Exchange transfusion in the newborn infant with fresh and "old" blood: The role of storage on 2,3-diphosphoglycerate, hemoglobin-oxygen affinity, and oxygen release

The hemoglobin-oxygen equilibrium curve and red cell 2,3-diphosphoglycerate values were measured in 29 infants before and after exchange transfusions for hyperbilirubinemia. In 12 infants the blood used for exchange was 4 to 5 days old (Group 1), while in the other 10 the blood was used within 24 hours of collection in acid-citrate-dextrose. The mean P₅₀ and the mean red cell 2,3-diphosphoglycerate were similar in both groups prior to exchange transfusion and averaged 20.0 mm. Hg and 4,250 mμm per milliliter of red blood cells, respectively. In the infants in Group 1 the mean postexchange P₅₀ fell to 17.1, rose to 23.0 at 24 hours, and was 27.9 mm. Hg 5 days later. The 2,3-diphosphoglycerate values at these times averaged 1.6, 3.1, and 6.5 mmoles per milliliter of red blood cells. In contrast, in the infants in Group 2, the P₅₀ immediately after exchange transfusion had risen to 23.1, was 25.9 at 24 hours, and was 28.1 five days after exchange. The 2,3-diphosphoglycerate values at these times averaged 3.5, 4.9, and 6.5 mmoles per milliliter of red blood cells. These studies illustrate that while blood less than 5 days of age is generally considered to be suitable for exchange transfusions, considerable differences exist between blood of one and 5 days of age with respect to oxygen affinity. It is suggested that only truly fresh blood be employed for exchange transfusion in any severely ill infant.