Table 2A

The Berlin definition of ARDS

CriteriaDefinition
TimeWithin 1 week of a known clinical insult or new/worsening respiratory symptoms.
Chest imaging*Bilateral opacities not fully explained by effusions, lobar/lung collapse or nodules.
Origin of oedemaRespiratory failure not fully explained by cardiac failure or fluid overload; need objective assessment to exclude hydrostatic oedema if no risk factors present (eg, echocardiography).
Oxygenation†Mild
200<PaO2/FiO2≤300
PEEP or CPAP‡≥5 cm H2O
Moderate
100<PaO2/FiO2≤200
PEEP ≥5 cm H2O
Severe
PaO2/FiO2≤100
PEEP ≥5 cm H2O
  • *Chest X–ray or CT scan.

  • †If altitude higher than 1000 m correction factor should be made as follows: PaO2/FiO2x(barometric pressure/760).

  • ‡This may be delivered non-invasively in the mild ARDS.

  • ARDS, acute respiratory distress syndrome; CPAP, continuous positive airway pressure; FiO2, fractional inspired oxygen; PaO2, arterial oxygen tension; PEEP, positive end-expiratory pressure.