1. Introduction to Enteral Nutrition

2. Enteral Nutrition Nutrition delivered via the gut
Includes oral feedings and tube feedings

3. 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.

4. 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

5. Diagram of enteral tube placement.
Fig p. 468.

6. 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

7. 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.

8. Indications for Enteral Nutrition
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

9. Contraindications for EN
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

10. Contraindications for EN
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

11. Advantages - Enteral vs PN
Preserves gut integrity
Possibly decreases bacterial translocation
Preserves immunological function of gut
Reduces costs (EAL Grade II)
Fewer infectious complications in critically ill patients (EAL Grade I)
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

12. Advantages—Enteral Nutrition
Intake easily/accurately monitored
Provides nutrition when oral is not possible or adequate
Supplies readily available
Reduces risks associated with disease state

13. Disadvantages—Enteral Nutrition
GI, metabolic, and mechanical complications—tube migration; increased risk of bacterial contamination; tube obstruction; pneumothorax
Costs more than oral diets (not necessarily)
Less “palatable/normal”: patient/family resistance
Labor-intensive assessment, administration, tube patency and site care, monitoring

14. Enteral Formulas
Liquid diets intended for oral use or for tube feeding
Ready-to-use or powdered form
Designed to meet variety of medical and nutrition needs
Can be used alone or given with foods

15. 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)
Macronutrient ratios
Digestion and absorption capability of patient
Specific metabolic needs
Contribution of the feeding to fluid and electrolyte needs or restriction
Cost effectiveness

16. Enteral Formulas
Determine best choice by medical and nutrition assessment
Meet specific nutrition needs

17. Enteral Formulas 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

18. Enteral Formula Categories
Polymeric
Monomeric
Fiber-containing
Disease-specific
Rehydration
Modular

19. Enteral Formula Categories Polymeric
Whole protein nitrogen source
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

20. Enteral Formula Categories Polymeric

21. Enteral Formula Categories Monomeric
Elemental/hydrolyzed
Predigested nutrients
Free amino acids and/or short peptide chains
Has low fat content or high percentage of MCT, LCT, structured lipids

22. Enteral Formula Categories Monomeric

23. Enteral Formula Categories Monomeric
Use in patients with compromised digestive and/or absorptive capacity
More expensive than standard formulas
Tend to be more hyperosmolar because of small particle size

24. Enteral Formula Categories Fiber-Containing
Fiber-containing: containing a source of fiber; reportedly beneficial for prevention/treatment of altered bowel function in enterally fed patients
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 case-based core curriculum. 2001; 148

25. 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

26. Enteral Formula Categories Fiber-Containing

27. Enteral Formulas: Calorie Dense
May be used in fluid-restricted or volume-sensitive patients
Useful for nocturnal feedings where nutrition must be delivered over brief time span
Calorie density ranges from 1.3 to 2 kcals/ml
Monitor fluid/hydration status

28. Enteral Formulas: Calorie Dense

29. Enteral Formula Categories Disease Specific
Designed for patients with specific disease states.
Available for patients with respiratory disease, ARDS, diabetes, renal failure, hepatic failure, and immune compromise.
Well-designed clinical trials may or may not be available (mostly not)
Many of the trials have been done with formula “cocktails,” making it difficult to identify the operative variable

30. Enteral Formula Categories Disease Specific

31. Enteral Formula Categories Disease Specific
Pharmaceutical effects are claimed for many specialty enteral formulas (reduced LOS, reduced infections, reduced time on the ventilator)
Mfrs are charging pharmaceutical prices (8-10 times more expensive than standard)
Enteral formulas are classed as medical foods, not drugs and are regulated differently

32. Enteral Formula Categories Disease Specific
The FDA does not evaluate adult medical foods before they go on the market
The government does not require that mfrs prove that formulas are safe and effective or that claims are valid
FDA requires that formula mfrs use good manufacturing practices and that products are accurately labeled
It is up to the clinician to evaluate the evidence that supports the claims regarding medical foods

33. Considerations in Evaluating Specialized Enteral Formulas
Is the nutrient profile appropriate based on the known metabolic needs and nutrient requirements of the condition
Are there prospective double-blind RCTs to support claims (not case reports)
Data obtained using animal models may have limited application to humans
Product-specific research applies to that product only

34. Enteral Formulas Evaluating the Research
Research cannot always be generalized to a different population (studies in burn patients to trauma pts)
Were the endpoints clinically significant (a biochemical marker only or important clinical outcome such as wound healing)?
Who funded the study?
Has the work been replicated?

