Effect of detomidine on postural sway in horses

The objective of this study was to apply postural sway analysis to measure balance deficits after intravenous administration of detomidine. Six healthy horses were treated intravenously with detomidine (10 μg kg −1 , 20 μgkg −1 ) and saline in random order, with three days between treatments. Postural sway was measured immediately after administration and at 15 min intervals until 120 min had elapsed. Horses stood squarely with all four hooves on a force platform, while the location of the centre of pressure (COP) was recorded continuously for 10 s at 1000 Hz. Five 10 s recordings were analysed and average values calculated for mediolateral COP range of motion, craniocaudal COP range of motion, mean COP radius, COP area and mean COP velocity. All COP variables increased immediately after sedation, but generally returned to normal limits within 15 and 30 min of detomidine administration at 10 and 20 μg kg −1 , respectively. The head was lowered for at least 90 min after administration. Balance is affected by detomidine and normal balance is regained later after a higher dose. Procedures requiring balance should not be performed within 15–30 min of detomidine administration. COP variables are a good indicator of the effect of sedation on postural sway, but head position is not.