Table 2.
Body weight, diazepam dose, total volume of fluid infused, mean arterial pressure and arterial blood gas at baseline and after 2 days with various modes of mechanical ventilation, with and without applied positive end-expiratory airway pressure a
Control | CPAP | CPAP-8 | AMV | AMV-8 | CMV | CMV-8 | |
---|---|---|---|---|---|---|---|
Body weight (kg) | |||||||
Baseline | 3.4 ± 0.1 | 3.7 ± 0.3 | 3.6 ± 0.4 | 3.7 ± 0.3 | 3.4 ± 0.2 | 3.8 ± 0.4 | 3.5 ± 0.2 |
Diazepam dose (mg/kg/h) | |||||||
1.2 ± 0.0 | 1.3 ± 0.1 | 1.2 ± 0.1 | 1.3 ± 0.0 | 1.2 ± 0.1 | 1.3 ± 0.0 | ||
Total volume of fluid infused (ml/24 h) | |||||||
408 ± 14 | 499 ± 30 | 402 ± 14 | 517 ± 34b | 421 ± 20 | 545 ± 7b | ||
Mean arterial pressure (mmHg)c | |||||||
Baseline | 84.0 ± 1.4 | 88.0 ± 3.9 | 79.9 ± 4.0 | 87.2 ± 4.1 | 90.1 ± 5.8 | 86.8 ± 4.4 | 82.5 ± 1.2 |
2 days | 97.9 ± 2.3 | 91.4 ± 4.9 | 95.6 ± 4.2 | 93.4 ± 4.3 | 88.4 ± 4.1 | 83.6 ± 3.8 | |
Arterial blood gas (pH units)c | |||||||
Baselined | 7.45 ± 0.01 | 7.43 ± 0.02 | 7.46 ± 0.02 | 7.43 ± 0.02 | 7.45 ± 0.02 | 7.46 ± 0.03 | 7.47 ± 0.03 |
2 days | 7.50 ± 0.04 | 7.48 ± 0.03 | 7.46 ± 0.02 | 7.48 ± 0.01 | 7.51 ± 0.03 | 7.49 ± 0.02 | |
PaCO2 (mmHg) | |||||||
Baselined | 43.5 ± 2.0 | 44.3 ± 3.5 | 46.4 ± 1.5 | 47.6 ± 2.1 | 42.1 ± 2.8 | 47.7 ± 2.9 | 42.0 ± 3.2 |
2 days | 37.2 ± 3.3 | 40.7 ± 2.9 | 35.8 ± 3.6 | 39.4 ± 2.2 | 30.5 ± 2.9 | 42.0 ± 1.2 | |
HCO3 − (mEq/L) | |||||||
Baselined | 32.3 ± 1.8 | 28.5 ± 2.4 | 35.1 ± 1.3 | 32.3 ± 2.2 | 30.6 ± 1.8 | 33.6 ± 0.6 | 33.0 ± 2.0 |
2 days | 28.8 ± 1.7 | 29.7 ± 1.3 | 26.0 ± 3.0 | 29.6 ± 1.6 | 24.3 ± 2.0 | 32.2 ± 1.7 | |
PaO2/FIO2 (mmHg) | |||||||
Baselined | 379 ± 24 | 322 ± 10 | 375 ± 18 | 354 ± 17 | 367 ± 13 | 354 ± 21 | 371 ± 20 |
2 days | 384 ± 13 | 389 ± 13 | 389 ± 15 | 384 ± 6 | 387 ± 12 | 383 ± 12 |
aValues are mean ± SE, except mean ± SD for body weight (n = 6 animals in each group). AMV, Assist-control mechanical ventilation; CMV, Controlled mechanical ventilation (numerical value of 8 next to ventilatory mode denotes the set CPAP or PEEP of 8 cmH2O); CPAP, Continuous positive airway pressure; HCO3 −, Bicarbonate; PaCO2, Partial pressure of carbon dioxide in arterial blood; PaO2/FIO2, Ratio of partial pressure of oxygen in arterial blood to fraction of inspired oxygen; PEEP, Positive end-expiratory airway pressure. b P < 0.01 for AMV-8 and CMV-8 compared with the corresponding mode without PEEP. cData obtained at 12 hours, 24 hours and 36 hours are not shown, but they were included in statistical analysis. dBaseline arterial blood gas values were obtained during spontaneous breathing while the animals were under general anesthesia.