DETERMINATION OF PULMONARY MEAN TRANSIT-TIME AND CARDIAC-OUTPUT USINGA ONE-DIMENSIONAL MODEL

In this work, we show that a one-dimensional model of the blood flow a cross the lungs can reproduce the evolution of a bolus versus the time . Solving the differential equation governing the bolus concentration in the framework of this model, we determine the solution which fulfil ls Gaussian initial boundary conditions. An effective parameter relate d to the ratio of a diffusion coefficient to the square of the mean sp eed of the flow is defined. The determination of its numerical values following a semi-empirical approach enables us to know accurately the mean transit time and the cardiac output. The results have been compar ed to other methods, and were found in good agreement. Such an approac h could be of interest in all studies where the knowledge of flow-incl uding micro-circulation-is needed. (C) 1996 Society for Mathematical B iology