Table 2.
Respiratory gas exchange parameters in preterm lambs managed by invasive or non-invasive respiratory support (mean ± SD, except as noted). (Reprinted with permission, Ref 25)
| Parameter | Preterm 3d (n=5 each) | Preterm 21d (n=4 each) | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| Day of life | Invasive MV | HFNV | Week of life | Intubation and IMV | HFNV | |
| PaO2 (mmHg) | 1 | 73 ± 17 | 73 ± 11 | 1 | 76 ± 13 | 75 ± 12 |
| 2 | 85 ± 9 | 81 ± 10 | 2 | 76 ± 3 | 73 ± 14 | |
| 3 | 73 ± 8 | 77 ± 16 | 3 | 74 ± 6 | 68 ± 3 | |
|
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| FiO2 | 1 | 0.33 ± 0.03 | 0.32 ± 0.03 | 1 | 0.42 ± 0.11 | 0.30 ± 0.04 |
| 2 | 0.35 ± 0.04 | 0.31 ± 0.03 | 2 | 0.36 ± 0.04 | 0.26 ± 0.03* | |
| 3 | 0.38 ± 0.04 | 0.27 ± 0.03* | 3 | 0.33 ± 0.05 | 0.23 ± 0.02* | |
|
|
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| PaCO2 (mmHg) | 1 | 49 ± 7 | 50 ± 16 | 1 | 46 ± 7 | 52 ± 4 |
| 2 | 44 ± 5 | 55 ± 8 | 2 | 49 ± 4 | 45 ± 5 | |
| 3 | 53 ± 10 | 64 ± 11 | 3 | 47 ± 8 | 42 ± 6 | |
|
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| PIP (cmH2O)a | 1 | 22 ± 2 | 13 ± 4* | 1 | 14 ± 1 | 18 ± 3 |
| 2 | 20 ± 2 | 13 ± 4* | 2 | 15 ± 2 | 10 ± 4 | |
| 3 | 25 ± 2 | 13 ± 2* | 3 | 19 ± 5 | 4 ± 1* | |
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| ITP (cmH2O) | 1 | 22 ± 2 | 2 ± 2* | 1 | na | na |
| 2 | 20 ± 2 | 2 ± 3* | 2 | na | na | |
| 3 | 25 ± 2 | 2 ± 2* | 3 | na | na | |
|
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| Paw (cmH2O)a | 1 | 11 ± 1 | 6 ± 1* | 1 | 10 ± 1 | 9 ± 3 |
| 2 | 12 ± 2 | 6 ± 1* | 2 | 10 ± 1 | 5 ± 1* | |
| 3 | 12 ± 1 | 7 ± 1* | 3 | 10 ± 1 | 4 ± 1* | |
|
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| PEEP (cmH2O)a | 1 | 6 ± 1 | 5 ± 1 | 1 | 7 ± 2 | 7 ± 3 |
| 2 | 7 ± 1 | 6 ± 2 | 2 | 7 ± 1 | 4 ± 1* | |
| 3 | 7 ± 1 | 6 ± 3 | 3 | 7 ± 1 | 4 ± 1* | |
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| pH | 1 | 7.34 ± 0.05 | 7.35 ± 0.09 | 1 | 7.34 ± 0.10 | 7.33 ± 0.06 |
| 2 | 7.43 ± 0.07 | 7.37 ± 0.03 | 2 | 7.30 ± 0.04 | 7.43 ± 0.06* | |
| 3 | 7.37 ± 0.14 | 7.34 ± 0.08 | 3 | 7.35 ± 0.07 | 7.45 ± 0.04 | |
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| Oxygenation Index [Median (IQR)] | 1 | 5.7 (0.8) | 2.3 (0.5)† | 1 | 5.0 (2.7) | 1.9 (0.9)† |
| 2 | 4.6 (1.8) | 2.2 (0.2)† | 2 | 4.8 (0.9) | 4.0 (1.6)† | |
| 3 | 5.6 (1.7) | 2.5 (1.3)† | 3 | 3.2 (0.8) | 1.4 (0.1)† | |
|
|
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| A-a gradient (mmHg) [Median (IQR)] | 1 | 65 (14) | 47 (15) | 1 | 83 (124) | 33 (40) |
| 2 | 55 (24) | 20 (26)† | 2 | 70 ( 48) | 53 (20)† | |
| 3 | 90 (47) | 9 (11)† | 3 | 40 ( 53) | 18 (10)† | |
|
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| PaO2/FiO2 ratio [Median (IQR)] | 1 | 209 (24) | 243 (59) | 1 | 212 (102) | 261 (133) |
| 2 | 243 (58) | 284 (53) | 2 | 220 ( 49) | 233 ( 50) | |
| 3 | 184 (62) | 262 (88)† | 3 | 256 (121) | 294 ( 23) | |
*
P < 0.05 versus IMV group, unpaired t-test;
†
P < 0.05 versus IMV group by Mann-Whitney U-test
a
Pressure at the ventilator
Abbreviations: IMV, intermittent mandatory ventilation; HFNV, high-frequency nasal ventilation; PaO2, arterial partial pressure of oxygen; FiO2, fractional inspired oxygen concentration; PaCO2, arterial partial pressure of carbon dioxide; PIP, peak inspiratory pressure; ITP, intra-tracheal pressure; na, measurement not made