| Â | SP | PP | SP |
|---|
Gas exchanges | Time 0 | Time 1 (RM1) time 2 | Time 3 | Time 4 (RM2) time 5 | Time 6 (RM3) time 7 | Time 8 |
|---|
pH | 7.37 ± 0.08 | 7.37 ± 0.07 | 7.40 ± 0.08b | 7.36 ± 0.08c | 7.39 ± 0.08 | 7.43 ± 0.08d | 7.40 ± 0.09 | 7.47 ± 0.08e | 7.40 ± 0.08f |
PaO2, mmHg | 75.6 ± 19 | 85.4 ± 28 | 94.5 ± 39 | 88.9 ± 24 | 117 ± 63 | 138 ± 77 | 138.6 ± 70 | 171.5 ± 84g | 129.5 ± 66h |
PaCO2, mmHg | 39 ± 7 | 39 ± 7.7 | 35 ± 7.4i | 40 ± 8.4j | 37 ± 8.4 | 35 ± 7.7k | 36.4 ± 8.4 | 31.5 ± 8.4l | 36.4 ± 7.3m |
PaO2/FiO2 ratio, mmHg | 98.3 ± 28 | 111.4 ± 41.2 | 123 ± 52.3 | 115.5 ± 36 | 151.2 ± 75.7 | 178 ± 99 | 177 ± 75 | 218.2 ± 99.5n | 165.6 ± 84.5° |
- aSP: supine position; PP: prone position; RM: recruitment maneuver; PaO2: arterial oxygen partial pressure; PaCO2: arterial carbon dioxide partial pressure; PaO2/FiO2 ratio, ratio of arterial oxygen partial pressure to fraction of inspired oxygen. Gas exchanges were measured each time (from time 0 to time 8) in SP and PP (see Figure 2): inclusion, before and after each RM, before PP and at the end of the protocol (1 hour after turning to the SP). bpH time 2 versus time 1, P ≤ 0.001; cpH time 3 versus time 2, P ≤ 0.05; dpH time 5 versus time 4, P ≤ 0.001; epH time 7 versus time 6, P ≤ 0.05; fpH time 8 versus time 7, P ≤ 0.01; gPaO2 time 7 versus time 6, P ≤ 0.05; hPaO2 time 8 versus time 0, P ≤ 0.05; iPaCO2 time 2 versus time 1, P ≤ 0.05; jPaCO2 time 3 versus time 2, P ≤ 0.05; kPaCO2 time 5 versus time 4, P ≤ 0.05); lPaCO2 time 7 versus time 6, P ≤ 0.05; mPaCO2 time 8 versus time 7, P ≤ 0.01; nPaO2/FiO2 ratio time 7 versus time 6, P ≤ 0.05; °PaO2/FiO2 ratio time 8 versus time 0, P ≤ 0.05. All data are expressed as means ± standard deviations.