Table 2. Ventilation variables and parameters.
| Variables and parameters | Before the first PP session | After the first PP session | |||||
|---|---|---|---|---|---|---|---|
| Survivors (N=49) | Non-survivors (N=41) | P | Survivors (N=49) | Non-survivors (N=41) | P | ||
| VT, mL/kg PBW | 6.5 [5.8 to 6.9] | 6.2 [5.1 to 6.5] | 0.18 | 6.4 [6.0 to 7.0] | 6.5 [5.5 to 8.0] | 0.97 | |
| PEEP, cmH2O | 15 [10 to 16] | 15 [11 to 16] | 0.77 | 15 [12 to 16] | 15 [14 to 18] | 0.05 | |
| Pmax, cmH2O | 32 [26 to 39] | 35 [29 to 40] | 0.22 | 31 [29 to 36] | 36 [33 to 38] | 0.04 | |
| FiO2, % | 70 [60 to 80] | 70 [60 to 89] | 0.72 | 53 [44 to 62] | 50 [40 to 60] | 0.10 | |
| PaO2, mmHg | 66 [59 to 80] | 65 [60 to 77] | 0.64 | 92 [72 to 122] | 85 [69 to 110] | 0.29 | |
| PaCO2, mmHg | 50 [39 to 58] | 47 [42 to 62] | 0.52 | 44 [38 to 50] | 47 [35 to 56] | 0.77 | |
| HCO3–, mmol/L | 24 [21 to 27] | 22 [19 to 26] | 0.07 | 24 [21 to 28] | 22 [18 to 26] | 0.02 | |
| pH | 7.32 [7.26 to 7.39] | 7.25 [7.17 to 7.33] | 0.02 | 7.39 [7.33 to 7.42] | 7.31 [7.20 to 7.40] | 0.01 | |
| PaO2/FiO2 | 99 [79 to 130] | 101 [69 to 117] | 0.60 | 188 [117 to 226] | 166 [127 to 225] | 0.99 | |
| VD/VT | 0.27 [0.22 to 0.36] | 0.43 [0.34 to 0.51] | <0.001 | 0.25 [0.17 to 0.35] | 0.32 [0.23 to 0.52] | 0.01 | |
| ΔPRS, cmH2O | 18 [14 to 24] | 20 [15 to 24] | 0.44 | 17 [12 to 21] | 19 [16 to 24] | 0.03 | |
Variables and parameters before and after the first PP session. Data are expressed as median with IQR. VT, tidal volume; PBW, predicted body weight; PEEP, positive end-expiratory pressure; Pmax, maximum airway pressure; FiO2, fraction of inspired oxygen; PaO2, arterial oxygen tension; PaCO2, arterial carbon dioxide tension; HCO3–, arterial bicarbonate; PaO2/FiO2, ratio of arterial oxygen tension to fraction of inspired oxygen; VD/VT, dead space fraction; ΔPRS, respiratory system driving pressure.