Table 1 Baseline (pre-randomization) characteristics comparisons

Age, years

63 ± 13

62 ± 13

63 ± 14

63 ± 13

65 ± 13

0.326

Male – n (%)

242 (65)

95 (69)

58 (59)

30 (75)

59 (65)

0.212

BMI, Kg/m² – median [IQR]

27.8 [24.2–32.1]

28.9 [25.1–34.5]

27.0 [23.5–30.2]

25.9 [23.3–31.2]

28.1 [24.9–32.0]

0.010

RASS

−1.37 ± 1.65

−1.59 ± 1.78

−1.44 ± 1.67

−1.22 ± 1.60

−1.01 ± 1.38

0.062

Postoperative – n (%)

74 (20)

17 (12)

19 (19)

7 (17)

31 (33)

0.001

Prognostic scores

Day 0 SOFA score

6.50 ± 3.35

6.60 ± 3.19

5.73 ± 3.06

5.42 ± 2.70

7.55 ± 3.80

 < 0.001^†§

Charlson Comorbidity Index

4.41 ± 3.13

4.11 ± 3.16

4.31 ± 2.87

5.24 ± 3.74

4.64 ± 3.02

0.216

APACHE III score

77 ± 30

83 ± 27

74 ± 28

71 ± 30

73 ± 35

0.023*

Mode of ventilation at enrollment

Pressure ACV – n (%)

19 (5)

10 (7)

3 (3)

0 (0)

6 (7)

0.189

Volume ACV – n (%)

22 (6)

9 (7)

8 (8)

0 (0)

5 (5)

0.327

PSV – n (%)

325 (87)

118 (85)

88 (85)

40 (98)

79 (85)

0.179

Other (including PAV +) – n (%)

10 (3)

2 (1)

4 (4)

1 (2)

3 (3)

0.665

First intubation to enrollment, days

5.9 ± 5.0

6.6 ± 4.8

6.8 ± 5.9

5.2 ± 4.6

4.5 ± 4.1

NA

Gas exchange

P_aO₂/F_iO₂

236 ± 81

218 ± 103

260 ± 101

242 ± 70

286 ± 102

 < 0.001*

P_aCO₂

41.2 ± 8.0

42.3 ± 8.1

41.1 ± 8.9

40.4 ± 6.7

39.8 ± 7.1

0.132

Respiratory parameters

F_iO₂, %

38 ± 8

43 ± 9

36 ± 6

37 ± 6

34 ± 6

 < 0.001*

Pressure support, cmH₂O

10.3 ± 3.4

11.1 ± 3.5

10.9 ± 3.2

9.7 ± 3.0

8.7 ± 2.9

 < 0.001^*†

PEEP, cmH₂O

7.8 ± 2.5

9.7 ± 2.3

7.0 ± 1.7

6.6 ± 1.4

6.1 ± 1.6

 < 0.001*^†

V_t, mL

516 ± 155

547 ± 171

461 ± 130

514 ± 128

528 ± 151

 < 0.001^†

RR, breaths/min

20.9 ± 6.8

21.7 ± 7.2

23.1 ± 7.3

21.0 ± 6.1

17.4 ± 4.4

 < 0.001*^†§

V_E, L/min

10.3 ± 3.3

11.2 ± 3.3

10.1 ± 3.2

10.4 ± 3.2

9.0 ± 3.1

 < 0.001*