Besides many of the problems seen with adult transfusion, in neonates there are additional difficulties related to the small blood volume of the infant, the immaturity of the immune system and some of the enzyme systems, and the relatively high hematocrit level of the newborn. On the positive side, up to age 4 months the infant rarely forms alloantibodies against red cell antigens. It has been reported that the most common need for transfusion is to correct anemia due to blood drawn for laboratory tests. The hematocrit level of transfused blood to correct anemia must be adjusted to approximately 65%. Generally, aliquots of 20-60 ml are prepared from single-donor units. If the donor blood has been stored and contains additives, it may be necessary to wash the RBCs in order to remove some of the additives, especially in premature or seriously ill infants. Although transfusion criteria vary, one published guideline advocates transfusion to maintain the hematocrit level at 40% in newborns or in neonates on ventilators or needing oxygen support. Transfusion also would be considered if more than 10% of the infant’s blood volume were withdrawn for laboratory tests within a 10-day period.

Exchange transfusion at one time was commonly performed for HDN, but with the use of phototherapy the need for exchange transfusion is uncommon. Some have used exchange transfusion in occasional patients with sepsis or disseminated intravascular coagulation and in premature infants with severe respiratory distress syndrome. If the mother and infant have the same ABO group, group-specific RBCs are used. If the ABO groups are different, group O cells are used. If the infant is Rh positive, Rh positive blood can be used unless an anti-D antibody is present; in this case, Rh negative blood is necessary. The mother’s serum is generally used to crossmatch the donor. Donor blood less than 1 week old in CPDA-1 anticoagulant is most frequently used. It is considered desirable that the blood not have cytomegalovirus antibodies or hemoglobin S. A donor blood hematocrit level of 40%-50% is preferred and can be adjusted in several ways. If the newborn develops polycythemia (hematocrit level of 65% or more during the first week of life), partial exchange transfusion with replacement by crystalloids or 5% albumin would be necessary in order to lower the hematocrit to a safer level of 55%-60%.

Platelet transfusions may have to be given for bleeding due to thrombocytopenia of DIC, infection, or antiplatelet antibodies. Antiplatelet antibodies may be due to maternal idiopathic thrombocytopenic purpura (ITP) or due to maternal sensitization and antibody production from a fetal platelet antigen that the mother lacks (most commonly P1A1). In these cases, IV immune globulin (IVIG) may be helpful as well as platelet transfusion. However, there are conflicting reports on whether IVIG has a significant beneficial effect.