Comparison of magnesium sulphate with clonidine and magnesium sulphate alone in terms of motor & sensory blockade as an adjuvant to hyperbaric bupivacaine during spinal anaesthesia- a prospective randomised clinical trial

Abstract

Background- The task of medicine is to preserve, restore health and to relieve pain. Understanding pain is essential to both these goals. This present study was designed to know the motor and sensory blockade when clonidine with MgSO4 was added as an adjunct to bupivacaine.Objectives- To evaluate the Sensory Block: onset, duration, time for maximal sensory block and Motor Block: onset and duration of motor block
Methods- A prospective randomized controlled trial was done in patients posted for elective lower abdominal and lower limb surgeries for 2 years. Two groups were decided Group M (n=35), received 3 ml of 0.5% hyperbaric bupivacaine, preservative free magnesium sulphate 50%, 0.1 ml(50 mg) and preservative free normal saline 0.5 ml. Group CM (n=35), received 3 ml of 0.5% hyperbaric bupivacaine, preservative free magnesium sulphate 50%, 0.1 ml(50 mg) and clonidine 0.5 ml (75µg). SPSS (version 22.0) was used for analysis. Results- In group M, there were 17 males and 18 females, and in group CM there were 18 males and 17 females. The onset of sensory block was faster in group CM compared to group M. By using unpaired t- tests, p-value was <0.0001. The onset of motor block was faster in group CM compared to group M. By using unpaired t- tests, p-value was <0.0001. Conclusion- Based on the present clinical comparative study, we conclude that the combination of clonidine (75µg) and magnesium sulphate (50 mg) as adjuvants with hyperbaric bupivacaine 0.5% (15 mg) for subarachanoid blockade results in earlier onset of action, prolonged duration of sensory blockade and extended postoperative analgesia.
Keywords: Spinal Anaesthesia, Intrathecal Bupivacaine, Sensory blockade, Randomization, Bromage scale, post-operative analgesia.