Table 2

Infant characteristics according to gestational age at birth and stratified according to application of less invasive surfactant administration (LISA) versus a strategy of providing surfactant if needed after primary endotracheal intubation (n=1173)

Gestational age22–24 weeks25–27 weeks
22 weeks*23 weeks24 weeks25 weeks26 weeks27 weeks25–27 weeksP value†
LISANoYesNoYesNoYesNoYesNoYesNoYesNo
Number born (% LISA)14
(100)
3
(2)
128
(98)
10
(5)
176
(95)
43
(20)
169
(80)
89
(30)
210
(70)
90
(27)
242
(73)
222
(26)
621
(74)
Antenatal steroids, n (%)10
(71%)
3
(100%)
111/127
(87%)
10
(100%)
164
(93%)
43
(100%)
158
(93%)
86
(97%)
185
(88%)
80
(89%)
217
(90%)
209
(94%)
560
(90%)
0.07
Caesarean section, n (%)4
(29%)
1
(33%)
12
(9%)
5
(50%)
49
(28%)
20
(47%)
89
(53%)
41
(46%)
99
(47%)
43
(48%)
127
(52%)
104
(47%)
315
(51%)
0.32
Girls, n (%)4
(29%)
1
(33%)
57
(45%)
7
(70%)
78
(44%)
25
(58%)
81
(48%)
35
(39%)
87
(41%)
42
(47%)
110
(45%)
102
(46%)
278
(45%)
0.76
Birth weight, g, mean (SD)518
(60)
513
(88)
558
(68)
706
(69)
655
(89)
785
(124)
737
(148)
830
(151)
844
(179)
967
(164)
972
(200)
877
(169)
865
(204)
0.39
SGA‡, n (%)2
(14%)
1
(33%)
25
(20%)
0
(0%)
32
(18%)
4
(9%)
34
(20%)
26
(29%)
54
(26%)
22
(24%)
58
(24%)
52
(23%)
146
(24%)
0.98
Apgar 1 min, mean (SD)3.4
(2.5)
4.0
(3.0)
3.9
(2.0)
5.1
(1.9)
4.1
(2.1)
5.5
(1.8)
4.4
(2.2)
5.8
(2.0)
4.6
(2.4)
5.8
(2.0)
5.6
(2.4)
5.7
(2.0)
4.9
(2.4)
<0.001
Apgar 5 min, mean (SD)4.6
(1.9)
4.0
(1.7)
5.6
(2.1)
7.3
(1.2)
5.9
(2.1)
7.3
(1.5)
6.3
(1.9)
7.7
(1.5)
6.4
(2.2)
7.6
(1.6)
7.1
(2.1)
7.6
(1.5)
6.6
(2.1)
<0.001
Surfactant, n (%)13
(93%)
3
(100%)
118
(92%)
10
(100%)
166
(94%)
43
(100%)
149
(88%)
89
(100%)
155
(74%)
90
(100%)
137
(57%)
222
(100%)
441
(71%)
<0.001
CRIB II, mean (SD)17.1
(1.3)
16.0
(2.0)
16.0
(1.4)
14.7
(1.4)
14.5
(1.5)
12.1
(1.3)
12.9
(1.7)
10.6
(1.6)
10.7
(1.7)
8.8
(1.1)
9.1
(1.5)
10.2
(1.9)
10.7
(2.2)
0.002
ICH/PVL, n (%)§4
(29%)
1
(33%)
34
(27%)
0
(0%)
42
(24%)
4
(9%)
25
(15%)
4
(4%)
20
(10%)
9
(10%)
16
(7%)
17
(8%)
61
(10%)
0.34
Necrotising enterocolitis, n (%)0
(0%)
0
(0%)
19/127
(15%)
1
(10%)
17
(10%)
2
(5%)
13
(8%)
8
(9%)
9
(4%)
1
(1%)
6/241
(2%)
11
(5%)
28/620
(5%)
0.79
Survived to 7 days, n (%)6
(43%)
1
(33%)
95
(74%)
9
(90%)
146
(83%)
41
(95%)
151
(89%)
89
(100%)
193
(92%)
89
(99%)
222
(92%)
219
(99%)
566
(91%)
<0.001
Survived to PMA
36 weeks, n (%)
5
(36%)
1
(33%)
71
(55%)
8
(80%)
124
(70%)
40
(93%)
137
(81%)
83
(93%)
183
(87%)
86
(96%)
212
(88%)
209
(94%)
532
(86%)
<0.001
Survived to PMA
40 weeks, n (%)
5
(36%)
1
(33%)
71
(55%)
8
(80%)
123
(70%)
40
(93%)
137
(81%)
83
(93%)
181
(86%)
85
(94%)
212
(88%)
208
(94%)
530
(85%)
<0.001
MV, n (%)14
(100%)
2
(67%)
127
(99%)
9
(90%)
174
(99%)
37
(86%)
163
(96%)
52
(58%)
175
(83%)
49
(54%)
168
(69%)
138
(62%)
506
(81%)
<0.001
Days on MV, all infants, mean (SD) (Q1, Q2, Q3)20
