The goal of this interventional clinical trial is to compare patients who undergo ECMO therapy for treatment of acute respiratory distress syndrome (ARDS) and a randomized into one of two possible weaning strategy groups. Group 1: Weaning from ventilator occurs before ECMO weaning. Group 2: Weaning from ECMO occurs before weaning from ventilator. This study investigates which one of these strategies is more indulgent for the lung, and leads to less inflammation and therefore less potential side effects and an overall more favourable clinical course. As a primary criterion, measure of IL-6 in blood samples will beused. As secondary criterions, SOFA score at various time points, ventilation pressures, lung injury score (LIS), length of stay in the intensive care unit, and ventilator-associated pneumonia as well as levels of inflammatory cells and cytokines in both blood samples and bronchoalveolar lavage at different time points will be determined.