Arterial impedance during the cardiopulmonary bypass using oscillated blood flow

The blood perfusion of systemic circulation is influenced by the physical characteristics of artery. Several investigations proposed that the physical parameters of vessels are determined by some factors which are neurological factors, hormonal factors, physical properties of artery and so on. In this study, the arterial impedance was estimated because it may express the conditions of vessels. To examine the change of arterial impedance according to the blood flow pattern, the typical sine-wave blood flow, which was called oscillated flow, was used for the total cardiopulmonary bypass (CPB), because it can be considered for the most simple pulsatile flow. CPB using oscillated blood flow was performed for eight adult goats in acute experiments. The total systemic flow were controlled to maintain about 80ml/min. Aortic pressure, central venous pressure and systemic flow were measured. And the total peripheral resistance and arterial impedance were calculated to evaluate the reaction of vessels during the CPB. From this study, it was shown that arterial impedance was fluctuated according to the change of flow frequency. So the vascular reaction to the change of blood flow velocity might be characterized during oscillated blood flow.