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.