Enteral Nutrition for
Adults: Administration Issues
including material from
Dietitians in Nutrition Support
A DIETETIC PRACTICE GROUP OF
AMERICAN DIETETIC ASSOCIATION
“Your link to nutrition and health.”
Contraindications for EN
 Severe acute pancreatitis
 High output proximal fistula
 Inability to gain access
 Intractable vomiting or diarrhea
 Aggressive therapy not warranted
 Expected need less than 5-7 days if
malnourished or 7-9 days if
normally nourished
ASPEN. The science and practice of nutrition support. A case-based core curriculum. 2001; 143
Contraindications for EN
 Inadequate resuscitation or
hypotension; hemodynamic
instability
 Ileus
 Intestinal obstruction
 Severe G.I. Bleed
Indicators of Adequate Fluid
Resuscitation in Critically Ill Pts
 Urine output should be >30 ml/hour
 Heart rate <120 beats/minute; preferably
<100 beats/minute
 Systolic BP should be ~100
 Ask staff/medical team
 If patient is receiving fluid boluses in
addition to continuous IVF, likely they are
not adequately resuscitated
Nasogastric Tubes
Nasogastric Tubes
Definition
 A tube inserted through the nasal passage
into the stomach
Indications:
 Short term feedings required
 Intact gag reflex
 Gastric function not compromised
 Low risk for aspiration
French Units—Tube Size
 Diameter of feeding tube is measured in
French units
 1F = 33 mm diameter
 Feeding tube sizes differ for formula types and
administration techniques
 Generally smaller tubes are more comfortable
and better suited to NG or NJ feedings
 May be more likely to clog with viscous
formula or formula mixtures
Nasogastric Tubes
Advantages:
 Ease of tube placement
 Surgery not required
 Easy to check gastric residuals
 Accommodates various administration techniques
Nasogastric Tubes
Disadvantages:
 Increases risk of aspiration (maybe)
 Not suitable for patients with compromised gastric
function
 May promote nasal necrosis and esophagitis
 Impacts patient quality of life
Nasoduodenal/Jejunal
Definition
 A tube inserted through the nasal passage through
the stomach into the duodenum or jejunum
Indications:
 High risk of aspiration
 Gastric function compromised
Nasoduodenal/Jejunal
Advantages:
 Allows for initiation of early enteral feeding
 May decrease risk of aspiration
 Surgery not required
EAL EN Tube Placement Guidelines
Critical Care
 Enteral Nutrition (EN) administered into the
stomach is acceptable for most critically ill
patients.
 If your institution's policy is to measure GRV, then
consider small bowel tube feeding placement in
patients who have more than 250ml GRV or
formula reflux in two consecutive measures.
 Small bowel tube placement is associated with
reduced GRV.
ADA EAL Critical Care Guidelines accessed 8-07
EAL EN Guidelines (Critical Care)
 Adequately-powered studies have not been
conducted to evaluate the impact of GRV on
aspiration pneumonia.
 There may be specific disease states or
conditions that may warrant small bowel
tube placement (e.g., fistulas, pancreatitis,
gastroporesis), however they were not
evaluated at this phase of the analysis.
Fair; conditional
ADA EAL Guidelines Critical Care accessed 8-07
Nasoduodenal/Jejunal
Disadvantages:
 Transpyloric tube placement may be difficult
 Limited to continuous infusion
 May promote nasal necrosis and esophagitis
 Impacts patient quality of life
Orogastric
 Tube is placed through mouth and into
stomach
 Often used in premature and small infants
as they are nasal breathers
 Not tolerated by alert patients; tubes may be
damaged by teeth
GastrostomyJejunosotomy
Enterostomy Placement
 Gastrostomy
 Jejunostomy
Gastrostomy
Definition
 A feeding tube that passes into the stomach
through the abdominal wall. May be placed
surgically or endoscopically
Indications:
 Long-term support planned
 Gastric function not compromised
 Intact gag reflex present
Gastrostomy
Disadvantages:
 May require surgery
 Stoma care required
 Potential problems for leakage or tube
dislodgment
Gastrostomy
Jejunostomy
Definition
 A feeding tube that passes into the jejunum
through the abdominal wall. May be placed
endoscopically or surgically
Indications:
 Long-term feeding option for patients at high risk
for aspiration or with compromised gastric
function
Jejunostomy
Advantages:
 Post-op feedings may be initiated immediately
 Decreased risk of aspiration
 Suitable option for patients with compromised
gastric function
 Stable patients can tolerate intermittent feedings
Jejunostomy
Disadvantages:
 Requires stoma care
 Potential problems related to leakage or tube
dislodgement/clogging may arise
 May restrict ambulation
 Bolus feedings inappropriate (stable patients may
tolerate intermittent feedings)
Determining Method of
Administration
 Feeding site
 Clinical status of patient
 Type of formula used
 Availability of pump
