The Effect of Magnesium Infusion in Postoperative Analgesia in Coronary Artery Bypass Graft Surgery

Objectives: It has been shown that patients who have undergone noncardiac surgery experience decreased postoperative pain when given magnesium sulfate (MgSO₄). In this study, we aimed to investigate the effects of MgSO₄ infusion on postoperative pain in coronary artery bypass graft (CABG) surgery.
Methods: After approval from the Ethics Committee and obtaining informed consent, 100 patients undergoing elective CABG, classified as ASA-III and having a preoperative EF above 40%, were selected. The patients were prospectively randomized to group I (n=50), which received MgSO₄ (15 mg–1kg–1h–1), and group II (control) (n=50). Both groups received morphine infusion (0.07 mg–1kg–1h–1) postoperatively via PCA. To evaluate analgesia, pain scores were assessed using VAS immediately after extubation and at 2, 6, and 12 hours. Simultaneously, the number of requests made to the PCA device, the number of requests met, and the total morphine dose were determined and recorded. In the statistical analysis (SPSS), differences between groups were evaluated using Student’s t test and two-way analysis of variance (p<0.05). The results were expressed as mean value±standard deviation.
Results: VAS scores at the 6th and 12th hours after extubation were lower in the magnesium group compared with the control group (p<0.05). The total morphine amount and frequency of PCA use were lower in the magnesium group than in the control group. However, these dif-ferences were not statistically significant.
Conclusion: We suggest that magnesium therapy for postoperative analgesia could be a useful option in CABG surgery.

Keywords: Coronary artery bypass graft surgery, magnesium sulfate, postoperative analgesia