HYPEROXIA DURING PORCINE FAECAL PERITONITIS: III. EFFECTS ON GLUCOSE METABOLISM

Abstract

Introduction: Early goal directed therapy for septic shock aims at optimization of O2 delivery. Despite its ability to improve survival in hypodynamic shock models, pure O2 breathing has insufficiently been studied in this context, since sepsis-associated increased production of O2 radicals, the production of which is directly related to the O2 partial pressure, may impair mitochondrial respiration. Therefore we studied the effects of pure O2 ventilation on carbohydrate metabolism during hyperdynamic septic shock. Methods: After induction of faecal peritonitis, pigs were ventilated for 24 h with 100% O2 or air. During continuous i.v. infusion of stable, non-radioactively labelled 1,2,3,4,5,6-13C6-glucose, blood isotope (gas chromatography-mass spectrometry) and expiratory gas 13CO2 (non-dispersive infrared spectrometry) enrichment were measured to derive the rates of gluconeogenesis and direct aerobic glucose oxidation. Results: While the rate of gluconeogenesis progressively increased without intergroup difference, ventilation with pure O2 resulted in a significantly higher aerobic glucose oxidation rate at the end of the experiment. Conclusions: Taking into account the comparable O2 uptake in the two experimental groups, the higher glucose oxidation rate suggests that early O2 ventilation switched tissue metabolism to preferential use of glucose as an energy fuel. Since glucose oxidation provides the best ratio of ATP synthesis/O2 consumption, pure O2 ventilation may be affiliated with improved yield of energy metabolism in early septic shock. Supported by the Deutscher Akademischer Austauschdienst and the Alexander-von-Humboldt-Stiftung.