Numerical simulations of the microvascular fluid balance with a non-linear model of the lymphatic system

35/2018

Numerical simulations of the microvascular fluid balance with a non-linear model of the lymphatic system

Sunday 3rd June 2018

Possenti, L.; Casagrande, G.; Di Gregorio, S.; Zunino, P.; Costantino, M.L.

Fluid homeostasis is required for life. Processes involved in fluid balance are strongly related to exchanges at the microvascular level. A computational model is adopted to study such phenomena mainly relating to oncology, in particular tumor perfusion and related treatments. As far as we know, none of those mod- els consider a physiological non-linear behavior for the lymphatic system. We develop a computational model that consists of a network of straight cylindrical vessels and an isotropic porous media with a uniformly distributed sink term acting as the lymphatic system. In order to describe the lymphatic flow rate, a non-linear function of the interstitial pressure is defined, based on literature data on the lymphatic system. The proposed model of lymphatic drainage is compared to a linear one, as is typically used in computational models. To evaluate the response of the model, the two are compared with reference to both physiological and pathological conditions. A non-physiological behavior is observed when using the linear models of lymphatic drainage but not when using the proposed non-linear model; in addition, differences in local fluid dy- namics are found. This work highlights the key role of lymphatic drainage and its modeling when studying the fluid balance in microcirculation for both to physiological and pathological conditions, e.g. uremia.

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revised manuscript sent to Microvascular Research