Estimating total peripheral vascular resistance by in vivo microscopic observation of arteriolar diameter

Abstract

Arterioles, the smallest arteries having a diameter less than 100μm regulate the systemic blood pressure (P) and blood flow(Q). The relation between blood pressure and flow can be represented by Poilleuille's law as Q=P/RT (RT: total peripheral vascular resistance). On the other hand, the blood flow resistance in the arterioles (Ra) is represented as Rv = 8μL/nr 4 [μ: viscosity, r: arteriolar radius]. In the present study, the total peripheral vascular resistance (RT) has been optained by direct measured blood pressure and blood flow in rat carotid artery, whereas the flow resistance in the arterioles has been determined by direct observation of microcirculation simultaneously. To compare these values of resistance we evaluated whether Poilluille's law can be applied to in vivo microcirculati