Abstract
The purpose of this study was to detect the cardiac output (CO) demand by analyzing patterns of changes in aortic characteristic impedance (ZO) as a basic research on the optimal control of artificial circulation. Through the experiments using mongrel dogs, CO demands were indicated by flexure points of ZO-CO curves. This ZO-CO relationship disappeared when phentolamine, an alpha sympathetic blockade, was administered. It was confirmed that the change of ZO against CO supply was controlled by the autonomic nervous system. Anaerobic threshold was less than CO demand. Results indicate that it is possible to detect the systemic blood flow demand during artificial circulation by the flexure point of the ZO-systemic blood flow curve.
