Study On Wearable Multiple Physiological Parameters Monitoring System

With the rapid development of wearable devices and mobile health care recently, intelligent devices like watch style, wristband style and smart shirt have emerged in an endless stream. However, most of these devices only have simple functions that could measure several healthy parameters. In this paper, we developed a new wearable multiple physiological parameters monitoring system which can monitor physiological parameters such as electrocardiograph(ECG), blood pressure(BP), blood oxygen saturation(SpO2) and breath rate without influencing the normal activities users. To some extent, this device could replace bedside monitoring and be used in long-term monitoring on the hypertension, heart attack and apnea patients at home.It is easy to monitor ECG, breath rate and Sp O2 continuously, except for BP because the common blood pressure measurement method is Korotkoff-Sound Method. It is noninvasive and intermittent. Nevertheless, vascular unloading technique and arterial tonometry method can measure blood pressure noninvasively and continuously, they still can’t get rid of cuff and are not suitable for wearing in a long time. Blood pressure measurement based on pulse wave translation time(PWTT) or velocity(PWV) might be a better choice. We did research as follows in this article.1. The design approach of the experimental prototype device was described firstly, including wristwatch, blood oxygen fingertip and ECG collecting part. The device has advantages of small volume, few connecting lines and being worn conveniently. This device is able to collect one channels of ECG, two channels of photoplethysmography(PPG) and one channel of breath signal. The signals are sent to computer by Bluetooth and stored in computer for follow-up study after displaying on the screen.2. We had a research on noninvasive continuous blood pressure measurement based on PWTT. A relational model between PWTT and blood pressure was built based on some experiments. Finally a single-point calibration model was built to measure blood pressure noninvasively and continuously. The stability of this model was tested based on some experiments. The error of systolic blood pressure measurement is ±5.12 mmHg and diastolic blood pressure measurement is ±4.06 mmHg by the model that we studied. The result shows that this single-point calibration model has great stability within a period of time.3. The software of monitoring system is designed. The software of system is consisted of experimental prototype and software on PC. The prototype is simple to operate and the software based on PC runs stably. It can collect ECG and PPG signal synchronously and monitor heart rate, SpO2, BP and breath rate parameters continuously. The test results showed that the wearable multiple physiological parameters monitoring system can be used preliminarily.