Article Archive

Summer 2008

Nutrition Options — Enteral and Parenteral Feedingss
By Carol M. Bareuther, RD
Aging Well
Vol. 1 No. 3

Only 1% of older adults who live independently are clinically malnourished. However, according to results of the National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention, 16% of community residents aged 65 and older consume less than 1,000 calories per day, an intake that puts them at high risk for undernutrition. The need for supplemental nutrition becomes even clearer in light of statistics indicating that up to 60% of older adults in hospitals and long-term care facilities are malnourished.

 When older adults are unable to eat or eat enough, enteral or parenteral nutrition is often necessary, says Christine Gerbstadt, MD, RD, an Altoona, PA-based spokesperson for the American Dietetic Association. “The goal of enteral nutrition is to use the gastrointestinal [GI] tract if and whenever possible. Parenteral nutrition therapy uses intravenous feedings when the GI tract is not usable—for example, short term after GI surgery such as a bowel resection with prolonged recovery or complications.”

Enteral Nutrition Basics
Enteral nutrition is also called tube feeding because the delivery of nutrients occurs via a small polyurethane or silicone tube. A nasogastric (NG) tube is placed into the stomach through the nose, or a gastric (G) tube is inserted surgically into the abdomen.

Jessie Pavlinac, MS, RD, CSR, manager of clinical nutrition at the Oregon Health & Science University in Portland, OR, says, “Nasogastric tubes are typically used in acute or short-term situations. G-tubes are indicated in chronic conditions such as Alzheimer’s disease, Lou Gehrig’s disease, or Parkinson’s disease, where the patient is judged to require the feeding on a long-term basis.”

Enteral feeding products typically look like canned milk shakes, but they are a specialized type of liquid food that contains proteins, carbohydrates, fats, vitamins, minerals, and more in amounts that a person needs to survive and thrive.

“These products have become more sophisticated over the years,” Pavlinac says. “For example, there are those with a higher amount of protein to promote wound healing, products with both soluble and insoluble fiber to promote beneficial bacteria in the gut, tube feeds fortified with immune enhancers such as fish oils and the amino acid glutamine, and even some for specific disease states such as diabetes, liver, or kidney disease.”

A patient’s medical condition and underlying disease determine what enteral feeding is best, as well as what amount should be given, by what method, and what should be monitored on a routine basis.

“Most enteral feedings delivered into the stomach are on a bolus basis or single larger doses at a time,” Gerbstadt says. This may be from 240 to 480 milliliters (1 to 2 cups) three to five times per day, depending on caloric and fluid needs.

When high-calorie or high-protein formulas are used or feedings are delivered into the small intestine (jejunum or duodenum) instead of the stomach, an infusion pump may be necessary to prevent complications such as diarrhea. A pump allows the feeding to be infused as a slow, controlled drip that can be administered over a 24-hour period, if needed, or over a period of eight to 10 hours while a patient sleeps.

“Most patients need to remain with the head of their beds elevated 30 degrees while receiving tube feedings into the stomach. This will lessen the risk for aspiration of the feedings into the lungs and chance of aspiration pneumonia,” Gerbstadt says.

Health professionals working with a patient prescribed enteral feeding need to coordinate with the patient at home or the nurse and dietitian in an institutional setting to plan feeds around activities such as physical, occupational, and speech therapy sessions.

“It’s important to coordinate because, for example, an unplanned two-hour break in feeding could translate into a deficit of a couple hundred calories,” Pavlinac explains. “Over time, this can lead to weight loss and loss of strength and function.” One of the best ways to determine whether a patient is getting adequate feeds is to weigh them regularly.

It is also important not to automatically think that an NG tube is uncomfortable for a patient and therefore cut therapy sessions short, Pavlinac says, because “it takes the full prescription of multidisciplinary modalities to help someone mend or regain function.” Gerbstadt adds that speech therapists “should be aware that swallowing and gag reflexes may be altered for a prolonged time after removal of a feeding tube.”

Pharmacists should be aware of potential drug-nutrient interactions. High concentrations of nutrients in enteral feedings can impair or reduce a drug’s bioavailability. For example, minerals such as calcium, magnesium, and iron in a tube feed can reduce the effectiveness of antimicrobials such as ciprofloxacin (Cipro), levofloxacin (Levaquin), and moxifloxacin (Avelox). The bioavailability of liquid phenytoin (Dilantin) can be lessened by the drug’s ability to bind with the enteral feeding’s protein component. Giving warfarin (Coumadin) with enteral feeding poses a similar problem. Holding a feeding for one to two hours before and after medication can minimize drug-enteral feeding interactions.

Parenteral Nutrition Basics
Parenteral nutrition, also called total parenteral nutrition (TPN) or hyperalimentation, involves the intravenous delivery of a full complement of nutrients—glucose, amino acids, lipids, vitamins, and minerals. This method is used when the GI tract fails to work properly. In the short term, it may be due to a condition such as peritonitis. Long term, it can result from blockages caused by malignant tumors or massive intestinal resection due to cancer or other bowel diseases.

The delivery of TPN occurs via a special intravenous catheter placed in a large vein in the chest or arm. The catheter can remain in place for as long as needed; however, it requires proper care to avoid infection and clotting. The nutrient mixture is infused with the aid of a pump at the rate of 1 to 10 milliliters per hour, depending on the elder’s needs. Fatty liver has emerged as a common complication of 24-hour feeding. Keeping the vein open requires a continuous infusion; however, feeding schedules are commonly ramped up and down during the day to simulate normal meal times.

Other long-term complications of TPN include hepatic steatosis, cholestasis, metabolic bone disease, and macronutrient or micronutrient toxicities or deficiencies.

An early discharge from the hospital results in greater numbers of patients receiving TPN at home. “Parenteral feedings need to be handled sterilely. Some nonhealthcare professionals who are trained to change tubing can do this and feedings at home. In many instances, though, a home care nurse or aide may be necessary for safety,” Gerbstadt says.

Effecting Feeding Transitions
Nutrition support methods are not necessarily mutually exclusive. Some older adults experience optimal results on a combination of feedings, such as enteral feeds with gradually increasing food intake by mouth or phasing from parenteral to enteral nutrition. It’s critical to plan gradual transitions effected in a calculated fashion with vigilant observation for complications that could send a patient’s progress spiraling backward.

Pavlinac says to keep in mind that “just because a patient is now eating by mouth, doesn’t mean they’re eating enough. It’s not always all or nothing when it comes to enteral and parenteral nutrition.”

— Carol M. Bareuther, RD, is a St. Thomas, U.S. Virgin Islands-based writer who contributes to a variety of regional, national, and international publications.


Check Points to Determine Capability for Home Nutrition Support
Health professionals can assess whether patients and their families are capable of successfully carrying out enteral or parenteral nutrition therapy at home by reviewing the following points:

• Patient motivation

• Potential improvement in the patient’s quality of life

• Third-party insurance reimbursement

• Patient’s or family’s ability to handle the financial situation

• Patient’s or caretaker’s ability to learn the protocol for feeding administration
• Ability to comply with safety standards

• Benefit of long-term nutrition support based on the patient’s condition

• Benefit of long-term nutrition support for the patient’s nutritional status

• Patient’s or caretaker’s physical limitations influencing the ability to administer nutrition support safely

— Adapted from Mahan, L. K. & Escott-Stump, S. (2007).  Krause’s Food & Nutrition Therapy. Philadelphia: WB Saunders.