This study will generate data to characterise the tidal breathing patterns and parameters with Thora-3Di™ against spirometry FEV1/FVC and %predicted. Subjects will have a Part A visit (Development Phase) to develop algorithms for COPD diagnosis. At Part A visit, subjects will have two 5-minute SLP measurements (Pre and Post bronchodilator). The SLP measurement should be performed prior to standard lung function tests with minimal impact on clinical time and no change to hospital attendance. Also, subjects will be asked to report concomitant medications and adverse events and fill in COPD assessment test (CAT™).
