Source: Kumpf VJ and Chessman KH.
Enteral Nutrition. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells
BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=8012769.
Accessed July 28, 2012.
- Delivery of nutrients by tube or mouth into gastrointestinal
of entry: delivery through feeding tube.
- Usable fuels generated through digestion and absorption
- Digestion: stepwise
conversion of complex chemical and physical nutrients via mechanical,
enzymatic, and physicochemical processes into molecular forms that
can be absorbed from GI tract
- Absorption occurs across intestinal cell membrane.
- Nutrients reach systemic
circulation through portal venous or splanchnic lymphatic systems.
- Enteral nutrition (EN) indicated in patients who cannot
or will not eat enough to meet nutritional requirements.
- Requires functioning
- Contraindicated with mechanical obstruction and necrotizing
- EN success may be challenged with:
- Severe diarrhea
- Protracted vomiting
- Enteric fistulas
- Severe GI hemorrhage
- Intestinal dysmotility
- Advantages of EN over parenteral nutrition (PN):
- Maintaining GI tract structure and function
- Fewer metabolic, infectious, and technical complications
- Lower costs
- Initiate EN within 24–48 hours of hospitalization
for critically ill patients
- Delay EN until oral intake inadequate for 7–14 days
in mild to moderately stressed, well nourished patients.
- Provide calories, macronutrients, and micronutrients to
patients unable to achieve these requirements from oral diet.
- Enteral access
- Four routes of administration
- Indications, tube placement options, advantages, and disadvantages
in Table 1.
- Choice depends on anticipated duration of use and feeding
site (stomach vs. small bowel).
- Administration methods
- Preferred for initiation
- Well tolerated
- Increased costs due to pump and administration
- Increased mobility due to breaks from
- Commonly used in long-term care residents
with gastrostomy tube
- Minimal equipment and administration time required (5–10
- Potential side effects:
- Similar to bolus except that
administration time longer (20–60 minutes)
tolerability but more equipment
- Optimize achievement of nutrient
goals by improved GI tolerance with use of initiation and advancement
- Continuous EN feedings
- Adults: 20–50
mL/hour and advanced by 10–25 mL/hour
every 4–8 hours until goal achieved
- Children: 1–2 mL/kg/hour
- Premature infants: 10–20 mL/kg/day
- Intermittent EN feedings:
- Adults: 120 mL every
4 hours and advanced by 30–60 mL every 8–12 hours
- Children: 2–4 mL/kg
per bolus with advancement by similar amounts every 4–24
- Provide essential nutrients,
including macronutrients (e.g., carbohydrates, fats, and proteins)
and micronutrients (e.g., electrolytes, trace elements, vitamins,
- Proteins: molecular form of protein source determines amount
of digestion required for absorption within small bowel.
- Carbohydrates: provide major source of calories.
- Polymeric entities preferred over elemental sugars.
- Fat: vegetable oils most common source.
- Fiber: soy polysaccharides added to some products.
- Osmolality: function of size and quantity of ionic and molecular
particles primarily related to protein, carbohydrate, electrolyte,
and mineral content.
- Adults: 300–900 mOsm/kg
- Children: <450 mOsm/kg (450 mmol/kg)
- Classification of EN formulations
- Based on
composition and intended patient population (Table 2)
- Disease state–specific formulations designed to meet
unique nutrient requirements and manage metabolic abnormalities.
Table 1. Options and Considerations
in Selection of Enteral Access