Influence of route of administration on hemodynamic effects of endotoxin

¹ Department of Applied Immunology, Walter Reed Army Institute of Research, Washington, D. C.

The effect of route of administration of endotoxin upon subsequent hemodynamic events was evaluated in a perfused canine small intestinal preparation. One ld₅₀ of Shigella flexneri endotoxin was injected into either the superior mesenteric artery (6 animals), a mesenteric vein (6 animals), or the right femoral vein (6 animals). Pressures were monitored in the superior mesenteric artery, a mesenteric vein, and the left femoral artery for 30 min after injection of endotoxin. In the three groups of dogs the same qualitative effects were observed: portal venous hypertension, systemic arterial hypotension, and an increase in small intestinal vascular resistance. However, portal hypertension was greatest when endotoxin was injected into the portal circulation, systemic arterial hypotension was most profound when endotoxin was injected into a femoral vein, and mesenteric vascular resistance was most prolonged when endotoxin was injected into the mesenteric artery. These findings suggest that the hemodynamic response of a regional vascular bed to endotoxin is influenced by the initial plasma concentration of lipopolysaccharide.

Key Words: endotoxin shock • Shigella flexneri endotoxin • gram-negative septicemia • experimental endotoxemia • peripheral vascular collapse

Submitted on April 25, 1963