Aims. The aim of the study was to analyze lung growth and abnormality of infant pulmonary function tests (IPFT) in congenital diaphragmatic hernia (CDH) survivors younger than three years of age with respect to unfavorable prognostic factors. Methods. Thirty high-risk CDH survivors at the age of 1.32±0.54 years, body weight 9.76±1.25 kg were examined using IPFT: tidal breathing analysis, baby resistance/compliance, whole baby body plethysmography and rapid thoracoabdominal compression. Gore-Tex patch was used in 13% of patients (GORE group). Pulmonary hypertension was diagnosed and managed in 13% (iNO group). Standard protocols and appropriate reference values were used and obtained data were statistically analysed. Results. High incidence of peripheral airway obstruction (70%), increased value of functional residual capacity (FRC p ) 191.3±24.5 mL (126.5±36.9 % predicted; P < 0.0005), increased value of effective airway resistance (R eff ) 1.71±0.93 kPa.L -1 .s (144.4±80.1 % predicted; P < 0.01) and decreased specific compliance of the respiratory system (C rs /kg) 14.1±2.3 mL.kPa.kg -1 (i.e., 76.1±20.1 % predicted, P < 0.0005) was noted in infants with CDH in comparison with reference values. Increased value of FRC p was found in GORE group (165.7±51.9 versus 120.4±31.2, P < 0.02) and in iNO group (183.1±52.6 versus 117.8±25.7 mL; P < 0.0005). Conclusion. A high incidence of peripheral airway obstruction, an increased value of FRC p and decreased specific compliance of the respiratory system was noted in infants with CDH. Unfavorable prognostic factors (Gore-Tex patch, pulmonary hypertension) correlate with more severe alteration of pulmonary function in infants.

Background The long‐term respiratory consequences for children with bronchopulmonary dysplasia (BPD) are well known. However, there is little emphasis on monitoring preterm infants without BPD. Few studies have explored the lung function status of infants with the symptoms of chronic lung disease of prematurity (CLD). Objective To evaluate functional lung deficits in preterm infants with CLD, and to assess the perinatal determinants of diminished lung function. Methods In our cross‐sectional study, 132 preterm infants with symptomatic CLD underwent infant pulmonary function testing (iPFT) at a median post‐term age of 0.9 years. The iPFT included bodypletysmography, compliance measurement, tidal breath analysis, and rapid thoracoabdominal compression. The relationships between the respective z scores of the iPFT parameters and perinatal characteristics, postnatal treatment, and BPD status were investigated. Results Seventy‐three patients (55.3%) were born before the 28th week of gestation, and 92 (69.7%) met the BPD criteria. Functional deficits were detected in 85.8%. The obstructive ventilatory pattern was more prevalent than restrictive (36.3 vs. 12.4%, p < 0.001). Infants with restriction had lower birth weight (BW) and required a longer duration of oxygenotherapy. In a univariate model, the lung function correlated with the duration of invasive mechanical ventilation, gestational week, and BW. In a general linear model, BPD status was not an additional determinant of the iPFT results. Conclusion IPFT may reveal significant functional deficits in preterm infants with CLD even without BPD. The current symptoms and perinatal factors may be more important determinants of functional deficits than the BPD status itself.