Peripheral airway dysfunction in prematurity-associated obstructive lung disease identified by oscillometry

Abstract

Introduction: Mechanisms underlying lung dysfunction after preterm birth are poorly understood. Studying phenotypes of prematurity-associated lung disease may aid understanding of underlying mechanisms. Preterm-born children with and without lung dysfunction and term controls were assessed using oscillometry before and after exercise, and after postexercise bronchodilation.

Methods: Preterm-born children, born at gestation of 34 weeks or less, were classified into those with prematurity-associated obstructive lung disease (POLD; FEV₁ < LLN, FEV₁ /FVC < LLN), prematurity-associated preserved ratio of impaired spirometry (pPRISm; FEV₁ < LLN, FEV₁ /FVC ≥ LLN) and compared to preterm (FEV₁ ≥ LLN) and term controls (%predicted FEV₁ > 90%). All children underwent cardiopulmonary exercise, and oscillometry assessment at baseline, postexercise, and after postexercise bronchodilator administration.

Results: From 241 participants aged 7-12 years, complete data were available from 179: 15 children with POLD and 11 with pPRISm were compared with 93 preterm and 60 term controls. POLD group, when compared to both control groups, had impaired impedance, greater resistance, more negative (greater magnitude) reactance at low frequencies, and also had decreased compliance. pPRISm group demonstrated impaired reactance and compliance compared to term controls. No differences were noted between the preterm and term controls. Exercise had little impact on oscillometry values, but children with POLD had greatest improvements after postexercise bronchodilator administration, with decreased resistance and decreased magnitude of reactance, particularly at low frequencies.

Conclusion: Preterm-born children with obstructive airway disease had the greatest oscillometry impairments and the largest improvements after postexercise bronchodilator compared to control groups. Oscillometry can potentially be used to identify preterm-born children with lung disease to institute treatment.

Keywords: airway obstruction; albuterol; oscillometry; premature birth; respiratory mechanics.

Figure 1

Flow diagram outlining recruitment numbers for lung function testing and numbers for those included in final analysis.

Figure 2

Oscillometry spectra for impedance across frequencies for resistance and reactance (at 6–32 Hz) at baseline, postexercise and after postexercise bronchodilator, for preterm‐associated obstructive lung disease (POLD), preterm‐associated preserved ratio of impaired spirometry (pPRISm), preterm (PT_c), and term (T_c) controls.

Figure 3

Oscillometry spectra for impedance across frequencies for resistance and reactance (at 6–32 Hz) for prematurity‐associated obstructive lung disease (POLD), prematurity‐associated preserved ratio of impaired spirometry (pPRISm), preterm (PT_c), and term (T_c) controls, at baseline, postexercise, and after postexercise bronchodilator.