Effects of Magnesium Versus Neostigmine as adjuvant to Lidocaine in Local Intravenous Anesthesia

Abstract

Intravenous regional anesthesia (IVRA) is one of the safest and most consistent modes of regional anesthesia for short procedures on upper extremity. In spite of this, it has been limited by tourniquet pain, and lack of ability to offer postoperative analgesia. The best intravenous regional anesthesia solution should have the following characteristics: fast onset, low dose of local anesthetic, decreased tourniquet pain, and extended post deflation analgesia. Right now, this may merely be reached by adding adjuncts to local anesthetics with limited accomplishment. Neostigmine is a choline esterase inhibitor whose analgesic effect can be explained by neuronal hyperpolarization and by modulation of nitric oxide pathways . The analgesic effect of magnesium can be explained by being a NMDA receptor antagonist. It has a Ca channel inhibitory effect which proved to have antinociptive effect. Also magnesium is a Nitric Oxide donor that induce vasodilation that protect vascular endothelium from Tourniquet induced ischemia. The aim of this study is to compare the analgesic efficacy of magnesium and neostigmine when added to lidocaine in modified Bier’s block used in hand and wrist surgeries.