Importance of protein content in the edema fluid for the resolution of brain edema

This study shows that there is a quantitative relation between the protein content of edema fluid and the rate of fluid clearance. Minimal clearance takes place during the first 3 days in the high albumin group. Thereafter, the majority of the fluid is cleared, and tissue water returns to normal values by 8 days. This appears to support an idea that the rate of clearance is in direct proportion to protein concentration. This also supports the findings of Kuroiwa et al. who showed a direct relation between protein extravasation and the increase of water in extracellular vasogenic edema. However, the rate of clearance does not in fact appear to be linear with time as the greater percentage of protein edema fluid is cleared after 3 days. This may be explained by the observations of Rasmussen and Klatzo and Bodsch and Hossmann who indicate that the composition of the extracellular protein may undergo various changes, similar to fragmentation, hence increasing the number of osmotically active particles so the pre-existing edema would remain stable or slightly increase. In conclusion, this study demonstrates that the infusion model of edema can be applied to the rat for study of resolution dynamics. We have also shown that in this model, there is a proportional relation between protein concentration of the edema fluid and time necessary for clearance.