Comparative Study of Magnesium Sulphate versus Dexmedetomidine as an Adjuvant to Epidural BupivacaineA Randomised Controlled Trial

Abstract

Introduction: Neuraxial adjuvants are used to improve or extend analgesia. They have been utilised in several trials to prolong postoperative analgesia along with spinal anaesthesia, but as epidural anaesthesia is more haemodynamically stable, adding adjuvants to the above will have substantially less detrimental effects. Dexmedetomidine and magnesium sulphate may be used as adjuvants in neuraxial anaesthesia along with local anaesthetics. Aim: To determine the impact of adding magnesium and dexmedetomidine in the lower limb and lower abdominal procedures as an adjuvant to epidural bupivacaine. Materials and Methods: This randomised, single blinded study was conducted on 90 ASA (American Society of Anaesthesiologists) class I and II patients in the Department of Anesthesiology Government Medical college, Kannur, Kerela from September 2015 to September 2016. Following randomisation using the lottery approach, the patients were divided into groups M, D, and C, and given the appropriate drugs through the epidural route. Group D: Bupivacaine 0.5% 10 mL+Dexmedetomidine 0.5 mcg/kg (in 1 mL 0.9% saline); group C: Bupivacaine 0.5% 10 mL+Saline 0.9% (1 mL); group M: Bupivacaine 0.5% 10 mL+MgSO4 50 mg (in 1 mL 0.9% saline). Monitoring was done for the onset, duration, haemodynamic parameters, level of motor and sensory block attained and any adverse outcomes. Data were collected, and statistical analysis was done by Statistical Package for Social Science (SPSS) version 17.0 and Analysis of Variance (ANOVA) with repeated measurements and the contingency coefficient test were both used. Results: Group D had greater postoperative analgesia (307.3±77.3 minutes), while the duration for the onset of sensory (13.1±1.3 minutes) and motor blockade was much shorter. Prolonged motor block and sedation, Ramsay sedation score>3 was observed in Group D. Conclusion: The addition of dexmedetomidine to epidural bupivacaine may be beneficial in the context of the prolonged duration of motor and sensory blockade and arousable sedation.