Transcript Introduction to Enteral Nutrition

Introduction to Enteral Nutrition
Enteral Nutrition

Nutrition delivered via the gut

Includes oral feedings and tube feedings
Enteral Tube Feeding

Nutritional support via tube
placement through the nose,
esophagus, stomach, or intestines
(duodenum or jejunum)
—Must have functioning GI tract
—IF THE GUT WORKS, USE IT!
—Exhaust all oral diet methods first.
Oral Supplements

Between meals

Added to foods

Added into liquids for medication pass
by nursing

Enhances otherwise poor intake

May be needed by children or teens to
support growth
Diagram of enteral tube placement.
Copyright © 2000 by W. B. Saunders Company. All rights reserved.
Fig. 22-2. p. 468.
Conditions That Require Specialized
Nutrition Support

Enteral
—Impaired ingestion
—Inability to consume adequate nutrition
orally
—Impaired digestion, absorption, metabolism
—Severe wasting or depressed growth

Parenteral
—Gastrointestinal incompetency
—Hypermetabolic state with poor enteral
tolerance or accessibility
Algorithm for Decisions
Modified and adapted from Gorman RC, Morris JB: Minimally invasive access to the gastrointestinal tract. In Rombeau JL,
Rolandelli RH, editors: Clinical nutrition: enteral and tube feeding, p 174, Philadelphia, 1997, WB Saunders; and Ali A et al:
Nutritional support services, Nutritional Support Algorithms, 8(7):13, July 1998.
Indications for Enteral Nutrition
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Malnourished patient expected to be
unable to eat >5-7 days
Normally nourished patient expected to
be unable to eat >7-9 days
Adaptive phase of short bowel syndrome
Increased needs that cannot be met
through oral intake (burns, trauma)
Inadequate oral intake resulting in
deterioration of nutritional status or
delayed recovery from illness
ASPEN. The science and practice of nutrition
support. A case-Based Core curriculum. 2001; 143
Contraindications for EN
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Severe acute pancreatitis
High output proximal fistula
Inability to gain access
Intractable vomiting or diarrhea
Aggressive therapy not warranted
ASPEN. The science and practice of nutrition support. A case-based core curriculum. 2001; 143
Contraindications for EN
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Inadequate resuscitation or
hypotension; hemodynamic instability
Ileus
Intestinal obstruction
Severe G.I. Bleed
Expected need less than 5-7 days if
malnourished or 7-9 days if normally
nourished
Advantages - Enteral vs PN

Preserves gut integrity
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Possibly decreases bacterial translocation
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Preserves immunological function of gut
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Reduces costs (EAL Grade II)
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Fewer infectious complications in critically ill
patients (EAL Grade I)
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Safer and more cost effective in many settings
ASPEN. The science and practice of nutrition support. A case-based core curriculum. 2001;
147
ADA EAL, Critical Illness, accessed 8-07
Advantages—Enteral Nutrition
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Intake easily/accurately monitored
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Provides nutrition when oral is not
possible or adequate
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Supplies readily available
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Reduces risks associated with
disease state
Disadvantages—Enteral Nutrition
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GI, metabolic, and mechanical
complications—tube migration; increased
risk of bacterial contamination; tube
obstruction; pneumothorax
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Costs more than oral diets (not necessarily)
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Less “palatable/normal”: patient/family
resistance
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Labor-intensive assessment, administration,
tube patency and site care, monitoring
Enteral Formulas
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Liquid diets intended for oral use or for
tube feeding
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Ready-to-use or powdered form
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Designed to meet variety of medical and
nutrition needs
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Can be used alone or given with foods
Formula Selection
The suitability of a feeding formula should be
evaluated based on
 Functional status of GI tract

