Application of prone position in hypoxaemic patients supported by veno-venous ECMO

Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) is an advanced respiratory care therapy allowing replacement of pulmonary gas exchange. Despite VV-ECMO support, some patients may remain hypoxaemic. A possible therapeutic procedure for these patients is the application of prone positioning.

The primary aim of the present study was to investigate modification of the PaO₂/FiO₂ ratio, in VV-ECMO patients with refractory hypoxaemia. The secondary aim was to evaluate the safety and feasibility of prone positioning for patients with severe Adult Respiratory Distress Syndrome supported by ECMO.

We retrospectively reviewed the electronic records and charts of all patients supported by VV-ECMO who experienced at least one pronation. Complications related with prone positioning were also recorded. First PaO₂/FiO₂ ratio was analysed during four different time steps: before pronation, one hour after pronation, at the end of pronation and one hour after returning to supine.

A total of 45 prone positioning manoeuvers were performed in 14 VV-ECMO patients from November 2009 to November 2014. The median duration of prone positioning cycles was 8 hours (IQR 6-10). No accidental dislodgement of intravascular lines, endotracheal tubes, chest tubes or a decrease in ECMO blood flow was observed. During the first prone positioning for each patient, the median PaO₂/FiO₂ ratio recorded was 123 (IQR 82-135), 152 (93-185), 149 (90-186) and 113 (74-182), during PRE-supine step, 1 h-prone positioning step, END-prone positioning step, and POST-supine step respectively.

The application of prone positioning during VV-ECMO has shown to be a safe and reliable technique when performed in a recognised ECMO centre with the appropriately trained staff and standard procedures.