THE EFFECT OF NEOSTIGMINE ADDED TO AXILLARY BRACHIAL PLEXUS BLOCKADE

Abstract

S260 INTRODUCTION: Recently new interest has focused on cholinergic systems that modulate pain perception and transmission. It was shown that central co-administration of the acetylcholineesterase-inhibitor neostigmine to local anesthetics will result in potent analgesia. However, so far the role of neostigmine in peripherally mediated analgesia remains to be defined. Therefore we evaluated the effect of neostigmine added to mepivacaine axillary plexus blockade. METHODS: Following IRB approval, informed consent was obtained from forty patients (ASA I to II) undergoing upper extremity surgery under axillary plexus blockade. These patients were randomized to receive in a double-blind manner either 50 ml mepivacaine and vehicle or 50 ml mepivacaine and 500 mg neostigmine. Visual analog pain scores (VAS), duration of anesthesia and analgesia, first demand of supplementary pain medication and subsequent 24 hour analgesic consumption, motor function and cardiovascular parameters were assessed. RESULTS: Addition of neostigmine revealed no significant differences in cardiovascular parameters, time until onset and recovery of anesthesia or motor function. Postoperative analgesic consumption trended to be lower in the neostigmine group, whereas a significant prolonged postoperative pain relief was observed for this group (see Figure 1). Data are presented as mean +/- SEM. *=p<.05.Figure 1CONCLUSION: The results of this study suggest a peripheral site of analgesic action of theacetylcholineesterase-inhibitor neostigmine.