Burns (1)

NUTRITION OF THE BURNED PATIENT

Prepared by

Rania Hassan Abdel Hafiez

Effects of Burn on the Body

Extensive inflammatory response Rapid fluid shifts and accumulation. Hypermetabolic state Muscle protein catabolism Decrease cardiac output because of increased

capillary permeability and vasodilation. Heat loss Increased blood glucose levels Burn Shock

Nutrition Therapy Goals

Promote wound healingMaintain lean body massRestore fluid levels

Hypermetabolism

Catecholamines, cortisol, and other glucocorticoids are increased in burn victims due to the stress state of the body causing a hypermetabolic response.

Epinephrine and norepinephrine increase 10-fold in people with burns greater that 30-40%.

Hypermetabolic state lasts 9-12 months after a burn.

Glucose Metabolism

Accelerated gluconeogenesis, glucose oxidation and plasma clearance of glucose

Blood glucose levels increase due to insulin resistance and breakdown of glycogen stores

Glucagon excretion by the liver increases initially after the burn and slows down as wound heals

Muscle Protein Catabolism

Protein catabolism increases in burn patients leading to protein losses of 260 mg protein/kg/hr.

Catabolic hormones counteract the effect of insulin; as a result, blood sugar levels rise, and protein synthesis and lipogenesis are inhibited. Growth hormone is similarly antagonized and less effective.

In this environment, skeletal muscle is the major obligatory fuel. (compare to starvation)

Role of Specific Nutrients:

Kilocalories Supplied by carbohydrate, protein, fat Needed for optimal tissue repair Required for synthesis of new cells Sufficient calories is a priority so that

protein will be spared

Determining Kcal Needs

Calculation of energy needs for the burn patient remains challenging % TBSA Degree of burn Other trauma involved

Determining Kcal Needs

Predictive formulas At least 30 formulas have been proposed

Harris-Benedict Equation: adds activity factor and stress factor

Ireton-Jones Equation: accounts for age, weight, gender, presence of trauma or burn, and ventilatory status

Kcalories/kg Used for less severe burns (<20% TBSA)

Determining Kcal Needs

Indirect Calorimetry (Metabolic Cart) Considered to be the “gold standard” An indirect method of calculating energy

expenditure and respiratory quotient using measurements of inspired and expired gas

Most closely related to actual energy expenditure

Accounts for variability in energy expenditure from changes in metabolic state

Determining Kcal Needs

Indirect Calorimetry, continuedRequirements for a valid measurement:

Hemodynamically stable patientA cooperative or sedated patientPeriod of rest before measurementFiO2 < 60%Absence of chest tubes or other sources of air leak

Table 1: Nutrition Support for Burn Injuries

Stressors Stress Factors

Activity factor

Confined to bed 1.2

Out of bed 1.3

Injury factor

Minor operation 1.2

Skeletal trauma 1.3

Major surgery 1.4

Sepsis 1.6

Burn factor Stress Factors

20% TBSA 1.2

20–25% TBSA 1.6

25–30%TBSA 1.7

30–35% TBSA 1.8

35–40% TBSA 1.9

40% TBSA 2.0

Table 1 Use of the modified Harris-Benedict equations to estimateresting energy expenditureMen: BEE=(66.47+13.75W+5.0H-6.76A)x(Activity Factor)x(Injury and/or Burn Factor)Women: BEE=(655.1+19.56W+1.85H-4.68A)x(Activity Factor)x(Injury and/or Burn Factor)

W=weight in kg; H=height in cm; A=age in years.

