Design of the study This is a multicenter, international, observational and non-interventional study that will collect data of all patients who are admitted to the study ICUs and who meet the inclusion/exclusion criteria between May 1st, 2016 at 00:00 hours and May 31st, 2016 at 23:59 hours. Patients who were already mechanically ventilated prior to April 1 at 00:00 hours will not be included in the study. Approval from the research ethics board of each participating institutions will be sought for this protocol. Only the investigator and research coordinators at each site should be aware of the purpose and the precise timing of the study, in order to minimize any practice modification in response to clinicians' knowledge that they are under observation.