Carotid arterial impedance during oscillated blood flow

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 neurological factors, hormonal factors, and physical properties of arteries among others. In this study, arterial impedance was estimated because it may express the condition of vessels. To examine the change of arterial impedance according to the blood flow pattern, the typical sine wave blood flow (oscillated flow) was used during total cardiopulmonary bypass (CPB) because it is considered the most simple pulsatile flow. CPB using oscillated blood flow was performed in acute experiments on adult goats. Total systemic flow was controlled to remain at approximately 80 ml/min. Carotid arterial flow, aortic pressure, central venous pressure, and systemic flow were measured. Total peripheral resistance, carotid arterial resistance, systemic impedance, and carotid arterial impedance were calculated to evaluate blood flow distribution during CPB. This study suggested that the parameters of carotid arterial blood flow changed according to the change of flow frequency during oscillated blood flow. This change may occur because arterial impedance was influenced by flow frequency; therefore, the blood flow of the carotid artery was significantly changed according to the change of the frequency component of blood flow.