Anaesthesia and critical care department, hôpital Antoine-Béclère, Assistance publique-Hôpitaux de Paris, 157, rue de la Porte-de-Trivaux, BP 405, 92141 Clamart, France.
Anaesthesia and critical care department, Cochin teaching hospital, groupement hospitalier universitaire Ouest, Assistance publique-Hôpitaux de Paris, 27, rue du Faubourg-Saint-Jacques, 75679 Paris cedex 14, France; Paris 05 René-Descartes University, 75006 Paris, France; Inserm, UMR S953, epidemiological research unit on perinatal health and women's and children's health, maternité Port Royal, Cochin teaching hospital, 75014 Paris, France; UMR S953, UPMC Paris 06 university, 75005 Paris, France.
Anaesth Crit Care Pain Med. 2018 Oct;37(5):429-434. doi: 10.1016/j.accpm.2017.12.009. Epub 2017 Dec 30.
A comparison of the effective dose in 50% of patients (ED50) has suggested that the potency of levobupivacaine lies between that of bupivacaine and ropivacaine. However, for clinical purposes, knowledge and use of doses close to the ED95 are more relevant. This study was designed to determine the EC80 (effective concentration) for both epidural levobupivacaine and ropivacaine using the Continual Reassessment Method (CRM) during obstetric analgesia.
In this double-blind randomised study, term parturients were included by cohorts of 6 if cervical dilatation was≤5cm and visual analogue pain score (VAPS)>30mm. Efficacy was defined by a decrease of VAPS to a value≤10, thirty minutes after epidural injection of 20mL of levobupivacaine or ropivacaine. The first cohort received the lowest dose. Every next cohort received a dose according to the response's probability calculated using a Bayesian method, incorporating data from all consecutive previous patients. In addition, a logistic equation was fitted a posteriori to the whole data set to determine the whole dose-probability curve.
Fifty-four patients were enrolled. Levobupivacaine 0.17% and ropivacaine 0.2% gave probabilities of success of 82% and 72% respectively. By fitting the logistic model to the data, the concentration leading to a probability of 0.8 (EC80) was 0.14% for levobupivacaine and 0.24% for ropivacaine while the EC50 were 0.09% for levobupivacaine and 0.17% for ropivacaine, respectively.
This study suggests that epidural levobupivacaine used as the sole drug for labour analgesia has an EC80 lower than that of ropivacaine.
半数患者有效剂量（ED50）的比较表明，左布比卡因的效价介于布比卡因和罗哌卡因之间。然而，对于临床目的，接近 ED95 的剂量的知识和使用更为相关。本研究旨在使用连续评估法（CRM）确定硬膜外左布比卡因和罗哌卡因的 EC80（有效浓度）在产科镇痛期间。
在这项双盲随机研究中，如果宫颈扩张≤5cm且视觉模拟疼痛评分（VAPS）>30mm，则通过 6 例的队列纳入足月产妇。在硬膜外注射 20mL 左布比卡因或罗哌卡因 30 分钟后，通过 VAPS 值降低至≤10 来定义疗效。第一组接受最低剂量。下一组根据使用贝叶斯方法计算的反应概率接受剂量，该方法纳入了所有连续先前患者的数据。此外，还对整个数据集进行了后验拟合逻辑方程，以确定整个剂量-概率曲线。
共纳入 54 例患者。左布比卡因 0.17%和罗哌卡因 0.2%的成功率分别为 82%和 72%。通过将逻辑模型拟合到数据中，概率为 0.8（EC80）的浓度对于左布比卡因为 0.14%，对于罗哌卡因为 0.24%，而 EC50 对于左布比卡因为 0.09%，对于罗哌卡因为 0.17%。
本研究表明，单独用于分娩镇痛的硬膜外左布比卡因的 EC80 低于罗哌卡因。
