Electrometric ph determinations: by Roger G. Bates. 331 pages, 15 × 23 cm. New York, John Wiley & Sons, Inc., 1954. Price, $7.50

Abstract

One hundred and forty-five plasma volume determinations were performed on 51 healthy premature infants between birth and 1 year of age. Two or more serial observations were made on 38 of the infants. Plasma volumes were measured with the use of T-1824. Serum iron and iron-binding capacity determinations were also made.The average blood volume at birth was found to be 109 ml. per kilogram, a value slightly higher than in fullterm infants. In the first 2 1/2 months of life there was a tendency for the plasma volume to increase as the erythrocyte volume decreased. This had the effect of maintaining the total blood volume at a relatively high level.The erythrocyte volume at birth was 45.5 ml. per kilogram (about 5 ml. higher than in full-term infants) and was close to 20 ml. per kilogram between 12 and 52 weeks of age. There was no significant correlation between erythrocyte volume and growth gain, nor between erythrocyte volume and venous hematocrit. Normal growth increments far outdistanced the expansion of erythrocyte volume.The circulating hemoglobin mass was 36.5 Gm. in the first 2 days of life; it declined 33 per cent by 4 weeks of age. At 12 weeks it was again at the value recorded in the first 2 days. Further increments were more gradual. On the basis of body weight, an abrupt fall from 20.5 Gm. per kilogram at birth to 10 Gm. at 6 weeks occurred. The average value remained between 6.4 and 8.0 Gm. per kilogram for the rest of the year. There was poor correlation between the values for hemoglobin concentration and circulating hemoglobin mass in both the neonatal period and later. The total hemoglobin iron reached its lowest level between 3 and 6 weeks of life. By the tenth week, values recorded in the first week were regained. It was concluded that erythropoiesis became active between 3 and 7 weeks after birth and that the original iron stores were adequate for hemoglobin synthesis until only about 10 weeks after birth. This explains in part the development of iron depletion and iron deficiency at an earlier age in the premature infant than in the full-term one.The results of this investigation indicate the average values of total blood, plasma, and erythrocyte volumes and of circulating hemoglobin mass of premature infants from birth through 1 year of age. It was concluded that within the limitations of the techniques used, these values are representative of an urban clinic group.It was observed that considerable variation about the mean values was present throughout the year. The average values, therefore, indicate changes that may be expected in the first year of life but should be considered specific in only a restricted sense.