Table 3.
Respiratory variables.
| Parameter | Group | BL1 | Injury | BL2 | Time 1 | Time 2 | Time 3 | Time 4 | Time 5 | Time 6 | Group effect |
|---|---|---|---|---|---|---|---|---|---|---|---|
| MV (L·min−1) | VCV | 5.2 ± 0.9 | 5.6 ± 1.0 | 8.2 ± 1.3 | 8.1 ± 1.2 | 8.0 ± 1.1 | 7.6 ± 0.7 | 7.5 ± 0.7 | 7.5 ± 0.7 | 7.5 ± 0.7 | |
| WN | 5.8 ± 0.9 | 6.9 ± 1.5 | 9.1 ± 1.2 | 8.9 ± 1.1 | 8.9 ± 1.2 | 8.7 ± 1.2 | 8.5 ± 1.1 | 8.3 ± 1.1 | 8.2 ± 1.2 | ||
| P04 | 5.8 ± 1.2 | 6.1 ± 1.4 | 9.1 ± 1.3 | 8.9 ± 1.3 | 8.4 ± 1.5 | 8.3 ± 1.4 | 8.1 ± 1.3 | 7.9 ± 1.1 | 7.5 ± 1.0 | ||
| P10 | 5.4 ± 1.0 | 5.9 ± 1.4 | 8.6 ± 1.6 | 8.1 ± 1.2 | 8.1 ± 1.3 | 7.9 ± 1.5 | 7.9 ± 1.5 | 7.5 ± 1.6 | 7.6 ± 1.7 | ||
| VT (mL/kg) | VCV | 9.9 ± 0.2 | 10.8 ± 0.4 | 6.6 ± 0.1 | 6.6 ± 0.1 | 6.6 ± 0.2 | 6.6 ± 0.1 | 6.6 ± 0.1 | 6.6 ± 0.1 | 6.6 ± 0.1 | |
| WN | 9.9 ± 0.7 | 10.3 ± 1.2 | 6.5 ± 0.2 | 6.4 ± 0.2 | 6.4 ± 0.2 | 6.4 ± 0.2 | 6.4 ± 0.2 | 6.4 ± 0.1 | 6.4 ± 0.1 | ||
| P04 | 10.3 ± 0.6 | 10.5 ± 0.7 | 6.6 ± 0.1 | 6.5 ± 0.2 | 6.3 ± 0.4 | 6.4 ± 0.1 | 6.4 ± 0.2 | 6.5 ± 0.1 | 6.4 ± 0.1 | ||
| P10 | 10.0 ± 0.4 | 10.7 ± 0.4 | 6.6 ± 0.2 | 6.3 ± 0.4 | 6.3 ± 0.4 | 6.3 ± 0.4 | 6.4 ± 0.4 | 6.3 ± 0.6 | 6.4 ± 0.4 | ||
| RR (min−1) | VCV | 13.7 ± 2.2 | 13.6 ± 2.2 | 32.3 ± 3.4 | 32.3 ± 2.5 | 31.8 ± 2.8 | 30.5 ± 4.0 | 30.1 ± 3.9 | 30.2 ± 4.3 | 30.2 ± 4.3 | |
| WN | 13.9 ± 1.9 | 16.4 ± 5.9 | 33.1 ± 3.6 | 33.2 ± 3.5 | 33.0 ± 4.2 | 32.1 ± 4.1 | 31.5 ± 3.9 | 30.9 ± 3.7 | 30.4 ± 3.8 | ||
| P04 | 13.4 ± 2.3 | 13.6 ± 2.4 | 32.5 ± 1.9 | 32.5 ± 2.4 | 31.5 ± 3.5 | 30.4 ± 3.6 | 29.9 ± 3.5 | 29.0 ± 3.4 | 27.8 ± 3.8 | ||
| P10 | 14.3 ± 2.8 | 14.6 ± 3.3 | 33.8 ± 1.8 | 33.8 ± 1.7 | 33.5 ± 1.6 | 32.3 ± 2.4 | 32.3 ± 2.4 | 31.2 ± 2.1 | 31.9 ± 3.3 | ||
| Paw, peak (cm H2O) | VCV | 18.2 ± 1.6 | 36.9 ± 4.5 | 32.4 ± 2.3 | 32.0 ± 2.2 | 31.1 ± 2.4 | 30.8 ± 1.9 | 30.5 ± 1.9 | 30.2 ± 1.9 | 29.7 ± 2.0 | P < 0.001 |
| WN | 18.5 ± 1.6 | 37.3 ± 4.1 | 34.0 ± 3.3 | 30.2 ± 3.2 | 29.4 ± 3.4 | 29.1 ± 3.4 | 29.1 ± 3.3 | 28.7 ± 3.6 | 28.5 ± 4.0 | ** | |
