Responses of the baboon to live Escherichia coli organisms and endotoxin

This study was designed to develop a nonhuman primate model more relevant to the clinical entity of septic shock. Experiments were conducted on young adult baboons, unrestrained and maintained at a light plane of anesthesia induced with pentobarbital sodium. Responses of baboons infused with Escherichia coli endotoxin or live Escherichia coli organisms were evaluated during a 24 hour period or until death. Results suggest significant differences between the two shock models: large dosages of endotoxin in contrast to those used in the canine species were required to elicit lethality characteristics. Hypoglycemia and hypoinsulinemia were regularly observed in live Escherichia coli organism-induced shock. However, hyperglycemia was a consistent hallmark in the endotoxin-infused model. Renal fibrin thrombi were present only after Escherichia coli administration, while tubular necrosis was found following both organism and endotoxin infusions. Renal morphologic changes, induced during shock, were prevented by the administration of heparin. Liver dysfunction was indicated by elevations of blood levels of enzymes and morphologic alterations. Pulmonary function did not appear to be abnormally affected, although respiratory alkalosis and metabolic acidosis were regularly observed in both models. Significant differences in responses between the modes should elicit caution in the application of findings in nonhuman primates to the human patient.