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In the last 30 years the study of microcirculation has become one of the central problems of experimental and clinical medicine. This can be explained by the fact that the transport function of the cardiovascular system is eventually implemented in the capillary bed providing the transcapillary exchange necessary for normal tissue homeostasis.Experimental and clinical research into this fundamental problem is essential for the solution of such important problems of practical medicine as treatment and prophylaxis of general and regional blood circulation disorders, study of pathogenesis of many diseases and search for new methods of treatment of radiation sickness, treatment of different types of inflammation and tumor metastases, and a number of problems of space medicine. This is a challenge for the development of new methods of study of microcapillary bed, assessment of their efficacy, and speedy introduction into practical health service.A variety of methods of determination of skin capillary permeability, such as mechanical tests, the venous congestion method, clearance, etc., are presently known. However, all these methods are either invasive or provide little information [3, 41.A new noninvasive impedance method was proposed to determine the permeability of skin capillaries, which involves measurement of the electric resistance of a skin segment before and after exposure to a negative pressure [1]. The clinical application of this method [2] showed that a more fundamental approach to the interpretation of the examination results is necessary. Various factors affecting skin capillary permeability were analyzed. The most substantial factors were taken into account for simulating processes in the microcapillary bed. Three models of processes in the skin capillary layer were considered to obtain a comprehensive idea of changes in the skin capillary permeability.In the first model, a skin segment exposed to a negative pressure was considered as an axially symmetric plate to simulate the deformation of the segment. A theoretical equation for the dependence between the maximum flexure of the skin segment and pressure in a cuvette was obtained taking into account the negative pressure limits:Eh:where p is pressure, R c is the radius of the cuvette, E is Young's modulus of the skin, u 0 is the maximum skin flexure, h s is the skin thickness, v is Poisson's coefficient.The results of the simulation allow the estimation the permissible values of negative pressure and obtain a sufficiently reliable pattern of processes in the skin segment taking into consideration only average mechanical parameters of skin.The second and third models consider the capillary permeability on the microcapillary level. A capillary is considered as a porous elastic tube of a finite length.In the second model, the pressure dependence of the flow through the porous wall of the capillary is simulated. It is assumed that all pores in the capillary walt are identical and cylindrical in shape.

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