EQUINE | Abstracts
A comparison of two ketamine doses for field anaesthesia
in horses undergoing castration
H. Harðardóttir, P. J. Murison, K. Blissitt, S. Olason, R. E. Clutton
First published: 24 November 2018
Background
Ketamine at 2.2 mg/kg given i.v. is often used to induce
anaesthesia for surgical procedures in horses under
field conditions. Commonly, additional doses are
needed to complete the surgery. We hypothesised that
surgical conditions would be improved when 5 mg/
kg of ketamine was used to induce anaesthesia, while
induction and recovery qualities would not differ from
those when 2.2 mg/kg ketamine was used.
Objective
To compare the anaesthetic effects of two ketamine
doses (5 and 2.2 mg/kg) during field anaesthesia for
castration of horses.
Study design
Prospective, randomised, blinded, clinical study.
Results
Ketamine 5 mg/kg provided better surgical conditions
and a more rapid induction. Recovery quality was
subjectively better in K2.2. Five horses in K2.2 and two
in K5 required additional ketamine doses.
Main limitations
While the pre‐anaesthetic sedation and benzodiazepine
doses were consistent among horses, the level of
sedation and muscle relaxation achieved differed.
Conclusion
A ketamine dose of 5 mg/kg can be used to improve the
quality of field anaesthesia for castration in Icelandic
horses. Although recovery quality is subjectively
better when using 2.2 mg/kg, no adverse events were
observed during recovery with either dose
Method
Seventy‐seven client‐owned Icelandic horses presented
for castration under field conditions were studied.
Pre‐anaesthetic medication was xylazine (0.7 mg/kg)
butorphanol (25 μg/kg) and acepromazine (50 μg/kg)
injected i.v. Anaesthesia was induced with either 2.2
mg/kg (K2.2) or 5 mg/kg (K5) i.v. of ketamine mixed
with diazepam (30 μg/kg). The quality of induction,
surgical conditions and recovery were compared using
subjective and objective measures, and the number of
additional ketamine doses recorded.
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• Equine Health Update •
https://doi.org/10.1111/evj.13052