Fluids, Electrolytes & Nutrition: Enteral Nutrition

Initiation

• Early Initiation (Within 48 Hours) Generally Preferred
• Preferred Over TPN if Able
• Consider PEG Tube Placement if Not Eating for > 4 Weeks

Contraindications

• Hemodynamic Instability on Vasopressor Support (Risk for Intestinal Ischemia)
  • May Still Consider Trophic Tube Feeds (10-30 cc/hr) to Prevent Mucosal Atrophy
  • *Effect is Debated
• Bowel Ischemia
• Major Upper GI Bleeding
• Bowel Obstruction
• Prolonged Ileus
• Intractable Vomiting
• *Fresh Anastomosis is Not a Contraindication & Early Enteral Nutrition Actually Improves Outcomes

Benefits

• Early Enteral Feeding Increases Survival in Sepsis & Pancreatitis
• IBD Patients Have Decreased Risk of Infectious Complications
• Comparison to TPN:
  • Avoids Bacterial Translocation (Bacteria Within Gut Lumen Traverse Intestinal Wall & Colonize Mesenteric Lymph Nodes)
  • Avoids TPN Complications

Access Site

• Gastric
  • Generally Preferred – Easier to Place & Better Approximation of Normal Physiology
  • Contraindications:
    • Nasogastric Tube Output > 600 cc/Day
    • History of Aspiration
    • Lack of Adequate Airway Protection
    • Severe Pulmonary Dysfunction
    • Recent Regurgitation
    • Unable to Maintain 30-Degree Reverse Trendelenburg Position
• Postpyloric/Jejunal
  • Preferred if Risk of Aspiration (Delayed Gastric Emptying or Severe GERD)
  • Lower Rates of Pneumonia
  • No Difference in Mortality or Complications

Feeding Administration

• Bolus
  • Large Amounts Over Short Period (≤ 5 Minutes)
  • Use Only for Gastric Feeding, Not Postpyloric (Will Not Tolerate Such a Large Volume)
  • Most Likely to Cause GI Side Effects
• Intermittent
  • Can Use for Either Gastric or Postpyloric Feedings
• Continuous
  • Can Use for Either Gastric or Postpyloric Feedings
  • Usually the Best Tolerated Method, Especially in the Postoperative Period or ICU

Management

• Gastric Residuals:
  • Typically Checked Every 4-8 Hours Once Tube Feeds are Initiated
  • Hold Enteral Feeds if ≥ 200-250 cc (Some Consider 400-500 cc)
  • Consider Starting Reglan or Erythromycin with High Residuals
  • *Benefit of Evaluation is Not Definitive & Some Argue Against Using Gastric Residual Volumes at All
• Clamp Trial:
  • Generally Performed when Considering Removal of a Nasogastric Tube
    • Used if Tube Has Been Set to Suction (Not Necessary if Being Used for Feeding)
  • Clamp Tube (Take Off Suction) for 4 Hours & Then Check the Residuals
  • Failure Generally Defined as Residuals ≥ 125 cc (Exact Amount Poorly Defined)
  • *Benefit is Questioned & Some Recommend Removal When Clinically Ready without a Clamp Trial

Complications

• Aspiration
  • Higher Risk with High Gastric Residuals
• Diarrhea
  • Treatment: Decrease Rate with an Isotonic Formula & Fiber Supplementation
• Metabolic Deficiencies
  • Micronutrient Deficiencies
  • Refeeding Syndrome
  • Hyperglycemia
• Intestinal Ischemia
  • Higher Risk if On Vasopressors
  • *Effect is Debated