Relative analgesic potencies of bupivacaine, ropivacaine and levobupivacaine for caudal analgesia in children
Caudal analgesia, Pediatric, ropivacaine, levobupivacaine, bupivacaine
Published online: Mar 29 2019
Abstract
Background : Caudal epidural analgesia (CEA) is used in children undergoing lower abdominal surgery. Although ropivacaine, levobupivacaine and bupivacaine are commonly used, their relative potency remains poorly defined in case of CEA. The aim of this prospective, randomized, double-blind trial was to determine the minimum local analgesic concentration (MLAC) for each of these three molecules.
Material and methods : Ninety-two children (between 1-8 years old) scheduled for lower abdominal surgery under sevoflurane anesthesia were included and randomized to receive CEA with ropivacaïne, levobupivacaine or bupivacaine. One mL Kg-1 of the “study solution” was injected in the epidural space. Skin incision was allowed 15 minutes after injection. Movements and hemodynamic variability (“clinical response”) associated with skin incision were used to determine the efficacy of the CEA. In all groups, the starting local anesthetic concentration was 0.16% and subsequent concentrations were determined by the clinical response of the previous patient to skin incision using the Dixon’s up-and-down sequential allocation. Increments and decrements were 0.02% for each drug. Secondary endpoints were duration of analgesia, incidence of motor block and side effects (postoperative nausea and vomiting, agitation, urinary retention). Isotonic regression method was used to calculate efficient dose in 50% of patients (ED 50) and in 95% of patients (ED 95).
Results : From the 92 randomized children, 87 were finally included in the protocol. Demographic characteristics were not different between groups. The ED 50 and ED 95 for bupivacaine, ropivacaine and levobupivacaine were, respectively: 0.122% and 0.179%, 0.111% and 0.176%, 0.171% and 0.216%. No difference was observed between the 3 groups in term of efficacy, duration of analgesia, muscular blockade, agitation, and postoperative nausea and vomiting.
Conclusions : In the conditions of our study, MLAC of ropivacaine, and bupivacaine were comparable, much lower than that of levobupivacaine.
