Blood volume changes in cyanotic congenital heart disease and polycythemia rubra vera.

IT IS WELL KNOWN that in polyeythemia rubra vera the total blood volume increases as the hematocrit level rises beyond approximately 55 per cent.1-2 This increase masks the extent of the polycythemia and insures that the plasma volume is not greatly diminished despite an increase in red cell volume to twice or three times the normal value. The changes in adults suffering from cyanotic congenital heart disease have not been precisely defined. It is less easy to compare the blood volume in this condition with expected normal values because the limits of the normal blood volume are poorly defined by reference to height or weight.3 Statistically valid limits of blood volume have been determined in adult subjects by means of height, weight, girth, and fat thickness.3 In this paper patients of adult stature suffering from polycythemia rubra vera and from congenital heart disease are compared with normal adults.