19.3 Parenteral and Enteral Nutrition

Total Parental Nutrition

Parenteral nutrition that includes an intravenous fat emulsion (IV administration of fat) provides complete nutritional support and so is called total parental nutrition (TPN). The provider orders the TPN daily for the patient (Figure 19.10), based on the patient’s electrolytes laboratory values. TPN rates should be strictly followed. If administered too fast, the patient can go into fluid overload (hypervolemia) and become hyperglycemic; if administered too slowly, the patient can become hypoglycemic.

Figure 19.10 This is an example of a total parenteral nutrition bag in which the glucose, amino acids, and fats are kept separate to enable room temperature storage. Before use, they are all mixed together. (credit: “Tpn 3bag.jpg” by Tristanb/Wikimedia, CC BY SA 3.0)

TPN may be administered through a central or peripheral IV site. The decision is made based on the formula prescribed by the provider and a discussion with the patient. Whichever is chosen, the purpose is to provide needed nutrients. The central line is the most likely route for TPN. The central line is inserted by the provider, then a chest x-ray is ordered and read prior to using the site. The chest x-ray ensures proper placement of the line and that placement did not cause a pneumothorax, or collapsed lung. If the chest x-ray shows a pneumothorax, the patient may require a chest tube to reinflate the lung (for more discussion, see Chapter 11 Gas Exchange, Airway Management, and Respiratory System Disorders). If the chest x-ray shows the central line is in position and there is no pneumothorax, the TPN will be started. Commonly, the central line may have a double or triple lumen so the patient can receive fluids and medications without disruption of the TPN.

Peripheral TPN, also called peripheral parenteral nutrition, is typically used for shorter-term nutritional support or for a patient who cannot tolerate a central line. If the peripheral line infiltrates, the line must be restarted promptly. A delay in restarting the IV line is a safety concern because it places the patient at risk for hypoglycemia.

Nursing Management

Administering parenteral medications, as with other injectable medications, is considered an invasive procedure. It is imperative to take additional measures when administering parenteral medications to prevent health care–associated infections. These measures include hand hygiene, prevention of needle or syringe contamination, preparation of the access site, prevention of contamination of the solution, and use of new, sterile tubing for each bag of nutrition.

Nursing management of the patient receiving parenteral nutrition includes

• verifying the appropriateness of the parenteral nutrition
• assessing the patient’s response to the infusion
• monitoring for complications, such as electrolyte imbalances or central line–associated bloodstream infection
• monitoring the patient’s glucose levels regularly and managing hypoglycemia or hyperglycemia promptly
• if administering peripheral parenteral nutrition, ensuring the site is monitored frequently and per facility protocol for signs of complications such as infiltration

Clinical Indications

Enteral feeding is indicated for patients who cannot maintain adequate oral intake to meet nutritional demands. Indications for EN include

• comatose patients with a traumatic brain injury or receiving mechanical ventilatory support
• conditions associated with higher nutritional demands, such as burns, critical illness, and cystic fibrosis
• mental illness such as dementia
• neuromuscular disorders, such as advanced Parkinson’s disease
• severe anorexia from human immunodeficiency virus (HIV), chemotherapy, or sepsis
• Upper GI obstruction, stricture, or tumor

Types of Enteral Feeding Tubes

There are several different types of EN tubes; they differ in their location in the GI system as well as their function. Three commonly used enteral tubes are the nasogastric (NG) tube, the percutaneous endoscopic gastrostomy (PEG) tube, and the percutaneous endoscopic jejunostomy (PEJ) tube (Figure 19.11).

Figure 19.11 Enteral feeding tubes can be placed through the nose or through the skin and reach several places in the digestive system. (credit: “Types and Placement of Enteral Tubes” by OpenRN/Nursing Skills, 2e, CC BY 4.0)

An NG tube is a single- or double-lumen tube that is inserted into the nasopharynx, then down through the esophagus, and into the stomach. NG tubes can be used for feeding, medication administration, and suctioning. NG tubes used for feeding and medication administration are small and flexible, whereas NG tubes used for suctioning are larger and more rigid. NG tubes are secured externally to the patient’s nose or cheek by adhesive tape or a fixation device, so this area should be assessed daily for signs of pressure damage.

Other types of tubes are placed through the patient’s abdominal wall and are used for long-term enteral feeding. A PEG tube is placed into the stomach via an endoscopic procedure. Alternatively, a PEJ tube is placed in the jejunum of the small intestine for patients who cannot tolerate the administration of enteral formula or medications into the stomach, due to medical conditions such as delayed gastric emptying.

Nursing Management

The most serious complication of enteral feeding is inadvertent respiratory aspiration of gastric contents, which can cause life-threatening aspiration pneumonia. Other complications include tube clogging, tubing misconnections, and patient intolerance of enteral feeding. To prevent tubing misconnections, the nurse should take the following precautions:

• Make tubing connections under proper lighting.
• Do not modify or adapt IV or feeding devices, because doing so may compromise the safety features incorporated into their design.
• When making a reconnection, routinely trace lines back to their origins and then ensure they are secure.
• As part of a hand-off process, recheck connections and trace all tubes back to their origins.
• Clearly label all tubing at both the proximal and distal ends (Boullata et al., 2017).

Nurses perform interventions to prevent aspiration. The American Association of Critical-Care Nurses recommends the following guidelines to reduce the risk for aspiration:

• Assess feeding tube placement at 4-hour intervals.
• Assess for GI intolerance at 4-hour intervals (Boullata et al., 2017).
• Maintain the head of the bed at 30° to 45° unless contraindicated.
• Monitor the nare for skin integrity. Adhere to facility protocol for adhesive and medical device pressure injury prevention strategies.
• Observe for change in the amount of external length of the tube. The centimeter mark at the nare should be documented and verified with at each assessment.
• Use sedatives as sparingly as possible.

Feeding tubes are prone to clogging for a variety of reasons, including size or location of the tube, insufficient water flushes, aspiration for gastric residual volume (GRV; the volume of stomach contents), contaminated formula, and incorrect medication preparation and administration. Research supports water as the best choice for initial declogging efforts (Boullata et al., 2017). If water does not work, a pancreatic enzyme solution, an enzymatic declogging kit, or mechanical devices for clearing feeding tubes are the best second-line options. To prevent EN tube clogging, the nurse should:

• Flush feeding tubes at a minimum of once a shift.
• Flush feeding tubes immediately before and after intermittent feedings. During continuous feedings, flush at standardized, scheduled intervals.
• Flush feeding tubes before and after medication administration and follow appropriate medication administration practices.
• Limit GRV checks because the acidic gastric contents may cause protein in enteral formulas to precipitate within the lumen of the tube.