Table 1.
Baseline characteristics of the included patients.
| Overall cohort (n = 903) | VT ≤ 6 mL/kg PBW (n = 294) | VT > 6 mL/kg PBW (n = 609) | P valuea | |
|---|---|---|---|---|
| Male gender – no (%) | 659 (73.0) | 237 (80.6) | 422 (69.3) | <0.001 |
| Age, years | 65.00 [57.00–72.00] | 62.50 [55.25–70.00] | 66.00 [58.00–73.00] | <0.001 |
| Weight, kg | 86.00 [77.30–96.60] | 90.00 [80.00–99.00] | 85.00 [75.00–95.00] | <0.001 |
| Height, cm | 175.00 [170.00–183.00] | 180.00 [175.00–186.00] | 174.00 [168.00–180.00] | <0.001 |
| Predicted body weight, kg | 70.57 [63.29–77.85] | 75.12 [67.84–79.67] | 68.75 [61.47–75.12] | <0.001 |
| Body mass index, kg/m2 | 27.76 [25.29–30.85] | 27.64 [25.15–30.15] | 27.76 [25.39–31.14] | 0.176 |
| Use of non-invasive ventilation, no (%) | 77 (9.5) | 22 (8.2) | 55 (10.1) | 0.453 |
| Duration of noninvasive ventilation, hours | 7.50 [2.00–18.12] | 9.00 [3.75–20.50] | 7.00 [2.00–16.25] | 0.597 |
| Severity of ARDSb(Berlin definition) | 0.911 | |||
| Mild | 182 (20.4) | 60 (20.7) | 122 (20.3) | |
| Moderate | 612 (68.6) | 200 (69.0) | 412 (68.4) | |
| Severe | 98 (11.0) | 30 (10.3) | 68 (11.3) | |
| Severity of illness | ||||
| SOFA score | 7.00 [6.00–10.00] | 7.00 [6.00–10.00] | 7.00 [6.00–10.00] | 0.822 |
| Available, no of patients (%) | 412 (48.3) | 146 (53.9) | 266 (45.7) | 0.032 |
| Co-existing disorders, no (%) | ||||
| None | 225 (24.9) | 85 (28.9) | 140 (23.0) | 0.065 |
| Hypertension | 303 (33.6) | 92 (31.3) | 211 (34.6) | 0.355 |
| Heart failure | 37 (4.1) | 13 (4.4) | 24 (3.9) | 0.871 |
| Diabetes mellitus | 208 (23.0) | 70 (23.8) | 138 (22.7) | 0.764 |
| Chronic kidney disease | 37 (4.1) | 12 (4.1) | 25 (4.1) | 1.000 |
| Baseline creatinine, μmol/Lc | 77.00 [62.00–98.00] | 79.00 [64.00–98.00] | 76.00 [61.00–99.00] | 0.304 |
| Liver cirrhosis | 3 (0.3) | 1 (0.3) | 2 (0.3) | 1.000 |
| Chronic obstructive pulmonary disease | 70 (7.8) | 22 (7.5) | 48 (7.9) | 0.938 |
| Active haematological neoplasia | 12 (1.3) | 3 (1.0) | 9 (1.5) | 0.801 |
| Active solid neoplasia | 26 (2.9) | 9 (3.1) | 17 (2.8) | 0.988 |
| Neuromuscular disease | 4 (0.4) | 2 (0.7) | 2 (0.3) | 0.833 |
| Immunosuppression | 20 (2.2) | 9 (3.1) | 11 (1.8) | 0.337 |
| Previous medication, no (%) | ||||
| Systemic steroids | 32 (3.5) | 12 (4.1) | 20 (3.3) | 0.678 |
| Inhalation steroids | 103 (11.4) | 33 (11.2) | 70 (11.5) | 0.994 |
| Angiotensin converting enzyme inhibitor | 153 (16.9) | 50 (17.0) | 103 (16.9) | 1.000 |
| Angiotensin II receptor blocker | 103 (11.4) | 24 (8.2) | 79 (13.0) | 0.044 |
| Beta-blockers | 166 (18.4) | 51 (17.3) | 115 (18.9) | 0.641 |
| Insulin | 65 (7.2) | 23 (7.8) | 42 (6.9) | 0.713 |
| Metformin | 144 (15.9) | 58 (19.7) | 86 (14.1) | 0.039 |
| Statin | 277 (30.7) | 87 (29.6) | 190 (31.2) | 0.679 |
| Calcium channel blockers | 162 (17.9) | 47 (16.0) | 115 (18.9) | 0.332 |
Data are median [quartile 25% - quartile 75%] or No (%), unless stated otherwise. Percentages may not total 100 because of rounding.
Abbreviations, APACHE: Acute Physiology and Chronic Health Evaluation; CT: computed tomography; PBW: Predicted bodyweight; SAPS: Simplified Acute Physiology Score; SOFA: Sequential Organ Failure Assessment; VT: tidal volume.
The P value is computed comparing patients receiving VT ≤ 6 mL/kg PBW versus VT > 6 mL/kg PBW;
Severity of ARDS was classified according to the Berlin definition (Severe ARDS: P/F ratio < 100 mmHg; Moderate ARDS: P/F ratio between 100 and 200 mmHg; Mild ARDS: P/F ratio > 300 mmHg.
Most recent measurement in 24 h before intubation, or at ICU admission under invasive ventilation.