title: A prospective, randomized comparison between double-, triple-, and quadruple-injection ultrasound-guided axillary brachial plexus block.
abstract: BACKGROUND
  This prospective, randomized, observer-blinded study compared double-, triple-, and quadruple-injection ultrasound (US)-guided axillary brachial plexus block (AXB) for upper-extremity surgery.
  
  
  METHODS
  One hundred twenty patients were randomly allocated to receive a double- (n = 40), triple- (n = 40), or quadruple-injection (n = 40) US-guided AXB. The local anesthetic agent (lidocaine 1.5% with epinephrine 5 μg/mL) and total volume (35 mL) were identical in all subjects. For all 3 groups, the musculocutaneous nerve was identified and anesthetized first. Subsequently, a perivascular technique was performed. Lidocaine was deposited at the 6-o'clock position of the axillary artery for the 2-injection group. For the 3- and 4-injection groups, injections were carried out at the 12-/6-o'clock and 2-/10-/6-o'clock positions, respectively. During the performance of the block, the performance time, number of needle passes, and complications (vascular puncture, paresthesia) were recorded. Subsequently, a blinded observer assessed the onset time, block-related pain scores, and success rate (surgical anesthesia). The main outcome variable was the total anesthesia-related time (sum of performance and onset times).
  
  
  RESULTS
  No differences were observed among the 3 groups in terms of total anesthesia-related time (29.2-31.4 mins), success rate (90.0%-97.5%), block-related pain scores, vascular puncture, and paresthesia. Compared with its 3- and 4-injection counterparts, the double-injection technique required fewer needle passes (4.0 ± 1.6 vs 5.2-6.0 ± 1.7-2.8; both P ≤ 0.001).
  
  
  CONCLUSIONS
  Double-, triple-, and quadruple-injection US-guided perivascular AXB result in comparable success rates and total anesthesia-related times. Because it requires fewer needle passes, the double-injection technique provides a simple alternative for US-guided AXB.
authors.affiliation: Department of Anesthesia, Montreal General Hospital, McGill University, Montreal, Quebec, Canada. de_tran@hotmail.com
authors.forename: De Q H
authors.initials: DQ
authors.lastname: Tran
authors.forename: Kevin
authors.initials: K
authors.lastname: Pham
authors.forename: Shubada
authors.initials: S
authors.lastname: Dugani
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: Finlayson
mesh_terms: D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D001917:Brachial Plexus / Q000000981:diagnostic imaging* / Q000187:drug effects*; D005260:Female; D006801:Humans; D007267:Injections; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D017288:Pain Threshold / Q000187:drug effects; D010292:Paresthesia / Q000209:etiology; D011446:Prospective Studies; D011792:Quebec; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional; D034941:Upper Extremity / Q000294:innervation* / Q000601:surgery; D057772:Vascular System Injuries / Q000209:etiology
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine