Fluid Electrolyte Imbalances

While obtaining an assessment and health history from a patient, which of the following statements by the patient will alert the nurse to a possible fluid volume excess?

"I have been taking some salt tablets while working outdoors in the summer, but they sure make me thirsty." A high sodium intake stimulates thirst and increased water intake. A total fluid excess occurs when water is ingested to balance sodium. The other symptoms are typical of fluid-volume deficit or other problems.

A patient who has a large amount of carbon dioxide in the blood has a:

(Large amount of carbonic acid and high hydrogen ion concentration). The amount of carbon dioxide in the blood directly relates to carbonic acid concentration and subsequently hydrogen ion concentration. The carbon dioxide combines with water in the blood to form carbonic acid, and in cases in which carbon dioxide is retained in the blood, acidosis occurs.

A patient with a pH of 7.29 has metabolic acidosis. A value that is useful in determining whether the cause of the acidosis is due to an acid gain or to a bicarbonate loss is the:

Anion gap. (Calculation of the anion gap by subtracting the serum chloride and bicarbonate levels from the serum sodium level should normally be 10 to 14 mmol/L. The anion gap is increased in metabolic acidosis associated with acid gain (e.g., diabetic acidosis) but remains normal in metabolic acidosis caused by bicarbonate loss (e.g., diarrhea).

In a patient with a positive Chvostek's sign, the nurse would anticipate the IV administration of

Calcium gluconate. (Chvostek's sign is a contraction of facial muscles in response to a tap over the facial nerve. This indicates the neuromuscular irritability of low calcium levels, and IV calcium is the treatment used to prevent laryngeal spasms and respiratory arrest.)

Symptoms of sodium imbalances are primarily manifested through altered:

Central nervous system function. As water shifts into and out of cells in response to the osmolality of the blood, the cells that are most sensitive to shrinking or swelling are those of the brain, resulting in neurologic symptoms.

CAsE study Fluid and Electrolyte Imbalance Patient Profile F.E., a 74-year-old woman who lives alone, is admitted to the hospital because of weakness and confusion. She has a history of chronic heart failure and chronic diuretic use. Objective Data • Neurologic: Confusion, slow to respond to questioning, generalized weakness • Cardiovascular: BP 90/62, HR 112 and irregular, peripheral pulses weak; ECG indicates sinus tachycardia • Pulmonary: Respirations 12/min and shallow • Additional findings: Decreased skin turgor; dry mucous membranes Significant Laboratory Results • Serum electrolytes ■ ■ ■ ■ Na+ K+ 141 mEq/L (141 mmol/L) Cl− 85 mEq/L (85 mmol/L) HCO3 43 mEq/L (43 mmol/L) 2.5 mEq/L (2.5 mmol/L) BUN 42 mg/dL (15 mmol/L) Hct 49% • Arterial blood gases pH 7.52 PaCO2 55mm Hg PaO2 88mm Hg HCO3 42 mEq/L (42 mmol/L)

Clinical decision-Making Questions 1. Status: fluid-volume deficit Physical assessment: Decreased skin turgor; dry mucous membranes; weak pulses, low blood pressure; confusion Laboratory findings: Elevated blood urea nitrogen (BUN); elevated hematocrit Status: Hypokalemia Physical assessment: Weakness, confusion; irregular heart rhythm, tachycardia Laboratory findings: potassium 2.5 mEq/L Etiology: Diuretic therapy 2. Electrocardiographic (ECG) changes are associated with hypokalemia and metabolic alkalosis. 3. Metabolic alkalosis: pH 7.52 with base bicarbonate excess (43 mEq/L) Etiology: Diuretic-induced hypokalemia is the primary factor. Compensation: Not complete because the pH is out of normal range, but increased PaCO2 and slow and shallow respirations indicate the attempt by the lungs to increase carbon dioxide to compensate for excess bicarbonate. 4. Less fluid reserve because older adults have less total body fluid; older adults also have decreased thirst sensation. 5. Aldosterone would be secreted in response to a hyperkalemia, and in her case its release would be inhibited by the hypokalemia. However, her low blood pressure and extracellular fluid deficit would stimulate secretion of aldosterone to increase sodium and water retention but cause even more potassium loss. 6. General care: Encourage and assist with oral fluid intake Provide skin care with assessment, changes in position, no soap Assessments: • Vital signs q4hr • I&O; daily weights • Cardiac monitoring until electrolytes and acid-base normal • Type and rate of IV fluid and electrolyte replacement • Lung sounds for signs of fluid overload in cardiac- compromised patient • Daily serum electrolyte and blood gas levels. 7. Nursing diagnoses: • Deficient fluid volume related to excessive extracellular fluid (ECF) loss or decreased fluid intake • Ineffective health maintenance related to lack of knowledge of drugs and preventive measures • Risk for injury related to confusion, muscle weakness • Risk for impaired skin integrity r/t dehydration. Collaborative problems: Potential complications: dysrhythmias; hypovolemic shock; hypoxemia

