8
Fluids and Electrolytes
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C H AP T E R
PRIORITY CONCEPTS Cellular Regulation; Fluid and Electrolytes
CRITICAL THINKING What Should You Do?
The nurse notes the presence of U waves on a client’s cardiac
monitor screen. What actions should the nurse take?
Answer located on p. 91.
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I. Concepts of Fluid and Electrolyte Balance
A. Electrolytes
1. Description: An electrolyte is a substance that, on
dissolving in solution, ionizes; that is, som e of
its m olecules split or dissociate into electrically
charged atom s or ions (Box 8-1).
2. Measurem ent
a. The m etric system is used to m easure volum es
of fluids—liters (L) or m illiliters (m L).
b . The unit of m easure that expresses the com binin g activity of an electrolyte is the
m illiequivalen t (m Eq).
c. One m illiequivalent (1 m Eq) of any cation
always reacts chem ically with 1 m Eq of
an anion.
d . Milliequivalen ts provide inform ation about
the num ber of anions or cation s available
to com bine with other anion s or cation s.
B. Body fluid com partm ents (Fig. 8-1)
1. Description
a. Fluid in each of the body com partm ents contains electrolytes.
b . Each com partm ent has a particular com position of electrolytes, which differs from that of
oth er com partm ents.
c. To fun ction norm ally, body cells m ust have
fluids and electrolytes in the right com partm ents and in the right am ounts.
d . Whenever an electrolyte m oves out of a
cell, anoth er electrolyte m oves in to take
its place.
e. The num bers of cation s and anions m ust be
the sam e for homeostasis to exist.
f. Com partm en ts are separated by sem iperm eable m em branes.
2. Intravascular com partm ent: Refers to fluid inside
a blood vessel
3. Intracellular com partm ent
a. The intracellular com partm ent refers to all
fluid inside the cells.
b . Most bodily fluids are inside the cells.
4. Extracellular com partm ent
a. Refers to fluid outside the cells.
b . The extracellular com partm ent includes the
interstitial fluid, which is fluid between cells
(som etim es called the third space), blood,
lym ph, bon e, connective tissue, water, and
transcellular fluid.
C. Third-spacing
1. Third-spacing is the accum ulation and sequestration of trapped extracellular fluid in an actual or
potential body space as a result of disease or
injury.
2. The trapped fluid represents a volum e loss and is
unavailable for norm al physiological processes.
3. Fluid m ay be trapped in body spaces such as the
pericardial, pleural, periton eal, or joint cavities;
the bowel; or the abdom en, or within soft tissues
after traum a or burns.
4. Assessing the intravascular fluid loss caused by
third-spacing is difficult. The loss m ay not be
reflected in weight chan ges or intake and output
records, and m ay not becom e apparen t until
after organ m alfunction occurs.
D. Edem a
1. Edem a is an excess accum ulation of fluid in
the interstitial space; it occurs as a result of
alterations in oncotic pressure, hydrostatic pressure, capillary perm eability, and lym phatic
obstruction.
2. Localized edem a occurs as a result of traum atic
injury from accidents or surgery, local inflam m atory processes, or burns.
3. Generalized edem a, also called anasarca, is an
excessive accum ulation of fluid in the interstitial
CHAPTER 8 Fluids and Electrolytes
Properties of Electrolytes and Their Components
Molecule
A molecule is 2 or more atoms that combine to form a
substance.
Intrac e llular fluid
(70%)
Extrac e llular fluid
(30%)
Inte rs titia l
Intrava s cula r
(22%)
(6%)
Tra ns ce llula r
(2%)
(ce re bros pina l
ca na ls,
lympha tic tis s ue s,
s ynovia l joints,
a nd the eye )
FIGURE 8-1 Distribution of fluid by compartments in the average adult.
space throughout the body and occurs as a result
of conditions such as cardiac, renal, or liver
failure.
E. Body fluid
1. Description
a. Body fluids transport nutrients to the cells and
carry waste products from the cells.
b . Total body fluid (intracellular and extracellular) am ounts to about 60% of body weight in
the adult, 55% in the older adult, and 80% in
the infant.
c. Thus infants and older adults are at a higher
risk for fluid-related problem s than younger
adults; children have a greater proportion of
body water than adults and the older adult
has the least proportion of body water.
A cation is an ion that has given away or lost electrons and
therefore carries a positive charge.
The result is fewer electrons than protons, and the result is a
positive charge.
Anion
An anion is an ion that has gained electrons and therefore
carries a negative charge.
When an ion has gained or taken on electrons, it assumes a negative charge and the result is a negatively charged ion.
