Intracellular Fluid Loss in Hemorrhage.

Following a sublethal loss of blood an immediate inflow of fluid into the capillary bed takes place. This fact has been repeatedly demonstrated by measurements of reduction in the concentration of plasma protein, fall in specific gravity of the plasma (1), and diminution in dry residue of serum (2). There seems to be no clear evidence regarding the sources of the fluid by which plasma volume is restored after hemorrhage, the usual statement merely implicating " the tissues." On the other hand, the importance of the splenic reservoir as a source of formed elements after loss of blood is well known. Attempts to obtain information on this subject by tissue analyses following hemorrhage have on the whole been inconclusive (3), owing to technical difficulties, variation in composition of different tissues, and the small changes to be expected when the volume of blood lost is considered in relation to the body mass. In one of the first careful studies of base metabolism Gamble introduced the principle, now widely accepted, of the parallel movement of base and water in the body (4). Since potassium is the chief base in cell fluid and since the concentration of potassium outside cells is kept rigorously low, by measuring the amount of potassium excreted from the body above the intake and above that liberated by protoplasmic breakdown a measurement of the extent of fluid lost from cells by diffusion is obtained. By using this principle Butler, McKhann and Gamble were able to compute the loss of intracellular fluid in diarrheal disease of infants (5). The present study was directed at determining whether the fluid which supports plasma volume under the exigencies of hemorrhage is entirely of extracellular origin, or whether intracellular fluid as well is drawn into the circulating blood.