Alfaxalone compared with ketamine for induction of anaesthesia in horses following xylazine and guaifenesin

Keates, Helen L., van Eps, Andrew W. and Pearson, Martin R. B. (2012) Alfaxalone compared with ketamine for induction of anaesthesia in horses following xylazine and guaifenesin. Veterinary Anaesthesia and Analgesia, 39 6: 591-598. doi:10.1111/j.1467-2995.2012.00756.x


Author Keates, Helen L.
van Eps, Andrew W.
Pearson, Martin R. B.
Title Alfaxalone compared with ketamine for induction of anaesthesia in horses following xylazine and guaifenesin
Journal name Veterinary Anaesthesia and Analgesia   Check publisher's open access policy
ISSN 1467-2987
1467-2995
Publication date 2012-07-24
Year available 2012
Sub-type Article (original research)
DOI 10.1111/j.1467-2995.2012.00756.x
Open Access Status Not yet assessed
Volume 39
Issue 6
Start page 591
End page 598
Total pages 8
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing
Language eng
Subject 3400 Veterinary
Abstract Objective To compare anaesthesia induced with either alfaxalone or ketamine in horses following premedication with xylazine and guaifenesin. Study design Randomized blinded cross-over experimental study. Animals Six adult horses, five Standardbreds and one Thoroughbred; two mares and four geldings. Methods Each horse received, on separate occasions, induction of anaesthesia with either ketamine 2.2 mg kg-1 or alfaxalone 1 mg kg-1. Premedication was with xylazine 0.5 mg kg-1 and guaifenesin 35 mg kg-1. Incidence of tremors/shaking after induction, recovery and ataxia on recovery were scored. Time to recovery was recorded. Partial pressure of arterial blood oxygen (PaO2) and carbon dioxide (PaO2), arterial blood pressures, heart rate (HR) and respiratory rates were recorded before premedication and at intervals during anaesthesia. Data were analyzed using Wilcoxon matched pairs signed rank test and are expressed as median (range). Results There was no difference in the quality of recovery or in ataxia scores. Horses receiving alfaxalone exhibited a higher incidence of tremors/shaking on induction compared with those receiving ketamine (five and one of six horses respectively). Horses recovered to standing similarly [28 (2447) minutes for alfaxalone; 22 (1835) for ketamine] but took longer to recover adequately to return to the paddock after alfaxalone [44 (3867) minutes] compared with ketamine [35 (3047)]. There was no statistical difference between treatments in effect on HR, PaO2 or PaCO2 although for both regimens, PaO2 decreased with respect to before premedication values. There was no difference between treatments in effect on blood pressure. Conclusions and clinical relevance Both alfaxalone and ketamine were effective at inducing anaesthesia, although at induction there were more muscle tremors after alfaxalone. As there were no differences between treatments in relation to cardiopulmonary responses or quality of recovery, and only minor differences in recovery times, both agents appear suitable for this purpose following the premedication regimen used in this study.
Formatted abstract
Objective  To compare anaesthesia induced with either alfaxalone or ketamine in horses following premedication with xylazine and guiafenesin.

Study design
  Randomized blinded cross-over experimental study.

Animals
  Six adult horses, five Standardbreds and one Thoroughbred; two mares and four geldings.

Methods 
Each horse received, on separate occasions, induction of anaesthesia with either ketamine 2.2 mg kg−1 or alfaxalone 1 mg kg−1. Premedication was with xylazine 0.5 mg kg−1 and guaifenesin 35 mg kg−1. Incidence of tremors/shaking after induction, recovery and ataxia on recovery were scored. Time to recovery was recorded. Partial pressure of arterial blood oxygen (PaO2) and carbon dioxide (PaO2), arterial blood pressures, heart rate (HR) and respiratory rates were recorded before premedication and at intervals during anaesthesia. Data were analyzed using Wilcoxon matched pairs signed rank test and are expressed as median (range).

Results  There was no difference in the quality of recovery or in ataxia scores. Horses receiving alfaxalone exhibited a higher incidence of tremors/shaking on induction compared with those receiving ketamine (five and one of six horses respectively). Horses recovered to standing similarly [28 (24–47) minutes for alfaxalone; 22 (18–35) for ketamine] but took longer to recover adequately to return to the paddock after alfaxalone [44 (38–67) minutes] compared with ketamine [35 (30–47)]. There was no statistical difference between treatments in effect on HR, PaO2 or PaCO2 although for both regimens, PaO2 decreased with respect to before premedication values. There was no difference between treatments in effect on blood pressure.

Conclusions and clinical relevance
  Both alfaxalone and ketamine were effective at inducing anaesthesia, although at induction there were more muscle tremors after alfaxalone. As there were no differences between treatments in relation to cardiopulmonary responses or quality of recovery, and only minor differences in recovery times, both agents appear suitable for this purpose following the premedication regimen used in this study.
Keyword Alfaxalone
Equine anaesthesia
Ketamine
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Early view - First published online: 24 JUL 2012

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Veterinary Science Publications
 
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Created: Wed, 25 Jul 2012, 21:22:06 EST by Annette Winter on behalf of School of Veterinary Science