Acute Onset — Within 1 Week of Known Clinical Insult

No — onset not acute or > 1 week from insult+0Yes — onset within 1 week of known insult+1

Bilateral Opacities on CXR or CT Chest

No bilateral opacities (or explained by effusion/collapse/nodules)+0Yes — bilateral opacities not fully explained by other causes+1

Respiratory Failure Not Fully Explained by Cardiac Failure or Fluid Overload

No — edema fully explained by cardiac failure or fluid overload+0Yes — cannot be fully attributed to cardiac failure or fluid overload+1

PaO₂/FiO₂ Ratio (with PEEP or CPAP ≥ 5 cmH₂O)

P/F > 300 mmHg — does not meet ARDS oxygenation criterion (or PEEP < 5 cmH₂O)+0P/F 201–300 mmHg — Mild ARDS (with PEEP ≥ 5 cmH₂O)+1P/F 101–200 mmHg — Moderate ARDS (with PEEP ≥ 5 cmH₂O)+2P/F ≤ 100 mmHg — Severe ARDS (with PEEP ≥ 5 cmH₂O)+3

Berlin Definition — ARDS Diagnosis and Severity

Berlin Definition — ARDS Diagnosis and Severity