Comparative study of dexmedetomidine versus fentanyl as adjuvants to bupivacaine in ultrasound-guided transversus abdominis plane block in patients undergoing radical cystectomy: a prospective randomised study

BACKGROUND: Transversus abdominis plane (TAP) block is beneficial for pain management after conducting abdominal surgery. OBJECTIVE: To compare the outcomes of dexmedetomidine and fentanyl, as adjuvants to bupivacaine, for ultrasound-guided TAP block analgesia among patients undergoing radical cystectomy for postoperative pain management. METHODS: This prospective, randomised, comparative study included a total of 60 patients, who underwent radical cystectomy. Participants were randomly divided into three categories with 20 subjects each; group B had patients who received a single shot US-guided TAP block on each side with 20 ml of 0.25% bupivacaine + 2 ml normal saline; group BF had patients who received a single shot US-guided TAP block on each side with 20 ml of 0.25% bupivacaine + 1 µg/kg fentanyl dissolved in 2 ml normal saline and group BD had patients who received a single shot US-guided TAP block on each side with 20 ml of 0.25% bupivacaine + 1 µg/kg dexmedetomidine dissolved in 2 ml normal saline.The researchers recorded the time taken for first rescue analgesia, total analgesic dose in the first 24 h after surgery, patient satisfaction, sedation score, and postoperative complications. RESULTS: The time taken for first rescue analgesia was significantly lengthier in group (BD) (8.90 ± 2.47) than (BF) (6.50 ± 1.43) and (B) (4.40 ± 1.05) groups. The total nalbuphine consumption, during the first 24 h, was significantly lower in (BD) (0.15 ± 0.00) group compared to (BF) (0.20 ± 0.07) and (B) (0.24 ± 0.08) groups. CONCLUSION: In comparison with fentanyl, as an adjuvant to bupivacaine, dexmedetomidine was found to be associated with prolonged postoperative analgesia, less postoperative pain scores and low opioid consumption. TRIAL REGISTRATION: This study was registered at Clinical Trials.gov on 23 March 2020 (registration number: NCT04318158).