Notes on Fluid and Electrolytes 4 FLUID VOLUME DEFICIT

FLUID VOLUME DEFICIT

A. Description
1. Dehydration occurs when the fluid intake of the body is not sufficient to meet the fluid needs of the body.
2. The goal of treatment is to restore fluid volume, replace electrolytes as needed, and eliminate the cause of the fluid volume deficit.

B. Types of fluid volume deficits
1. Isotonic dehydration
a. Water and dissolved electrolytes are lost in equal proportions.
b. Known as hypovolemia, isotonic dehydration is the most common type of dehydration.
c. Isotonic dehydration results in decreased circulating blood volume and inadequate tissue perfusion.

2. Hypertonic dehydration
a. Water loss exceeds electrolyte loss.
b. The clinical problems that occur result from alterations in the concentrations of specific plasma electrolytes.
c. Fluid moves from the intracellular compartment into the plasma and interstitial fluid spaces, causing cellular dehydration and shrinkage.

3. Hypotonic dehydration
a. Electrolyte loss exceeds water loss.
b. The clinical problems that occur result from fluid shifts between compartments, causing a decrease in
plasma volume.
c. Fluid moves from the plasma and interstitial fluid spaces into the cells, causing a plasma volume deficit and causing the cells to swell.

C. Causes of fluid volume deficits
1. Isotonic dehydration
a. Inadequate intake of fluids and solutes
b. Fluid shifts between compartments
c. Excessive losses of isotonic body fluids

2. Hypertonic dehydration—conditions that increase fluid
loss, such as excessive perspiration, hyperventilation,
ketoacidosis, prolonged fevers, diarrhea, early-stage
renal failure, and diabetes insipidus

3. Hypotonic dehydration
a. Chronic illness
b. Excessive fluid replacement (hypotonic)
c. Renal failure
d. Chronic malnutrition

D. Assessment
1. Cardiovascular
a. Thready, increased pulse rate
b. Decreased blood pressure and orthostatic (postural) hypotension
c. Flat neck and hand veins in dependent positions
d. Diminished peripheral pulses

2. Respiratory: Increased rate and depth of respirations

3. Neuromuscular
a. Decreased central nervous system activity, from lethargy to coma
b. Fever

4. Renal
a. Decreased urinary output
b. Increased urinary specific gravity

5. Integumentary
a. Dry skin
b. Poor turgor, tenting present
c. Dry mouth

6. Gastrointestinal
a. Decreased motility and diminished bowel sounds
b. Constipation
c. Thirst
d. Decreased body weight

7. Hypotonic dehydration: skeletal muscle weakness

8. Hypertonic dehydration
a. Hyperactive deep tendon reflexes
b. Pitting edema

9. Laboratory findings
a. Increased serum osmolality
b. Increased hematocrit
c. Increased blood urea nitrogen (BUN) level
d. Increased serum sodium level

E. Interventions
1. Monitor cardiovascular, respiratory, neuromuscular, renal, integumentary, and gastrointestinal status.
2. Prevent further fluid losses and increase fluid compartment volumes to normal ranges.
3. Provide oral rehydration therapy if possible and intravenous (IV) fluid replacement if the dehydration is
severe; monitor intake and output.
4. Generally, isotonic dehydration is treated with isotonic fluid solutions, hypertonic dehydration with hypotonic fluid solutions, and hypotonic dehydration with hypertonic fluid solutions.
5. Administer medications as prescribed such as antidiarrheal, antimicrobial, antiemetic, and antipyretic
medications, to correct the cause and treat any symptoms.
6. Administer oxygen as prescribed.
7. Monitor electrolyte values and prepare to administer medication to treat an imbalance, if present.

Notes on Fluid and Electrolytes 3: FLUID VOLUME EXCESS

FLUID VOLUME EXCESS

A. Description
1. Fluid intake or fluid retention exceeds the fluid needs of the body.
2. Fluid volume excess also is called overhydration or fluid overload.
3. The goal of treatment is to restore fluid balance, correct electrolyte imbalances if present, and eliminate or control the underlying cause of the overload.

B. Types
1. Isotonic overhydration
a. Known as hypervolemia, isotonic overhydration results from excessive fluid in the extracellular fluid compartment.
b. Only the extracellular fluid compartment is expanded, and fluid does not shift between the extracellular and
intracellular compartments.
c. Isotonic overhydration causes circulatory overload and interstitial edema; when severe or when it occurs in a client with poor cardiac function, congestive heart
failure and pulmonary edema can result.

2. Hypertonic overhydration
a. Occurrence of hypertonic overhydration is rare and is caused by an excessive sodium intake.
b. Fluid is drawn from the intracellular fluid compartment; the extracellular fluid volume expands, and the intracellular fluid volume contracts.

3. Hypotonic overhydration
a. Hypotonic overhydration is known as water intoxication.
b. The excessive fluid moves into the intracellular space, and all body fluid compartments expand.
c. Electrolyte imbalances occur as a result of dilution.

