A modified Casson equation to characterize blood rheology for hypertension

Abstract

A modified Casson equation was established, verified satisficatorily for real conditions and suggested for use in clinical hemorheology. It provides 5 Casson parameters, i.e., Casson yield stress, Casson viscosity, the first critical point of shear rate to cause rouleaux to be broken down into smaller units, the second critical point of shear rate to completely disaggregate into individual erythrocytes, the difference between the two critical points, and also gives two series of the 5 above‐mentioned Casson parameters, respectively, under original hematocrit and the standardized hematocrit of 45%. This equation not only reveals the apparent abnormalities of hypertensive patients and normalities of the healthy persons, but also reveals hidden abnormalities for patients with either low or high hematocrit. For 20 cases of hypertensive patients with low hematocrit, the 5 Casson parameters have lower values than control, but the modified equation reveals their hidden higher values than control when their hematocrit is standardized to 45%. For 7 cases of polycythemia complicated with hypertension, the 5 Casson parameters are higher at their original hematocrit, and the modified equation reveals the higher parameters than control also when the hematocrit is standardized to 45%. For 8 cases of polycythemia without complications, the 5 Casson parameters are higher at their original hematocrit than control, while the modified equation still reveals their normalities when standardizing their hematocrit to 45%.