THE EFFECT OF A SINGLE DOSE OF MAGNESIUM SULPHATE AS AN ADJUVANT TO EPIDURAL BUPIVACAINE FOR INFRAUMBILICAL SURGERIES: A PROSPECTIVE DOUBLE-BLIND, RANDOMIZED CONTROL TRIAL.

Context: Epidural anesthesia provides the advantage of segmental blockade and many adjuvants have been added to shorten the onset of action, improve the quality of analgesia and prolong the duration of analgesia. Magnesium sulphate(MgSO4) by virtue of its anti-iociceptive property has been administered by various routes.

Aim: To assess the effect of MgSO4 on the duration of onset of action of injection bupivacaine for epidural anesthesia in infraumbilical surgeries.

Materials and methods: A prospective, double-blind, randomized control study was conducted in 40 patients. Group M received 15 ml of bupivacaine 0.5% + 1 ml of 50 mg MgSO4 and Group C received 15 ml of bupivacaine 0.5% + 1 ml of normal saline via epidural route. Onset time of the sensory and motor blockade were the primary outcomes studied. Highest level of sensory block, time for two segment regression, hemodynamic parameters, side effects were the secondary parameters.

Results: There was a significant difference between the groups in the mean onset time of sensory blockade at T8, 12.85 ± 2.32 min in Group M and 16.75 ± 1.74 min in Group C. Median level of sensory blockade was comparable. Mean onset time of motor blockade was 13.85 ± 3.28 min in Group M and 23.25 ± 3.35 min in Group C which was clinically and statistically significant. Time for two segment regression of sensory blockade was 95.75 ± 11.84 min in Group M and 55.5 ± 8.57 min in Group C which was significant. Hemodynamic parameters and side effects were comparable.

Conclusion: Magnesium sulphate as an adjuvant provides rapid onset of epidural anesthesia and prolongs the duration of analgesia with minimal side effects.