Partial exchange transfusion to prevent neurodevelopmental disability in infants with polycythemia.

Hyperviscosity of blood results in increased resistance to blood flow and decreased oxygen delivery. In the neonate, hyperviscosity can cause abnormalities of central nervous system function, hypoglycemia, decreased renal function, cardiorespiratory distress, and coagulation disorders. Hyperviscosity has been reported to be associated with long-term motor and cognitive neurodevelopmental disorders. Blood viscosity exponentially increases when an infant has polycythemia (hematocrit >/= 65%). Partial exchange transfusion (PET) is traditionally used as the method to lower the hematocrit and treat hyperviscosity.