title: Buprenorphine added to the local anesthetic for axillary brachial plexus block prolongs postoperative analgesia.
abstract: OBJECTIVE
  Buprenorphine added to local anesthetic solutions for supraclavicular block was found to triple postoperative analgesia duration in a previous study when compared with local anesthetic block alone. That study, however, did not control for potentially confounding factors, such as the possibility that buprenorphine was affecting analgesia through intramuscular absorption or via a spinal mechanism. To specifically delineate the role of buprenorphine in peripherally mediated opioid analgesia, the present study controlled for these 2 factors.
  
  
  METHODS
  Sixty American Society of Anesthesiologists (ASA) P.S. I and II, consenting adults for upper extremity surgery, were prospectively assigned randomly in double-blind fashion to 1 of 3 groups. Group I received local anesthetic (1% mepivacaine, 0.2% tetracaine, epinephrine 1:200,000), 40 mL, plus buprenorphine, 0.3 mg, for axillary block, and intramuscular (IM) saline. Group II received local anesthetic-only axillary block, and IM buprenorphine 0.3 mg. Group III received local anesthetic-only axillary block and IM saline. Postoperative pain onset and intensity were compared, as was analgesic medication use.
  
  
  RESULTS
  The mean duration of postoperative analgesia was 22.3 hours in Group I; 12.5 hours in group II, and 6.6 hours in group III. Differences between groups I and II were statistically significant (P =.0012). Differences both between groups I and III and II and III were also statistically significant (P <.001).
  
  
  CONCLUSIONS
  Buprenorphine-local anesthetic axillary perivascular brachial plexus block provided postoperative analgesia lasting 3 times longer than local anesthetic block alone and twice as long as buprenorphine given by IM injection plus local anesthetic-only block. This supports the concept of peripherally mediated opioid analgesia by buprenorphine.
authors.affiliation: Department of Anesthesiology and Pain Management, Cook County Hospital, Chicago, IL 60611, USA. kcandido@msn.com
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Candido
authors.forename: Alon P
authors.initials: AP
authors.lastname: Winnie
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: Ghaleb
authors.forename: Maher W
authors.initials: MW
authors.lastname: Fattouh
authors.forename: Carlo D
authors.initials: CD
authors.lastname: Franco
mesh_terms: D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D001917:Brachial Plexus; D002047:Buprenorphine / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block; D010149:Postoperative Pain / Q000188:drug therapy*
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D002047:Buprenorphine