2. Con stituents of body fluids
a. Body fluids consist of water and dissolved
substances.
b . The largest single fluid constituent of the
body is water.
c. Som e substances, such as glucose, urea, and
creatinine, do not dissociate in solution; that
is, they do not separate from their com plex
form s into sim pler substances when they
are in solution .
d . Other substances do dissociate; for exam ple,
when sodium chloride is in a solution , it dissociates, or separates, into 2 parts or elem en ts.
Infants and older adults need to be monitored
closely for fluid imbalances.
F. Body fluid transport
1. Diffusion
a. Diffusion is the process whereby a solute
(substance that is dissolved) m ay spread
through a solution or solven t (solution in
which the solute is dissolved).
b . Diffusion of a solute spreads the m olecules
from an area of higher concentration to an
area of lower concentration.
c. A perm eable m em brane allows substances to
pass through it without restriction.
d . A selectively perm eable m em brane allows
som e solutes to pass through without restriction but prevents oth er solutes from passin g
freely.
e. Diffusion occurs within fluid com partm ents
and from one com partm ent to another if
the barrier between the com partm ents is perm eable to the diffusing substances.
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Cation
d
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An ion is an atom that carries an electrical charge because it has
gained or lost electrons.
Some ions carry a negative electrical charge and some carry a
positive charge.
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An atom is the smallest part of an element that still has the
properties of the element.
The atom is composed of particles known as the proton (positive charge), neutron (neutral), and electron (negative
charge).
Protons and neutrons are in the nucleus of the atom; therefore,
the nucleus is positively charged.
Electrons carry a negative charge and revolve around the
nucleus.
As long as the number of electrons is the same as the number of
protons, the atom has no net charge; that is, it is neither positive nor negative.
Atoms that gain, lose, or share electrons are no longer neutral.
s
Ion
Atom
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BOX 8-1
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UNIT III Nursing Sciences
2. Osm osis
a. Osm otic pressure is the force that draws the
solvent from a less concentrated solute
through a selectively perm eable m em brane
into a m ore concentrated solute, thus tending
to equalize the concentration of the solvent.
b . If a m em brane is perm eable to water but not
to all solutes present, the m em brane is a selective or sem iperm eable m em brane.
c. Osm osis is the m ovement of solvent m olecules across a m em brane in response to a concentration gradient, usually from a solution of
lower to one of higher solute concentration.
d . When a m ore concentrated solution is on
one side of a selectively perm eable m em brane
and a less concentrated solution is on the
oth er side, a pull called osmotic pressure draws
the water through the m em brane to the m ore
concentrated side, or the side with m ore
solute.
3. Filtration
a. Filtration is the m ovem ent of solutes and solvents by hydrostatic pressure.
b . The m ovem ent is from an area of higher pressure to an area of lower pressure.
4. Hydrostatic pressure
a. Hydrostatic pressure is the force exerted by
the weight of a solution.
b . When a difference exists in the hydrostatic
pressure on two sides of a m em brane, water
and diffusible solutes m ove out of the solution that has the higher hydrostatic pressure
by the process of filtration.
c. At the arterial end of the capillary, the hydrostatic pressure is higher than the osm otic pressure; therefore, fluids and diffusible solutes
m ove out of the capillary.
d . At the venous end, the osm otic pressure, or
pull, is higher than the hydrostatic pressure,
and fluids and som e solutes m ove into the
capillary.
e. The excess fluid and solutes rem ainin g in the
interstitial spaces are returned to the intravascular com partm ent by the lym ph channels.
5. Osm olality
a. Osm olality refers to the num ber of osm otically active particles per kilogram of water;
it is the concentration of a solution .
b . In the body, osm otic pressure is m easured in
m illiosm oles (m Osm ).
c. The norm al osm olality of plasma is 275295 m Osm /kg (275-295 m m ol/kg).
G. Movem ent of body fluid
1. Description
a. Cell m em branes separate the interstitial fluid
from the intravascular fluid.
b . Cell m em branes are selectively perm eable;
that is, the cell m em brane and the capillary
2.
3.
4.
5.
wall allow water and som e solutes free passage through them .
c. Several forces affect the m ovem ent of water
and solutes through the walls of cells and capillaries; for exam ple, the greater the num ber
of particles within the cell, the m ore pressure
exists to force the water through the cell m em brane out of the cell.
d . If the body loses m ore electrolytes than fluids,
as can happen in diarrhea, then the extracellular fluid contains fewer electrolytes or less
solute than the intracellular fluid.
e. Fluids and electrolytes m ust be kept in balance for health; when they rem ain out of balance, death can occur.
