In the study the investigators will work in periods of two hours, the situation before and after carbon dioxide removal will be compared. With this study the investigators want to prove that the CO2 in the blood decreases with at least 20 % with the use of the extracorporeal CO2 remover. More over the investigators want to prove that lower mechanical ventilation settings (thanks to CO2-removal by the ECCO2-R) will produce fewer lesions to the lungs.