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Definition

nutrition

(noo-trish'ŏn, nū- )

[L. nutritio, feeding]

  1. The ingestion and utilization of food by which growth, repair, and maintenance of activities in the body are accomplished. The body is able to store some nutrients (glycogen, calcium, iron) for times when food intake is insufficient. Vitamin C is an example of a nutrient that is not stored.

    SEE: total parenteral nutrition .

  2. The professional discipline that includes both the scientific study and the practical use of nutrients in health.

    nutritional,

    (-trish'ŏn-ăl )

    adj.

enteral n.Nutrition provided through a tube placed into the stomach or small intestine. This may be accomplished through a nasogastric tube, a percutaneous gastrostomy tube, or a jejunostomy.

exclusion enteral n.

ABBR: EEN

A form of nutrition in which a patient receives nothing by mouth but obtains all calories, minerals, and vitamins via tube feedings.

hemotrophic n.Transplacental passage of nutrients from the maternal bloodstream to the fetal circulation.

medical nThe dietary management of conditions with specific macro- and micronutrient requirements. It includes specially recommended or attended oral, enteral, and intravenous (“parenteral”) nutrients.

partial enteral n.Supplemental tube feeding or oral feeding of foods that are rich in protein, calories, and other nutrients to patients receiving partial parenteral nutrition.

SEE: enteral nutrition .

partial parenteral n.

ABBR: PPN

Intravenous administration of nutrients to patients whose nutritional requirements cannot be fully met via the enteral route. An amino acid–dextrose solution (usually 10%) and a lipid emulsion (10% to 20%) are delivered into a peripheral vein through a cannula or catheter.

total enteral n.Enteral tube feeding.

total parenteral n.

ABBR: TPN

The intravenous provision of dextrose, amino acids, emulsified fats, trace elements, vitamins, and minerals to patients who are unable to assimilate adequate nutrition by mouth. Patients with many illnesses become malnourished if they are unable to eat a balanced diet for more than a few weeks. Patients who have been hospitalized for a prolonged period, have had no oral intake for several days, or have a cachectic disorder should be assessed for the need for nutritional support. However, only a small percentage of these patients clearly benefit from parenteral nutritional support in clinical trials. Patients who benefit most from TPN are those at the extremes of nutritional risk, e.g., preterm or newborn infants who require surgery or the 5% of adult surgical cand idates who are the most nutritionally deficient. Patients who may occasionally benefit from TPN include those with inflammatory bowel disease, radiation enteritis, bowel obstruction, and related intestinal diseases. In many other patients, the anticipated risks of malnutrition and starvation are exceeded by the potential risks of TPN, which include injury during central line placement, sepsis as a result of infectious contamination of intravenous lines, and metabolic complications, e.g., refeeding syndrome.

Patients requiring 7 to 10 days of nutritional support may benefit from the administration of parenteral nutrition through a peripheral venous catheter. This method limits the caloric intensity of TPN to about 2300 kcal/day (ca. 900 mOsm/kg) because more concentrated formulas cause peripheral vein inflammation. With central TPN, patients have been occasionally supported for several months with limited overt complications. The superior vena cava tolerates feedings of up to 1900 mOsm/kg. Typically, central TPN includes individually tailored amounts of dextrose, amino acids, lipids, vitamins, trace elements, heparin, insulin, and other substances. In patients with specific diseases, some nutrients may be limited, for example, sodium (in congestive heart failure), protein content (in liver failure), and potassium (in renal failure).

The procedure is explained to the patient, and a nutritional assessment is obtained. Intake and output are monitored and recorded. The nurse assists with catheter insertion and observes for adverse effects, documents procedure and initial fluid administration, and continues to monitor fluid intake. The catheter insertion site is inspected and redressed every 24 to 48 hr according to agency protocol; a strict aseptic technique is used for this procedure. The condition of the site and position of the catheter are documented, and the catheter is evaluated for leakage; if present, this should be reported to the physician. Electrolytes are monitored. Vitamin supplements are administered as prescribed. The patient is observed for edema and dehydration. If diarrhea or nausea occurs, the infusion rate is slowed. Urine sugar and acetone tests are performed every 6 hr, and blood sugar levels are monitored as prescribed. Daily weights are obtained. The solution should never be discontinued abruptly but tapered off with isotonic glucose administered for several hours. In the event of catheter blockage or accidental removal, the physician should be notified immediately. Patients should be encouraged to ambulate. Some patients recuperating from long illnesses are released from the hospital with self-administered TPN until they are able to resume eating. These patients need to be taught how to use TPN in the home.

Although TPN is often necessary, in most instances the best way to nourish a patient is by mouth or enterally (by intestinal tube). Oral and enteral feedings preserve the integrity of the intestinal mucosa, maintain a normal pH in the stomach, prevent the entry of bacteria into the body through the walls of the gastrointestinal tract, and are less expensive than parenteral nutrition. Chronic liver failure is the most common, potentially life-threatening complication in patients who need to be maintained on TPN for more than a year.