Comparison of alfaxalone, ketamine and thiopental for anaesthetic induction and recovery in Thoroughbred horses premedicated with medetomidine and midazolam.
Abstract: There is limited information on clinical use of the new injectable anaesthetic agent alfaxalone in Thoroughbred horses. Objective: To compare anaesthetic induction and recovery characteristics and cardiopulmonary responses between alfaxalone, ketamine and thiopental in Thoroughbred horses premedicated with medetomidine and midazolam. Methods: Randomised blinded experimental cross-over study. Methods: Six Thoroughbred horses were anaesthetised 3 times with alfaxalone 1 mg/kg bwt, ketamine 2.5 mg/kg bwt or thiopental 4 mg/kg bwt after premedication with medetomidine 6 μg/kg bwt and midazolam 20 μg/kg bwt. Qualities of anaesthetic induction and recovery were scored on a scale of 1 (poor) to 5 (excellent). Induction time and recovery time were recorded. Cardiopulmonary values (heart rate, respiratory rate, arterial blood pressures, and arterial blood gases) were recorded throughout anaesthesia. Data were analysed with nonparametric methods. Results: The anaesthetic induction (P = 0.2) and recovery (P = 0.1) quality scores (median, range) were not different amongst protocols and were 4.0, 3-5; 5.0, 4-5; 4.5, 3-5; and 4.5, 3-5; 3.5, 2-5; 4.0, 2-5 for alfaxalone, ketamine and thiopental, respectively. Induction time for ketamine (67, 53-89 s) was significantly longer than that for alfaxalone (49, 40-51 s, P = 0.01) and thiopental (48, 43-50 s, P = 0.01). Time to standing for alfaxalone (44, 40-63 min, P = 0.01) and thiopental (39, 30-58 min, P = 0.01) was significantly longer than that for ketamine (25, 18-26 min). Cardiovascular values were maintained within the clinically acceptable level throughout anaesthesia. Respiratory rate significantly decreased during anaesthesia for all 3 drugs; however, spontaneous breathing did not disappear, and PaCO values were maintained at approximately 50 mmHg. Conclusions: All 3 drugs showed similar effects in relation to anaesthetic induction and recovery qualities and cardiopulmonary responses. However, alfaxalone and thiopental prolonged recovery time compared with ketamine.
© 2015 EVJ Ltd.
Publication Date: 2016-02-06 PubMed ID: 26850885DOI: 10.1111/evj.12548Google Scholar: Lookup
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- Journal Article
Summary
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The research compares the effects and efficiency of three anaesthetic agents – alfaxalone, ketamine, and thiopental in Thoroughbred horses. The results of the study indicate that though all three drugs have similar effects on anaesthetic induction and recovery qualities as well as cardiopulmonary responses, alfaxalone and thiopental were found to prolong recovery time compared with ketamine.
Research Methodology
- The study was a randomized blinded experimental cross-over study, meaning the experiments were done randomly and the researchers didn’t know which horse received which anaesthetic.
- It involved six Thoroughbred horses which were anaesthetised three times, once with each anaesthetic agent (alfaxalone, ketamine and thiopental).
- The horses were premedicated with medetomidine and midazolam before administration of the main anaesthetics.
- The qualities of anaesthetic induction and recovery were scored on a scale of 1 (poor) to 5 (excellent). Induction time and recovery time were also recorded.
- Cardiopulmonary values (heart rate, respiratory rate, arterial blood pressures, and arterial blood gases) were recorded throughout anaesthesia.
- The data collected were analysed using nonparametric methods.
Research Findings
- The quality scores for anaesthetic induction and recovery were not significantly different amongst the three anaesthetic agents used.
- The induction time for ketamine was significantly longer than for alfaxalone and thiopental.
- The time to standing (recovery time) for alfaxalone and thiopental was significantly longer than that for ketamine.
- Cardiovascular values remained within acceptable levels throughout the anaesthesia period.
- The respiratory rate significantly decreased during anaesthesia for all three drugs; however, spontaneous breathing did not disappear, and arterial carbon dioxide (PaCO) values were maintained at approximately 50 mmHg.
Conclusion
- Alfaxalone, ketamine and thiopental have similar effects in relation to anaesthetic induction and recovery qualities as well as cardiopulmonary responses.
- However, alfaxalone and thiopental were found to prolong recovery time compared with ketamine.
Cite This Article
APA
Wakuno A, Aoki M, Kushiro A, Mae N, Kodaira K, Maeda T, Yamazaki Y, Ohta M.
(2016).
Comparison of alfaxalone, ketamine and thiopental for anaesthetic induction and recovery in Thoroughbred horses premedicated with medetomidine and midazolam.
Equine Vet J, 49(1), 94-98.
https://doi.org/10.1111/evj.12548 Publication
Researcher Affiliations
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
- Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki, Japan.
MeSH Terms
- Anesthetics / administration & dosage
- Anesthetics / pharmacology
- Animals
- Drug Therapy, Combination
- Horses
- Hypnotics and Sedatives / administration & dosage
- Hypnotics and Sedatives / pharmacology
- Ketamine / administration & dosage
- Ketamine / pharmacology
- Medetomidine / administration & dosage
- Medetomidine / pharmacology
- Midazolam / administration & dosage
- Midazolam / pharmacology
- Pregnanediones / administration & dosage
- Pregnanediones / pharmacology
- Premedication / veterinary
- Thiopental / administration & dosage
- Thiopental / pharmacology
Citations
This article has been cited 4 times.- Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature. Animals (Basel) 2021 Jun 14;11(6).
- Tokushige H, Kushiro A, Okano A, Maeda T, Ito H, Wakuno A, Nagata SI, Ohta M. Clinical evaluation of constant rate infusion of alfaxalone-medetomidine combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery. Acta Vet Scand 2018 Sep 4;60(1):50.
- Aoki M, Wakuno A, Kushiro A, Mae N, Kakizaki M, Nagata SI, Ohta M. Evaluation of total intravenous anesthesia with propofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in Thoroughbred horses undergoing castration. J Vet Med Sci 2017 Dec 22;79(12):2011-2018.
- Wakuno A, Maeda T, Kodaira K, Kikuchi T, Ohta M. Anesthetic management with sevoflurane combined with alfaxalone-medetomidine constant rate infusion in a Thoroughbred racehorse undergoing a long-time orthopedic surgery. J Equine Sci 2017;28(3):111-115.
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