The microcirculatory bed is a part of the vascular system, in which such diseases as atherosclerosis, diabetes, cancer, kidney and heart disfunctions can manifest themselves in the initial stages. For this reason, assessment of blood microcirculation (movement of blood in capillaries and adjacent micro vessels) and microcirculatory disorders is relevant in modern clinical practice.
Researchers all over the world are developing and improving tools for reliable and non-invasive monitoring of blood flow in various parts of the body under various conditions, and systems capable of recording all vascular elements of the blood, i.e. arterial, capillary, and venous components. Physiological activity causes changes of the body surface temperature in a wide amplitude and frequency range. The activity is linked with heartbeat pulsations that have a ridiculously small amplitude and a maximum frequency of temperature oscillations. Therefore, it is relevant to develop methods and tools for studying blood flow oscillations based on the results of skin surface thermometry.
Researchers from Saint Petersburg Electrotechnical University “LETI” and their colleagues from Institute of Experimental Medicine have set out to develop a technical solution aimed at achieving maximum resolution and high operational properties of a medical thermometer.
LETI researchers proposed a prototype based on two main approaches – original analog-digital scheme of the operating point (OP) automatic adjustment to ensure the maximum dynamic range for recording smallest temperature oscillations when the constant level of the body surface temperature changes, and automatic gain control circuit to ensure the dynamic range of temperature oscillations registration. Thermal time constant of 0.05 s is achievable by using a semiconductor diode sensor in an open-frame design. Especially for testing the developed prototype, miniature thermostat works on Peltier elements to calibrate and calculate absolute temperature values was designed and produced.
‘To conduct laboratory studies, an experimental setup has been developed. It includes an original wireless device for recording temperature oscillations and, a data acquisition system from BIOPAC to simultaneously record electrocardiograms (ECG) and pulse wave (PW) signals of high quality. As a result, it was concluded that this method is suitable for blood microcirculation investigations’ – as explained by Oleg A. Markelov , Director of the Advanced Wireless Technologies R&D division.
The result of research is a well-tested and patented biomedical thermometer. The researchers are now making plans to develop scientifically based recommendations for its practical application as a unique method for diagnostic and estimation the functional capabilities of the human body.
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High Precision Human Skin Temperature Fluctuations Measuring Instrument
14-Jun-2021