The position of the inferior vena cava-right atrium junction on simple radiography: implication for optimal veno-venous extracorporeal membrane oxygenation cannula tip position

Extracorporeal membrane oxygenation (ECMO) is increasingly used for patients with respiratory and/or cardiac failure (1). Among the factors affecting effective oxygenation in veno-venous (V-V) ECMO, the amount of recirculation can be affected by cannula position (2). Therefore, adequate tip position of V-V ECMO cannula is important. In the V-V ECMO with classic feature, drainage cannula tip is positioned at or just distal to the inferior vena cava-right atrium junction (IRJ) and a return cannula is positioned at the right atrium-superior vena cava junction or within the right atrium (RA) (3). And this position is confirmed by echocardiography in general, which is operator-dependent and is inconvenient for the patients when performed (4)