Fig. 1

Outline of the ECMO model. Blood flow shown in blue. \( {\dot{Q}}_T \) is cardiac output, \( {\dot{Q}}_L \) is blood flow to lung compartment, \( {\dot{Q}}_S \) is pulmonary shunt blood flow, \( {\dot{Q}}_{EC} \) is blood flow to the extracorporeal blood circuit,\( {\dot{Q}}_{oxy} \) is blood flow to the ideal oxygenator compartment that participates in gas exchange, while \( {\dot{Q}}_{S\ EC} \) is shunt blood flow that does not participate in gas exchange. \( {\dot{Q}}_{EC} \) includes both recirculated blood flow (\( {\dot{Q}}_{RC}\Big) \) and part of the “mixed venous” blood flow from the tissues. Gas flows shown in green. \( {\dot{V}}_A \) is alveolar ventilation, \( {\dot{V}}_D \) is dead space ventilation, \( {\dot{V}}_E \) is expired minute ventilation, \( {\dot{V}}_{\mathrm{SWEEP}} \) is sweep gas flow to the oxygenator, oxygenator and lung are modelled as ideal lung compartments. Tissues consume O₂ and produce CO₂. “Arterial” blood perfuses the tissues, and “Mixed Venous” blood drains from the tissues. “Pulmonary Arterial” blood is a mixture of blood that has passed through the extracorporeal circuit, and blood that has not