Equilibrium behavior of tagged erythrocytes in experimental “irreversible shock”

Summary o 1. Equilibrium behavior of erythrocytes tagged with Evans blue dye and radiochromate in the normal and shocked animal was studied. 2. There was no alteration in the disappearance curve of Evans blue dye. 3. There seemed to be a slope of decreasing erythrocyte activity in the shocked animals. This slope was not such as to produce a statistically significant decrement at either 50 or 90 minutes. In Shoemaker's work, steep slopes of strong significance were reported in two thirds of the animals. 4. In no animal did we observe an “inflection point” with a secondary plateau to suggest the clear delineation of a “slowly circulating” red cell volume. 5. The red cell volume measured at the conclusion of the experiment correlated almost perfectly with that observed at the start, as corrected for volume loss by sampling. We therefore did not discover any evidence for a “noncirculating” red cell mass in these animals. 6. On the basis of these data, we cannot confirm the concept that irreversible shock in the dog results in a significant sequestration of erythrocytes from that mass normally exchangeable with infused tagged cells.