Foundations of Nutrition and Nursing Care

Nursing Tip: Nitrogen Balance A positive nitrogen balance occurs when nitrogen intake equals or exceeds output, used for building and repairing tissue. A negative nitrogen balance occurs during infection, sepsis, burns, or trauma, where the body is breaking down more protein than it is consuming.

Nutrition Throughout the Lifespan

Nutritional requirements shift as a person moves through different developmental stages:

• Infancy: Characterized by rapid growth requiring high protein, vitamins, and minerals. Breast milk and formula typically provide approximately $20 \text{ kcal/oz}$.
• Toddlers and School-age: Toddlers may exhibit "picky eating" behaviors, while school-age children face an increased risk for high intake of fats, sugars, and salts.
• Adolescents: This group is at high risk for erratic eating patterns and eating disorders due to concerns regarding body image and appearance.
• Young and Middle Adults: As physical activity levels may change and metabolic rates often decline, there is an increased risk for obesity.
• Older Adults: Metabolic rates slow, decreasing overall energy needs, though requirements for vitamins and minerals remain unchanged.

Clinical Alert: Malnutrition in Older Adults Older adults are at high risk for malnutrition due to factors such as fixed incomes, fatigue, difficulty chewing, loneliness, or grief.

Nursing Assessment and Risk Factors

Nurses must identify patients at risk for altered nutrition. Patients may have an increased demand for nutrients due to fever, infection, cancer, or wound healing. Conversely, they may have a decreased ability to utilize nutrients due to GI obstructions, diabetes, cognitive changes, or impaired swallowing (dysphagia).

Hospitalized patients are particularly vulnerable; approximately $40\text{--}55\%$ are malnourished or at risk due to disrupted habits, medications, or medical procedures.

Gordon’s Functional Health Patterns: Nutritional/Metabolic

When assessing a patient, nurses should collect both subjective and objective data:

1. Subjective Data (What the patient tells you):

• Food likes/dislikes and usual diet at home.
• Reports of nausea, dysphagia, or anorexia.
• Alcohol use (type, amount, and frequency).

2. Objective Data (What you observe/measure):

• Nutritional/Metabolic Inspection: Skin color, texture, and turgor; mucous membranes; hair, nails, and teeth; presence of edema; and cognitive status.
• Anthropometric Measurements: Height, weight, and Body Mass Index (BMI).
• Laboratory Values:
  • Serum Albumin: A key indicator of protein intake and loss (Normal: $3.5\text{--}5.5 \text{ g/dL}$). Low levels suggest malnourishment.
  • Blood Urea Nitrogen (BUN): Measures urea concentration; elevated levels may suggest increased protein metabolism or renal issues.
  • Glucose: Used to evaluate carbohydrate metabolism and diabetes.

Calculating Weight Loss

Significant weight loss is a red flag for malnutrition. Nurses should monitor the percentage of body weight lost over time:

$\text{Percentage of Weight Loss} = \frac{\text{Weight Lost}}{\text{Total Weight Prior to Loss}} \times 100$

Example: A patient weighs $150 \text{ lbs}$ and lost $25 \text{ lbs}$ in one month. $\text{Prior Weight} = 150 + 25 = 175 \text{ lbs}$ $\text{Percentage Loss} = \frac{25}{175} = 0.1428 \times 100 = 14.3\%$ This represents a severe weight loss for a one-month period.

Special Nutritional Interventions

When oral intake is insufficient or impossible, nurses must manage alternative feeding methods.

Enteral Nutrition (Tube Feeding)

Enteral feeding involves delivering nutrients via the GI tract through a tube.

• Nasogastric (NG) Tube: Used for short-term feeding in patients with adequate gastric emptying.
• Gastrostomy/Jejunostomy Tubes: Surgically placed for long-term support ($>6\text{--}8$ weeks).

Nursing Interventions for Enteral Feeding:

• Verify Placement: Always obtain X-ray confirmation of tube placement before administering any food or medication.
• Positioning: Keep the patient upright at $>30$ degrees (ideally $45$ degrees) to prevent aspiration.
• Monitoring: Check gastric residual volume (GRV) as ordered and monitor for nausea, cramping, or vomiting.

Parenteral Nutrition (TPN)

Total Parenteral Nutrition (TPN) is a highly concentrated solution of glucose, amino acids, electrolytes, vitamins, and lipids delivered intravenously. It is reserved for patients with a nonfunctioning GI tract or those requiring extended bowel rest.

Exam Alert: TPN and Glucose Because TPN contains high concentrations of dextrose (glucose), patients are at high risk for hyperglycemia. Nurses must monitor blood glucose levels closely, even in patients without a history of diabetes.