Hypernatremia is a condition in which the serum sodium concentration is greater than 145 mEq/L (normal range is 136 to 145 mEq/L). Sodium is the most abundant cation in the body; a 70-kg person has approximately 4200 mEq of sodium. About 30% of the total body sodium, called silent sodium, is bound with bone and other tissues; the remaining 70%, called the exchangeable sodium, is dissolved in the extracellular fluid (ECF) compartment or in the compartments in communication with the ECF compartment. Sodium has five essential functions: It maintains the osmolarity of the ECF; it maintains ECF volume and water distribution; it affects the concentration, excretion, and absorption of other electrolytes, particularly potassium and chloride; it combines with other ions to maintain acid-base balance; and it is essential for impulse transmission of nerve and muscle fibers.
Hypernatremia is a fairly rare electrolyte imbalance that occurs in less than 1% of all hospital admissions and is unusual in patients who are awake, are alert, and have an intact thirst response. When it does occur, mortality may be as high as 50%. Hypernatremia usually occurs when there is an excess of sodium in relation to water in the ECF compartment, resulting in hyperosmolarity of the ECF, which produces a shift in water from the cells to the ECF. The result is cellular dehydration. Three different manifestations of hypernatremia have been described, based on the ratio of total body water (TBW) to total body sodium: hypovolemic hypernatremia,
hypervolemic hypernatremia, and euvolemic hypernatremia. The cause of hypernatremia is associated with the ratio of TBW to total body sodium. In hypernatremia, there is often an excess of sodium relative to TBW.
Nursing care plan assessment and physical examination
Inquire about the patient’s daily fluid and salt intake. Patients with hypernatremia often report a decrease in fluid intake and possibly a high salt intake. Since polyuria moving to oliguria is an early sign of hypernatremia, ask about daily urine output and if the urine appears concentrated. Question the patient about fever, diarrhea, and vomiting, which might contribute to dehydration. If hypernatremia is severe, the patient may be confused. Ask the family if the patient has been lethargic, disoriented, or agitated. These changes in mental status, along with occurrence of a seizure, indicate severe hypernatremia.
Assess the patient’s vital signs; fever, tachycardia, decreased blood pressure, and orthostatic hypotension are characteristic of hypernatremia. Assess the skin and mucous membranes for signs of dehydration. With pronounced hypernatremia, expect poor skin turgor; flushed skin color; dry mucous membranes; and a rough, dry tongue. With more severe hypernatremia, assess the patient for muscle twitching, hyperreflexia, tremors, seizures, and rigid paralysis.
Assess the patient’s ability to obtain adequate fluid intake. The patient’s lethargic state contributes to the poor fluid intake. Assess the quality and support of the caregivers regarding their ability to provide for the patient’s fluid intake. Since in severe hypernatremia, the symptoms are primarily neurological, assess the patient’s level of orientation and her or his ability to communicate needs. Assess the safety needs of the patient, especially for the disoriented elderly or debilitated patient. Note that central nervous system symptoms are particularly upsetting for the patient and family and may create anxiety over the patient’s long-term prognosis.
Nursing care plan primary nursing diagnosis: Fluid volume deficit related to fluid loss, inadequate fluid intake, or fluid shifts to the extravascular space.
Nursing care plan intervention and treatment plan
The goal is to decrease the total body sodium and replace the fluid loss. Encourage liquids; if the patient cannot tolerate fluids, an intravenous (IV) hypotonic electrolyte solution (0.2% or 0.45% sodium chloride) or salt-free solution is usually ordered. Sometimes these two types of solutions are alternated to prevent hyponatremia. If 5% dextrose in water is ordered, monitor the urine output because this solution encourages diuresis, which can aggravate the hypernatremic condition. Maintain intake and output records and weigh the patient each day to monitor the fluid volume status.
Monitor the patient’s serum sodium levels daily as well to determine the effectiveness of IV fluids. Administer the water replacement slowly as prescribed to reduce the serum sodium levels not more than 2 mEq/L per hour. If hypernatremia is corrected too quickly, the ECF shifts into the cells, resulting in cerebral edema and neurological problems. Monitor the patient for signs and symptoms of cerebral edema: headache, lethargy, nausea, vomiting, widening pulse pressure, and decreased pulse rate. Sometimes, diuretic therapy is indicated to increase sodium excretion, along with a decrease of oral sodium intake in the diet. No pharmacologic management is usually required other than IV therapy. Independent
Offer fluids and water frequently to patients with hypernatremia. Avoid caffeinated fluids and alcohol because they can increase the serum sodium level by causing water diuresis. Notify the physician of any changes in mental status, such as agitation, confusion, and disorientation. If the patient is at risk for seizures, initiate seizure precautions.
Give oral care every 2 hours; avoid using lemon glycerin swabs and alcoholic mouthwashes because they have a drying effect and can cause discomfort. Monitor the condition of the skin, and assist with position changes frequently. Determine the patient’s ability to ambulate safely. If the patient is confused and disoriented, maintain the bed in the lowest position and maintain safety measures.
Nursing care plan discharge and home health care guidelines
Teach the patient and his or her caregivers the importance of an adequate fluid intake and normal sodium intake. Discuss the foods that are appropriate for a low-sodium diet, if indicated. Advise the patient or significant others to avoid over-the-counter medications that are high in sodium. Teach the patient about the early signs of hypernatremia: polyuria, nausea, vomiting, and orthostatic hypotension. Explain that as hypernatremia becomes severe, the patient or family will note changes in the patient’s mental status. Encourage the patient or significant others to notify the primary healthcare provider if any of these signs and symptoms occur.