Effectiveness of Rectus Sheath Block on Postoperative Analgesia in Scheduled Midline Laparotomy under General Anaesthesia

Abstract

Background: Midline laparotomy, a widely performed surgical procedure, is associated with significant postoperative pain that may delay recovery, prolong hospital stay and also lead to adverse surgical outcomes. As a part of multimodal analgesia, Rectus Sheath Block (RSB) may be a simple effective alternative that minimize postoperative complications and promote earlier recovery. The Objective of this study was to evaluate the effectiveness of RSB on postoperative pain relief in scheduled midline laparotomy under General Anaesthesia.

Methods: This study was carried out from July 2024 to July 2025 in the General Surgery and MIS operation theatre (OT) in the department of Anaesthesia, Analgesia & Intensive Care Medicine, Bangladesh Medical University. Participants were randomly allocated into two groups: Group-R received ultrasound-guided rectus sheath block (RSB) with 0.3 mL/kg of 0.25% bupivacaine on each side of abdomen before surgical incision while Control Group- C received same volume of Normal Saline as placebo. Postoperative pain intensity was assessed by visual analogue scale (VAS), measured immediately in the postanaesthesia care unit (PACU) and at 3, 6, 12, and 24 postoperative hours. Rescue opioid analgesia as Morphine (0.05 mg/kg IV) was given when pain intensity by VAS ≥4. First analgesic request time (minutes), total Morphine consumption (mg) in 24 hours, frequency of postoperative vomiting, perioperative haemodynamic parameters (HR, SBP, DBP, MAP and SpO2) and patient’s satisfaction (based on a questionnaire graded on 5-Points Likert scale) were recorded.

Results: A total of 60 patients were included in this interventional study based on the selection criteria. Immediate postoperative pain score in the PACU were significantly lower in Group-R (VAS 6.10 ± 1.38) compared to Group-C (VAS 7.11 ± 1.24), p = 0.0045. Pain scores at other time points (3, 6, 12 and 24 hours) were comparable between both groups. Time to first analgesic request in minutes was significantly longer in Group-R (121 ± 10.3 minutes) than in Group-C (36 ± 6.8 minutes), p < 0.001. Total Morphine consumption in 24 hours in mg was lower in Group-R compared to Group-C (13.83±2.89 vs 15.70±2.70, p = 0.012), frequency of vomiting was reduced in Group-R (13.3% vs 23.33%) though not statistically significant, p = 0.317. Haemodynamic parameters (HR, SBP, DBP, MAP and SpO2) remained stable and comparable throughout 24 hours of the perioperative period. patient’s satisfaction scores did not differ significantly (10% vs 3.3%, p = 0.3) between both groups but more patients were unsatisfied in Group-C compared to Group-R with a statistical significance (13.3% vs 36.7%, p = 0.03).

Conclusion: RSB administered prior to surgical incision provides effective immediate postoperative pain relief following scheduled midline laparotomy under General Anaesthesia.