Use of glycerol in peripheral parenteral nutrition

Peripheral parenteral nutrition avoids the use of central lines and is a useful means of nutritional support for selected patients. Amino acids alone have been used for peripheral parenteral nutrition and have been shown to give near nitrogen equilibrium. The addition of small amounts of dextrose to amino acids further improves nitrogen balance, but at the expense of making the solutions unsterilizable and unstable by standard techniques. Glycerol is a nonprotein calorie source that can be autoclaved with amino acids and stored. Fasting patients about to undergo major abdominal surgery were randomly allocated to receive 3% amino acids with or without 3% glycerol. The solution was infused by peripheral vein for 5 days, starting the morning following surgery. Routine monitoring, blood tests, and nitrogen balance tests were performed during this time. No adverse reactions to either solution were encountered. Liver function tests, electrolytes, and hematologic values were similar in both groups. The cumulative nitrogen balance was better in the amino acid plus glycerol group (+5 +/- 3.3 gm) than in the amino acid group (-9.7 +/- 3 gm) (P less than 0.02). Serum insulin levels were higher and serum free fatty acids lower in the amino acid plus glycerol group. Glycerol levels rose and plateaued by the third day in the amino acid plus glycerol patients. Amino acids plus glycerol is safe solution to administer by peripheral vein. The addition of glycerol improves nitrogen balance as compared to amino acids alone.