Influence of detomidine and xylazine on spleen dimensions and on splenic response to epinephrine infusion in healthy adult horses.

The research investigates the effects of the drugs detomidine and xylazine on the spleen of adult horses, and their interaction with a following infusion of epinephrine. The study finds neither detomidine nor xylazine hinder the spleen’s ability to contract after an epinephrine infusion, indicating the efficiency of epinephrine in treating large colon displacement isn’t impeded by prior treatment with these drugs, although further study is necessary.

Methodology

• The research used a randomized non-blinded crossover experiment, involving six healthy adult mares.
• The mares were given an intravenous infusion of epinephrine at a rate of 1 μg kg(-1) minute(-1) over 5 minutes. This was done one hour after they were given an intravenous dose of either detomidine (0.01 mg kg(-1)), xylazine (0.5 mg kg(-1)), or no drug at all (control group).
• There was a withdrawal period of at least 7 days between each experiment.
• The splenic length and thickness, as well as packed cell volume (PCV), were measured prior to sedation, 30 minutes later, and at 5-minute intervals from the start of the epinephrine infusion until 40 minutes later.
• Changes from the baseline and comparison of treatment effects were determined through the use of two-way ANOVA for repeated measures. Any change with a p-value of less than 0.05 was considered significant.

Results

• Following detomidine administration, there was a noticeable increase in spleen length and a decrease in PCV compared to baseline readings.
• The epinephrine infusion further resulted in a significant reduction in spleen length and thickness and an increase in PCV. These changes were irrespective of whether the horse had been pre-treated with detomidine or xylazine.

Conclusions

• Upon administering detomidine, there is a visible increase in spleen length as viewed through sonography.
• The study revealed that neither detomidine nor xylazine interfered with the spleen’s ability to contract subsequent to the administration of an epinephrine infusion.
• However, the study suggests the need for further investigations, particularly focusing on the use of different drug doses and varying time intervals between administrations, to more thoroughly understand the interaction between these drugs in the application of medical treatment for left dorsal displacement of the large colon in horses.