Glucose-lipid ratio is a determinant of nitrogen balance during total parenteral nutrition in critically ill patients: a prospective, randomized, multicenter blind trial with an intention-to-treat analysis

Intensive Care Med. 2005 Oct;31(10):1394-400. doi: 10.1007/s00134-005-2771-5. Epub 2005 Aug 24.


Objective: Protein sparing, the major goal of nutritional support, may be affected by the glucose/lipid ratio. This study in critically ill patients compared the efficacy and tolerance of two isocaloric isonitrogenous total parenteral nutritions (TPN) having different glucose/lipid ratios.

Design: Multicentric prospective randomized study.

Patients: 47 patients with SAPS I score higher than 8 and requiring exclusive TPN.

Interventions: Patients received glucose/lipid ratios of 50/50 or 80/20. For 7 days all patients received 32 glucidolipidic kcal/kg and 0.27 g/kg nitrogen daily. All-in-one bags were prepared using industrial mixtures and a fat emulsion.

Measurements and results: We determined TPN efficacy by nitrogen balance, urinary 3-methylhistidine/creatinine ratio, transthyretin and tolerance by glycemia, and liver enzymes. After controlling for five variables with significant effects, patients receiving the 50/50 ratio during TPN had significantly higher nitrogen balance than those receiving the 80/20 ratio. The daily difference in mean nitrogen sparing effect in favor of the latter group was 1.367 g (95% CI 0.0686-2.048). Glycemia on day 4 and gamma-glutamyltranspeptidase on day 8 were higher in group receiving the the 80/20 ratio.

Conclusions: In critically ill patients TPN at a glucose/lipid ratio of 80/20 ratio induces a small nitrogen sparing effect compared to the ratio of 50/50, at the expense of poorer glycemic control. The clinical significance is unclear.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Critical Care*
  • Dietary Fats / administration & dosage
  • Dietary Fats / metabolism*
  • Female
  • Glucose / administration & dosage*
  • Humans
  • Male
  • Middle Aged
  • Nitrogen / metabolism*
  • Parenteral Nutrition, Total*
  • Severity of Illness Index
  • Single-Blind Method


  • Dietary Fats
  • Glucose
  • Nitrogen