title: Desflurane and sevoflurane elimination kinetics and recovery quality in horses.
abstract: OBJECTIVE
  To evaluate pharmacokinetics, recovery times, and recovery quality in horses anesthetized with 1.2 times the minimum alveolar concentration of sevoflurane or desflurane.
  
  
  METHODS
  6 healthy adult horses.
  
  
  METHODS
  Anesthesia was maintained with sevoflurane or desflurane for 2 hours at 1.2 times the minimum alveolar concentration. Horses recovered without assistance. During recovery, end-tidal gas samples were collected until horses spontaneously moved. Anesthetic concentrations were measured by use of gas chromatography. After a 1-week washout period, horses were anesthetized with the other inhalation agent. Video recordings of anesthetic recovery were evaluated for recovery quality on the basis of a visual analogue scale by investigators who were unaware of the anesthetic administered. Anesthetic washout curves were fit to a 2-compartment kinetic model with multivariate nonlinear regression. Normally distributed interval data were analyzed by means of paired Student t tests; ordinal or nonnormally distributed data were analyzed by means of Wilcoxon signed rank tests.
  
  
  RESULTS
  Horses recovered from both anesthetics without major injuries. Results for subjective recovery evaluations did not differ between anesthetics. Area under the elimination curve was significantly smaller and time to standing recovery was significantly less for desflurane than for sevoflurane, although distribution and elimination constants did not differ significantly between anesthetics.
  
  
  CONCLUSIONS
  Differences in area under elimination the curve between anesthetics indicated more rapid clearance for desflurane than for sevoflurane in horses, as predicted by anesthetic blood solubility differences in this species. More rapid elimination kinetics was associated with faster recovery times, but no association with improved subjective recovery quality was detected.
authors.affiliation: William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.
authors.forename: Ana C S
authors.initials: AC
authors.lastname: Valente
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Brosnan
authors.forename: Alonso G P
authors.initials: AG
authors.lastname: Guedes
mesh_terms: D000758:Anesthesia / Q000662:veterinary; D000762:Anesthesia Recovery Period; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D000077335:Desflurane; D005260:Female; D006736:Horses / Q000378:metabolism / Q000502:physiology*; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011650:Pulmonary Alveoli / Q000378:metabolism; D000077149:Sevoflurane; D064232:Visual Analog Scale
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D000077335:Desflurane; D007530:Isoflurane