The lung injury score (Murray score)
1. Chest roentgenogram score

No alveolar consolidation: 0
Alveolar consolidation confined to 1 quadrant: 1
Alveolar consolidation confined to 2 quadrant : 2
Alveolar consolidation confined to 3 quadrant : 3
Alveolar consolidation in all 4 quadrant : 4

2. Hypoxemia score

PaO2/FiO2 ≧300 :0
PaO2/FiO2 225-299 : 1
PaO2/FiO2 175-224 :2
PaO2/FiO2 100-174 :3
PaO2/FiO2 < 100 :4

3.PEEP score (when ventilated)

PEEP ≦ 5 cm H2O : 0
PEEP 6-8 cm H2O : 1
PEEP 9-11 cm H2O : 2
PEEP 12-14 cm H2O : 3
PEEP ≧ 15 cm H2O : 4

4. Respiratory system compliance score (when available)

Compliance ≧80 ml/cmH2O : 0
Compliance 60-79 ml/cmH2O : 1
Compliance 40-59 ml/cmH2O : 2
Compliance 20-39 ml/cmH2O : 3
Compliance ≦ 19 ml/cmH2O : 4

The final value is obtained by dividing the aggregate sum by the number of components that were used .
Score

No lung injury : 0
Mild-to-moderate lung injury : 0.1-2.5
Severe lung injury (ARDS) : > 2.5

* Abbreviations: PaO2/FiO2 = arterial oxygen tension to inspired oxygen concentration ratio: PEEP = positive end-expiratory pressure.