Comparison of the Cardiovascular Effects of Propofol, Thiopental and the Propofol-Thiopental Mixture in a Group of Healthy Dogs Premedicated with Hydromorphone

Abstract

The purpose of the investigation was to determine the differences in the cardiovascular performance in healthy dogs premedicated with hydromorphone and induced and kept with three different anesthetic protocols. Fifteen healthy dogs between one and six years of age were assessed, which did not have any heart diseases nor generated pain and with an anesthetic risk classified as ASA I. The patients were divided into three groups, and each was induced and kept in an anesthetic plan (stage III, plane 2) with a protocol according to the group they had been included in (thiopental, propofol or propofol-thiopental mixture). Each patient underwent echocardiography (fractional shortening and ejection fraction) and plasma lactate and blood pressure were measured by oscillometry. Measurements were made in three periods (T1, before premedication; T2, after premedication, and T3, post induction). A very significant difference was observed in the heart rate of patients anesthetized with propofol (<em>p = </em>0.0004), prone to bradycardia; blood pressure decreased in the propofol group; however, the difference was not significant (<em>p = </em>0.08). As for the other parameters (ejection fraction, fractional shortening and lactate), no differences were observed.