106 COMPARISON OF HEMODYNAMIC EFFECTS OF DOPAMINE AND DOBUTAMINE IN NEWBORN PUPPIES

The hemodynamic effects of Dobutamine (DOB) and Dopamine (DOPA) were compared in 12 term puppies, 3-5 weeks of age with a mean weight of 3.13 ± 1.16 kg. All dogs were anesthetized with 25 mg/kg of Nembutal. In 8 dogs Dobutamine was infused at 5, 10, 20 μg/kg/min followed by Dopamine at the same dose-rate and in the other four the order was reversed. Heart rate (HR), right atrial pressure (RaP), pulmonary artery pressure (PAP), aortic pressure (AoP), left ventricular pressure (LVP) and A-V differences (A-V diff) were measured and cardiac output (C.O.) calculated. Statistical significance was determined by paired ‘t’ and ‘F’ tests. The statistically significant differences observed were that: PAP increased with Dopamine as compared to Dobutamine at 10 and 20 μg/kg/min; RaP significantly increased with Dobutamine at 10 μg/kg/min and the increase in cardiac output at 20 μg/kg/min was significantly higher with Dobutamine than with Dopamine.