Calculator

PaO₂/FiO₂ ratio

New

Oxygenation ratio with ARDS severity bands (Berlin; PEEP ≥ 5 cmH₂O).

mmHg
fraction 0.21-1.0

P/F ratio

160 mmHg

Moderate ARDS range (100-200)

Severe ARDS range (≤ 100)
Moderate ARDS range (100-200)
Mild ARDS range (200-300)
Not in ARDS range

Formula

pao2 / fio2

References

  1. ARDS Definition Task Force. Acute respiratory distress syndrome: the Berlin Definition. JAMA 2012;307:2526-33.
  2. Matthay MA, et al. A new global definition of acute respiratory distress syndrome. Am J Respir Crit Care Med 2024;209:37-47.

Used in

Oxygen prescription and SpO2 targetsDefining and diagnosing ARDSLung-protective ventilation and PEEPVV vs VA ECMO: modes and indicationsECMO referral: who, when and howDaily ECMO checks and rounds

Calculators support, not replace, clinical judgement. Check inputs and units, and confirm doses with your unit protocol.