Burns

BURNS

Discussion
Thermal trauma results in marked hypermetabolism and hypercatabolism. Aggressive nutritional support is required to meet metabolic demands, prevent the depletion of body energy and nitrogen stores, support wound healing, enhance immunity, and improve survival (1-3). Energy requirements increase linearly in proportion to burn size to a maximum of approximately twice the normal levels (1). Factors such as agitation, pain, and heat loss during dressing changes are associated with a large increase in energy expenditure (1).

Approaches
Energy requirements in adults: Many formulas are available to determine energy requirements. Unfortunately, many of these formulas have not been validated for the burn population (1,-3). The expert consensus is that indirect calorimetry should be used to evaluate resting energy expenditure (REE) on admission to the hospital and at least once weekly until the patient is stabilized (1,3). Indirect calorimetry should be performed late at night or early in the morning (before daily activities) to obtain a more accurate assessment of REE (1). In addition, indirect calorimetry is recommended when the patient’s condition is complicated by infection, sepsis, poor wound healing, obesity, or ventilator dependency (1). The REE obtained from indirect calorimetry should be multiplied by a factor of 1.3 (or 20% to 30%) to account for activity and stress of treatments (1,4,5). This figure provides the total energy expenditure for which the clinician would base the nutrition prescription.

If indirect calorimetry is not available, evidence based guidelines recommend using the following predictive equations (listed in order of accuracy) Penn State, Swinamer, and Ireton-Jones equations for use in calculating the REE in non-obese critical care patients (6). (See Estimation of Energy Requirements.) The Curreri formula has also been suggested for burn patients (3). The values obtained from these equations are approximate and should be used only as guidelines in predicting energy requirements in burn patients (1-3) .

Based on the REE equation and the parameters accounted for in the equation (eg, burn, non-burn, ventilator-dependent, or spontaneous breather), an injury factor, which is based on the percent of total body surface area burned (TBSAB), and an activity factor may need to be multiplied with the baseline REE to obtain total energy expenditure (1-4).The clinician should be aware that the practice of adding injury and stress factors has not been validated and may lead to the over estimation of the patient’s needs (6). Patient’s who are mechanically ventilated, sedated or paralyzed due to severity of injury often have reduced energy needs (3). Chemical neuromuscular paralysis decreases energy requirements of critically ill patients by as much as 30% (3).

Physical Activity Level	Activity Factor	Percent TBSAB	Injury Factor (1,5)
Bed rest	1.2	<20%	1.2-1.4
Ambulatory	1.3	20%-25%	1.6
		26%-30%	1.7
		31%-35%	1.8
		36%-40%	1.9
		41%-50%	2.0

As previously mentioned, The Curreri formula is a tool for specifically deriving the energy needs of burn patients (7,8). However, it may overestimate the patient’s nutrition needs, particularly during convalescence (1,-3). The Curreri formula appears to be most useful during the early postburn phase (7-to-10 days postburn), when energy expenditure is at its maximum. This formula also provides guidelines for use in the overweight and obese populations (8).

Curreri formula for patients aged 16 to 59 years:
25 kcala x kg actual body weight + (40 kcal x % TBSABb based on actual weight in kg)

For example, a 190-lb man with 35% TBSAB:
25 kcal x 86 kg + [40 kcal x 30 kg (35% of 86 kg is 30 kg)] = 3,350 kcal/day

Curreri formula for patients aged 60 years and older:
20 kcal a x kg actual body weight + (65 kcal x % TBSABb based on actual weight in kg)

aIf BMI >27, use 15 to 18 kcal
bIf the percent TBSAB >50%, use a maximum value of 50%

Energy requirements in children: Indirect calorimetry, if available, should be used on admission to the hospital and twice weekly thereafter until the patient is healed. The REE should be multiplied by a factor of 1.3 (or 20% to 30%) to provide total energy needs (1,9).

