Diffusion of Oxygen in Plasma and Blood

Abstract

Quantitative analysis of oxygen transport in blood requires accurate values for the oxygen diffusion coefficient (D) in blood plasma and in whole blood. There has been a controversy over the effect of plasma composition on D. One group [1] has found a precipitous drop in plasma D with small changes in the concentrations of various common plasma proteins. This would have profound physiological and pathological consequences [2,3]. Other groups [4,5,6] have found D in solutions of plasma proteins to be well-behaved, decreasing regularly with increasing protein concentration. None of these measurements, however, have been made on natural human plasma. The present study, which used freshly drawn human plasma, found that D decreased almost linearly with total protein content, even in very abnormal plasmas. It also found that the D in plasma and its serum were identical and that serum could be stored frozen for several months without changing its D. From measurements of D in plasma, and literature values for D in packed red blood cells, D in whole blood was estimated.