Effects of slow intravenous endotoxin infusion on hemodynamics and survival in dogs.

Abstract

Experiments were carried out to compare the effects of slow intravenous endotoxin infusion with rapid endotoxin injection on hemodynamics and mortality in 44 dogs anesthetized with Nembutal. Arterial blood pressure (Pa) of dogs infused with endotoxin usually decreased gradually after starting the infusion while Pa of dogs injected with endotoxin usually fell immediately and precipitously to low levels. However, after approximately 30 min, Pa''s of surviving animals of both groups were not greatly different. Changes of portal vein pressure, heart rate, pH, and hematocrit were not consistently different in either group. The number of dogs surviving at 12-24 hr after endotoxin was considerably greater in the group receiving endotoxin as a slow infusion. Beyond this time, mortality was not greatly different. These data show that it might be advantageous to infuse endotoxin slowly in some experimental models in order to avoid early severe changes of Pa and early deaths.