Venoarterial ECMO with the addition of a venous reinfusion limb (venoarteriovenous ECMO)

This image depicts typical circuitry of V-A ECMO with an additional venous reinfusion cannula (or V-V ECMO with an additional arterial reinfusion cannula). Blood is drained from a central vein (blue) and reinfused into the femoral artery (red; lower limb of the Y connector) and right atrium (red; upper limb of the Y connector). The arterial reinfusion cannula provides hemodynamic and gas exchange support, but when there is residual native cardiac output and impaired native gas exchange, the proximal branches of the aorta may be inadequately oxygenated. The venous reinfusion cannula provides oxygenated blood to the right atrium, which is then propagated through the native cardiac circulation and may improve delivery of well-oxygenated blood to the proximal branches of the aorta. The blender mixes air and oxygen to set the fraction of delivered oxygen that reaches the membrane. During V-V ECMO for respiratory failure, development of concomitant cardiogenic shock may necessitate the addition of an arterial limb, resulting in V-VA ECMO, which effectively results in the same configuration as V-AV ECMO. The inset shows the potential for recirculation of the reinfused, oxygenated blood, which instead of flowing into the right atrium, pulmonary artery, and then to the systemic circulation, may flow towards the drainage cannula and re-enter the circuit (purple arrow).