Is isoflurane safer than halothane in equine anaesthesia? Results from a prospective multicentre randomised controlled trial.
Abstract: Approximately 1 in 100 horses suffer unexpectedly from anaesthetic-related death. Identification and use of the safest anaesthetic drugs should support this aim. Experimental evidence has suggested that isoflurane should be a safer maintenance agent in equine anaesthesia than halothane. Objective: The death rate would be reduced in horses being maintained with isoflurane compared to halothane. Methods: A multicentre randomised controlled trial was undertaken to compare the effects of isoflurane and halothane for maintenance of equine anaesthesia for all types of operation. Data were analysed from 8242 horses in which anaesthesia was maintained with either halothane or isoflurane using mixed effects logistic regression models. Results: No overall benefit of either drug was detected. However, although not part of the primary hypothesis, data showed that the overall death rate was significantly reduced in horses age 2-5 years with isoflurane and that death from cardiac arrest was also reduced with isoflurane, particularly in high risk cases. Conclusions: Halothane remains an acceptable anaesthetic for maintenance of anaesthesia in horses, but isoflurane may be safer in the young horse and in high risk cases.
Publication Date: 2004-02-06 PubMed ID: 14756374DOI: 10.2746/0425164044864723Google Scholar: Lookup
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- Clinical Trial
- Comparative Study
- Journal Article
- Multicenter Study
- Randomized Controlled Trial
- Research Support
- Non-U.S. Gov't
Summary
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The research paper discusses a study comparing the safety of isoflurane and halothane in equine anesthesia, finding no significant difference in safety between the two in general. However, the use of isoflurane might be safer for horses aged between 2 to 5 years old and those at high risk.
Objective and Methods
- The objective of the study was to ascertain if a reduction in death rates could be accomplished by maintaining anesthesia in horses using isoflurane instead of halothane.
- The researchers conducted a multicentre randomised controlled trial comparing the effects of isoflurane and halothane in maintaining equine anesthesia during various types of surgical procedures.
- Data were collected and analysed from 8,242 horses. The anesthesia in these horses was maintained with either halothane or isoflurane, and the results were analysed using mixed-effects logistic regression models.
Results
- The results showed no significant disparity in the overall effectiveness of the two drugs in anesthesia maintenance.
- Despite this, the data revealed that the overall death rate was significantly lower in horses aged between two and five years when isoflurane was used instead of halothane. There was a decrease in death rates from cardiac arrest with use of isoflurane, particularly in high-risk cases.
Conclusion
- The findings of the study concluded that both isoflurane and halothane are acceptable as anesthetics for the maintenance of anesthesia in horses.
- However, isoflurane might be a safer choice for young horses, particularly those aged between two and five years, and for horses classified as high risk.
Cite This Article
APA
Johnston GM, Eastment JK, Taylor PM, Wood JL.
(2004).
Is isoflurane safer than halothane in equine anaesthesia? Results from a prospective multicentre randomised controlled trial.
Equine Vet J, 36(1), 64-71.
https://doi.org/10.2746/0425164044864723 Publication
Researcher Affiliations
- Department of Clinical Veterinary Medicine, University of Cambridge, Cambridgeshire CB3 0ES, UK.
MeSH Terms
- Age Factors
- Anesthesia Recovery Period
- Anesthesia, Inhalation / mortality
- Anesthesia, Inhalation / veterinary
- Anesthetics, Inhalation / pharmacology
- Animals
- Female
- Halothane / pharmacology
- Horses / physiology
- Horses / surgery
- Isoflurane / pharmacology
- Logistic Models
- Male
- Prospective Studies
- Risk Factors
- Safety
- Survival Analysis
Citations
This article has been cited 12 times.- Hewitt-Dedman CL, O'Neill HD, Bladon BM. Arthroscopic removal of palmar intermediate carpal bone fracture fragments in four horses using a transthecal approach through the carpal flexor tendon sheath. Vet Surg 2022 Aug;51(6):929-939.
- Gozalo-Marcilla M, Bettschart-Wolfensberger R, Johnston M, Taylor PM, Redondo JI. Data Collection for the Fourth Multicentre Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4) Study: New Technology and Preliminary Results. Animals (Basel) 2021 Aug 30;11(9).
- Vermedal H, Valverde A, Sears W. Effect of anesthesia duration on the quality of recovery in horses undergoing elective and emergency surgeries using the same anesthetic protocol. Can J Vet Res 2021 Jul;85(3):193-200.
- 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).
- Gozalo-Marcilla M, Redondo JI, Johnston M, Taylor P, Bettschart-Wolfensberger R. CEPEF4: update and plan. Vet Anaesth Analg 2020 Sep;47(5):724-725.
- Laurenza C, Ansart L, Portier K. Risk Factors of Anesthesia-Related Mortality and Morbidity in One Equine Hospital: A Retrospective Study on 1,161 Cases Undergoing Elective or Emergency Surgeries. Front Vet Sci 2019;6:514.
- Fahlman Å, Edner A, Wenger S, Foggin C, Nyman G. Pulmonary gas exchange and acid-base status during immobilisation of black rhinoceroses (Diceros bicornis) in Zimbabwe. J S Afr Vet Assoc 2016 Dec 2;87(1):e1-e9.
- Mullen KR, Furness MC, Johnson AL, Norman TE, Hart KA, Burton AJ, Bicahlo RC, Ainsworth DM, Thompson MS, Scrivani PV. Adverse reactions in horses that underwent general anesthesia and cervical myelography. J Vet Intern Med 2015 May-Jun;29(3):954-60.
- Ayala I, Rodríguez MJ, Aguirre C, Buendía AJ, Belda E, Laredo FG. Postanesthetic brachial triceps myonecrosis in a Spanish-bred horse. Can Vet J 2009 Feb;50(2):189-93.
- Edner AH, Nyman GC, Essén-Gustavsson B. Metabolism before, during and after anaesthesia in colic and healthy horses. Acta Vet Scand 2007 Nov 15;49(1):34.
- Henderson ARP, Valverde A, Koenig J, Sears W. Effects of anesthetic protocol, procedure, and recovery stall and interval on the quality of recovery in repeatedly anesthetized horses. Can J Vet Res 2025 Jan;89(1):17-25.
- Fesmire CC, Peal B, Ruff J, Moyer E, McParland TJ, Derks K, O'Neil E, Emke C, Johnson B, Ghosh S, Petrella RA, DeWitt MR, Prange T, Fogle C, Sano MB. Investigation of integrated time nanosecond pulse irreversible electroporation against spontaneous equine melanoma. Front Vet Sci 2024;11:1232650.
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