Objective: To investigate the systemic, pulmonary, and hepatosplanchnic hemodynamic and metabolic effects of delayed treatment with ethyl pyruvate in a long-term porcine model of hyperdynamic endotoxemia.
Design: Prospective, randomized, controlled experimental study with repeated measures.
Setting: Investigational animal laboratory.
Subjects: Anesthetized, mechanically ventilated, and instrumented pigs.
Interventions: After 12 hrs of continuous infusion of lipopolysaccharide and hydroxyethyl starch to keep mean arterial pressure >60 mm Hg, swine randomly received placebo (Ringer's solution; control group, n = 11) or ethyl pyruvate in lactated Ringer's solution (n = 8; 0.03 g.kg(-1) loading dose over 10 mins, thereafter 0.03 g.kg(-1)hr(-1) for 12 hrs).
Measurements and main results: Whereas mean arterial pressure significantly decreased in control animals, mean arterial pressure was maintained at the baseline level in pigs treated with ethyl pyruvate. Global oxygen uptake was comparable, so that the trend toward a higher oxygen transport and the significantly higher mixed venous hemoglobin oxygen saturation resulted in a significantly lower oxygen extraction in the ethyl pyruvate group. Ethyl pyruvate reduced intrapulmonary venous admixture and resulted in significantly greater Pa(O2)/F(IO2) ratios. Despite comparable urine production in the two groups during the first 18 hrs of endotoxemia, ethyl pyruvate significantly increased diuresis during the last 6 hrs of the study. Lipopolysaccharide-induced systemic and regional venous metabolic acidosis was significantly ameliorated by ethyl pyruvate. Endotoxemia increased both blood nitrate + nitrite and isoprostane concentrations, and ethyl pyruvate attenuated the response of these markers of nitric oxide production and lipid peroxidation.
Conclusions: Ethyl pyruvate infusion resulted in improved hemodynamic stability and ameliorated acid-base derangements induced by chronic endotoxemia in pigs. Reduced oxidative stress and an decreased nitric oxide release probably contributed to these effects.