A new intravenous emulsion containing medium-chain triglyceride: studies of its metabolic effects in the perioperative period compared with a conventional long-chain triglyceride emulsion.

The effects of carbohydrate, lipid, and nitrogen metabolism of recently available lipid emulsions containing either 50% medium-chain triglyceride (MCT) and 50% long-chain triglyceride (LCT) or 100% LCT were compared in elective surgical patients. Postoperative urinary urea excretion was similar during isocaloric MCT/LCT and LCT infusions (1.9 mg/kg/min) and was decreased compared with a standard infusion of 5% glucose (1 mg/kg/min). Plasma glucose and insulin concentrations were similar during both lipid and low dose glucose infusions. However, plasma triglyceride and nonesterified fatty acid concentrations were decreased during the MCT/LCT infusion compared with the LCT infusion, suggesting that the MCT/LCT emulsion was cleared from the circulation faster than pure LCT. Ketone body concentrations were similar during all three infusions. MCT/LCT emulsion can be safely infused perioperatively and has similar nitrogen conserving properties to LCT in these circumstances.