Background Information

Technology to administer parenteral nutrition in the homecare setting was first developed during the late 1960s and early 1970s to meet the need for life-saving and supportive intravenous nutrition therapy.[1] [3] [4] Home parenteral nutrition therapy has now been conducted safely and effectively for more than 25 years.[5] [6] [7]

The infusion of nutrients directly into the bloodstream provides nutrition support to patients who are malnourished or at risk for becoming malnourished and are unable to maintain nutritional status through oral and/or enteral feeding. Formulations typically include carbohydrate (dextrose), protein (amino acids), fat emulsions, electrolytes and micronutrients (vitamins, minerals, trace elements).

Intravenous nutrition support can be provided peripherally or centrally. Peripheral parenteral nutrition (PPN) support for longer periods of time can be problematic. Generally, peripheral parenteral nutrition support is provided for short periods of time to lower at- risk patients who are not severely malnourished and can tolerate larger fluid loads. Calories and other nutrients may be less complete because a lower osmolarity (less than 900 mOsm/L) is required to safely provide nutrients through a peripheral vein. In order to provide adequate amounts of nutrients, a larger volume of hyperosmolar fluids is required, often including fat emulsions.

TPN is generally delivered into the superior vena cava, which allows for higher concentrations of nutrients and for prolonged therapy (weeks to years in duration). Indications for TPN include: an inability to orally or enterally meet nutritional needs due to malabsorption, the need for bowel rest, or conditions that prohibit adequate oral or enteral feeding for more than seven days. In cases of critical illness where hypermetabolism is expected to continue for more than four to five days, parenteral nutrition can be initiated.

In addition to treatment for malnutrition, TPN can be used as a preventive therapy. For instance, pre-surgical support for patients with pre-existing malnutrition may improve outcomes. Cancer patients who experience treatment-related gastrointestinal toxicity may be able to prevent problems associated with nutritional decline if TPN is initiated early.

----------------------------