Three part expanded definition of clinical acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) proposed by Murray and colleagues4
| Part 1 | Acute or chronic, depending on course |
| Part 2 | Severity of physiological lung injury as determined by the lung injury score (see table 2) |
| Part 3 | Lung injury caused by or associated with known risk factor for ARDS such as sepsis, pneumonia, aspiration, or major trauma |