Concentration of Serum Protein Following a Singale Severe Hemorrhage in the Fasting Dog

Abstract

Numerous observations have been made on the fall in serum protein immediately following hemorrhage (particularly plasmapheresis), and its subsequent rise. According to one view, this rise is ascribed to regeneration of new serum protein, presumably from amino-acids which were absorbed from the intestinal tract or mobilized from various tissues, notably the liver and muscle. According to another view, the rise of serum protein is due to the direct entrance of protein from a “body store”. This “body store” is apparently different from that contained in the various tissue fluids and lymph which furnish a ready source of fluid, but contain only 1% of protein, which is but one-seventh of its concentration in normal blood plasma.

There is general agreement regarding the fall in serum protein which follows a severe hemorrhage. Accompanied as it is by a fall in the red cell count, the process is obviously one of dilution whereby the fluid stores of the body, poor in protein, enter the blood stream in the attempt to restore blood volume back to normal. Once this dilution has occurred, further increases in serum protein concentration are presumably due to the regeneration of new protein or the direct entrance of new protein from some immediately available source, as mentioned above. However, no inferences regarding the concentration of serum protein should overlook the influence of changes in plasma volume, which occur particularly after severe hemorrhage. Such blood volume changes are due to the fact that the vasomotor system is especially active after severe hemorrhage, resulting in rapid, and often marked, changes in the size of the blood bed. Thus, actual protein may enter the blood stream and yet be masked as far as its concentration is concerned by a coincident vasodilation; conversely, a vasoconstriction may diminish blood volume and result in an increase in the concentration of serum protein, which, in fact, is unchanged as far as the total amount circulating in the plasma is concerned.