Performance Comparison of Strain Sensors for Wearable Device in Respiratory Rate Monitoring

摘要

Respiratory rate (RR), a clinical sign of ventilation, should be measured and recorded periodically for patients on acute care. Among the other common vital signs, a change in RR can be used as the first sign of deterioration and can avoid the possibility of missing the trends' identification as occurs in intermittent monitoring. Meanwhile some devices have experiences in false detection due to the different body motions. Hence, this study aims to develop a continuous RR monitoring with accuracy improvements using wearable sensors and data recording. In this RR monitoring work, we compared the performances of the flex sensor (2.2" in size) and the force-sensing resistor (FSR402) by placing them on the abdomen of a relaxing subject using a belt for 6 h every 10 min. The monitoring data were not only displayed on a smartphone but also stored on firebase platform. The system therefore took the advantages of a web service architecture to send, retrieve, and access data from the cloud. The comparison results of the flex and the FSR402 sensors due to the average RR differences (and the mean average error) compared to the breath manual count are 0.30 bpm (0.90 bpm) and 1.45 bpm (2.25 bpm), respectively. In this study, we show a way to improve the sensor performance by automatically adjusting the sensitivity of the strain sensors for adapting the RR measurement on abdomen of the test subject. Furthermore, this study demonstrates that the system is able to measure and fast transmit the RR data as the monitoring process using the IoT Firebase platform and that the performance of the flex sensor provides the possibility of further development and improvement in obtaining much better result.