[Comparative study of two lipid emulsions in patients receiving total parenteral nutrition]. / Estudio comparativo de dos emulsiones lipídicas en enfermos que reciben nutrición parenteral total.

ABSTRACT

INTRODUCTION: the use of lipid emulsions together with glucose as a calorie source in parenteral nutrition has undisputed advantages. Their isotony and high calorie content mean they are essential for peripheric parenteral nutrition and in parenteral nutrition of long duration they are important in providing essential fatty acids. OBJECTIVE: to determine the constant of elimination of two commercial lipid emulsions with similar compositions, and evaluate whether significant differences exist between them. MATERIAL, METHODS AND PATIENTS 20 candidates for total parenteral nutrition were studied over a period of at least ten days. These patients showed no severe stress, sepsis or IRA. The patients received total parenteral nutrition for at least 3 days prior to commencing the study; 12 hours after initiation, total parenteral nutrition was administered, without lipids. Afterwards, one of the emulsions studied was infused centrally (in Y with the parenteral nutrition) at a rate of 0.15 g/kg/hour for 3 hours, 24 hours later, the other emulsion was infused under the same conditions. Commencing with one or the other was done at random, and both at 10%. Blood samples were taken at the following times--10.0 (end of the infusion of the emulsion), 10, 30, 60 and 90 minutes, and the following parameters studied total cholesterol (col), triglycerides (tg) and phospholipids (pl); tg, col ad pl of the VLDL, HDL and LDL, free fatty acids and lipoprotein lipase. The analytical methods employed were ultracentrifugation with compressed air and precipitation with PEG-6000. RESULTS: significant differences were observed in the constant of elimination of total tg (2.54 +/- 0.73 in emulsion A compared to 2.8 +/- 0.66 in B), in the Kd of the VLDL tg (1.65 +/- 0.86 in A compared to 1.99 +/- 0.77 in B) and in the Kd of the VLDL P1 (0.98 +/- 0.53 in the case of A compared to 1.1 +/- 0.43 in emulsion B), no significant differences were found in the other parameters studied. The Student T was applied, and no lipase lipoprotein activity was observed. DISCUSSION: the differences found may perhaps be explained by the action of the emulgent on the intravascular metabolism of the fats. Although in both cases this is egg lecithin, the composition of this has not been studied in depth. Emulsion A = Intralipid (n. reg). Emulsion B = Tutolipid (n. reg.).