Nutritional Alterations

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Nutritional Alterations

Linda D. Urden

Objectives

Implications of Undernutrition for the Sick or Stressed Patient

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Be sure to check out the bonus material, including free self-assessment exercises, on the Evolve web site at

evolve.elsevier.com/Urden/priorities/.

Although illness or injury is the major factor contributing to development of malnutrition, other possible contributing factors are lack of communication among the nurses, physicians, and dietitians responsible for the care of these patients; frequent diagnostic testing and procedures, which lead to interruption in feeding; medications and other therapies that cause anorexia, nausea, or vomiting and thereby interfere with food intake; insufficient monitoring of nutrient intake; and inadequate use of supplements, tube feedings, or total parenteral nutrition (TPN) to maintain the nutritional status of these patients.

Nutritional status tends to deteriorate during hospitalization unless appropriate nutrition support is started early and continually reassessed. Malnutrition in hospitalized patients is associated with a wide variety of adverse outcomes. Wound dehiscence, pressure ulcers, sepsis, infections, respiratory failure requiring ventilation, longer hospital stays, and death are more common among malnourished patients.13 Decline in nutritional status during hospitalization is associated with higher incidences of complications, increased mortality rates, increased length of stay, and higher hospital costs.

Assessing Nutritional Status

A nutrition screening should be conducted on every patient. A brief questionnaire to be completed by the patient or significant other, the nursing admission form, or the physician’s admission note usually provides enough information to determine whether the patient is at nutritional risk (Box 6-1). Any patient judged to be nutritionally at risk needs a more thorough nutrition assessment.

Nutrition support is the provision of specially formulated or delivered oral, enteral, or parenteral nutrients to maintain or restore optimal nutrition status.4 The nutrition assessment can be performed by or under the supervision of a registered dietitian or by a nutrition care specialist (e.g., nurse with specialized expertise in nutrition). Figure 6-1 shows the route of administration of specialized nutrition support.

Biochemical Data

A wide range of laboratory tests can provide information about nutritional status. Those most often used in the clinical setting are described in Table 6-1. No diagnostic tests for evaluation of nutrition are perfect, and care must be taken in interpreting the results of the tests.5

TABLE 6-1

COMMON BLOOD AND URINE TESTS USED IN NUTRITION ASSESSMENT

TEST COMMENTS/LIMITATIONS
Serum Proteins Levels decrease with protein deficiency but also in liver failure; albumin levels are slow to change in response to malnutrition and repletion; prealbumin levels fall in response to trauma and infection
Albumin or prealbumin
Hematologic Values  
Anemia
Normocytic (normal MCV, MCHC) Common with protein deficiency
Microcytic (decreased MCV, MCH, MCHC) Indicative of iron deficiency (can be from blood loss)
Macrocytic (increased MCV) Common in folate and vitamin B12 deficiency
Lymphocytopenia Common in protein deficiency

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MCV, mean corpuscular volume; MCHC, mean corpuscular hemoglobin concentration; MCH, mean corpuscular hemoglobin.

Clinical or Physical Manifestations

A thorough physical examination is an essential part of nutrition assessment. Box 6-2 lists some of the more common findings that may indicate an altered nutritional state. It is especially important for the nurse to check for signs of muscle wasting, loss of subcutaneous fat, skin or hair changes, and impairment of wound healing.

Diet and Health History

Information about dietary intake and significant variations in weight is a vital part of the history. Dietary intake can be evaluated in several ways, including a diet record, a 24-hour recall, and a diet history. Other information to include in a nutrition history is listed in Box 6-3.

Evaluating Nutrition Assessment Findings

It is rare for a patient to exhibit a lack of only one nutrient. Nutritional deficiencies usually are combined, with the patient lacking adequate amounts of protein, calories, and possibly vitamins and minerals. A common form of combined nutritional deficit among hospitalized patients is protein calorie malnutrition (PCM). Two types of PCM are kwashiorkor and marasmus.

