Extracorporeal membrane oxygenation (ECMO) is a method of supporting respiratory or cardio-respiratory failure. Oxygenation of the blood is performed outside the body across a membrane. When both an artery and vein are cannulated, cardiac support is possible. Usually the carotid artery and the internal jugular vein are cannulated to access the superior vena cava/right atrium and the aortic arch. If only veno-venous ECMO (as opposed to veno-arterial) is desired, then a dual lumen catheter can be placed in the venous system. Minimal ventilation of the lungs is performed and so the lungs may become opaque on subsequent radiographs.