Comparison of Hyperbaric Bupivacaine Alone versus Bupivacaine with Fentanyl for Spinal Anesthesia in Lower Abdominal and Lower Limb Surgery

Open Access

Abstract

Background: The addition of fentanyl to hyperbaric bupivacaine for spinal anesthesia may enhance block characteristics and postoperative analgesia. However, comparative data on the clinical benefits of this combination in lower abdominal and lower limb surgery remain limited. Objective: To compare the block characteristics and postoperative analgesic outcomes of hyperbaric bupivacaine alone versus bupivacaine with fentanyl for spinal anesthesia. Methods & Materials: This prospective comparative study was conducted at the Department of Anaesthesiology & ICU, National Institute of Traumatology & Orthopedic Rehabilitation (NITOR), Dhaka, Bangladesh, from January to December 2025. A total of 60 adult patients undergoing lower abdominal or lower limb surgery under spinal anesthesia were equally allocated to two groups: Group B (hyperbaric bupivacaine 0.5% 3 mL) and Group BF (hyperbaric bupivacaine 0.5% 3 mL with 25 µg fentanyl). Onset and duration of sensory and motor block, time to first analgesic request, and postoperative pain scores were recorded. Results: The mean duration of sensory block was significantly longer in Group BF (187.4 ± 22.6 minutes vs. 132.8 ± 18.4 minutes, p<0.001). Time to first analgesic request was also prolonged in Group BF (248.6 ± 34.2 minutes vs. 158.4 ± 28.6 minutes, p<0.001). Postoperative pain scores were consistently lower in the fentanyl group at all time points. Conclusion: The addition of fentanyl to hyperbaric bupivacaine significantly prolongs sensory block duration and postoperative analgesia without increasing complications. This combination is a safe and effective alternative for spinal anesthesia in lower abdominal and lower limb surgery.