Is Peptamen (peptide-based formula) a suitable option for nutritional support in a patient with Acute Kidney Injury (AKI)?

Peptamen for Acute Kidney Injury

Peptamen (a peptide-based enteral formula) is an appropriate nutritional option for patients with AKI who require enteral nutrition support, as there is no evidence that reduced renal function increases complications during enteral feeding, and the enteral route should be the preferred method of nutritional delivery in these patients. 1

Route of Nutrition: Enteral First

• Enteral nutrition (EN) should be the first-line approach for nutritional support in AKI patients when the gastrointestinal tract is functional. 1, 2
• EN is safe and effective in AKI without increased gastrointestinal, mechanical, or metabolic complications compared to patients with normal renal function. 1, 2
• The enteral route reduces ICU-acquired infections and shortens ICU/hospital stays compared to parenteral nutrition. 3
• Parenteral nutrition should only be considered when the gastrointestinal tract is non-functional, inaccessible, or when EN fails to meet at least 70% of nutritional requirements. 1, 3

Peptide-Based Formulas in AKI

• There is no specific contraindication to using peptide-based formulas like Peptamen in AKI. The choice between standard polymeric formulas and peptide-based formulas should be based on gastrointestinal tolerance rather than kidney function. 1
• Standard enteral formulas have been shown to be safe and effective in AKI patients, with one large observational study of 182 AKI patients demonstrating that both standard and disease-specific formulas for kidney failure were well-tolerated. 1
• High gastric residuals may be more frequent in AKI patients, but this does not preclude the use of enteral feeding—it simply requires monitoring and slow advancement. 1

Nutritional Targets in AKI

Energy Requirements

• Target 20-30 kcal/kg/day for total energy intake in AKI patients. 1
• For non-critically ill patients ≥60 years old with AKI, target 30-35 kcal/kg/day. 1, 4
• Indirect calorimetry should be used when available to assess energy expenditure and avoid under- or overfeeding, as predictive equations are subject to significant bias in kidney patients. 1

Protein Requirements

• Non-catabolic AKI patients not on dialysis: 0.8-1.0 g/kg/day of protein. 1
• AKI patients on renal replacement therapy (RRT): 1.0-1.5 g/kg/day. 1
• Hypercatabolic AKI patients or those on continuous RRT: up to 1.7 g/kg/day. 1
• Do not restrict protein intake with the aim of preventing or delaying initiation of RRT—this practice is not supported by evidence. 1

Initiation and Advancement Strategy

• Start EN at low rates and increase slowly over days to meet requirements and minimize risk of refeeding syndrome. 1, 3
• For critically ill AKI patients staying in the ICU for more than 48 hours, medical nutrition therapy should be provided. 1
• For non-critically ill hospitalized AKI patients who are malnourished or at risk of malnutrition and cannot meet nutritional requirements with regular diet alone, oral nutritional supplements (ONS) should be offered. 1

Critical Monitoring Parameters

• Plasma electrolytes and phosphorus must be strictly monitored during nutritional support to prevent refeeding syndrome, especially in severely malnourished patients or those with reduced food intake before admission. 1, 2, 4
• Monitor for hyperglycemia, hypertriglyceridemia, fluid retention, and acid-base derangements, as AKI patients are especially prone to these complications during nutritional support. 5, 6
• Serial creatinine measurements every 24-48 hours should be obtained to assess response to treatment. 2
• Target urine output >0.5 mL/kg/h to assess response and avoid oliguria. 2

Common Pitfalls to Avoid

• Do not unnecessarily restrict protein in AKI patients out of fear of worsening azotemia—inadequate protein intake may harm nutritional status and result in poorer clinical outcomes. 7
• Do not delay enteral nutrition in favor of parenteral nutrition when the gut is functional—EN has superior outcomes. 1
• Do not use disease-specific "renal formulas" routinely unless there are specific electrolyte concerns or the patient is on chronic dialysis—standard formulas are generally appropriate and safe. 1
• Ensure adequate fluid intake (at least 1.6 L/day for older women, 2.0 L/day for men from all sources) while monitoring for fluid overload. 2