TABLE 1.
Patient characteristics
| No ARDS (n=329) | ARDS (n=190) | p-value | |
| Age (years) | 62±15.4 | 63±12.9 | 0.43 |
| Male | 223 (68) | 131 (69) | 0.86 |
| BMI (kg·m−2) | 26.1 (23.0–30.0) | 27.0 (24.1–30.3) | 0.15 |
| Admission characteristics | |||
| Admission type | <0.001 | ||
| Emergency surgical | 60 (18.2) | 15 (7.9) | |
| Medical | 220 (66.9) | 161 (84.7) | |
| Planned surgical | 49 (14.9) | 14 (7.4) | |
| ARDS cause | |||
| Non-pulmonary | 48 (25.3) | ||
| Pulmonary | 142 (74.7) | ||
| ARDS severity | |||
| Mild | 26 (13.7) | ||
| Moderate | 98 (51.6) | ||
| Severe | 65 (34.2) | ||
| Pneumonia | 37 (11.2) | 126 (66.3) | <0.001 |
| APACHE II score | 21 (15–26) | 20 (15–24) | 0.012 |
| SOFA score | 9 (8–11) | 9 (7–11) | 0.033 |
| LIPS | 4.5 (3.0–6.5) | 6.0 (4.5–7.5) | <0.001 |
| Global LUS score | 5 (2–9) | 13 (8–16) | <0.001 |
| RALE score | 12 (7–18) | 20 (15–28) | <0.001 |
| COVID-19 | 2 (0.6) | 63 (33.2) | <0.001 |
| Duration of hospital stay before ICU (days) | 1.0 (1.0–3.0) | 2.0 (1.0–5.8) | <0.001 |
| Ventilation and gas exchange | |||
| MV duration at day 1 (h) | 21 (14–31) | 21 (12–29) | 0.66 |
| Compliance (mL·cmH2O−1) | 34.9 (25.5–49.4) | 28.8 (21.6–42.3) | 0.001 |
| PaO2/FIO2# (mmHg) | 233 (154–319) | 118 (86–165) | <0.001 |
| PEEP (cmH2O) | 6 (5–8) | 10 (8–12) | <0.001 |
| VT PBW (mL·kg−1) | 7.07 (6.16–8.53) | 7.24 (5.92–8.49) | 0.81 |
| VT (mL) | 464 (398–540) | 458 (384–559) | 0.86 |
| Driving pressure (cmH2O) | 13 (9–16) | 15 (10–19) | 0.001 |
| Respiratory rate (min−1) | 18 (15–22) | 20 (16–25) | <0.001 |
| Pmax (cmH2O) | 19 (15–24) | 25 (19–29) | <0.001 |
| Outcomes | |||
| Hospital LOS (days) | 17 (8–31) | 20 (12–31) | 0.023 |
| ICU LOS (days) | 6 (3–11) | 9 (4–16) | <0.001 |
| ICU mortality | 101 (30.7) | 71 (37.4) | 0.26 |
| 30-day mortality | 121 (36.8) | 78 (41.1) | 0.40 |
Data presented as mean±sd, n (%) or median (interquartile range), unless otherwise stated. ARDS: acute respiratory distress syndrome; BMI: body mass index; APACHE II: Acute Physiology and Chronic Health Evaluation II; SOFA: Sequential Organ Failure Assessment; LIPS: Lung Injury Prediction Score; LUS: lung ultrasound; RALE: Radiographic Assessment of Lung Oedema; COVID-19: coronavirus disease 2019; ICU: intensive care unit; MV: mechanical ventilation; PaO2: arterial oxygen tension; FIO2: inspiratory oxygen fraction; PEEP: positive end-expiratory pressure; VT: tidal volume; PBW: predicted body weight; Pmax: maximal pressure; LOS: length of stay. #: PaO2/FIO2 is defined as the lowest PaO2/FIO2 in the 24 h before day 1. p-values were calculated using the Chi-squared, t-test or Mann–Whitney U-test depending on the type and distribution of the variable.