This prospective randomized double blind comparative study will be conducted at our institution over a period of 2 years. In this study 86 ASA grade I and II patients between age 20 years to 60 years with BMI <= 30kg/m2 posted for elective below elbow orthopaedic surgery requiring Ultrasound guided Infraclavicular block will be included.

After taking written informed consent from, patients will be randomized to 2 groups (n= 43 each ) by computer generated random number table. All patients will be thoroughly examined pre-operatively which includes blood pressure, heart rate, respiratory rate and systemic examination, and ASA grading. The patients with a contraindication to procedure like allergic reaction to local anesthetics or major neurological, cardiovascular, metabolic, respiratory, renal disease, or coagulation abnormalities will be excluded. 

After recording preoperative baseline Heart Rate and Blood Pressure  intravenous access is established using 18G cannula. Standard intraoperative monitoring includes ECG, NIBP, HR, and SPO2. Ringers lactate is used for replacement and maintenance fluid as per standard guidelines of perioperative fluid administration. The drug combination will be prepared by one anesthesiologist or pharmacist and will be given by another anesthesiologist who is blinded to the drug used in the study. Both the patients and the observer will be blinded to the study drug or the group.

Proper positioning for infraclavicular block with the patient supine and head turned to opposite side and arm abducted to 90 degree and the elbow fixed. Under all aseptic precautions Ultrasound guided Infraclavicular block is given in the below 2 groups 

In group M: The patients will be given 2ml of 10% Magnesium Sulfate with 20ml 0.5%levobupivacaine  in total 22ml solution

In group D: The patients will be given 2ml Dexamethasone with 20ml 0.5%levobupivacaine in total 22ml solution.

Onset time for sensory and motor block will be noted. The Sensory Block (SB) was assessed using pin prick test. All dermatomes supplied by radial, ulnar, median and musculocutaneous nerves were assessed. The SB was graded 0 = Normal sensation, 1=Loss of sensation to pin prick,2=Loss of touch sensation. The Motor Block (MB) was graded according to modified bromage scale which is 0=No movement in fingers, wrist and elbow, 1=Finger movement, 2=Flexion of wrist against gravity, 3=Flexion of elbow against gravity.

The onset time of SB is the time interval from injection of local anesthetic till the complete SB achieved. The duration of the SB is the time interval between onset of complete SB and complete resolution of SB. Duration of analgesia is the time between onset of complete SB and the first dose of post operative analgesia. The block is considered successful when sensory block is 2 and motor block is 0 within 30 min after local anesthetic is given, otherwise  block is considered as failed or inadequate.  

Post operative analgesia is achieved by giving diclofenac 75mg iv every 12hrs.

Pain assessment was done by using Visual Analogue Scale (VAS) which is expressed  on 11-point numerical scale 0-10 and recorded in the postoperative care unit at 0, 1, 2, 4, 6, 8, 12, 18, and 24 hours postoperative. 

0    = No pain (one extreme)

10  = Worst pain possible (other extreme)