TABLE 1

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	p-value^#
Subjects n	15	18
Male	7 (47)	11 (61)	0.65
Gestational age at birth weeks^days	26²±1¹	25⁵±1³	0.24
Birthweight g	864±164	754±154	0.06
Birthweight z-scores	0.11±0.54	-0.29±0.67	0.08
Antenatal steroids	13 (87)	17 (94)	0.93
Surfactant treatment	15 (100)	18 (100)	1.00
Age at data acquisition h	17.8±13.3	17.1±12.4	0.87
PIP^¶ cmH₂O	16.1±2.3	16.8±4.2	0.55
PEEP^¶ cmH₂O	4.9±0.48	4.8±0.62	0.74
Set tidal volume per kg^¶ mL·kg⁻¹	5.4±0.78	5.2±0.66	0.34
Fraction of inspired oxygen^¶ %	32±15	28±10	0.40

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.