Hemodynamic Alterations in the Anesthetized Pony Produced by Slow Intravenous Administration of Escherichia coli Endotoxin

SUMMARY Escherichia coli lipopolysaccharide endotoxin was administered to 9 anesthetized Shetland ponies to determine the hemodynamic response. The endotoxin was slowly infused intravenously for a 1-hour period. The response was characterized by an early abrupt transitory arterial hypotension and central venous, right ventricular, and pulmonary arterial hypertension. The early changes were followed by a period of gradual prolonged systemic arterial hypotension and normal right heart pressures. The classic signs of shock, cold extremities and respiratory abnormalities were evident in all ponies given endotoxin.