Specialized nutrition support

Specialized nutrition support (SNS) is required when oral intake is either limited or not possible for a prolonged period of time. Common indications for SNS include patients in critical care, those with dysphagia, unconscious patients who cannot be fed, severely malnourished patients, and those with intestinal malabsorption. The two forms of SNS are enteral nutrition and parenteral nutrition. Enteral feeding is always preferred whenever possible, but parenteral feeding may be instituted if the patient has a nonfunctional GI tract (e.g., gastroschisis, short bowel syndromes), and/or if enteral feeding is contraindicated. Patients who are on SNS may develop several complications related to feeding tubes or intravenous catheters, as well as additional metabolic complications such as electrolyte imbalances, hyperglycemia, refeeding syndrome, gallstone disease, and nonalcoholic fatty liver disease.

• Dysphagia; (e.g., post-stroke state; , multiple sclerosis, esophageal carcinoma)
• Patients with a low GCS who cannot be fed
• Difficulty with oral intake in the early postoperative state
• Severe anorexia (e.g., terminally ill cancer patients, anorexia nervosa)
• Severe malnutrition
• Critically-ill patients
• Intestinal malabsorption

• First-line: enteral feeding
  • Advantages
    • Easier to perform
    • Metabolic complications occur less often
    • Intestinal motility is stimulated, preventing mucosal atrophy
    • Lower risk of blood stream infection
• Second-line: parenteral feeding

The following principle applies in most situations: oral before enteral, enteral before parenteral!

• Definition: administration of nutrients directly into the stomach, duodenum, or jejunum with the help of feeding tubes
• Contraindications
  • Mechanical ileus, bowel obstruction
  • Acute abdomen (e.g., severe pancreatitis, peritonitis)
  • Upper GI bleeding
  • Mucositis
  • Severe substrate malabsorption
  • Congenital GI anomalies
  • High-output fistulas
  • Nonfunctional GI tract (e.g., gastroschisis, short bowel syndromes)
• Routes
  • Short-term: nasogastric tube
  • Long-term (> 2–3 weeks):
    • Gastrostomy tube: gastric feeding tube inserted endoscopically through a small incision through the abdomen into the stomach or
    • Jejunostomy tube: feeding tube inserted through a small incision through the abdomen into the jejunum to bypass the distal small bowel and/or colon
• Complications
  • Feeding-tube-related:
    • Blockage of the feeding tube
    • Nasogastric tube:
      • Accidental placement of the tube inside the trachea
      • Injury to, or perforation of the stomach wall
    • Gastrostomy or jejunostomy:
      • Peristomal infection
      • High-output fistulas
  • Diarrhea
  • Gastroesophageal reflux
  • Metabolic complications of specialized nutrition support

• Definition: intravenous administration of nutrients that bypasses the gastrointestinal tract
  • Total parenteral nutrition: provision of all nutritional requirements intravenously without using the gastrointestinal tract
• Contraindications
  • Enteral nutrition is feasible
  • Serum hyperosmolality
  • Severe hyperglycemia
  • Severe electrolyte abnormalities
  • Volume overload
• Routes
  • Parenteral nutrition is required for < 2 weeks: peripheral venous line, or peripherally inserted central catheter
  • Parenteral nutrition is required for > 2 weeks: tunneled central venous catheter or a port
• Complications
  • Venous catheter-related:
    • Catheter displacement
    • Thrombosis and/or embolism
    • Catheter-related blood stream infection
  • Fluid overload
  • Metabolic complications of specialized nutrition support

• Severe electrolyte imbalances (e.g., hypocalcemia, hypomagnesemia, hypophosphatemia)
• Hyperglycemia
• Refeeding syndrome
• Hyperlipidemia
• Acalculous cholecystitis
• Gallstone disease
• Non-alcoholic fatty liver disease
• Renal damage
• Bone demineralization

Metabolic complications are more common with parenteral nutrition than enteral nutrition!