PaO₂/FiO₂ Ratio calculator
Result
250
Moderate ARDS (100–200)
Berlin ARDS: mild 200–300, moderate 100–200, severe <100. Measured at PEEP ≥5 cmH₂O.
How to use it
- 1
ABG for PaO₂. Arterial sample, PaO₂ in mmHg.
- 2
Record FiO₂ at time of ABG. E.g., 40% O₂ via Venturi = FiO₂ 0.40.
- 3
Classify ARDS severity. Guides PEEP titration, prone positioning (<150), ECMO referral (<80).
When to use it
- ARDS classification
- Berlin criteria: bilateral infiltrates + PF <300 on PEEP ≥5 + not explained by CHF.
- Ventilator management
- PF ratio drives daily ventilation decisions in ICU.
- Prone threshold
- PF <150 despite FiO₂ ≥0.6: prone position ≥16h/day (PROSEVA).
A reference for clinicians and students, not medical advice. A score supports a decision; it does not make one. Check every result against the patient in front of you and your local protocol.
At a glance
- Specialty
- Pulmonology
- Inputs
- 2
- Type
- Formula
