At-home validation of a non-contact, radar-based breathing monitor for long-term care of patients with respiratory diseases: A proof-of-concept study

Long-term monitoring of respiratory rate (RR) is an important component in the management of chronic respiratory diseases (CRDs). Specifically, predicting acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is of significant scientific and clinical interest. This study aimed to evaluate the long-term validity of a novel contactless sleep monitor (CSM) in the home environment of CRD patients receiving ventilatory support. Additionally, we assessed patient acceptance, device usability, and RR fluctuations associated with AECOPD to establish a robust foundation for future research.In this prospective proof-of-concept study, nineteen patients requiring non-invasive ventilation (NIV) were provided with the CSM in their home environment for six months and seven patients requiring invasive mechanical ventilation (IMV) for one month. The primary indication for NIV therapy was chronic obstructive pulmonary disease (COPD).The CSM was validated under real-life conditions by comparing its nocturnal RR values with software data from both types of ventilators. Acceptability and usability of the sensor were assessed using a questionnaire. Additionally, COPD exacerbations occurring during the study period were analyzed for potential RR fluctuations preceding these events.Mean absolute error (MAE) of median RR between the NIV device and the CSM, based on 2326 nights, was 0.78 (SD: 1.96) breaths per minute (brpm). MAE between the IMV device and the CSM was 0.12 brpm (SD: 0.52) for 215 nights. The non-contact device was accepted by the patients and proved to be easy in use. In some of the overall only 13 cases of AECOPD, RR time courses showed variations of increased nocturnal respiratory activity a few days before the occurrence of such events.The present CSM is suitable for valid long-term monitoring of nocturnal RR in patients' home environment and is well accepted by the patients. The exploratory findings related to AECOPD events may serve as a starting point for larger studies aimed at developing robust prediction rules.