 Mobility of patient
Initiation of Enteral Feedings
 Dilution of enteral formulas not generally
recommended
 Initiate at full strength at slow rate and
steadily advance
 Allows achievement of goal rates more
quickly; less manipulation of formula
Administration
 Bolus
 Intermittent
 Continuous
 Cyclic
Bolus Feedings
Definition
 Infusion of up to 500 ml of enteral formula into
the stomach over 5 to 20 minutes, usually by
gravity or with a large-bore syringe
Indications:
 Recommended for gastric feedings
 Requires intact gag reflex
 Normal gastric function
Bolus Feedings
Advantages:
 More physiologic
 Enteral pump not required
 Inexpensive and easy administration
 Limits feeding time so patient is free to ambulate,
participate in rehabilitation, or live a more normal
life in the home
 Makes it more likely patient will receive full
amount of formula
Bolus
Feeding
Bolus Feeding
Disadvantages:
 Increases risk for aspiration
 Hypertonic, high fat, or high fiber formulas may
delay gastric emptying or result in osmotic
diarrhea
Initiation of Bolus Feedings
 Adults: Initiate with full strength formula 3-
8 times per day with increases of 60-120 ml
q 8-12 hours as tolerated up to goal volume;
does not require dilution unless necessary to
meet fluid requirements
 Children: Initiate with 25% of goal volume
divided into the desired number of daily
feedings; increase by 25% each day divided
among all feedings until goal volume is
reached
ASPEN Nutrition Support Practice Manual, 2005, 2nd ed, p. 78
Continuous Feedings
Indications:
 Initiation of feedings in acutely ill patients
 Promote tolerance
 Compromised gastric function
 Feeding into small bowel
 Intolerance to other feeding techniques
Continuous Feedings
Definition
 Enteral formula administration into the
gastrointestinal tract via pump or gravity, usually
over 8 to 24 hours per day
Advantages:
 May improve tolerance
 May reduce risk of aspiration
 Increased time for nutrient absorption
Continuous Feedings
Disadvantages:
 May reduce 24-hour infusion
 May restrict ambulation
 More expensive for home support
 Pumps are more accurate; useful for small-bore
tubes and viscous feedings, but many payers have
strict criteria for approval of pumps for home or
LTC use
Initiation of Continuous Feedings
 Adults: Initiate at full strength at 10-40
ml/hour and advance to goal rate in
increments of 10 to 20 mL/hour q 8-12
hours as tolerated
 Can be used with isotonic or hyperosmolar
formulas
 Children: Isotonic formula full strength at 12 mL/kg/hour and advanced by .5-1
mL/kg/hour q 6-24 hours until goal rate is
achieved
ASPEN Nutrition Support Practice Manual, 2005, 2nd ed, p. 78
Intermittent Feedings
Definition
 Enteral formula administered at specified times
throughout the day; generally in smaller volume and
at slower rate than a bolus feeding but in larger
volume and faster rate than continuous drip feeding
 Typically 200-300 ml is given over 30-60 minutes q
4-6 hours
 Precede and follow with 30-ml flush of tap water
Indications:
 Intolerance to bolus administration
 Initiation of support without pump
 Preparation of patient for rehab services or discharge
to home or LTC facility
The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition, 2005
Intermittent Feedings
Advantages:
 May enhance quality of life
– Allows greater mobility between feedings
– More physiologic
– May be better tolerated than bolus
Intermittent Feedings
Disadvantages:
 Increased risk for aspiration
 Gastric distention
 Delayed gastric emptying
Cyclic Feedings
Definition
 Administration of enteral formula via continuous drip over
a defined period of 8 to 12 hours, usually nocturnally
Indications:
 Ensure optimal nutrient intake when:
– Transitioning from enteral support to oral nutrition
(enhance appetite during the day)
– Supplement inadequate oral intake
– Free patient from enteral feedings during the day
Cyclic Feedings
Advantages:
 Achieve nutrient goals with supplementation
 Facilitates transition of support to oral diet
 Allows daytime ambulation
 Encourages patient to eat normal meals and snacks
Cyclic Feedings
Disadvantages:
 May require high infusion rates—may promote
intolerance
Enteral Feeding Tubes
 Types: pediatric vs adult; gastric vs small bowel
 Sizes: smaller sizes (5-8 Fr) for commercial products
delivered via pump; larger sizes for viscous,
blenderized, fiber-containing formulas, gravity and
bolus feedings
 Weighted vs. unweighted: it was once thought that
weighted tubes facilitated transpyloric passage; now
dictated by personal preference
 Stylet vs. no stylet: stylet facilitates tube placement
beyond the pylorus for small, flexible tubes
 Composition: silicone and polyurethane most
comfortable
Factors Affecting Tube Selection
 Will the patient be fed into the stomach or
small bowel?
