Introduction
Materials and methods
Animals
Ventilatory setting
Pressure-controlled ventilation without spontaneous breathing
Pressure-controlled ventilation with spontaneous breathing
Lung injury
Hydrochloric acid-induced acute lung injury
Oleic acid-induced acute lung injury
Measurements
Protocol
Statistical analysis
Results
Lung injury
SB | Baseline ALI | Treatment | Lung injury | Time | Injury type | Mode | Inter-action | ||
---|---|---|---|---|---|---|---|---|---|
RR, breaths per minute | HCl | + | 28.2 ± 3.4 | 45.3 ± 8.5b |
a
|
a
|
a
| ||
- | 28.4 ± 2.8 | 28.3 ± 3.2c | |||||||
OA | + | 29.2 ± 0.1 | 43.5 ± 6.7b | ||||||
- | 29.1 ± 1.8 | 29.2 ± 1.7c | |||||||
VT, mL | HCl | + | 326 ± 46 | 212 ± 28b | |||||
- | 303 ± 23 | 272 ± 20b |
a
|
a
|
a
| TMa | |||
OA | + | 317 ± 41 | 190 ± 19b | ||||||
- | 285 ± 52 | 260 ± 31b | |||||||
VT, sb, mL | HCl | + | n/a | 135 ± 20 |
a
| ||||
- | n/a | n/a | |||||||
OA | + | n/a | 95 ± 19d | ||||||
- | n/a | n/a | |||||||
VE, liters | HCl | + | 8.8 ± 1.1 | 8.6 ± 1.5 |
a
|
a
|
a
| ||
- | 8.5 ± 0.9c | 7.6 ± 1.1c | |||||||
OA | + | 9.1 ± 1.2 | 7.7 ± 1.2 | ||||||
- | 8.0 ± 1.0c | 7.4 ± 0.6c | |||||||
PaCO2, mm Hg | HCl | + | 40 ± 6 | 45 ± 9 |
a
|
a
|
a
| TMa | |
- | 42 ± 9 | 54 ± 13c | |||||||
OA | + | 41 ± 9 | 43 ± 10 | ||||||
- | 46 ± 10 | 54 ± 17c | |||||||
Ptransp, mean, mbar | HCl | + | 5.5 ± 3.0 | 5.5 ± 4.6 |
a
|
a
|
a
| ||
- | 6.8 ± 3.3 | 8.1 ± 3.4 | |||||||
OA | + | 2.1 ± 3.0 | 2.7 ± 3.4 | ||||||
- | 0.5 ± 3.2 | 3.1 ± 3.5 | |||||||
PEEPI, dyn, mbar | HCl | + | 0.0 ± 1.1 | 0.3 ± 0.3 | |||||
- | 0.7 ± 0.6 | 0.9 ± 0.9 | |||||||
OA | + | 0.0 ± 1.6 | 0.8 ± 0.5 | ||||||
- | 0.3 ± 0.3 | 0.0 ± 1.6 | |||||||
Ccw, mL/mbar | HCl | + | 89.3 ± 39.3 | n/a |
a
| ||||
- | 96.8 ± 34.9 | 115.5 ± 64.3 | |||||||
OA | + | 40.9 ± 14.8d | n/a | ||||||
- | 39.3 ± 11.2d | 49.5 ± 27.6d | |||||||
Clung, mL/mbar | HCl | + | 19.5 ± 4.0 | n/a |
a
|
a
| |||
- | 16.4 ± 8.4 | 13.5 ± 2.8 | |||||||
OA | + | 21.3 ± 4.7d | n/a | ||||||
- | 21.7 ± 8.3d | 16.2 ± 7.9d | |||||||
R, mbar/L per second | HCl | + | 7.0 ± 0.7b | n/a |
a
|
a
| |||
- | 7.5 ± 1.6b | 8.5 ± 2.8 | |||||||
OA | + | 8.5 ± 1.0b | n/a | ||||||
- | 9.0 ± 3.0b | 11.9 ± 2.7 | |||||||
EELV, mL | HCl | + | 606 ± 171 |
a
|
a
| ||||
- | 372 ± 130c | ||||||||
OA | + | 439 ± 90d | |||||||
- | 192 ± 51c, d |
SB | BL-ALI | Treatment | Lung injury | Time | Injury type | Mode | Inter-action | ||
---|---|---|---|---|---|---|---|---|---|
PaO2/FiO2, mm Hg | HCl | + | 132 ± 18 | 150 ± 50 |
a
| TMa | |||
- | 151 ± 58 | 137 ± 104 | |||||||
