Tidal Breathing Analysis as a Prognostic Index for Airway Obstruction Trajectory and Asthma in Preterm Infants.

Introduction: An easy-to-implement and accurate lung function assessment tool for preterm infants is crucial to manage lifelong respiratory morbidities. We aimed to determine which pulmonary function parameters in preterm infants can predict the trajectory of airway obstruction and asthma development after 4 years of age.

Methods: We evaluated 52 preterm infants who had undergone both tidal breathing flow-volume loop (TBFVL) and multiple-breath washout (MBW) analyses in infancy and spirometry after the age of 4 years. We evaluated the association between pulmonary function parameters in infancy and childhood and the pulmonary function trajectory until 13 years of age and compared the changes in this trajectory according to pulmonary function parameters in infancy.

Results: Time to peak expiratory flow/expiratory time (T_PEF/T_E) in infancy was associated with FEV₁, FEF_25-75, and dysanapsis ratio in childhood and differed according to level of airway obstruction assessed by FEV₁, FEV₁/FVC, and FEF_25-75, an asthma development. T_PEF/T_E was a significant predictive factor for airway obstruction and asthma after 4 years of age, after adjusting for sex, extreme prematurity, duration of supplementary oxygen and mechanical ventilation, and recurrent wheezing during infancy. In premature infants with lower T_PEF/T_E, subsequent pulmonary function parameters remained low until 13 years of age.

Conclusion: In preterm infants, T_PEF/T_E could be useful to predict airway obstruction and asthma after 4 years of age and even a lower pulmonary function trajectory until 13 years of age. This information may help clinicians to provide lifelong care for pulmonary morbidity in children and adolescents born preterm.