Laser flowmetry of microcirculation of the finger depending on the external temperature and the limb position

Abstract

Introduction. The use of laser Doppler flowmetry (LDF) makes it possible to assess the condition and disorders of blood microcirculation, improving the quality of diagnosis of various cardiovascular diseases. Additional functional tests with laser flowmetric measurements are used to assess the state of the mechanisms that regulate the tissue blood flow. Objective. To identify patterns of blood flow changes in the microcirculatory bed when combining a postural test and a change in air temperature. Materials and methods. The study was conducted on a group of 20 subjects, which included an equal number of girls and boys aged 21–23 years, who were considered healthy and did not have cardiovascular diseases. The experiment was carried out in two stages: first in a room with an air temperature of 201 °C, then at 301 °C. To assess the difference in data between arm positions within the same study phase at the same temperature, the Student’s t-test was used to compare quantitative variables in two dependent samples. The Wilcoxon test was used to assess statistical differences in data for the same hand position but at different air temperatures. Changes were considered statistically significant at p<0.05. The subjects were measured the microcirculation of peripheral blood vessels on the phalanx of the finger in three positions relative to the level of the heart using a portable laser Doppler flowmeter LAZMA PF (Russia). Results. It is shown that an increase in ambient temperature leads to an increase in the difference in microcirculation of peripheral vessels when the arm position changes relative to the level of the heart. When a person is in a room with a temperature of 301 °C, dilation of blood vessels and changes in their tone occur, which explains the increase in microcirculation values in relative perfusion units. Conclusions. The results of the study showed an increase in statistically significant differences according to the Student’s t-test between the different hand positions with increasing room temperature (p<0.0001). In a comparative sample between the first stage (at an air temperature of 20±1 °C) and the second stage of the study (at an air temperature of 30±1 °C), statistically significant results (p<0.001) were obtained according to the Wilcoxon test for the hand position at the heart level and the raised arm.