title: Needle placement and injection posterior to the axillary artery may predict successful infraclavicular brachial plexus block: a report of three cases.
abstract: OBJECTIVE
  The combined use of ultrasound and nerve stimulation for localization of the brachial plexus during infraclavicular block has not been evaluated. We describe three cases of infraclavicular block where we used ultrasound to place the needle and catheter, observe type of muscle twitch obtained and local anesthetic spread after injection.
  
  
  METHODS
  Injection of local anesthetic after obtaining proximal muscle stimulation was associated with local anesthetic spread between the axillary artery and pectoral muscle. This resulted in block failure (case 1). In case 2, proximal stimulation was associated with anterior spread after a test injection. The needle and subsequently the catheter were repositioned posterior to the axillary artery and distal muscle stimulation obtained. Injection through the catheter resulted in local anesthetic spread posterior to the artery and successful block. In case 3, no distal twitch could be obtained but in light of previous experience the needle and then the catheter were placed posterior to the axillary artery. Posterior local anesthetic spread was observed and successful block ensued despite absence of any muscle stimulation.
  
  
  CONCLUSIONS
  Ultrasound guidance during infraclavicular brachial plexus block enables direct visualization of needle/catheter tip location and confirmation of appropriate local anesthetic spread. Our early experience suggests that spread of injectate posterior to the second part of the axillary artery is associated with successful block.
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, 399 Bathurst St., EC 2-046, Toronto, Ontario M5T 2S8, Canada.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Porter
authors.forename: Colin J L
authors.initials: CJ
authors.lastname: McCartney
authors.forename: Vincent W S
authors.initials: VW
authors.lastname: Chan
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000493:pharmacokinetics; D001366:Axillary Artery / Q000000981:diagnostic imaging; D001917:Brachial Plexus / Q000000981:diagnostic imaging; D004558:Electric Stimulation; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006225:Hand / Q000601:surgery; D006801:Humans; D007267:Injections; D008012:Lidocaine / Q000493:pharmacokinetics; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D009339:Needles; D009407:Nerve Block / Q000379:methods*; D019637:Orthopedic Procedures; D014463:Ultrasonography; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D014662:Vasoconstrictor Agents; D008012:Lidocaine; D004837:Epinephrine