BLOOD VOLUME IN NORMAL INFANTS AND CHILDREN

Abstract

Blood volumes were determined by the dye method on infants and children. The plasma volume per kilo, of body weight rose from 50 to 62 ml. during the 1st year of life and returned to 50 ml. by the 4th year, thereafter remaining constant. The plasma volume per sq. m. of surface area rose from 750 to 1100 ml. during the 1st year and thereafter slowly to 1375 ml. by the 12th year. The proportion of red cells is about 30% except during the first weeks of life, when it is much higher. However, variations in the proportion of red cells are so great that one can not predict the whole blood volume accurately. A mechanism of water transport is described which accounts for some of the variation of plasma volume.