Table 1 Baseline characteristics
All patients | Subphenotype 1 (non-recruitable) | Subphenotype 2 (recruitable) | p value | |
|---|---|---|---|---|
n | 99 | 62 | 37 | |
Demographics | ||||
Age (years) | 63 (10) | 65 (9) | 60 (10) | 0.008 |
Gender = Male (%) | 68 (69) | 45 (73) | 23 (62) | 0.391 |
BMI (kg m−2) | 29.18 (6.29) | 28.57 (5.37) | 30.19 (7.55) | 0.218 |
COVID symptoms duration (days) | 9 [5, 12] | 8 [5, 10] | 10 [7, 14] | 0.027 |
COVID ICU stay at inclusion (days) | 5 [1, 11] | 5 [1, 9] | 7 [0, 12] | 0.633 |
Respiratory parameters | ||||
Respiratory rate (min−1) | 25 (7) | 24 (7) | 28 (7) | 0.003 |
Tidal volume (mL) | 444 (131) | 440 (123) | 451 (144) | 0.681 |
Tidal volume / IBW (mL kg−1) | 6.47 [5.67, 7.90] | 6.36 [5.69, 7.63] | 6.76 [5.67, 7.90] | 0.395 |
Arterial pH | 7.37 [7.30, 7.43] | 7.38 [7.34, 7.44] | 7.32 [7.26, 7.42] | 0.005 |
PEEP before recruitment (cmH2O) | 10 [8, 12] | 10 [8, 11] | 10 [10, 12] | 0.008 |
Driving pressure (cmH2O) | 12 [8, 17] | 10 [7, 13] | 15 [12, 20] | < 0.001 |
Ventilatory ratio | 1.57 [1.23, 2.40] | 1.43 [1.12, 1.92] | 2.40 [1.38, 3.05] | 0.001 |
Compliance of respiratory system (cmH2O) | 33 [24, 58] | 42 [28, 73] | 29 [21, 39] | 0.004 |
Severity | ||||
Apache II score | 15 [11.5, 20.5] | 20 [12, 21.75] | 12 [10, 20] | 0.042 |
PaO2/FiO2 (mmHg) | 106 [80, 138] | 130 [98, 158] | 81 [72, 103] | < 0.001 |
ARDS category (%) | < 0.001 | |||
Mild | 6 (6.2) | 6 (10) | 0 (0) | |
Moderate | 47 (48.5) | 36 (60) | 11 (29.7) | |
Severe | 44 (45.4) | 18 (30) | 26 (70.3) | |
Outcomes | ||||
Duration of mechanical ventilation (days) | 16 [9, 27] | 15 [7.5, 25.5] | 16 [12, 27] | 0.189 |
Duration of ICU stay (days) | 18 [11, 31] | 18 [10, 30.5] | 17.5 [13, 32.5] | 0.266 |
Successfully extubated (%) | 39 (46) | 27 (53) | 12 (35) | 0.168 |
ICU mortality (%) | 43 (51) | 23 (45) | 20 (59) | 0.308 |