Evaluation of Analgesic Effect of Magnesium Sulphate in Intravenous Regional Anaesthesia- A Double Blind Study

Abstract

BACKGROUNDMagnesium antagonizes N-Methyl-D-Aspartate receptor, the receptor known to play an important role in the mechanism of pain. This study was undertaken to determine the effect of magnesium sulphate as an adjunct to lignocaine in Intra-Venous Regional Anaesthesia (IVRA). To evaluate the onset of anaesthesia, dose requirement of lignocaine, postoperative analgesia in upper limb surgeries. MATERIALS AND METHODSThis study was designed as a prospective, double blinded, randomised trial consisting of sixty patients. All selected patients were randomly divided into two groups. Saline group (n=30) who received fifteen millilitres of normal saline intravenously and magnesium group (n=30) who received magnesium sulphate 500mg in fifteen millilitre volume intravenously into the limb to be anaesthetised. Five millilitres of 1% lignocaine (preservative free) was administered every fifteen minutes and patients were assessed for loss of sensory and motor power, lignocaine requirement and postoperative analgesia. Data were analysed using Tukey and multivariate test. RESULTSThe mean time required to achieve surgical anaesthesia in magnesium group was 30.67±5.04 min and 53.17±5.65 min in saline group. Total dose of lignocaine required was 73.33±25.3 mg in magnesium group and 160.00±20.34 mg in saline group. Morphine requirement was 2.44±1.00 mg in magnesium group and 5.65±2.04 mg in saline group. Data showed statistically significant difference between the two groups (p=0.00). CONCLUSIONIt was concluded that magnesium as an adjunct fastens the onset of anaesthesia, reduces lignocaine requirement and prolonged postoperative analgesia. However, there was an increased incidence of transient pain with magnesium sulphate.HOW TO CITE THIS ARTICLE: Kumar M, Thabah R. Evaluation of analgesic effect of magnesium sulphate in intravenous regional anaesthesia-a double blind study.