Effect of Pneumococcus SIII Polysaccharide on Viscosity and Heat Transfer of Human Blood

Abstract

Conclusions

The resistance of blood flow to cardiac effort in health and disease depends, in part, on the viscosity of blood, a non-Newtonian system. Measurements of viscosity of such systems are open to question. Measurement of the viscosity of blood, particularly in infectious diseases, presents still more problems due to the varying aggregation of blood cells sometimes referred to as "sludging." These aggregates are often broken up, in part at least, as blood is forced through small capillary tubes in vitro.

In an effort to obtain a measurement which might be related to viscosity, heat transfer of blood in a static situation was examined. No correlation was obtained between heat transfer of blood with all concentrations of the added pneumococcus SIII polysaccharide, and the time required to pass through an Ostwald viscosimeter. A decrease in heat transfer was noted with addition of 0.025% SIII but more of the polysaccharide did not decrease heat transfer although such additions greatly increased the time required to pass through the Ostwald apparatus. Therefore, heat transfer of blood-pneumococcus SIII systems and viscosity as measured by the Ostwald technique must be considered as probably dependent on other properties of blood not yet definable.

In contrast, a good correlation was obtained, as would be expected, between heat transfer and viscosity of varying concentrations of glycerol in water, a Newtonian system, as measured by the Ostwald viscosimeter.

It is hoped that this report may stimulate those qualified to design more sophisticated methods in the area of the rheology of blood to clarify the relationship between heat transfer and viscosity of non-Newtonian systems. Inasmuch as heat transfer from internal organs to the skin or lungs represents an important physiological mechanism in itself, such measurements assume independent significance.