 How long will the patient need tube
feedings?
 Is the patient expected to resume adequate
oral feedings?
 Who can insert feeding tubes at my
institution?
Enteral Feeding Containers
 May be rigid or
flexible
 Sterile or non-sterile
 Unbreakable,
leakproof, and
disposable
Considerations in Choosing
Enteral Feeding Containers
 Easy to fill, close and hang
 Easy to read calibrations and directions
 Appropriate size
 Adaptable tubing port
 Compatible with pump
 Requires minimal storage space
Adapted from ASPEN. The science and practice of nutrition support. A casebased core curriculum. 2001; 179
Closed Systems
Enteral Feeding Pumps
Factors in Pump Selection
 Simple to use
 Dose function
(intuitive)
 Alarm system
 Lightweight
 Long battery life
 Portable
 Volume infused
indicator
 Flow rate accurate to
within 10%
 Approved for age
range in which it will
be used
 Permanently attached
cord
Enteral Feeding Complications
 Mechanical
 Gastrointestinal
 Metabolic
 Infectious
Mechanical
 Feeding tube obstruction
 Feeding tube dislodged
 Nasal irritation
 Skin irritation/excoriation at ostomy site
Causes of Feeding Tube Obstruction
 Concentrated, viscous, and fiber-containing
feeding products
 Tube feeding contamination
 Checking of gastric residuals
 Small diameter tubes
 Powdered or crushed medication flushed through
tubes
 Acidic or alkaline medications passed through
tubes
 Tubes not routinely flushed after feedings are
stopped
Prevention of Feeding Tube
Obstruction
 Flush the feeding tube, especially before
and after medication administration and
bolus/intermittent feedings
 Use liquid formulations of medicines where
possible (but be careful of osmolarity)
 Do not mix medications with enteral
feedings unless shown to be compatible
 Avoid crushing sustained-release or entericcoated tablets
Treatment of
Feeding Tube Obstruction
 Declog with irrigants (warm water) or
sodium bicarbonate/pancrealipase mixture
or by mechanical means
 Cola beverages, cranberry juice, and tea not
recommended
The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition, 2005
Aspiration
 Reported incidence of aspiration in tubefed
patients varies from .8% to 95%. Clinically
significant aspiration 5% gastric-fed pts
 Many aspiration events are “silent” and
often involve oropharyngeal secretions
 Symptoms include dyspnea, tachycardia,
wheezing, rales, anxiety, agitation, cyanosis
 May lead to aspiration pneumonia
Aspiration
 Focus has been on detection of aspiration through
use of coloring agents in enteral feedings or
glucose testing of respiratory secretions
 These methods have low sensitivity and
questionable specificity; they do not prevent
aspiration but at best detect it after it has occurred
 Blue food coloring used for this purpose has been
associated with morbidity/mortality in septic
patients
Aspiration Prevention
 Keep head of bed elevated 30-45 degrees
during and 30-40 minutes after feedings
 Feed post-pylorically (research mixed on
this)
 Small, frequent feedings or continuous drip
 Use of promotility agents
 Monitoring of gastric residuals may be
helpful in identifying delayed gastric
emptying and increased risk of aspiration
The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition, 2005
Gastrointestinal Complications
 Diarrhea
 Constipation
 Gastric distention/bloating
 Gastric residuals/delayed gastric emptying
 Nausea/vomiting
Diarrhea
 Definition: >500 ml every 8 hours or more than 3
stools a day for at least two consecutive days.
Relates more to stool consistency than frequency
 Diarrhea was a common consequence of enteral
feedings when hyperosmolar feedings were
routinely delivered via syringe
 Occurs in 2 to 63% of enterally-fed pts depending
on how defined
Causes/Treatments of Diarrhea
 Intestinal atrophy due to malnutrition
– EN is the best stimulant for recovery. Increase
rate slowly as tolerated
– Albumin infusion is unlikely to be helpful;
diarrhea is not caused by low albumin; it is a
marker of malnutrition
 Bolus feeding in the small intestine: results
in dumping syndrome.
