静脉输注右美托咪定对臂丛阻滞效果的随机对照研究

目的：探讨不同剂量右美托咪定对肩关节镜手术臂丛神经阻滞效果的影响。方法：90例择期行肩关节镜手术患者采用随机数字表法随机分为3组，分别为R组（对照组）、D1组［静脉输注右美托咪定0.2 μg/(kg·h)］和D2组［静脉输注右美托咪定0.7 μg/(kg·h)］，每组30例。超声引导下行肌间沟臂丛阻滞，注入0.375%（体积分数）罗哌卡因10 mL，评价臂丛阻滞效果后进行全身麻醉。D1组和D2组先静脉输注右美托咪定1.0 μg/kg，10 min内泵注完毕后分别以0.2 μg/(kg·h)、0.7 μg/(kg·h)持续泵注至手术结束前半小时停药。记录各组臂丛阻滞的镇痛持续时间、感觉阻滞持续时间、术后首次疼痛时视觉模拟评分（visual analogue score，VAS）、24 h内补救镇痛次数，同时记录各组给予右美托咪定前（T0）、给药后10 min（T1）、给药后30 min（T2）、停药时（T3）、术毕时（T4）及气管拔管时（T5）的血压和心率。结果：与R组相比，D1组和D2组的镇痛持续时间和感觉阻滞持续时间显著延长（P<0.01），但D1和D2组之间差异无统计学意义（P>0.05）；D1组和D2组的T1~T5各时点的心率、收缩压明显降低（P<0.01）。与D1组比较，D2组低血压和心动过缓的发生率差异有统计学意义（P<0.05）。结论：静脉应用右美托咪定可延长臂丛阻滞的镇痛时间和感觉阻滞时间，有效抑制术中应激反应，为肩关节镜手术患者提供良好的镇痛，其中，小剂量右美托咪定安全性更高，临床效应更佳。

Effect of dexmedetomidine on supraclavicular brachial plexus block: a randomized double blind prospective study

Objective： To evaluate the effect of dexmedetomidine combined with ropivacaine on bra-chial plexus block in patients scheduled for elective shoulder arthroscopy. Methods: Ninety patients with American Society of Anesthesiologists (ASA) ⅠorⅡ, scheduled for elective shoulder arthroscopy, were randomly divided into three groups. In group R (n=30), the patients were given 10 mL of 0.375% ropivacaine in branchial plexus block (interscalene approach guided by ultrasound), in group D1 (n=30), the patients were given 10 mL of 0.375% ropivacaine (interscalene approach guided by ultrasound)+dexmedetomidine 0.2 μg/(kg·h) (intravenous pump infusion), and in group D2 (n=30), the patients were given 10 mL of 0.375% ropivacaine (interscalene approach guided by ultrasound)+dexedetomidine 0.7 μg/(kg·h) (intravenous pump infusion). To evaluate the effect of brachial plexus block before general anesthesia. Group D1 and group D2 were given dexmedetomidine intravenously for 1.0 μg/kg during 10 min, then the drug was pumped by 0.2 μg/(kg·h) and 0.7 μg/(kg·h) respectively until 30 min before the operation finished. Changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and before anesthesia (T0), 10 min (T1), 30 min (T2) after giving dexmedetomidine, discontinue medication (T3), after operation (T4), and extubation (T5) were investigated. Motor and sensory block onset times, block durations, and duration of analgesia were recorded. The scores of pain after operation and the adverse effects of shiver, hypopiesia, drowsiness, and blood loss were recorded during operation. Results: Compared with group R, the duration of analgesia and duration of sensory block in group D1 and group D2 were significant longer (P<0.01), there was no significant difference between groups D1 and D2 (P>0.05). Compared with group R, at each time point of T1-T5, the heart rate and systolic blood pressure in group D1 and group D2 were significantly decreased (P<0.01). Compared with D1 group, the incidence of hypotension and bradycardia in group D2 were significantly different (P<0.05). Conclusion: Intravenous dexmedetomidine could prolong the duration of analgesia time and sensory block within the brachial plexus block, inhibiting the stress response during arthroscopic shoulder surgery. Compared with high-dose, low-dose can provide safer and better clinical effect and reduce the adverse effects of dexmedetomidine.