COMPARISON OF CARDIOPULMONARY RESPONSES TO DETOMIDINE ADMINISTERED AS AN INTRAVENOUS STEADY-STATE INFUSION VS INTRAVENOUS BOLUS IN STANDING HORSES

Abstract

We compared the cardiopulmonary response to detomidine (DET) administered to two different groups of horses after IV steady-state infusion (n = 7) or IV bolus (n = 6) at similar plasma DET concentrations. Based upon previously reported kinetics, a computer predicted DET plasma concentrations and controlled an infusion pump which maintained steady-state arterial plasma DET for the infusion studies. These pharmacokinetics were used to estimate DET plasma concentrations at measurement times following IV bolus DET in the second group of horses. Cardiopulmonary measurements were made following 15 minutes of steady-state infusion and 30 minutes after IV bolus of DET. DET plasma concentration was estimated to be similar between A), 19 ng DET/ml plasma infusion and 30 minutes following an IV bolus dose of 10 γg DET/kg, (estimated plasma concentration 20.5 ng/ml), and B), 43 ng DET/ml plasma infusion and 30 minutes following an IV bolus of 20 γg DET/kg (estimated plasma concentration 42 ng/ml).