– Use an infusion pump to regulate flow
The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition, 2005
Causes/Treatments of Diarrhea
 Bacterial overgrowth of intestinal tract or
contamination of the enteral feeding
– Avoid prolonged use of broad-spectrum
antibiotics
– Use clean technique and closed system in
handling enteral feedings
– Limit hang time of open system formulas to 8
hours (4 hours for mixtures)
– Change bag and tubing per protocol
– Test for C difficile and other pathogens before
using anti-motility agents
Causes/Treatments of Diarrhea
 Steatorrhea: characterized by frothy,
odiferous stools that float on water; caused
by fat intolerance
– Use lowfat enteral formula or one with higher
percentage of MCT; pancreatic enzymes may
help in pancreatic insufficiency
Causes/Treatments of Diarrhea
 Lactose intolerance
– Most enteral products are lactose free but this
may occur with initiation of full liquid diet.
Eliminate milk and dairy products
 Drug-induced diarrhea
– Meds may cause up to 61% of diarrhea in
tubefed pts due to hypertonicity or direct
laxative action (magnesium, sorbitol,
potassium). Diarrhea most common with
antibiotics. Discuss with MD/pharmacist
The A.S.P.E.N. Nutrition Support Practice Manual, 2nd Edition, 2005
Causes/Treatments of Diarrhea
 Infusion of hypertonic feeding solutions;
rare unless delivered at very high rate or
bolused into small bowel
– Try a different product rather than diluting the
original feeding
 GI disease: such as IBS, short gut, celiac
disease, AIDS
– May require PN or specially formulated EN
Treatment of Diarrhea in General
 Add soluble fiber (such as banana flakes or
Benefiber) or insoluble fiber such as
psillium
 Consider an enteral formula with added
fiber
 Use an antidiarrheal agent (loperamide,
diphenoxylate, paregoric, octreotide)
 Change the formula
Nausea/Vomiting
 20% of patients on EN report
nausea/vomiting
 Often related to delayed gastric emptying
caused by hypotension, sepsis, stress,
anesthesia, medications (analgesics and
anticholinergics), surgery
Nausea/Vomiting Treatment
 Consider reducing/discontinuing narcotic
medications
 Switch to a lowfat formula
 Administer feeding solution at room
temperature
 Reduce rate of infusion by 20-25 ml/hr
 Administer prokinetic agent (metoclopramide,
erythromycin, domperidone, bethanechol)
 Check gastric residuals
 Consider antiemetics
Metabolic
 Fluid and Electrolyte abnormalities
 Glucose intolerance
 Ca++, Mg++, PO4 abnormalities
 Other
Fluid and Electrolyte
Disturbances
 May result from long term nutrition deficits,
acute stress, medications, medical
conditions, improper nutrient prescription
 Electrolytes lost via stool, urine, ostomy or
fistula drainage
 Dehydration most common complication
(tube feeding syndrome) especially with
high protein feeding and insufficient fluid
Hyperglycemia
 Often reflects acute stress, infection, medications
(especially steroids) or latent diabetes
 Macronutrient distribution: is generally not the
primary issue; most enteral feeding formulas fall
within established guidelines; could try formula
lower in carbohydrate
 Insulin management
Refeeding Syndrome
 At risk: when refeeding those with marginal
body nutrient stores, stressed, depleted
patients, those who have been unfed for 710 days, persons with anorexia nervosa,
chronic alcoholism, weight loss
 Symptoms: Hypokalemia,
hypophosphatemia and hypomagnesemia;
cardiac arrhythmias, heart failure; acute
respiratory failure
Refeeding Syndrome
 Correct electrolyte abnormalities (via oral,
enteral, parenteral route) before initiating
nutrition support
 Administer volume and energy slowly
 Monitor pulse rate, intake and output, and
electrolyte levels
 Provide appropriate vitamin
supplementation
 Avoid overfeeding
Infectious Complications
 Formula contamination
 Unsanitary equipment
 Failure to follow appropriate protocols re handling
of enteral feedings/changing of bags and tubing
Monitoring of Patients on EN
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Electrolytes
BUN/Cr
Albumin/prealbumin
Ca++, PO4, Mg++
Weight
Input/output
Vital signs
Stool frequency/consistency
Abdominal examination
Evaluating Adequacy of Support
 I’s and O’s (what % of prescribed feeding did
patient receive?)
 Indirect calorimetry
 Nitrogen balance
 Weight
 Visceral proteins
 Other
Home Support
 Discharge planning
– May work with DME company to identify
whether patient is a candidate for home EN,
assure availability of product; complete
CMN form in conjunction with physician
 Patient education
– Patients going home on enteral feedings
will need education on food safety, feeding
administration, and self-monitoring
 Reimbursement
Enteral Support Summary
 Preferred method of nutrition support
 Technology exists to facilitate
implementation
 Can be successfully employed with careful
patient and formula selection