Kwashiorkor results in low levels of the serum proteins albumin, transferrin, and prealbumin; low total lymphocyte count; impaired immunity; loss of hair or hair pigment; edema resulting from low plasma oncotic pressure caused by a loss of plasma proteins; and an enlarged, fatty liver. Marasmus is recognizable by weight loss, loss of subcutaneous fat, and muscle wasting. In the marasmic person, creatinine excretion in the urine is low, an indication of reduced muscle mass. Because PCM weakens muscles, increases vulnerability to infection, and can prolong hospital stays, the health care team should diagnose this serious disorder as quickly as possible so that an appropriate nutrition intervention can be implemented.

Determining Nutritional Needs

Calorie and protein needs of patients are often estimated using formulas that provide allowances for increased nutrient use associated with injury and healing. Although indirect calorimetry is considered the most accurate method to determine energy expenditure, estimates using formulas have demonstrated reasonable accuracy.6,7 Some rules of thumb are available to provide a rough estimate of caloric needs so that nurses and other caregivers can quickly determine if patients are being seriously overfed or underfed (Table 6-2).

TABLE 6-2

ESTIMATING ENERGY NEEDS

CATEGORY DESCRIPTION CALORIES/KG CALORIES/LB
Obese More than 40% over ideal body weight or BMI >30 21 9.5
Sedentary Relatively inactive individual without regular aerobic exercise; hospitalized patient without severe injury or sepsis 25-30 11-13.5
Moderate activity or injury Individual obtaining regular aerobic exercise plus routine activities; patient with trauma or sepsis 30-35 13.5-16
Very active or severe injury Manual laborer or athlete in very active training; patient with major burns or trauma 40 18

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The goal of nutrition assessment is to obtain the most accurate estimate of nutritional requirements. Underfeeding and overfeeding must be avoided during critical illness. Overfeeding results in excessive production of carbon dioxide, which can be a burden in the person with pulmonary compromise. Overfeeding increases fat stores, which can contribute to insulin resistance and hyperglycemia. Hyperglycemia increases the risk of postoperative infections in diabetic and nondiabetic individuals.810 Hyperglycemia is a complication to be avoided if possible.

Nutrition and Cardiovascular Alterations

Diet and cardiovascular disease may interact in a variety of ways. On the one hand, excessive nutrient intake, manifested by overweight or obesity and a diet rich in cholesterol and saturated fat, is a risk factor for development of arteriosclerotic heart disease. On the other hand, the consequences of chronic myocardial insufficiency may include malnutrition.

Nutrition Assessment in Cardiovascular Alterations

A nutrition assessment provides the nurse and other members of the health care team the information necessary to plan the patient’s nutrition care and education. Common findings in the nutrition assessment of the cardiovascular patient are summarized in Box 6-4. The major nutritional concerns relate to appropriateness of body weight and the levels of serum lipids and blood pressure.

Nutrition Intervention in Cardiovascular Alterations

Myocardial Infarction

The following guidelines will assist the nurse in providing appropriate nutritional care for the patient in the immediate post-myocardial infarction period:

Hypertension

A substantial number of individuals with hypertension are “salt sensitive,” with their disorder improving when sodium intake is limited. Therefore restriction of sodium intake, usually to 2.5 g/day or less, is often advised to help control hypertension.11 One teaspoon of salt provides about 2.3 g of sodium. Most salt substitutes contain potassium chloride and may be used with the physician’s approval by the patient who has no renal impairment. A diet rich in fruits, vegetables, and low-fat dairy products (the DASH, or Dietary Approaches to Stopping Hypertension, diet) combined with a sodium restriction is often more effective than sodium restriction alone.12

Heart Failure

Nutrition intervention for the patient with heart failure is designed to reduce fluid retained within the body and thus reduce the preload. Because fluid accompanies sodium, limitation of sodium is necessary to reduce fluid retention. Specific interventions include limiting salt intake, usually to 5 g/day or less, and limiting fluid intake as appropriate. If fluid is restricted, the daily fluid allowance is usually 1.5 to 2 L/day, to include both fluids in the diet and those given with medications and for other purposes.

