Method of obtaining arterial elastic coefficients in totally perfused animals

¹ Department of Physiology, University of Minnesota Medical School, Minneapolis, Minnesota

Calculations of arterial elastic coefficients of dogs under conditions of total body perfusion have been made by utilizing the pressure data obtained from steady state perfusion and inflow stoppage. This was done by finding the first derivative of the pressure-time curve after inflow stoppage and evaluating this at the starting time of the transient. This "zero" time slope gave the value of the elastic coefficient divided by the resistance at the instant of inflow stoppage, and multiplying this ratio by the resistance evaluated from the immediately preceding steady state conditions gave an estimate of the elastic coefficient, E, of the arterial tree. Drugs were used to alter the resistance, and this permitted an estimate of E under various conditions. The value of E appeared to be a function of arterial pressure, and the value at a pressure of 124 mm Hg was 4,080 dynes/cm⁵.