Isoton ic solution s
a. When the solutions on both sides of a selectively perm eable m em brane have establish ed
equilibrium or are equal in concentration,
they are isotonic.
b . Isoton ic solution s are isotonic to hum an
cells, and thus very little osm osis occurs; isotonic solution s have the sam e osm olality as
body fluids.
c. Refer to Chapter 13, Table 13-1, for a list of
isotonic solution s.
Hypoton ic solutions
a. When a solution contains a lower concentration of salt or solute than another,
m ore concentrated solution, it is considered
hypotonic.
b . A hypoton ic solution has less salt or m ore
water than an isoton ic solution; these solutions have lower osm olality than body fluids.
c. Hypoton ic solutions are hypotonic to the
cells; therefore, osm osis would continue in
an attem pt to bring about balance or equality.
d . Refer to Chapter 13, Table 13-1, for a list of
hypotonic solutions.
Hypertonic solutions
a. A solution that has a higher concentration of
solutes than another, less concentrated solution is hypertonic; these solutions have a
higher osm olality than body fluids.
b . Refer to Chapter 13, Table 13-1, for a list of
hypertonic solutions.
Osm otic pressure
a. The am ount of osm otic pressure is determ ined
by the concentration of solutes in solution .
b . When the solutions on each side of a selectively perm eable m em brane are equal in concentration, they are isoton ic.
c. A hypotonic solution has less solute than an
isotonic solution, whereas a hypertonic solution contains m ore solute.
d . A solvent m oves from the less concentrated
solute side to the m ore concentrated solute
side to equalize concentration.
Fluid intake
Fluid o utput
Inge s te d wa te r
1200-1500 mL
Inge s te d food
800-1100 mL
Me ta bolic oxida tion
TOTAL
300 mL
2300-2900 mL
Kidneys
1500 mL
Ins e ns ible los s
through s kin
600-800 mL
Ins e ns ible los s
through lungs
400-600 mL
Ga s trointe s tina l tra ct
100 mL
TOTAL
2600-3000 mL
FIGURE 8-2 Sources of fluid intake and fluid output.
The client with diarrhea is at high risk for a fluid and
electrolyte imbalance.
I. Maintaining fluid and electrolyte balance
1. Description
a. Homeostasis is a term that indicates the relative stability of the intern al environ m ent.
b . Con centration and com position of body
fluids m ust be nearly constant.
c. When one of the substances in a client is deficient—either fluids or electrolytes—the substance must be replaced normally by the
intake of food and water or by therapy such as
intravenous (IV) solutions and medications.
d . When the client has an excess of fluid or electrolytes, therapy is directed toward assisting
the body to elim inate the excess.
2. The kidneys play a m ajor role in controlling balance in fluid and electrolytes.
3. The adrenal glands, through the secretion of
aldosterone, also aid in controlling extracellular
fluid volum e by regulating the am ount of
sodium reabsorbed by the kidn eys.
4. Antidiuretic horm one from the pituitary gland
regulates the osm otic pressure of extracellular
fluid by regulating the am ount of water reabsorbed by the kidn eys.
II. Fluid Volume Deficit
A. Description
1. Dehydration occurs when the fluid intake of the
body is not sufficient to m eet the fluid needs of
the body.
2. The goal of treatm ent is to restore fluid volum e,
replace electrolytes as needed, and elim inate the
cause of the fluid volum e deficit.
B. Types of fluid volum e deficits
1. Isotonic dehydration
a. Water and dissolved electrolytes are lost in
equal proportions.
b . Known as hypovolemia, isotonic dehydration
is the m ost com m on type of dehydration.
c. Isotonic dehydration results in decreased circulating blood volum e and inadequate tissue
perfusion.
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g. Severe diarrhea results in the loss of large
quan tities of fluids and electrolytes.
h . The kidn eys play a m ajor role in regulating
fluid and electrolyte balance and excrete the
largest quan tity of fluid.
i. Norm al kidn eys can adjust the am ount of
water and electrolytes leavin g the body.
j. The quantity of fluid excreted by the kidneys is
determined by the amount of water ingested
and the amount of waste and solutes excreted.
k. As long as all organ s are functioning norm ally, the body is able to m aintain balance
in its fluid content.
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6. Active transport
a. If an ion is to m ove through a m em brane
from an area of lower concentration to an
area of higher concentration, an active tran sport system is necessary.
b . An active tran sport system m oves m olecules
or ions against concentration and osm otic
pressure.
c. Metabolic processes in the cell supply the
en ergy for active transport.
d . Substances that are transported actively
through the cell m em brane include ions of
sodium, potassium, calcium, iron, and hydrogen; som e of the sugars; and the am ino acids.
