Pvi / Pi / 25A10: With respect to enteral feeds

25A10: Exam Report

With respect to enteral feeds, outline the following;

  1. the dose (10% of marks).
  2. the composition and common ingredients; include in your answer the role of each ingredient, its form and caloric contribution if applicable (75% of marks).
  3. the adverse effects (complications related to feeding tubes are NOT required) (15% of marks).

Note. Paediatric OR adult descriptions acceptable.

62% of candidates passed this question.

  1. The dose of enteral feeds was generally well answered. Marks were awarded for the mention of methods used to estimate energy requirements (such as indirect calorimetry or the Harris- Benedict equation.
  2. The composition of enteral feeds should include the macronutrients (fat, CHO, protein), micronutrients and water and what form they are presented in. The quantities of each constituent and the contribution of each to the daily caloric goal was also required. Mention of alternate formulations such as soy-based feeds or elemental feeds in pancreatic disease scored additional marks.
  3. Adverse effects were well covered and included gastrointestinal, metabolic and long-term consequences. As noted, in the question, marks were not allocated for complications related to feeding tubes.

Pi / Pvi / 25A10: With respect to enteral feeds

Definition

Enteral Feeds = Nutrients delivered via a tube to the GIT as a mixture of protein, carbohydrates, vitamins and minerals.

a)

  • Dose = patient dependent & individualised (calculated) but generally:
    • 25kcal/Kg/day (max 35kcal/Kg/day)
    • 4g/Kg/day carbohydrate
    • 1.5g/Kg/day protein (max 2g/Kg/day)
    • 1g/Kg/day fat (max 2g/Kg/day)
    • 30ml/Kg/day H2O
  • Predicted by the Harris-Benedict equation
    • Multiple this by a stress factor
      • i.e. trauma/burns have increased requirements (higher protein needs).
  • Usually run at 40-80ml/hour
  • “Successful” enteral feeding is greater than or equal to 40ml/hour with 4H aspirates <250mL
  •  

b) the composition and common ingredients

Composition

  • 1kcal/mL to 2kcal/mL of solution, osmolality 300-600mOsm/Kg.
    • Usually Iso-osmolar to optimise absorption and prevent diarrhoea
  • Standard polymeric formulation
  • Small peptide formulation
  • Disease specific formulation (i.e. for pancreatitis) 
  • Generally, 1L

Protein

  • 10-15% of calories
    • 40-70g/L
    • As Casein

Carbohydrate

  • 50-60% of calories
  • 100-200g/L
  • As maltodextrin

Fat

  • 30-35% of calories
  • 30-50g/L
  • As sunflower oil, corn oil and canola oil

H2O

  • 80% water

Vitamins

  • Added in feed up to RDA
    • Fat Soluble:
      • ADEK
    • Water soluble:
      • Vitamin C
      • Thiamine
      • Riboflavin
      • Pyridoxine
      • Nicotinic acid
      • Vitamin B12
      • Folic acid

Minerals

  • Added in feed up to RDA
    • Na+ (2mmol/Kg/day)
    • K+ (1mmol/Kg/day)
    • Mg2+ (0.1mmol/Kg/day)
    • Phosphate (0.1mmol/Kg/day)

Trace elements

  • Added in feed to RDA
    • Chromium
    • Copper
    • Iodine
    • Manganese
    • Selenium
    • Zinc

c) the adverse effects

Side Effects

  • Aspiration at any point (less likely with post pyloric enteral feeding)

Acute

  • Refeeding syndrome
  • Electrolyte derangement
  • Hyperglycemia & insulin requirement
  • Hypertriglyceridemia
  • Diarrhoea
  • Nausea

Medium – Term

  • Micronutrient deficiencies
  • Over feeding
  • Under feeding
  • (as metabolic requirements change if requirements have not been recalibrated)

Long Term

  • Malnutrition (ie repeated delivery interruptions)
  • Obesity
  • Metabolic Syndrome
  • Sarcopenia
  • Altered oral aversion
  • Quality of life (long term feeding tubes)

Author: Alex Fagarasan