Table 1 Characteristics of the study participants, stratified by response to surfactant. A good response to SRT was defined as either a ≥ 50% increase in the S/F ratio or an S/F ratio ≥428 at 6 h postadministration, along with no need for escalation from non-invasive ventilation to mechanical ventilation.

Sex (male)

224 (64%)

135 (60%)

88 (69%)

0.141 ^A

Gestational age (weeks)

35.8 ± 1.6

35.7 ± 1.6

35.9 ± 1.6

0.204^B

Cesarean delivery

262 (75%)

170 (77%)

92 (72%)

0.465 ^A

Multiparity

41 (12%)

22 (10%)

19 (15.0%)

0.216 ^A

Birth weight (g)

2645 (2336–3000)

2635 (2308–2995)

2670 (2360–3015)

0.504^B

Apgar 5 min

9 (8–10)

9 (7–9)

9 (8–10)

0.118^B

Antenatal corticosteroids

70 (20%)

44 (20%)

26 (20%)

0.994 ^A

pPROM

72 (21%)

40 (18%)

32 (25%)

0.145 ^A

Diabetes

54 (15%)

41 (18%)

13 (10%)

0.058 ^A

Chorioamnionitis

7 (2%)

4 (1.8)

3 (2.4%)

0.708 ^C

Fetal growth restriction

28 (8%)

18 (8.1%)

10 (7.9%)

1.000 ^A

RDS with no comorbidity

189 (54%)

123 (55%)

66 (52%)

0.577 ^A

Congenital pneumonia

118 (34%)

78 (35%)

40 (31%)

0.566 ^A

Air leaks

15 (4.3%)

7 (3.2%)

8 (6.3%)

0.263 ^A

Pneumothorax

13 (3.7%)

6 (2.8%)

7 (5%)

−

Pneumomediastinum

2 (0.6%)

1 (0.5%)

1 (0.7%)

−

Pulmonary hemorrhage

7 (2%)

2 (0.9%)

5 (3.9%)

0.104 ^C

PPHN

27 (7.7%)

14 (6.3%)

13 (10%)

0.265 ^A

TTN

16 (4.6%)

8 (3.6%)

8 (6.3%)

0.372 ^A

MAS

9 (2.6%)

6 (2.7%)

3 (2.4%)

1.000 ^C

SpO₂ (S), %

92 (88–95)

92 (88–95)

92 (89–95)

0.220^B

FiO₂ (F)

0.40 (0.35–0.50)

0.45 (0.40–0.60)

0.36 (0.31–0.45)

 < 0.001^B

S/F ratio

220 (164–263)

196 (147–237)

245 (201–287)

 < 0.001^B

Time from birth to SRT (h)

8.2 (3.5–24.9)

7.2 (3.1–22.6)

15.6 (3.8–28.3)

0.003^B

SRT dosage (mg/kg BW)

182 (150–198)

182 (150–198)

180 (151–198)

0.832^B

LISA

148 (42%)

86 (38.7%)

62 (48.8%)

0.085 ^A

INSURE

100 (28%)

67 (30.2%)

33 (26.0%)

0.477 ^A

SRT + MV

99 (28%)

69 (31.1%)

30 (23.6%)

0.173^A

SALSA

2 (0.6%)

0 (0%)

2 (1.6%)

N/A