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Pulmonology
Calculate the P/F ratio to classify ARDS severity by Berlin criteria. Mild: 200–300 (27% mortality). Moderate: 100–200 (32%). Severe: <100 (45%). Normal P/F is 400–500.
Formula
P/F Ratio = PaO₂ (mmHg) / FiO₂ (decimal). Normal ≥ 400.
Inputs
Pulmonology
Convert nasal cannula flow rate (L/min) to FiO₂%. Each L/min adds ~4% above 21% room air baseline. Required input for P/F Ratio and A-a Gradient calculations in ICU and ED.
Formula
FiO₂ ≈ 21% + (4% × L/min)
Inputs