What are the nutritional recommendations for patients undergoing Continuous Renal Replacement Therapy (CRRT) to minimize malnutrition and improve clinical outcomes?

Nutritional Recommendations for Patients on CRRT

Patients undergoing Continuous Renal Replacement Therapy (CRRT) require specific nutritional interventions to prevent malnutrition and improve clinical outcomes, including hypocaloric feeding initially followed by progressive increases in energy and protein intake, with careful monitoring of micronutrient losses. 1

Energy Requirements

• Initial phase (first 3 days):

  • Provide hypocaloric nutrition not exceeding 70% of energy expenditure 1
  • Avoid early full enteral or parenteral nutrition to prevent overfeeding 1

• After day 3:

  • Progressively increase caloric delivery to 80-100% of measured energy expenditure 1
  • Target range: 25-35 kcal/kg/day 2
  • Energy distribution: 60-70% from carbohydrates, 30-40% from lipids 2

• Measurement methods:

  • Indirect calorimetry is preferred when available 1
  • Repeat measurements whenever clinical condition changes 1
  • Recent evidence suggests indirect calorimetry during CRRT is valid despite previous concerns about CO2 removal in the effluent 1

Protein Requirements

• Target protein intake: 1.5-2.5 g/kg/day 2, 3

  • Higher protein intake (≥2.0 g/kg/day) is associated with improved nitrogen balance and survival 3
  • Protein requirements are higher than in non-CRRT patients due to significant losses in the effluent 1

• Clinical impact: Positive nitrogen balance is directly associated with improved ICU and hospital survival 3

  • For every 1 g/day increase in nitrogen balance, probability of survival increases by 21% 3

Feeding Route Considerations

• Enteral nutrition (EN):

  • Preferred route when possible 1
  • Associated with better outcomes compared to parenteral nutrition 1
  • CRRT may help prevent intestinal edema and maintain gastrointestinal function 4

• Parenteral nutrition (PN):

  • Use when EN is not tolerated or insufficient to meet targets 1
  • Consider supplementing EN with PN if targets cannot be achieved enterally 3

• Intradialytic parenteral nutrition (IDPN):

  • Reserved for malnourished patients who fail to respond to or cannot tolerate oral nutritional supplements or EN 1

Micronutrient Considerations

• Water-soluble vitamins:

  • Significant losses occur during CRRT, especially thiamine and folate 5
  • Daily folate losses of approximately 265 mg/day reported 1
  • Vitamin C supplementation should not exceed 30-50 mg/day to prevent secondary oxalosis 1

• Trace elements:

  • Selenium and thiamine requirements increase during prolonged CRRT 1
  • Supplement at least double the recommended dietary allowances 1
  • Additional magnesium and calcium may be needed 1
  • Zinc supplementation generally not required 1

Monitoring and Assessment

• Regular nutritional assessment:

  • Use a combination of screening tools, anthropometry, and laboratory parameters 6
  • Monitor for malnutrition development, which occurs in up to 84% of critically ill patients 7

• Nitrogen balance:

  • Measure periodically to assess catabolism and evaluate protein intake 6
  • More likely to achieve positive nitrogen balance with protein intake >2 g/kg/day 3

Common Pitfalls and Considerations

• Delayed nutrition initiation:

  • Up to 28.6% of ICU patients have enteral feeding initiated >48 hours after admission 7
  • Early nutrition initiation is critical for preventing malnutrition

• Underfeeding:

  • Up to 87.4% of patients fail to receive at least 80% of protein targets 7
  • Underfeeding is associated with increased mortality in both ICU and hospital settings 7

• Overfeeding risks:

  • Hyperglycemia and hypertriglyceridemia 1
  • Positive fluid balance complications 1
  • Increased length of stay, ventilation duration, and infection rates 1

• Formula selection:

  • Standard formulas are adequate for most patients 1
  • Consider renal-specific formulas when electrolyte derangements are present 1

By following these evidence-based nutritional recommendations, clinicians can optimize the care of critically ill patients undergoing CRRT, potentially improving survival outcomes and quality of life.