Transfusionsgrenzen – Restrictive Liberal Transfusion Thresholds: When should extremely preterm infants receive blood transfusions?

Transfusions are frequently administered to extremely preterm infants and 50–80% of these infants will receive multiple transfusions during their initial hospitalization. Despite being a universally accepted part of the treatment of preterm infants, RBCT practices vary greatly between neonatal units in the absence of uniformly accepted physiologic or evidence-based transfusion criteria. The short-term effects of transfusion on outcome measures such as apnea, weight gain, heart rate, and oxygen consumption have been studied in a few small randomized, mostly uncontrolled trials and several observational studies with controversial results – conclusive data of long-term effects of transfusion practices do not exist. Reducing the number of transfusions will reduce the risk of transmission of Cytomegalo, Hepatitis, Human Immune Deficiency Viruses, and other infectious agents and may reduce costs. Since frequent transfusion may be associated with retinopathy of prematurity and bronchopulmonary dysplasia, reducing transfusion may be even more important. It has been shown, that 'restrictive' transfusion guidelines effectively reduce the number of transfusion administered to preterm infants. However, reducing transfusion by accepting low hemoglobin concentrations carries the risk of at least temporarily insufficient oxygen transport to vital organs, especially the brain, and ultimatively of impaired long-term outcome. There is no evidence that achieving a reduction in transfusion by accepting 'restrictive' transfusion guidelines (i.e., by accepting very low hemoglobin levels) is safe and ultimately benefits the patient. In conclusion, there is insufficient evidence to decide whether preterm infants should be treated according to liberal or restrictive transfusion guidelines. The long-term safety and efficacy of 'restrictive' and of 'liberal' transfusion practices need to be evaluated in an adequately powered, large, randomized, controlled trial with long-term neuro-developmental follow-up and with a sufficient difference in mean hemoglobin levels between both treatment arms to reflect the range of transfusion guidelines currently applied.