The Effect of Fentanyl or Dexmedetomidine on the Ultrasound-Guided Paravertebral Block for Patients Undergoing Renal Surgeries: Randomized Controlled Trial

Objective: This study aimed to investigate the effect of the continuous paravertebral block using either fentanyl or dexmedetomidine as an additive to bupivacaine in patients undergoing renal surgeries. Methods: Ninety adult patients presented for renal surgeries under general anesthesia and ultrasound-guided continuous paravertebral block were allocated in this study and randomly distributed into three groups. All the patients received a loading and a maintenance doses of local anesthetic mixtures composed of bupivacaine alone in Control group with addition of fentanyl or dexmedetomidine in Fentanyl and Dexmedetomidine groups. The measurements included the postoperative analgesic consumption, the time for the first request for rescue analgesia, postoperative pain scores, hemodynamic parameters, and incidence of complication. Results: The addition of fentanyl or dexmedetomidine to plain bupivacaine in continuous paravertebral block significantly decreased the dose of postoperative morphine consumption from (11.33 ± 5.05 mg) to (7.33 ± 4.59 mg) (7.80 ± 4.15mg), significantly prolonged the time for first request of rescue analgesia from (6.87 ± 3.81 h) to (9.80 ± 4.50 h) (10.80 ± 5.22 h), and significantly decrease VAS score 2 h and 6 h postoperatively with insignificant difference between fentanyl and dexmedetomidine (p>0.05). Conclusion: Fentanyl or dexmedetomidine can be helpful as an adjuvant to bupivacaine (0.25%) in the continuous paravertebral block as they decreased the postoperative analgesic consumption without increased incidence of complication.