Prospective randomized double blind study 40 ASA 1 and 2 patients studied & divided into Group I (IV Dexmedetomidine) receiving intravenous dexmedetomidine 1 mcg/kg loading dose over 10 mins, followed by continous infusion of dexmedetomidine at 0.4mcg/kg/min & Group P (perineural Dexmedetomidine) receiving perineural dexmedetomidine 1 mcg/kg. All patients received supraclavicular block with lignocaine 5mg/kg & bupivacaine 2mg/kg diluted with normal saline to volume of 40 ml

Mean onset of sensory block in group I is 2.3min and 3.65 min in group P (P value < 0.05). Mean onset of motor block in group I is 6.45 min and 5.35 min in group P (P value > 0.05) .Duration of sensory blockade 11.10 ± 1.40 hours in Group I and 8.60 ± 2.16 hours in Group P (P value < 0.05). The duration of motor blockade Group I 13.20 ± 1.50 hours & 10.00 ± 1.65 hours in Group P (P value < 0.05 which). Mean sedation scores during intra-operative period in group I is 3.34 while in group P is 3.25 (P value >0.05). Average time to rescue analgesia 22.06 ± 4.36 hr in Group I and 19.30±4.41 in Group P (P value > 0.05). Group I demonstrated lower pulse rate & blood pressure compared to group P with comparable SpO2 values

Perineural dexmedetomidine sedation with supraclavicular brachial plexus block produces late onset of sensory block,early onset of motor block , lesser duration of sensory and motor blockade, lesser duration of analgesia with early requirements of postoperative analgesics & stable hemodynamics compared to intravenous dexmedetomidine sedation.