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Article

Personal Medical Wearable Device for Distance Healthcare Monitoring X73-PHD

Korsakov I. N., Kuptsov S. M., Raznometov D. A.

Distance patient monitoring during daily activity can provide medical information from different sensors . Recording of related cardiac signals such as ECG, respiration and also other information such as body motion can improve diagnosis and monitor the evolution of many widespread diseases. Key-issues for portable or even wearable personal healthcare devices (PHD) are: power consumption, longterm sensors, comfortable wearing, easy and wireless connectivity. For example, hearing aids batteries you have to change every 7-10 days, but wireless sensor for securities system you don't need to change it for 3-5 years that is very convenience. Power consumption of wearable PHD depend on what kind of sensors, which technologies of communication and processor do you use and function that it calculated in real time, temperature, humidity and many other factors. To improved the comfort of using PHD we need reduce the weights of device, reduce the power consumption - move some functionality from device to host computer (application server), improve recharged batteries ( use wireless charger), used new materials for ECG electrodes. The ECG front end (based on TI AD1293 chip) offers ultra-high input impedance allowing use of dry, long-lasting electrodes such conductive rubbers or novel textile electrodes that can be embedded in clothes. A small size digital ADXL345 3-axes accelerometer was also integrated. Patient monitor incorporate a 16 bit low power microprocessor that controls 24-bit ADC of signals at programmable sampling frequencies (e.g. 500 Hz) and drives, digital temperature sensor and the Bluetooth BLE module from Bluegiga capable to reliable transmit real-time signals within 20 m range. Added accelerometer to personal healthcare device allows new functionality such as fall detector, which very important for elder people and help to understanding people activities during ECG recording. To reduce power consumption the accelerometer can used as a start / stop sensor for ECG recording and other measurements. Another useful medical parameter that we can monitor is the arterial blood pressure. Measurement of arterial blood pressure (BP) involves obtaining the systolic blood pressure (SBP) and diastolic blood pressure (DBP), defined as the highest and lowest pressures during a cardiac cycle. The golden standard to measure BP is the ausculatory method, here a specialist inflates a cuff around the arm, and uses a stethoscope to determine SBP and DBP. Oscillometric techniques are based on the same principle, but are intended for home use. These two methods require the use of a cuff, which is bulky, costly, and does not allow continuous monitoring. We propose an adaptive algorithm to estimate SBP and DBP without using a cuff, we use of peripheral oxygen (SPO2) sensor. The work was carried out with the financial support of the Ministry of education and science of the Russian Federation (the contract № 02. G 25.31.0033)