Figure 2.

Illustrations of various VA ECMO cannulations. Diagram (a) depicts a femoral vein-femoral artery peripheral cannulation. Retrograde outflow from a femoral arterial cannula competes with anterograde cardiac output ejected from the left ventricle. In this situation, poor lung function results in the ejection of deoxygenated blood (blue) from the left ventricle, which mixes with oxygenated blood (red) from the ECMO circuit. The point of mixing (dark red) is located at the base of the aortic root, but will vary depending on the patient's heart function and ECMO flow. Poor lung function and good myocardial function in the context of a femoral-femoral ECMO cannulation may result in upper body hypoxemia (see text). Diagram (c) shows central cannulation with venous inflow drawn from the right atrium and arterial outflow pumped into the ascending aorta.