In horses undergoing volatile anaesthesia, is recovery quality superior with sevoflurane compared to isoflurane?



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PICO question

In horses undergoing volatile anaesthesia, is recovery quality superior with the use of sevoflurane compared to isoflurane during the maintenance phase?


Clinical bottom line

The category of research question


Number and type of study designs reviewed

Seven papers were available for critical appraisal. Of the seven papers, six were prospective, randomised trials and four of these were of crossover design. Of the same seven papers, three were experimental and four were clinical.

Strength of evidence


Outcomes reported

Five out of seven critically appraised articles found that there was no clinically significant improvement in recovery quality following volatile anaesthesia with sevoflurane compared to isoflurane. Two of the seven articles did find improvement in recovery quality following the use of sevoflurane over isoflurane, but both studies were of crossover design, one of these studies used non-blinded evaluators and the second study used both unblinded and blinded evaluators and a recovery quality scoring scale that did not show interobserver reliability.


In healthy horses presented for elective surgical and diagnostic imaging procedures in a clinical setting, there is no significant difference in recovery quality following the use of sevoflurane or isoflurane for the maintenance phase.


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


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Brosnan, R. J., Steffey, E. P. & Escobar, A. (2012). Effects of hypercapnic hyperpnea on recovery from isoflurane or sevoflurane anesthesia in horses. Veterinary Anaesthesia and Analgesia. 39(4), 335–344. DOI:

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Vol. 8 No. 1 (2023): The first issue of 2023

Section: Knowledge Summaries

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