THE ROLE OF OSCILLOMETRY IN ASSESSING BRONCHIAL HYPERRESPONSIVENESS TO METACHOLINE: A SYSTEMATIC REVIEW
Abstract
Oscillometry is a pulmonary function testing method that allows assessment of both central and peripheral airway mechanical properties during tidal breathing. It may provide additional information during methacholine bronchial challenge testing, however, criteria for interpreting changes in oscillometric parameters have not been standardized. Objective. To summarise data from published studies on changes in oscillometric parameters during methacholine bronchial challenge testing, their associations with airway hyperresponsiveness, and the cut-off values proposed in the literature. Methods. This systematic review was conducted in accordance with the PRISMA guidelines. A literature search was performed in the PubMed database, including studies published in English between 2016 and 2026. Original studies involving adults undergoing methacholine bronchial challenge testing were included if they reported quantitative oscillometric data or associations between oscillometric parameters and airway hyperresponsiveness. Results. Ten publications were included in the systematic review. Oscillometric parameters changed significantly during methacholine bronchial challenge testing, but these changes did not always correspond to the reduction in forced expiratory volume in 1st second (FEV1). In the largest cohort, a positive response was identified in 70.6% of participants using an increase in respiratory system resistance at 5 Hz (R5) of ≥ 40 %, compared with 37.5 % using a decrease in FEV1 of ≥ 20 %. The proposed cut-off values for increases in R5 ranged from 32.96 % to 43.8 %, while the cut-off values and diagnostic accuracy of other parameters varied. Conclusions. Oscillometry may complement spirometry in assessing the response during methacholine bronchial challenge testing. Validated cut-off values for oscillometric parameters are currently unavailable. Larger multicentre studies are required to establish them.
