Elia Nadia, Culebras Xavier, Mazza Christian, Schiffer Eduardo, Tramèr Martin R
Division of Anesthesiology, University Hospitals of Geneva, Geneva.
Reg Anesth Pain Med. 2008 Mar-Apr;33(2):159-67. doi: 10.1016/j.rapm.2007.10.008.
Clonidine is added to intrathecal local anesthetics to improve intraoperative analgesia and to increase the duration of sensory and motor block. The aim of this systematic review is to quantify beneficial and harmful effects of clonidine when used as an adjuvant to intrathecal local anesthetics for surgery.
We included data from 22 randomized trials (1,445 patients) testing a large variety of doses of clonidine, added to intrathecal bupivacaine, mepivacaine, prilocaine, or tetracaine.
Clonidine 15 to 150 microg prolonged in a linear, dose-dependent manner, the time to 2 segment regression (range of means, 14 to 75 minutes) and the time to regression to L2 (range of means, 11 to 128 minutes). The time to first analgesic request (median 101 minutes, range 35 to 310) and of motor block (median 47 minutes, range 6 to 131) was prolonged without evidence of dose-responsiveness. Time to achieve complete sensory or motor block, and extent of cephalic spread remained unchanged. There were fewer episodes of intraoperative pain with clonidine (relative risk, 0.24; 95% confidence interval [CI], 0.09-0.64; number needed to treat, 13) but more episodes of arterial hypotension (relative risk, 1.81; 95% CI 1.44-2.28; number needed to harm, 8) without evidence of dose-responsiveness. The risk of bradycardia was unchanged.
This study may serve as a rational basis to help clinicians decide whether or not to combine clonidine with an intrathecal local anesthetic for surgery. The optimal dose of clonidine, however, remains unknown.
可乐定被添加到鞘内局部麻醉药中以改善术中镇痛并延长感觉和运动阻滞的持续时间。本系统评价的目的是量化可乐定作为鞘内局部麻醉药辅助剂用于手术时的有益和有害作用。
我们纳入了22项随机试验（1445例患者）的数据，这些试验测试了添加到鞘内布比卡因、甲哌卡因、丙胺卡因或丁卡因中的多种剂量可乐定。
15至150微克的可乐定以线性、剂量依赖性方式延长了至2节段消退的时间（均值范围为14至75分钟）和至L2消退的时间（均值范围为11至128分钟）。首次镇痛需求时间（中位数101分钟，范围35至310）和运动阻滞时间（中位数47分钟，范围6至131）延长，且无剂量反应性证据。达到完全感觉或运动阻滞的时间以及头端扩散程度保持不变。可乐定组术中疼痛发作较少（相对危险度，0.24；95%置信区间[CI]，0.09 - 0.64；需治疗人数，13），但动脉低血压发作较多（相对危险度，1.81；95%CI 1.44 - 2.28；需伤害人数，8），且无剂量反应性证据。心动过缓风险未变。
本研究可为临床医生决定是否将可乐定与鞘内局部麻醉药联合用于手术提供合理依据。然而，可乐定的最佳剂量仍未知。
