Neonatal anemia and red blood cell transfusions: finding the optimal balance

Neonatal anemia is common in preterm infants admitted to the neonatal intensive care unit (NICU). In newborn infants with perinatal asphyxia it can be severe. The red blood cell (RBC) transfusion is an effective intervention aiming to rapidly improve oxygen transport to vital organs. Noteworthy, there are also complications. Besides risks of transfusion reactions, RBC transfusions are associated with an increased risk of several morbidities. The lack of knowledge on the balance of benefits and risks of RBC transfusions for anemic infants, has led to controversies about the optimal threshold and the best moment to transfuse these high-risk infants. The primary aim of this thesis was, therefore, to clarify controversial issues regarding neonatal anemia and RBC transfusions, specifically regarding the effects of anemic hypoxia on the one hand, and adverse effects of RBC transfusions on the other. The studies reported in this thesis provide insight into the short-term effects of both neonatal anemia and RBC transfusions on the brain and the intestine of preterm infants. Furthermore, this thesis provides evidence for an improved neurological outcome when using a lower limit of cerebral oxygen saturation to guide RBC transfusions in anemic preterm infants, rather than a threshold solely based on hemoglobin level. Finally, this thesis addressed the influence of perinatal anemia on outcomes in term infants with neonatal encephalopathy. The results of this thesis may therefore contribute to individualizing and improving NICU treatment for these vulnerable infants regarding anemia and RBC transfusions