Lung function at term reflects severity of bronchopulmonary dysplasia.
OBJECTIVE
To test whether infants with bronchopulmonary dysplasia (BPD) express the same functional impairments at term as healthy, preterm infants, and whether clinical severity of BPD is qualitatively or quantitatively related.


METHODS
Prospective measurements on a consecutive sample of 50 infants with BPD and 19 healthy preterm controls in a university hospital. BPD infants were classified as "severe," "moderate," or "mild," according to their need for oxygen. A multiple-breath nitrogen wash-out method was used to assess functional residual capacity (FRC) and gas mixing efficiency. Mechanical variables were estimated by the occlusion test.


RESULTS
Infants with severe BPD had lower FRC, less efficient gas mixing, and higher specific conductance than those with mild and moderate BPD, and the preterm controls. Mild and moderate BPD did not differ in any property from each other but differed from controls in the same variables. The elastic properties of the respiratory system appeared unaffected by BPD.


CONCLUSIONS
The ventilatory impairments in BPD were of the same nature as in healthy preterm infants when compared with term infants, but their magnitude was related to the clinical severity of the BPD. Gas mixing efficiency together with FRC appears to be useful to assess lung development in BPD.
Hjalmarson
Ola
O
Department of Pediatrics, The Sahlgrenska Academy at Göteborg, Sweden. ola.hjalmarson@pediat.gu.se
Sandberg
Kenneth L
KL
D001997:Bronchopulmonary Dysplasia / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D005652:Functional Residual Capacity / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*; D012720:Severity of Illness Index