C. Causes
1. Isotonic overhydration
a. Inadequately controlled IV therapy
b. Renal failure
c. Long-term corticosteroid therapy

2. Hypertonic overhydration
a. Excessive sodium ingestion
b. Rapid infusion of hypertonic saline
c. Excessive sodium bicarbonate therapy

3. Hypotonic overhydration
a. Early renal failure
b. Congestive heart failure
c. Syndrome of inappropriate antidiuretic hormone secretion
d. Inadequately controlled IV therapy
e. Replacement of isotonic fluid loss with hypotonic fluids
f. Irrigation of wounds and body cavities with hypotonic fluids

D. Assessment
1. Cardiovascular
a. Bounding, increased pulse rate
b. Elevated blood pressure
c. Distended neck and hand veins
d. Elevated central venous pressure

2. Respiratory
a. Increased respiratory rate (shallow respirations)
b. Dyspnea
c. Moist crackles on auscultation

3. Neuromuscular
a. Altered level of consciousness
b. Headache
c. Visual disturbances
d. Skeletal muscle weakness
e. Paresthesias

4. Integumentary
a. Pitting edema in dependent areas
b. Skin pale and cool to touch

5. Increased motility in the gastrointestinal tract

6. Isotonic overhydration results in liver enlargement and ascites.

7. Hypotonic overhydration results in the following:
a. Polyuria
b. Diarrhea
c. Nonpitting edema
d. Dysrhythmias
e. Projectile vomiting
8. Laboratory findings
a. Decreased serum osmolality
b. Decreased hematocrit
c. Decreased BUN level
d. Decreased serum sodium level
e. Decreased urine specific gravity

E. Interventions
1. Monitor cardiovascular, respiratory, neuromuscular, renal, integumentary, and gastrointestinal status.
2. Prevent further fluid overload, and restore normal fluid balance.
3. Administer diuretics; osmotic diuretics typically are prescribed first to prevent severe electrolyte imbalances.
4. Restrict fluid and sodium intake.
5. Monitor intake and output and weight.
6. Monitor electrolyte values, and prepare to administer medication to treat an imbalance if present.

Notes on Fluids and Electrolytes Part 1

This Notes on Fluids and Electrolytes (1) focus primarily on the assessment of a fluid and electrolyte imbalance, interventions, and evaluating the expected outcomes. Fluids and electrolytes constitute a content area that is sometimes complex and difficult to understand. The nurse must understand cell functions and properties and the concepts related to body fluids as outlined in this chapter. It focuses on the common fluid and electrolyte disturbances. As you review this content, focus on the Pyramid Points related to the causes, assessment findings, and related treatments. In any fluid or electrolyte imbalance, nursing interventions include monitoring significant laboratory results and monitoring the client's cardiovascular, respiratory, gastrointestinal, neuromuscular, renal, and central nervous system status. Integrated Processes addressed in this chapter are Caring, Communication and Documentation, Nursing Process, and Teaching/Learning.

Important Terms

calcium
A mineral element needed for the process of bone formation, coagulation of blood, excitation of cardiac and skeletal muscle, maintenance of muscle tone, conduction of neuromuscular impulses, and the synthesis and regulation of the endocrine and exocrine glands. The normal adult level is 8.6 to 10.0 mg/dL.

fluid volume deficit
Dehydration in which the fluid intake of the body is not sufficient to meet the fluid needs of the body.

fluid volume excess
Fluid intake or fluid retention that exceeds the fluid needs of the body. Also called overhydration or fluid overload.

homeostasis
The tendency of biological systems to maintain relatively constant conditions in the internal environment while continuously interacting with and adjusting to changes originating within or outside the system.

hypercalcemia
A serum calcium level that exceeds 10.0 mg/dL.

hyperkalemia
A serum potassium level that exceeds 5.1 mEq/L.

hypermagnesemia
A serum magnesium level that exceeds 2.6 mg/dL.

hypernatremia
A serum sodium level that exceeds 145 mEq/L.

hyperphosphatemia
A serum phosphorus level that exceeds 4.5 mg/dL.

hypocalcemia
A serum calcium level less than 8.6 mg/dL.

hypokalemia
A serum potassium level less than 3.5 mEq/L.

hypomagnesemia
A serum magnesium level less than 1.6 mg/dL.

hyponatremia
A serum sodium level less than 135 mEq/L.

hypophosphatemia
A serum phosphorus level less than 2.7 mg/dL.

magnesium
Concentrated in the bone, cartilage, and within the cell itself; required for the use of adenosine triphosphate (ATP) as a source of energy. It is necessary for the action of numerous enzyme systems such as carbohydrate metabolism, protein synthesis, nucleic acid synthesis, and contraction of muscular tissue. It
also regulates neuromuscular activity and the clotting mechanism. The normal adult level is 1.6 to 2.6 mg/dL.

potassium
A principle electrolyte of intracellular fluid and the primary buffer within the cell itself. It is needed for nerve conduction, muscle function, acid-base balance, and osmotic pressure. Along with calcium and magnesium, it controls

sodium
An abundant electrolyte that maintains osmotic pressure and acid-base balance and transmits nerve impulses. The normal adult level is 135 to 145 mEq/L.