1. The metabolic effects of an intravenous lipid emulsion containing medium-chain triacylglycerols (MCT) and long-chain triacylglycerols (LCT) were studied in 16 critically ill, ventilated patients. The effects were compared in a cross-over study with those of a conventional emulsion containing only LCT.
2. The lipid was well tolerated but the metabolic effects of the MCT/LCT infusion differed from those of the LCT infusion.
3. The major differences were a 60% higher insulin concentration and a significantly greater increase in the plasma concentrations of non-esterified fatty acids during MCT/LCT infusion than during LCT infusion. The mean rise in plasma ketone concentration was also higher during MTC/LCT infusion, although this did not reach statistical significance.