# Postoperative Analgesic Effect of Bupivacaine and Magnesium Sulphate vs. Bupivacaine and Dexmedetomidine in Transversus Abdominis Plane Block

## TL;DR

This study compares the analgesic effects of magnesium sulphate and dexmedetomidine when added to bupivacaine in TAP blocks for laparoscopic surgery patients.

## Contribution

The study provides a direct comparison of magnesium sulphate and dexmedetomidine as adjuvants in TAP blocks, focusing on analgesic duration and safety.

## Key findings

- Magnesium sulphate prolonged postoperative analgesia by 1 hour compared to dexmedetomidine.
- Total analgesic use was lower in the magnesium group, with no significant difference in pain scores.
- Both groups had stable hemodynamics and similar adverse event rates.

## Abstract

Background

Effective postoperative analgesia plays a crucial role in enhancing recovery following laparoscopic surgeries. The transversus abdominis plane (TAP) block, when combined with adjuvants, has shown promising results in prolonging analgesia. Among the commonly studied adjuvants, magnesium sulphate and dexmedetomidine are frequently compared, but their relative efficacy remains debated. We hypothesized that magnesium sulphate would provide longer analgesia without increasing adverse effects.

Objective

The objective of this study is to compare the duration and quality of postoperative analgesia between two TAP block regimens of bupivacaine with magnesium sulphate versus bupivacaine with dexmedetomidine in ultrasound-guided TAP blocks for patients undergoing elective laparoscopic surgeries.

Methods

This was a prospective comparative study conducted on 60 adult patients, aged 18-55 years, undergoing elective laparoscopic surgeries. Patients were randomly allocated into two equal groups: a) group M: bupivacaine + magnesium sulphate, and b) group D: bupivacaine + dexmedetomidine.

The primary outcome was the duration of postoperative analgesia (time to first rescue analgesic). Secondary outcomes included VAS pain scores, total analgesic consumption in 24 hours, haemodynamic changes, and incidence of adverse events. Statistical analysis was performed using SPSS version 26.0 (IBM Corp., Armonk, NY), with a significance threshold set at p < 0.05.

Results

The mean duration of postoperative analgesia was significantly longer in the magnesium group compared to the dexmedetomidine group (13 ± 1.85 hours vs 12 ± 1.75 hours; p = 0.04). Postoperative VAS scores at all time intervals were slightly lower in the magnesium group but did not reach statistical significance (p > 0.05). Total rescue analgesic requirement in 24 hours was reduced in the magnesium group (78.3% vs. 63.4%, p = 0.02). Haemodynamic parameters remained stable across both groups, and adverse events were minimal and comparable.

Conclusion

Both magnesium sulphate and dexmedetomidine were effective adjuvants in TAP block. Magnesium sulphate was associated with a statistically significant but modest prolongation of postoperative analgesia, with comparable pain scores and safety profiles.