RT Journal Article SR Electronic T1 Use of novel tidal breathing monitoring device to detect methacholine challenge test responders JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 4367 DO 10.1183/13993003.congress-2022.4367 VO 60 IS suppl 66 A1 A Zachariades A1 I Shafran A1 N Bachar A1 N Danino A1 G Shuster A1 W Voigt YR 2022 UL http://erj.ersjournals.com/content/60/suppl_66/4367.abstract AB Background: Monitoring lung function of asthmatics heavily relies on difficult to perform spirometry, thus passive and seamless monitoring solutions are warranted. However, the possibility to reliably detect clinical changes among asthmatics by monitoring tidal breathing remains unclear.A preliminary methacholine challenge test (MCT) study was performed to evaluate how tidal breathing parameters measured by a novel wearable device (SenseGuard™) compare to FEV1 and whether they can differ between MCT responders and non-responders.Methods: 35 subjects suspected of asthma underwent MCT and were classified as responders or non-responders according to ATS guidelines. During MCT, they underwent tidal breathing measurements and parameters such as RR, inspiratory time (Tin), expiratory time (Tex), no-flow time between breaths (Trst), total breath time (Ttot), and the corresponding ratios were calculated in the baseline, methacholine doses and recovery phases.Results: FEV1 max. response change between responders (n=18) and non-responders (n=17) was significant (p<0.001), with a reduction of 22% and 3%. Similarly, the change in the novel biomarkers Tex/Ttot and Trst/Ttot between the groups was significant (p<0.02), with an increase of 31% and a decrease of 51% for the responders, while statistically insignificant for the non-responders. The remaining parameters did not change for both groups.Conclusions: Tidal breathing parameters measured by the novel device can reliably detect changes in breathing pattern during MCT. Given the current findings, we hypothesize that this technology might be feasible to monitor clinical changes in asthmatic patients in general. Further studies are warranted.FootnotesCite this article as Eur Respir J 2022; 60: Suppl. 66, 4367.This article was presented at the 2022 ERS International Congress, in session “-”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).