Chapter 21
Nutrition Assessment
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Learning Objectives
• Describe how a comprehensive nutrition
assessment is conducted.
• Describe how to calculate and interpret body
mass index.
• Describe how to distinguish two forms of proteinenergy malnutrition from each other.
• List the biochemical indicators of nutritional
status.
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Learning Objectives (cont.)
• State what to observe clinically in the
malnourished patient.
• Describe how to obtain and evaluate a nutrition
history.
• Describe how to estimate daily resting energy
expenditure.
• List the indications, contraindications, hazards,
and limitations of indirect calorimetry.
• Describe how to properly prepare a patient for
indirect calorimetry.
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Learning Objectives (cont.)
• Describe how to interpret the results of indirect
calorimetry.
• Describe how REE values are adjusted to reflect
a patient’s actual energy needs.
• State the effects of malnutrition and on the
respiratory system.
• Describe how to identify patients at high risk for
malnutrition.
• Identify the effect on a patient of too much
protein, carbohydrate, or fat.
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Learning Objectives (cont.)
• State when enteral nutrition and parenteral
nutrition are needed.
• Describe how to identify and minimize the
common respiratory complications of enteral
feedings.
• State specific nutritional guidelines that apply to
patients with a specific pulmonary disease.
• Explain how common pulmonary medications
affect nutrition.
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Nutrition Assessment
• Process of collecting & evaluating data to
determine nutritional status of patient
• Performed by registered dietician or physician
trained in clinical nutrition
• Compares social, pharmaceutical,
environmental, physical, & medical factors to
evaluate nutrient needs of patient
• Done to develop nutrition care plan
• Data is collected from anthropometrics,
biochemical tests, & clinical observations
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The ABCDs of nutritional assessment include all of
the following:
A. Airway, breathing, circulation, and defibrillation
B. Assessment (physical), BMI calculation, caloric
count, and diet (intake/output)
C. Anthropometric, biochemical tests, clinical
observations, and dietary analyses
D. Albumin, Bilirubin, Creatinine, and Deoxycortisol
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Anthropometrics
• Refers to measurements of body
 Height & weight
 Skinfold thickness
 Arm muscle measurements
 Waist & hip measurements
 Head circumference
 Wrist diameter
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Anthropometrics (cont.)
• Height & weight
 Usually measured to determine weight status using
body mass index (BMI) & ideal body weight (IBW)
 BMI between 18.5 & 24.9 kg/m2 for adults is
considered healthy
 BMI of 25 to 29.9 kg/m2 = overweight
 BMI > 30 kg/m2 = obese
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BMI Categories
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BMI Categories
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Anthropometrics (cont.)
• Ideal Body Weight:
 Ideal body weight may also be determined using
Hamwi formulas:
• Men: 106 pounds for first 5 feet, plus 6 pounds for each inch
over 5 feet
• Women: 100 pounds for first 5 feet, plus 5 pounds for each
inch over 5 feet
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The IBW for a 25 year-old female patient whose
height is measured at 5'5" would be:
A. 155 lb.
B. 125 lb.
C. 100 lb.
D. 130 lb.
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Anthropometrics (cont.)
• Kwashiorkor & marasmus
 Marasmus - typically seen in children ages 6 to18
months in deprived areas of world chronically
malnourished
 Kwashiorkor results from more sudden lack of protein &
calories in infant (seen as protruding belly & edematous
face)
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Weight Classification According to BMI
• Healthy weight:
 BMI between 18.5 & 24.9 for adults or BMI-for-age
between 10th & 85th percentiles for children
• Overweight:
 BMI 25.0 to 29.9 in adult & BMI-for-age in children
between 85th & 95th percentiles
• Obesity:
 BMI greater than 30 in adults & greater than 95th
percentile in boys & girls ages 2 to 20 years
• Underweight:
 BMI of less than 18.5; underweight children score in
bottom 10th percentile for BMI-for-age
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Biochemical Indicators
• Albumin measured for long-term trends in
nutrition because it has half-life of 21 days
• Transthyretin has half-life of 2 to 3 days &
therefore responds to nutritional changes much
quicker than albumin
• Total lymphocyte count may be reduced with
malnutrition due to lack of protein intake
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Biochemical Indicators (cont.)