Physical characteristics of formula (osmolality,
fiber content, caloric density, viscosity)
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Macronutrient ratios
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Digestion and absorption capability of patient
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Specific metabolic needs
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Contribution of the feeding to fluid and electrolyte
needs or restriction
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Cost effectiveness
Enteral Formulas
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Determine best choice by medical and
nutrition assessment
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Meet specific nutrition needs
Enteral Formulas
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Complete formulas:
– Enteral formulas designed to supply all
needed nutrients when given in sufficient
volume
– May also be used in smaller quantities to
supplement regular diets
Enteral Formula Categories
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Polymeric
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Monomeric
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Fiber-containing
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Disease-specific
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Rehydration
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Modular
Enteral Formula Categories
Polymeric
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Whole protein nitrogen source
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For use in patients with normal or near
normal GI function
– Protein isolate formulas
– Protein that has been separated from a food (casein
from milk, albumin from egg)
– Blenderized formulas
• May contain pureed meat, vegetables, fruits,
milk, starches with v/m added
• Made at home or purchased commercially
Enteral Formula Categories
Polymeric
Enteral Formula Categories
Monomeric
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Elemental/hydrolyzed
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Predigested nutrients
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Free amino acids and/or short peptide
chains
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Has low fat content or high percentage of
MCT, LCT, structured lipids
Enteral Formula Categories
Monomeric
Enteral Formula Categories
Monomeric
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Use in patients with compromised
digestive and/or absorptive capacity
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More expensive than standard formulas

Tend to be more hyperosmolar because of
small particle size
Enteral Formula Categories
Fiber-Containing
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Fiber-containing: containing a source of
fiber; reportedly beneficial for
prevention/treatment of altered bowel
function in enterally fed patients
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Soy polysaccharide is the most common
fiber additive in enteral feedings;
effectiveness in treating diarrhea in
tubefed patients unproven
ASPEN. The science and practice of nutrition support. A casebased core curriculum. 2001; 148
Enteral Formula Categories
Fiber-Containing

Soluble fiber (guar gum, oat fiber, pectin) may
exert trophic effect on colonic mucosa and be
useful in normalizing bowel function

Most enteral feedings in amounts typically used
contain less than recommended fiber intake for
adults (20-35 g)

Patients with impaired gastric emptying should
not be fed fiber-containing formula into the
stomach
ASPEN. The science and practice of nutrition support.
A case-based core curriculum. 2001; 148
Enteral Formula Categories
Fiber-Containing
Enteral Formulas: Calorie Dense
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May be used in fluid-restricted or
volume-sensitive patients
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Useful for nocturnal feedings where
nutrition must be delivered over brief
time span
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Calorie density ranges from 1.3 to 2
kcals/ml

Monitor fluid/hydration status
Enteral Formulas: Calorie Dense
Enteral Formula Categories
Disease Specific
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Designed for patients with specific
disease states.
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Available for patients with respiratory
disease, ARDS, diabetes, renal failure,
hepatic failure, and immune compromise.
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Well-designed clinical trials may or may
not be available (mostly not)
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Many of the trials have been done with
formula “cocktails,” making it difficult to
identify the operative variable
Enteral Formula Categories
Disease Specific
Enteral Formula Categories
Disease Specific

