 This observational prospective clinical study will describe and compare sRAGE levels in the alveolar edema fluid and in the plasma from ICU patients enrolled within the first 24 hours after onset of ALIARDS andor severe sepsisseptic shock, and from patients under mechanical ventilation control group. Edema fluid and plasma samples will be collected simultaneously on day 1, day 3, day 6, and day 28 or at ICU discharge, in order to describe kinetics of evolution of sRAGE levels. Undiluted pulmonary edema fluid samples will be collected in intubated patients only, and blood samples will be gathered from an indwelling arterial catheter. The concentrations of sRAGE will be measured in duplicate by ELISA. 