Nutrition

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CHAPTER 27 Nutrition

I. Definition

A. Nutrition is the provision of the materials necessary to nourish the body and sustain life (Box 27-1).
B. Malnutrition is the lack of adequate intake of nutrients induced by altered dietary intake or nutrient utilization resulting from consuming too little food, lack of vital nutrients, or impaired absorption or metabolism due to disease.

1. Type

a. Marasmus

1) Reduced calorie intake
2) Extremely thin/emaciated; skin hangs on skeletal bones

b. Kwashiorkor

1) Lack of protein intake
2) Fat stores in the abdomen and face

II. Types of Delivery of Nutritional Support

A. Enteral nutrition
B. Parenteral nutrition

1. Peripheral parenteral nutrition (PPN)
2. Total peripheral nutrition (TPN)

III. Enteral Nutrition

A. Involves the gastrointestinal tract and requires a functioning small intestine
B. Oral or feeding tube

IV. Parenteral Nutrition

A. Parenteral nutrition is the use of intravenous nutrients. Patients with a nonfunctioning gastrointestinal tract receive therapy to ensure they are adequately nourished.
B. Goals

1. Maintain or restore nutritional integrity
2. Restore the body’s protein metabolism
3. Prevent malnutrition
4. Diminish rate of weight loss/maintain body weight
5. Promote wound healing
6. Replace nutritional deficits

C. Indications

1. Short bowel syndrome, massive bowel resection
2. Active inflammatory disease of the intestine
3. Severe malabsorption
4. Intractable vomiting or diarrhea
5. Severe acute pancreatitis
6. High output fistula (>500 mL/day)
7. Severe malnutrition with intolerance to enteral tube feedings
8. Enteral feeding access not possible due to upper GI obstruction
9. Enterocutaneous fistula with high output
10. Lower birth weight infants (premature)
11. Bone marrow transplant with graft versus host disease (GVHD) of the gut

D. Contraindications

1. Functional gastrointestinal tract
2. Patients do not want to eat
3. Venous access is not available
4. Awaiting flatus or bowel sounds after surgery
5. Expected duration of parenteral nutrition is less than 5 days
6. Terminal illness

a. The prognosis does not warrant the use of nutritional support (the benefits do not outweigh the risks).

E. Administration

1. PPN

a. Use of small veins in the extremities
b. Used when central line access is not available
c. Short-term use only
d. Osmolarities greater than 900 mOsm/L may irritate the peripheral vein.

1) PPN solutions must be isotonic to prevent damage to veins.

e. Glucose concentration of PPN is lower than that of central TPN.
f. Do not use in patients requiring fluid restrictions.

2. Central (TPN)

a. Use of larger veins in the trunk

1) Subclavian, internal jugular, and femoral

b. Osmolarity generally 1000–2000 mOsm/L

F. TPN components

1. Carbohydrates (dextrose)

a. Caloric value 3.4 kcal/gm
b. Maximal carbohydrate utilization

1) 4–5 mg/kg per minute; do not exceed 7 mg/kg per minute or 202–205 kcal/kg per day

c. Common dextrose TPN concentrations: 5%, 10%, 15%, 20%, 35%

2. Fats (lipid emulsion [Intralipids, Liposyn])

a. Caloric value 9 kcal/g
b. Most concentrated source of calories
c. Fat emulsions available: 10% (1.1 kcal/mL) or 20% (2.0 kcal/mL)
d. Liposyn

1) Prevents fatty acid deficiencies
2) Contains 5% safflower oil, 5% soybean oil, up to 1.2% egg phospholipids
3) In a 10% solution, each mL provides 1.1 kcal
4) Emulsion appears cloudy, with a milky appearance

e. Patients with severe egg allergies may not tolerate lipids

3. Protein (amino acids)

a. Caloric value 4 kcal/g
b. Restrict in patients with end stage renal and/or liver disease
c. Protein requirements increase depending on health of patient

1) Normal: 1 g/kg per day
2) Mild stress: 1.3 g/kg per day
3) Moderate stress (major surgery): 1.5 g/kg per day
4) Major stress (major trauma or burns): >2.0 g/kg per day

e. Ideal amino acid solution is 50:50 ratio of essential to nonessential amino acids.
f. Nitrogen balance studies dictate appropriate protein intake in critically ill patients.

1) N2 balance = N2 intake − N2 loss
2) N2 intake = grams protein consumed/24 hours/6.25
3) N2 loss = grams urine urea nitrogen + 4 (nonurinary losses)

(a) Positive N2 balance between +2 and +4 is optimal.

