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Frontiers in veterinary science2021; 8; 603695; doi: 10.3389/fvets.2021.603695

Clinical Randomized Comparison of Medetomidine and Xylazine for Isoflurane Balanced Anesthesia in Horses.

Abstract: To assess drug plasma levels, preanesthetic sedation, cardiopulmonary effects during anesthesia and recovery in horses anesthetized with isoflurane combined with medetomidine or xylazine. Prospective blinded randomized clinical study. Sixty horses undergoing elective surgery. Thirty minutes after administration of antibiotics, flunixine meglumine or phenylbutazone and acepromazine horses received medetomidine 7 μg kg (group MED) or xylazine 1.1 mg kg (group XYL) slowly intravenously (IV) and sedation was assessed 3 min later. Anesthesia was induced with ketamine/diazepam and maintained with isoflurane in oxygen/air and medetomidine 3.5 μg kg h or xylazine 0.69 mg kg h. Ringer's acetate 10 mL kg h and dobutamine were administered to maintain normotension. All horses were mechanically ventilated to maintain end-tidal carbon dioxide pressures at 45 ± 5 mmHg (5.3-6.7 kPa). Heart rate (HR), invasive arterial blood pressures, inspired and expired gas compositions, pH, arterial blood gases, electrolytes, lactate and glucose were measured. For recovery all horses received intramuscular morphine 0.1 mg kg and medetomidine 2 μg kg or xylazine 0.3 mg kg IV. Recovery was timed and scored using three different scoring systems. Plasma samples to measure medetomidine and xylazine concentrations were collected at predetermined timepoints. Repeatedly measured parameters were analyzed using a two-way repeated-measures analysis of variance for differences between groups and over time; < 0.05 was considered statistically significant. Mean arterial blood pressures (MAP) stayed within normal ranges but were higher ( = 0.011) in group XYL despite significant lower dobutamine doses ( = 0.0003). Other measured parameters were within clinically acceptable ranges. Plasma levels were at steady state during anesthesia (MED 2.194 ± 0.073; XYL 708 ± 18.791 ng mL). During recovery lateral recumbency (MED 42.7 ± 2.51; XYL 34.3 ± 2.63 min; = 0.027) and time to standing (MED 62.0 ± 2.86; XYL 48.8 ± 3.01 min; = 0.002) were significantly shorter in group XYL compared to group MED. Recovery scores did not differ significantly between groups. In horses anesthetized with isoflurane and medetomidine or xylazine, xylazine maintained higher MAP, reduced the dobutamine consumption and recovery time, whilst overall recovery quality was unaffected.
Copyright © 2021 Wiederkehr, Barbarossa, Ringer, Jörger, Bryner and Bettschart-Wolfensberger.
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Publication Date: 2021-04-20 PubMed ID: 33959647PubMed Central: PMC8093396DOI: 10.3389/fvets.2021.603695Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study looks into a comparison of effects between two drugs, Medetomidine and Xylazine, when used in combination with Isoflurane for anesthesia during horse surgery. It mainly focuses on the effects of the two drugs on sedation, cardiopulmonary actions, and recovery in horses.

Study Design

  • The research is a prospective blinded randomized clinical study, involving 60 horses that were set to undergo elective surgery.
  • Both drugs were applied intravenously, 30 minutes after the administration of antibiotics, flunixine meglumine or phenylbutazone and acepromazine, and sedation was observed 3 min later.
  • Anesthesia was induced with ketamine/diazepam and maintained with isoflurane in oxygen/air and either medetomidine or xylazine. To maintain normotension, Ringer’s acetate and dobutamine were applied.
  • All horses were mechanically ventilated to maintain end-tidal carbon dioxide pressures at optimal levels. Different parameters were measured including heart rate, arterial blood pressures, pH, electrolytes, lactate and glucose among others.
  • During recovery, all horses received intramuscular morphine and either medetomidine or xylazine. Recovery was timed and scored using three different scoring systems.
  • Plasma samples were collected at predetermined timepoints to measure the concentrations of medetomidine and xylazine.

Results

  • Mean arterial blood pressures remained in normal ranges but were higher in the xylazine group even though they received significantly lower dobutamine doses.
  • All other parameters were in the clinically acceptable ranges.
  • During anesthesia, plasma levels were steady for both groups.
  • Different measures of recovery time including lateral recumbency and time to standing were found to be significantly shorter in the xylazine group.
  • However, recovery scores did not differ significantly between the groups.

Conclusions

  • The findings suggest that using xylazine with isoflurane for anesthesia in horses provides better results than medetomidine. Xylazine was found to maintain higher mean arterial blood pressures, reduce the consumption of dobutamine and shorten recovery time.
  • However, the overall recovery quality, judged by recovery scores, was similar in both groups.

Cite This Article

APA
Wiederkehr A, Barbarossa A, Ringer SK, Jörger FB, Bryner M, Bettschart-Wolfensberger R. (2021). Clinical Randomized Comparison of Medetomidine and Xylazine for Isoflurane Balanced Anesthesia in Horses. Front Vet Sci, 8, 603695. https://doi.org/10.3389/fvets.2021.603695

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 8
Pages: 603695
PII: 603695

Researcher Affiliations

Wiederkehr, Alexandra
  • Section Anesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Barbarossa, Andrea
  • Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy.
Ringer, Simone K
  • Section Anesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Jörger, Fabiola B
  • Section Anesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Bryner, Marco
  • Clinic for Equine Surgery, Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Bettschart-Wolfensberger, Regula
  • Section Anesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Citations

This article has been cited 5 times.
  1. Kälin I, Henze IS, Ringer SK, Torgerson PR, Bettschart-Wolfensberger R. Comparison of Recovery Quality Following Medetomidine versus Xylazine Balanced Isoflurane Anaesthesia in Horses: A Retrospective Analysis. Animals (Basel) 2021 Aug 19;11(8).
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  2. Cunneen A, Pratt S, Perkins N, McEwen M, Truchetti G, Rainger J, Farry T, Kidd L, Goodwin W. Total Intravenous Anaesthesia with Ketamine, Medetomidine and Midazolam as Part of a Balanced Anaesthesia Technique in Horses Undergoing Castration. Vet Sci 2021 Jul 26;8(8).
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