Changing patterns of red blood cell transfusion in very low birth weight infants

Objective: Anemia develops in increasing numbers of critically ill very low birth weight (VLBW) infants who survive the neonatal period, and they receive multiple red brood cell (RBC) transfusions. Despite their need for prolonged medical treatment, we hypothesized that VLBW infants presently receive fewer RBC transfusions as a result of the growing awareness of transfusion risks and improvement of neonatal care. Methods: RBC transfusion practices and clinical outcomes in infants with birth weights of 1.5 kg or less were analyzed retrospectively in three selected years: 1982, before awareness of the human immunodeficiency virus; 1989, before surfactant availability; and 1993, before erythropoietin approval. Results: Progressive declines in RBC transfusions, donor exposures, and transfusion volumes occurred concurrently with decreases in morbidity and mortality rates. Transfusions per infant (mean +/- SD) declined from 7.0 +/- 7.4 in 1982 to 5.0 +/- 5.8 in 1989 to 2.3 +/- 2.7 in 1993 (p <0.001). This decline was associated with a decrease in pretransfusion hematocrit (33.6% +/- 2.8% in 1982, 34.2% +/- 3.7% in 1989, and 29.8% +/- 5.1% in 1993; p <0.001). The distribution of RBC transfusions given by week of life among study years did not change; 70% of RBC transfusions were given within the first 4 weeks, when infants are sickest. Although the percentage of VLBW infants weighing more than I kg at birth and never receiving any RBC transfusions increased with time (17% in 1982, 33% in 1989, and 64% in 1993), more than 95% of infants weighing 1 kg or less in all years received transfusions. Conclusions: Overall administration of neonatal transfusions has decreased markedly, most likely because of multiple factors. Because most RBC transfusions are given to infants weighing I kg or less in the first weeks of life, therapeutic strategies should focus on this group of VLBW infants during this critical period. The temporal changes observed in transfusion patterns emphasize the importance of including concurrent controls in future studies evaluating transfusion interventions.