Whole body and regional O2 uptake/delivery and lactate flux in endotoxic dogs.

Abstract

We infused endotoxin into anesthetized dogs while maintaining cardiac output. Whole body O2 uptake and arterial lactate concentration were measured at the same time with regional O2 uptake and lactate fluxes in muscle and gut. Even though whole body O2 uptake increased, so did arterial lactate levels. The different behavior of organ systems was marked by the fact that muscle took up lactate while its O2 uptake didn't change whereas gut produced lactate as it decreased its O2 uptake. Comparison with critical levels of O2 delivery and O2 extraction ratio for whole body and the two regions opened considerable doubt that generalized and significant hypoxia explained the rise in arterial lactate. Addition of mild hypoxic hypoxia also neither caused O2 uptake to fall nor lactate to rise which reinforced our conclusion that there was little or no tissue hypoxia in endotoxin treated animals given adequate resuscitation with red blood cells and colloid solutions.