Table 1 Baseline characteristics and outcome

Demographics

 Age (years), median [IQR]

0.03 [0.00–0.05]

0.21 [0.12–0.82]

55 [48–61]

74 [70–77]

NA

 Male, n (%)

10 (50)

20 (62)

14(54)

9 (53)

0.85

 Race, (Caucasian), n (%)

18 (90)

25 (86)

20 (77)

15 (88)

0.64

 Severity of illness score, median [IQR]

16 [5–22]^a

4.4 [4.0–5.0]^b

85 [66–125]^c

87 [79–106]^c

NA

Predisposing factors^d

 Direct hit, n (%)

14 (70)

27 (93)

16 (61)

12 (70)

< 0.001

 Indirect hit, n (%)

6 (30)

2 (7)

10 (39)

5 (30)

0.09

Oxygenation

 PaO₂/FiO₂ at onset, median [IQR]

88 [64–129]

137 [115–190]

124 [83–153]

146 [85–182]

0.03

 PaO₂/FiO₂ after 24 h, median [IQR]

187 [138–229]

188 [140–227]

188 [150–215]

205 [177–281]

0.41

Berlin classification

 PaO₂/FiO₂ 200-300 (mild), n (%)

2 (12)

3 (9)

3 (12)

4 (24)

0.58

 PaO₂/FiO₂ 100-200 (moderate), n (%)

4 (24)

26 (81)

14 (54)

8 (47)

0.002

 PaO₂/FiO₂ < 100 (severe), n (%)

11 (65)

3 (9)

9 (35)

5 (29)

0.001

Study procedure

 Timing BAL from time of ARDS diagnosis, days, median [IQR]

1 [0–1]

1 [0–1]

1 [0–1]

1 [0–1]

0.56

At start of ventilation

 Tidal volume (ml/kg), median [IQR]

7.0 [5.0–7.3]

6.9 [5.6–7.9]

6.6 [4.9–7.8]

5.1 [4.5–6.1]

0.07

 PEEP (cmH₂O), median [IQR]

7 [6–8]

6 [5–7]

8 [5–10]

10 [8–12]

0.002

 High-frequency oscillation, n (%)

10 (50)

0 (0)

0 (0)

0 (0)

NA

Outcome

 Mortality at ICU, n (%)

2 (10)

0(0)

11 (42)

3 (18)

< 0.001

 VFD and alive at day 28*, days, median [IQR]

21 [18–25]

18 [17–20]

17 [0–24]

21 [15–25]

0.18