Table 2.
Optimum PEEP relative to titration targets
| PEEP titration targets | Healthy lungs PEEP, cmH2O |
Injured lungs PEEP, cmH2O |
p |
|---|---|---|---|
| P/F ratio, highest | 12 (12, 27) | 22 (22, 22) | 0.416 |
| Ers,, lowest | 22 (22, 22) | 22 (22, 22) | 0.317 |
| EW, lowest | 22 (17, 22) | 22 (17, 22) | 0.854 |
| EL, lowest | 22 (22, 22) | 22 (17, 22) | 0.180 |
| C.O., highest | 5 (5, 5) | 5 (5, 5) | 0.317 |
| Lung gas volume, highest | 27 (27, 27) | 27 (27, 27) | 1.000 |
| Overdistended lung, least | 5 (5, 5) | 5 (5, 5) | 1.000 |
| Normally aerated lung, most | 27 (27, 27) | 27 (27, 27) | 1.000 |
| Atelectatic lung, least | 27 (27, 27) | 27 (27, 27) | 1.000 |
| Lower inflection point | |||
| Lung gas volume | 8.9 (8.6, 9.4) | 9.5 (9.2, 10.4) | 0.138 |
| Overdistended lung | 14.9 (14.1, 14.9) | 13.3 (12.5,14.6) | 0.345 |
| Normally aerated lung | 8.3 (7.9, 8.4) | 9.2 (9.1, 9.4) | 0.043 |
| Atelectatic lung | 7.5 (6.6, 7.5) | 8.1 (7.9,8.3) | 0.345 |
| Upper inflection point | |||
| Lung gas volume | 29.0 (28.4, 29.1) | 28.6 (27.5, 29.8) | 0.500 |
| Overdistended lung | 34.8 (34.5, 36.4) | 29.7 (24, 31.8) | 0.225 |
| Normally aerated lung | 27.1 (26.0, 28.4) | 29.0 (28.2, 29.4) | 0.043 |
| Atelectatic lung | 15.1 (15.0, 15.3) | 22.3 (21.3, 22.4) | 0.043 |
Bold indicates significant p-values or lower inflection points of atelectatic and overdistended lung with the difference defining an “optimal CT inflation PEEP range”
Median (IQR) are shown
PEEP positive end-expiratory pressure; P/F ratio arterial oxygen tension/fractional inspiratory concentration of oxygen; E elastance; rs respiratory system; W chest wall; L lung; C.O. cardiac output