A comparative study of magnesium sulphate v/s clonidine as adjuvants to intrathecal hyperbaric bupivacaine under spinal anaesthesia for infraumbilical surgeries

Abstract

Introduction: Spinal anaesthesia is the most common technique of regional anaesthesia used for lower abdominal and lower limb surgeries. Local anaesthetic Bupivacaine is the commonly administered drug. Many adjuvants to local anaesthetic have been used for intraoperative as well as post-operative period. In this study magnesium sulphate and alfa 2 adrenergic agonist Clonidine are used as adjuvant to hyperbaric bupivacaine. In this study we evaluate and compare the characteristics of spinal block and side effects in patients undergoing infraumbilical surgeries who received a subarachnoid block with either bupivacaine with magnesium sulphate or with clonidine. Methods: 90 patients of ASA I/II physical status undergoing elective infraumbilical surgeries were randomised into 2 groups. Group M (n=45) patients received 2.5ml of 0.5%bupivacaine with 30mg magnesium sulphate and Group C (n=45) patients received 2.5ml of 0.5% bupivacaine with 30mcg Clonidine. In both group, final drug volume made equal to 3ml by adding normal saline. Quality of block in terms of Time of Onset and total Duration of Sensory and Motor Blockade, 2 Segment regression time, Total analgesia time, Hemodynamic parameters and any Side Effects were recorded. Results: Demographic data were comparable. The mean time of Duration of Sensory Blockade in group M was 130.78±5.95 and in group C 165.02±12.72 (p value <0.001), mean time of 2 segment regression in group M was 103.44±8.01 and in group C 122.49±9.76 (p value <0.001), mean time of duration of motor blockade in group M is 144±6.78, in group C 208.27±21.39 (P value <0.001). Mean time onset of sensory block in group M was 9.44±0.69, in group C 5.85±0.32 (p value <0.001) were statistically significant. Hemodynamic parameters were comparable between the groups except at few intervals. Group C showed significant sensory and motor blockade and delayed requirement of rescue analgesia compared to group M. Conclusion: Intrathecal clonidine as adjuvant is better than intrathecal magnesium sulphate as it prolongs sensory and motor block with no significant haemodynamic variations and side affect.