• Creatinine-height index measures amount of
creatinine excreted in urine over 24 hours
 60% to 80% of normal = mild deficit of muscle mass
 40% to 60% = moderate deficit
 <40% = severe depletion of muscle mass
• Nitrogen balance used to assess protein
balance because 16% of protein is nitrogen
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Biochemical indicators are important element of
nutritional assessment because:
A. They are use to determine ideal body weight
B. Can predict nutritional outcomes
C. Indicate the level of protein synthesis in the
body
D. Help to calculate predicted body weight
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Pulmonary Function
• Protein malnutrition has been linked to reduced
function of diaphragm & other muscles of
breathing
• Leading to reduced vital capacity & peak
inspiratory pressures
• Represents significant problem in ICU when
trying to wean patient from mechanical
ventilation
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Clinical Indicators
• Examination of hair, eyes, lips, mouth & gums,
skin, & nails provides clinical indication of
nutritional status
• Chronically malnourished patient will appear
thin; appearance of protruding ribs; patient is
cachexic in such cases
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Common Dietary Measures
•
•
•
•
•
24-hour recall
Usual intake recall
Food diary or food record
Food frequency questionnaire
Evaluation of nutrition history
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All of the following are economic benefits of a
well-designed, multidisciplinary nutritional
intervention plan, except:
A. Decreased nosocomial infections
B. Reduced hospital stays
C. Reduced need for medication or medical care
D. Increased years of productivity
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Macronutrients & Energy Requirements
• Macronutrients supply the body’s energy
requirements:
 Protein
 Carbohydrate
 Fat
• Classic measure of energy expenditure is basal
metabolic rate (BMR)
• Alternatively, predictive equations like HarrisBenedict Equation can be used to estimate daily
resting energy expenditure (REE)
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Indirect Calorimetry
• Estimation of energy
expenditure (caloric
needs) by
measurement of O2
consumption & CO2
production
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Indirect Calorimetry
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Interpretation of Calorimetry (cont.)
• Results are used to assess metabolic status &
plan nutritional support
• First step is to compare results to predicted
normal using Harris-Benedict equations
• Resting energy expenditure (REE) >10% above
normal indicate hypermetabolic state
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Interpretation of Calorimetry (cont.)
• REE results <90% of normal predicted indicate
hypometabolism
• Next, interpret RQ, which is ratio of CO2
produced to O2 consumed
• RQ of carbohydrates = 1.0; protein = 0.82; & fat
= 0.7.
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Interpretation of Calorimetry (cont.)
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During indirect calorimetry a steady-state condition
is reached when:
A. Patient remains still for 1 minute
B. REE results are within normal limits
C. No artifacts are detected during the test
D. Five consecutive 1-min averages have a
variability of 5% or less
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Nutritional Support
• Malnutrition results from insufficient energy
(calorie) intake over time
• Protein-energy malnutrition (PEM) has adverse
effects on patient’s immune system & on
respiratory musculature
• PEM can be result of starvation or disease
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Respiratory Impairment & Malnutrition
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Respiratory Consequences of
Malnutrition
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Providing Substrates
• Protein should provide about 20% of patient’s
caloric needs
• Carbohydrates should provide about 50% of
patient’s caloric needs
• Fat should provide about 20% to 30% of
patient’s caloric needs
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Routes of Feeding
• Enteral (oral & tube feeding) feeding is route of
choice; safer, healthier, & easier than parenteral
route
• Potential complication of enteral feeding is
aspiration
• Parenteral (intravenous) feeding can be done
through peripheral or central vein
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Pulmonary Patient
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All of the following can help decrease the risk of
pulmonary aspiration for tube-fed patients, except:
A. Aspiration of subglottic secretions
B. Endotracheal intubation
C. Keep head of bed at 45 degree angle
D. Placement of feeding tube beyond the pylorus
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