Cardiac performance in conscious healthy dogs during dobutamine infusion.

The aim of this study was to determine the cardiac performance of conscious healthy dogs during stimulation with dobutamine. Eight healthy unsedated beagle dogs were used. Cardiac output was measured by the thermodilution technique and blood pressures by extravascular pressure transducers. Dobutamine challenge at a dosage ranging from 27.5 to 50 micrograms kg-1 min-1 induced a significant rise in cardiac power index (CPI), cardiac index (CI), stroke index (SI) and heart rate (HR) and a significant decrease in pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR). The highest CPI was 2.05 times greater than its basal resting value. The CI was primarily responsible for this increase in CPI. The SI and HR contributed approximately 55 per cent and 45 per cent respectively of the maximal increase in CI.