Anaesthetic and cardiorespiratory effects of a constant-rate infusion of alfaxalone in desflurane-anaesthetised sheep
- M. del Mar Granados, DVM, PhD1,
- J. Manuel Domínguez, DVM, PhD1,
- A. Fernández-Sarmiento, DVM, PhD1,
- F. Javier Funes, DVM1,
- J. Morgaz, DVM, PhD1,
- R. Navarrete, DVM, PhD1,
- J. Ma Carrillo, DVM, PhD2,
- M. Rubio, DVM, PhD2,
- P. Muñoz-Rascón, DVM1,
- I. A. Gómez de Segura, DVM, PhD, Dip ECLAM3 and
- R. J. Gómez-Villamandos, DVM, PhD1
- 1Department of Animal Medicine and Surgery, Anaesthesia Unit, Veterinary Faculty, University of Córdoba, Córdoba, Spain
- 2Department of Animal Medicine and Surgery, Veterinary Faculty, CEU-Cardenal Herrera University, Valencia, Spain
- 3Department of Animal Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
- E-mail for correspondence: .
A prospective, randomised, blinded controlled study was performed to determine the anaesthetic and cardiorespiratory effects of a constant-rate infusion (CRI) of alfaxalone in 12 sheep anaesthetised with desflurane, and undergoing experimental orthopaedic surgery. Sheep were sedated with dexmedetomidine (4 μg/kg, intravenously) and butorphanol (0.3 mg/kg, intravenously). Anaesthesia was induced with alfaxalone (1 mg/kg/minute to effect, intravenously) and maintained with desflurane in oxygen and alfaxalone 0.07 mg/kg/minute or saline for 150 minutes (range 150–166 minutes). The anaesthetic induction dose of alfaxalone, the desflurane expiratory fraction required for anaesthetic maintenance, cardiorespiratory measurements and blood-gases were recorded at predetermined intervals. Quality of sedation, anaesthetic induction and recovery were assessed. The alfaxalone induction dose was 1.7 mg/kg (1.2 to 2.6 mg/kg). The desflurane expiratory fraction was lower (22 per cent) in sheep receiving alfaxalone CRI (P = 0). Also, heart rate (P = 0), cardiac index (P = 0.002), stroke index (P = 0) and contractility (P = 0) were higher, and systemic vascular resistance (P = 0.002) was lower. Although respiratory rate tended to be higher with alfaxalone, there was no difference in PCO2 between the groups. Recovery times were significantly longer in sheep given alfaxalone (25.4 v 9.5 minutes) but recovery quality was similar. Alfaxalone reduced requirements of desflurane and maintained similar cardiorespiratory function, but recovery time was more prolonged.
- Accepted May 22, 2012.
- Published Online First 11 July 2012
- British Veterinary Association