Comparative study of dexmedetomidine or fentanyl as an adjuvant to epidural bupivacaine for prevention of stump and phantom pain in adult patients undergoing above-knee or below-knee amputation: a randomized prospective trial

Abstract

Background Phantom-limb pain is one of the most difficult-to-treat chronic pain syndromes. In this randomized prospective trial, we studied the effect of administering fentanyl or dexmedetomidine as additive to bupivacaine in epidural catheter in perioperative period to reduce acute postoperative stump and phantom pain and opioid consumption in patients undergoing unilateral above- or below-knee amputation.Patients and methods Over 2 years, 62 patients with American Society of Anesthesiologists physical status I–II scheduled for unilateral knee amputation were analyzed. In this prospective study, two equal groups of patients randomly received dexmedetomidine or fentanyl as epidural infusion 24 h before operation and 72 h after surgery. Visual analog scale, sedation scale, patient satisfaction, incidence of phantom, and stump pain and cumulative opioid consumption over 3 days were used to compare the two groups.Results Incidence of postoperative stump and phantom pain in group D was less significantly in comparison with group F in the first 72 h postoperatively. Moreover, after 6 months, we found the same result. Patients’ satisfaction was significantly higher in group D in comparison with group F (P˂0.01). Visual analog scale was statistically significant lower in group D than group F in the 72-h postoperative period. This led to the more use of rescue analgesic (meperidine) in group F 232±23.1 mg than group D 142.2±46.68 mg. There was a statistically significant increase in preoperative sedation score in group D. Patients in group D experienced bradycardia and hypotension significantly more than group F. However, patients in group F experienced significantly from itching than group D.Conclusion Adding dexmedetomidine to bupivacaine as epidural infusion has been found to provide better postoperative analgesia, reduce opioid consumption, and decrease incidence of phantom and stump pain. It also improves patient satisfaction and decreases intensity of pain.