Pulmonary function in infants with neonatal chronic lung disease with or without hyaline membrane disease at birth

We studied whether neonatal chronic lung disease (NCLD), hyaline membrane disease (HMD) and differences in ventilatory support affected pulmonary function during the first year of life, in 65 infants born prematurely. The relationship between body weight and oxygen consumption (V'O2) was also analysed. The study comprised 14 infants without cardiorespiratory disease, 19 infants with HMD but without NCLD, 9 infants with NCLD without prior HMD, and 23 infants with NCLD following HMD. At 6 and 12 months corrected postnatal age, static respiratory system compliance (Crs) was measured by weighted spirometry and the functional residual capacity by closed circuit helium dilution (FRCHe) combined with assessment of ventilation distribution from the mixing index (MI). Ventilatory support during the first 5 days of therapy was quantified from peak inspiratory pressure (PIP), mean airway pressure (MAP) and fractional inspiratory concentration of oxygen (FI,O2). Infants with NCLD had a shorter duration of gestation and lower birth weight than those without NCLD (Wilcoxon, p=0.002 and p=0.001, respectively). Pulmonary function at 6 and 12 months corrected age was not different between NCLD infants with or without HMD at birth. Infants with NCLD had lower Crs and MI than those without NCLD (analysis of variance (ANOVA), p