The numerical study on the effects of cardiac function on the aortic oxygen distribution.

Although venoarterial extracorporeal membrane oxygenation (VA-ECMO) was widely used in clinical practice, the effects of cardiac output on the aortic oxygen distribution were still unclear. Hence, the present study aims to evaluate the effect of cardiac function on the aortic oxygen distribution under VA-ECMO support. A novel model, combining computational fluid dynamics, multiphase fluid approach, and oxygen transport theory together, was established. According to the clinical practice, four cardiac output conditions, including 0, 1, 2, and 2.5 L/min, were designed. The results demonstrated that the proposed method could accurately calculate the distribution of oxygen in the aorta. Moreover, the aortic oxygen distribution was significantly regulated by the local blood flow pattern. The deoxygenated blood flow and oxygenated blood flow met at the aortic arch and formed the so-called oxygenshed phenomenon. Along with the cardiac output increase, the oxygenshed was moved from the proximal of the aortic arch to the descending aorta. Meanwhile, the oxygen contents in the brachiocephalic artery and left common carotid artery were reduced along with the increase of cardiac output. The study could provide much useful information on the oxygen distribution in the aorta to surgeons and operators of VA-ECMO. Graphical abstract The results showed the deoxygenated blood and oxygenated blood met at the aortic arch and formed the so-called "oxygenshed" phenomenon. This phenomenon is consistent with the phenomenon called "watershed".