Monitoring Nutritional Status

Body Weight Weight should be measured regularly Goal of weight maintenance is within 90%-

110% of pre-burn weight

Prealbumin Short half-life of 2-3 days Reflects recent nutrition intake Depressed during acute phase response to burn

Monitoring Nutritional Status

Nitrogen Balance Evaluates the adequacy of protein intake

Needs a 24 hour urine collection and a 24 hr UUN lab test

Nitrogen balance = nitrogen intake - nitrogen losses

Monitoring Nutritional Status

Nitrogen Balance, continued Nitrogen intake = protein intake/6.25

Nitrogen losses = Urinary nitrogen losses (24 hr UUN) Other losses from non-urea urinary nitrogen, fecal,

sweat, etc. (3-5 g) Burn wound nitrogen losses

<10% open wound = 0.02 g/kg 11% to 30% open wound = 0.05 g/kg >30% open wound = 0.12 g/kg

Monitoring Nutritional Status

Indirect Calorimetry (Metabolic Cart) Periodic measurements aid in evaluating

adequacy of caloric intake

Measures resting energy expenditure (REE) A factor of 10% to 30% added for calorie needs

during PT and wound care

Protein Requirements

Amino acids are important for collagen synthesis for wound healing

Maintaining visceral protein is important for organ function especially for immune systems Maintaining intercostal muscles and the

diaphragm is imperative for respiratory efficiency

1.4-2.2 g/kg protein requirement for burns Urinary nitrogen losses increase with severity of

the burn injury Trauma patient may lose 20-25 g of lean body

nitrogen daily

Protein Requirement cont…

Protein requirement estimate: Combine 24-hour urinary nitrogen loss, 2 to 4 g

of nitrogen for fecal loss and 4 to 5 g/d for anabolism.

Convert each gram of nitrogen to 6.25 g of protein.

Patients are likely to miss feedings if in surgery frequently so should be given high protein formulas between surgeries Be aware of uremia- increase free water

Generally 20-25% of calories from protein

Lipid requirements

Lipid stores are critical for long-term fuel after major thermal burns

Fat oxidation is higher in hypermetabolic patients than in normal patients

Fat consumption should not exceed 30% of the diet to avoid diarrhea

Beneficial because Fat is a more concentrated form of energy Vegetable oils contain essential fatty acids and

fat soluble vitamins Help with infection

Carbohydrate Requirements

Carbohydrate metabolism is significantly affected in burn patients Gluconeogenesis from Alanine and other AAs are

elevated Carbohydrates are good sources for protein

sparing especially for nitrogen retention High carbohydrates can contribute to

hyperglycemia in which case a diet can be altered to increase fat in the diet

Recommended 60% of the calories from CHO, not surpassing 400g/d or1600 kcal/d

Vitamin C

Needed for edema prevention Involved in collagen synthesis for wound

healing Aid in immune functioning

Vitamin A

Needed for immune function Epithelialization 5000 IU of Vitamin A per 1000

cal of enteral feeding is recommended

Vitamin D and Calcium

Burns cause an impairment in the metabolism of Vitamin D

Burn patients are more susceptible to fractures so calcium and vitamin D should be administered

Calcium- 1000 mg daily Vitamin D- 200-400 IU daily

Maintain serum 25-hydroxy vitamin D level of 30-60 ng/Ml

Zinc and Copper

Zinc and copper deficiencies have been seen in burn patients most likely from tissue breakdown and urinary excretion.

Supplementation is recommended for patients

Conditionally essential amino acids

Glutamine

Methods of Nutrient Delivery

Oral Intake Burns <25% TBSA in older children and adults and <15% TBSA in young children and infants

High-calorie, high-protein supplements

Modular calorie and protein enhancement of oral foodstuffs

Methods of Nutrient Delivery

Enteral Nutrition (EN) Most burn patients can tolerate a

standard formula Formula with high nitrogen content Transpyloric feedings are better tolerated

EN is preferred to parenteral nutrition

(PN)

Methods of Nutrient Delivery

Parenteral Nutrition (PN, TPN, PPN) Associated with complications

Intestinal dysmotility Hepatic steatosis Septic morbidity Catheter-related infection

ASPEN guidelines: limit use of PN to patients in whom EN is contraindicated or unlikely to meet nutritional needs in 4-5 days

Conclusions

An aggressive nutrition approach for the burn patient is indicated to: address hypermetabolism enhance nitrogen retention support wound healing improve survival

Adequate nutrition

Successful wound healing

He has too much food to eat

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