Effects of medetomidine on doppler variables of major abdominal arteries in normal dogs

The purpose of this study was to evaluate the effects of medetomidine administration on the Doppler variables of abdominal arteries. The study population consisted of 20 healthy dogs. The haemodynamic effects of the medetomidine were defined using Doppler variables of the abdominal aorta, renal arteries, cranial mesenteric artery and celiac artery. The dogs were monitored continuously and different measurements were performed before medetomidine injection, at 10, 40 and 80 minutes after medetomidine medication and after atipamezole administration. Changes in the characteristic Doppler spectra of different vessels were more marked in the abdominal aorta, in which a greater reverse flow was found. There was a significant decrease in peak systolic velocity (PSV), end diastolic velocity (EDV), and mean velocity (MV) at ten minutes in every vessel studied and this effect persisted until atipamezole administration. Pulsatility index (PI) increased significantly in the abdominal aorta at ten minutes and persisted during the study until atipamezole administration. Resistive index (RI) did not vary significantly in any vessel. A significant decrease was found in flow volume of the abdominal aorta, the cranial mesenteric artery and the celiac artery at ten minutes, persisting until atipamezole administration. We conclude that medetomidine can be a good sedative in aiding sonographic evaluation of RI in all the abdominal vessels studied. On the other hand, the changes in other Doppler variables suggest that medetomidine administration causes significant hemodynamic differences between sedated and non-sedated dogs.