| Patient characteristics |
| Age (years, mean ± SD) | 52.9 (± 15.7) | 50.6 (± 12.9) | 0.39 |
| Male gender (%) | 49 (73) | 38 (68) | 0.66 |
| Cancer (%) | 10 (15) | 5 (9) | 0.46 |
| Diabetes mellitus (%) | 8 (12) | 4 (7) | 0.56 |
| Congestive heart failure (%) | 10 (15) | 3 (5) | 0.15 |
| COPD (%) | 15 (22) | 7 (13) | 0.24 |
| Chronic renal failure (%) | 3 (5) | 0 (0) | 0.25 |
| Smoker (%) | 42 (63) | 26 (46) | 0.10 |
| Surgical reason for admission (%) | 12 (18) | 7 (13) | 0.56 |
| ARDS of primary pulmonary origin (%) | 60 (90) | 47 (84) | 0.51 |
| MV before ECMO (days) (median, 1st–3rd quartile) | 4 (1–8) | 1 (1–5) | < 0.01 |
| Markers of disease severity at ICU admission |
| IGS2 score (mean ± SD) | 51.3 (± 15.2) | 50.8 (± 16.5) | 0.86 |
| SOFA score (mean ± SD) | 9.7 (± 4.0) | 10.7 (± 4.1) | 0.18 |
| Septic shock (%) | 58 (87) | 46 (82) | 0.67 |
| Acute renal failure (%) | 45 (67) | 40 (71) | 0.75 |
