Fig. 1

Illustration of the ECMO technique and physiology of gas exchange (see main text for a detailed description). Venous blood is drawn via a central venous catheter inserted in the femoral vein, which is propelled at a set extracorporeal blood flow (ECBF) rate to a membrane oxygenator where gas exchange takes place. Gas with a user-adjusted fraction of O₂ enters the oxygenator in order to saturate the hemoglobin of the venous blood. CO₂ diffuses from the venous blood to the gas and leaves the oxygenator via an exit port. Heated and humidified oxygenated blood is then returned to the venous circulation via the jugular vein. V’O2 ECMO reflects the amount of oxygen delivered by the ECMO system and is depending on the ECBF and the oxygen content in the blood before (CvO_2INLET) and after (CvO_2OUTLET) the membrane oxygenator, respectively. White arrows in the subclavian veins and vena cava indicate native venous return; the oxygen content of the native system (CvO_2NATIVE) is mixed with the oxygenated blood from the ECMO system. The arterial oxygen content of the mixed blood (CvO₂) is described by Equation 2 and depends on the ratio of ECBF to cardiac output (CO₂). CO, cardiac output; CO₂, carbon dioxide; CvO₂, oxygen content in venous blood; ECBF, extracorporeal blood flow; O₂, oxygen