P/F Ratio (ARDS)
PaO2/FiO2 ratio for evaluating acute respiratory distress syndrome
P/F Ratio
429mmHg
Normal (≥ 300)
Reviewed by the CareCalculus Clinical Team·MD, ICU & Emergency Medicine specialists·Updated 2026
ARDS Classification (Berlin Definition)
Mild ARDS: 200 - 300. Moderate ARDS: 100 - 200. Severe ARDS: < 100. (Assuming PEEP/CPAP ≥ 5 cmH2O)
Mathematical Metric
P/F = PaO2 / (FiO2 as decimal)
Suggested Diagnostic Protocols
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