to assessthe impact of addition of Dexmedetomidine or Dexamethasone to Bupivacaine, on Duration of analgesia (time in hours to the first report of postoperative pain )at the surgical site

This randomized, controlled double blinded study included 42 adult patients undergoing arteriovenous fistula surgery. Ultrasound-guided supraclavicular brachial plexus block was initiated after placement of full monitoring . Supraclavicular brachial plexus block was achieved with the use of total volume 32 ml of anesthetic drugs in all patients. Bupivacaine 30 ml 0.25% was combined with 2 ml normal saline (control group A, n=14), Bupivacaine 30 ml 0.25% was combined with 50 microgram (0.5 ml) peri-neural dexmedetomidine plus 1.5 ml normal saline ( dexmedetomidine group B ,n=14), or Bupivacaine 30 ml 0.25% was combined with 4 mg peri neural dexamethasone (2 ml) ( dexamethasone group C, n=14).The onset and duration of sensory and motor blocks, the time to first request to postoperative rescue analgesic, Richmond Agitation-Sedation Score, hemodynamic data, visual analogue pain scores, were reported at predetermined time assessment points. Postoperative rescue intravenous fentanyl consumption over 24 hours and complications occurred were recorded.

Inclusion Criteria:

• All the patients included in the study aged 18 to 60 years old were on chronic hemodialysis and they had a hemodialysis session one day before the block performance

Exclusion Criteria:

• Neurological, neuromuscular, psychiatric disorders, hepatic, respiratory, or cardiac diseases; coagulation disorders; infection at the block injection site; patients with a body mass index more than 35; or patients who refused the procedure

double blind both anesthetist and patient not aware about type of local anesthesia