What are the guidelines for initiating refeeding parenteral nutrition (PN)?

Guidelines for Initiating Refeeding Parenteral Nutrition (PN)

When initiating parenteral nutrition in malnourished patients, start with reduced caloric intake of 15-20 kcal/kg/day for patients at risk of refeeding syndrome, and gradually increase over several days while closely monitoring electrolytes to prevent metabolic complications. 1, 2

Identifying Patients at Risk for Refeeding Syndrome

Patients at high risk for refeeding syndrome include:

• Severely malnourished patients (>10% weight loss in 3 months)
• Patients with little or no nutritional intake for >5 days
• History of alcohol abuse or chronic malnutrition
• Patients with severe acute pancreatitis
• Patients with chronic conditions (cirrhosis, cancer, chronic pancreatitis)
• Low baseline levels of phosphate, potassium, or magnesium

Initial PN Protocol for Refeeding

Day 1 Recommendations:

• Energy provision:

  • High-risk patients: 15-20 kcal/kg/day (non-protein) 1
  • Standard patients: 25 kcal/kg/day (non-protein) 1
  • Critical illness (acute phase): Reduce to lower ranges per weight (see below)

• Glucose administration:

  • Preterm newborns: 4-8 mg/kg/min (5.8-11.5 g/kg/day) 1
  • Term newborns: 2.5-5 mg/kg/min (3.6-7.2 g/kg/day) 1
  • Adults: Start with 2-3 g/kg/day and adjust based on glucose monitoring 1

• Protein/amino acids:

  • Standard: 1.2-1.5 g/kg/day 1
  • Acute liver failure: 0.8-1.2 g/kg/day 1

• Lipids:

  • 0.8-1.5 g/kg/day 1
  • Temporarily discontinue if triglycerides >12 mmol/L 1

Essential Preventive Measures:

1. Vitamin supplementation:

   • Administer thiamine (200-300 mg/day) before starting glucose infusion 1, 3
   • Include daily multivitamins and trace elements from day 1 1

2. Electrolyte monitoring and replacement:

   • Monitor phosphate, potassium, and magnesium daily for at least 7 days 1, 4
   • Proactively supplement electrolytes:
     • Potassium: ~2-4 mmol/kg/day
     • Phosphate: ~0.3-0.6 mmol/kg/day
     • Magnesium: ~0.2 mmol/kg/day (IV) or 0.4 mmol/kg/day (oral) 1

3. Fluid management:

   • Restrict fluid to maintenance requirements
   • Monitor for fluid overload, especially in patients with cardiac or renal issues 2

Progression Protocol

Days 2-4:

• Gradually increase calories by 25% every 24-48 hours if no signs of refeeding syndrome
• Target final caloric intake: 25-30 kcal/kg/day (standard) 1
• Continue daily monitoring of electrolytes, glucose, and fluid status

Specific Adjustments by Patient Population:

• Critically ill (SIRS/MODS): Maintain at 15-20 kcal/kg/day 1
• Cirrhotic patients: Provide energy to cover 1.3 × REE 1
• Acute liver failure: Provide energy to cover 1.3 × REE 1
• Pediatric patients: Follow age/weight-specific recommendations 1

Monitoring Requirements

• Daily monitoring (first week):

  • Serum phosphate, potassium, magnesium
  • Blood glucose (multiple times daily)
  • Fluid balance and weight
  • Cardiac monitoring in high-risk patients

• Additional monitoring:

  • Triglycerides (especially with lipid administration)
  • Liver function tests
  • Renal function

Tapering/Discontinuation Protocol

• Adults: Abrupt discontinuation is generally safe 2
• Children under 2 years and high-risk adults: Taper over 1-2 hours to prevent hypoglycemia 2
• Transition to enteral/oral feeding: Overlap periods of PN and enteral/oral feeding until adequate intake is established 1

Common Pitfalls to Avoid

1. Overfeeding: This is a major risk leading to metabolic complications including hyperglycemia, hyperlipidemia, and hepatic steatosis 1, 3

2. Inadequate electrolyte monitoring: Daily monitoring is essential in the first week, as 84% of patients may develop electrolyte abnormalities despite preventive measures 4

3. Failure to identify high-risk patients: Comprehensive nutritional assessment before initiating PN is crucial 4, 5

4. Inadequate thiamine supplementation: Must be given before glucose administration in malnourished patients to prevent Wernicke's encephalopathy 1

5. Rapid advancement of nutrition: Gradual progression over several days is essential for high-risk patients 1, 5

By following these guidelines, clinicians can safely initiate parenteral nutrition while minimizing the risk of refeeding syndrome and other metabolic complications.