[Usefulness of fat infusion within the frame of parenteral feeding]

The interactions of fat and carbohydrate metabolism are surveyed. The posttraumatic metabolism is characterized by a stress induced high lipolytic rate and a high concentration of non-esterified fatty acids in the blood. The increased fatty acid oxidation causes by effects of metabolites a catabolic situation with enhanced ketogenesis, gluconeogenesis and protein breakdown. High levels of fatty acids and ketone bodies reduce peripheral glucose utilization. In such a situation, infusions of fat emulsions are disadvantageous, since fatty acids, set free from the triglycerides, would aggravate the catabolic metabolism and change the nitrogen balance for the worse. In normal metabolic situations with high energy need, or in long term parenteral nutrition, fat infusions are necessary to meet the needs of energy and of essential fatty acids. Fat infusions shoudl be combined with carbohydrates and amino acids in an appropriate relation.