title: Evaluation of infusions of xylazine with ketamine or propofol to modulate recovery following sevoflurane anesthesia in horses.
abstract: OBJECTIVE
  To determine whether infusion of xylazine and ketamine or xylazine and propofol after sevoflurane administration in horses would improve the quality of recovery from anesthesia.
  
  
  METHODS
  6 healthy adult horses.
  
  
  METHODS
  For each horse, anesthesia was induced by administration of xylazine, diazepam, and ketamine and maintained with sevoflurane for approximately 90 minutes (of which the last 60 minutes were under steady-state conditions) 3 times at 1-week intervals. For 1 anesthetic episode, each horse was allowed to recover from sevoflurane anesthesia; for the other 2 episodes, xylazine and ketamine or xylazine and propofol were infused for 30 or 15 minutes, respectively, after termination of sevoflurane administration. Selected cardiopulmonary variables were measured during anesthesia and recovery. Recovery events were monitored and subjectively scored.
  
  
  RESULTS
  Cardiopulmonary variables differed minimally among treatments, although the xylazine-propofol infusion was associated with greater respiratory depression than was the xylazine-ketamine infusion. Interval from discontinuation of sevoflurane or infusion administration to standing did not differ significantly among treatments, but the number of attempts required to stand successfully was significantly lower after xylazine-propofol infusion, compared with the number of attempts after sevoflurane alone. Scores for recovery from anesthesia were significantly lower (ie, better recovery) after either infusion, compared with scores for sevoflurane administration alone.
  
  
  CONCLUSIONS
  Xylazine-ketamine or xylazine-propofol infusion significantly improved quality of recovery from sevoflurane anesthesia in horses. Xylazine-ketamine or xylazine-propofol infusions may be of benefit during recovery from sevoflurane anesthesia in horses for which a smooth recovery is particularly critical. However, oxygenation and ventilation should be monitored carefully.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA. aewagner@colostate.edu
authors.forename: Ann E
authors.initials: AE
authors.lastname: Wagner
authors.forename: Khursheed R
authors.initials: KR
authors.lastname: Mama
authors.forename: Eugene P
authors.initials: EP
authors.lastname: Steffey
authors.forename: Peter W
authors.initials: PW
authors.lastname: Hellyer
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General / Q000662:veterinary; D000769:Anesthesia, Inhalation / Q000662:veterinary; D019162:Anesthetics, Combined / Q000008:administration & dosage* / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D006339:Heart Rate; D006736:Horses; D007262:Infusions, Intravenous / Q000662:veterinary; D007649:Ketamine / Q000008:administration & dosage* / Q000494:pharmacology; D008738:Methyl Ethers / Q000008:administration & dosage / Q000494:pharmacology; D009043:Motor Activity; D010100:Oxygen / Q000097:blood; D015742:Propofol / Q000008:administration & dosage* / Q000494:pharmacology; D012119:Respiration; D000077149:Sevoflurane; D013997:Time Factors; D014991:Xylazine / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000700:Analgesics; D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D014991:Xylazine; D000077149:Sevoflurane; D007649:Ketamine; D010100:Oxygen; D015742:Propofol