A comparison of recovery times and characteristics with sevoflurane and isoflurane anaesthesia in horses undergoing magnetic resonance imaging.

The research study examined the recovery times and quality of horses undergoing magnetic resonance imaging (MRI) when administered either sevoflurane or isoflurane anaesthesia following a standard intravenous induction technique. The study found no significant differences in recovery times or quality between the two anaesthesia methods.

Research Method

• The study was a prospective, randomized, and blinded clinical trial involving 100 ASA I/II horses that were undergoing MRI.
• The horses were pre-medicated with intravenous acepromazine and romifidine, followed by induction of anaesthesia using diazepam and ketamine.
• The horses were randomly distributed into two groups; one group received sevoflurane and the other received isoflurane in oxygen.
• The temperament of the horses before sedation was subjectively scored, along with the quality of sedation, induction and maintenance, and the depth of anaesthesia upon entering the recovery area.

Data Collection and Analysis

• The recoveries were videotaped and scored by an observer who was not aware of the treatment received.
• Important times were recorded, including the time to the first movement, time to head lift, time until the horse could recline on its breastbone (sternal recumbency), and the time until the horse was able to stand.
• The number of attempts the horse needed to achieve sternal recumbency and standing were also recorded.
• The data was analyzed using Student t-test or Mann-Whitney U-test, while the correlation between subjective recovery score and other relevant variables was assessed with the Spearman Rank correlation coefficient and linear regression modelling.

Research Findings

• Out of the 100 initial horses, 77 entered the final analysis, with 38 having received isoflurane and 39 sevoflurane.
• Variables such as body mass, age, and duration of anesthesia did not significantly differ between both groups.
• There were no differences between the two groups in terms of recovery times, scoring, or the number of attempts needed to achieve sternal recumbency and standing positions.
• Weak, but significant, correlations were found between the subjective recovery score and both temperament and time spent in sternal recumbency for the pooled data from both groups.

Conclusions

• The study concluded that no differences in recovery times or quality could be detected following the use of either isoflurane or sevoflurane anaesthesia after intravenous induction.
• The findings of the study suggest that sevoflurane does not offer any clear advantage over isoflurane in terms of recovery from a standard intravenous induction technique in horses not undergoing surgery.