This study focuses on patients who are at risk of developing a serious, life-threatening respiratory disease called Acute Respiratory Distress Syndrome (ARDS), which severely disrupts the function of their lungs. Preclinical studies have shown that the use of a volatile anesthetic agent such as Sevoflurane could be beneficial in the treatment and prevention of this respiratory condition. By improving gas exchange and attenuating pulmonary inflammation in particular, this agent would make it possible to prevent deterioration or to restore pulmonary function more rapidly. Half of the patients will receive inhaled sedation with sevoflurane and the other half will receive intravenous sedation already routinely used in participating ICUs (typically propofol, dexmedetomidine or a benzodiazepine, i.e. drugs approved for sedation). The aim of this study is to assess whether the use of Sevoflurane could be beneficial in the prevention of ARDS.