The Measurement of Circulation Time by Means of an Indicator

Abstract

Mathematical studies show that the mean transit time of blood between the 2 cross sections at the inflow and outflow of a system of blood vessels can be accurately measured from the mean concentration of an indicator in these cross sections only under the following conditions: (a) The indicator is distributed at the inflow cross section so that the amount of indicator passing through an infinitesimal area divided by the flow rate through this same area is constant for every infinitesimal area of the cross section. (b) The turbulent flow of the blood at the outflow cross section results in a homogeneous velocity distribution.