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THE
BURN NUTRITION MODULE
Section
VIII
What
are the standard clinical monitors used to assess adequacy of
nutrition?
-
Assessment
of energy, protein needs using Standardized Nutritional
Protocols
-
Daily
weights
-
Calorie
intake and protein intake counts
-
Calorimetry
(usually weekly)
-
Nitrogen
balances when indicated
-
Net
nitrogen loss should not exceed 5grams/day
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The basic
principles of nutritional management have been presented. However,
it is essential that nutritional support be monitored and adjusted
as needed to maintain goals and minimize complications.
Standard
monitors must be in place. Of extreme importance in managing burns
is that nutritional protocols, as standards of care, must be
present. Metabolism and Nutrition are key components of body
function and require a well designed program of management.
This
program includes the monitoring of energy and protein needs. Daily
weights, calorie and protein intakes, indirect calorimetry weekly as
well as nitrogen balance measures especially if there is evidence of
excessive weight loss or symptoms of excess lean mass loss.
What
are the standard laboratory tests used to monitor nutrition?
- Electrolytes
including potassium, magnesium and phosphate (major
shifts occur post burn)
- Blood
urea nitrogen, creatinine (a marker of catabolism
relative to renal function)
- Blood
glucose (hyperglycemia - a common problem)
- Liver
profile (monitoring CHOLESTASIS)
- Triglycerides
(monitoring adequacy of fat clearance; adjust fat
intake)
- Prealbumin
and Transferrin, a marker of anabolism and catabolism
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Because of the major metabolic changes
post burn and further alterations with nutrition, standard laboratory
tests are needed to maintain homeostasis and detect complications.
Major electrolyte shifts occur with burn injury and nutrition. The
intracellular electrolytes, magnesium and phosphate level
characteristically decrease to very low levels with onset of nutrition
as cell mass increases. Increased provision of key electrolytes is
needed to avoid major complications. Hypernatremia can indicate
inadequate hydration. Blood urea nitrogen typically increases with
protein breakdown but the level must be assessed relative to
creatinine (renal function). An elevated BURN is also a marker of
inadequate hydration.
Blood glucose
is a key monitor since hyperglycemia is a characteristic of burn
injury. Glucose intake and insulin use must be carefully adjusted.
Liver function abnormalities are common especially increasing alkaline
phosphates. A rapidly rising level may indicate excess fat deposition
(which often means overfeeding).
Serum
triglycerides measure adequacy of fat clearance and should not exceed
250mg/dl. If elevated, fat intake should be decreased. Prealbumin and
Transferrin are markers of protein synthesis and degradation. A
continually decreasing value usually reflects inadequate protein
intake.
What
clinical changes should initiate a nutrition adjustment?
-
An
excessive and progressive weight loss (need to
increase calories and micronutrients)
-
Evidence
of an excessive lean mass loss e.g.. weakness,
poor healing of wounds, grafts, donors (assess
nitrogen balance, likely increase protein and
micronutrients)
- Evidence
of excess CO2 production reflecting
excess carbohydrates (adjust CHO intake)
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Evidence of
inadequate energy intake would be a progressive weight loss exceeding
that predicted by the degree of injury. A reassessment of calorie
needs should be done with a likely increase in both calories and
micronutrients.
Also
progressive weakness, unexpected poor healing of the wound, grafts and
donor sites would indicate the need for increased protein (check
nitrogen balance). Check also for specific micronutrient deficiencies.
Finally, an excessive CO2 production would indicate
excessive carbohydrate intake which needs to be adjusted. Measuring a
respiratory quotient would make the diagnosis. An RQ exceeding 1.0 is
an indicator of excessive carbohydrates.
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