Acute respiratory distress syndrome (ARDS) is characterized by permeability pulmonary edema and refractory
hypoxemia. Recently, the new definition of ARDS has been published, and this definition suggested severity-oriented
respiratory treatment by introducing three levels of severity according to PaO2/FiO2 and positive end-expiratory
pressure. Lung-protective ventilation is still the key of better outcome in ARDS. Through randomized trials, short-term
use of neuromuscular blockade at initial stage of mechanical ventilation, prone ventilation in severe ARDS, and
extracorporeal membrane oxygenation in ARDS with influenza pneumonia showed beneficial efficacy. However, ARDS
mortality still remains high. Therefore, early recognition of ARDS modified risk factors and the avoidance of aggravating
factors during the patient's hospital stay can help decrease its development. In addition, efficient antifibrotic strategies
in late-stage ARDS should be developed to improve the outcome.