The limitation of plateau airway pressures and the low tidal volume used in ARDS patients have been at the cost of an increased PaCO 2 . There has therefore been an increase in interest for extracorporeal CO 2 removal techniques. Different techniques have been developed but most of them have not gone to relevant, sufficiently powered clinical trials due to technical problems or insufficient CO 2 removal or oxygenation [15] . The pumpless extracorporeal lung assist (PECLA), or Novalung ® [Novalung GmbH, Heilbronn, Germany], is a compact pumpless device driven by the pressure gradient between arterial and venous blood. A femorofemoral setting is most commonly used. The main advantage of a pumpless device is a reduction in mechanical blood trauma, bleeding and hemolysis. The Novalung ® has been widely studied in ARDS. Three studies have demonstrated the clinical efficacy of this PECLA device [16] [17] [18] . CO 2 removal is efficient but oxygenation may be insufficient in these critically ill patients.