Impulse oscillometry in the evaluation of non-cystic fibrosis bronchiectasis in adults: A systematic literature review.

Background: Non-cystic fibrosis bronchiectasis (NCFB) is a chronic respiratory disease marked by irreversible airway dilation, persistent inflammation, and recurrent infections. Impulse oscillometry (IOS) assesses lung function non-invasively, particularly in patients unable to perform spirometry, but its role in NCFB remains underexplored.

Research question: This systematic review examined the role of IOS in adults with NCFB, focusing on diagnostic value, correlation with disease severity, airway reversibility prediction, and associations with exacerbations, hospitalisations, and mortality.

Study design and methods: A systematic literature search in PubMed, Scopus, Web of Science, and Cochrane databases was performed in January 2025, following PRISMA guidelines. Eligible studies assessed IOS in adult NCFB and reported associations with clinical, radiological, or functional outcomes. Study quality was assessed using the Newcastle-Ottawa Scale adapted for cross-sectional studies.

Results: Seven studies were included. IOS was more sensitive than spirometry in detecting small-airway dysfunction, particularly in early disease. Several IOS parameters correlated with radiological and severity scores, though findings were heterogeneous. Associations with exacerbations and hospitalisations were inconsistent. One study suggested R5-R20 may predict bronchodilator response. IOS parameters appeared stable across disease stages.

Conclusion: IOS may complement conventional assessment of NCFB, especially for small-airway evaluation, but standardisation and longitudinal research remain necessary.