Enteral Nutrition


Nutrition Support Routes

Nutrition support is the provision of enteral (EN) or parenteral  nutrition (PN) to treat or prevent malnutrition. Nutrition support may be used to supplement oral intake. If the individual cannot eat, it can provide all of that individual’s nutritional requirements.

A basic flow diagram for assessment of nutrition support is presented below. This flow diagram can be impacted by a variety of variables but is a good representation of how to assess for enteral or parenteral nutrition.  In consideration of more complex patients, you should use this diagram as a starting point for an assessment, not a comprehensive tool for decision making.

"Assessment of Nutrition Support Route" flow diagram. Long description is below.
Flow diagram of how to assess nutrition support route.  A full text description of the steps are presented below .

Enteral Nutrition

Enteral Nutrition is liquid nutrition provided through the GI tract via a tube, catheter, or stoma. This is the recommended route of nutrition support for patients with functional GI tracts.  If the gut works, use it!

EN is associated with reduced infectious complications, and helps to maintain:

  • gut integrity (supports gut barrier function)
  • normal digestive and absorptive capabilities
  • gut-associated immune function

Indications & Contraindications

Indications for enteral nutrition include a functional GI tract and clinical conditions in which oral intake is impossible, inadequate or unsafe.

Such clinical conditions include:

  • Neurological disease/ dysfunction (e.g. stroke, dysphagia, head trauma, head and neck cancer, decreased level of consciousness)
  • Respiratory dysfunction (e.g. respiratory failure, mechanical ventilation)
  • GI disease
    • Ileus or obstruction (feed distally)
    • Short bowel syndrome (>100 cm small bowel)
    • Low output enterocutaneous fistula (<500 mL per day)
    • Pancreatitis (small bowel feeding)

Contraindications for enteral nutrition include, but are not limited to:

  • Non-operative mechanical GI obstruction
  • Intractable vomiting/ diarrhea refractory to management
  • Severe short bowel syndrome (<100 cm small bowel)
  • Paralytic ileus
  • Distal high output fistula (too distal to bypass with feeding tube)
  • Severe GI bleed
  • Severe GI malabsorption
  • Cannot gain access to the GI tract
  • Aggressive intervention not warranted/ desired

Routes of Enteral Feeding

Three types and placements of enteral feeding tubes are shown. 1. A nasogastric tube (NGT) is placed up the nose into the nasal cavity, and continues down the esophagus before ending in the stomach. 2. A percutaneous endoscopic gastrostomy (PEG) tube is placed through the skin of the upper abdomen into the stomach. 3. A percutaneous endoscopic jejunostomy (PEJ) tube is placed through the lower abdomen and into the jejunum of the small intestine.
“Types and Placement of Enteral Tubes.png” by Meredith Pomietlo for Chippewa Valley Technical College is licensed under CC BY 4.0

Enteral feeding tubes may enter the body at several different sites. The choice of enteral feeding route depends on several factors, such as the intended duration of nutrition support, the patient’s condition, and any limitations to access (such as trauma or obstructions).

