Arterial oxygen pressure during veno-venous extracorporeal membrane oxygenation may be increased by advancing the tip of the drainage cannula into the superior vena cava: a case report

A simple and robust method for veno-venous extracorporeal membrane oxygenation (V–V ECMO) involves a drainage cannula into the inferior vena cava via the femoral vein (FV) and a reinfusion cannula into the right atrium (RA) via the internal jugular vein (IJV) (F–J configuration). However, with this method, the arterial oxygen (PaO₂) is said to remain below 100 mmHg. Since recently, in our ICU, to prevent drainage failure, we apply a modification from the commonly practiced F–J configuration by advancing the tip of the drainage cannula inserted via the FV into the superior vena cava (SVC) and crossing the reinfusion cannula inserted via the IJV in the RA (F(SVC)–J(RA) configuration). We experienced that this modification can be associated with unexpectedly high PaO₂ values, which here we investigated in detail. Veno-arteriovenous ECMO was induced in a 65-year-old male patient who suffered from repeated cardiac arrest due to acute respiratory distress syndrome. His chest X-ray images showed white-out after lung rest setting, consistent with near-absence of self-lung ventilation. Cardiac function recovered and the system was converted to F(SVC)–J(RA) configuration, after which both PaO₂ and partial pressure of pulmonary arterial oxygen values remained high above 200 mmHg. Transesophageal echocardiography could not detect right-to-left shunt, and more efficient drainage of the native venous return flow compared to common F–J configuration may explain the increased PaO₂. Although the F(SVC)-J(RA) configuration is a small modification of the F–J configuration, it seems to provide a revolutionary improvement in the ECMO field by combining robustness/simplicity with high PaO₂ values.