Reactance inversion in moderate to severe persistent asthma: low birth weight, prematurity effect, and bronchodilator response

Abstract

Introduction

Reactance inversion (RI) has been associated with impaired peripheral airway function in persistent asthma. However, there is little to no data about the difference between asthmatic children with and without RI. This study aimed to detect clinical and lung function differences in moderate-severe asthmatic children with and without RI.

Methods

This study was conducted between 2021 and 2022 in asthmatic school-age children. Impulse oscillometry (IOS) and spirometry were performed according to ATS/ERS standards.

Results

A total of 62 patients, with a mean age of 8.4 years, 54.8% were males and were divided into three groups: group 1 (32.3%) with no RI, group 2 (27.4%) with RI but disappearing after bronchodilator test and group 3 (40.3%) with persistent RI after bronchodilator test. Children in groups 2 and 3 had significantly lower birth weights than in group 1. Group 2 had lower gestational age compared to group 1. FEV₁ and FEF_25-75 of forced vital capacity were significantly lower in groups 2 and 3. In group 3, R5, AX, R5-20, and R5-R20/R5 ratios were significantly higher. Bronchodilator responses (BDR) in X5c, AX, and R5-R20 were significantly different between groups and lower in group 3.

Conclusion

RI is frequently found in children with moderate-severe persistent asthma, particularly in those with a history of prematurity or low birth weight. In some patients, RI disappears after the bronchodilator test; however, it, persists in those with the worst pulmonary function. RI could be a small airway dysfunction marker.

Keywords:

• Asthma
• low birth weight
• lung function
• oscillometry
• prematurity
• school-age children
• reactance inversion

Acknowledgments

We would like to thank Professor Hans-Jürgen Smith of the Research in Respiratory Diagnostics, Berlin, Germany for helping us with literature to understand this pathophysiological phenomenon.

Disclosure statement

The authors declare no conflict of interest. The authors alone are responsible for the content and writing of this article.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.