A Wearable Thermoelectric Device for Closed-Loop Pulmonary Function Monitoring, Screening, and VR-Assisted Rehabilitation

Early screening for chronic obstructive pulmonary disease (COPD) is critical due to the progressive and debilitating nature. Preliminary diagnosis typically relies on pulmonary function tests, particularly the ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC). However, conventional spirometers are often bulky and non-portable, while most existing portable devices can only measure a single parameter, such as FVC, thereby limiting comprehensive assessment. To address these limitations, an integrated wearable system was proposed for both monitoring and rehabilitation training. This system is based on the innovative thermoelectric-airflow inversion (TAI) model, which quantitatively correlates convective heat transfer with thermoelectric voltage to reconstruct airflow velocity and volume in real time. The developed thermoelectric smart mask enables simultaneous measurement of two key obstructive indicators (FVC and FEV1) and automatically evaluates COPD risk via the FEV1/FVC ratio, alerting users to seek medical consultation when abnormalities are detected. In terms of performance, the device demonstrates a measurement accuracy of 99.10% and a coefficient of determination (R2) of 0.9947 compared to a commercial spirometer. Furthermore, the incorporated virtual reality assisted rehabilitation system was developed, yielding an average FVC improvement of 5.87% across three participants after one week of interactive training. Enabled by the TAI framework and a closed-loop multi-parameter design, this platform provides an intelligent, quantitative, and continuous solution for respiratory healthcare and rehabilitation.