Value 1 Chest roentgenogram Score No alveolar consolidation Alveolar consolidation confined to 1 quadrant Alveolar consolidation confined to 2 quadrants Alveolar consolidation confined to 3 quadrants Alveolar consolidation in all 4 quadrants 0 1 2 3 4 2 Hypoxemia score PaO2/FIO2 PaO2/FIO2 PaO2/FIO2 PaO2/FIO2 PaO2/FIO2 ≥300 225-299 175-224 100-174 <100 0 1 2 3 4 3 PEEP score ( when ventilated ) PEEP PEEP PEEP PEEP PEEP ≥5 cm H2O 6-8 cm H20 9-11 cm H20    12-14 cm H2O ≥15 cm H2O 0 1 2 3 4 4 Respiratory system compliance score Compliance Compliance Compliance Compliance Compliance ≥80 ml/cm H20 60-79 ml/cm H2O 40-59 ml/cm H20 20-39 ml/cm H20 ≤19 ml/cm  H20 0 1 2 3 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.

Table 2: Components and individual values of the lung injury score.