|  | HYPO | NORMO | HYPER |
---|
 |  | NR | RM-CPAP | NR | RM-CPAP | NR | RM-CPAP |
---|
PaO2 (mmHg) | BASELINE ZEEP | 225 ± 96 | 190 ± 38 | 164 ± 40 | 228 ± 114 | 147 ± 64 | 212 ± 88 |
 | END | 466 ± 32* | 430 ± 69* | 485 ± 45* | 537 ± 40* | 231 ± 20**# | 380 ± 42†§ |
PaCO2 (mmHg) | BASELINE ZEEP | 31 ± 2 | 30 ± 7 | 34 ± 4 | 37 ± 5 | 35 ± 3 | 37 ± 7 |
 | END | 34 ± 6 | 32 ± 5 | 28 ± 9 | 37 ± 3 | 39 ± 12 | 35 ± 11 |
pHa | BASELINE ZEEP | 7.30 ± 0.10 | 7.23 ± 0.01 | 7.27 ± 0.10 | 7.25 ± 0.10 | 7.24 ± 0.10 | 7.22 ± 0.01 |
 | END | 7.11 ± 0.10 | 7.13 ± 0.01 | 7.19 ± 0.10 | 7.21 ± 0.10 | 7.23 ± 0.10 | 7.22 ± 0.01 |
Est,L (cmH2O.ml-1) | BASELINE | 3.4 ± 0.3 | 3.2 ± 0.5 | 3.0 ± 0.3 | 3.1 ± 0.3 | 3.3 ± 0.5 | 3.3 ± 0.5 |
 | END | 3.1 ± 0.4 | 1.2 ± 0.1*†| 2.6 ± 0.1 | 2.5 ± 0.4‡ | 4.1 ± 0.7#‡ | 2.8 ± 0.6†|
- Arterial oxygen partial pressure (PaO2, mmHg), arterial carbon dioxide partial pressure (PaCO2), and arterial pH (pHa) measured at BASELINE-ZEEP and after one hour of mechanical ventilation (END). Static lung elastance (Est,L) measured at BASELINE (positive end-expiratory pressure = 5 cmH2O) and at END. Animals were randomly assigned to hypovolemia (HYPO), normovolemia (NORMO) or hypervolemia (HYPER) with recruitment maneuver (RM-CPAP) or not (NR). Values are mean ± standard error of the mean of six rats in each group. *Significantly different from BASELINE (P < 0.05). †Significantly different from NR (P < 0.05). **Significantly different from HYPO-NR (P < 0.05). ‡Significantly different from HYPO-RM-CPAP (P < 0.05). #Significantly different from NORMO-NR (P < 0.05). §Significantly different from NORMO-RM-CPAP (P < 0.05).