Table 1.
The Berlin definition of the acute respiratory distress syndrome
| Timing | Within 1 wk of a known clinical insult or new or worsening respiratory symptoms |
| Chest imaging1 | Bilateral opacities - not fully explained by effusions, lobar/lung collage, or nodules |
| Origin of edema | Respiratory failure not fully explained by cardiac failure of fluid overload. Need objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factor present |
| Oxygenation2 | |
| Mild | 200 mmHg < PaO2/FiO2 ≤ 300 mmHg with PEEP or |
| CPAP ≥ 5 cmH2O3 | |
| Moderate | 100 mmHg < PaO2/FiO2 ≤ 200 mmHg with PEEP or |
| CPAP ≥ 5 cmH2O | |
| Severe | PaO2/FiO2 ≤ 100 mmHg with PEEP or CPAP ≥ 5 cmH2O |
1
Chest radiograph or computed tomography scan;
2
If attitude is higher than 1000 m, the correction factor should be calculated as follows: [PaO2/FiO2 × (barometric pressure/760)].
3
This may be delivered noninvasively in the mild acute respiratory distress syndrome group. CPAP: Continuous positive airway pressure; FiO2: Fraction of inspired oxygen; PaO2: Partial pressure of arterial oxygen; PEEP: Positive-end expiratory pressure.