Efficacy of Clonidine as an Adjuvant to Ropivacaine in Transversus Abdominis Plane Block in Adult Renal Transplant Recipients: A Double-blinded Randomized Controlled Trial.

BACKGROUND AND AIMS: Transversus abdominis plane (TAP) block has been used to provide analgesia in renal transplant surgery with varying results. This study was designed to assess if the addition of clonidine in TAP block would decrease 24-h postoperative morphine consumption in adult renal transplant recipients.

MATERIALS AND METHODS: Forty adult patients undergoing renal transplantation under general anesthesia in a tertiary care hospital were randomized into either group RC (TAP block with 20 mL of 0.5% ropivacaine plus 2 μg.kg-1 clonidine) or group R (TAP block with 20 mL 0.5% ropivacaine) after induction of anesthesia. Postoperative analgesia was provided using patient-controlled morphine. The primary outcome was 24-h patient-controlled morphine consumption. The secondary outcomes were a) intraoperative hemodynamics, b) fentanyl and ephedrine requirement, c) postoperative pain using the Visual Analog Scale at 0, 2, 6, 12 and 24 hours, d) time to first postoperative analgesia, e) postoperative hemodynamics, and f) side effects.

RESULTS: There was no significant difference in postoperative morphine consumption between the groups (25 mg in group RC vs. 28.5 mg in group R) (median interquartile range) ( P = 0.439). Postoperative pain scores were comparable between the groups. Intraoperatively, fewer patients required rescue fentanyl in group RC (7 patients) as compared to group R (17 patients) ( P = 0.003). Significantly more patients in group RC required ephedrine boluses as compared to group R (9 patients in group RC vs. 2 in group R, P = 0.014).

CONCLUSIONS: The addition of 2 μg.kg-1 clonidine to ropivacaine in TAP block did not reduce 24-h postoperative morphine consumption after renal transplantation. It reduced the need for intraoperative analgesics but increased the need for intraoperative ephedrine administration.