TABLE 1.

The Berlin criteria of ARDS

Timing	Acute onset: within 1 week of known clinical insult or new/worsening respiratory symptoms.
Chest imaging	Bilateral opacities not fully explained by effusions, lobar/lung collapse or nodules seen on chest radiograph or CT.
Etiology of edema	Not fully explained by other causes such as cardiac failure or fluid overload.
PaO2/FiO2 (on PEEP ≥ 5 cm H2O)	Mild ARDS 200–300 mm Hg	Moderate ARDS 100–200 mm Hg	Severe ARDS 100 mm Hg or less

PEEP, positive end‐expiratory pressure; PaO₂; partial pressure of arterial oxygen; FiO₂, fraction of inspired oxygen; ARDS, acute respiratory distress syndrome; CT, computed tomography