Preterm babies have abnormal total airway resistance regardless of BPD status, study reveals assessment by impulse oscillometry system

A new study published in the Respiratory Medicine journal revealed that preschool children born extremely preterm (at or before 28 weeks) often exhibit abnormal lung function, regardless of whether they were diagnosed with bronchopulmonary dysplasia (BPD). This prospective study evaluated the respiratory health of children from the Centre Intercommunal de Créteil in France born between 2006 and 2012 by focusing on their lung function, respiratory symptoms, and growth at age 4.

This research included 136 extremely premature children, of whom 26 (19%) had BPD. The primary goal was to analyze their lung function, specifically looking at airway resistance using the impulse oscillometry system (IOS) which measures respiratory resistance and reactance at different frequencies, providing insight into lung health. The study compared these metrics between children diagnosed with BPD and the ones without.

The results indicated that an overwhelming majority of the children (76%) had elevated respiratory resistance at 5 Hz (R5), a measure of total airway resistance, regardless of BPD status. The R5 values were above the 95th percentile for the reference population which meant these children expressed higher resistance in their airways than the average population. Also, the mean R5 z-score, and a statistical measurement indicating deviation from the norm, was 2.1 by signifying a notable abnormality in airway resistance among these extremely preterm children.

However, while total airway resistance was generally high, respiratory resistance at 20 Hz (R20), which reflects more central airway resistance, fell within the normal range (mean z-score of 1.1). Reactance at 5 Hz (X5) did not significantly differ between children with and without BPD by suggesting that airway resistance abnormalities were consistent across groups. Even after treatment with bronchodilators no significant changes in respiratory resistance were observed in either group.

The study also recorded that asthma-like symptoms, such as wheezing and difficulty breathing, were common among the cohort, with a prevalence rate of approximately 30% by age 4. This finding indicated a high level of respiratory morbidity among extremely preterm children, irrespective of BPD diagnosis by highlighting the need for early and regular lung function assessments in these patients. Overall, the study suggests that the impulse oscillometry system is a valuable, non-invasive tool for early lung function assessment in young children born prematurely.

Source:

Delestrain, C., Halitim, K., Tauzin, M., El Jurdi, H., Jung, C., Hau, I., Durrmeyer, X., Decobert, F., Delacourt, C., Madhi, F., & Epaud, R. (2024). Pulmonary Function using Impulse Oscillometry System and Clinical Outcomes at Age 4 Years in Children Born Extremely Preterm with or without Bronchopulmonary Dysplasia. In Respiratory Medicine (p. 107845). Elsevier BV. https://doi.org/10.1016/j.rmed.2024.107845