Chapter 160: Enteral Nutrition

KEY CONCEPTS

• The gastrointestinal (GI) tract defends the host from toxins and antigens by both immunologic and nonimmunologic mechanisms, collectively referred to as the gut barrier function. Whenever possible, enteral nutrition (EN) is preferred over parenteral nutrition (PN) because it is associated with a lower risk of metabolic and infectious complications and is less expensive and invasive.

• Candidates for EN are those with a sufficiently functioning GI tract to allow adequate nutrient absorption who cannot or will not eat and in whom enteral access can be safely obtained.

• Critically ill patients benefit from early initiation of EN. It is acceptable to deliver EN at low rates (eg, trophic feeds) for the first week in most ICU patients. However, this method may not be appropriate for severely malnourished patients who should have their EN advanced to goal as quickly as tolerated.

• The most common route for both short- and long-term EN access is directly into the stomach. The method of delivery may be continuously via an infusion pump, intermittently via a pump or gravity drip, or bolus administration via gravity or syringe.

• Patients unable to tolerate tube feeding into the stomach because of impaired gastric motility may benefit from feeding tube placement into the duodenum or jejunum. When feeding into the small bowel, the continuous method of delivery via an infusion pump is required to enhance tolerance.

• Selection of the enteral feeding formulation depends on nutritional requirements, the patient's primary disease state and related complications, and nutrient digestibility and absorption. A standard polymeric formulation will be appropriate for the majority of adults.

• Management of diarrhea in patients receiving EN should focus on identification and correction of the most likely cause(s). Tube feeding–related causes include too rapid delivery or advancement, intolerance to the formula composition, and occasionally formula contamination.

• Medication administration through a feeding tube requires selection of an appropriate dosage form and verification of appropriate enteral access. Medications that should not be crushed and administered through a tube include enteric-coated or sustained-release capsules or tablets and sublingual or buccal tablets.

• The coadministration of medications with EN can result in alterations in bioavailability and/or changes in the desired pharmacologic effects. Medications known to interact with EN include phenytoin, warfarin, levothyroxine, select antibiotics, antacids, and proton-pump inhibitors.

Preclass Engaged Learning Activity

Visit the “Feeding Tube Awareness Foundation” website and navigate to “Tube Feeding Basics.” The webpage contains information on each type of feeding tube. The information is presented in a patient education format and is useful to enhance student understanding of the types of feeding tubes available, how these appear when inserted into a patient, and general clinical and patient considerations for each tube. This will aid in the COLLECT and ASSESS steps in the patient care process.