(29) (2, 5, 33)
12
(19)
(1, 2, 18)
31
(35)
(7, 26, 43)
19
(12)
(10, 22, 26)
28
(32)
(9, 24, 37)
16
(14)
(3, 12, 28)
18
(19)
(4, 12, 28)
8
(10)
(0, 3, 12)
11
(25)
(1, 5, 14)
5
(10)
(0, 2, 6)
6
(12)
(0, 2, 6)
8
(12)
(0, 3, 12)
11
(20)
(1, 5, 14)
0.007
Days on MV, ventilated infants, mean (SD)
(Q1, Q2, Q3)
20
(29) (2, 5, 33)
18
(23)
(10, 18, 26)
31
(35)
(8, 26, 44)
21
(11)
(19, 23, 26)
29
(33)
(10, 24, 37)
18
(14)
(7, 17, 28)
19
(19)
(5, 12, 29)
13
(11)
(5, 10, 19)
14
(27)
(2, 6, 15)
10
(11)
(3, 6, 15)
9
(14)
(2, 4, 9)
13
(12)
(4, 9, 20)
14
(21)
(2, 7, 17)
0.69
Days on MV, survived to PMA 36, mean (SD) (Q1, Q2, Q3)51
(30)
(33, 33, 56)
34
(–)
(34, 34, 34)
47
(38)
(30, 38, 54)
22
(10)
(21, 24, 26)
35
(35)
(19, 29, 42)
16
(14)
(3, 13, 28)
20
(20)
(5, 15, 30)
8
(11)
(0, 3, 12)
12
(26)
(1, 5, 14)
5
(10)
(0, 1, 6)
6
(12)
(0, 2, 6)
8
(12)
(0, 3, 12)
12
(21)
(1, 5, 15)
0.005
Days on MV, survived to PMA 36 and ventilated, mean (SD) (Q1, Q2, Q3)51
(30)
(33, 33, 56)
34
(–)
(34, 34, 34)
47
(38)
(30, 38, 54)
26
(6)
(22, 25, 26)
35
(35)
(20, 29, 42)
18
(14)
(8, 17, 28)
21
(20)
(6, 16, 30)
14
(11)
(5, 11, 20)
15
(28)
(2, 7, 16)
10
(11)
(3, 6, 14)
9
(14)
(2, 5, 10)
14
(12)
(4, 9, 20)
15
(22)
(3, 8, 18)
0.41
BPD-36¶, n (%)3/5
(60%)
1/1
(100%)
62/71
(87%)
4/8
(50%)
97/124
(78%)
18/40
(45%)
81/137
(59%)
40/83
(48%)
104/183
(57%)
29/86
(34%)
83/212
(39%)
87/209
(42%)
268/532
(50%)
0.03
BPD-40¶, n (%)3/5
(60%)
1/1
(100%)
32/71
(45%)
0/8
(0%)
48/123
(39%)
4/40
(10%)
27/137
(20%)
12/83
(14%)
37/181
(20%)
9/85
(11%)
21/212
(10%)
25/208
(12%)
85/530
(16%)
0.17
Survived without BPD at PMA 36, n (%)2/14
(14%)
0/3
(0%)
7/128
(5%)
4/10
(40%)
26/176
(15%)
22/43
(51%)
55/169
(33%)
42/89
(47%)
79/210
(38%)
56/90
(62%)
128/242
(53%)
120/222
(54%)
262/621
(42%)
0.002
Survived without BPD at PMA 40, n (%)2/14
(14%)
0/3
(0%)
37/128
(29%)
8/10
(80%)
74/176
(42%)
36/43
(84%)
109/169
(64%)
70/89
(79%)
144/210
(69%)
75/90
(83%)
190/242
(79%)
181/222
(82%)
443/621
(71%)
0.003
  • Statistical analyses are limited to infants born at 25–27 weeks’ gestational age.

  • *No infants born at 22 weeks received LISA.

  • †Limited to gestational age 25–27 weeks, Welch’s t-test or χ2 test.

  • ‡Birth weight below the 10th percentile.

  • §Intracranial haemorrhage grade 3–4 and/or cystic periventricular leukomalacia.

  • ¶Only infants who survived to PMA 36/PMA 40 weeks.

  • BPD-36 and BPD-40, supplemental oxygen or positive respiratory support at 36 and 40 weeks’ PMA; ICH/PVL, intracranial haemorrhage/cystic periventricular leukomalacia; LISA, less invasive surfactant administration; MV, mechanical ventilation; n, number of infants; NEC, necrotising enterocolitis; PMA, postmenstrual age; Q1, 1st quartile; Q2, median (2nd quartile); Q3, 3rd quartile; SGA, small for gestational age.