A Randomized Double Blinded Trial Comparing Dexmedetomidine With Dexamethasone as an Adjunct to Ropivacaine in Ultrasound Guided Interscalene Block for Arthroscopic Shoulder Surgery.

Objective: To evaluate the analgesic effi cacy of dexamethasone (DXA) vs. dexmedetomidine (DXM) as an adjunct to ropivacaine in ultrasound-guided interscalene block (USG-ISB) for arthroscopic shoulder surgery.

Methods: In this randomized double-blinded controlled trial, 60 American Society of Anesthesiologists grade 1-2 patients, 18-65 years, scheduled for arthroscopic shoulder surgery were randomly allocated to either group 1 (USG-ISB given with 0.5% ropivacaine 20 mL with 2 mL of saline containing DXM 0.5 mcg/kg) or group 2 (same protocol but DXA 8 mg instead of DXM). ISB was performed with in-plane technique under USG. Following surgery under general anesthesia, the patients received intravenous patient-controlled analgesia with fentanyl. Data were collected at 2-hourly intervals up to 24 hours after USG-ISB. The primary outcome was the duration of analgesia. Secondary outcomes consisted of pain ratings, total cumulative postoperative fentanyl consumption, patient satisfaction, and adverse effects.

Results: The groups were comparable regarding baseline demographic and clinical characteristics including onset of sensory and motor block. The duration of postoperative analgesia for group 2 was signifi cantly longer than for group 1 (22.40 ± 2.16 h vs. 19.30 ± 3.80 h; p < 0.001). Group 2 also required less total median number of boluses than group 1 (0 vs. 3; p < 0.001), less total fentanyl consumption (10.00 mcg ± 24.20 vs. 40.33 mcg ± 38.70; p < 0.001), less pain scores, and greater satisfaction (99.30 ± 2.53 vs. 93.30 ± 11.50; p=0.007). Adverse effects were few and comparable in both groups.

Conclusion: Greater postoperative analgesia and opioid sparing effect was observed in patients receiving 8 mg DXA as adjunct for USG-ISB.