title: Dexamethasone and Clonidine, but not Epinephrine, Prolong Duration of Ropivacaine Brachial Plexus Blocks, Cross-Sectional Analysis in Outpatient Surgery Setting.
abstract: OBJECTIVE
  The primary aim of this study is to determine the effect of adding dexamethasone, clonidine or both with and without epinephrine to ropivacaine and bupivacaine brachial plexus blocks.
  
  
  METHODS
  Observational study of prospectively collected data.
  
  
  METHODS
  Single academic outpatient surgery center.
  
  
  METHODS
  We evaluated 5,515 patient entries who received brachial plexus block (BPB). Multiple, rescue, unsuccessful, and distal nerve blocks of the upper extremity were excluded. The duration was calculated from the time the block was performed until the resolution of the block by patient report. Block durations were compared using Analysis of Variance.
  
  
  RESULTS
  After exclusions, 3,706 nerve blocks were analyzed. The median concentration of ropivacaine used was 0.5%. Both clonidine and dexamethasone significantly increased block duration by 1.1 and 3.0 hours, respectively. Combining clonidine and dexamethasone with ropivacaine increased block duration by 6.2 hours (p<0.001) when compared to ropivacaine alone. Dexamethasone and Clonidine increased block duration by 5.2 hours (p<0.001) when compared to clonidine alone and by 3.2 hours (p<0.001) compared to dexamethasone alone. The addition of epinephrine to any of the adjuvants made no statistically significant difference to the duration of action except when it was added to dexamethasone.
  
  
  CONCLUSIONS
  For brachial plexus blocks, epinephrine did not affect the duration of analgesia when added to ropivacaine. Epinephrine did not enhance the observed increase of block duration induced by clonidine or the combination of clonidine and dexamethasone. The most block duration enhancement was observed when combination of clonidine and dexamethasone were added to ropivacaine.
authors.affiliation: Division of Anesthesiology, Critical Care Medicine.
authors.forename: Nahel N
authors.initials: NN
authors.lastname: Saied
authors.affiliation: Division of Multispecialty Adult Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Rajnish K
authors.initials: RK
authors.lastname: Gupta
authors.affiliation: Departments of Anesthesia.
authors.forename: Lina
authors.initials: L
authors.lastname: Saffour
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Helwani
mesh_terms: D000328:Adult; D000368:Aged; D000556:Ambulatory Surgical Procedures; D000577:Amides / Q000008:administration & dosage*; D000700:Analgesics / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D065527:Brachial Plexus Block / Q000379:methods*; D003000:Clonidine; D003430:Cross-Sectional Studies; D003907:Dexamethasone / Q000008:administration & dosage; D004359:Drug Therapy, Combination / Q000379:methods; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059408:Pain Management / Q000379:methods; D010149:Postoperative Pain / Q000517:prevention & control*; D000077212:Ropivacaine; D013997:Time Factors
chemical_list: D000577:Amides; D000700:Analgesics; D000779:Anesthetics, Local; D000077212:Ropivacaine; D003907:Dexamethasone; D003000:Clonidine; D004837:Epinephrine