Patient characteristics
| Patient characteristics | All infants n=28 | N | Survivors n=17 | N | Non-survivors n=11 | N | P value |
| Before 36 weeks PMA | |||||||
| Male sex, n (%) | 18 (64) | 28 | 11 (65) | 17 | 7 (64) | 11 | 1.00 |
| Gestational age, weeks | 26.4±1.6 | 28 | 26.4±1.4 | 17 | 26.4±1.8 | 11 | 0.40 |
| Birth weight, g | 790.0±234.2 | 28 | 820.6±267.8 | 17 | 742.7±171.2 | 11 | 0.36 |
| SGA, n (%) | 8 (29) | 28 | 5 (29) | 17 | 3 (27) | 11 | 1.00 |
| PPROM, n (%) | 5 (19) | 27 | 3 (19) | 16 | 2 (18) | 11 | 1.00 |
| Pre-eclampsia, n (%) | 9 (33) | 27 | 5 (31) | 16 | 4 (36) | 11 | 1.00 |
| Multigestation, n (%) | 2 (7) | 27 | 1 (6) | 16 | 1 (9) | 11 | 1.00 |
| Presence of NEC, n (%) | 6 (21) | 28 | 1 (6) | 17 | 5 (45) | 11 | 0.02 |
| Presence of IVH, n (%) | 9 (32) | 28 | 5 (29) | 17 | 4 (36) | 11 | 1.00 |
| Grade I | 4 (14%) | 28 | 2 (12%) | 17 | 2 (18%) | 11 | 0.71 |
| Grade II | 4 (14%) | 28 | 3 (18%) | 17 | 1 (9%) | 11 | |
| Grade III | 1 (4%) | 28 | 0 (0%) | 17 | 1 (9%) | 11 | |
| Grade IV | 0 (0%) | 28 | 0 (0%) | 17 | 0 (0%) | 11 | NA |
| Presence of ROP, n (%) | 9 (32) | 28 | 6 (35) | 17 | 3 (27) | 11 | 1.00 |
| Received dexamethasone, n (%) | 6 (21) | 28 | 3 (18) | 17 | 3 (27) | 11 | 1.00 |
| Received iNO therapy, n (%) | 3 (11) | 28 | 2 (12) | 17 | 1 (9) | 11 | 0.22 |
| At and beyond 36 weeks PMA | |||||||
| Respiratory status at 36 weeks PMA | 0.02 | ||||||
| Ventilator, n (%) | 0 (0) | 28 | 0 (0) | 17 | 0 (0) | 11 | |
| CPAP, n (%) | 8 (29) | 28 | 2 (12) | 17 | 6 (55) | 11 | |
| Supplemental O2, n (%) | 15 (54) | 28 | 10 (59) | 17 | 5 (45) | 11 | |
| BPD, n (%) | 28 (100) | 28 | 17 (100) | 17 | 11 (100) | 11 | 0.56 |
| Mild BPD, n (%) | 4 (14) | 28 | 3 (18) | 17 | 1 (9) | 11 | |
| Moderate BPD, n (%) | 1 (4) | 28 | 1 (6) | 17 | 0 (0) | 11 | |
| Severe BPD, n (%) | 23 (82) | 28 | 13 (76) | 17 | 10 (91) | 11 | |
| Age at PH confirmation beyond 36 weeks PMA, months | 2.5 (1.6–4.6) | 28 | 2.7 (1.7–5.4) | 17 | 2.1 (0.4–3.1) | 11 | 0.12 |
| Suprasystemic pressures, n (%) | 9 (32) | 28 | 3 (18) | 17 | 6 (55) | 11 | 0.095 |
| PDA, n (%) | 21 (84) | 25 | 11 (73) | 15 | 10 (91) | 11 | 0.36 |
| PAH-targeted therapy, n (%) | 14 (50) | 28 | 10 (59) | 17 | 4 (36) | 11 | 0.44 |
| Monotherapy, n (%) | 11 (39) | 28 | 9 (53) | 17 | 2 (18) | 11 | 0.12 |
| Dual therapy, n (%) | 3 (11) | 28 | 1 (6) | 17 | 2 (18) | 11 | 0.54 |
| Dexamethasone, n (%) | 7 (25) | 28 | 4 (24) | 17 | 3 (27) | 11 | 1.00 |
| iNO therapy, n (%) | 7 (25) | 28 | 4 (35) | 17 | 3 (27) | 11 | 0.22 |
| PH resolved, n (%) | 16 (57) | 28 | 16 (94%) | 17 | 0 (0%) | 11 | <0.0001 |
Comparisons between survivors and non-survivors were performed with Student’s t-test, Mann-Whitney U test and χ2 test, used accordingly. The p value shown is from the comparison between the survivors and non-survivors. Data are shown as N (%), mean±SD or median (IQR).
BPD, bronchopulmonary dysplasia; CPAP, continuous positive airway pressure; iNO, inhaled nitric oxide; IVH, any grade of interventricular haemorrhage; NA, not available; NEC, necrotising enterocolitis; PAH, pulmonary arterial hypertension; PDA, patent ductus arteriosus; PFO, patent foramen ovale; PH, pulmonary hypertension; PMA, postmenstrual age; PPROM, prolonged premature rupture of membranes (>24 hours ruptured membranes before <36 weeks gestational age); ROP, any grade of retinopathy of prematurity; SGA, small for gestational age.