Efficacy of Magnesium Sulfate as an Adjuvant to Bupivacaine in Transversus Abdominis Plane Block for Abdominal Hysterectomy Surgeries

Background Major abdominal surgeries are often accompanied by excruciating pain, which, if not adequately managed, can reduce patient comfort and satisfaction, delay mobilization, compromise respiratory and cardiac functioning, and increase healthcare costs. The transversus abdominis plane (TAP) block is an efficient and safe complement to multimodal postoperative analgesia for abdominal surgery. This study evaluates the efficacy of combining magnesium sulfate (MgSO(4)) with bupivacaine for TAP block in patients posted for total abdominal hysterectomy (TAH). Methodology Seventy female patients between the ages of 35 and 60 who were scheduled to have a TAH under spinal anesthesia were divided randomly into two groups of 35 each: group Bupivacaine (B) and group Bupivacaine-Magnesium sulfate (BM). Group B received 18 milliliters (mL) of bupivacaine 0.25 percentage (%) 45 milligrams (mg) with 2 mL normal saline (NS) whereas group BM received 18 mL of bupivacaine 0.25% (45 mg) with 1.5 mL of 10% weight/volume (w/v) MgSO(4) (150 mg) and 0.5 mL NS in the ultrasonography-guided (USG) bilateral TAP block performed after the end of surgery. Groups were compared for the postoperative visual analog scale (VAS) scores, the time required for first rescue analgesia, the number of analgesic rescues at various time intervals, patient satisfaction score, and any side effects. Results Postoperative VAS scores at 4, 6, 12 and 24th hour (hr) (p < 0.05) in group BM were lower compared to group B. Time required for rescue analgesia was significantly prolonged in group BM (882.94 ± 70.22 minutes) compared to group B (459 ± 100.53 minutes) with minimal usage of rescue analgesia (p < 0.05) up to 12 hr. In group BM, the patient satisfaction score was higher (p = 0.001). Conclusion In addition to a considerable reduction in post operative VAS scores and overall use of rescue analgesia, the addition of magnesium to bupivacaine significantly prolongs the TAP block and increases the initial postoperative period of bearable pain.