右美托咪定静脉注射延长肌间沟臂丛神经阻滞时间的有效剂量：单中心、前瞻性、双盲、随机对照试验
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Effective Dose of Intravenous Dexmedetomidine to Prolong the Analgesic Duration of Interscalene Brachial Plexus Block A Single-Center, Prospective, Double-Blind, Randomized Controlled Trial
背景与目的
研究表明单次肌间沟臂丛神经阻滞（ISBPB）时，静脉注射右美托咪定（DEX）可延长镇痛时间，但其有效剂量尚未明确，本研究旨在探讨右美托咪定静脉注射延长肌间沟臂丛神经阻滞时间的临床有效剂量。
方 法
本研究共纳入拟行肩关节镜手术的患者72名，行经肌间沟入路行臂丛神经阻滞后（0.5%罗哌卡因15ml+1:200000肾上腺素），随机分为四组，每组18名患者：control组（静脉注射生理盐水）、DEX 0.5组（静脉注射右美托咪定0.5ug/kg）、DEX 1.0组（静脉注射右美托咪定1.0ug/kg）、DEX 2.0组（静脉注射右美托咪定2.0ug/kg）。主要指标为阻滞开始到首次感到疼痛的时间。
结 果
所有患者ISBPB均阻滞成功。与其他三组相比，DEX2.0组平均镇痛时间显著延长。与对照组，DEX0.5组，DEX1.0组相比，DEX 2.0术后24小时的吗啡当量明显低于其他三组。三组之间术中低血压的发生率和需要血管活性药治疗的患者数无显著差异。运动阻滞时间、镇静时间、心动过缓的发生率也没有显著差异。
结 论
肩关节镜手术的患者，静脉注射DEX 2.0ug/kg可明显延长ISBPB的镇痛时间，不延长运动阻滞时间，并且可显著减少术后24小时内阿片类药物的使用量。
原始文献摘要
Kang R, Jeong J S, Yoo J C, et al. Effective Dose of Intravenous Dexmedetomidine to Prolong the Analgesic Duration of Interscalene Brachial Plexus Block: A Single-Center, Prospective, Double-Blind, Randomized Controlled Trial.[J]. Reg Anesth Pain Med, 2018, online first:1.
Background and Objectives: Intravenous (IV) dexmedetomidine (DEX) is reported to prolong the analgesic duration after single-shot interscalene brachial plexus block (ISBPB). However, the effective analgesic dose of IV DEX remains undetermined. Therefore, we aimed to elucidate the clinically relevant dose of IV DEX to prolong the analgesic duration of ISBPB.
Methods: Seventy-two patients scheduled for arthroscopic shoulder surgery received ISBPB with 15 mL of 0.5% ropivacaine with 1:200,000 epinephrine and were randomly assigned to 1 of 4 groups (n = 18, each):(1) IV normal saline (control), (2) IV DEX 0.5 μg/kg (DEX 0.5), (3) IV DEX 1.0 μg/kg (DEX 1.0), and (4) IV DEX 2.0 μg/kg (DEX 2.0). The primary outcome was time to the first pain at surgical site.
Results: The median (interquartile range) duration of analgesia was significantly prolonged for the DEX 2.0 (874 minutes [727–1153 minutes]) compared with 656 minutes (590–751 minutes), 703 minutes (644–761 minutes), and 696 minutes (615–814 minutes) for the control, DEX 0.5 and DEX1.0 groups, respectively (P = 0.001, P = 0.008, and P = 0.003, respectively). Postoperative cumulative IV morphine equivalent consumption at 24 hours was significantly lower in the DEX 2.0 compared with the control, DEX0.5 andDEX1.0 groups (P < 0.001, P < 0.001, and P = 0.007, respectively). There were no significant differences in the incidence of intraoperative hypotension and the number of patients who required ephedrine after the pairwise group analysis. Also, there were no significant differences on the durations of motor blockade and sedation and the incidence of bradycardia.
Conclusions: Intravenous DEX at a dose of 2.0 μg/kg significantly increased the duration of ISBPB analgesia without prolonging motor blockade and reduced the cumulative opioid consumption at the first 24 hours in patients undergoing arthroscopic shoulder surgery.
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