Table 1.
Comparison of patients with acute respiratory distress syndrome with or without diffuse alveolar damage patterns at histological examination
| ARDS without DAD (n = 197) | ARDS with DAD (n = 159) | p Value | |
|---|---|---|---|
| Characteristics of the patients | |||
| Age, years | 66.4 ± 14.0 | 64.3 ± 14.7 | 0.17 |
| Female sex, n (%) | 58 (29.4%) | 68 (42.8%) | 0.01 |
| SAPS II, points | 55.5 ± 19.6 | 50.9 ± 16.1 | 0.02 |
| Duration of MV before death, days | 12.7 ± 21.7 | 13.1 ± 11.0 | 0.82 |
| Duration of ARDS evolution ≥ 72 h, n (%) | 101 (51%) | 128 (81%) | <0.01 |
| Risk factor triggering ARDS | |||
| Pneumonia, n (%) | 62 (31.5%) | 66 (41.5%) | 0.04 |
| Other pulmonary risk factors of ARDS, n (%) | 12 (6.1%) | 7 (4.4%) | 0.48 |
| Shock, n (%) | 118 (59.9%) | 83 (52.2%) | 0.14 |
| Extrapulmonary sepsis, n (%) | 73 (37.1%) | 56 (35.2%) | 0.72 |
| Pancreatitis, n (%) | 12 (6.1%) | 7 (4.4%) | 0.48 |
| Blood gases | |||
| PaO2, mmHg | 93 ± 37 | 79 ± 27 | <0.01 |
| PaO2/FiO2, mmHg | 140 ± 67 | 104 ± 53 | <0.01 |
| PaCO2, mmHg | 44.5 ± 12.8 | 49.1 ± 15.0 | <0.01 |
| Severity of hypoxemia | <0.01 | ||
| 200 < PaO2/FiO2 ≤ 300 mmHg, n (%) | 43 (22%) | 6 (4%) | |
| 100 < PaO2/FiO2 ≤ 200 mmHg, n (%) | 85 (43%) | 56 (35%) | |
| PaO2/FiO2 ≤ 100 mmHg, n (%) | 69 (35%) | 97 (61%) | |
| Ventilatory settings | |||
| Tidal volume, ml | 620 ± 133 | 623 ± 157 | 0.87 |
| Respiratory rate, cycles/minute | 20 ± 6 | 22 ± 7 | <0.01 |
| Minute ventilation, L/minute | 11.9 ± 3.2 | 13.1 ± 3.4 | <0.01 |
| FiO2 | 0.75 ± 0.25 | 0.85 ± 0.22 | <0.01 |
| PEEP, cmH2O | 7.9 ± 4.5 | 9.6 ± 4.1 | <0.01 |
| PEEP ≥ 10 cmH2O, n (%) | 91 (46%) | 106 (67%) | <0.01 |
| Physiological parameters | |||
| Peak pressure, cmH2O | 37 ± 10 | 44 ± 10 | <0.01 |
| Dynamic driving pressure (peak − PEEP), cmH2O | 28 ± 11 | 34 ± 9 | <0.01 |
| Dynamic compliance, ml/cmH2O | 24 ± 11 | 20 ± 7 | <0.01 |
| Dynamic compliance < 40 ml/cmH2O, n (%) | 174 (88%) | 155 (97%) | <0.01 |
| VE corrected PaCO2, L/minute | 13 ± 5 | 16 ± 7 | <0.01 |
| VE corrected PaCO2 ≥ 10 L/minute, n (%) | 135 (69%) | 133 (84%) | <0.01 |
| Extent of infiltrates on chest radiograph | <0.01 | ||
| Two quadrants, n (%) | 64 (32%) | 17 (11%) | |
| Three quadrants, n (%) | 63 (32%) | 41 (26%) | |
| Four quadrants, n (%) | 70 (36%) | 101 (63%) | |
| Lung weight at autopsy examination, g | 1567 ± 709 | 1848 ± 748 | <0.01 |
Abbreviations: ARDS Acute respiratory distress syndrome, DAD Diffuse alveolar damage, MV Mechanical ventilation, SAPS Simplified Acute Physiology Score II, PEEP Positive end-expiratory pressure, VE Minute ventilation, PaCO 2 Partial pressure of arterial carbon dioxide, PaO 2, Partial pressure of arterial oxygen, PaO 2 /FiO 2 Ratio of partial pressure of arterial oxygen to fraction of inspired oxygen