A blinded crossover study design to evaluate midazolam as an adjunct for equine standing sedation for routine oral examinations.

This study investigates the impact of using midazolam, a sedative, as part of a procedure for sedating horses for routine oral exams, utilizing a randomized and blinded crossover design. It concluded that, while there were no significant differences in measures of sedation, some aspects such as decreased tongue movement and acceptance of speculum indicated potential benefits.

Objective and Methodology

• The central objective of the research was to assess the efficacy of incorporating midazolam into the standard protocol for equine standing sedation during routine oral examinations. Using a blinded crossover study design, two treatments were compared: the administration of midazolam and a placebo (saline).
• Twelve horses were selected for the study, each undergoing two examinations at an interval of seven days. These horses were randomly assigned to receive either midazolam or saline intravenously. Five minutes later, further sedatives were administered, this being detomidine and butorphanol, and the horses were positioned in standing stocks for the examination.

Examination and Analysis of Sedation Indicators

• A veterinarian, who was not aware of the treatment protocol, used a scoring system to evaluate various factors related to sedation and responsiveness of the horse, such as the degree of ataxia, acceptance of the speculum, tongue movement, resistance to palpation, and eye appearance compared to the grimace score.
• During each examination, the blinded practitioner could opt to administer more sedatives, again detomidine and butorphanol, if required for ensuring a safe examination.
• For the subsequent examination, horses were given the opposite treatment (i.e., if they received midazolam in the first instance, they would receive saline, and vice versa).

Statistical Analysis and Results

• Data collected during the examinations were statistically analyzed using a repeated measures mixed effects model. The treatment was considered as a fixed effect while the horse and the interaction between horse and treatment were treated as random effects.
• The results of the study did not show any significant differences in the scores that measured sedation, regardless of whether midazolam or saline was used. This lack of statistical significance was consistent across different treatment groups and within individual horses.

Conclusions and Implications

• Despite no major differences being statistically proven, the study found some observable trends favoring the use of midazolam. There was a shown reduction in tongue movement and less resistance to speculum acceptance in the midazolam group.
• The researchers concluded that midazolam could potentially be beneficial in routine oral examinations and other standing procedures for horses – providing these results can be externally validated in further studies – as it did not result in any apparent negative side effects.