| P04 | 19.3 ± 2.7 | 36.4 ± 3.7 | 33.3 ± 2.7 | 29.5 ± 3.4 | 28.9 ± 3.8 | 28.3 ± 3.8 | 28.1 ± 3.9 | 27.9 ± 4.3 | 27.6 ± 4.4 | ** | |
| P10 | 18.8 ± 1.7 | 37.7 ± 4.6 | 32.2 ± 3.1 | 28.8 ± 3.5 | 28.0 ± 3.4 | 27.3 ± 3.5 | 26.9 ± 3.5 | 26.9 ± 3.4 | 26.0 ± 3.5 | ** | |
| Paw, plat (cm H2O) | VCV | 14.9 ± 1.2 | 30.5 ± 1.9 | 29.8 ± 2.2 | 29.5 ± 2.0 | 28.8 ± 2.3 | 28.6 ± 1.9 | 28.3 ± 1.9 | 28.1 ± 2.0 | 27.7 ± 2.1 | P < 0.001 |
| WN | 15.4 ± 1.2 | 32.5 ± 2.9 | 31.4 ± 3.1 | 27.9 ± 3.3 | 27.3 ± 3.5 | 27.0 ± 3.5 | 27.0 ± 3.5 | 26.6 ± 3.7 | 26.4 ± 4.1 | ** | |
| P04 | 15.4 ± 3.3 | 30.8 ± 3.2 | 30.9 ± 2.8 | 27.3 ± 3.2 | 26.8 ± 3.6 | 26.1 ± 3.6 | 25.9 ± 3.6 | 25.7 ± 4.1 | 25.4 ± 4.3 | *** | |
| P10 | 15.1 ± 1.6 | 31.0 ± 3.4 | 29.4 ± 2.4 | 26.5 ± 3.1 | 25.7 ± 3.1 | 25.1 ± 3.1 | 24.7 ± 3.1 | 24.2 ± 3.1 | 23.8 ± 3.2 | *** | |
| Paw, mean (cm H2O) | VCV | 10.4 ± 0.5 | 17.4 ± 1.2 | 20.0 ± 0.8 | 19.9 ± 0.8 | 19.5 ± 0.9 | 19.5 ± 0.7 | 19.4 ± 0.7 | 19.3 ± 0.7 | 19.2 ± 0.7 | P < 0.001 |
| WN | 10.4 ± 0.6 | 18.5 ± 1.8 | 20.6 ± 1.2 | 18.9 ± 1.2 | 18.6 ± 1.3 | 18.5 ± 1.3 | 18.5 ± 1.3 | 18.3 ± 1.4 | 18.4 ± 1.5 | *** | |
| P04 | 10.5 ± 1.1 | 17.1 ± 1.5 | 20.1 ± 1.0 | 18.5 ± 1.1 | 18.5 ± 1.3 | 18.1 ± 1.2 | 18.1 ± 1.3 | 17.8 ± 1.5 | 17.9 ± 1.5 | *** | |
| P10 | 10.4 ± 0.8 | 17.1 ± 1.7 | 19.9 ± 1.2 | 18.4 ± 1.3 | 18.1 ± 1.2 | 17.8 ± 1.3 | 17.6 ± 1.3 | 17.8 ± 1.1 | 17.3 ± 1.2 | *** | |
| R (cm H2O/L/s) | VCV | 6.6 ± 1.0 | 11.5 ± 3.1 | 6.9 ± 1.1 | 6.7 ± 1.0 | 6.3 ± 0.9 | 6.2 ± 0.9 | 6.2 ± 0.9 | 6.1 ± 0.9 | 5.9 ± 0.9 | |
| WN | 6.5 ± 1.7 | 10.8 ± 2.9 | 7.0 ± 1.7 | 6.3 ± 1.1 | 5.8 ± 1.0 | 5.8 ± 1.0 | 5.8 ± 1.0 | 5.6 ± 1.2 | 5.6 ± 1.0 | ||
| P04 | 6.8 ± 1.1 | 10.6 ± 2.2 | 6.7 ± 1.0 | 6.2 ± 1.0 | 5.9 ± 1.2 | 5.9 ± 1.0 | 5.6 ± 1.1 | 5.6 ± 1.1 | 5.5 ± 1.1 | ||
| P10 | 7.4 ± 1.3 | 12.1 ± 2.9 | 7.4 ± 1.4 | 6.6 ± 1.4 | 6.3 ± 1.3 | 6.1 ± 1.2 | 5.9 ± 1.2 | 6.1 ± 0.9 | 5.8 ± 1.2 | ||
| E1 (cm H2O/L) | VCV | 20.5 ± 4.1 | 50.5 ± 21 | 33.0 ± 8.3 | 30.8 ± 8.2 | 28.5 ± 7.0 | 26.2 ± 6.0 | 26.0 ± 6.0 | 25.6 ± 5.5 | 24.7 ± 6.0 | |
| WN | 17.2 ± 3.1 | 45.1 ± 13 | 30.6 ± 6.7 | 30.1 ± 7.1 | 28.5 ± 8.1 | 27.3 ± 9.0 | 28.1 ± 8.7 | 26.0 ± 9.2 | 26.3 ± 8.2 | ||
