What is the niche for extracorporeal membrane oxygenation in severe acute respiratory distress syndrome?

PURPOSE OF REVIEW: This article reviews the results of case series and trials which evaluated venovenous extracorporeal membrane oxygenation (VV-ECMO) for severe respiratory failure. Potential indications of the technique in this setting are discussed.

RECENT FINDINGS: Major technological improvements in extracorporeal membrane oxygenation (ECMO) machines and the positive results of the conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR) trial have reignited interest in VV-ECMO in patients with severe acute respiratory distress syndrome (ARDS) and persistent hypoxemia or hypercarbia on conventional mechanical ventilation. The technique has also been successfully used as a rescue therapy for the most severe ARDS cases associated with the recent Influenza A(H1N1) pandemic. However, as the CESAR study was criticized for methodological limitations and because results of nonrandomized case-series of ECMO are prone to selection biases, indications for VV-ECMO remain highly controversial.

SUMMARY: Before widespread diffusion of VV-ECMO for severe ARDS, new trials should test the efficacy of early initiation of the technique with tight control of mechanical ventilation in the control group, initiation of ECMO prior to transportation to ECMO centers, and the use of ECMO in every patient randomly assigned to receive it.