How is the P/F ratio used to classify ARDS?

Berlin Definition: P/F 201–300 = mild ARDS; 101–200 = moderate ARDS; ≤100 = severe ARDS. All categories require onset within 7 days, bilateral infiltrates, and no cardiac cause.

Should the P/F ratio be corrected for PEEP?

The Berlin Definition requires a PEEP ≥5 cmH2O for diagnosis. PEEP correction using the PEEP-adjusted PaO2/FiO2 (SF ratio using SpO2 when ABG unavailable) can also be used clinically.

P/F Ratio — ARDS Severity Classification

Calculate the PaO2/FiO2 (P/F ratio) to classify ARDS severity: mild (200–300), moderate (100–200), and severe (<100 mmHg) according to the Berlin Definition, and guide ventilator management decisions.

Use the full interactive calculator below, or

P/F Ratio — ARDS Severity Classification

Frequently Asked Questions

How is the P/F ratio used to classify ARDS?

Should the P/F ratio be corrected for PEEP?