Table 1 Baseline characteristics and outcomes of cohort.

Gestational age, mean (CI), week

35.2 (34.3‒36.1)

36.1 (35.5‒36.7)

0.127

Preterm, no. (%)

20 (56)

48 (52)

0.844

Birth weight, mean (CI), kg

2.6 (2.3‒2.8)

2.6 (2.4‒2.8)

0.736

Male sex, no. (%)

23 (64)

49 (53)

0.325

1-min Apgar score, mean (CI)

8.6 (8.2‒9.0)

8.8 (8.6‒9.0)

0.225

5-min Apgar score, mean (CI)

9.5 (9.2‒9.8)

9.7 (9.6‒9.8)

0.201

Cesarean delivery, no. (%)

26 (72)

62 (67)

0.675

Inborn, no. (%)

22 (61)

66 (72)

0.290

Multiple birth, no. (%)

9 (25)

19 (21)

0.637

Antenatal steroids use, no. (%)

11 (31)

33 (38)

0.539

Premature membrane rupture, no. (%)

9 (25)

20 (22)

0.823

Maternal hypertension, no. (%)

3 (8)

6 (7)

0.710

Maternal diabetes mellitus, no. (%)

4 (11)

9 (10)

0.757

CRIB II score, mean (CI)

3.1 (2.7‒3.5)

2.9 (2.6‒3.1)

0.382

NIV type

 HFNC, no. (%)

22 (61)

79 (86)

0.003*

 NCPAP or BIPAP, no. (%)

14 (39)

13 (14)

Initial blood gas analysis

 pH, mean (CI)

7.2 (7.2‒7.2)

7.3 (7.2‒7.3)

0.004*

 PCO₂, mean (CI), mmHg

63.4 (59.5‒67.4)

57.2 (55.4‒59.1)

0.001*

 PO₂, mean (CI), mmHg

37.1 (33.7‒40.5)

40.5 (36.9‒44.2)

0.273

 Base excess, mean (CI), mmol/L

−5.3 (−6.1 to −4.6)

−4.4 (−5.0 to −3.9)

0.075

 Lactate, mean (CI), mmol/L

2.7 (2.24‒3.21)

3.4 (3.0‒3.8)

0.081

Heart rate at admission, mean (CI), bpm

143.5 (140.3‒146.6)

133.9 (133.04‒134.7)

 <0.001*

Respiratory rate at admission, mean (CI), breath/min

50.8 (46.9‒54.7)

51.7 (50.6‒52.9)

0.651

Fraction of inspired oxygen at admission, mean (CI), %

27.3 (25.8‒29.0)

22.6 (22.5‒22.8)

 < 0.001*

Pulse oximetry at admission, mean (CI), %

93.3 (91.9‒94.8)

97.2 (97.0‒97.4)

 < 0.001*

Body temperature at admission, mean (CI), °C

36.2 (36.0‒36.3)

36.1 (36.0‒36.2)

0.470

Time to intubation, mean (CI), min

124 (120)

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