Perinatal characteristics and at gestational corrected age (GCA) of 1 year

Non-BPD group (n=28)BPD group (n=36)Missing (BPD/non-BPD)p-value
Male18/28 (64%)24/36 (67%)00.84
Weeks of pregnancy31.0±2.628.2±2.30<0.0001
Birth weight g1484±4401059±3340<0.0001
Birth weight percentiles52.5±29.651.6±31.300.91
Surfactant therapy11/28 (39%)21/36 (58%)00.13
Prenatal dexamethasone#7/28 (25%)16/36 (44%)00.11
Postnatal dexamethasone0/28 (0%)20/36 (56%)0<0.0001
HMD14/28 (50%)27/36 (75%)00.036
FIO2 at 36 weeks0.210.29±0.086/0<0.0001
GCA at lung function testing months9.7±3.810.4±3.01/10.47
CHL at lung function testing cm71±971±72/10.73
FRC z-score for CHL0.05±1.03)0.37±1.312/10.30
Compliance z-score for CHL0.32±1.03−0.56±0.823/10.0005
Mixing efficiency %56±1043±172/20.0012

Data are presented as mean±sd or n/N (%), unless otherwise stated. Mean weeks of pregnancy and mean birth weight were significantly different between groups. GCA in months for some patients was less than 12 months because they could not be tested at GCA 12 months. Mean PIPmax: mean maximum positive inspiratory pressure during mechanical ventilation in cmH2O; mean FIO2 at 36 weeks: fractional inspired oxygen concentration in ambient air at post-conceptional age of 36 weeks; GCA: gestational corrected age; BPD: bronchopulmonary dysplasia; CHL: crown–heel length; HMD: hyaline membrane disease; PIPmax: maximum positive inspiratory pressure; FIO2: inspiratory oxygen fraction. #: Prenatal dexamethasone was administered ante partum to mothers if admitted on time before delivery to the hospital.