Comparison of the efficacy of morphine and magnesium sulphate versus morphine alone to manage pain after coronary artery bypass grafting.

Abstract

Objective: To compare the efficacy of morphine and magnesium sulphate versus morphine alone to manage pain after coronary artery bypass grafting. Study Design: Prospective Cohort Study. Setting: Department of Anesthesiology, CPEIC Multan. Period: June 2025 to December 2025. Methods: Department of Anesthesiology, CPEIC Multan. Methods: Sample size was calculated through OpenEpi online software using formula for cohort study. Where, Efficacy in magnesium sulphate group = 68%, Power of the study = 80%, Efficacy in morphine only group = 17%, Confidence level = 95%, Sample size =60 (30 in each group). Sampling technique was Non-probability consecutive sampling. Inclusion Criteria, Age 35-65 years, either male or female gender, planned to undergo coronary artery bypass grafting. The data was analysed through SPSS version 23. Efficacy between the two groups was compared using chi-square test and p-value ≤ 0.05 was taken as significant. Post stratification chi-square test was applied and p-value ≤ 0.05 was taken as significant. Results: A total of 60 patients were enrolled into the study in equal proportions. Morphine plus Magnesium Sulphate (MM) group had significantly lower mean Visual Analogue Scale (VAS) pain scores at 6, 12 and 24 hours than the Morphine alone (M) group (p <.05 ). The MM group had a much lower requirement to rescue analgesia, and the efficacy was found to be 68% as compared to 17% in the M group (p=0.001). More so, the ICU stay and intubation time were much shorter in the MM. Conclusion: Morphine in combination with magnesium sulphate is more effective than morphine in treatment of postoperative pain following coronary artery bypass grafting. Magnesium sulphate is a safe and cost-effective adjunct to cardiac anesthesia, it substantially decreases opioid use, decreases pain scores, and length of stay in the ICU, indicating magnesium sulphate as a useful option.