Carnitine as a possible adjunct in parenteral feeding

The effect of carnitine supplemented total parenteral nutrition on lipid, energy and nitrogen metabolism in severely ill patients

To analyse the effects of L-carnitine supplemented TPN on lipid, energy and nitrogen metabolism, 16 severely injured patients were studied during the first 8 days after trauma. An L-carnitine solution (3g = 18.6mmol) was added to the fat emulsion and infused over 16h in a blind randomised fashion to half of the patients. Plasma triglyceride, free fatty acid and 3-OH-butyrate concentrations increased during the fat infusion, and fell to pre-infusion concentrations within 24h. There were no differences in plasma levels before, during or after infusion between the groups. ATP and phosphocreatine in muscle tissue were not influenced by carnitine supplementation. Glycogen, however, remained unchanged in the carnitine group and fell in the non-carnitine group. A cumulative N-balance measured from day 2 to day 8 was equally negative in both groups. Plasma carnitine levels were significantly higher in the supplemented group from day 3. The mean daily urinary carnitine excretion was increased 15-fold in the supplemented group. Muscle carnitine, however, remained unchanged in both groups and did not differ between them. The present results do not demonstrate any beneficial effects of parenterally administered L-carnitine on lipid, energy or nitrogen metabolism except for maintaining normal muscle glycogen levels in critically ill patients receiving TPN during the early phase after trauma.

Nutritional support in malnourished paediatric patients

An imbalance between a person's energy requirements and his or her dietary protein and caloric supply is the source of protein energy malnutrition (PEM), which compounds the problems of any underlying disease. Malnutrition may occur quite rapidly in critically ill patients, particularly those suffering from sepsis, setting up a vicious cycle with worsening of the PEM. This chapter examines the main consequences of PEM, the means whereby appropriate nutrition may be provided, and risks for severely malnourished paediatric patients in hospital. If the gastrointestinal tract can be used for refeeding, it should be used. When the gastrointestinal tract is unable to meet the protein and energy requirements, parenteral nutrition (PN) is required. PN is efficient but carries a high risk of metabolic complications known as the refeeding syndrome and directly related to the homeostatic changes secondary to severe PEM. Catch-up growth may be achieved by using appropriate nutritional support. Changes in body composition have to be assessed during the course of renutrition.

Effects of L-carnitine infusion on intralipid clearance and utilization. Study carried out in septic patients of an intensive care unit

Endogenous and exogenous supplies of carnitine are decreased in septic patients under total parenteral nutrition, while carnitine urinary elimination is increased. But the increase of lipid role in the energetic cover requires a greater intervening role of tissue carnitine. So one may hope that in septic patients additional supply of L-carnitine would increase the catabolism of infused lipids. Twenty-eight septic patients, admitted in an intensive care unit were given parenteral nutrition (200 g of glucose, 12.5 g of N/24 hr). On the day of the study, 250 ml of Intralipid 20% (Kabi Vitrum) were administered in 4 hr. During the same period 13 patients were infused with 2 g of L-carnitine (Sigma-Tau). The remaining 15 patients constituted the control group. Basic plasma levels of triglycerides, nonesterified fatty acids, free glycerol, phospholipids, and ketone bodies remained within physiological limits. They increased during the lipid infusion and returned to initial values, 4 hr after the end of the infusion. Free and total carnitine levels and free/total carnitine ratio were comparable to healthy subjects' reference values. These parameters increased during L-carnitine infusion. This infusion had no effect on exogenous lipid clearance. However, it seemed to increase the uptake and the hepatic oxidation of circulating fatty acids. It invalidated the increase of lactate and pyruvate that had been noticed when lipids were solely infused.