A prospective randomized comparative study of analgesic effect of dexmedetomidine versus dexamethasone as an adjuvant to 0.75% ropivacaine in ultrasound-guided interscalene block

Background:Ultrasound (USG)-guided interscalene block (ISB) provides excellent anesthesia and analgesia for humerus surgery. Various adjuvants have been used to improve the quality of block and duration of analgesia. Aim:The aim of the study was to compare the efficacy of dexmedetomidine (DXM) and dexamethasone (DXA) as an adjuvant to 0.75% ropivacaine for interscalene brachial plexus block among patients undergoing humerus surgery. Settings and Design:The study design was a prospective randomized comparative study at a tertiary care teaching hospital. Materials and Methods:After ethical approval and CTRI registration, 52 patients of 18-60 years of age, American Society of Anesthesiology Grade I-II, scheduled for proximal and mid-shaft humerus surgery were randomly allocated in Groups A and B. Group A (n=26) received Ropivacaine 0.75% (20 ml) along with DXM 0.5 mu g/ Kg and 2 ml saline (total 22 ml) and Group B (n=26) received Ropivacaine 075% along with DXA 8 mg (total 22 ml). ISB was performed with an in-plane technique using a linear probe. Duration of analgesia, block characteristics (onset, complete sensory, and motor block), and complications were recorded and compared for 24 h. Statistical Analysis:Data were statistically analyzed with Social Science Statistics. Student's unpaired t-test and Chi-square tests were used, and all statistical tests were examined with P <= 0.05 level of significance. Results:The duration of analgesia in Group B was significantly longer than Group A (13 h 12 min 2 h 33 min-8 h 48 min +/- 1 h 52 min, P < 0.00001). The groups were comparable regarding block characteristics, baseline demographics, and intraoperative hemodynamic parameters. Conclusion:DXA as an adjuvant to ropivacaine provides analgesia for longer duration compared to DXM in USG-guided ISB.