RESUMEN
Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is mainly used for reversible acute respiratory failure that is difficult to correct with mechanical ventilation and other conventional measures or preparation of lung transplantation. Acute respiratory distress syndrome (ARDS) is a typical clinical syndrome of acute respiratory failure. The timing of starting VV-ECMO in severe ARDS still face many controversies and challenges. This paper we discuss the current feasible assessment methods of when to start VV-ECMO in ARDS, such as, optimization of mechanical ventilation parameters, monitoring of respiratory dynamics and hemodynamics, assessment of lung recruitability and electrical impedance tomography (EIT) real-time monitoring, etc.