Objectives: To assess longitudinally small airway function in children born extremely prematurely and whether there was a correlation between airway function in infancy and at 11-14 years.
Working hypotheses: There would be tracking of airways obstruction and small airway function would deteriorate during childhood in those born extremely prematurely.
Study design: A longitudinal study.
Patient-subject selection: Thirty-five children with a mean gestational age of 26 weeks had lung function assessed at 1 year corrected and 11-14 years of age.
Methodology: Lung volumes were measured by helium gas dilution (FRCHe ) and plethysmography (FRCpleth ) and small airway function assessed by calculating the FRCHe :FRCpleth ratio. Airway function was assessed at 1 year corrected by measurement of airway resistance (Raw ) and at 11-14 years by assessment of Raw , forced expiratory flow from 75% of vital capacity (FEF75 ), and forced expiratory volume at one second (FEV1 ).
Results: At the first assessment, the children had a mean (SD) FRCHe :FRCpleth of 0.90 (0.13) and at the second, 0.83 (0.12) (P = 0.035). There was a significant 0.54% decrease (95%CI: -1.02%, -0.06%) in FRCHe :FRCpleth for increased age per year after adjusting for birth weight, gestational age, sex, and bronchopulmonary dysplasia (P = 0.027). There were significant correlations between Raw at the first assessment and Raw (P = 0.012), FEF75 (P = 0.034), and FEV1 (P = 0.04) at 11-14 years.
Conclusions: These results demonstrate in those born extremely prematurely there is tracking of airway function during childhood.
Keywords: airway function; extreme prematurity; lung volume; small airway function.
© 2018 Wiley Periodicals, Inc.