Blood viscosity profiles in polycythemia: Neonatal polycythemia

Abstract

Hemorheological studies were conducted on cases of neonatal polycythemia and cases exhibiting the neonatal hyperviscosity syndrome. It was found that though hematocrit is the major contributing factor towards hyperviscosity, low plasma viscosity and decreased erythrocyte deformability also contribute to the final picture of whole blood viscosity observed in neonatal polycythemia. Hyperviscosity may be present in absence of polycythemia and may be responsible for the clinical hyperviscosity syndrome. This revealed the importance of estimation of whole blood viscosity in cases of newborns at risk, in whom just the estimation of hematocrit may not be enough to diagnose the condition of hyperviscosity. Measurement of red cell filterability may also be important, as reduced filterability may contribute to the increase in the whole blood viscosity in polycythemia or even otherwise. From this study, it could be seen that neonates exhibiting the hyperviscosity syndrome may not necessarily have polycythemia or for that matter may not have blood hyperviscosity. This makes estimation of whole and red cell deformability to be important parameters to exclude the diagnosis of hyperviscosity in the neonate so that other clinicopathological explanations may be sought by the attending physician to explain the symptoms and signs.