右美托咪定辅助罗哌卡因在硬膜外分娩镇痛中的半数有效浓度呈剂量依赖性降低
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右美托咪定辅助罗哌卡因在硬膜外分娩镇痛中的半数有效浓度呈剂量依赖性降低
翻译：吴学艳 编辑：冯玉蓉 审校：曹莹
研究目的：辅助使用右美托咪啶可降低硬膜外分娩镇痛所需的罗哌卡因浓度，然而，右美托咪啶的药效尚未得到充分证实；本研究目的是确定右美托咪定辅助的罗哌卡因的中位有效浓度（EC50）。
设计：前瞻性、双盲、升降序贯分配研究。
机构：妇幼保健医疗学术中心
病人：最终纳入150例需硬膜外分娩镇痛的健康足月产妇，随机分为5种不同浓度的右美托咪啶组：0μg/ml、0.3μg/ml、0.4μg/ml、0.5μg/ml及0.6μg/ml。
干预措施：每组中第一例患者分娩镇痛所用药物为随机分配的右美托咪啶浓度及0.1%罗哌卡因；每个随机分组的后续患者接受由升降序贯分配方法确定的新浓度罗哌卡因中指定的右美托咪啶浓度。硬膜外分娩镇痛后30min视觉模拟评分小于3被认为是有效镇痛。采用升降序贯分配法和概率回归方法计算硬膜外罗哌卡因的EC50。
测量指标：主要结果是经硬膜外分娩镇痛30分钟后的疼痛评分。探索性结果包括副作用、新生儿结局及产科结局。
主要结果：罗哌卡因在右美托咪定0.4%μ g/ml、0.5% μ g/ml和0.6%μ g/ml中的EC50值分别为0.044%[95%CI 0.036%～0.045%]、0.035%[95%CI 0.031%～0.041%]和0.039%[95%CI 0.034%～0.045%]，EC50值低于罗哌卡因在右美托咪定为0μg/ml和0.3μg/ml(分别为0.086%[95%CI0.081%至0.092%]和0.069%[95%CI0.056%至0.076%])；罗哌卡因在右美托咪啶0.4ug/ml、0.5ug/ml、0.6ug/ml中的EC50值差异无统计学意义(P>0.0 5)；探索性结果分析没有显示副作用、新生儿结局及产科结局无明显差异。
结论：在本研究中，临床效果最好的右美托咪定在罗哌卡因中的最低浓度为0.4ug/ml，当右美托咪定浓度大于0.4ug/ml时，可能没有额外的镇痛效果。
原始文献来源: Liu L, Drzymalski D, Xu W, et al. Dose dependent reduction in median effective concentration (EC) of ropivacaine with adjuvant dexmedetomidine in labor epidural analgesia: An up-down sequential allocation study.[J].J Clin Anesth 2020 Nov 01;68.
Dose dependent reduction in median effective concentration (EC) of ropivacaine with adjuvant dexmedetomidine in labor epidural analgesia: An up-down sequential allocation study
Abstract
Study objective: Adjuvant dexmedetomidine can be used to reduce the required concentration of ropivacaine for labor epidural analgesia. However, the potency of dexmedetomidine has not been fully studied. The purpose of this study was to determine the median effective concentration (EC50) of ropivacaine with adjuvant dexmedetomidine.
Design: Prospective, double-blind, up-down sequential allocation study.
Setting: Academic medical center specializing in the care of women and children.
Patients: One hundred and fifty healthy, term parturients requesting labor epidural analgesia were randomly assigned to 1 of 5 different concentrations of dexmedetomidine: 0 μg/ml, 0.3 μg/ml, 0.4 μg/ml, 0.5 μg/ml, or 0.6 μg/ml.
Interventions: The study solution for the first patient in each group included the randomly assigned concentration of dexmedetomidine in 0.1% ropivacaine. Subsequent patients in each randomization group received the assigned concentration of dexmedetomidine in a new concentration of ropivacaine as determined by the updown allocation methodology. Effective analgesia was defined as pain on the visual analogue scale of<3 at30 min after administration of local anesthetic. The up-down sequential allocation method and probit regression were used to calculate the EC50 of epidural ropivacaine.
Measurements: The primary outcome was pain 30 min after administration of local anesthetic via epidural catheter. Exploratory outcomes included side effects, neonatal outcomes, and obstetric outcomes.
Main results: The EC50 values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml (0.044% [95% CI 0.036% to 0.045%], 0.035% [95% CI 0.031% to 0.041%], and 0.039% [95% CI 0.034% to 0.045%], respectively) were lower compared to ropivacaine in dexmedetomidine 0 μg/ml and 0.3 μg/ml (0.086% [95% CI0.081% to 0.092%], and, 0.069% [95% CI 0.056% to 0.076%], respectively). Differences between EC50 values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml were not statistically significant. Results of our exploratory analyses did not reveal differences in side effects, neonatal outcomes, or obstetric outcomes.
Conclusions: In this study, the lowest concentration of dexmedetomidine in ropivacaine with the greatest clinical effect was 0.4 μg/ml, which is important because there may be no additional analgesic benefit of dexmedetomidine greater than 0.4 μg/ml.
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