OA | + | 145 ± 51 | 184 ± 116 | ||||||
- | 146 ± 68 | 109 ± 46 | |||||||
HR, beats per minute | HCl | + | 96 ± 12 | 112 ± 11 |
a
|
a
| |||
- | 100 ± 22 | 108 ± 20 | |||||||
OA | + | 102 ± 11 | 110 ± 23 | ||||||
- | 112 ± 18 | 119 ± 23 | |||||||
MAP, mm Hg | HCl | + | 79 ± 8 | 86 ± 9b |
a
|
a
| |||
- | 77 ± 23 | 92 ± 13b | |||||||
OA | + | 93 ± 12d | 97 ± 13b, d | ||||||
- | 101 ± 10d | 104 ± 15b, d | |||||||
CVP, mm Hg | HCl | + | 11 ± 2 | 10 ± 2b |
a
| ||||
- | 12 ± 3 | 12 ± 2b | |||||||
OA | + | 15 ± 2d | 14 ± 2b, d | ||||||
- | 15 ± 4d | 14 ± 3b, d | |||||||
SVR, dyne-second/cm5 | HCl | + | 1,335 ± 198 | 1,057 ± 191b |
a
|
a
|
a
| ||
- | 1,255 ± 429 | 1,072 ± 333b | |||||||
OA | + | 1,513 ± 344 | 1,281 ± 388b | ||||||
- | 1,490 ± 384 | 1,060 ± 206b | |||||||
CO, L/minute | HCl | + | 4.1 ± 0.3 | 4.6 ± 0.8 |
a
|
a
| |||
- | 4.2 ± 0.9c | 4.8 ± 0.9c | |||||||
OA | + | 4.2 ± 0.7 | 4.3 ± 0.8 | ||||||
- | 4.8 ± 0.8c | 5.5 ± 0.7c | |||||||
DO2, mL/minute | HCl | + | 323 ± 28 | 393 ± 71 |
a
|
a
| |||
- | 336 ± 63 | 369 ± 89 | |||||||
OA | + | 335 ± 89 | 360 ± 48 | ||||||
- | 408 ± 80 | 430 ± 118 | |||||||
VO2, mL/minute | HCl | + | 181 ± 31 | 172 ± 33 |
a
|
a
| |||
- | 169 ± 23 | 172 ± 32 | |||||||
OA | + | 159 ± 27c | 147 ± 34c | ||||||
- | 154 ± 32c | 167 ± 42c | |||||||
Shunt < 0.005, %QT | HCl | + | 27.1 ± 6.2 | 23.3 ± 12.7 |
a
| TMa | |||
- | 27.7 ± 7.9 | 37.4 ± 17.4b | |||||||
OA | + | 32.6 ± 18.9 | 26.0 ± 17.9 | ||||||
- | 32.4 ± 12.4 | 47.2 ± 17.1b | |||||||
Dead space > 100, %Ve | HCl | + | 33.0 ± 5.5 | 45.1 ± 11.8 |
a
| ||||
- | 34.4 ± 5.9 | 38.7 ± 3.9 | |||||||
OA | + | 39.1 ± 6.6 | 44.9 ± 12.8 | ||||||
- | 39.0 ± 6.0 | 46.2 ± 12.2 |
Pressure-controlled ventilation without spontaneous breathing
Pressure-controlled ventilation with spontaneous breathing
Discussion
Lung injury
Effects of spontaneous breathing on respiratory variables
Effects of spontaneous breathing on hemodynamic parameters
Conclusion
Key messages
-
In pigs with different types of experimental acute lung injury, spontaneous breathing during airway pressure release ventilation leads to an improvement in oxygenation by a reduction in shunt fraction.
-
Spontaneous breathing during pressure-controlled ventilation restores aeration in previously non-aerated lung regions, independently of the type of lung injury.
-
The cardiac output during pressure-controlled ventilation with suppressed spontaneous breathing is higher than with maintained spontaneous breathing, and oxygen delivery is unaffected.