DIFFUSION-COEFFICIENTS AND SOLUBILITY COEFFICIENTS FOR GASES IN BIOLOGICAL-FLUIDS AND TISSUES - A REVIEW

Based on a review of 166 references for diffusion and solubility coeff icients in biological fluids and tissues, we have tabulated experiment al values for the gases Ar, CO2, H-2, He, N-2, Ne, N2O, O-2, and SF6. Two major conclusions can be drawn: a) for tissues, there is a scarcit y of available data; and b) in general, there are significant differen ces between Values determined by different investigators, the discrepa ncies being most prominent for diffusion coefficients. For water, we g ive numeric Values of the temperature coefficients and preferred diffu sion and solubility coefficients at 25 degrees and 37 degrees C. Furth er, we describe several methods for estimation of coefficients where e xperimental data are lacking. For tissues, none of the formulas descri bed give precise predictions for all gases, but rough estimates suffic ient for most qualitative work can almost always be found. In particul ar, the data material indicates that for all tissues other than far, t issues consisting of mainly triacylglycerols, the solubility coefficie nts for water may be used as a good approximation. Except for SF6, the error in this approximation probably does not exceed 20%. In contrast , diffusion coefficients for most tissues are from 25 to 50% lower tha n the respective coefficients in water, generally increasing with the water content of the tissue.