Blood Volume in Experimental Endotoxic and Hemorrhagic Shock

Studies in Acute Iron Poisoning III. The Hemodynamic Alterations in Acute Experimental Iron Poisoning

“…Peripheral resistance units (PRU) = mean arterial BP (mm Hg) cardiac output (ml/s) Plasma volume and red cell mass were determined simultaneously and independently by a double-labeling radioisotope dilution technique [2]. Plasma volume was determined by injecting 1 ml of human serum albumin labeled with 2.0 microcuries of I 125 .…”

“…The only published data on changes of blood volume were obtained during the course of three nonlethal poisonings [7], Several investigators have indicated that blood volume studies in dogs are reliable only when red cell mass and plasma volume are measured simultaneously and independently [1,2,4]. GRABLE et al [2] utilized this type of monitoring in a study of hemorrhagic and endotoxic shock and did not find a significant preterminal deficit in total blood volume (mean 7 %). Through the use of this technique, the preterminal deficit in total blood volume in our 10 dogs with acute iron poisoning averaged 30 %.…”

“…The deficit was primarily the result of a decrease in plasma volume. The mechanism responsible for the reduction in plasma volume in hemorrhagic and endotoxic shock is assumed to be a loss of plasma due to increased intracapillary pressure (capillary stasis) [2]. The magnitude of the change in plasma volume found in dogs with iron poisoning was considerably greater than the loss associated with capillary stasis [2] and suggests the presence of increased capillary permeability unrelated to pressure changes.…”

“…The mechanism responsible for the reduction in plasma volume in hemorrhagic and endotoxic shock is assumed to be a loss of plasma due to increased intracapillary pressure (capillary stasis) [2]. The magnitude of the change in plasma volume found in dogs with iron poisoning was considerably greater than the loss associated with capillary stasis [2] and suggests the presence of increased capillary permeability unrelated to pressure changes. Elevated levels of vasoactive substances (serotonin and histamine) in plasma have been detected during acute experimental iron poisoning [11] and these substances could produce an increase in capillary permeability.…”

Changes in Forelimb Weight and Segmental Vascular Resistances Following Severe Hemorrhage

“…Plasma volume measured with dilution techniques fails to decrease in splenectomized dogs and primates (monkeys) subjected to circulatory shock, and hematocrit fails to increase relative to control (16)(17)(18)(19)(20)(21). Other investigators (16,19,(22)(23)(24) employing these same techniques have failed to find evidence for significant transvascular fluid efflux in dogs (intact spleens) subjected to shock, i.e., the magnitude of the measured decrease in plasma volume was small. In man, the available data, although sparse and fragmentary, fail to provide evidence for fluid filtration in circulatory shock (15,25,26).…”