S for patients in group D were lower than those in group C（P0.05）.Conclusion 0.4 μg/kg dexmedetomidine administration before propofol target-controlled infusion could decrease the propofol EC50 for respiratory depression,and increase the depth of sedation.