CARDIOPULMONARY EFFECTS OF MEDETOMIDINE IN SHEEP AND IN PONIES

Medetomidine was administered intravenously to six sheep at 5, 10 and 20 mu g kg(-1) and to one horse and four ponies at 5 and 10 mu g kg(-1 ). In both species medetomidine resulted in significant decreases in h eart rate and cardiac output and, initially, in an increase in arteria l blood pressure. In the ponies this increase in blood pressure was fo llowed by a significant and prolonged decrease, but in the sheep the s econdary decrease in blood pressure was not statistically significant. In the sheep, the three doses of medetomidine resulted in profound an d significant decreases in arterial oxygen tensions, which were signif icantly dose related, bur in the ponies the arterial blood oxygen tens ions were not significantly decreased. In both species medetomidine ca used a small but significant increase in arterial blood carbon dioxide tensions.