Cardiovascular and Metabolic Effects of Whole or Fractionated Gram-Negative Bacterial Endotoxin in the Unanesthetized Rhesus Monkey

Rhesus monkeys were infused with endotoxin lipopolysaccharide (LPS) (10 mg/kg [LPS10] or 2.5 mg/kg [LPS2.5]) or with fractions of LPS containing 6.3% lipid (PS1) or 0.5% lipid (PS2) (2.5 mg/kg). Systemic and regional hemodynamics, leukocyte counts, blood gases, pH, and plasma bradykinin concentration were measured. Monkeys receiving LPS10, LPS2.5, or PS1 became hypotensive (mean blood pressure -37 ± 10 mm Hg) and had decreased peripheral vascular resistance (-10% to -24% of the base line), compensated metabolic acidosis, and elevated plasma bradykinin concentrations (14 ± 6 ng/ml) 2 hours after infusion. Vasodilation occurred in coronary, hepatic, and splanchnic vasculature; vasoconstriction occurred in the spleen. Cardiac output was diverted from muscle to viscera. Monkeys receiving PS2 were normotensive with elevated peripheral vascular resistance (+46%) and no measurable plasma bradykinin concentration. By 6 hours, marked elevation of peripheral vascular resistance developed in monkeys given LPS10 (+11...