Maximizing efficacy from parenteral nutrition in critical care: Appropriate patient populations, supplemental parenteral nutrition, glucose control, parenteral glutamine, and alternative fat sources

Abstract

The gastrointestinal tract is the preferred route for nutritional support in hospitalized patients. Patients with a functioning gastrointestinal tract, including those with pancreatitis or inflammatory bowel disease and those receiving chemotherapy, should be fed enterally. Parenteral nutrition (PN) should be limited to patients with gastrointestinal failure, including those with short gut syndrome, high-output fistula, prolonged ileus, or bowel obstruction. PN is associated with numerous complications, most notably increased risk of serious infection. Emerging data suggest that immunologic complications of PN may result from hyperglycemia and use of n-6 polyunsaturated fatty acids. Safety may be improved with a low-calorie formula and ensuring tight glycemic control with an insulin protocol. A lipid emulsion containing fish oil, olive oil, or both should replace soybean-containing emulsions. Supplemental glutamine, 0.2 g/kg/d to 0.5 g/kg/d, has been shown to reduce the risk of infection and to improve glycemic control.

Effects of glutamine on markers of intestinal inflammatory response and mucosal permeability in abdominal surgery patients: A meta-analysis

“…Glutamine (Gln) is a free amino acid that comprises >50% of the body's free amino acid pool (2). Gln is a precursor for protein synthesis and is a preferential energy source for immune and mucosal cells.…”

The Impact of Glutamine Dipeptide–Supplemented Parenteral Nutrition on Outcomes of Surgical Patients

“…Glutamine (GLN) is the most abundant free amino acid in humans, contributing more than 50% of the body's free amino acid pool 1 . GLN has traditionally been regarded as a nonessential amino acid because it can be synthesized in vivo using other essential amino acids.…”

Inflammatory Response Using Different Lipid Parenteral Nutrition Formulas in Children After Hematopoietic Stem Cell Transplantation

“…However, adverse effects on patient outcomes, mostly immune defenserelated impairment and altered inflammatory responses (4), have been attributed to the administration of lipids. Some studies suggest that PN-related immune complications may be due to n-6 polyunsaturated fatty acids (n-6 PUFA) support in PN formulations (5).…”