Experiments were designed to find the volume of blood loss or arterial pressure necessary to produce a significant difference between the measured and expected cell and plasma volume after hemorrhage and following reinfusion. Anesthetized dogs were divided into three groups: The first group was bled a mean of 16% of the original blood volume; the second and third groups were bled to 50 mm Hg (mean bleeding volume of 26%) and 35 mm Hg (mean bleeding volume of 49%) arterial pressure respectively. Red cell volume was measured using radioactive Cr51 and plasma volume with radioactive I131. There was agreement between the expected and measured cell and plasma volume in dogs bled 16 and 26% (held at 50 mm Hg pressure) of their initial blood volume and after reinfusion of the blood. However, the standard error for the 26% group was large. The measured and expected cell and plasma volume of dogs bled 49% (held at 35 mm Hg pressure) of their initial blood volume was not in agreement either after the hemorrhage or reinfusion. A blood pressure of 50 mm Hg appears to be a critical pressure for the operation of the compensatory mechanisms involved in the release of fluid into the circulation, and for the trapping of red cells.
No takes yet. Share an insight, caveat, or question.
Deavers et al. (1958) studied this question.