What are the nutritional requirements for critical burn patients?

Nutritional Requirements for Critical Burn Patients

Critical burn patients require early enteral nutrition within 24 hours, providing 1.5–2 g/kg/day of protein, with energy targets of 20–25 kcal/kg/day during the acute phase, advancing to 25–30 kcal/kg/day during recovery, using high-carbohydrate (≥60%) and low-fat (≤15%) formulas, supplemented with glutamine and higher-than-standard doses of trace elements (copper, selenium, and zinc). 1

Timing and Route of Nutrition

• Initiate enteral nutrition within 24 hours of burn injury to decrease muscle protein catabolism, improve wound healing, reduce ICU and hospital length of stay, diminish sepsis rates, and decrease risk of Curling ulcer formation 1
• Enteral nutrition is the preferred route over parenteral nutrition in burn patients who can tolerate it 1
• Use supplemental parenteral nutrition only if enteral targets cannot be met 1

Energy Requirements

Acute Phase (First Days to Week)

• Limit energy provision to 20–25 kcal/kg/day during the acute and initial phase of critical illness, as excess may be associated with less favorable outcomes 1
• Resting metabolic rate can reach up to 180% of basal rate in the first week following thermal injury 1

Recovery Phase

• Target 25–30 kcal/kg/day during the anabolic recovery phase 1
• Metabolic rate remains elevated to 130%–150% at time of full healing, 120%–140% at 6 months, and 110%–120% at 12 months 1

Monitoring

• Serial indirect calorimetry is the best option to fully meet energy targets in burn patients 1
• When indirect calorimetry is unavailable, the Toronto formula is the most accurate proxy for energy expenditure 1

Macronutrient Composition

Protein

• Provide 1.5–2 g/kg/day of protein to increase protein synthesis and reduce negative nitrogen balance 1
• Burn patients oxidize amino acids at a rate 50% higher than baseline due to profound protein catabolism 1
• Protein rates exceeding 2 g/kg/day have not demonstrated additional benefits 1

Carbohydrates

• Use high-carbohydrate formulas providing ≥60% of total calories 2
• Glucose oxidation increases from 4–5 to 7 g/kg/day after thermal injury 1
• Avoid excess carbohydrate provision as it can propagate hyperglycemia with subsequent exacerbation of inflammation, muscle breakdown, and excess fat production 1
• Nearly all burn patients exhibit some degree of insulin resistance 1
• Administer insulin to improve lean body mass, bone mineral density, donor site healing, and decrease length of stay, though careful monitoring is required to avoid hypoglycemia 1

Fat

• Limit fat to ≤15% of total calories 2
• Low-fat diets help avoid exaggerated immunosuppression 1
• Evidence for omega-3 fatty acid supplementation is mixed; a recent systematic review and meta-analysis was unable to appreciate benefit of ω-3 support in burn patients 1
• High-carbohydrate, low-fat nutrition has been shown to decrease pneumonia rates, wound infections, acute respiratory distress syndrome, fatty liver, and sepsis, while improving nitrogen balance and shortening hospital length of stay 2

Micronutrient Supplementation

Trace Elements

• Supplement copper, selenium, and zinc in higher-than-standard doses in burn patients 1
• These trace elements are critical given the oxidative stress and wound healing demands 1

Glutamine

• Add glutamine to standard enteral formula in burn patients 1
• The 2018 ESPEN guidelines recommend additional enteral glutamine in patients with burns involving >20% body surface area 1
• However, recent high-quality evidence from an international multicenter RCT found no reduction in time to discharge, 6-month mortality, hospital length of stay, or incidence of bacteremia compared with placebo 1
• Despite equivocal evidence, glutamine administration is unlikely to cause harm and may be considered given the guideline recommendations 1

Vitamins and Minerals

• Consider supplementation with vitamins A, B-1, B-6, B-12, C, D, and E, as well as iron, copper, selenium, zinc, and magnesium to improve wound healing and immune function 1
• Supplementation has been shown to lower risk of wound infection (30% vs 77.4%), sepsis (13.3% vs 41.9%), and prolonged hospitalization 1
• Monitor key micronutrients in major burn patients, particularly those on continuous renal replacement therapy for >5 days 1
• Given limited risk of low-dose mineral supplementation, they may be considered in patients with severe burns 1

Formula Selection

• Use whole protein formulas as no clinical advantage of peptide-based formulas has been shown 1
• No recommendation for immune-modulating formulas (enriched with arginine, nucleotides, and omega-3 fatty acids) can be given for burn patients due to insufficient data 1

Common Pitfalls

• Avoid overfeeding during the acute phase, as energy provision exceeding 20–25 kcal/kg/day may worsen outcomes 1
• Do not delay enteral nutrition; the 24-hour window is critical for optimal outcomes 1
• Monitor for hyperglycemia closely given the profound insulin resistance and increased glucose oxidation in burn patients 1
• Adjust nutrition therapy continuously based on disease progression and gut tolerance, as no single fixed amount applies throughout recovery 1