Comparative evaluation of the parameters of laser doppler flowmetry of the skin of healthy persons using devices of various modifications

This is the authors' abstract. We don't add key points for this paper.

Objective . Evaluation of differences in the values of the recorded perfusion parameters of two structurally different LDF devices in a group of healthy people of working age. Materials and methods. The study included 53 relatively healthy volunteers (m/f – 30/23) of working age (43±9 years). The study of microcirculation was carried out in the supine position on the back surface of the left forearm, simultaneously with two LDF devices: a LAKK-02 device with a fiber-optic data transmission and reception probe and a portable LAZMA-PF analyzer. The study included measurement of basal perfusion, respiratory constrictor test (DP), constrictor test with venous occlusion (VO), and dilator test with arterial occlusion (AO). Results . Relative to the stationary variant, the portable device demonstrates statistically significant differences, namely, higher values of the tissue perfusion level – 4.27 [3.82; 5.54] PU and 3.44 [3.03; 4.11] PU, respectively, as well as the amplitude of respiratory fluctuations in blood flow 0.08 [0.06; 0.13] PU and 0.07 [0.06; 0.09] PU, and lower values of the amplitude of pulse oscillations 0.22 [0.19; 0.26] PU and 0.26 [0.2; 0.31] PU and constrictor activity of microvessels in DP – 21.5% [19.2; 29.4] and 40% [29; 51] and VO – 27% [20; 33] and 47% [42; 56] respectively. The statistical significance of differences in values (p<0.05) was confirmed by One-way ANOVA. For a more complete understanding of the results obtained, a numerical simulation of the propagation of optical radiation of two devices in the skin was carried out. The simulation results showed that the probing volume of the skin and the penetration depth of the radiation in a portable device are greater than in a device with a fiber optic probe. The results obtained suggest the predominance of the venular link of the skin microvasculature in the formation of the reflected signal in the portable version of the LDF device compared to the device with a fiber optic probe. Conclusion . The wavelength and design features of LDF devices affect the results of the study due to the different diagnostic volume of the skin, which is recommended to be taken into account in scientific and clinical work.