EFFICACY OF THE ERECTOR SPINAE PLANE (ESP) BLOCK IN REDUCING POSTOPERATIVE OPIOID CONSUMPTION AFTER OPEN ABDOMINAL SURGERY

Abstract

Background: To evaluate the efficacy of bilateral ultrasound-guided erector spinae plane (ESP) block in reducing postoperative opioid consumption and improving pain control in patients undergoing open abdominal surgery under general anesthesia. Study Duration to June 2025 to March 2026. Study Place Department of Anaesthesia in collaboration with departments of General Surgery, Urology and Gynaecology, Ghurki Trust Teaching Hospital Lahore, Pakistan Materials and Methods: This prospective, randomized controlled trial enrolled 80 adult patients (ASA I-II) scheduled for elective open abdominal surgery. Patients were randomly allocated into two groups: Group A (ESP block group, n=40) received bilateral ultrasound-guided ESP block with 20 mL of 0.25% bupivacaine on each side (total 40 mL) after induction of general anesthesia, in addition to standard postoperative analgesia; Group B (control group, n=40) received standard postoperative analgesia alone. Postoperatively, both groups received IV paracetamol 1g every 6 hours. Rescue analgesia (nalbuphine 4mg IV) was administered when VAS score exceeded 5. Primary outcomes were total postoperative opioid consumption at 24 hours and time to first rescue analgesia. Secondary outcomes included VAS scores at 4, 8, 12, and 24 hours postoperatively, incidence of postoperative nausea and vomiting (PONV), and patient satisfaction scores. Results: The ESP block group demonstrated significantly lower mean (SD) 24 hour opioid consumption compared to the control group (3.8 ± 2.4 mg morphine milligram equivalents vs. 12.6 ± 4.2 mg; p < 0.001). Time to first rescue analgesia was significantly prolonged in the ESP group (mean 14.2 ± 3.6 hours vs. 4.8 ± 1.9 hours; p < 0.001). VAS scores were significantly lower in the ESP group at all-time points (p < 0.01). The incidence of PONV was significantly reduced in the ESP group (12.5% vs. 37.5%; p = 0.018). Patient satisfaction scores were higher in the ESP group (8.4 ± 0.9 vs. 6.2 ± 1.1; p < 0.001). No block-related complications were observed. Conclusion: Bilateral ultrasound-guided erector spinae plane block significantly reduces postoperative opioid consumption, prolongs time to first rescue analgesia, provides superior pain control, and reduces opioid-related side effects in patients undergoing open abdominal surgery. ESP block is a safe, effective, and easily reproducible regional analgesic technique that should be incorporated into multimodal analgesia protocols for open abdominal surgery. Keywords: Erector spinae plane block, ESP block, open abdominal surgery, postoperative analgesia, opioid consumption, multimodal analgesia, ultrasound guided regional anesthesia.