Cardiac Cachexia

The severely malnourished cardiac patient often develops heart failure. Therefore sodium and fluid restriction, as previously described, is appropriate. It is important to concentrate nutrients into as small a volume as possible and to serve small amounts frequently, rather than three large meals daily. The individual should be encouraged to consume calorie-dense foods and supplements. Good choices include meats and poultry, cheeses, yogurt, frozen yogurt, and ice cream.

Because the patient is likely to tire quickly and to suffer from anorexia, enteral tube feeding may be necessary. Typical tube feeding formulas provide 1 calorie per milliliter (cal/ml), but more concentrated products are available to provide adequate nutrients in a smaller volume. The nurse must monitor the fluid status of these patients carefully when they are receiving nutrition support. Assessing breath sounds and observing for presence and severity of peripheral edema and changes in body weight are performed daily or more frequently. A consistent weight gain of more than 0.11 to 0.22 kg (0.25 to 0.5 lb) per day usually indicates fluid retention rather than gain of fat and muscle mass.

Nutrition and Pulmonary Alterations

Malnutrition has extremely adverse effects on respiratory function, decreasing surfactant production, diaphragmatic mass, vital capacity, and immunocompetence. Patients with acute respiratory disorders find it difficult to consume adequate oral nutrients and can rapidly become malnourished. Individuals who have an acute illness superimposed on chronic respiratory problems are also at high risk. Almost three fourths of patients with chronic obstructive pulmonary disease (COPD) have had weight loss. Patients with undernutrition and end-stage COPD, however, often cannot tolerate the increase in metabolic demand that occurs during refeeding. In addition, they are at significant risk for development of cor pulmonale and may fail to tolerate the fluid required for delivery of enteral or parenteral nutrition support. Prevention of severe nutritional deficits, rather than correction of deficits once they have occurred, is important in nutritional management of these patients.

Nutrition Assessment in Pulmonary Alterations

Common findings in nutrition assessment related to pulmonary alterations are summarized in Box 6-5. The patient with respiratory compromise is especially vulnerable to the effects of fluid volume excess and must be assessed continually for this complication, particularly during enteral and parenteral feeding.

Nutrition Intervention in Pulmonary Alterations

Prevent or Correct Undernutrition/Underweight

The nurse and dietitian work together to encourage oral intake in the undernourished or potentially undernourished patient who is capable of eating. Small, frequent feedings are especially important because a very full stomach can interfere with diaphragmatic movement. Mouth care should be provided before meals and snacks to clear the palate of the taste of sputum and medications. Administering bronchodilators with food can help to reduce the gastric irritation caused by these medications.

Because of anorexia, dyspnea, debilitation, or need for ventilatory support, however, many patients will require enteral tube feeding or TPN. It is especially important for the nurse to be alert to the risk of pulmonary aspiration in the patient with an artificial airway. To reduce the risk of pulmonary aspiration during enteral tube feeding, the nurse should (1) keep the patient’s head elevated at least 45 degrees during feedings, unless contraindicated; (2) discontinue feedings 30 to 60 minutes before any procedures that require lowering the head; (3) keep the cuff of the artificial airway inflated during feeding, if possible; (4) monitor the patient for increasing abdominal distention; and (5) check tube placement before each feeding (if intermittent) or at least every 4 to 8 hours if feedings are continuous.

Avoid Overfeeding

Overfeeding increases the production of carbon dioxide (CO2). This is unlikely to be significant in the patient who is eating foods. Instead, it is an iatrogenic complication of TPN or enteral feeding. Arterial CO2 tension (PaCO2) may rise sufficiently to make it difficult to wean a patient from the ventilator. A balanced regimen with both lipids and carbohydrates providing the nonprotein calories is optimal for the patient with respiratory compromise, and the patient needs to be reassessed continually to ensure that caloric intake is not excessive.

Prevent Fluid Volume Excess

Pulmonary edema and failure of the right side of the heart, which may be precipitated by fluid volume excess, further worsen the status of the patient with respiratory compromise. Maintaining careful intake and output records allows for accurate assessment of fluid balance. Usually the patient requires no more than 35 to 40 ml/kg/day of fluid. For the patient receiving nutrition support, fluid intake can be reduced by (1) using 20% or 30% lipid emulsions as a source of calories, (2) using tube feeding formulas providing at least 2 cal/ml (the dietitian can recommend appropriate formulas), and (3) choosing oral supplements that are low in fluid.