H. Body fluid intake and output (Fig. 8-2)
1. Body fluid intake
a. Water enters the body through 3 sources—
orally ingested liquids, water in foods, and
water form ed by oxidation of foods.
b . About 10 m L of water is released by the
metabolism of each 100 calories of fat, carbohydrates, or protein s.
2. Body fluid output
a. Water lost through the skin is called insensible
loss (the individual is unaware of losing
that water).
b . The amount of water lost by perspiration varies
according to the tem perature of the environm ent and of the body, but the average am ount
of loss by perspiration alone is 100 m L/day.
c. Water lost from the lungs is called insensible
loss and is lost through expired air that is saturated with water vapor.
d . The am ount of water lost from the lungs varies with the rate and the depth of respiration.
e. Large quan tities of water are secreted into the
gastrointestinal tract, but alm ost all of this
fluid is reabsorbed.
f. Alarge volume of electrolyte-containing liquids
moves into the gastrointestinal tract and then
returns again to the extracellular fluid.
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CHAPTER 8 Fluids and Electrolytes
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UNIT III Nursing Sciences
2. Hypertonic dehydration
a. Water loss exceeds electrolyte loss.
b . The clin ical problem s that occur result from
alterations in the concentrations of specific
plasm a electrolytes.
c. Fluid m oves from the intracellular com partm ent into the plasma and interstitial fluid
spaces, causing cellular deh ydration and
shrin kage.
3. Hypotonic dehydration
a. Electrolyte loss exceeds water loss.
b . The clin ical problem s that occur result from
fluid shifts between com partm ents, causing
a decrease in plasm a volum e.
c. Fluid m oves from the plasm a and interstitial
fluid spaces into the cells, causing a plasm a
volum e deficit and causing the cells to swell.
C. Causes of fluid volum e deficits
1. Isoton ic dehydration
a. Inadequate intake of fluids and solutes
b . Fluid shifts between com partm ents
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 kidney disease, and diabetes
insipidus
3. Hypoton ic dehydration
a. Chronic illness
b . Excessive fluid replacem ent (hypotonic)
c. Kidney disease
d . Chronic malnutrition
D. Assessm ent (Table 8-1)
E. Interven tions
TABLE 8-1 Assessment Findings: Fluid Volume Deficit and Fluid Volume Excess
Fluid Volume Deficit
Cardiovascular
▪ Thready, increased pulse rate
▪ Decreased blood pressure and orthostatic (postural)
hypotension
▪ Flat neck and hand veins in dependent positions
▪ Diminished peripheral pulses
▪ Decreased central venous pressure
▪ Dysrhythmias
Respiratory
▪ Increased rate and depth of respirations
▪ Dyspnea
Neuromuscular
▪ Decreased central nervous system activity, from
lethargy to coma
▪ Fever, depending on the amount of fluid loss
▪ Skeletal muscle weakness
Renal
▪ Decreased urine output
Integumentary
▪ Dry skin
▪ Poor turgor, tenting
▪ Dry mouth
Gastrointestinal
▪ Decreased motility and diminished bowel sounds
▪ Constipation
▪ Thirst
▪ Decreased body weight
Laboratory Findings
▪ Increased serum osmolality
▪ Increased hematocrit
▪ Increased blood urea nitrogen (BUN) level
▪ Increased serum sodium level
▪ Increased urinary specific gravity
Fluid Volume Excess
▪ Bounding, increased pulse rate
▪ Elevated blood pressure
▪ Distended neck and hand veins
▪ Elevated central venous pressure
▪ Dysrhythmias
▪ Increased respiratory rate (shallow respirations)
▪ Dyspnea
▪ Moist crackles on auscultation
▪ Altered level of consciousness
▪ Headache
▪ Visual disturbances
▪ Skeletal muscle weakness
▪ Paresthesias
▪ Increased urine output if kidneys can compensate; decreased urine output if kidney
damage is the cause
▪ Pitting edema in dependent areas
▪ Pale, cool skin
▪ Increased motility in the gastrointestinal tract
▪ Diarrhea
▪ Increased body weight
▪ Liver enlargement
▪ Ascites
▪ Decreased serum osmolality
▪ Decreased hematocrit
▪ Decreased BUN level
▪ Decreased serum sodium level
▪ Decreased urine specific gravity
III. Fluid Volume Excess
A. Description
1. Fluid intake or fluid retention exceeds the fluid
needs of the body.
