Respiratory outcome in school-aged, very-low-birth-weight children in the surfactant era

Aim. To assess respiratory outcome and its predictors during the surfactant era in very-low-birthweight (VLBW, birth weight < 1500 g) schoolchildren with and without bronchopulmonary dysplasia (BPD). Methods. At 7 - 8 years of age, 34 VLBW children with BPD diagnosed at a postnatal age of 28 d underwent flow-volume spirometry, metacholine challenge, bronchodilatation test, whole body plethysmography and diffusion capacity measurement. Fourteen of them had not recovered from BPD by a corrected gestational age of 36 wk (sBPD subgroup). The age- and sex-matched control groups comprised 34 VLBW cases without BPD and 34 term children. Results. Current respiratory symptoms in contact with cold air and/ or upon exercise were reported in one-third of the VLBW children. Only half of the symptomatic VLBW cases without BPD had inhaled medications. Compared with term controls, the BPD cases had lower forced expiratory volume in 1 s (FEV1), higher ratio of residual volume to total lung capacity and higher airway resistance. Lower FEV1 and specific conductance were found in the sBPD subgroup compared to both control groups. Additionally, their vital capacity was lower than in term controls. A higher rate of bronchial hyper-reactivity and lower diffusion capacity of the lungs were detected in VLBW as against term cases. Low birth weight, long duration of oxygen therapy, low socio-economic status and exposure to animal dander emerged as predictors of poorer respiratory outcome. Conclusion. In the surfactant era, birth weight, neonatal respiratory morbidity, as well as later environmental factors appear to affect the respiratory outcome of VLBW children. However, careful pulmonary follow-up of all VLBW children seems to be indicated regardless of the severity of neonatal respiratory problems.