title: Comparison between the effects of postanesthetic xylazine and dexmedetomidine on characteristics of recovery from sevoflurane anesthesia in horses.
abstract: OBJECTIVE
  To compare postanesthetic xylazine and dexmedetomidine on recovery characteristics from sevoflurane anesthesia in horses.
  
  
  METHODS
  Randomized, crossover study.
  
  
  METHODS
  Six geldings, mean±standard deviation (SD) (range), 17±4 (11-24) years and 527±80 (420-660) kg.
  
  
  METHODS
  Horses were anesthetized with sevoflurane for 60 minutes under standardized conditions for a regional limb perfusion study. In recovery, horses were administered either xylazine (200 μg kg-1) or dexmedetomidine (0.875 μg kg-1) intravenously. Recoveries were unassisted and were video-recorded for later evaluation of recovery events and quality by two individuals unaware of treatment allocation. Recovery quality was assessed using a 100 mm visual analog scale (VAS) (0=poor recovery, 100=excellent recovery), the Edinburgh Scoring System (ESS) (0-100; 100=excellent recovery) and the mean attempt interval (MAI) (longer=better). Data are mean±SD.
  
  
  RESULTS
  All recovery quality assessments (xylazine and dexmedetomidine, respectively: VAS: 71±21 mm, 84±13 mm; ESS: 65±22, 67±30; MAI: 52±24 minutes, 60±32 minutes) and events (first limb movement: 37±8 minutes, 42±10 minutes; first attempt to lift head: 44±12 minutes, 48±9 minutes; first attempt to sternal posture: 57±28 minutes, 50±7 minutes; number of head bangs: 2.0±3.0, 0.5±0.5; time to first attempt to stand: 72±6 minutes, 78±13 minutes; time to standing: 79±14 minutes, 84±13 minutes) did not differ significantly between treatments (p>0.05).
  
  
  CONCLUSIONS
  Recovery characteristics did not differ significantly between postanesthetic xylazine and dexmedetomidine following 1 hour of sevoflurane anesthesia in horses in this study. Further evaluations in more horses and in younger horses are required to confirm these results.
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA; Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, MN, USA. Electronic address: guede003@umn.edu.
authors.forename: Alonso G P
authors.initials: AGP
authors.lastname: Guedes
authors.affiliation: Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors.forename: Caitlin C
authors.initials: CC
authors.lastname: Tearney
authors.affiliation: Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors.forename: Alessia
authors.initials: A
authors.lastname: Cenani
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors.forename: Fabio
authors.initials: F
authors.lastname: Aristizabal
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: Nieto
mesh_terms: D000758:Anesthesia / Q000379:methods / Q000662:veterinary*; D000762:Anesthesia Recovery Period; D018685:Anesthetics, Inhalation; D000818:Animals; D018592:Cross-Over Studies; D020927:Dexmedetomidine / Q000494:pharmacology*; D006736:Horses; D007530:Isoflurane; D008297:Male; D008738:Methyl Ethers; D000077149:Sevoflurane; D014991:Xylazine / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D014991:Xylazine; D000077149:Sevoflurane; D020927:Dexmedetomidine; D007530:Isoflurane
keywords: complications; inhalation; sedation; α(2)-adrenergic agonist