Pharmaceutical effects are claimed for
many specialty enteral formulas (reduced
LOS, reduced infections, reduced time on
the ventilator)
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Mfrs are charging pharmaceutical prices
(8-10 times more expensive than
standard)
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Enteral formulas are classed as medical
foods, not drugs and are regulated
differently
Enteral Formula Categories
Disease Specific
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The FDA does not evaluate adult medical
foods before they go on the market
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The government does not require that
mfrs prove that formulas are safe and
effective or that claims are valid
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FDA requires that formula mfrs use good
manufacturing practices and that products
are accurately labeled
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It is up to the clinician to evaluate the
evidence that supports the claims
regarding medical foods
Considerations in Evaluating
Specialized Enteral Formulas
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Is the nutrient profile appropriate based
on the known metabolic needs and
nutrient requirements of the condition
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Are there prospective double-blind RCTs
to support claims (not case reports)
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Data obtained using animal models may
have limited application to humans
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Product-specific research applies to that
product only
Enteral Formulas
Evaluating the Research
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Research cannot always be generalized to
a different population (studies in burn
patients to trauma pts)
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Were the endpoints clinically significant
(a biochemical marker only or important
clinical outcome such as wound healing)?
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Who funded the study?
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Has the work been replicated?
Disease Specific Formulas
Diabetic
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Amount and type of CHO modified to
reduce blood glucose response
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Increased fat content (may have increased
monounsaturated fats)
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Results of studies using these formulas
have been mixed
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Most standard enteral formulas fall
within American Diabetes Association
guidelines for macronutrient mix
Disease Specific Formulas
Diabetic
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Blood glucose control in acute care is
often affected by illness, infection, other
issues
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Patients on enteral feedings generally
receive a more consistent CHO intake
than persons on oral diets
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May be worth trying diabetes formulas in
patients who have failed to achieve good
blood glucose control on standard
formulas
Disease Specific Formulas: Diabetic
Disease Specific Formulas
Hepatic
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Generally have reduced aromatic amino acids
and increased branched chain amino acids
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More expensive than standard products
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Often lower in protein than standard formulas
(may be too low for most liver patients)
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Research using these products has been
inconclusive
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Standard (high protein) products are generally
appropriate for patients with liver disease
Disease Specific Formulas
Renal
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Originally developed in an effort to delay
the need for dialysis as long as possible
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Typically are calorie dense (2.0 kcal/cc)
products with relatively low protein
levels and modified electrolytes
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Generally too low in protein for dialyzed
patients and acutely ill patients
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May be useful for short term use as
supplement or calorie source in predialysis chronic renal failure patients
Disease-Specific Formulas Renal
Novasource Renal
Disease Specific Formulas
Immune-Enhancing
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Have added “immune-enhancing”
nutrients (arginine, glutamine, omega-3
fatty acids, nucleotides)
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Results of research have been mixed
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Multiplicity of active ingredients makes it
difficult to control variables
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Meta-analysis suggests that they might be
most beneficial in surgical patients
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Some evidence of harm in septic patients
Immune-Enhancing EN in Critical
Care: ADA Evidence-Based Guidelines
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R.3 Immune-enhancing EN is not
recommended for routine use in critically ill
patients in the ICU.
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Immune-enhancing EN is not associated with
reduced infectious complications, LOS, reduced
cost of medical care, days on mechanical
ventilation or mortality in moderately to less
severely ill ICU patients.
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Their use may be associated with increased
mortality in severely ill ICU patients, although
adequately-powered trials evaluating this have
not been conducted.
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Strength: Fair; imperative
Immune-Enhancing EN in Critical
Care: ADA Evidence-Based Guidelines
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For the trauma patient, it is not
recommended to routinely use immuneenhancing EN, as its use is not associated
with reduced mortality, reduced LOS,
reduced infectious complications or fewer
days on mechanical ventilation.
Source: ADA EAL Evidence-Based Guidelines,
accessed 8/07
Immune-Enhancing Formulas
Disease-Specific Formula
Pulmonary
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Contain higher percentage of total
calories from fat to reduce respiratory
quotient and make it easier to wean from
respirator
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However, total calorie intake has more
impact on respiratory function than
formula composition
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There is a lack of clinical trials
demonstrating a clear benefit
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High fat gastric feedings may cause
delayed emptying in critically ill patients
Disease-Specific Formulas:
Pulmonary
Enteral Formula Categories
Rehydration and Modular
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Rehydration: for patients requiring
optimal ratio of carbohydrate to
electrolytes to facilitate fluid and
electrolyte absorption, rehydration
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Modular: provides protein, fat, or
