BLOOD-VISCOSITY PROFILES IN POLYCYTHEMIA - NEONATAL POLYCYTHEMIA

Hemorheological studies were conducted on cases of neonatal polycythem ia and cases exhibiting the neonatal hyperviscosity syndrome. It was f ound that though hematocrit is the major contributing factor towards h yperviscosity, low plasma viscosity and decreased erythrocyte deformab ility also contribute to the final picture of whole blood viscosity ob served in neonatal polycythemia. Hyperviscosity may be present in abse nce of polycythemia and may be responsible for the clinical hypervisco sity syndrome. This revealed the importance of estimation of whole blo od viscosity in cases of newborns at risk, in whom just the estimation of hematocrit may not be enough to diagnose the condition of hypervis cosity. Measurement of red cell filterability may also be important, a s reduced filterability may contribute to the increase in the whole bl ood viscosity in polycythemia or even otherwise. From this study, it c ould be seen that neonates exhibiting the hyperviscosity syndrome may not necessarily have polycythemia or for that matter may not have bloo d hyperviscosity. This makes estimation of whole and red cell deformab ility to be important parameters to exclude the diagnosis of hypervisc osity in the 'neonate so that other clinicopathological explanations m ay be sought by the attending physician to explain the symptoms and si gns.