Nutrition and Neurologic Alterations

Because neurological disorders such as stroke and closed head injury tend to be long-term problems, these patients require good nutritional care to prevent nutritional deficits and promote well-being.

Nutrition Assessment in Neurological Alterations

Nutrition-related assessment findings vary widely in the patient with neurological alterations, depending on the type of disorder present (Box 6-6).

Nutrition Intervention in Neurological Alterations: Prevent or Correct Nutrition Deficits

Oral Feedings

Patients with dysphagia or weakness of the swallowing musculature often experience the greatest difficulty in swallowing dry foods and thin liquids (e.g., water) that are difficult to control.

Tube Feedings and Total Parenteral Nutrition

Patients who are unconscious or unable to eat because of severe dysphagia, weakness, ileus, or other reasons require tube feedings or TPN. Prompt initiation of nutrition support must be a priority in the patient with neurological impairment. Needs for protein and calories are increased by infection and fever, as in the patient with encephalitis or meningitis. Needs for protein, calories, zinc, and vitamin C are increased during wound healing, as in trauma patients and those with pressure ulcers.

Patients with neurological deficits have an increased risk of certain complications (particularly pulmonary aspiration) during tube feeding and therefore require especially careful nursing management. Patients of most concern are (1) those with an impaired gag reflex, such as some patients with cerebrovascular accident (stroke); (2) those with delayed gastric emptying, such as patients in the early period after spinal cord injury and patients with head injury treated with barbiturate coma; and (3) those likely to experience seizures. To help prevent pulmonary aspiration, the patient’s head is kept elevated, if not contraindicated; when elevation of the head is not possible, administering feedings with the patient in the prone or lateral position will allow free drainage of emesis from the mouth and decrease the risk of aspiration.

Administering phenytoin with enteral formulas decreases the absorption of the drug and the peak serum level achieved and thus may increase the risk of seizures. The phenytoin dosage must be adjusted appropriately. Phenytoin levels should be monitored carefully in patients receiving enteral feedings.13

Hyperglycemia is a common complication in patients receiving corticosteroids. Regular monitoring of blood glucose is an important part of their care. They may require insulin to control the hyperglycemia.

Prompt use of nutrition support is especially important for patients with head injuries because head injury causes marked catabolism, even in patients who receive barbiturates, which should decrease metabolic demands. Head-injured patients rapidly exhaust glycogen stores and begin to use body proteins to meet energy needs, a process that can quickly lead to PCM. The catabolic response is partly a result of corticosteroid therapy in head-injured patients. However, the hypermetabolism and hypercatabolism are also caused by dramatic hormonal responses to this type of injury.14 Levels of cortisol, epinephrine, and norepinephrine increase as much as seven times normal. These hormones increase the metabolic rate and caloric demands, causing mobilization of body fat and proteins to meet the increased energy needs. Furthermore, head-injured patients undergo an inflammatory response and may be febrile, creating increased needs for protein and calories. Improvement in outcome and reduction in complications have been observed in head-injured patients who receive adequate nutrition support early in the hospital course.15

Nutrition and Renal Alterations

Providing adequate nutrition care for the patient with renal disease can be extremely challenging. Although renal disturbances and their treatments can greatly increase needs for nutrients, necessary restrictions in intake of fluid, protein, phosphorus, and potassium make delivery of adequate calories, vitamins, and minerals difficult. Thorough nutrition assessment provides the basis for successful nutrition management in patients with renal disease.

Nutrition Assessment in Renal Alterations

Some common assessment findings in individuals with renal disease are listed in Box 6-7.

Nutrition Intervention in Renal Alterations

The goal of nutrition intervention is to administer adequate nutrients, including calories, protein, vitamins, and minerals, while avoiding excesses of protein, fluid, electrolytes, and other nutrients with potential toxicity.

Protein