carbohydrate as single nutrients or
modular mixtures to allow adjustment of
macronutrient mix. May also contribute
to renal solute load, osmolality
Enteral Formula Categories
Modular
Enteral Formula Nutrient Sources
Carbohydrate
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CHO content ranges from 40-90% of total
calories
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Typically some combination of hydrolyzed
cornstarch, maltodextrins, corn syrup solids,
sucrose
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FOS: fructooligosaccharides; poorly absorbed
in the small intestine, fermented in the large
intestine; may promote growth of healthy
bacteria
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Fiber: soy polysaccharide (most common) guar
gum, oat fiber, pectin
Enteral Formula Nutrient Sources
Lipids
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Fat provides isotonic, concentrated
energy source
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Corn and soybean oil common
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Also safflower, canola, fish oil
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May include MCTs; more easily digested
and absorbed
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Fat content ranges from <10% to >50%
of calories
ASPEN. The science and practice of nutrition support. A casebased core curriculum. 2001; 148
Enteral Formulas Nutrient Sources
Protein
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Whole protein, hydrolyzed protein, free
amino acids
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Casein, soy protein, lactalbumin, whey,
egg white albumin
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Small peptides absorbed as efficiently as
free amino acids
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Free amino acids are more hyperosmolar
Enteral Formulas Nutrient Sources
Protein
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Arginine: conditionally essential amino
acid with immune-enhancing properties.
Research suggests some benefit in wound
healing (rat studies and biochemical
changes.) Recent research suggests may
be harmful in septic patients
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Glutamine: may enhance small intestine
growth and repair; however, available
research done with parenteral glutamine;
enteral delivery not well studied
Enteral Formulas: Nutrient Sources
Protein
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Branched-Chain Amino Acids: evaluated in
critical care and liver failure patients in the 70s
and 80s
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Thought to prevent or treat hepatic
encephalopathy and prevent muscle catabolism
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Studies using BCAA have been inconclusive
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Effectiveness of therapy cannot be evaluated
based on current research
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BCAA sometimes recommended for refactory
encephalopathy
Establishing an Enteral Formulary
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Many health care organizations find it
cost-effective to establish an enteral
formulary based on clinical effectiveness
and cost
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The health care organization or
management company may purchase
from one company or several
Establishing an Enteral Formulary
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Evaluate common diagnoses of patients
on enteral formulas and the formulas
most often used in the past year
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Identify categories of formulas that fill a
need, such as standard 1 kcal/cc formula;
standard 1 kcal/cc high protein formula;
calorie dense formula (1.5 or 2.0
calories/cc); fiber-containing,
monomeric, etc.
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Write generic specifications for each
product category
Establishing an Enteral Formulary
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Identify commercially available products
that fit into each category
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Where several formulas fit, choose based
on cost, service, available packaging
(closed vs open system)
Open vs Closed System
Open System
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Product is decanted into a
feeding bag
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Allows modulars such as
protein and fiber to be
added to feeding
formulas
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Less waste in unstable
patients (maybe)
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Shortens hang time
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Increases nursing time
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Increased risk of
contamination
Closed System or Ready to Hang
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Containers sterile until
spiked for hanging
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Can be used for
continuous or bolus
delivery
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No flexibility in formula
additives
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Less nursing time
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Increases safe hang time
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Less risk of
contamination
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More expensive than
canned formula
Closed vs Open System
Open System
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Hang time 8 hours for
decanted formula; 4
hours for formula
mixtures
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Feeding bag and
tubing should be
rinsed each time
formula replenished
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Contaminated
feedings are
associated with pt
morbidity
Closed System
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Hang time 24-48
hours based on mfr
recommendations
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Y port can be used to
deliver additional
fluid and modulars
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May result in less
formula waste as
open system formula
should be discarded p
8 hours
Closed vs Open System
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In a survey of nurses at MetroHealth, only 28%
were aware of the 8 hour hang time for open
system formulas written into nursing policy
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55% recommended adding new formula to old,
in violation of existing nursing protocol
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66% could state the 24 hang time for closed
system formulas
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The cost of wasted formula is minimal
compared to the cost of nursing time and risk of
illness in patients
Luther H, Barco K, Chima CS, Yowler CJ. Comparative study of two systems of
delivering supplemental protein with standardized tube feedings. J Burn Care Rehabil
2003;24:167-172.
Nursing Time Open vs Closed System
(MetroHealth)
Figure 1. Total daily nursing time protein bolus vs open
system
40
36.6
35
30
25
18.6
20
Minutes/day
15
10
5
0
Open System
Closed System/ Protein
Flush
N=5; P=.05
Luther H, Barco K, Chima CS, Yowler CJ. J Burn Care Rehabil 2003;24:167-172.