Circulation research
-
Circulation research · Apr 1976
Effect of thoracic blood volume changes on steady state cardiac output.
We have investigated the extent to which shifts of blood volume out of or into the thoracic region influence the steady state cardiac output. The systemic circulation of anesthetized dogs was replaced with an artificial circuit which stimulated the pertinent mechanical characteristics of an intact circulation. As in the normal animal, the steady state venous return was proportional to the pressure gradient for venous return (i.e, mean systemic minus right atrial pressure). ⋯ Our results indicate that the heart-lung compartment contains a significant volume which is under cardiac control. In addition to being able to alter the right atrial pressure, the heart can modulate the steady state cardiac output by adjusting the mean systemic pressure. To this degree the heart can adjust its own venous return.