Independence of changes in right atrial pressure and central venous pressure.

Dynamics of changes in right-atrial pressure and venous pressure measured in the inferior and superior vena cava at their orifices (central venous pressure) after bolus injection of 20 ml physiological saline or epinephrine (5.0 mg/kg) was studied in acute experiments on cats. The initial pressure in the right atrium was equal to that in caval veins. Pressor stimuli either increased or decreased the right atrial pressure, but always increased blood pressure in the caval veins. Moreover, right atrial pressure returned to the initial level more rapidly compared to that in caval veins. Our results suggest that the dynamics of the right-atrial pressure does not reflect the shifts in the central venous pressure.