Effects of continuous intravenous infusion of Escherichia coli endotoxin into swine.

Escherichia coli endotoxin was continuously infused IV into 31 pigs. The response was related to the infusion rate. Of 13 pigs given endotoxin at the rate of 15.4 and 23.1 micrograms/kg of body weight/hour, 10 had bilateral renal cortical necrosis similar to a generalized Shwartzman lesion. All 13 pigs given endotoxin at the rate of 6.6 to 12.1 micrograms/kg/hour survived the infusion and were euthanatized 7 to 12 days later. Most of the pigs that developed chronic neurologic disturbances were given the smaller dose of endotoxin. Of 5 pigs given endotoxin at the rate of 22.0 to 23.1 micrograms/kg/hour after receiving 200 U of sodium heparin/kg of body weight, 1 died during the 48-hour period of infusion and the 4 pigs euthanatized 8 to 12 days later had lesions that were similar to those produced by endotoxin without heparin. The 4 control pigs given continuous IV infusion of isotonic saline solution at a rate of 30 dl/hour had no clinical signs or pathologic lesions. The continuous IV infusion of endotoxin into pigs at various doses produced similar clinical signs of endotoxic shock. Pigs that died acutely had widespread thrombosis. The hematologic findings indicated an intravascular coagulopathy and some of the clinical signs and lesions in the pigs resembled changes in the CNS in pigs with spontaneous edema disease (ED); however, distinct differences were also observed. Fibrinoid vascular necrosis did not occur in the CNS, and this lesion is consistently present in naturally occurring ED. The exact nature of the causal substance or substances causing ED is still unknown, but is considered an angiotoxin associated with hemolytic E coli.