title: Dexmedetomidine as an adjuvant to ropivacaine prolongs peripheral nerve block: a volunteer study.
abstract: BACKGROUND
  Dexmedetomidine is an α-2-receptor agonist which might be used as an additive to local anaesthetics for various regional anaesthetic techniques. We therefore designed this prospective, double-blinded, controlled volunteer study to investigate the effects of dexmedetomidine as an adjuvant to ropivacaine on peripheral nerve block.
  
  
  METHODS
  Ultrasound-guided ulnar nerve block (UNB) was performed in 36 volunteers with either 3 ml ropivacaine 0.75% (R), 3 ml ropivacaine 0.75% plus 20 µg dexmedetomidine (RpD), or 3 ml ropivacaine 0.75% plus systemic 20 µg dexmedetomidine (RsD). UNB-related sensory and motor scores were evaluated.
  
  
  RESULTS
  Sensory onset time of UNB was not different between the study groups, whereas motor onset time was significantly faster in Group RpD when compared with the other study groups [mean (sd)] [21 (15) vs 43 (25) min in Group RsD and 47 (36) min in Group R, P<0.05 Group RpD vs other groups]. The duration of sensory block was 350 (54) min in Group R, 555 (118) min in Group RpD, and 395 (40) min in Group RsD (P<0.01 Group RpD vs other groups, P<0.05 Group RsD vs Group R). Motor block duration was similar to the duration of sensory block.
  
  
  CONCLUSIONS
  A profound prolongation of UNB of ∼60% was detected with perineural dexmedetomidine when added to 0.75% ropivacaine. The systemic administration of 20 µg dexmedetomidine resulted in a prolongation of ∼10% during UNB with 0.75% ropivacaine. Eudra-CT No.: 2012-000030-19.
authors.affiliation: Department of Anaesthesia, Intensive Care Medicine and Pain Therapy, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: D
authors.initials: D
authors.lastname: Marhofer
authors.forename: S C
authors.initials: SC
authors.lastname: Kettner
authors.forename: P
authors.initials: P
authors.lastname: Marhofer
authors.forename: S
authors.initials: S
authors.lastname: Pils
authors.forename: M
authors.initials: M
authors.lastname: Weber
authors.forename: M
authors.initials: M
authors.lastname: Zeitlinger
mesh_terms: D000759:Adjuvants, Anesthesia / Q000009:adverse effects; D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000009:adverse effects; D000328:Adult; D000577:Amides / Q000009:adverse effects; D000779:Anesthetics, Local / Q000009:adverse effects; D020927:Dexmedetomidine / Q000009:adverse effects; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009407:Nerve Block / Q000379:methods*; D010525:Peripheral Nerves; D011446:Prospective Studies; D000077212:Ropivacaine; D014459:Ulnar Nerve; D018084:Ultrasonography, Interventional; D055815:Young Adult
chemical_list: D000759:Adjuvants, Anesthesia; D000316:Adrenergic alpha-Agonists; D000577:Amides; D000779:Anesthetics, Local; D020927:Dexmedetomidine; D000077212:Ropivacaine