Role of the non-Newtonian behavior of blood in hemodynamics

Abstract

The role of the non-Newtonian behavior of blood in perfused vascular beds has been assessed by measuring the pressure-flow curves of erythrocyte suspensions with hematocrits from 9 to 85%, in glass tubes of radii from 50 to 800 µ. The curves become linear as the flow increases, and for each tube, point back to a ‘nodal point’ on the negative flow axis which is independent of hematocrit. From this data, curves of the rate of shear versus shearing stress at the wall (consistency curves) were obtained which are all linear at stresses greater than 20 dynes/cm. The wall shearing stress in all categories of blood vessels is greater than this, especially in the arterioles where it is 200 dynes/cm. It is concluded that in perfused vascular beds the flow properties of blood are essentially linear in the physiological working range so that the distensibility of the vessels is the all important factor in determining the shape of the pressure-flow curves.

Pressure-flow relationship of erythrocyte suspension in perfusion of Nuclepore membrane and red cell deformability.

“…The asymptotic lines (extrapolated linear segments) of P-Q curves in a glass tube converge to the same point on the negative 0-axis (Fig. 3A), and similar results have been reported in the perfusion of a glass tube (HAYNES and BURTON, 1959) and in the perfusion of a bullfrog's hind limb (INOUYE et al, 1976). On the other hand, the asymptotic lines of P-Q curves in NP membrane do not meet at a single point on the negative Q-axis (Figs.…”

“…3A). It can be concluded that the increase in the value of the negative intercept in the perfusion of NP membrane indicates clearly an obstruction or plugging of the pores by erythrocytes, taking theoretical and experimental results in the perfusion of a rigid glass tube (GORDON,1970;HAYNES and BURTON, 1959) and of a bullfrog's hind limb (INOUYE et al, 1976) into account. It is suggested also that the non-linear part of the P-Q relationships of erythrocyte suspensions in the perfusion of NP membrane is due mainly to non-Newtonian properties of suspension and partly to the obstructive procedure of erythrocytes during passage through a membrane.…”

“…The asymptotic lines (extrapolated linear segments) of all P-Q curves converged to the same point on the negative a-axis, that is, the intercept of a-axis was independent of Hct value. It has been widely accepted that the non-linear segment of these curves for erythrocyte suspension originated from non-Newtonian properties of the suspension (HAYNES and BURTON, 1959;CORDON, 1970). Since all asymptotic lines met at a single point on the negative Qaxis, the decrease in rate of flow at high P corresponded quantitatively to the increase in a reciprocal of a slope of the asymptotic line, namely, increase in the resistance to flow according to Poiseuille's law (PAPPENHEIMER and MASS, 1942).…”

“…Since all asymptotic lines met at a single point on the negative Qaxis, the decrease in rate of flow at high P corresponded quantitatively to the increase in a reciprocal of a slope of the asymptotic line, namely, increase in the resistance to flow according to Poiseuille's law (PAPPENHEIMER and MASS, 1942). Furthermore, assuming that the viscosity of NaCI solution was 1 cP at 22°C, relative apparent viscosity of different erythrocyte suspension was obtained from a slope of the P-Q relationship (HAYNES and BURTON, 1959). Thus the resistance to flow and the relative apparent viscosity can be an exponent of the flow rate in the perfusion of a rigid glass tube.…”

Rheology of Human Blood. Studies on the Flow of Fresh Venous Blood and of Citrated Blood Through Tubing of Diameters Between 0.09 and 0.20 Cm

“…Numerous studies have demonstrated that the rheological properties of blood are anomalous, in particular, that rate of flow through cylindrical tubing is not related linearly to the imposed gradient in pressure and that the viscosity of blood increases at low rates of flow (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). These data, and similar data obtained by means of other viscometric methods (11)(12)(13), are characteristic of non-Newtonian flow (14) and necessitate that any study of the rheological properties of blood must examine the dependence of viscosity upon applied shearing stress.…”