Acute respiratory failure (ARF) is one of the most frequent reasons for admission to the intensive care unit (ICU) and is associated with significant mortality. Acute respiratory failure frequently progresses to acute respiratory distress syndrome (ARDS). Here, we will focus on ARDS, the most severe form of hypoxemic ARF, and particularly on those ARDS patients requiring ventilatory support and mechanical ventilation. Among all patients admitted to ICU with ARF, almost three-quarters meet the criteria for ARDS (Bellani G, Laffey JG et al 2016). ARDS is not a disease in itself but a clinical syndrome precipitated by a large variety of clinical condi-tions, such as pneumonia, sepsis, trauma, massive pulmonary embolism, aspiration, and thus, in addition to the management of ARDS, treatment of the underlying disease is crucial.