Methods: Patients in participating ICUs will be screened daily during a 28-day period. A registry of limited demographic data will be compiled on all screened patients. Collection of ventilation characteristics is restricted to the first three days. The first seven days or up to death, whichever comes first, will be used for collection of patient demographics (on day of admission), development of ARDS and other pulmonary complications. All patients will be followed until ICU-discharge to determine length of stay in ICU and ICU mortality. The inclusion period will be flexible for participating centers and determined at a later stage together with the study-coordinator. Data will be coded by a patient identification number of which the code will be kept safe at the local sites. The data will be transcribed by local investigators onto an internet based electronic case report form (https://www.project-redcap.org).