Abstract
Background: Prematurity disturbs alveolar growth. Previous studies in affected children reported data on lung volumes over short periods, or on airway growth. The aim of this study was to assess lung volumes and potential influencing factors in preterm children from infancy to early childhood.
Methods: Functional residual capacity (FRC) was measured in preterm children without sedation in infancy (visit 1) by multiple-breath washout (MBW), and at school age (visit 2) by MBW and plethysmography. FRC at visit 1 was derived from washin with 4% sulphur hexafluoride, maximum tracer concentration was determined by end-inspiratory molar mass. The main outcome was FRC at visit 2 from nitrogen MBW. We tested the association of absolute FRC values at visits 1 and 2 by linear regression analysis.
Results: We analysed longitudinal FRC measurements in 71 children (31 females), mean (SD) gestational age at birth and at visit 1 were 29 (3.0) and 45 (2.2) wks., mean (SD) age at visit 2 was 8.8 (1.3) yrs. We adjusted for days of postnatal oxygen supplementation, height z-score, and age at visit 2. In this multivariable model, FRC at visit 1 was associated with FRC at visit 2 (coefficient (95%CI) 3.0 (0.5 – 5.5) ml per ml increase). The model explained 57% of the variance of FRC at visit 2 (p < 0.001), with the highest proportion of variance explained by height and age at visit 2.
Conclusion: We found an association of FRC after birth with FRC at school age after adjustment for age and body size at school age, and for immaturity of the lungs at birth. To the best of our knowledge, our study is the first to show longitudinal lung volumes in preterm children in a prospective study from infancy to early childhood.
- Copyright ©ERS 2015
