Table 1 Berlin definition of acute respiratory distress syndrome (ARDS) [2]

Imaging

Bilateral abnormalities not explained by pleural effusion, collapse or ‘nodules’

Origin of pulmonary edema

Insufficiently explained by cardiac failure or overload (if there is not a risk factor for ARDS, an echocardiogram should be performed)

Oxygenation

 Mild

200 < PaO₂/FiO₂ < 300 mmHg (26 < PaO₂/FiO₂ < 40 kPa) + PEEP ≥ 5 cm H₂O

 Moderate

100 < PaO₂/FiO₂ < 200 mmHg (13 < PaO₂/FiO₂ < 26 kPa) + PEEP ≥ 5cmH₂O

 Severe

PaO₂/FiO₂ < 100 mmHg (PaO₂/FiO₂ < 13 kPa) + PEEP ≥ 5 cm H₂O