Definitions/Types

• Total Parenteral Nutrition (TPN): IV Nutrition Given Through a Central Venous Catheter
• Peripheral Parenteral Nutrition (PPN): IV Nutrition Given Through a Peripheral Venous Catheter
  • Lower Osmolarity but Still Hyperosmolar – Damaging to Vessels

Indications

• Anticipated NPO Status with Enteral Nutrition Contraindications for 7-10 Days
• May Consider Shorter Time Period if Previously Malnourished
• Consider Giving Preoperatively for Patients with Severe Malnutrition (> 15% Weight Loss)

Relative Indications

• Short Bowel Syndrome
• Complete Bowel Obstruction
• Radiation Enteritis
• Unable to Obtain Enteral Access
• Unable to Tolerate Sufficient Enteral Nutrition
• Severe Pancreatitis and Not Tolerating Enteral Feeding
• High Output Enterocutaneous Fistula (ECF)
• Inflammatory Bowel Disease (IBD) Not Responding to Medical Therapy

Contraindications

• Hyperosmolarity
• Severe Hyperglycemia
• Severe Electrolyte Abnormalities
• Volume Overload
• Inadequate IV Access – Hyperosmolarity is Damaging to Peripheral Veins
• Functional GI Tract
• Inadequate Attempts to Feed Enterally
• Poor Prognosis that Does Not Warrant Aggressive Nutritional Support

Nutritional Contents

• Dextrose/Glucose – The Nutritional Basis of TPN
• Amino Acids (Includes Most Amino Acids – Except Arginine and Glutamine)
• Electrolytes
• Vitamins and Minerals
• Lipids are Not Included
  • Lipid Emulsion Must Be Given Separately but Generally Not Started within the First Week
• *Can Add Insulin to the Bag to Aid in Glucose Control

Calculations

• Multiple Guidelines Exist for Calculating TPN Contents
• Each of the Contents Can Be Adjusted to Specific Dosing Goals
• Dosing is Generally Done by Pharmacy and Falls Outside of the Scope of This Review

Complications

• Central Line Issues:
  • Pneumothorax
  • Venous Thromboembolism (VTE/DVT)
  • Bloodstream Infection
• Liver Dysfunction: Stasis, Sludge, Stones, Fibrosis, and Cirrhosis
  • Overall Risk in Adults: 15-40%
  • Significantly Higher Risk in Infants (40-60%)
  • Incidence Increases with Time on TPN (55% After 2 Months, 72% After 6 Years)
• Metabolic Bone Disease
• Metabolic Deficiencies
  • Micronutrient Deficiencies
  • Refeeding Syndrome
  • Hyperglycemia – The Most Common Complication
• Hypoglycemia with Abrupt Cessation
  • Cessation Should Be Tapered if Diabetic (Tapering is Unnecessary if Otherwise)
• Bacterial Translocation – From Lack of Enteral Feeding Causing Mucosal Barrier Alteration