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Upon completion of this chapter, the reader will be able to:

  1. Discuss how gut structure and function impact choice of feeding route and outcome of feeding.

  2. Estimate kilocalorie and protein requirements of an enteral feeding candidate and design an enteral nutrition (EN) regimen to meet these.

  3. Evaluate patient-specific parameters to determine whether EN is appropriate.

  4. Compare clinical efficacy, complications, and costs of EN versus parenteral nutrition (PN).

  5. Formulate a monitoring plan for an EN patient.

  6. Select appropriate medication administration techniques for an EN patient.




  • Image not available. EN is the preferred route if the gut can be used safely in a patient who cannot meet nutritional requirements by oral intake.

  • Image not available. EN is associated with fewer infectious complications than PN.

  • Image not available. For patients intolerant of gastric feedings or in whom the risk of aspiration is high, feedings delivered with the tip of the tube in the jejunum are preferred.

  • Image not available. Standard EN formulas are polymeric formulas; these are appropriate for most patients.

  • Image not available. When choosing an EN formula, the patient's fluid status should dictate the caloric density selected.

  • Image not available. Robust clinical trial data supporting the use of specialty formulas in niche populations typically remain lacking in terms of improved patient outcomes.

  • Image not available. Acceptance of enteral immunonutrition in certain clinical settings is gaining momentum.

  • Image not available. Gastrointestinal complications are the most common complications of EN limiting the amount of feeding patients receive.

  • Image not available. An important practice to help prevent medication-related occlusion is adequate water flushing of the tube before, between, and after each medication is given through the tube.

  • Image not available. Compatibility of medications with an EN formula is of concern when administering medications through feeding tubes.


Enteral nutrition (EN) is broadly defined as delivery of nutrients via the gastrointestinal (GI) tract. This includes normal oral feeding as well as delivery of nutrients in liquid form by tube. Sometimes when the term enteral nutrition is used, only tube feedings are included; hence, the terms enteral nutrition and tube feedings are often used synonymously. The bulk of this chapter includes information regarding delivery of feedings via tubes. Formulas for EN usually are delivered in the form of commercially prepared liquid preparations, although some products are produced as powders for reconstitution. Modern techniques for enteral access, both placement of the tubes and the materials for making pliable, comfortable tubes, were developed in the 1960s to 1980s. Nonvolitional feedings in patients who cannot meet nutritional requirements by oral intake include EN and parenteral nutrition (PN), which are collectively known as specialized nutrition support (SNS).


Several organizations have issued clinical guidelines on the use of EN. These include the American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.), European Society for Clinical Nutrition and Metabolism (ESPEN), and Canadian team known as Critical Care Nutrition.1,2,3, and 4 A.S.P.E.N. and the Society for Critical Care Medicine (SCCM) have jointly issued guidelines for SNS in critically ill patients.5

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