Novel Method for Recording High Frequency Human Skin Temperature Oscillations

Circuitry solution has been developed to create a prototype of the system for the registration of the high frequency human skin temperature oscillations. As they connected with blood circulation, such method allowing in the future to provide the registration of the pulse wave signal, for measuring heart rate in portable devices like smart watches and fitness bracelets. The miniature semiconductor chip diodes sensor has been used. The electronic system for the calibration of the device has been designed. For providing operation of the system in a full voltage range using the automatic set has been used for the maintenance of the operating point and of the necessary slope of the conversion factor (Volts / °C). The structural and circuit diagram has been developed. They consisted of two parts: the remoted preamplifier with the temperature sensor and the main block including all the other digital and analog parts. The developed system has following technical characteristics: the temperature resolution to be 0.01 °C and the thermal time constant of the sensor 0.05 s. The registration system testing has been performed in two ways: in a thermostat and on the human skin surface. Device contains plethysmo- and ECG-channels for obtaining data on the phases of cardiac cycles and synchronous analysis of physiological processes. The cross correlation coefficient between the temperature oscillations and the pulse wave signals laid in the diapason from 0.53 to 0.65

Evaluation of PWPT-based method for cuffless monitoring of arterial blood pressure

Blood pressure is not a constant, it is continuously changing value which could go beyond of the physiological norm. This phenomenon is called the variability of blood pressure allowing to track changes in the circulatory system functioning. This variability could indicate the presence of various diseases and risk of damage of the vital organs. Nowadays, the only widespread way for accurate assessment of long-term variability is to use standard blood pressure monitor for measuring blood pressure and write down the results manually to the patient diary which is not too convenient while controlling this values is very important both in the treatment of patients with hypertension or desease prognosis. Recently, the interest in indirect methods and systems for blood pressure measuring has grown significantly because of their prospects. This paper reviews the Frank's Windkessel model which describes the interaction of blood pressure and pulse wave velocity. The simultaneous effect of changes in blood pressure and quasiperiods imitating heart rate on changes in pulse wave propagation time is studied. The obtained simulation output have been used for testing of the method of indirect evaluation of blood pressure. Besides, achieved practical experimental results are presented