Dexmedetomidine or Fentanyl, Which One Is Better as an Adjunct Drug in Epidural Anesthesia and Causes More Postoperative Pain Reduction? A Comparative Study, a Randomized Clinical Trial.

OBJECTIVES: This study compared dexmedetomidine to fentanyl as an adjunct to ropivacaine for epidural anesthesia in patients undergoing femoral neck fracture surgery.

METHODS: A total of 56 patients in two different groups with dexmedetomidine and fentanyl underwent the epidural anesthesia method by ropivacaine. This study compared the onset and duration of sensory block, duration of motor block, visual analog scale (VAS) analgesia, and sedation score. The VAS and hemodynamics (e.g., heart rate and mean arterial pressure) were measured every 5 to 15 minutes, then every 15 minutes to the end of the surgery, and then in the 1st, 2nd, 4th, 6th, 12th, and 24th hours after surgery.

RESULTS: In the fentanyl group, the onset time of the sensory block was longer (P < 0.001), and the duration of the block was shorter than in the dexmedetomidine group (P = 0.045). In the fentanyl group, the onset time of motor block was longer than in the dexmedetomidine group (P < 0.001). The mean highest VAS score for each patient in the dexmedetomidine group was 4.9 ± 0.6, compared to the fentanyl group (5.8 ± 0.9), with a significant difference between the two groups (P < 0.001). The sedation score was higher from the 30th minute (P = 0.01) to the 120th minute (P = 0.04) in the patients of the dexmedetomidine group than in the fentanyl group. Side effects, such as dry mouth, hypotension, and bradycardia, were more common in the dexmedetomidine group, and nausea and vomiting were more common in the fentanyl group; however, there were no differences between the groups. There was no respiratory depression in both groups.

CONCLUSIONS: This study presented that dexmedetomidine as an adjuvant in epidural anesthesia for orthopedic femoral fracture surgery shortens the onset time of sensory and motor block, increases analgesia length, and prolongs anesthesia. Sedation with dexmedetomidine is better than fentanyl, with fewer side effects, and more effective as preemptive analgesia.