For less than 30% TBSAB, use the Dietary Reference Intakes (DRI) for energy, per age group, as a starting point to provide adequate energy intake (5). (See Dietary Reference Intakes).   For greater than 30% TBSAB, use the following formulas, where BSA = Body Surface Area and BSAB = Body Surface Area Burned (10):

Galveston infant                0 to 12 months       2,100 kcal/m2 BSA + 1,000 kcal/m2 BSAB
Revised Galveston            1 to 11 years          1,800 kcal/m2 BSA + 1,300 kcal/m2 BSAB
Galveston adolescent 12 to 18 years         1,500 kcal/m2 BSA + 1,500 kcal/m2 BSAB

The Curreri formula, which was proposed to calculate the energy needs of the burned adult, has been modified for pediatric patients by using balance studies of weight in burned children (11). The Curreri junior formula is designed for burns of less than 50% total body surface area. It typically overestimates energy requirements in burns exceeding 50%.

Age 0 to 1 year: Basal kcal + 15 kcal x % Burn
Age 1 to 3 years: Basal kcal + 25 kcal x % Burn
Age 3 to 15 years: Basal kcal + 40 kcal x % Burn

Protein requirements: Protein needs of burn patients are directly related to the size and severity of the burn. The increased protein demand is necessary to promote adequate wound healing and to replace nitrogen losses through wound exudate and urine. Failure to meet heightened protein needs can yield suboptimal clinical results in terms of wound healing and resistance to infection. Infants and children further adapt to inadequate protein intake by curtailing growth of cells, conceivably sacrificing genetic growth potential.

Adults (1,12,13)
<10% TBSAB                        1.2 to 1.5 g/kg of actual or ideal body weighta
10% to 15% TBSAB              1.5 to 2.0 g/kg of actual or ideal body weighta
15% to 35% TBSAB              2.0 to 2.5 g/kg of actual or ideal body weighta
>35% TBSAB                        23% to 25% of total energy
aConsider using ideal body weight when an actual weight cannot be evaluated or measured, or in cases of severe obesity in which protein requirements may be overestimated if the actual body weight is used.

Children (9,14,15)
<1% TBSAB                          3 to 4 g/kg
1% to 10% TBSAB                15% of total energy or non-protein calories to nitrogen ratio (NPC:N) of 150:1
>10% TBSAB                        20% of total energy or NPC:N of 100:1

Other estimates of protein needs of the burn patient include (12):

For patients 1 year of age to adults, use a total calorie to nitrogen ratio of 120:1.
Calculate nitrogen balance from a 24-hour urine collection analyzed for urea urinary nitrogen (UUN):

Nitrogen balance = [(24-hour UUN ´ 1.1) + (1 g for stool losses) + (estimated wound nitrogen lossa)] x 6.25 g of protein per gram of nitrogen (9)

awound nitrogen (N) loss:        ≤10% open wound = 0.02 g N/kg per day
                   11% to 30% open wound = 0.05 g N/kg per day
awound nitrogen (N) loss:        ≥31% open wound = 0.12 g N/kg per day

Parenteral Nutrition
Carbohydrate (3,4,13,16)

Adults	3 to 4 mg/kg per minute parenteral glucose infusion or approximately 50 to 60% of total energy requirements in critically ill burn patients (3,17). Insulin should be used to maintain normoglycemia (3,18-19).
Children	Initiate dextrose at 7 to 8 mg/kg per minute and advance as needed to maximum of 20% dextrose solution.
Infants	Initiate dextrose infusion at 5 mg/kg per minute and advance to 15 mg/kg per minute over a 2-day period.

For all burn patients, carbohydrates should account for approximately 50% of total energy.

Fat (3,15,16)
Adults 10% to 30% of total energy in critical care with 2 % to 4% as essential fatty acids to prevent deficiency (3).
Children >1 year 30% to 40% of total energy
Children <1 year Up to 50% of total energy

Replacing omega-6 fatty acid with omega-3 fatty acid may help avoid or reverse postburn immunosuppression (3,4).

Percent TBSAB	Feeding Approach
<20% (if not complicated by facial injury, inhalation injury, or preburn malnutrition)	High-energy, high-protein oral diet is generally sufficient.
>20%	Nocturnal tube feeding to supplement dietary intake during the day may be adequate to meet needs; use nutrient intake analysis to ensure adequate intake.

If feeding is to be given totally by nutrition support, the enteral route is preferred over total parenteral nutrition (3). Starting an intragastric feeding immediately after the burn injury (6 to 24 hours) has been shown to be safe and effective. Total parenteral nutrition should be reserved for only those patients with prolonged alimentary tract dysfunction. Gastric ileus is common in centrally injured burn patients. For these patients, a transpyloric feeding may be indicated.