4. Water (30 mL/kg per day)
5. Vitamins

a. Fat-soluble vitamins: A, D, E, K
b. Water-soluble vitamins: e.g., Vitamins B1, B2, B6, B12

6. Trace minerals

a. Examples: zinc, copper, chromium, manganese and selenium

7. Electrolytes

a. Recommended maximum electrolyte concentrations per liter of standard TPN

1) Na: 130 mEq
2) K: 80 mEq
3) Mg: 8 mEq
4) Ca: 10 mEq (general estimates, the calcium-to-phosphate ratio is also important in avoiding precipitation and maintaining solution compatability)
5) Phos: 25 mM (general estimates, the calcium-to-phosphate ratio is also important in avoiding precipitation and maintaining solution compatability)

8. Some medications may be safely added to parenteral nutrition solutions.

a. H2-receptor antagonists (cimetidine, ranitidine, famotidine)
b. Insulin
c. Heparin

G. Monitoring

1. Intake and output
2. Body weight
3. Electrolytes
4. Nitrogen balance
5. Chemistry screens
6. Triglycerides
7. Complete blood count (CBC ) with differential and prothrombin time
8. Albumin level

H. Complications

1. Catheter-related

a. Pneumothorax
b. Air embolism
c. Catheter embolization
d. Venous thrombosis
e. Catheter occlusion
f. Improper location of catheter
g. Phlebitis
h. Catheter-related sepsis

2. Gastrointestinal

a. Fatty liver
b. Cholestasis
c. Gut atrophy

3. Metabolic

a. Nutrition alterations

1) Overfeeding
2) Refeeding syndrome
3) Altered mineral balance
4) Altered vitamin balance

b. Hyperglycemia
c. Rebound hypoglycemia
d. Hyperammonemia
e. Hypertriglyceridemia
f. Electrolyte imbalances

1) Sodium, normal = 135–145 mEq/L

a) Hypernatremia

(i) Causes: dehydration, diabetes insipidus, excess sodium intake
(ii) Intervention: ↑ fluid intake, ↓ sodium intake

b) Hyponatremia

(i) Causes: diuretics, excess fluid, gastrointestinal, skin, renal losses, syndrome of inappropriate antidiuretic hormone (SIADH)
(ii) Intervention: decrease fluid intake, varies depending on cause

2) Potassium, normal = 3.5–5.0 mEq/L

a) Hyperkalemia

(i) Causes: diuretics (potassium-sparing), metabolic acidosis, renal failure, insulin deficiency, chemotherapy, burns, excessive potassium intake
(ii) Intervention: ↓ potassium intake, correct metabolic acidosis, identify and correct underlying cause

b) Hypokalemia

(i) Causes: diuretics, anabolism, vomiting, diarrhea, metabolic alkalosis
(ii) Intervention: ↑ potassium intake, check for magnesium deficiency

3) Calcium, normal = 8.5–10.5 mg/dL

a) Hypercalcemia

(i) Causes: dehydration, malignancy
(ii) Intervention: ↑ fluid intake, ↓ calcium intake

b) Hypocalcemia

(i) Causes: chronic renal failure, hypoalbuminemia
(ii) Intervention: calculate estimated serum calcium concentration; correct for hypoalbuminemia; adjust calcium intake when necessary

4) Magnesium, normal = 1.5–2.0 mEq/L

a) Hypermagnesemia

(i) Causes: renal dysfunction, excessive magnesium intake
(ii) Intervention: ↓ magnesium intake, check renal function

b) Hypomagnesemia

(i) Causes: diarrhea, malabsorption, anabolism, parathyroid disease; drugs that deplete magnesium
(ii) Intervention: ↑ magnesium intake, check for refeeding syndrome

5) Phosphorus, normal = 3.0–4.5 mg/dL

a) Hyperphosphatemia

(i) Causes: renal dysfunction, hypoparathyroidism, excessive phosphorus intake, chemotherapy
(ii) Intervention: ↓ phosphorus intake, identify and treat underlying cause

b) Hypophosphatemia

(i) Causes: antacids and drugs that bind phosphorus, anabolism, phosphate-free dialysate, burn recovery, respiratory alkalosis, diabetic ketoacidosis, alcoholism
(ii) Intervention: discontinue any agents that bind phosphate, ↑ phosphorus intake, check for refeeding syndrome

Box 27-1 2005 Focus Areas of the Dietary Guidelines for Americans*

From the US Department of Health and Human Services, US Department of Agriculture: Dietary guidelines for Americans 2005: Key recommendations, Washington, DC, 2005, Authors. Retrieved March 22, 2006, from www.health.gov/dietaryguidelines/dga2005/recommendations.htm.)

1. Adequate Nutrients within Calorie Needs

• Consume a variety of nutrient-dense foods and beverages within and among the basic food groups while choosing foods that limit the intake of saturated and trans fats, cholesterol, added sugars, salt, and alcohol.
• Meet recommended intakes within energy needs by adopting a balanced eating pattern, such as the USDA Food Guide for the DASH Eating Plan.

2. Weight Management

• To maintain body weight in a healthy range, balance calories from foods and beverages with calories expended.
• To prevent gradual weight gain over time, make small decreases in food and beverage calories and increase physical activity.

3. Physical Activity

• Engage in regular physical activity and reduce sedentary activities to promote health, psychological well-being, and a healthy body weight.
• Achieve physical fitness by including cardiovascular conditioning, stretching exercises for flexibility, and resistance exercises or calisthenics for muscle strength and endurance.

