Table 1

Numbers of patients changing disease group with increasing inspired oxygen fraction (FiO₂) across the relevant range

Low FiO₂

High FiO₂

Normal

Mild hypoxemia

Acute lung injury

Acute respiratory distress syndrome

'Effective shunt' model

n = 23

n = 15

n = 40

n = 38

Normal (n = 64)

23

14

27

0

Mild hypoxemia (n = 20)

0

1

13

6

Acute lung injury (n = 14)

0

0

0

14

Acute respiratory distress syndrome (n = 18)

0

0

0

18

Ventilation/perfusion and shunt model

n = 42

n = 19

n = 31

n = 24

Normal (n = 56)

39

12

5

0

Mild hypoxemia (n = 19)

3

6

9

1

Acute lung injury (n = 23)

0

1

16

6

Acute respiratory distress syndrome (n = 18)

0

0

1

17

Patients classified into disease groups at the lowest and highest FiO₂ level in the range, according to the following partial pressure of oxygen in arterial blood (PaO₂)/FiO₂ ratio criteria: normal (PaO₂/FiO₂ > 47 kPa) [19], mild hypoxemia (40 kPa ≤ PaO₂/FiO₂ < 47 kPa), acute lung injury (27 kPa ≤ PaO₂/FiO₂ < 40 kPa) [4,5], and acute respiratory distress syndrome (PaO₂/FiO₂ < 27 kPa) [4,5].

Karbing et al. Critical Care 2007 11:R118   doi:10.1186/cc6174