What are the kcal requirements for critically ill patients with Acute Kidney Injury (AKI)?

Caloric Requirements for Critically Ill Patients with AKI

For critically ill patients with Acute Kidney Injury (AKI), the recommended energy intake is 20-30 kcal/kg/day. 1

Energy Requirements Based on Phase of Critical Illness

Early Phase (First 72 hours)

• Hypocaloric nutrition (not exceeding 70% of energy expenditure) should be administered 1
• Avoid early full enteral or parenteral nutrition to prevent overfeeding 1
• This approach accounts for endogenous energy production (500-1400 kcal/day) during early critical illness 1

After Day 3

• Caloric delivery can be increased up to 80-100% of measured energy expenditure 1
• Progressive implementation to reach target calories by days 3-7 1

Methods to Determine Energy Requirements

1. Indirect Calorimetry (Gold Standard)

   • Most accurate method to assess energy expenditure 1
   • Can be performed during continuous renal replacement therapy (CRRT) 1
   • Wait at least 2 hours after intermittent dialysis for accurate measurements 1

2. When Indirect Calorimetry is Unavailable

   • Use 20-30 kcal/kg/day as a general starting point 1
   • If using predictive equations, target hypocaloric nutrition (below 70% of estimated needs) during the first week of ICU stay 1
   • Consider adjusted or ideal body weight for calculations in patients with fluid overload 1, 2

Special Considerations

Protein Requirements

• 0.8-1.0 g/kg/day for noncatabolic AKI patients without need for dialysis 1
• 1.0-1.5 g/kg/day for patients with AKI on renal replacement therapy (RRT) 1
• Up to 1.7 g/kg/day for patients on continuous renal replacement therapy (CRRT) and hypercatabolic patients 1

Energy from Renal Replacement Therapy

• Account for additional calories provided by:
  • Citrate (3 kcal/g) from anticoagulation
  • Glucose (3.4 kcal/g) from replacement fluids
  • Lactate (3.62 kcal/g) used as buffer 1
• Include these calories in total daily energy provision to avoid overfeeding 1

Route of Administration

• Enteral nutrition is preferred when possible 1
• Parenteral nutrition should be considered when >60% of energy and protein requirements cannot be met via enteral route within 7-10 days 3

Monitoring and Adjustment

• Regular reassessment of nutritional requirements is essential as patient's condition changes 1
• Monitor for metabolic complications:
  • Hyperglycemia
  • Hypertriglyceridemia
  • Fluid retention
  • Electrolyte imbalances 4

Common Pitfalls to Avoid

1. Overfeeding

   • Can lead to increased length of stay, ventilation duration, and infection rates 1
   • A prospective study showed that increasing calorie intake from 30 to 40 kcal/kg/day in critically ill AKI patients resulted in more severe metabolic complications and positive fluid balance without improving nitrogen balance 1

2. Underfeeding

   • Intake below 50% of requirements may lead to severe calorie debt, energy reserves depletion, lean body mass reduction, and increased infectious complications 1

3. Inaccurate Weight Estimation

   • Patients with AKI frequently have fluid overload, making it difficult to determine reference body weight 1
   • Consider using pre-admission or ideal body weight for calculations 2

4. Failure to Account for Metabolic State

   • Studies have shown that 62% of ICU patients with severe AKI are hypermetabolic and 14% are hypometabolic 5
   • Critically ill patients with AKI oxidize fewer carbohydrates and more lipids than expected 1

By following these evidence-based recommendations for caloric requirements in critically ill patients with AKI, clinicians can optimize nutritional support while minimizing complications associated with both under- and overfeeding.