title: Ultrasound guidance improves success rate of axillary brachial plexus block.
abstract: OBJECTIVE
  The purpose of this study is to determine if real time ultrasound guidance improves the success rate of axillary brachial plexus blockade.
  
  
  METHODS
  Patients undergoing elective hand surgery were randomly assigned to one of three groups. Axillary blocks were performed using three motor response endpoints in the nerve stimulator (NS) Group, real-time ultrasound guidance in the ultrasound (US) Group and combined ultrasound and nerve stimulation in the USNS Group. Following administration of a standardized solution containing 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine (total 42 mL), sensory and motor functions were assessed by a blinded observer every five minutes for 30 min. A successful block was defined as complete sensory loss in the median, radial and ulnar nerve distribution by 30 min. The need for local and general anesthesia supplementation and post-block adverse events were documented.
  
  
  RESULTS
  One hundred and eighty-eight patients completed the study. Block success rate was higher in Groups US and USNS (82.8% and 80.7%) than Group NS (62.9%) (P = 0.01 and 0.03 respectively). Fewer patients in Groups US and USNS required supplemental nerve blocks and/or general anesthesia. Postoperatively, axillary bruising and pain were reported more frequently in Group NS.
  
  
  CONCLUSIONS
  This study demonstrates that ultrasound guidance, with or without concomitant nerve stimulation, significantly improves the success rate of axillary brachial plexus block.
authors.affiliation: Department of Anesthesia, University of Toronto and Anesthesia & Pain Management, Toronto, Canada. vincent.chan@uhn.on.ca
authors.forename: Vincent W S
authors.initials: VW
authors.lastname: Chan
authors.forename: Anahi
authors.initials: A
authors.lastname: Perlas
authors.forename: Colin J L
authors.initials: CJ
authors.lastname: McCartney
authors.forename: Richard
authors.initials: R
authors.lastname: Brull
authors.forename: Daquan
authors.initials: D
authors.lastname: Xu
authors.forename: Sherif
authors.initials: S
authors.lastname: Abbas
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000768:Anesthesia, General / Q000706:statistics & numerical data; D001365:Axilla; D001917:Brachial Plexus / Q000000981:diagnostic imaging*; D004311:Double-Blind Method; D017558:Elective Surgical Procedures; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006225:Hand / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*