Diagnostic Criteria for ALI and ARDS

1. Acute Onset

2. Presence of a predisposing condition.

3. Bilateral infiltrates on frontal chest x-ray, consistent with pulmonary edema.

4. PaO2 / FiO2 < 200 mm Hg for ARDS, < 300 mm Hg for ALI, regardless of the level of positive end-expiratory pressure (PEEP).

5. Pulmonary artery occlusion pressure =18 mm Hg or no clinical evidence of left atrial hypertension.

Bernard GR, Artigas A, Brigham KL, et al. The American–European Consensus Conference on ARDS: definitions, mechanisms, relevant outcomes, and clinical trial coordination. Am Rev Respir Crit Care Med 1994;149:818–824.