Comparative evaluation of Alpha two agonists Dexmedetomidine with Clonidine as adjuvants to 0.25% Ropivacaine for Ultrasound Guided Supraclavicular Block: A randomised double-blind prospective study

Background: Various studies have investigated the role of different drugs as adjuncts to SBPB to prolong the duration and quality of analgesia without producing any major adverse effects. We conducted a study to compare the novel alpha 2 agonists (clonidine and dexmedetomidine) with respect to onset, duration of block and postoperative analgesia when added as adjuvants to the local anesthetic 0.25% ropivacaine. Method: A total of 60 patients, confirming to inclusion criteria, undergoing elective upper limb surgeries under SBPB, were enrolled for the study, over a period of 2 years. Sensory block was evaluated by Hollmen scale [17] and findings were recorded at an interval of every 2 min from time-0 till complete sensory block was achieved i.e Hollmen Score = 4 . Onset Time of Sensory Block, Time for complete sensory block and total duration of sensory block were recorded. Motor block was evaluated by using Bromage Scale for upper extremity and findings were again recorded at an interval of every 2 min from time-0 till complete loss of motor power was achieved i.e BS =3. Onset Time of Motor Block, Time for complete motor block and total duration of motor block were recorded. Level of sedation was assessed at an interval of every 20 min from Time-0 till the end of surgery using the 5 point sedation scale. Postoperatively, sensory block and motor block and post operative pain (by Visual Analogue Scale) were assessed. VAS was recorded at an interval of every 1hour till the score ≥ 4. Results: Statistical analysis was done by SPSS version 17 software for statistical analysis. The onset of sensory block was significantly faster and the onset of motor block was significantly early in Dexmedetomidine group compared to Clonidine group and the duration of sensory and motor block were significantly longer in the Dexmedetomidine group. Duration of analgesia was significantly more in Dexmedetomidine group compared to Clonidine group. Conclusion: Addition of 1 μg/kg of dexmedetomidine in contrast to addition of 1 μg/kg of clonidine as an adjuvant to 0.25% Ropivaciane in a volume of 20 ml, for Supraclavicular Brachial Plexus Block in arm and forearm surgeries shortens the onset time and prolongs the duration of sensory block, motor block and analgesia without producing any clinically significant side effects. However a much larger trial involving more patients is required to establish this result.