Feasibility Study: A stand alone, 3D printed respiratory oscillometer powered by Raspberry Pi suitable to detect airway obstruction in COPD.

<bold>Background:</bold> Case finding and diagnosis of COPD still remain challenging in primary healthcare settings. <bold>Aim:</bold> Develop a stand-alone solution based on respiratory oscillometry that is suitable for use in primary care and helps in case finding by providing disease specific information. <bold>Methods:</bold> 1) We developed a prototype using a 3D printed pneumotach and airflow channel including a digital differential pressure sensor. Signal generation, hardware control, signal processing, data collection and GUI were programmed using a single-board computer (Raspberry Pi 4) and a touchscreen display. 2) Technical comparison was performed with a commercial respiratory oscillometry device (Resmon Pro v3.0, Restech, Milan, Italy) using resistant test loads (0 to 14 hPa.s.L-1) to simulate differing amounts of airway restriction. 3) Measurements were performed in adult volunteers (± COPD) recruited at the outpatient area of the hospital. Anthropomorphic and clinical data were collected incl spirometry parameters. Linear regression and Bland-Altman analysis were used to evaluate bias between the devices. <bold>Results:</bold> Measurements were obtained from healthy controls (N=8) and individuals with COPD of different severities (N=11). Resistant testloads showed good correlation at 5 and 10Hz (slope=1, intercept=0.1/0.2). A bias was detected in clinical testing at 5Hz and 19Hz (slopes=0.75-0.9). <bold>Conclusion:</bold> Proof of concept study of BREAZ prototype shows non-inferiority over a commercial oscillometry device using mechanical resistant testloads up to 14 hPa.s.L-1 as well as in detecting resistance and reactance changes in patients with COPD.