右美托咪啶用于腰硬联合麻醉最佳镇静效果与剂量关系的探讨

The Dose-sedation Relationship of Dexmedetomidine during Combined Spinal Epidural Anesthesia

目的比较不同剂量右美托咪定用于腰硬联合麻醉时对患者呼吸、循环、脑电双频谱指数(BIS)的影响,探讨右美托咪定剂量与镇静深度之间的关系。方法腰硬联合麻醉下手术患者115例随机分为三组:A组为右美托咪定负荷剂量+生理盐水持续输注组(对照组,n=39)、B组为右美托咪定负荷剂量+持续输注组(速度0.2μg/kg/h,n=39)、C组为右美托咪啶负荷剂量+持续输注组(速度0.4 g/kg/h,n=37)。记录三组患者右美托咪定负荷剂量给药、持续静脉输注给药及给药后120 min内各个时点SpO2、呼吸频率(RR)、无创血压、心率(HR)、BIS等指标。结果右美托咪定静脉输注60 min,A组、B组、C组BIS值变化无显著差异;70 min、80 min时点A组BIS值显著高于B组与C组;T9、T10、T11、T12时点A组与B组BIS值显著高于C组;TL^T12期间,A组、B组及C组HR、MAP变化无显著统计学差异。结论右美托咪定用于腰硬联合麻醉辅助镇静,1μg/kg的负荷剂量即可产生60min左右的镇静作用;1μg/kg的负荷剂量加0.2μg/kg/h维持可产生90 min左右的镇静作用;1μg/kg的负荷剂量加0.4μg/kg/h维持可以产生约120 min左右的镇静作用。

Objective To investigate the optimal dose of intravenous dexmedetomidine for prop- er sedation in combined spinal epidural anesthesia.Methods One hundred and fifteen patients were randomly assigned to one of the following three groups. After performing the combined spinal epidural anesthesia with hyperbaric bupivacaine（ 12 mg）,a loading dose of dexmedetomi- dine（1 μg/kg） was administered to for 10 minutes, followed by the maintenance infusion of following ： Group A （ n = 39, normal saline）, Group B （ n = 39, dexmedetomidine 0.2 μg/kg/h）, Group C （n = 37, dexmedetomidine 0.4 μg/kg/h）. Heart rate, blood pressure, oxygensaturation, and the bispectral index score（BIS） were recorded during the operation. Results There were no significant differences in mean blood pressure and heart rate among the three groups. BIS was not significantly different among the three groups from baseline to 60 minutes after the infusion of dexmedetomidine. BIS was significantly increased in Group A after 70 and 80 minutes respectively, so did Group A and B after 90,100,110 minutes of dexmedetomidine infu- sion （P〈0.05）.Conclusion The loading dose （1 μg/kg/10min） of dexmedetomidine brought adequate sedation for surgery within 60 minutes. Dexmedetomidine infusion followed by mainte- nance dose （0.2 μg/kg/h） brought adequate sedation for surgery within 90 minutes. Dexme-detomidine infusion followed by maintenance dose （0.4 μg/kg/h） brought adequate sedation for surgery within 120 minutes.