THE CIRCULATING RED CELL AND PLASMA VOLUME AND THE DISTRIBUTION OF BLOOD IN LARGE AND MINUTE VESSELS IN EXPERIMENTAL SHOCK IN DOGS, MEASURED BY RADIOACTIVE ISOTOPES OF IRON AND IODINE1

During World War I a recently developed dye method of measuring plasma volume (1) was em-ployed, to a limited extent, in the investigation of hemorrhagic and traumatic shock in wounded soldiers. Those studies (2 to 4) showed that shock was associated with varying degrees of re-duction in the measurable total blood volume. It was assumed that this reduction resulted in a de-creased venous return to the heart, which ac-counted for diminished blood flow and death in vascular collapse. It was also felt that severity of shock as judged clinically was proportional to the degree of blood volume reduction. Cannon (5) summarized the results of these investigations in 1923. There was little change in this concep-tion of the fundamentals of shock for several years, and, as might be expected, little improvement in the therapy of shock. Blalock(6) concluded that the decrease in blood pressure in experimental traumatic shock was due to loss of blood into damaged areas, or to hemorrhage into the intestinal tract (7). Moon (8) on the basis of pathological observations on dogs dying in prolonged shock (peritonitis) con-cluded that increase in capillary permeability per-mitting the leakage of plasma from the vascular bed was chiefly responsible for loss in blood vol-ume. IThe work described in this paper was done under contracts recommended by the Committee on Medica