A new method to model change in cutaneous blood flow due to mechanical skin irritation part I: comparison between experimental and numerical data.

Mechanical skin irritation creates vasodilation. Vasodilation of vascular networks induces increase in blood volume and blood velocity. Both can be measured by Laser Doppler Velocimetry. We propose in this article a method permitting comparison between experimental and numerical results. Experimental data was obtained by Laser Doppler Velocimetry. Numerical results were obtained by a continuous model of the vascular network. The model consists of three layers. First and last layer are described by anisotropic and heterogeneous porous media. They represent the irrigation and the drainage of the vascular system. The intermediate layer is described by a lumped parameter model that does not permit horizontal fluxes. All vessels are compliant. The permeabilities depend on the volumes of the specific layer. Skin irritation is modeled by a change in compliance of small arterial blood vessels. The comparison between experimental and numerical data is based on the model proposed by Bonner and Nossal [1981. Model for laser Doppler measurements of blood flow. Appl. Opt. 20, 2097-2107]. The model describes the Doppler frequency spectrum S(omega) as a function of the optical phenomena creating the frequency shift. The comparison is based on the model of the first moment M1 approximately integralomegaS(omega)domega. The variables of the first moment can be determined by results of the numerical model. We have shown, that it exists a linear relation between the change in compliance and the following increase in first moment. Using this linear relation experimental and numerical data can be compared.