Micronutrient Requirements (16)
Electrolytes	Provide based on serum and urine data and fluid needs.
Minerals	DRI
Trace elements	DRI
Minor burns (<10% TBSAB) in all children and adults	One multivitamin daily
Major burns (>0% to 20% TBSAB) in children younger than 3 years	One multivitamin daily Vitamin C 250 mg twice daily Vitamin A 5,000 IU daily Zinc sulfate 110 mg daily
Major burns (>20% TBSAB) in adults and children at least 3 years old	One multivitamin daily Vitamin C 500 mg twice dailya Vitamin A 10,000 IU daily Zinc 45-50 mg dailya

aRecommended delivery in suspension for tube feeding because oral vitamin C and zinc in large doses may precipitate nausea or vomiting (3).

References

Burns. In: Nutrition Care Manual. American Dietetic Association; 2007. vailable at: nutritioncaremanual.org. Accessed October 15, 2007.
Mayes T, Gottschlich MM. Burns and wound healing. In: Gottschlich MM, ed. The Science and Practice of Nutrition Support: A Case-Based Core Curriculum. Dubuque, Iowa: American Society of Enteral and Parenteral Nutrition; 2001:338-341.
Cresci GA, Gottschlich MM, Mayes T, Mueller C. Trauma, Surgery, and Burns. In: Gottschlich MM ed. The A. S. P. E. N. Nutrition Support Core Curriculum: A Cased-Based Approach- The Adult Patient. Silver Spring, MD: American Society of Enteral and Parenteral Nutrition; 2007:455-476.
Waymack JP, Herndon DN. Nutritional support of the burned patient. World J Surg. 1992;16:80-86.
Rodriguez DJ. Nutrition in major burn patients: state of the art. Support Line: A Publication of Dietitians in Nutrition Support. 1995;7:1-8.
Critical Illness Evidence-Based Nutrition Practice Guideline. American Dietetic Association Evidence Analysis Library. American Dietetic Association; 2006. Available at: http://www.adaevidencelibrary.com. Accessed October 10, 2007..
Curreri PW, Richmond D, Marvin J, Baxter CR. Dietary requirements of patients with major burns. J Am Diet Assoc. 1974; 65:415-417.
Gottschlich MM, Ireton-Jones CS. The Curreri formula: a landmark process for estimating the caloric needs of burn patients. Nutr Clin Pract. 2001;16:172-173.
Mayes T, Gottschlich M, Khoury J, Warden GD. Evaluation of predicted and measured energy requirements in burned children. J Am Diet Assoc. 1996;96:24-29.
Hildreth M, Herndon DN, Desai MH, Broemeling LD. Caloric requirements of patients with burns under one year of age. J Burn Care Rehabil. 1993;14:108-112.
Curreri PW, Richmond D, Marvin J, Baxter CR. Dietary requirements of patients with major burns. J Am Diet Assoc. 1974;65:415-417.
Hildreth M, Gottschlich M. Nutritional support of the burned patient. In: DN Herndon, ed. Total Burn Care. Philadelphia, Pa: WB Saunders; 1996.
Deitch EA. Nutritional support of the burn patient. Crit Care Clin. 1995;11:735-750.
O'Neil CE, Hutsler D, Hildreth MA. Basic nutritional guidelines for pediatric burn patients. J Burn Care Rehabil. 1989;10:278-284.
Farrell K, Bradley S. Estimation of nitrogen requirement in patients with burns. J Burn Care Rehabil. 1994;15:174.
Gottschlich MM, Warden GD. Vitamin supplementation in the patient with burns. J Burn Care Rehabil. 1990;11:257-279.
A.S.P.E.N. Board of Directors. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. J Parenter Enteral Nutr. 2002;26(suppl): 88SA-93SA.
Hansen T, Thiel S, Wouters P, Christiansen JS, Van de Berghe G. Intensive insulin therapy exerts anti-inflammatory effects in critically ill patients, as indicated by circulating mannose-binding lectin and C-reactive protein levels. J Clin Endocrinol Metab. 2003;88:1082-1088.
Van den Berghe G, Wouters PJ, Weekers F, Verwaest C, Bruyninckx F, Schetz M, Vlasselaers D, Ferninande P, Lauwers P, Bouillon R. Intensive insulin therapy in critically ill patients. N Engl J Med. 2001;345:1359-1367.