Physiopathologic responses of the rhesus monkey to live Escherichia coli

This study was designed to develop an animal model applicable to the clinical patient in the investigation of the pathogenesis of septic shock. The model currently described is a lightly anesthetized, unrestrained monkey, carefully monitored during a 24 hr observation period. Varying doses of live Escherichia coli organisms were infused i.v. during a 30 min period, and a variety of hemodynamic, respiratory and metabolic parameters were monitored. Doses of organisms varied between 7.6X10 ⁹ and 3.0x10 ¹¹ organisms per kilogram of body weight, and there was no obvious correlation between size of dose and survival time. Two of 9 male experimental monkeys survived the Escherichia coli, while times of death of the remaining monkeys varied between 3 and 27 hr. Two control monkeys, not administered organisms, survived the 24 hr period with minimal changes in all measured parameters. Results reveal 2 patterns in response to organism administration. These were early acute death, after 3 to 4 hr, and prolonged life, death after 20 to 27 hr. The acute response was characterized by marked systemic hypotension, hypoglycemia, hypoinsulinemia, increased lactate level, decreased pH or respiratory depression. The other type of response involved profound sustained hypotension with hypoglycemia and hypoinsulinemia in most monkeys and elevations in lactate, blood urea nitrogen, potassium creatinine, serum glutamicoxalacetic, lactic dehydrogenase and fractionated lactic dehydrogenase levels. Depressions in respiration were not evident in the group which survived a longer period of time. Renal fibrin thrombi, prominent in baboons administered Escherichia coli, were absent in the rhesus monkey regardless of the size of the dose or organisms. The results of this study suggest the operation of a multifactorial mechanism in septic shock with interactions between hemodynamic and metabolic factors varying within the species.