66.5 + 13.8 (weight in kg) + 5 (height in cm) − 6.76 (age in years)
655 + 9.6 (weight in kg) + 1.85 (height in cm) − 4.68 (age in years)
Estimates basal energy expenditure; can be adjusted by both activity and stress factor, multiply by 1.5 for common burn stress adjustment
−4343 + 10.5 (TBSA) + 0.23 (calorie intake in last 24 h) + 0.84 (Harris Benedict estimation without adjustment) + 114 (temperature) − 4.5 (number of postburn days)
Useful in acute stage of burn care; must be adjusted daily
Davies and Lilijedahl
20 (weight in kg) + 70 (TBSA)
Often overestimates caloric needs for large injuries
1784 − 11 (age in years) + 5 (weight in kg) + (244 if male) + (239 if trauma) + (804 if burn)
629 − 11 (age in years) + 25 (weight in kg) − (609 if obese)
Complex formula that integrates variables for ventilation and injury status
Age 16–59: 25 (weight in kg) + 40 (TBSA)
Age >60: 20 (weight in kg) + 65 (TBSA)
Commonly overestimates caloric needs
2100 (body surface area) + 1000 (body surface area × TBSA)
1800 (body surface area) + 1300 (body surface area × TBSA)
1500 (body surface area) + 1500 (body surface area × TBSA)
Goal focuses on maintaining body weight
<1 year: recommended dietary allowance + 15 (TBSA)
1–3 years: recommended dietary allowance + 25 (TBSA)
4–15 years: recommended dietary allowance + 40 (TBSA)
Commonly overestimates caloric needs
Indirect calorimetry is currently the gold standard for energy expenditure measurement, but it is difficult to perform and as such is not practical on a routine basis. Indirect calorimetry measurement calculates oxygen consumption and carbon dioxide production and therefore metabolic rate by measuring the volume of expired gas and the oxygen and carbon dioxide concentration of the inhaled and exhaled gas via a face mask or ventilator. Under or overfeeding can be detected by calculating the ratio of carbon dioxide produced to oxygen consumed, known as the respiratory quotient (RQ) . RQ is dependent on metabolism of specific substrates. Fat is the major energy source during unstressed starvation which gives an RQ of approximately 0.7. Normal metabolism of mixed substrates gives an RQ between 0.75 and 0.90. Overfeeding is characterized by the creation of fat from carbohydrate and leads to an RQ greater than 1.0, which explains why overfeeding can cause difficultly in weaning a patient from the ventilator . It is important to note that despite this concern, one study found that in a group of pediatric burn patients, a high-carbohydrate diet did not result in an RQ over 1.05 or any other respiratory complications but did have the positive effect of decreased muscle wasting .
21.6 Nutrient Metabolism
Carbohydrates, lipids, and proteins are the three macronutrients that provide energy and biological building blocks to fuel complex metabolic processes. They provide energy via different pathways, and the ratios of these nutrients must be considered for the burn patient after a caloric goal has been determined.
Carbohydrates are the preferred source of energy for burn patients, and high carbohydrate diets improve wound healing and have a protein sparing effect. In a randomized study of severely burned children, those who were fed a high carbohydrate diet had significantly less muscle protein degradation than those on a high-fat diet . These positive effects are, however, limited by the ability to oxidize and utilize glucose. Glucose administration more than 9 mg/kg/min cannot be oxidized at the upper limit, and therefore, this strategy cannot be used above this range. Unfortunately, this maximum rate can be less than the estimated caloric expenditure, inferring some burned patients may have greater glucose needs than can be given safely. If glucose is given at a higher rate than this, it leads to hyperglycemia, glycosuria, dehydration, conversion of glucose to fat, and respiratory problems [35, 36].
Protein is also an important macronutrient after burn and must be carefully considered in the development of a nutritional support plan. Protein needs are greatly increased in these patients because of the catabolic response to burn, and protein supplementation is vital to meet the ongoing demands and supply substrate for wound healing and immune function and to mitigate the loss of leady body mass . Giving supra-normal protein doses does not decrease catabolism of endogenous protein stores, but it does promote protein synthesis and improved nitrogen balance . Predicted protein requirements are 1.5–2.0 g/kg/day for burned adults and 2.5–4.0 g/kg/day for burned children. Protein should always be provided in addition to considerable calories from carbohydrates and fat; otherwise, the protein will be used only as an energy source instead of as a specific nutrient to provide substrate for wound healing and maintenance of muscle mass. Optimal non-protein to nitrogen ratio is a function of burn size and should be around 150:1 for smaller burn up to 100:1 for larger burns . Despite high rates of protein supplementation, burn patients will experience some loss of muscle protein because of the hormonal and proinflammatory reaction to severe burn.
Two specific amino acids have been studied and found to play unique roles after burn. Glutamine provides direct energy for lymphocytes and enterocytes and is crucial for preserving small bowel integrity and sustaining gut-associated immune function [40, 41]. It also portends some degree of cellular protection after stress via increased production of heat shock proteins, and it is a precursor of an important antioxidant, glutathione [42, 43]. Supplementation of 25 g/kg/day of glutamine has shown to reduce mortality and length of stay in burn patients [44, 45]. Arginine is another important amino acid with significant effects on the immune system. Arginine supplementation in burn patients led to improvement in wound healing and immune responsiveness; however, data from critically ill nonburn patients suggest that it is potentially harmful [46–49]. For this reason, arginine supplementation is not currently recommended in burn patients, but further investigations are underway.
Lipids are necessary to prevent essential fatty acid deficiency, but fat supplementation is only recommended in limited doses . Lipolysis and lipid mobilization are increased after burn, while at the same time, utilization of lipids as an energy source is decreased [51, 52]; most free fatty acids are not used and lead to lipid accumulation in the liver. Increased fat intake has also been shown to worsen immune function, and because of these effects, burn patients should have no more than 15% of their calories from lipids. Many forego lipid emulsions completely for patients receiving parenteral nutrition for less than 10 days. The composition of administered fat must also be considered. Many of the commonly used enteral formulas contain omega-6 fatty acids which create proinflammatory cytokines during metabolism. Lipids with a high proportion of omega-3 fatty acids do not promote proinflammatory mediators and have been associated with improved immune response, less hyperglycemia, and improved outcomes [53, 54]. Omega-3 fatty acids are a component of “immune-enhancing diets” because of these effects. Most formulas have an omega 6:3 ratio ranging from 2.5:1 to 6:1, but the “immune-enhancing diets” have a ratio closer to 1:1. The optimal composition and volume of fat in the diet of burn patients is still controversial and deserves further investigation.
Recommended micronutrient supplementation
Vit A, IU
Vit D, IU
Vit E, IU
Vit C, IU
Vit K, μg
21.8 Enteral and Parenteral Formulas
Selected adult enteral nutrition formulas 
Carbohydrate, g/L (% calories)
Protein, g/L (% calories)
Fat, g/L (% calories)
IED with arginine, glutamine fiber
IED with arginine, hypertonic
Low carbohydrate, for diabetic patients
Concentrated, for patients with renal failure