4. Food Groups to Encourage

• Consume a sufficient amount of fruits and vegetables while staying within energy needs. Two cups of fruit and 2½ cups of vegetables per day are recommended for a reference 2000-calorie intake, with higher or lower amounts depending on the calorie level.
• Choose a variety of fruits and vegetables each day. In particular, select from all five vegetable subgroups (dark green, orange, legumes, starchy vegetables, and other vegetables) several times a week.
• Consume 3 or more ounce-equivalents of whole-grain products per day, with the rest of the recommended grains coming from enriched or whole-grain products. In general, at least half the grains should come from whole grains.
• Consume 3 cups per day of fat-free or low-fat milk or equivalent milk products.

5. Fats

• Consume less than 10% of calories from saturated fatty acids and less than 300 mg/day of cholesterol, and keep trans fatty acid consumption as low as possible.
• Keep total fat intake between 20% and 35% of calories, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts, and vegetable oils.
• When selecting and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low-fat, or fat-free.
• Limit intake of fats and oils high in saturated and/or trans fatty acids, and choose products low in such fats and oils.

6. Carbohydrates

• Choose fiber-rich fruits, vegetables, and whole grains often.
• Choose and prepare foods and beverages with little added sugars and caloric sweeteners, such as amounts suggested by the USDA Food Guide and the DASH Eating Plan.
• Reduce the incidence of dental caries by practicing good oral hygiene and consuming sugar- and starch-containing foods and beverages less frequently.

7. Sodium and Potassium

• Consume less than 2300 mg (approximately 1 tsp of salt) of sodium per day.
• Choose and prepare foods with little salt. At the same time, consume potassium-rich foods, such as fruits and vegetables.

8. Alcoholic Beverages

• Those who choose to drink alcoholic beverages should do so sensibly and in moderation—defined as the consumption of up to one drink per day for women and up to two drinks per day for men.
• Alcoholic beverages should not be consumed by some individuals, including those who cannot restrict their alcohol intake; women of childbearing age who may become pregnant, pregnant, and lactating women; children and adolescents; individuals taking medications that can interact with alcohol; and those with specific medical conditions.
• Alcoholic beverages should be avoided by individuals engaging in activities that require attention, skill, or coordination, such as driving or operating machinery.

9. Food Safety

• To avoid microbial foodborne illness:

image Clean hands, food-contact surfaces, and fruits and vegetables. Meat and poultry should be washed or rinsed.
image Separate raw, cooked, and ready-to-eat foods while shopping, preparing, or storing foods.
image Cook foods to a safe temperature to kill microorganisms.
image Chill (refrigerate) perishable food promptly and defrost foods properly.
image Avoid raw (unpasteurized) milk or any products made from unpasteurized milk, raw or partially cooked eggs or foods containing raw eggs, raw or undercooked meat and poultry, unpasteurized juices, and raw sprouts.

* The 2005 Dietary Guidelines remain the current guidance until the 2010 Dietary Guidelines are published.

REVIEW QUESTIONS

(Answers and Rationales on page 381.)

1. Which of the following medications may be safely added to parenteral solutions?

I. Ranitidine
II. Insulin
III. Heparin
a. I only
b. III only
c. I and II
d. II and III
e. I, II, and III

2. Which of the following statements regarding peripheral parenteral nutrition is true?

a. It is used when central line access is not available.
b. It is for long-term use only.
c. Isotonic solutions should be avoided.
d. It must be infused through a large vein, such as the superior vena cava.
e. All of the above

3. Which of the following is a possible complication of administering parenteral nutrition solutions?

I. Fatty liver
II. Hyperglycemia
III. Pneumothorax
a. I only
b. III only
c. I and II
d. II and III
e. I, II, and III

4. Renal failure may cause which of the following electrolyte imbalances?

a. Hypermagnesemia
b. Hypocalcemia
c. Hyperphosphatemia
d. Hyperkalemia
e. All of the above

5. Which of the following acronyms refer(s) to a type of parenteral nutrition?

I. PPN
II. PNM
III. TNA
a. I only
b. III only
c. I and II only
d. II and III only
e. I, II, and II

6. Parenteral administration of 1 L of 10% dextrose in water provides the patient with approximately how many kcal of energy?

a. 100–150 kcal
b. 150–200 kcal
c. 300–350 kcal
d. 400–450 kcal
e. 700–750 kcal

7. A nutritional product is said to contain 12 g of protein, 24 g of carbohydrate, and 6 g of fat in each 100-mL serving. What is the caloric content of a serving?

a. 122.4 kcal
b. 183.6 kcal
c. 177.9 kcal
d. 368.6 kcal
e. 426.2 kcal

8. What caloric density value (kcal/g) should be used when calculating the amount of amino acids in infusion solutions?

a. 4 kcal/g
b. 9 kcal/g
c. 3.4 kcal/g
d. 6.2 kcal/g
e. None of the above

9. The fatty acid emulsion, Liposyn II:

a. provides calories.
b. causes the final solution to be cloudy.
c. prevents fatty acid deficiencies.
d. contains safflower oil, soybean oil, and egg phosphatides.
e. All of the above

10. Before the patient is administered a fat emulsion such as Liposyn II, the pharmacist should determine if the patient has an allergy to:

I. eggs
II. peanuts
III. shellfish
a. I only
b. III only
c. I and II
d. II and III
e. I, II, and III

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