Two-site venovenous extracorporeal membrane oxygenation

This image depicts typical circuitry of V-V ECMO using a 2-site approach. Blood is drained from a central vein through a cannula (blue arrows), pumped through the oxygenator (ie, membrane lung) by a centrifugal pump, and reinfused back into a central vein (red arrows). A typical site for the drainage cannula is the femoral vein with its tip situated at or above the right atrial-inferior vena cava junction and the reinfusion cannula placed in an internal jugular vein with its tip in the superior vena cava. The blender mixes air and oxygen to set the fraction of delivered oxygen that reaches the membrane. The inset shows the potential for recirculation of the reinfused, oxygenated blood, which instead of flowing into the systemic circulation, may flow toward the drainage cannula and re-enter the circuit (purple arrow). Retracting the drainage cannula, decreasing flow, or using a single-site approach may mitigate recirculation. Refer to UpToDate content on venovenous extracorporeal membrane oxygenation for other configurations.