Cardiopulmonary effects of desflurane in horses.
OBJECTIVE
To determine the cardiopulmonary effects of desflurane (DES) in horses.


METHODS
Six healthy adult horses, three males and three females, aged 9 +/- 4 (mean +/- SD) years and weighing 370 +/- 36 kg.


METHODS
Anaesthesia was induced with an O2 (10 L minute(-1)) and DES mixture (vaporizer setting 18%). After oro-tracheal intubation, horses were positioned in right lateral recumbency. Anaesthesia was maintained with DES in O2 (20 mL kg(-1) minute(-1)) delivered through a large animal circle breathing system. The minimum alveolar concentration of DES (MAC(DES)) that prevented purposeful movement in response to 60 seconds of electrical stimulation of the oral mucous membranes was determined for each horse. The delivered concentration of DES was then increased to achieve end-tidal concentrations corresponding to 1.5 x MAC(DES), 1.75 x MAC(DES), and 2.0 x MAC(DES). Heart rate (HR), mean arterial blood pressure (MAP), respiratory rate (fr), tidal volume (VT), minute volume (VM) and core temperature were determined, and blood samples for arterial blood gas analysis taken at each DES concentration. All data were analysed by two-way anova for repeated measures and Fisher's test for multiple comparisons. A probability level of p < 0.05 was applied.


RESULTS
Desflurane concentrations of 2.0 x MAC(DES) increased HR whereas lower concentrations did not. Mean arterial pressure was not affected by 1.0 x MAC(DES) 1.5 x MAC(DES) or 1.75 x MAC(DES), whereas it decreased at 2.0 x MAC(DES). All concentrations of DES examined significantly depressed fr, VT and VM.


CONCLUSIONS
Desflurane concentrations between 1.0 and 1.75 x MAC(DES) reduces fr and VM but does not affect HR or MAP in horses.
Santos
Martín
M
Departamento de Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
López-Sanromán
Javier
J
García-Iturralde
Palma
P
Fuente
María
M
Tendillo
Francisco J
FJ
D000704:Analysis of Variance; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects*; D002245:Carbon Dioxide / Q000097:blood; D000077335:Desflurane; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006736:Horses / Q000502:physiology*; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D012123:Pulmonary Ventilation / Q000187:drug effects; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects
D018685:Anesthetics, Inhalation; D002245:Carbon Dioxide; D000077335:Desflurane; D007530:Isoflurane