CALCULATION OF NUTRITIONAL NEEDS
Nutritional needs include the need for energy, the need for protein, and the need for hydration, with vitamins and electrolytes part of the essential requirements.
ENERGY NEEDS
Energy requirements are assessed in a variety of ways. The Harris-Benedict formula has for many years been considered the criterion standard for predicting calorie requirements in acutely ill hospitalized patients, although it may overestimate energy needs.
The formula is outlined in the following sample calculations:
HARRIS-BENEDICT FORMULA
(Basal energy expenditure [BEE]) X (activity factor) X (injury factor) - BEE is estimated by sex using the following formula:
Males: 66.5 + 13.8(wt) + 5.0(ht) - 6.8(age)
Females: 655.1 +9.6(wt) + 1.8(ht) - 4.7(age)
Activity factor
Chair- or bedbound – 1.2
Out of bed – 1.3
Injury factor
Anabolism – 1.5
Burn – 1.5-2.1
Cancer – 1.1-1.45
Closed head injury – 1.3
Elective surgery - 1.0-1.1
Fever – 1.2 per 1 degree (>37° C)
Major surgery - 1.6
Mild infection – 1.2
Moderate infection – 1.4
Multiple long bone fractures – 1.1-1.3
Sepsis – 1.2-1.4
Starvation – 0.7
Low stress – 1.3
Medium stress – 1.5
High stress – 2.0
PROTEIN NEEDS
The following factors need to be considered when estimating protein needs:
Metabolic rate
Body protein reserves
Calorie intake
Nutritional status
Disease state
Stress associated with critical illness
Age
Two ways to determine protein needs based on stress levels follow.
FORMULAS BASED ON STRESS
Blackburn's General Guide for Protein Needs Based on Stress Level
Cerra's Guide for Protein Needs Based on Stress Level
Disease States and Protein Requirements
HYDRATION OR FLUID NEEDS
This must be addressed within each nutritional assessment because it effects lab interpretation and nutritional intervention. Several methods exist to determine fluid requirements.
Fluid Requirements