P/F Ratio (PaO₂/FiO₂, Berlin ARDS) — free guideline decision tool
Calculate the PaO₂/FiO₂ (P/F) ratio for ARDS severity under the Berlin definition.
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Implements the decision logic from published clinical guidelines.
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No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| PaO₂ | 80 mmHg |
|---|---|
| FiO₂ | 0.5 fraction |
→P/F ratio160mmHg
- Berlin category：Moderate ARDS
- Requires：PEEP/CPAP ≥ 5 cmH₂O for the ARDS definition.
Common questions
What is P/F Ratio (PaO₂/FiO₂, Berlin ARDS)?
Calculate the PaO₂/FiO₂ (P/F) ratio for ARDS severity under the Berlin definition.
How is P/F Ratio (PaO₂/FiO₂, Berlin ARDS) calculated? What is the core formula?
P/F = PaO₂ ÷ FiO₂ (fraction). ≤ 300 mild, ≤ 200 moderate, ≤ 100 severe ARDS, measured on PEEP ≥ 5 cmH₂O.
When is P/F Ratio (PaO₂/FiO₂, Berlin ARDS) used?
Grade hypoxaemia and classify ARDS severity.
What are the key clinical points for P/F Ratio (PaO₂/FiO₂, Berlin ARDS)?
The Berlin definition requires PEEP/CPAP ≥ 5 cmH₂O. At altitude, multiply by (barometric pressure / 760). Lower ratios indicate worse oxygenation.
What are the limits and cautions when using P/F Ratio (PaO₂/FiO₂, Berlin ARDS)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
How is P/F Ratio (PaO₂/FiO₂, Berlin ARDS) calculated in practice? Can you show a worked example?
Inputs: PaO₂ 80 mmHg, FiO₂ 0.5 fraction → Result: P/F ratio 160 mmHg（Berlin category: Moderate ARDS, Requires: PEEP/CPAP ≥ 5 cmH₂O for the ARDS definition.）
Run P/F Ratio (PaO₂/FiO₂, Berlin ARDS) now
Calculate the PaO₂/FiO₂ (P/F) ratio for ARDS severity under the Berlin definition.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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