Nutritional support represents one of the most important cornerstones in the management of patients with a moderate to severe burn injury.
Patients suffering burn over 20 percent or more of their body surfaces require special diets during the healing process. Such severe burning significantly boosts the rate at which bodies metabolize nutrients, creating a risk of malnutrition.
Among the key nutritional considerations for severe burn victims are increased protein and high-calorie diets. Burn victims lose protein through their wounds as body systems attempt to regenerate skin and muscle tissues. And extra carbohydrates and fat in burn victims' diets keep energy levels high -- a key ingredient to recovery. Burn Injury Online notes severe burn victims often require up to two extra servings of protein per day through lean meat, fish or dairy. And consuming extra carbohydrates keeps enough body fuel on board, channeling proteins to the process of skin and tissue repair. Fat also provides needed calories for fueling the bodies of burn victims. Doctors often recommend that burn patients receive up to 30 percent of their calories from fat.
The energy expenditure in burns exceeds that of any other injury. Oxygen consumption increases and peaks by day 10 post burn to 2.5 times that of the normal. The caloric needs are estimated roughly on basis of following guidelines –
25 kcals/kg body weight + 40 kcals x % body burns.
Calorie requirements peak between 6th and 10th post burn day and decline to normal levels with complete skin coverage.
Underfeeding has a negative impact on wound healing, immunocompetence and mortality. Over feeding causes hyperglycemia, fatty livers and elevated co2 production.
Patient should be kept warm and pain relief provided.
Protein is the most important nutrient compromised by a burn injury - protein needs can be approximated by using the formula –
1g/kg body wt + 3g x % body burns.
The protein source should be of high biological value. Arginine enriched diet improves cell mediated immunity and healing.
Nitrogen balance is a useful parameter for estimating adequacy of protein intake in burns patient. This can be calculated by the formula –
Nitrogen intake – (24 hour urine urea nitrogen + fecal nitrogen loss g/24 hours + wound nitrogen loss g/24 hours)
Wound nitrogen loss is given as –
<10% open wound=0.02 g nitrogen/kg/day.
11% to 30% open wound=0.05 g nitrogen/kg/day.
>30% open wound=0.12 g nitrogen/kg/day.
Nitrogen excretion should be decreased as the wounds heals or are grafted.
Efficient use of nitrogen requires simultaneous administration of potassium which is excreted heavily after a burn. The potassium-to-nitrogen ratio should be 6:1 until the late convalescent phase.
The burn wound metabolizes large quantities of glucose to lactic acid; this pathway is favoured by healing wounds. Hyperglycemia is common during the acute phase following thermal injury and this should be monitored and controlled using exogenous insulin carbohydrates are beneficial as nutritional substrates and help in utilization of protein. However excessive carbohydrate intake causes side effects.
Conservative ingestion of fats is beneficial. Giving 15-20% of non protein calories as fats is optimal supplementation with omega – 3 fatty acids improve immuno competence.
The administration both enterally & parenterally, of low fat formula results in less pneumonia, improved respiratory function, faster recovery of nutrition status and a shorter length of care.
Daily multivitamin supplementation is important. Enrichment with vitamins A and C and zinc is also necessary.
- 5000 IU of vitamin A per 1000 kcalories helps in epithelialization and maintenance of immunologic response.
- Vitamin C is important in collagen synthesis and immune function and required in increased amount of wound healing, its usual doses 500 mg twice daily . Ingestion of 1gram of vitamin C is also necessary.
- Supplementation with 220 mg of zinc sulphate daily is recommended.
- Administration of calcium to treat hypocalcemia, and supplemental magnesium & phosphorus are given to prevent gastrointestinal irritation.