Lipid emulsions and reticuloendothelial system function in healthy and burned guinea pigs

The effect of total parenteral nutrition (TPN) regimens containing various quantities of long-chain triglyceride (LCT) and medium-chain triglyceride (MCT) emulsions on bacterial clearance and organ sequestration was evaluated in healthy and burned guinea pigs. In healthy guinea pigs, increasing the LCT component of TPN to 75% or greater of the nonprotein calories resulted in hepatomegaly, splenomegaly, a significant reduction in the sequestration of intravenously administered Pseudomonas aeruginosa by the liver and spleen, and a markedly increased clearance of bacteria into the lung. In burned guinea pigs, replacement of LCT with MCT emulsions at 75% of the nonprotein caloric intake reduced the sequestration of bacteria in the lung and restored to normal hepatic and splenic uptake. These results suggest that LCT emulsions at 75% of nonprotein calories result in reticuloendothelial system overload and increased bacterial sequestration in the lungs in normal and burned animals. In contrast, administration of MCT emulsions to the burned animal is less likely to result in increased pulmonary sequestration and decreased hepatic or splenic reticuloendothelial system function.