Enteral Nutrition

Christine Hamilton

Indications for enteral feeding

  • Patients with high nutrition risk with inability to tolerate PO intake
  • Patients whose intake does not support their metabolic demands.
    • Guidelines recommend calculating nutritional risk based on validated scoring tool (e.g. Malnutrition Universal Screening Tool). This is usually completed by the nutrition team.
  • Who would benefit from nutrition consult to assist with risk determination?
    • Patients with >5% weight loss in past 1-3 months or decreased oral intake coupled with increased metabolic demands (i.e. medical illness or surgery)
  • Critically ill patients: goal is early initiation of tube feeding (within 48 hours)

Contraindications to enteral nutrition

  • Patients at low nutritional risk (you anticipate improved intake within 5-7 days)
  • Bowel obstruction or severe ileus
  • Ischemic bowel
  • Acute peritonitis
  • Major gastrointestinal bleeding o Intractable vomiting
  • Significant hemodynamic instability
  • Patients who are not adequately volume resuscitated and have significant hemodynamic instability (e.g. high pressor requirements) are at increased risk for bowel ischemia.
    • Pressors in general are not a contraindication to tube feeds. Okay to start once pressors are down-trending or at a stable level.

Obtaining enteral access

  • Typically place nasogastric or orogastric feeding tube in acute setting. See “Procedures” section for tips on placement.
    • For most patients, enteral feeding is safe with gastric tube placement.
    • Consider post-pyloric placement for patients with high aspiration risk, impaired gastric motility, or patients who have demonstrated intolerance with gastric feeding.
  • Consider percutaneous endoscopic gastrostomy (PEG) tube placement if anticipate enteral nutrition >4 weeks

Choice of formula and rate: Place Nutrition consult

  • Okay to start tube feeds prior to recommendations and adjust later, especially if recommendations will be delayed.
  • 25-30 cal/kg (use ideal body weight for most patients, use actual weight for underweight patient) to estimate daily needs.
    • Most common formulas at VUMC: Nutren 1.5 (1.5 cal/ml), Novasource renal (2 cal/ml)
    • Patients may need additional free water (most tube feed formulas are comprised of 80-85% water but varies with type). Typically dose as bolus of free water every 4-6 hours.
    • May empirically try 250cc free water q4h and monitor Na trends. May need more if already with a large fluid deficit (e.g. hypernatremia) or if high volume losses.
  • Calculate hourly rate based on daily calorie need and formula calorie density
    • Ex: Patient with IBW of 70Kg will need estimated 1,750 calories per day (70 x 25 cal/kg. If using Nutren 1.5, this will equal 1,167 ml per day (1,750 divided by 1.5 calories per ml). This would equal a goal rate of about 50ml per hour (rounded up) of Nutren 1.5
    • Resources for quick calculations:
      • Search for “tube feed cheat sheet” on google and will find reference tables on EMCrit.org that gives you rate per hour for different weights and formula types
      • Clincalc.com also has a useful enteral nutrition calculator
  • Start initially at a low rate (such as 10 mL/hr) to assess tolerability and advance to goal
    • If no concern for refeeding syndrome, typically increase by 10cc/hr q6h
    • If risk for refeeding syndrome or other issues with tolerability, typically advance more slowly over several days

Condensing to bolus feeds

  • Typically begin condensing by providing 4 bolus meals per day run over 2 hours, then shorten run time to ~30 minutes or by gravity
  • NOTE: J-tube cannot be bolused; if condensing feeds for patients receiving enteral nutrition via J-tube, typically you can increase the rate to run all nutrition over 10-14 hours to allow the patient freedom from the pump

Potential Complications

  • Aspiration
    • Recommendation to keep head of bed elevated at 30 to 45 degrees (low quality, mixed evidence). Consider risks of this positioning (e.g. formation of pressure ulcers)
    • Consider post-pyloric placement if issues with aspiration (low quality, mixed evidence)
  • Diarrhea or constipation
    • Consider wheat dextrin fiber supplement (low quality evidence) but discontinue if not associated with clinical improvement. Avoid less soluble fibers such as psyllium due to risk of clogging tube. Avoid in patients with reduced GI motility due to rare risk of bezoar formation.
  • Hyperglycemia: See Endocrine section for management
  • Refeeding syndrome
    • Monitor q8 hour Mg, phos, K in high-risk patients (underweight, recent weight loss, prolonged poor intake) and advance to goal slowly
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