Short-term TPN containing n-3 fatty acids ameliorate lactic acidosis induced by endotoxin in guinea pigs

We evaluated the effect of total parenteral nutrition (TPN) enriched with n-3 fatty acids on the physiologic response to endotoxin in guinea pigs. Animals were randomly assigned to receive TPN differing only in lipid source for 3.5 d. Group 1 received soybean fat emulsion (Intralipid) whereas group 2 received fish (menhaden) oil. During the last 7 h of TPN, animals were further randomized to have either saline or E coli endotoxin added to the infusate. Acid-base status and serum lactate concentrations were determined. Animals infused with soybean fat emulsions and endotoxin developed a significant metabolic acidosis, lactic acidemia, and decrease in mixed venous O2 compared with controls and fish-oil-treated animals (p less than 0.05). The significantly reduced serum lactate and higher mixed venous O2 in fish-oil-infused animals suggests that the underlying mechanism involves improvement in endotoxin-induced tissue hypoperfusion, presumably through alterations in prostaglandin metabolism.