右美托咪定对不同浓度罗哌卡因腋路臂丛神经阻滞效果的影响

Effects of dexmedetomidine added to different concentrations of ropivacaine for axillary brachial plexus blockade

目的:观察右美托咪定对不同浓度罗哌卡因腋路臂丛神经阻滞效果的影响。方法:选择120例ASA I^II级择期在腋路臂丛神经阻滞下行手部和前臂手术的患者,局麻药依次为A1组(0.3%罗哌卡因)、B1组(0.4%罗哌卡因)、C1组(0.5%罗哌卡因);并分别加入1μg/kg右美托咪定组成对应的A2、B2和C2组。记录感觉和运动神经阻滞的起效时间、阻滞持续时间、阻滞效果和Ramsay镇静评分以及术中循环变化。结果:三个浓度对应的观察组患者的起效时间与单独使用罗哌卡因相比差异无显著性。不同浓度罗哌卡因复合右美托咪定后与单纯使用罗哌卡因相比较(A2与A1,B2与B1,C2与C1),感觉神经阻滞时间均明显延长且差异有统计学意义(P<0.01),而运动神经阻滞持续时间相比较差异无统计学意义。A2组与A1组比较,阻滞效果优的比例明显增加。添加右美托咪定的三个实验组在注入局麻药后60、90、120 min的平均动脉压与对应的对照组比较明显降低(P<0.05),并且这三个实验组在30、60、90、120 min的心率比相应浓度对照组降低且差异有统计学意义(P<0.05)。结论:不同浓度罗哌卡因复合右美托咪定用于腋路臂丛神经阻滞均可以延长感觉神经阻滞时间,但没有延长运动阻滞持续时间,0.3%罗哌卡因复合右美托咪定可以提高阻滞效果。

AIM： To evaluate the effect of dexmedetomidine added to different concentrations of ropivacaine for axillary brachial plexus blockade.METHODS： 120 ASA I or II patients scheduled for elective hand and forearm surgery were randomly divided into 6 groups. All patients received axillary brachial plexus blockade by nerve stimulator. Local anesthetic followed by A1 group（ 0. 3% ropivacaine）,B1 group（ 0. 4% ropivacaine）,C1 group（ 0. 5% ropivacaine）; and 1 μg /kg dexmedetomidine were added into three groups corresponding to the A2, B2, and C2 group. Sensory and motor block onset time,block duration,level of sedation and the changes of hemodynamics were recorded.RESULTS： Onset times and the duration of motor block were similar between four groups. Sensory blockade lasted longer in group A2 and B2 than in group A1 and B1 respectively（ P 〈 0. 01）. The MAP in group A2 and B2 at 60,90,120 minutes were significantly lower than those in group A1 and B1 respectively（ P 〈 0. 05）. Heart rate levels in group A1 and B1 at 30,60,90,120 minutes were significantly lower than those in group A1 and B1 respectively（ P 〈 0. 05）. CONCLUSION： Dexmedetomidine added to different concentrations ropivacaine for axillary brachial plexus block prolongs the duration of sensory block and analgesia but the onset time and the duration of motor block were similar.Adding dexmedetomidine to 0. 3% ropivacaine improve the blocking effect. However,dexmedetomidine may also lead to bradycardia and hypotension.