Table 1.
Respiratory parameters
| Baseline | Injury | PSV | BIPAP+SB mean | BIPAP+SB controlled | BIPAP+SB spont | |
|---|---|---|---|---|---|---|
| MV (L/min) | 5.1 ± 1.7 | 4.1 ± 1.7 | 6.6 ± 1.9 | 6.2 ± 2.1 | 2.3 ± 0.9 †,‡ | 4.0 ± 2.2 †,‡,§ |
| VT (mL) | 347 ± 58 | 349 ± 61 | 202 ± 48 | 129 ± 40 † | 255 ± 103 | 97 ± 34 †,‡,§ |
| RR (/min) | 15 ± 4 | 14 ± 4 | 34 ± 11 | 51 ± 17 † | 9 ± 3 †,‡ | 43 ± 17 †,‡,§ |
| Ti/Ttot | 0.49 ± 0.01 | 0.49 ± 0.01 | 0.33 ± 0.05 | -- | 0.24 ± 0.08 † | 0.26 ± 0.06 †,‡ |
| Ppeak (cmH2O) | 20 ± 2 | 34 ± 3 * | 23 ± 2 | -- | 24 ± 3 | -- |
| Paw mean (cmH2O) | 11 ± 1 | 15 ± 1 * | 9 ± 1 | 9 ± 1 | 14 ± 2 †,‡ | 5 ± 1 †,‡,§ |
| Ppl mean (cmH2O) | 3 ± 2 | 7 ± 2 * | 2 ± 1 | 2 ± 1 | 6 ± 3 †,‡ | 1 ± 1 †,‡,§ |
| PEEPi,dyn (cmH2O) | -- | -- | 1 ± 1 | 1 ± 1 | -- | -- |
| PTP (cmH2O.s.min-1) | -- | -- | 7 ± 5 | 91 ± 54 † | -- | -- |
| P0.1 (cmH2O) | -- | -- | 1 ± 1 | 3 ± 1 † | -- | -- |
Values are given as mean ± standard deviation; baseline, before induction of acute lung injury; injury, after induction of acute lung injury. The contributions of spontaneous and controlled breaths to BIPAP+SBmean were weighted by their respective rates (weighted mean). * P < 0.05 vs. Baseline; † P < 0.05 vs. PSV; ‡ P < 0.05 vs. BIPAP+SBmean; § P < 0.05 vs. BIPAP+SBcontolled.
BIPAP+SBcontrolled, controlled breath cycles during BIPAP+SBmean; BIPAP+SBmean, biphasic positive airway pressure + spontaneous breathing; BIPAP+SBspont, spontaneous breath cycles during BIPAP+SBspont; MV, minute volume; P0.1, airway pressure generated 100 ms after onset of an occluded inspiratory effort; Paw mean, mean airway pressure; PEEPi,dyn, dynamic intrinsic end-expiratory pressure; Ppeak, peak airway pressure; Ppl mean, mean transpulmonary pressure; PSV, pressure support ventilation; PTP, inspiratory esophageal pressure time product; RR, respiratory rate; Ti/Ttot, inspiratory to total respiratory time; VT, tidal volume.