title: A comparison of four stimulation patterns in axillary block.
abstract: OBJECTIVE
  Insufficient spread of the local anesthetic toward the retroarterial region of the neurovascular space may be responsible for inconsistent anesthesia of the upper limb after single-injection axillary block. We hypothesized that injection of the local anesthetic on a single radial-nerve stimulation would produce the same extent of anesthesia as either a single median-nerve stimulation, a double-stimulation technique (radial and musculocutaneous nerves), or a triple-stimulation technique (radial, musculocutaneous, and median nerves).
  
  
  METHODS
  One hundred twenty patients were randomly assigned to receive an axillary block by either median-nerve, radial-nerve, radial-nerve plus musculocutaneous-nerve, or triple-nerve stimulation with 40 mL of plain 1.5% mepivacaine. Patients were assessed for sensory block by the pinprick method at 5 and 20 minutes.
  
  
  RESULTS
  Radial-nerve stimulation produced more extensive anesthesia than did median-nerve stimulation. The rate of anesthesia at 20 minutes in the median-nerve cutaneous distribution was similar after median-nerve stimulation or radial-nerve stimulation. The ulnar nerve was more frequently blocked at 20 minutes after radial-nerve stimulation than after median-nerve stimulation. Extent of anesthesia at 20 minutes after radial-nerve plus musculocutaneous-nerve stimulation was similar to that produced by triple-nerve stimulation, except for lower rates of anesthesia that corresponded to the median nerve. All of the differences were statistically significant.
  
  
  CONCLUSIONS
  Musculocutaneous-nerve stimulation and radial-nerve stimulation play predominant roles in the success of axillary brachial plexus block, although a triple-nerve stimulation technique is still required to produce complete anesthesia of the upper limb.
authors: Department of Anesthesiology, Hospital Clínico Universitario de Santiago, Spain. jaimerodriguezgarcia@nacom.es
authors: Jaime
authors: J
authors: Rodríguez
authors: Manuel
authors: M
authors: Taboada
authors: Sabela
authors: S
authors: Del Río
authors: María
authors: M
authors: Bárcena
authors: Julián
authors: J
authors: Alvarez
mesh_terms: D000328:Adult; D000368:Aged; D001917:Brachial Plexus; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008619:Mepivacaine / Q000494:pharmacology; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011826:Radial Nerve / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation
chemical_list: D008619:Mepivacaine