35. Disease Specific Formulas Diabetic
Amount and type of CHO modified to reduce blood glucose response
Increased fat content (may have increased monounsaturated fats)
Results of studies using these formulas have been mixed
Most standard enteral formulas fall within American Diabetes Association guidelines for macronutrient mix

36. Disease Specific Formulas Diabetic
Blood glucose control in acute care is often affected by illness, infection, other issues
Patients on enteral feedings generally receive a more consistent CHO intake than persons on oral diets
May be worth trying diabetes formulas in patients who have failed to achieve good blood glucose control on standard formulas

37. Disease Specific Formulas: Diabetic

38. Disease Specific Formulas Hepatic
Generally have reduced aromatic amino acids and increased branched chain amino acids
More expensive than standard products
Often lower in protein than standard formulas (may be too low for most liver patients)
Research using these products has been inconclusive
Standard (high protein) products are generally appropriate for patients with liver disease

39. Disease Specific Formulas Renal
Originally developed in an effort to delay the need for dialysis as long as possible
Typically are calorie dense (2.0 kcal/cc) products with relatively low protein levels and modified electrolytes
Generally too low in protein for dialyzed patients and acutely ill patients
May be useful for short term use as supplement or calorie source in pre- dialysis chronic renal failure patients

40. Disease-Specific Formulas Renal
Novasource Renal

41. Disease Specific Formulas Immune-Enhancing
Have added “immune-enhancing” nutrients (arginine, glutamine, omega-3 fatty acids, nucleotides)
Results of research have been mixed
Multiplicity of active ingredients makes it difficult to control variables
Meta-analysis suggests that they might be most beneficial in surgical patients
Some evidence of harm in septic patients

42. Immune-Enhancing EN in Critical Care: ADA Evidence-Based Guidelines
R.3 Immune-enhancing EN is not recommended for routine use in critically ill patients in the ICU.
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.
Their use may be associated with increased mortality in severely ill ICU patients, although adequately-powered trials evaluating this have not been conducted.
Strength: Fair; imperative

43. Immune-Enhancing EN in Critical Care: ADA Evidence-Based Guidelines
For the trauma patient, it is not recommended to routinely use immune- enhancing 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

44. Immune-Enhancing Formulas

45. Disease-Specific Formula Pulmonary
Contain higher percentage of total calories from fat to reduce respiratory quotient and make it easier to wean from respirator
However, total calorie intake has more impact on respiratory function than formula composition
There is a lack of clinical trials demonstrating a clear benefit
High fat gastric feedings may cause delayed emptying in critically ill patients

46. Disease-Specific Formulas: Pulmonary

47. Enteral Formula Categories Rehydration and Modular
Rehydration: for patients requiring optimal ratio of carbohydrate to electrolytes to facilitate fluid and electrolyte absorption, rehydration
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

48. Enteral Formula Categories Modular

49. Enteral Formula Nutrient Sources Carbohydrate
CHO content ranges from 40-90% of total calories
Typically some combination of hydrolyzed cornstarch, maltodextrins, corn syrup solids, sucrose
FOS: fructooligosaccharides; poorly absorbed in the small intestine, fermented in the large intestine; may promote growth of healthy bacteria
Fiber: soy polysaccharide (most common) guar gum, oat fiber, pectin

50. Enteral Formula Nutrient Sources Lipids
Fat provides isotonic, concentrated energy source
Corn and soybean oil common
Also safflower, canola, fish oil
May include MCTs; more easily digested and absorbed
Fat content ranges from <10% to >50% of calories
ASPEN. The science and practice of nutrition support. A case-based core curriculum. 2001; 148

51. Enteral Formulas Nutrient Sources Protein
Whole protein, hydrolyzed protein, free amino acids
Casein, soy protein, lactalbumin, whey, egg white albumin
Small peptides absorbed as efficiently as free amino acids
Free amino acids are more hyperosmolar

52. Enteral Formulas Nutrient Sources Protein
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
Glutamine: may enhance small intestine growth and repair; however, available research done with parenteral glutamine; enteral delivery not well studied

53. Enteral Formulas: Nutrient Sources Protein
Branched-Chain Amino Acids: evaluated in critical care and liver failure patients in the 70s and 80s
Thought to prevent or treat hepatic encephalopathy and prevent muscle catabolism
Studies using BCAA have been inconclusive
Effectiveness of therapy cannot be evaluated based on current research
BCAA sometimes recommended for refactory encephalopathy

54. Establishing an Enteral Formulary
Many health care organizations find it cost-effective to establish an enteral formulary based on clinical effectiveness and cost
The health care organization or management company may purchase from one company or several

55. Establishing an Enteral Formulary
Evaluate common diagnoses of patients on enteral formulas and the formulas most often used in the past year
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.
Write generic specifications for each product category

56. Establishing an Enteral Formulary
Identify commercially available products that fit into each category
Where several formulas fit, choose based on cost, service, available packaging (closed vs open system)

57. Open vs Closed System

58. Open System Product is decanted into a feeding bag
Allows modulars such as protein and fiber to be added to feeding formulas
Less waste in unstable patients (maybe)
Shortens hang time
Increases nursing time
Increased risk of contamination

59. Closed System or Ready to Hang
Containers sterile until spiked for hanging
Can be used for continuous or bolus delivery
No flexibility in formula additives
Less nursing time
Increases safe hang time
Less risk of contamination
More expensive than canned formula

60. Closed vs Open System Open System
Hang time 8 hours for decanted formula; 4 hours for formula mixtures
Feeding bag and tubing should be rinsed each time formula replenished
Contaminated feedings are associated with pt morbidity
Closed System
Hang time hours based on mfr recommendations
Y port can be used to deliver additional fluid and modulars
May result in less formula waste as open system formula should be discarded p 8 hours

61. Closed vs Open System
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
55% recommended adding new formula to old, in violation of existing nursing protocol
66% could state the 24 hang time for closed system formulas
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:

62. Nursing Time Open vs Closed System (MetroHealth)
Luther H, Barco K, Chima CS, Yowler CJ. J Burn Care Rehabil 2003;24: