The purpose of this study is to compare the onset and duration of sensory and motor blockade with two different routes of dexmedetomidine viz. perineural and intramuscular as an adjuvant to 0.5% bupivacaine in ultrasound guided supraclavicular brachial plexus block. The study will be conducted for a period of 12 months. It will be a prospective, triple blind placebo control trial study. The patients will be allocated one of the three groups by block randomization. The study drug solution will be prepared by anesthesiologist not involved in the study. The anesthesiologist performing the block and anesthesiologist observing the patient, both will be blinded to the study groups. Data will be analyzed by the anesthesiologist who will be unaware of the group allocation.

The enrolled patients after fulfilling all the inclusion and exclusion criteria will be divided into 3 groups.(i) Group B (n=30) Control Group –20 ml of 0.5% Bupivacaine +1ml Normal Saline and 1ml Normal Saline intramuscular.(ii) Group BD (n=30) Dexmedetomidine Group–20 ml of 0.5% Bupivacaine + 50µg Dexmedetomidine in 1ml Normal Saline and 1ml Normal Saline intramuscular.(iii)Group BD_IM (n=30) Dexmedetomidine IM Group –20 ml of 0.5% Bupivacaine + 1ml Normal saline and 1µg/kg Dexmedetomidine intramuscular.(A total volume of 21ml will be given in brachial plexus block)

Sensory and motor blockade will be assessed in territories of three nerves (radial, ulnar and median)  for every 3 min after completion of injection till 30 minutes and then for every 30 minutes after the end of surgery till the first 12 h, thereafter hourly until the block will have completely worn off.Sensory block (three nerve territories) will be assessed by pin prick test using a 3-point scale: 0 = normal sensation, 1 = loss of sensation of pin prick (analgesia), and2 = loss of sensation of touch (anesthesia) on dorsum of hand around anatomical snuff box for radial nerve, on hypothenar eminence for ulnar nerve, on medial side of thenar eminence for median nerve.  Motor block will be determined by thumb abduction (radial nerve), thumb adduction (ulnar nerve), thumb opposition (median nerve). Further block assessment will be done at hourly intervals up to 24 hours by a blinded anesthesiologist.

The primary outcome measure in this study will be the time to first analgesic request.

The secondary outcome measures include the number of supplemental analgesic requirements, VAS pain, nausea, patient satisfaction and onset and duration of sensory block and motor block episode of hypotension and bradycardia.