30: Exchange Transfusion

I. INDICATIONS

1. Hyperbilirubinemia. Exchange transfusion (ET) is most commonly done for infants with hyperbilirubinemia of any origin when the serum bilirubin level reaches or exceeds a level that puts the infant at risk for central nervous system toxicity (see Chapters 58 and 100). Serum levels of bilirubin for which to begin an ET are under considerable debate. Double-volume ETs taking 50–70 minutes are used for removal and reduction of serum bilirubin. Efficiency of bilirubin removal is increased in slower paced exchanges to allow for time of extravascular and intravascular bilirubin equilibration.

2. Hemolytic disease of the newborn. Results from destruction of fetal red blood cells (RBCs) by passively acquired maternal antibodies. ET aids in removing antibody-coated RBCs and replaces them with uncoated donor RBCs that lack sensitizing antigen, thereby prolonging intravascular RBC survival. It also reduces a potentially toxic bilirubin concentration, the result of the antibody destruction of RBCs. Intravenous immunoglobulin (IVIG) is now used to reduce the need for ET in hemolytic disease of the newborn. American Academy of Pediatrics guidelines recommend IVIG if the total serum bilirubin (TSB) is rising despite intensive phototherapy or the TSB level is within 2–3 mg/dL of the exchange level.

3. Sepsis. May be associated with shock caused by bacterial endotoxins. ET may help remove bacteria, toxins, fibrin split products, and accumulated lactic acid. It may also provide immunoglobulins, complement, and coagulating factors.

4. Disseminated intravascular coagulation (DIC). ET may provide necessary coagulation factors and help reduce the underlying cause of the abnormal coagulation. Repletion of clotting factors by transfusion of fresh-frozen plasma (10–15 mL/kg) may be all that is necessary in less severe cases of DIC.

5. Metabolic disorders causing severe acidosis. Partial exchanges are usually acceptable and beneficial; however, peritoneal dialysis may also be needed to treat severely acidotic disorders of metabolism.

6. Severe fluid or electrolyte imbalance. Isovolumetric partial exchanges can be used to modulate electrolyte fluctuations with each aliquot of blood exchanged. The process allows for a gradual correction of electrolyte imbalances.

7. Polycythemia. This can be managed by partial ET using normal saline. Normal saline is preferred because it reduces both the polycythemia and the hyperviscosity of the infant's circulating blood volume. (See also Chapter 71 and 122.)

8. Severe anemia. Normovolemic or hypervolemic anemia causing cardiac failure, as in hydrops fetalis, is best treated with a partial ET using packed RBCs.

9. Any disorder requiring complement, opsonins, or gamma globulin. Infants with these conditions may require frequent exchanges, and their fluid status must be carefully managed. Partial exchanges are recommended.

II. TYPES OF EXCHANGE TRANSFUSIONS

1. Single-volume exchange blood transfusion. Refers to 1 times the estimated blood volume at ∽60% of infant's blood volume.

2. Double-volume exchange blood transfusion. Refers to 2 times the estimated blood volume at ∽85% of infant's blood volume. This is indicated for severe hyperbilirubinemia (to remove bilirubin), for alloimmune hemolytic disease of newborns, to remove antibodies and abnormal proteins, and for idiopathic severe hypermagnesemia, ...