A patient is scheduled to have placement of a tunnelled catheter for administration of chemotherapy for breast cancer. When preparing the patient for the catheter insertion, the nurse explains that this method of administration:

Decreases the risk for extravasation at the infusion site. (Catheters tunneled to the distal end of the superior vena cava or the right atrium are vascular access devices inserted into central veins, which decrease the incidence of extravasation, provide for rapid dilution of chemotherapy, and reduce the need for venipunctures. Most right atrial catheters, except for a Groshong, need to be flushed with heparin to prevent clotting in the tubing. Regional chemotherapy administration delivers the drug directly to the tumor and is the only administration route that can decrease the systemic effects of the drugs.)

To provide free water and intracellular fluid hydration for a patient with acute gastroenteritis who is NPO, the nurse would expect administration of:

Dextrose 5% in water. Fluids such as 5% dextrose in water (D5W) allow water to move from the extracellular fluid to the intracellular fluid. Although D5W is physiologically isotonic, the dextrose is rapidly metabolized, leaving free water to shift into cells.

A patient at risk for hypernatremia is one who:

Has impaired consciousness and decreased thirst sensitivity. A major cause of hypernatremia is a water deficit, which can occur in those with a decreased sensitivity to thirst, the major protection against hyperosmolality. All other conditions lead to hyponatremia.

A patient with chronic kidney disease has:

Hyperphosphatemia. (A commonly associated electrolyte imbalance is Hypocalcemia. Kidneys are the major route of phosphate excretion, a function that is impaired in renal failure. A reciprocal exists between phosphorus and calcium, and high serum phosphate levels of kidney failure cause low calcium concentration in the serum.)

While caring for an 84-year-old patient, the nurse monitors the patient's fluid and electrolyte balance, recognizing that normal changes of aging are likely to cause:

Hyponatremia. A decrease in renin and aldosterone and an increase in ADH and atrial natriuretic peptide (ANP) lead to decreased sodium reabsorption and increased water retention by the kidney, both of which lead to hyponatremia. Skin changes lead to increased insensible water loss, and plasma oncotic pressure is more often decreased because of lack of protein intake.

A patient is taking diuretic drugs that cause sodium loss from the kidney. The fluid or electrolyte imbalance most likely to occur in this patient is:

Isotonic fluid loss. (Because of the osmotic pressure of sodium, water will be excreted with the sodium lost with the diuretic. A change in the relative concentration of sodium will not be seen, but an isotonic fluid loss will occur).

An example of an IV solution that would be appropriate to treat an extracellular fluid volume deficit is:

Lactated Ringer's solution. (An isotonic solution does not change the osmolality of the blood and does not cause fluid shifts between the extracellular fluid and intracellular fluid. In the case of extracellular fluid loss, an isotonic solution, such as lactated Ringer's solution, is ideal because it stays in the extracellular compartment. A hypertonic solution would pull fluid from the cells into the extracellular compartment, resulting in cellular fluid loss and possible vascular overload.)

Aldosterone is secreted by the adrenal cortex in response to:

Loss of sodium and water.

Hyperkalemia is frequently associated with:

Metabolic acidosis. In a metabolic acidosis, hydrogen ions in the blood are taken into the cell in exchange for potassium ions as a means of buffering excess acids. This results in an increase in serum potassium until the kidneys have time to excrete the excess potassium.

A common collaborative problem that is indicated for both hyperkalemia and hypokalemia is a:

Potential complication: dysrhythmias. (Potassium maintains normal cardiac rhythm, transmission and conduction of nerve impulses, and contraction of muscles. Cardiac cells demonstrate the most clinically significant changes with potassium imbalances because of changes in cardiac conduction. Although paralysis may occur with severe potassium imbalances, cardiac changes are seen earlier and much more commonly.)

On assessment of a central venous access device (CVAD) site, the nurse observes that the transparent dressing is loose along two sides. The nurse should:

Remove the dressing and apply a new transparent dressing using sterile technique. Greatest risk with CVAD is systemic infection. Dressings that are loose should be changed immediately to reduce this risk.