Parenteral nutrition providing a restricted amount of linoleic acid in severely burned patients: a randomised double-blind study of an olive oil-based lipid emulsion v. medium/long-chain triacylglycerols

Abstract

It has been claimed that lipid emulsions with a restricted linoleic acid content can improve the safety of total parenteral nutrition (TPN). The tolerability of TPN and its effects on the metabolism of fatty acids were assessed in this prospective, double-blind, randomised study comparing an olive/soyabean oil long-chain triacylglycerol (LCT) with a medium-chain triacylglycerol (MCT)/LCT; 50:50 (w) based lipid emulsion in two groups (O and M, respectively; eleven per group) of severely burned patients. After resuscitation (48–72 h), patients received TPN providing 147 kJ/kg per d (35 kcal/kg per d) with fat (1·3 g/kg per d) for 6 d Plasma fatty acids, laboratory parameters including liver function tests, and plasma cytokines were assessed before and after TPN. Adverse events encountered during TPN and the clinical outcomes of patients within the subsequent 6 months were recorded. With both lipid emulsions, the conversion of linoleic acid in its higher derivatives (di-homo-γ-linolenic acid) improved and essential fatty acid deficiency did not appear. Abnormalities of liver function tests occurred more frequently in the M (nine) than in the O (three) group (P=0·04, Suissa–Shuster test). Seven patients (four from group O and three from group M) died as a consequence of severe sepsis 3–37 d after completion of the 6 d TPN period. When compared with the surviving patients, those who died were older (P=0·01) and hyperglycaemic at baseline (P<0·001), and their plasma IL-6 levels continued to increase (P<0·04). Although fatty acid metabolism and TPN tolerability were similar with both lipid emulsions, the preservation of liver function noted with the use of the olive oil-based lipid emulsions deserves confirmation.