Table 2 Berlin definition of acute respiratory distress syndrome

Timing

Within 1 week of a known clinical insult or new or worsening respiratory symptoms

Chest imaging^a

Bilateral opacities—not fully explained by effusions, lobar/lung collapse, or nodules

Origin of edema

Respiratory failure not fully explained by cardiac failure or fluid overload.

Need objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factors present

Oxygenation^b

 Mild

200 mmHg < PaO₂/FIO₂ ≤ 300 mmHg with PEEP or CPAP ≥ 5 cmH₂O^c

 Moderate

100 mmHg < PaO₂/FIO₂ ≤ 200 mmHg with PEEP ≥ 5 cmH₂O

 Severe

PaO₂/FIO₂ ≤ 100 mmHg with PEEP ≥ 5 cmH₂O