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Enteral Nutrition

Soibhan Kelley

Indications for enteral feeding

  • Patients with high nutritional risk who are unable to maintain their own intake
    • Guidelines recommend calculating nutritional risk based on validated scoring tool (ex: Malnutrition Screening Tool). This is usually completed by the nutrition team
    • Recognize 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 due to medical illness or surgery
  • Patients with low nutritional risk may not need enteral feeding if it is anticipated they will resume intake in 5-7 days
  • Critically ill patients: goal is early initiation of tube feeding (within 48 hours)

Contraindications to enteral nutrition

  • Bowel obstruction or severe ileus
  • Ischemic bowel
  • Acute peritonitis
  • Major gastrointestinal bleeding
  • Intractable vomiting
  • Significant hemodynamic instability
    • Patients who are not adequately volume resuscitated and have significant hemodynamic instability (i.e., have high pressor requirements) are thought to be at increased risk for bowel ischemia
      • Pressors in general are not a contraindication to tube feeds. Ok to start once pressors are down-trending or at a stable level

Initiating tube feeds

  • Enteral access

    • 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. RD will calculation caloric and protein needs to determine goal rate and formulation
    • OK to start tube feeds prior to recommendations and adjust later, especially if recommendations will be delayed. It only takes a simple calculation to make a reasonable tube feeding plan

      • Use weight-based dosing for calorie requirements
        • Use 25-30 cal/kg (use ideal body weight for most patients, use actual weight for underweight patient) to estimate daily needs
      • Most common formula used at VUMC is Nutren 1.5 (1.5 cal/ml) or Novasource renal if significant renal impairment (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 every 4 hours and monitor Na trends. May need more if already with a large fluid deficit (ex: hypernatremia) or if high volume losses
        • May use clinical calculators as below
    • 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 that gives you rate per hour for different weights and formula types
        • 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

      • Advance quickly if no concern for refeeding syndrome (ex: increase by 10cc/hr q6h)
      • If risk for refeeding syndrome or other issues with tolerability, typically advance more slowly over several days

Potential Complications

  • Aspiration

    • Recommendation to keep head of bed elevated at 30 to 45 degrees (low quality, mixed evidence). Consider risks of this positioning (ex: 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