Table 1.

The Berlin definition of acute respiratory distress syndrome

Timing	Within 1 wk of known insult, or new or worsening symptoms
Chest imaging	Bilateral opacities not fully explained by pleural effusions, lobar collapse, or nodules
Origin of edema	Respiratory failure not fully explained by cardiac failure or fluid overload. Objective assessment is required
Oxygenation (measured on at least 5 cm H2O PEEP or CPAP)
Mild	200 mm Hg < Pao2:Fio2 ≤ 300 mm Hg
Moderate	100 mm Hg < Pao2:Fio2 ≤ 200 mm Hg
Severe	100 mm Hg ≤ Pao2:Fio2

Abbreviation: CPAP, continuous positive airway pressure.