Table 1. Baseline characteristics of the Beijing cohort.
| Non-ARDS (n = 103) | ARDS (n = 75) | p | |
| Female, n (%) | 34 (33.0) | 19(25.3) | 0.27 |
| Age, median (range) | 70(18–99) | 67 (18–91) | 0.32 |
| Smoking history, n (%) | 21 (20.4) | 20 (26.7) | 0.34 |
| Baseline severity of illness (1st 24 hours of ICU admission) | |||
| APACHE II, median(range)* | 15 (4–39) | 17 (6–35) | 0.79 |
| Systolic BP,<90 mmHg, n (%) | 33 (32.0) | 21 (28) | 0.64 |
| Heart rate,>100 beats/min, n (%) | 82 (79.6) | 57 (76) | 0.84 |
| Respiratory rate,>30 breaths/min, n (%) | 27 (26.7) | 31 (43.1) | 0.03 |
| Creatinine,>2.0 mg/L, n (%) | 37 (35.9) | 22 (29.3) | 0.36 |
| Bilirubin,>2.0 mg/dL, n (%) | 35 (34.0) | 21 (28) | 0.23 |
| Thrombocytopenia, ≤80×109 platelets/L, n (%) | 26 (25.2) | 28 (37.3) | 0.07 |
| Albumin,<25 g/dL, n (%) | 25 (61) | 16 (39) | 0.57 |
| Arterial pH,<7.33, n (%) | 35 (35) | 28 (37.3) | 0.74 |
| Arterial pH,<7.22, n (%) | 4 (3.9) | 7 (9.3) | 0.14 |
| Comorbidities, n (%) | |||
| Diabetes | 23 (22.3) | 16 (21.3) | 0.87 |
| Predisposing conditions for ARDS, n (%) | |||
| Sepsis syndrome | 80 (77.7) | 69 (92) | 0.01 |
| Septic shock | 47 (45.6) | 31 (41.3) | 0.57 |
| Pneumonia | 35 (34) | 29 (38.7) | 0.52 |
| Pancreatitis | 11 (10.7) | 12 (16) | 0.30 |
| Trauma | 3 (2.9) | 3 (4) | 0.70 |
| Multiple transfusions | 10 (9.7) | 5 (6.7) | 0.47 |
| Aspiration | 2 (1.9) | 10 (13.3) | 0.004 |
| >1 risk for ARDS | 38 (36.9) | 51 (68) | <0.0001 |
| Direct pulmonary injury vs. external pulmonary injury† | 36 (35) | 39 (52) | 0.02 |
| Clinical outcomes | |||
| 60-day mortality, n (%) | 38 (36.9) | 31 (41.3) | 0.55 |
| Days in ICU, median (IQR) | 8 (5–14) | 11 (7–27) | 0.21 |
| Days on mechanical ventilation, median (IQR) | 5 (2–10) | 7 (3–14) | 0.53 |
ARDS = acute respiratory distress syndrome; APACHE = Acute Physiology and Chronic Health Evaluation; ICU = intensive care unit; IQR = interquartile range.
*APACHE II score was calculated with all components within 24 hours of ICU admission.
†
Pneumonia, aspiration, pulmonary contusions, or sepsis from lower pulmonary source were categorized as direct pulmonary injury; sepsis from an extrapulmonary source, trauma without pulmonary contusions, and multiple transfusions were categorized as external pulmonary lung injury. Patients with both direct and external pulmonary injuries were considered to have direct lung injury.