ECF volume excess causes an expansion of the ECF compartment. The primary cause of ECF excess is cardiovascular dysfunction. FVE is always secondary to an increase in total body sodium content, which causes total body water increase. Normally, the posterior pituitary decreases secretion of the ADH when excess water moves into the cells. This causes the kid- ney to eliminate excess fluid. However, if a patient has excessive secretion of ADH, the water will be retained, which places the patient at risk for FVE. Excessive secretion of ADH can be caused by fear, pain, and postop- erative reaction 12 to 24 hours after surgery, along with acute infections. Etiology
Conditions that cause overhydration include excessive administration of oral or I.V. fluids containing sodium, excessive irrigation of body cavities or organs, and use of hypotonic fluids to replace isotonic fluid loss. When sodium and water are retained in the same proportion, iso-osmolar FVE occurs. Edema is commonly associated with excess extracellular body fluid or excess fluid due to I.V. overhydration. Physiological factors lead- ing to edema may be caused by various clinical conditions, such as heart failure (HF), kidney failure, cirrhosis of the liver, steroid excess, and reten- tion of sodium (Kee, Paulanka, & Polek, 2010).
COMMONCAUSES OFISOTONICOVERHYDRATION
■ Renal failure leading to decreased excretion of water and sodium
■ HF leading to stasis of blood in the circulation and venous congestion
■ Excess fluid intake of isotonic I.V. solutions
■ High corticosteroid levels as a result of therapy, stress response, or disease causing sodium and water retention
■ High aldosterone levels (stress response to adrenal dysfunction, liver damage, or metabolic problems)
COMMONCAUSES OFHYPOTONICOVERHYDRATION(WATERINTOXICATION)
■ More fluid is gained than solute
■ Serum osmolality falls, causing cells to swell (cerebral cells most sensitive)
■ Repeated plain water enemas
■ Overuse of hypotonic I.V. fluids
■ In young children or infants, ingestion of inappropriately prepared formula and/or excess water (use of water bottle as pacifier)
■ SIADH causes kidneys to retain large amounts of water without sodium.
Clinical Manifestations
Clinically, ECF volume excess has distinct signs and symptoms, the most prominent being weight gain. A constant irritating nonproductive cough is frequently the first clinical symptom of hypervolemia. It is caused by excess fluid “backed up” into the lungs.
Edema usually is not apparent until 2 to 4 kg of fluid has been retained. Alterations in respiratory and cardiovascular function are present and include hypertension and tachycardia. Moist crackles in the lung usually in- dicate that the lungs are congested with fluid. Cyanosis is a late symptom of pulmonary edema resulting from hypervolemia. In addition to having the common assessment findings, some patients experience confusion, altered LOC, skeletal muscle weakness, and increased bowel sounds.
Peripheral edema present in the morning may result from inadequate cardiac, hepatic, or renal function. Peripheral edema in the evening may result from fluid stasis or dependent edema. An increase in vascular vol- ume may be evidenced by distended neck veins, slow-emptying periph- eral veins, a full and bounding pulse, and an increase in CVP.
NOTE
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Azotemia (increased nitrogen levels in the blood) can occur with FVE when urea and creatinine are not excreted because of de- creased perfusion by the kidneys and excretion of wastes (Smeltzer, Bare, Hinkle, & Cheever, 2010).Laboratory Findings
Laboratory findings are variable and usually nonspecific.
■ BUN, serum protein, albumin, hemoglobin, and hematocrit may be decreased as a result of hemodilution.
■ Serum osmolality will be decreased below 280 mOsm/kg.
■ B-type natriuretic peptide (BNP) is increased to greater than 100 pg/mL in congestive HF.
■ Serum sodium is decreased if hypervolemia occurs as a result of excessive water retention.
■ Urine specific gravity is decreased if kidney is attempting to excrete excess volume.
NURSING FAST FACT!
Peripheral edema should be assessed in the morning before the patient gets out of bed. A weight gain of 2.2 lb is equivalent to the retention of 1 L of body water.
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NURSING FAST FACT!
Severe or prolonged isotonic FVE in a person with a healthy heart and kidneys usually is compensated by increasing urinary output.
