Perinatal characteristics of the extremely premature infants studied

Preterm-born neonates who
later developed
no/mild BPD
Preterm-born neonates
who later developed
moderate/severe BPD
Subjects n1518
Male7 (47)11 (61)0.65
Gestational age at birth weeksdays262±11255±130.24
Birthweight g864±164754±1540.06
Birthweight z-scores0.11±0.54-0.29±0.670.08
Antenatal steroids13 (87)17 (94)0.93
Surfactant treatment15 (100)18 (100)1.00
Age at data acquisition h17.8±13.317.1±12.40.87
PIP cmH2O16.1±2.316.8±4.20.55
PEEP cmH2O4.9±0.484.8±0.620.74
Set tidal volume per kg mL·kg−15.4±0.785.2±0.660.34
Fraction of inspired oxygen %32±1528±100.40

Data are presented as n (%) or mean±sd, unless otherwise stated. BPD: bronchopulmonary dysplasia; PIP: ventilator peak inspiratory pressure; PEEP: ventilator positive end-expiratory pressure. #: independent samples t-test or Chi-squared test; : during data acquisition.