Comparison of ketamine and alfaxalone for induction and maintenance of anaesthesia in ponies undergoing castration
Version of Record online: 10 JAN 2011
© 2011 The Authors. Veterinary Anaesthesia and Analgesia © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists
Veterinary Anaesthesia and Analgesia
Volume 38, Issue 1, pages 37–43, January 2011
How to Cite
Klöppel, H. and Leece, E. A. (2011), Comparison of ketamine and alfaxalone for induction and maintenance of anaesthesia in ponies undergoing castration. Veterinary Anaesthesia and Analgesia, 38: 37–43. doi: 10.1111/j.1467-2995.2010.00584.x
- Issue online: 10 JAN 2011
- Version of Record online: 10 JAN 2011
- Received 7 Feburary 2010; accepted 23 April 2010.
Objective To compare alfaxalone with ketamine for total intravenous anaesthesia in ponies undergoing castration.
Study design Prospective, randomised, blinded clinical study.
Animals Forty-two, 12-month-old Welsh Mountain ponies.
Methods Ponies were assigned randomly to receive ketamine or alfaxalone. After administration of romifidine 100 μg kg−1 and butorphanol 50 μg kg−1 intravenously (IV), sedation and response to tactile stimulation were scored. If sedation was insufficient, romifidine 30 μg kg−1 was administered IV. Anaesthesia was induced with ketamine 2.2 mg kg−1 or alfaxalone 1 mg kg−1, both in combination with diazepam 20 μg kg−1 IV. Time from end of injection to lateral recumbency was recorded. Simple descriptive scores were used to score quality of induction, surgical conditions and recovery. Ketamine 0.5 mg kg−1 or alfaxalone 0.2 mg kg−1 were administered if movement was observed. Times to first head lift, sternal recumbency and standing, and number of attempts needed were recorded. All scores were performed by the same observer, unaware of treatment. Normally distributed data were compared using t-test and non-normally distributed data with Mann–Whitney test. Level of significance was set at p < 0.05.
Results Three ponies needed additional sedation. Mean induction times were 30 ± 6 and 18 ± 4 seconds following ketamine and alfaxalone respectively (p < 0.0001). Additional doses were required by four ponies given ketamine and seven given alfaxalone. Sedation, induction and surgical scores were similar for both groups. Recovery scores (scale of 1–4 with 1 best) differed statistically between groups [ketamine group, median 1 (1–2); alfaxalone group 1.5 (1–4) (p = 0.04)]. No differences in anaesthesia time or times taken from end of surgery to head lift, sternal recumbency and standing were detected.
Conclusion and clinical relevance Induction times following alfaxalone were shorter than following ketamine. Both anaesthetic agents provided acceptable quality of anaesthesia for castration.