Hypercaloric glycerol in injured patients

This study investigates the effects of glycerol as a fuel source in the hypermetabolic patient (after injury).

Twenty-two patients were studied after multiple trauma and randomly assigned to either glucose or glycerol as the carbohydrate source (220 gm glycerol or 320 gm dextrose) during a lipid-based system of parenteral nutrition. In the immediate postoperative period, measurements were made of nitrogen balance, substrates, energy expenditure, insulin, glucagon, and liver function tests.

In the glycerol group glucose concentrations in plasma were significantly lower, whereas glycerol levels increased nearly twentyfold. Insulin and glucagon levels increased in both groups; however, the rise in insulin level was greater in the glucose group, whereas glucagon increased in both groups to a similar degree. Nitrogen balance was restored to equilibrium in the glycerol group while remaining negative in the glucose group. No abnormalities in liver function test results or differences in serum albumin levels were noted in either group. A 12% thermic effect was noted in the glucose group but not in the glycerol group.

Glycerol seems to be a viable fuel source in the traumatized patient, being associated with nitrogen retention and minimal thermal effect. A marked rise in plasma levels of glycerol does occur, but this does not appear to have any associated toxicity.