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NURSING POINTS OF CARE
HYPERVOLEMIA (FVE)
Nursing Assessments
■ Complete a client history to identify underlying health problems that may have contributed to FVE.
■ Obtain dietary history that emphasizes sodium, protein, and water intake.
■ Assess vital signs; focus on the presence of a bounding pulse.
■ Assess for constant irritating cough, difficulty in breathing, neck and hand vein engorgement, and lung crackles.
■ Assess I&O at regular intervals to identify excessive fluid retention.
■ Assess acute weight gain of 2.2 lb (1 kg) using serial daily weights.
■ Assess extremities for peripheral edema (feet and ankles in ambu- latory patients, and sacral region in patients confined to bed).
Treatment
Medical management is directed toward sodium and fluid restriction, admin- istration of diuretics, and treatment of the underlying cause (Porth & Matfin, 2010). The treatment of FVE focuses on providing a balance between sodium and water I&O. Diuretic therapy is commonly used to increase sodium elimi- nation. If renal function is so severely impaired that pharmacological agents cannot act efficiently, hemodialysis or peritoneal dialysis may be considered to remove nitrogenous wastes, control potassium and acid–base balance, and re- move sodium and fluid (Smeltzer, Bare, Hinkle, & Cheever, 2010). Table 3-4 summarizes the fluid imbalances of hypovolemia and hypervolemia.
Key Nursing Interventions
1. Monitor vital signs; report elevated BP or bounding pulse to LIP. 2. Monitor weight daily. Check (serial) weight every morning before
breakfast.
3. Observe for the presence of edema daily. Check for pitting edema in the extremities every morning.
4. Monitor diet, and teach appropriate food selections to avoid excess salt.
5. Encourage rest periods to support diuresis.
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Table 3-4 QUICK ASSESSMENT GUIDE FOR FLUID IMBALANCES Signs and Symptoms of Area of Clinical Signs and Symptoms of Fluid Fluid Volume Excess Assessment Volume Deficit (Hypovolemia) (Hypervolemia) NeurologicalCardiovascular
Respiratory
Irritability, restlessness, lethargy, confusion (seizures and coma) Thirst
Frank or postural hypotension Tachycardia
Weak, thready pulses Decreased pulse volume Cool extremities with delayed
capillary refill Flat neck veins
Poor peripheral vein filling Central venous pressure (CVP)
<4 cm Lungs clear
Respirations may be rapid and shallow
Confusion
Galloping heart rhythm (heart S3sound) in adults
Distended neck veins Slow emptying hand veins CVP >11 cm
Bounding full pulse Peripheral edema
Tachypnea (>20) and dyspnea Irritated cough
Hacking cough, becoming moist and productive Labored breathing Wet lung sounds (moist
crackles)
Decreased O2saturation
Skin Appearance and Temperature
Eyes
Lips Oral Cavity
Urine Volume and Concentration Body Weight
Diagnostic Laboratory Findings
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Table 3-4 QUICK ASSESSMENT GUIDE FOR FLUID IMBALANCES—cont’dSigns and Symptoms of Area of Clinical Signs and Symptoms of Fluid Fluid Volume Excess Assessment Volume Deficit (Hypovolemia) (Hypervolemia)
Low-grade fever Dry skin “tenting”
Sunken or depressed fontanels in infants
Decreased tearing and dry conjunctiva
Sunken eyeballs Dry lips, cracked Dry
Increased tongue furrows, tongue coated
Sticky mucous membranes Concentrated urine and low
volume <30 mL/hr Specific gravity high: >1.035 Weight loss
5%: Mild deficit
5%–10%: Moderate deficit >15%: Severe deficit (especially
important in children) Normal or high hematocrit and
blood urea nitrogen (BUN) Serum osmolarity elevated: >300 Serum sodium >150 mEq
Serum glucose elevated: >120 mg/dL
Bulging fontanels in children <18 months Edematous skin (1+ to 4+) Periorbital edema No change No change Polyuria Specific gravity <1.005 Weight gain (acute and
rapid) 5%: Mild excess
5%–10%: Moderate excess >15%: Severe excess Hematocrit and BUN
decreased
Serum osmolality low: <275 Serum sodium low: <125 mEq
Sources: Kee, Paulanka & Polek, (2010); Porth & Matfin, (2010).