A 60-year-old man with ARDS is on VV-ECMO. The ECMO circuit blood flow is 4.5 L/min but the patient's native cardiac output is 7 L/min. What proportio...

Question

A 60-year-old man with ARDS is on VV-ECMO. The ECMO circuit blood flow is 4.5 L/min but the patient's native cardiac output is 7 L/min. What proportion of his blood is being oxygenated by the ECMO circuit, and what clinical implication does this have?

Accepted Answer

Approximately 64% (4.5/7) - the remaining 36% bypasses the ECMO circuit and relies on native lung function for gas exchange; this means the patient's arterial PaO2 is a blend of fully oxygenated circuit blood and poorly oxygenated native lung blood

Answer

100% - all blood passes through the circuit

Answer

Only 10% of blood is oxygenated by ECMO

Answer

ECMO blood flow has no relationship to oxygenation fraction

Answer

The native cardiac output is irrelevant during VV-ECMO

uk-fficm MCQ (SBA): VV-ECMO Physiology

A 60-year-old man with ARDS is on VV-ECMO. The ECMO circuit blood flow is 4.5 L/min but the patient's native cardiac output is 7 L/min. What proportion of his blood is being oxygenated by the ECMO circuit, and what clinical implication does this have?