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

Abstract

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.