title: Ultrasound-guided supraclavicular brachial plexus block: single versus triple injection technique for upper limb arteriovenous access surgery.
abstract: BACKGROUND
  Although ultrasound-guided supraclavicular block has a good success rate, it remains unclear whether multiple injections are superior to single injection (SI). We compared the sensory block success rate of SI versus triple injection (TI).
  
  
  METHODS
  In this randomized double-blind study, 96 end-stage renal disease patients undergoing arteriovenous fistula creation or superficialization were randomly allocated to receive either SI or TI. The primary outcome was the combined score of sensory blockade of the 5 nerves (median, ulnar, radial, medial cutaneous nerve of the forearm, and musculocutaneous) measured at 5, 10, 15, and 20 minutes after injection. Secondary outcome variables were the time to onset of the blockade, performance time (time to do the block), separate success rate for each of the above nerves, success rate of surgical anesthesia, and the complication rate.
  
  
  RESULTS
  The combined success of the sensory block was 20% to 31% higher in the TI group than in the SI group at 10, 15, and 20 minutes after injection (all P < 0.035). The block of the musculocutaneous nerve in the TI group was faster and more successful than in the SI group, at all time points (all P < 0.026). The average time needed to perform the block was significantly longer in the TI than the SI group (6.5 ± 2.1 vs 4.7 ± 2.1 minutes, P = 0.001). The overall success of surgical anesthesia measured at 30 minutes did not differ significantly between the 2 groups (96% in TI vs 87% in SI, P = 0.253).
  
  
  CONCLUSIONS
  Although the performance time of the SI technique was shorter, TI had a faster onset and resulted in a more successful block of all nerves in the first 20 minutes.
authors.affiliation: From the *Department of Anesthesia, King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Kingdom Saudia Arabia; †Department of Anesthesia, University of Dammam, Dammam, Saudi Arabia; ‡Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas; and §Department of Anesthesia, Alexandria University, Alexandria, Egypt.
authors.forename: Samer A
authors.initials: SA
authors.lastname: Arab
authors.forename: Mohamad K
authors.initials: MK
authors.lastname: Alharbi
authors.forename: Eman M S
authors.initials: EM
authors.lastname: Nada
authors.forename: Derar A
authors.initials: DA
authors.lastname: Alrefai
authors.forename: Hany A
authors.initials: HA
authors.lastname: Mowafi
mesh_terms: D000328:Adult; D000368:Aged; D001917:Brachial Plexus / Q000000981:diagnostic imaging*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D010147:Pain Measurement; D010865:Pilot Projects; D011446:Prospective Studies; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*; D034941:Upper Extremity / Q000601:surgery*; D062666:Vascular Access Devices