Impact of Different Algorithms on Evaluating Changes in Oscillometry Parameters During Quiet Breathing

<bold>Aims:</bold> Changes in oscillometry parameters during breathing provide valuable insights but are influenced by flow, volume, and artifacts. These factors may affect different computation methods: considering resistance (Rrs) and reactance (Xrs) values at end-inspiration/expiration has the theoretical advantage of obtaining values independent of flow pattern and reducing the impact of nonlinearities. This study evaluates the reproducibility/stability of oscillometry parameters computed as <italic>a</italic>) the mean of the entire inspiratory/expiratory phase and <italic>b</italic>) the values at end-inspiration/expiration. <bold>Methods:</bold> We analyzed 523 triplicate oscillometry measurements (ResmonPRO, Italy) from the Austrian LEAD study, including participants aged 18–86 years (43% female). Among them, 46 (8.8%) reported diagnosed diseases, and 111 (21.2%) reported respiratory symptoms. Inspiratory/expiratory parameters and the coefficient of variation (COV) were computed using the two methods for each variable. <bold>Results:</bold> <fig><object-id>erj;66/suppl_69/PA643/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> As expected, Rrs is higher in the presence of flow (<italic>a</italic>-<italic>b</italic>>0, Table). Differences between parameters computed by methods <italic>a</italic> and <italic>b</italic> were correlated to flow for inspiratory parameters but not for expiratory ones. Method <italic>a</italic> lead to lower COV. <bold>Conclusions:</bold> Even if less affected by the respiratory flow, Rrs and Xrs measured at end-inspiration/expiration resulted in higher COV.