A prospective, randomised, double blind study comparing dexamethasone and dexmedetomidine as adjuvants to 0.2% ropivacaine for post-operative analgesia in ultrasound guided brachial plexus block

Abstract

The Adjuvants added to local anaesthetic increases the duration of post-operative analgesia and decreases the analgesic requirement in post-operative period. The study was conducted with the intent of comparing post-operative analgesic effect of Dexamethasone and Dexmedetomidine in ultrasound guided Brachial Plexus Block. A prospective, randomised, double blind study to compare post-operative analgesic effect of Dexamethasone and Dexmedetomidine as adjuvant to 0.2% Ropivacaine in Ultrasound Guided Brachial Plexus Block. 60 patients belonging to ASA I and ASA II scheduled for upper limb surgeries were included in the study after taking informed consent. Group A received 20ml of 0.2% Ropivacaine with 8mg of Dexamethasone. Group B received 20ml of 0.2% Ropivacaine with 50 µg of Dexmedetomidine. Our primary objective was to compare the time to first request for analgesia in both the groups. Secondary objective was to compare duration of sensory and motor block in post-operative period and to compare overall requirement for analgesia in 24 hours in both the groups. The mean duration of motor block in Dexamethasone group was 635.47 ± 26.29 minutes and in Dexmedetomidine group was 827.47 ± 54.62 minutes. Similarly, mean duration of sensory block was 681.5 ± 27.19 minutes in Dexamethasone group and 877.17 ± 52.85 minutes in Dexmedetomidine group. The mean duration of time to first rescue analgesic was 709.67+18.47 minutes in dexamethasone group and 910.2 ± 51.66 minutes in Dexmedetomidine group. Total analgesia given had significant statistical difference of 0.004 between the two groups, with mean of 1.23 ± 1.17 in Dexamethasone group and 0.4 ± 0.56 in Dexmedetomidine. However, at 2hr, 4hr, 8hr, 12hr, 18hr and 24 hr the difference in VAS scores was significant (p value <0.0001). Dexmedetomidine is better than Dexamethasone in prolonging duration of analgesia of the Brachial plexus block.