title: Detomidine reduces isoflurane anesthetic requirement (MAC) in horses.
abstract: OBJECTIVE
  To quantitate the dose- and time-related magnitude of the anesthetic sparing effect of, and selected physiological responses to detomidine during isoflurane anesthesia in horses.
  
  
  METHODS
  Randomized cross-over study.
  
  
  METHODS
  Three, healthy, young adult horses weighing 485 ± 14 kg.
  
  
  METHODS
  Horses were anesthetized on two occasions to determine the minimum alveolar concentration (MAC) of isoflurane in O2and then to measure the anesthetic sparing effect (time-related MAC reduction) following IV detomidine (0.03 and 0.06 mg kg-1). Selected common measures of cardiopulmonary function, blood glucose and urinary output were also recorded.
  
  
  RESULTS
  Isoflurane MAC was 1.44 ± 0.07% (mean ± SEM). This was reduced by 42.8 ± 5.4% and 44.8 ± 3.0% at 83 ± 23 and 125 ± 36 minutes, respectively, following 0.03 and 0.06 mg kg-1, detomidine. The MAC reduction was detomidine dose- and time-dependent. There was a tendency for mild cardiovascular and respiratory depression, especially following the higher detomidine dose. Detomidine increased both blood glucose and urine flow; the magnitude of these changes was time- and dose-dependent CONCLUSIONS: Detomidine reduces anesthetic requirement for isoflurane and increases blood glucose concentration and urine flow in horses. These changes were dose- and time-related.
  
  
  CONCLUSIONS
  The results imply potent anesthetic sparing actions by detomidine. The detomidine-related increased urine flow should be considered in designing anesthetic protocols for individual horses.
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616-8745, USA. Electronic address: epsteffey@ucdavis.edu.
authors.forename: Eugene P
authors.initials: EP
authors.lastname: Steffey
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616-8745, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Pascoe
keywords: MAC; alpha-2 agonist; detomidine; horse; isoflurane