Effects of Adding Intrathecal Magnesium Sulphate To Bupivacaine And Fentanyl in Lower Abdominal And Lower Limb Surgeries

Background & Aim: Addition of opiates with nonopioid adjuvants to local anaesthetics is becoming popular in perioperative pain management, as no single agent has yet been identified to specifically inhibit nociception without the usual side effects. Research continues concerning different techniques and drugs that could provide optimal operative conditions and postoperative pain relief. The present study is designed to assess the effectiveness of adding magnesium to a combination of intrathecal bupivacaine and fentanyl. Methods: After obtaining informed consent, sixty patients randomized into two groups, thirty each. Study group received 0.5% hyperbaric bupivacaine 2.5ml+ 25mcg (0.5ml) fentanyl + 50mg (1ml) magnesium sulphate. Control group received 0.5% hyperbaric bupivacaine 2.5ml+ 25mcg (0.5ml) fentanyl + 1ml of preservative free 0.9% sodium chloride. Time of onset of sensory, motor block, maximum level of sensory block, time to attain the same, duration of analgesia, two segment regression time, time for complete motor recovery, haemodynamic parameters and perioperative complications studied. All the statistical methods were carried out through the SPSS for Windows (version 16.0). Descriptive statistics, frequencies, crosstabs, independent sample ttest and repeated measures ANOVA were the statistical methods used for this study. Results: Duration of analgesia, time for two segment regression & time for complete motor recovery is significantly longer in MgSO4 group than in control group. Onset time for sensory and motor blockade is delayed in MgSO4 group but is statistically non-significant. Conclusion: Addition of intrathecal magnesium provides longer duration of analgesia, longer time for two segment regression & delays time for complete motor recovery with no significant haemodynamic variations/side effects.