Fig. 1

Schematic diagram of the retrograde blood flow from VA-ECMO against the antegrade blood flow pumped by the heart. Legend: The red diamond stands for the ECMO oxygenator, LV for the left ventricle, red vessels for arteries, red lines and arrows for the direction of ECMO oxygenated blood flow, and the blue lines and arrows for the direction of the pumping blood flow from the heart. The black dotted line represents the intersection plane of blood flow, and the black * indicates the IPPaO₂. The intersection plane is located in the front of the opening of the brachiocephalic trunk when the cardiac function is poor (a); When the cardiac function gradually improves, the self-pumping blood flow rate increases, and the intersection plane moves to the distal part of the brachiocephalic trunk opening (b).