THE RECOVERY OF INJECTED DYE AND THE YIELD OF BLOOD CELLS BY PERFUSION OF THE CARDIOVASCULAR SYSTEM IN BARBITALIZED DOGS

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Abstract
Barbitalized, splenectomized dogs were given intravenous injn. of the dye T-1824 and after a period of 20 mins., necessary for detn. of plasma vol., a perfusion of the cardiovascular system with 4% gelatin soln. was started. The perfusion was done by withdrawing, from an artery, 10 ml. of blood/Kg. of body wt., and immediately injecting intravenously an equal vol. of the gelatin soln., repeating the bleeding and replacement every 3 mins. The yields of dye and blood cells, obtained in the successive bleedings, declined at constant exponential rates which, by extrapolation to complete disappearance, made it possible to calculate the total amts. available for perfusion within the cardiovascular system. The cells usually disappeared more rapidly than the dye from the drawn blood. The total values of dye averaged 77.61% of the amt. of dye injected initially (varying from 62-88%), and the total values of cells averaged 83.94% of the initial cell vol. calculated from the plasma vol. and the hematocrit (varying from 66-99%). There is a nearly perfect correlation between these percentage values of dye and cells, the coefficient being 0.973. Two possible interpretations are given: (1) The perfusion method used in this study yields only a fraction of the total vascular content. (2) The ratio between the true circulating cell vol. and the cell vol. calculated from the hematocrit and the plasma vol., depends upon the percentage of the injected dye which leaves the vascular system undetected, during the so-called "mixing period.".