New Definition Categorizes ARDS by Hypoxemia Severity
FROM AN INTERNATIONAL CONFERENCE OF THE AMERICAN THORACIC SOCIETY
The Berlin Definition of ARDS
• Timing: Within 1 week of a known clinical insult or new or worsening respiratory symptoms.
• Chest imaging: Bilateral opacities on x-ray or CT scan not fully explained by effusions, lobar/lung collapse, or nodules.
• Origin of edema: Respiratory failure not fully explained by cardiac failure or fluid overload. Need objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factor present.
• Oxygenation:
Mild: PaO2/FIO2 of 201-300 mm Hg with positive end-expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) of 5 cm H2O or greater.
Moderate: PaO2/FIO2 of 101-200 mm Hg with PEEP of 5 cm H2O or greater.
Severe: PaO2/FIO2 of 100 mm Hg or less with PEEP of 5 cm H2O or greater.
If the altitude is higher than 1,000 m, the correction factor should be calculated as PaO2/RO2 × (barometric pressure/760).
