The source of coronary perfusion during partial bypass for extracorporeal membrane oxygenation (ECMO).

The proper siting of cannulas to return oxygenated blood to patients on long-term membrane oxygenator support is as yet undecided. This experimental study on adult sheep shows the problems of obtaining perfusion of the coronary arterial tree when blood is returned to the ascending aorta. Our 11 experiments demonstrate that the coronary arterial tree is perfused with blood ejected from the left ventricle except during very high bypass flows (85% bypass) or when the aortic valve is rendered incompetent.