Posttransfusion 24-hour recovery and subsequent survival of allogeneic red blood cells in the bloodstream of newborn infants

BACKGROUND: The feasibility, efficacy, and safety of transfusing stored allogeneic RBCs has been demon‐strated for small‐volume transfusions given to infants. We measured the posttransfusion recovery and intravascular survival of allogeneic RBCs stored up to 42 days to further elucidate their efficacy. STUDY DESIGN AND METHODS: Preterm infants were transfused with 1.0 mL of biotinylated RBCs plus 15 mL per kg of unlabeled allogeneic RBCs. Posttran‐sfusion infant blood samples obtained at 10 minutes, and at 1, 2, 4, 7, 10, 14, and 21 days were used to determine the 24‐hour posttransfusion recovery (PTR24), mean potential life span (MPL), and time to disappearance of 50 percent of biotinylated RBCs (T50). RESULTS: No significant differences were found between allogeneic RBCs stored 1 to 21 days versus 22 to 42 days for PTR24, MPL, or T50, indicating comparable posttransfusion circulation, regardless of storage age. Although MPL and T50 values in infants using biotinylated RBCs were short, compared to those expected using chromium‐labeled RBCs in adults, they agreed with results reported by others using biotinylated RBCs. CONCLUSIONS: Satisfactory posttransfusion RBC recovery and survival, measured with biotinylated RBCs, support earlier clinical trials that established the efficacy and safety of stored allogeneic RBCs for small‐volume transfusions given to infants. The relatively short MPL and T50 values in some infants may underestimate true survival due to ongoing erythropoiesis and infant growth with commensurate increase in blood volume during the time of RBC survival studies. Because values in infants differ from those expected using chromium‐labeled RBCs in adults, and the number of posttransfusion determinations was few, additional studies are needed to define the mechanisms involved.