Effect of magnesium sulphate on total anaesthetic requirements and postoperative analgesia in craniotomy patients: a prospective randomized interventional study

Abstract Background Post craniotomy, pain management can often be inadequate and that can increase the risk of post op complications and lengthens the recovery time. This study evaluates the impact of magnesium sulphate on overall anaesthetic requirements during surgery, postoperative pain score and analgesic needs of patients undergoing craniotomy. Methods Study included 74 patients planned for craniotomy, divided into the study group MS ( n = 37) and control group C ( n = 37). Same anaesthetic technique was applied to all patients. In group MS, MgSO4 was administered intravenously as a bolus dose of 30 mg/kg over 10 min, followed by a maintenance dose of 10 mg/kg/hr IV until Dural closure. Group C received the same except 0.9% NaCl instead of MgSO4. Pain intensity (the primary objective) was assessed using a visual analogue scale (VAS) every 2 h for the first 8 h, then every 4 h up to 24 h. If the VAS score > 3, tramadol was used 7 . Total rescue analgesic consumption was measured in both groups postoperatively within 24 h (the secondary objective). Results The study group (MS) although demographically similar, consistently demonstrated lower VAS scores compared to the control group (C), with statistically significant differences noted at each time point ( p < 0.05). The analgesia required over 24 h was significantly less in group MS (32.43 ± 24 mg) compared to group C (79.7 ± 36 mg) ( p < 0.001). The first rescue analgesia was needed after 2.03 ± 2.0 h in group MS and after 0.86 ± 0.34 h in group C ( p < 0.001). Conclusion: MgSO4 infusion resulted in lower VAS Score, an increased time before the first rescue analgesic requirement, a reduced total dose of rescue analgesic required in the first 24 h postoperatively, and an improved postoperative pain profile.