ECMO Configurations and Cannulation in Adult Patients

Extracorporeal membrane oxygenation (ECMO), a form of extracorporeal life support (ECLS), represents a life-saving intervention in patients with cardiac and/or respiratory failure not responding to medical therapy. Blood is drained from a central vein (V), pumped through a membrane oxygenator for oxygenation and CO2 removal, and ultimately returned into a central vein or artery (A). Veno-arterial (V-A) ECMO is primarily used for patients in cardiogenic shock and provides both hemodynamic and respiratory support. V-A ECMO can limit or prevent secondary end-organ damage and allow time for myocardial recovery while a decision is made for the best definitive treatment. Conventional peripheral V-A ECMO, that is, return via femoral artery, carries the risks of differential oxygenation with upper body hypoxemia and extremity ischemia. Veno-venous (V-V) ECMO can rescue patients with the most severe respiratory failure but does not provide hemodynamic support. V-V ECMO allows for lung rest in patients who otherwise would receive potentially injurious ventilator support. Both V-A and V-V ECMO are invaluable, life-saving tools in patients who are failing maximum medical therapy.