title: Randomized Comparison of Extrafascial Versus Subfascial Injection of Local Anesthetic During Ultrasound-Guided Supraclavicular Brachial Plexus Block.
abstract: OBJECTIVE
  The optimal site for local anesthetic injection during an ultrasound-guided supraclavicular brachial plexus block (BPB) is not known. We tested the hypothesis that local anesthetic injected deep to the "brachial plexus sheath" during supraclavicular BPB would produce faster onset of surgical anesthesia than an injection superficial to the sheath.
  
  
  METHODS
  After research ethics approval and informed consent, 32 patients undergoing upper-extremity surgery under an ultrasound-guided supraclavicular BPB were randomly assigned to receive 25 mL of a 1:1 mixture of 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine, deep to (subfascial, Gp SF) or superficial to (extrafascial, Gp EF) the brachial plexus sheath. Sensory-motor blockade of the ipsilateral musculocutaneous, median, radial, and ulnar nerves and time to "readiness for surgery" (defined as a sensory and motor block scale of 1 in all the 4 nerves tested) were assessed by a blinded observer, using a 3-point qualitative scale (2 to 0), every 5 minutes for 40 minutes and at 2, 4, 6, 8, 10, 12, and 24 hours after surgery.
  
  
  RESULTS
  The time to "readiness for surgery" was significantly shorter (Gp SF: 7 ± 3 minutes vs Gp EF: 20 ± 10 minutes; P < 0.001), and the duration of postoperative analgesia was longer (Gp SF: 9.3 ± 1.4 hours vs Gp EF: 6.1 ± 1.4 hours; P < 0.001) in the subfascial group than in the extrafascial group. There were no complications directly related to the technique or the local anesthetic injection.
  
  
  CONCLUSIONS
  Injection of local anesthetic deep to the brachial plexus sheath at the supraclavicular fossa, under ultrasound-guidance, results in faster onset of surgical anesthesia and prolonged duration of postoperative analgesia than an injection superficial to the sheath.
authors.affiliation: From the *Department of Anesthesiology & Critical Care, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth, Pillayarkuppam, Puducherry, India; and †Department of Anesthesia & Intensive care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China.
authors.forename: T
authors.initials: T
authors.lastname: Sivashanmugam
authors.forename: Suja
authors.initials: S
authors.lastname: Ray
authors.forename: M
authors.initials: M
authors.lastname: Ravishankar
authors.forename: V
authors.initials: V
authors.lastname: Jaya
authors.forename: E
authors.initials: E
authors.lastname: Selvam
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Karmakar
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D019162:Anesthetics, Combined / Q000008:administration & dosage* / Q000009:adverse effects; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D065527:Brachial Plexus Block / Q000009:adverse effects / Q000379:methods*; D002045:Bupivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D004338:Drug Combinations; D004837:Epinephrine / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D006801:Humans; D007194:India; D007267:Injections; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D019637:Orthopedic Procedures / Q000009:adverse effects; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D010149:Postoperative Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional; D034941:Upper Extremity / Q000294:innervation / Q000601:surgery*; D055815:Young Adult
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D004338:Drug Combinations; D008012:Lidocaine; D002045:Bupivacaine; D004837:Epinephrine