Department of Regional Practice Anesthesiology, Cleveland Clinic, Lakewood Hospital Department of Anesthesiology, 14519 Detroit Avenue, Lakewood, OH 44107, USA.
Br J Anaesth. 2011 Sep;107(3):446-53. doi: 10.1093/bja/aer159. Epub 2011 Jun 14.
Pain after shoulder surgery is often treated with interscalene nerve blocks. Single-injection blocks are effective, but time-limited. Adjuncts such as dexamethasone may help. We thus tested the hypothesis that adding dexamethasone significantly prolongs the duration of ropivacaine and bupivacaine analgesia and that the magnitude of the effect differs among the two local anaesthetics.
In a double-blinded trial utilizing single-injection interscalene block, patients were randomized to one of four groups: (i) ropivacaine: 0.5% ropivacaine; (ii) bupivacaine: 0.5% bupivacaine; (iii) ropivacaine and steroid: 0.5% ropivacaine mixed with dexamethasone 8 mg; and (iv) bupivacaine and steroid: 0.5% bupivacaine mixed with dexamethasone 8 mg. The primary outcome was time to first analgesic request after post-anaesthesia care unit discharge. The Kaplan-Meier survival density estimation and stratified Cox's proportional hazard regression were used to compare groups.
Dexamethasone significantly prolonged the duration of analgesia of both ropivacaine [median (inter-quartile range) 11.8 (9.7, 13.8) vs 22.2 (18.0, 28.6) h, log-rank P<0.001] and bupivacaine [14.8 (11.8, 18.1) and 22.4 (20.5, 29.3) h, log-rank P<0.001]. Dexamethasone prolonged analgesia more with ropivacaine than bupivacaine (Cox's model interaction term P=0.0029).
Dexamethasone prolongs analgesia from interscalene blocks using ropivacaine or bupivacaine, with the effect being stronger with ropivacaine. However, block duration was longer with plain bupivacaine than ropivacaine. Thus, although dexamethasone prolonged the action of ropivacaine more than that of bupivacaine, the combined effect of dexamethasone and either drug produced nearly the same 22 h of analgesia.
肩部手术后的疼痛通常采用经肌间沟神经阻滞来治疗。单次注射阻滞是有效的，但作用时间有限。辅助药物如地塞米松可能会有所帮助。因此，我们假设在罗哌卡因和布比卡因中加入地塞米松可以显著延长镇痛作用时间，并且这种效果在两种局部麻醉药之间存在差异。
在一项利用单次肌间沟阻滞的双盲试验中，患者被随机分为四组：（i）罗哌卡因：0.5%罗哌卡因；（ii）布比卡因：0.5%布比卡因；（iii）罗哌卡因和类固醇：0.5%罗哌卡因混合 8 毫克地塞米松；和（iv）布比卡因和类固醇：0.5%布比卡因混合 8 毫克地塞米松。主要结局是从麻醉后护理单元出院后首次请求镇痛的时间。采用 Kaplan-Meier 生存密度估计和分层 Cox 比例风险回归来比较组间差异。
地塞米松显著延长了罗哌卡因[中位数（四分位数间距）11.8（9.7，13.8）比 22.2（18.0，28.6）h，对数秩 P<0.001]和布比卡因[14.8（11.8，18.1）和 22.4（20.5，29.3）h，对数秩 P<0.001]的镇痛作用时间。与布比卡因相比，地塞米松延长罗哌卡因的镇痛作用更明显（Cox 模型交互项 P=0.0029）。
地塞米松延长了罗哌卡因或布比卡因经肌间沟阻滞的镇痛作用，其效果在罗哌卡因中更强。然而，布比卡因的阻滞时间比罗哌卡因长。因此，尽管地塞米松延长了罗哌卡因的作用时间超过布比卡因，但地塞米松与两种药物的联合作用产生了几乎相同的 22 小时镇痛效果。