| P04 | 18.9 ± 3.7 | 44.4 ± 20 | 30.4 ± 9.0 | 29.1 ± 7.8 | 29.0 ± 10.0 | 27.7 ± 9.4 | 26.9 ± 10.0 | 26.1 ± 9.9 | 26.0 ± 11.0 | ||
| P10 | 21.6 ± 5.0 | 51.9 ± 22 | 32.8 ± 8.8 | 31.6 ± 7.6 | 29.2 ± 6.6 | 27.0 ± 6.7 | 25.9 ± 6.1 | 26.7 ± 5.6 | 25.2 ± 6.3 | ||
| E2 (cm H2O/L2) | VCV | 12 ± 6.0 | 39 ± 44 | 156 ± 53 | 162 ± 52 | 160 ± 65 | 166 ± 52 | 162 ± 50 | 159 ± 49 | 154 ± 48 | P < 0.001 |
| WN | 11 ± 1.9 | 44 ± 31 | 141 ± 40 | 95 ± 27 | 93 ± 31 | 90 ± 27 | 87 ± 25 | 90 ± 28 | 85 ± 33 | *** | |
| P04 | 10 ± 12 | 24 ± 33 | 139 ± 50 | 93 ± 39 | 87 ± 43 | 82 ± 46 | 85 ± 49 | 84 ± 53 | 83 ± 54 | *** | |
| P10 | 13 ± 8.4 | 39 ± 69 | 152 ± 67 | 108 ± 31 | 97 ± 31 | 93 ± 29 | 89 ± 28 | 86 ± 27 | 77 ± 28 | *** |
Baseline 1 (BL1), Injury (IN), Baseline 2 (BL2). Minute ventilation (MV); respiratory rate (RR); mean VT per kg (VT); peak airway pressures (Paw, peak); plateau airway pressures (Paw, plat); mean airway pressure (Paw, mean); resistance of the respiratory system (R); elastance of the respiratory system (E); volume-independent elastance (E1); volume dependent elastance (E2); volume-dependence index of respiratory system elastance (%E2); conventional volume controlled ventilation (VCV); variable volume controlled ventilation with Gaussian white noise pattern in tidal volume (WN); variable volume controlled ventilation with periodicity of 4 cycles (P04) and variable volume controlled ventilation with periodicity of 10 cycles (P10). Values are shown as mean and standard deviation, and were obtained from 40 animals in total (n = 10/group). There were no missing values. Statistical significance was accepted at p < 0.05. Comparability of groups at Injury and BL2 was tested using one-way ANOVA followed by Bonferroni post-hoc tests. Differences among groups (group main effect) were tested with general linear model statistics using values at BL2 as covariate and adjusted for repeated measurements according to the Sidak procedure
p < 0.01,
p < 0.001).