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THE
BURN NUTRITION MODULE
Section VI
How
to provide optimal nutrition? (Role of Nutritional Supplements)
FOOD
-
Providing
optimum nutrition early including:
-
Use
of anabolic agents if needed to increase the rate of
anabolic activity
-
Providing
excercise stimulus to muscles
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NUTRITION:
Basic Principles
Optimum
nutrition is essential to keep up with the increase calorie demands and
to decrease the rate of catabolism or use of body protein for
fuel. The objective is first provide the calorie and
protein demands, The second objective is to provide the
appropriate nutrient mix.
Nutrient
Mix: Carbohydrate (CHO) calories are provided at about 60% of
total calories. Excess CHO however is deleterious leading to
hyperglycemia and fat formation. Fat calories (20-25% of
total), are provided to reach the energy demands. Endogenous fat
stores are also used. Fat will not spare protein loss. Excess fat,
is also deleterious, being a substrate for immunosuppressive mediators.
Protein:
Protein requirements are 2-3 times the recommended daily allowance (RDA
= 0.8g/kg/day), being 1.5-2 grams/kg body weight per day. THe
increased protein intake will decrease the net N losses by increasing
the amino acid flow into the protein synthesis channel. Glutamine
is the most prominent amino acid lost in muscle and should be provided
in increased amounts preferably orally (10-30 grams/day).
Micronutrients
must be given in increased quantities (5-10 times the RDA) to keep up
with the increase metabolism and quickly restore deficiencies.
Timing:
It is essential to initiate nutrient support as soon as possible after
the catabolic insult. Nutrition should begin within 48 hours of
the catabolic insult, especially in the presence of mild to moderate
malnutrition.
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Choices
for Route of Nutrient Delivery |
| Route:
Enteral
(First Choice) |
Parenteral
(Second Choice) |
Advantage:
- Improves
nutrient utilization, especially protein
- Protects
gut mucosa
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Advantage
- Can
initiate nutrition if gut not functional
- Does
not require patient cooperation
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Disadvantage:
- Aspiration
- Impaired
absorption
- Requires
patient cooperation
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Disadvantage:
- High
infection risk (line sepsis)
- Other
catheter complications
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Timing:
- As
soon as possible to avoid gyt function problems
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Timing:
- Postresuscutation
(usually day 3)
- If
needed to supplement enteral route
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| Approach:
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Approach:
- Central
line through nonburn area
- Peripheral
line for more dilute solutions
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Route
(Enteral): The most beneficial rout is the enteral route. A
severe burn also produces gut if prior malnutrition has resulted in
dysfunction with intestinal mucosal atrophy and if enteral nutrition is
not begun, early hydrolysate with increased peptides until mucosal
function improves. Initial nutrition: a combination of enteral and
parenteral routes may be needed early in the course.
Having
defined the nutrition goals, the next issue is how to provide the
nutrients to meet those goals. Parenteral nutrition is risky but the
nutrient mix can be made to order and delivery does not require
patient participation.
Enteral
nutrition is the optimum approach but patient participation is
required which can be a major problem in the presence of pain,
agitation and sedation.
Food
intake must be guided and monitored so as to meet goals especially
protein. Injured patients usually do not select high protein foods and
food intake will not reach nutrition goals of a major burn. Nutrient
supplements must be selected carefully in order to meet nutrient goals
but decrease complications.
Commercially
available supplements in general have a high simple sugar content
(increasing risks of hyperglycemia) a high fat content and a protein
content which is usually to low for a major burn requiring adding
protein. Osmolarity must be considered to decrease hyperosmolarity
induced problems.
Finally,
palatability is a big problem. Selecting the supplement which the
patient will actually drink is of importance.
Examples
of Nutrient Supplementation
Young
patient with massive burn and respiratory distress receiving
nutrition via feeding tube. Formulation is high protein
including high content of peptides for better gut
absorption. Moderate calorie density 1 ca/cc along with
some fiber, as quantity of fluid is not a limiting
factor. Total daily volume is 2.5 liters of supplement.
Elderly
patient with moderate burn but with pre-existing involuntary
weight loss and heart disease. Supplementation of regular
meals is required to meet both calorie and demands. A
high calorie density supplement (2 cal/cc) taken orally,
limits fluid intake.
NUTRIENT SUPPLEMENTS
Numerous studies demonstrate the benefits of nutrient
supplements especially protein for restoring energy and protein
requirements in the burn patient and maintaining these requirements
during the stress phase.
The increase demands, especially if restoration of
depleted body lean mass is required usually exceed that which a
comprised patient can achieve with intake of food.
SELECTION CRITERIA
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Nutrient Supplements |
- Need for high calorie - high
protein, high protein - moderate calorie
- Quality of the contained nutrients
and macronutrients
- Nutrient mix
- Route of administration
- Complications
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Many high protein supplements are non-palatable for oral
consumption and are really used only for tube feeding. Some newer
formulations are much more palatable and can be added between
meals. In addition, all proteins are not equal. Some
proteins and their peptide content have a higher biologic value, i.e.
increased nitrogen retention, based on the their structure and
composition. In addition, specific peptides can act like growth
factors or added anabolic stimuli.
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