Introduction
Materials and methods
Animals and instrumentation
Experimental protocol
Measurements
Statistical analysis
Results
Healthy animal | Lung lavage before PCV | Lung lavage before HFOV | |
---|---|---|---|
Plateau airway pressure (mbar) | 20 ± 2 | 33* ± 2 | 34* ± 3 |
Mean airway pressure (mbar) | 9 ± 1 | 13* ± 2 | 13* ± 2 |
Static lung compliance (ml/mbar) | 21 ± 1 | 11* ± 1 | 10* ± 1 |
Respiratory rate (minute-1) | 16 ± 2 | 16 ± 2 | 16 ± 2 |
tidal volume per kg bodyweight (ml/kg) | 12.8 ± 0.8 | 12.1 ± 0.2 | 12.3 ± 0.2 |
expiratory minute ventilation (l/minute) | 4.7 ± 0.7 | 5.0 ± 0.6 | 4.9 ± 0.6 |
Heart rate (minute-1) | 112 ± 12 | 127* ± 25 | 125* ± 18 |
Mean arterial pressure (mmHg) | 80 ± 11 | 81 ± 6 | 81 ± 8 |
Right atrial pressure (mmHg) | 13 ± 2 | 12 ± 3 | 12 ± 2 |
Mean pulmonary arterial pressure (mmHg) | 26 ± 6 | 39* ± 6 | 40* ± 6 |
Pulmonary artery occlusion pressure (mmHg) | 10 ± 3 | 13 ± 5 | 14 ± 3 |
Left ventricular end-diastolic pressure (mmHg) | 2 ± 1 | 3 ± 1 | 3 ± 1 |
Intracranial pressure (mmHg) | 11 ± 2 | 13 ± 2 | 13 ± 1 |
Cardiac output (l/minute) | 3.3 ± 0.3 | 3.8 ± 0.5 | 3.7 ± 0.6 |
Stroke volume (ml) | 28 ± 4 | 29 ± 8 | 30 ± 6 |
PaO2 (kPa) | 65.9 ± 8.9 | 10.8* ± 1.7 | 11.3* ± 1.9 |
PaCO2 (kPa) | 5.5 ± 0.3 | 5.5 ± 0.4 | 5.6 ± 0.3 |
Pulmonary shunt (%) | 3 ± 1 | 38* ± 4 | 39* ± 9 |
Hemodynamics and blood flows
20 mbar mean airway pressure | 25 mbar mean airway pressure | 30 mbar mean airway pressure | ||||
---|---|---|---|---|---|---|
HFOV | PCV | HFOV | PCV | HFOV | PCV | |
Transpulmonary pressure (mbar) | 15 ± 3 | 15 ± 3 | 19c ± 2 | 18a ± 3 | 22cd ± 2 | 23ab ± 2 |
Respiratory rate (minute-1) | 300 | 18 ± 10 | 300 | 21 ± 11 | 300 | 27ab ± 10 |
Oscillatory pressure amplitude (mbar) | 40 ± 7 | NA | 41 ± 8 | NA | 52cd ± 8 | NA |
Dynamic compliance of the respiratory system (ml/mbar) | NA | 18 ± 5 | NA | 17 ± 4 | NA | 12ab ± 3 |
Tidal volume per kg bodyweight (ml/kg) | NA | 13 ± 3 | NA | 12 ± 4 | NA | 10ab ± 2 |
PaO2 (kPa) | 21 ± 4 | 19 ± 6 | 57c ± 10 | 43a ± 21 | 69cd ± 7 | 71ab ± 11 |
PaCO2 (kPa) | 5.3 ± 0.3 | 5.4 ± 0.3 | 5.4 ± 0.31 | 5.3 ± 0.3 | 5.4 ± 0.3 | 5.4 ± 0.3 |
Pulmonary shunt (%) | 22 ± 8 | 23 ± 7 | 6c ± 3 | 10 ± 6 | 3cd ± 1 | 3a ± 1 |
Oxygen delivery (ml/minute) | 347 ± 64 | 356 ± 73 | 341 ± 65 | 353 ± 50 | 335 ± 63 | 338 ± 57 |
Heart rate (minute-1) | 119 ± 16 | 123 ± 19 | 121 ± 16 | 129 ± 19 | 129b ± 18 | 134a ± 18 |
Cerebral perfusion pressure (mmHg) | 74 ± 15 | 80 ± 10 | 68 ± 10 | 70 ± 8 | 62b ± 9 | 65a ± 13 |
High-frequency oscillatory ventilation | Pressure-controlled ventilation | |
---|---|---|
Cardiac output | -0.29 (0.18) | -0. 53 (0.01) |
Stroke volume | -0.23 (0.33) | -0.18 (0.41) |
Intracranial pressure | 0.48 (0.03) | 0.42 (0.06) |
Mean arterial pressure | -0.46 (0.04) | -0.52 (0.01) |
Right atrial pressure | 0.44 (0.04) | 0.19 (0.42) |
Mean pulmonary artery pressure | 0.17 (0.45) | -0.10 (0.65) |
Pulmonary artery occlusion pressure | 0.52 (<0.01) | 0.67 (<0.01) |
Left ventricular end-diastolic pressure | 0.57 (0.04) | 0.63 (0.002) |
20 mbar mean airway pressure | 25 mbar mean airway pressure | 30 mbar mean airway pressure | ||||
---|---|---|---|---|---|---|
HFOV | PCV | HFOV | HFOV | PCV | HFOV | |
Left ventricle | 220 ± 115 | 239 ± 74 | 240 ± 100 | 266 ± 64 | 191 ± 55 | 197 ± 79 |
Right ventricle | 163 ± 72 | 208 ± 80 | 206 ± 88 | 221 ± 66 | 172 ± 86 | 209 ± 80 |
Kidneys | 293 ± 89 | 265 ± 88 | 258 ± 102 | 298 ± 80 | 276 ± 102 | 240 ± 37 |
Jejunum | 47 ± 22 | 44 ± 22 | 47 ± 19 | 53 ± 17 | 48 ± 25 | 47 ± 17 |
Hemispheres | 55 ± 23 | 53 ± 20 | 46 ± 22 | 53 ± 18 | 45 ± 23 | 47 ± 10 |
Cerebellum | 43 ± 18 | 49 ± 16 | 46 ± 16 | 48 ± 22 | 46 ± 15 | 51 ± 10 |
Brainstem | 40 ± 19 | 46 ± 13 | 36 ± 14 | 43 ± 13 | 37 ± 19 | 39 ± 17 |
Transpulmonary pressure, pulmonary gas exchange, and pulmonary shunt
Discussion
Limitations
Conclusion
Key messages
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A lung recruitment maneuver by stepwise increases of the mean airway pressure to 30 mbar either by PCV with tidal volumes of 10–13 ml/kg or by HFOV had similar effects on cardiac performance and on blood flow to the nonpulmonary organs.
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The results of this study cannot be extrapolated to clinical situations without the use of inotropic drugs or vasoactive drugs.