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 protein-energy 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

Anthropometrics

• Refers to measurements of bodyHeight & weightSkinfold thicknessArm muscle measurementsWaist & hip measurementsHead circumference Wrist diameter

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Anthropometrics (cont.)

• Height & weightUsually 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 healthyBMI of 25 to 29.9 kg/m2 = overweightBMI > 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.

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 hours60% to 80% of normal = mild deficit of muscle mass40% 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

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

Macronutrients & Energy Requirements

• Macronutrients supply the body’s energy requirements:ProteinCarbohydrateFat

• Classic measure of energy expenditure is basal metabolic rate (BMR)

• Alternatively, predictive equations like Harris-Benedict 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

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