Sites of Delivery

Overview of enteral sites of delivery
Sites of delivery Access types Indications Advantages Disadvantages
  • Nasogastric (NGT)
  • Orogastric tube (OGT)
  • Percutaneous Endoscopic Gastrostomy (PEG)
  • Gastrostomy tube (G-Tube)
  • Patients with normal emptying of gastric and duodenal contents
  • Large reservoir capacity of the stomach
  • Maintains normal gut function
  • Most cost effective
  • Easiest to insert
  • PEG/G-Tube decreases the risk of tube displacement
  • Can give bolus feeds
  • Increased risk of esophageal reflux and/or pulmonary aspiration
  • NGT may result in discomfort for patient and tube displacement
  • PEG/ G-Tube increases risk of irritation and infection at insertion site
(small bowel)
  • Nasoduodenal tube (NDT)
  • Oroduodenal tube (ODT)
  • Patients who have impaired gastric emptying or who are at risk of esophageal reflux
  • Normal intestinal function, need to bypass stomach
  • Can be used for early enteral feeding
  • May reduce risk of esophageal reflux or pulmonary aspiration
  • May require a pump to control feeding rate
  • May require fluoroscopic or fibre-optic endoscopic placement of tube
  • Risk of displacement/migration back into stomach
  • No gastric acid barrier against bacteria
(small bowel)
  • Nasojejunal tube (NJT)
  • Jejunostomy tube (J-Tube)
  • Percutaneous Endoscopic Gastrostomy with jejunal extension (PEJ)
  • Normal intestinal function, need bypass the stomach
  • Can bypass an upper GI surgical site, obstruction, pancreas
  • Can be used for early enteral feeding
  • May improve tolerance to enteral feeding to meet nutritional requirements and avoid parenteral nutrition
  • Potential gastrointestinal intolerance (bloating, cramping, diarrhea) due to lack of reservoir capacity
  • Requires a pump to control feeding rate
  • May require fluoroscopic or fibre-optic endoscopic placement of tube
  • Risk of displacement/migration back into stomach
  • No gastric acid barrier against bacteria

Delivery Methods

Overview of delivery methods, by feeding type
Type of Feeding Explanation Advantages Disadvantages
Continuous Feeding
  • Defined as feeding over 20-24 hours either by gravity drip or a feeding pump
  • Continuous feeding at a low volume is often used when starting an enteral feeding regime
  • It is the preferred method of delivery for GI intolerance, critical illness and some medical conditions
  • Allows the lowest possible hourly feeding rate to meet nutrient requirements
  • Better gastrointestinal tolerance due to the low feeding rate
  • Physical attachment to the feeding apparatus (may affect quality of life)
  • Expense of equipment (pump and giving sets)
Cyclic/ Intermittent Feeding
  • Defined as feeding over 8-20 hours
  • Cyclic feeding involves continuous feeding over a shorter time period
  • Intermittent feeding involves breaks in continuous feeding administration i.e. being fed over 4 hours 3 times a day for a total of 12 hours.
  • Suitable for pump and gravity drip
  • Allows freedom from feeding equipment (may improve quality of life)
  • Provides breaks for physical activity, movement, medication administration with drug-nutrient interactions, lying flat to sleep, and hunger/satiety to encourage oral intake if applicable.
  • Useful in the transition from continuous to bolus feeding, or from tube feeding to oral intake
  • A higher infusion rate is required to provide the same volume of nutrition
  • Nutritional regimes may have a period of decreased tolerance as the patient adjusts to the new feeding rate
Bolus Feeding
  • A prescribed volume of feed, administered in a shorter feeding time (such as 100-400ml over 15-60 minutes), which may be repeated in intervals to achieve the required volume
  • Usually fed into the stomach
  • Physiologically resembles a more typical eating pattern promoting hunger/ satiety
  • Allows greatest freedom from feeding equipment
  • Can be used to supplement oral intake
  • Can be more flexible to suit the patient’s lifestyle and improve quality of life
  • Large boluses may be poorly tolerated, especially in small bowel feeding
  • Some risk of aspiration, reflux, abdominal distension, diarrhea and nausea

Enteral Nutrition Assessment

When starting an enteral nutrition assessment, it is important to use a systematic process:

  1. Complete a thorough nutrition assessment: past medical history, history of presenting illness, laboratory values, medications, nutrition history, anthropometrics, physical assessment, risk of refeeding syndrome,  medical plan, and disposition.
  2. Determine feeding access: gastric vs. small bowel (duodenal vs. jejunal); short term or long term.
  3. Determine protein, energy, fluid requirements.
  4. Check for other sources of nutrients: IV infusions or solutions, medications.
  5. Formula selection
  6. Determine appropriate delivery method: continuous, cyclic, intermittent, gravity, bolus.

Depending on your patient, you may need to consider other factors in your assessment. However, this is a general representation of the assessment process.

Background complete! Feel free to review any resources and move to the next section, “Assess”, when you are ready.



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Preparation for Dietetic Practice Copyright © by Megan Omstead, RD, MPH is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.