The aim of treatment is to prevent bilirubin neurotoxicity.
Indications for immediate exchange transfusion:
— The cord blood hemoglobin level is significantly less than normal (perhaps a threshold of ≤110 g/L).
— The bilirubin level is greater than 4.5 mg/dL.
— Cord blood bilirubin is rising rapidly (> 0.5 mg/dL per hour).
If the infant is premature or has unstable vital signs, less stringent criteria are used to give an exchange transfusion. After the first exchange, the rate of rise of bilirubin is used to guide to subsequent transfusions.
Double volume exchanges will remove, perhaps, 85 percent of sensitized red cells and greater than 50 percent of intravascular bilirubin, and also some maternal anti-D antibody.
In some centers, prior to exchange, intravenous albumin is given to mobilize extravascular, interstitial bilirubin. Removal of sensitized red cells and prevention of bilirubin formation is the most efficient approach.
ABO-compatible, RhD-negative, irradiated blood is used, cross-matched against the mother.
Potential newborn complications of exchange transfusion include hypocalcemia, hypoglycemia, thrombocytopenia, dilutional coagulopathy, neutropenia, disseminated intravascular coagulation, umbilical venous or arterial thrombosis, enterocolitis, and infection. Permanent serious sequelae or neonatal death has been reported in a rate as high as 12 percent in sick infants compared to <1 percent in healthy infants over a period of observation from 1981 to 1995.
Recombinant human erythropoietin, 200 U/kg, subcutaneously, three times per week for 6 weeks, has been used to enhance recovery of the hemoglobin concentration and decrease the need for postnatal exchange transfusions. It is also useful in Kell antigen-mediated alloimmune disease, since in that case, erythroid hypoplasia is an important factor.
Phototherapy is used prophylactically in any patient with moderate or severe hemolysis or in infants with bilirubin levels rising at >0.5 mg/dL per hour and is the mainstay of treatment for unconjugated hyperbilirubinemia. The object is to prevent bilirubin neurotoxicity.
Intensive phototherapy (≥30 microWatts/cm2) in the 430–490 nm band delivered to as much of the infants surface area as possible.
In full-term infants (at least 38 weeks gestation) with alloimmune hemolytic disease, intensive phototherapy should be instituted if total serum bilirubin is ≥5.0 mg/dL at birth, ≥10 mg/dL at 24 hours after birth, or ≥13 mg/dL 48 to 72 hours after birth.
Phototherapy is recommended at lower bilirubin levels for preterm or ill infants or infants with a positive direct antiglobulin test, often at serum bilirubin less than 5.0 mg/dL to lessen the need for exchange transfusions.
Other treatments have been applied. For example, administration of high-dose intravenous immunoglobulin as soon as possible after diagnosis of alloimmune hemolysis is made, decreases the need for phototherapy or exchange transfusion by nonspecific blockade of macrophage Fc receptors and, thereby, a decrease in hemolysis.
Perinatal survival is greater than 90 percent with intrauterine transfusions in non-hydropic fetuses with severe alloimmune hemolytic disease. The overall survival for hydropic fetuses is approximately 85 percent despite intrauterine transfusion.
A first trimester screening program increased survival in Kell antigen induced alloimmune hemolytic disease from 61 to 100 percent in the Netherlands.