2. Fluid volum e excess is also called overhydration or
fluid overload.
3. The goal of treatm ent is to restore fluid balan ce,
correct electrolyte im balances if present, and
elim inate or control the underlying cause of
the overload.
B. Types
1. Isotonic overhydration
a. Known as hypervolemia, isoton ic overhydration results from excessive fluid in the extracellular fluid com partm ent.
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 edem a; when severe
or when it occurs in a clien t with poor cardiac
fun ction, heart failure and pulm onary edem a
can result.
2. Hypertonic overhydration
a. The occurrence of hypertonic overhydration
is rare and is caused by an excessive sodium
intake.
b . Fluid is drawn from the intracellular fluid
com partm ent; the extracellular fluid volum e
expands, and the intracellular fluid volum e
contracts.
3. Hypotonic overhydration
a. Hypotonic overhydration is known as water
intoxication.
b . The excessive fluid m oves into the intracellular space, and all body fluid com partm ents
expand.
c. Electrolyte im balances occur as a result of
dilution.
A client with acute kidney injury or chronic kidney
disease is at high risk for fluid volume excess.
IV. Hypokalemia
A. Description
1. Hypokalem ia is a serum potassium level lower
than 3.5 m Eq/L (3.5 m m ol/L) (Box 8-2).
2. Potassium deficit is potentially life-threaten ing
because every body system is affected.
BOX 8-2
Potassium
Normal Value
3.5 to 5.0 mEq/ L (3.5 to 5.0 mmol/ L)
Common Food Sources
Avocado, bananas, cantaloupe,
tomatoes
Carrots, mushrooms, spinach
Fish, pork, beef, veal
Potatoes
Raisins
oranges,
strawberries,
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C. Causes
1. Isotonic overhydration
a. Inadequately controlled IV therapy
b . Kidney disease
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 kidney disease
b . Heart failure
c. Syndrom e of inappropriate antidiuretic horm one secretion
d . Inadequately controlled IV therapy
e. Replacem ent of isotonic fluid loss with hypoton ic fluids
f. Irrigation of wounds and body cavities with
hypotonic fluids
D. Assessm ent (see Table 8-1)
E. Interventions
1. Monitor cardiovascular, respiratory, neurom uscular, renal, integum entary, and gastrointestinal
status.
2. Preven t further fluid overload and restore norm al fluid balance.
3. Adm in ister diuretics; osm otic diuretics m ay be
prescribed initially to preven t severe electrolyte
im balances.
4. Restrict fluid and sodium intake as prescribed.
5. Monitor intake and output; m onitor weight.
6. Monitor electrolyte values, and prepare to administer medication to treat an imbalance if present.
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1. Mon itor cardiovascular, respiratory, neurom uscular, renal, integum entary, and gastrointestinal
status.
2. Prevent further fluid losses and increase fluid
com partm ent volum es to norm al ranges.
3. Provide oral rehydration therapy if possible and
IV fluid replacem ent if the deh ydration is severe;
m on itor intake and output.
4. In general, isotonic deh ydration is treated with
isoton ic fluid solution s, hypertonic dehydration
with hypotonic fluid solutions, and hypoton ic
dehydration with hypertonic fluid solutions.
5. Adm in ister m edication s, such as antidiarrheal,
antim icrobial, antiem etic, and antipyretic m edication s, as prescribed to correct the cause and
treat any sym ptom s.
6. Mon itor electrolyte values and prepare to adm inister m edication to treat an im balance, if present.
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UNIT III Nursing Sciences
B. Causes
1. Actual total body potassium loss
a. Excessive use of m edications such as diuretics
or corticosteroids
b . Increased secretion of aldosterone, such as in
Cushing’s syndrom e
c. Vom iting, diarrhea
d . Woun d drainage, particularly gastrointestinal
e. Prolonged nasogastric suction
f. Excessive diaphoresis
g. Kidney disease im pairing reabsorption of
potassium
2. Inadequate potassium intake: Fasting; nothin g
by m outh status
3. Movem ent of potassium from the extracellular
fluid to the intracellular fluid
a. Alkalosis
b . Hyperinsulin ism
4. Dilution of serum potassium
a. Water intoxication
b . IVtherapy with potassium -deficient solutions
C. Assessm ent (Tables 8-2 and 8-3)
D. Interventions
1. Monitor cardiovascular, respiratory, neurom uscular, gastrointestinal, and renal status, and place
the client on a cardiac m onitor.
2. Monitor electrolyte values.
3. Adm in ister potassium supplem ents orally or
intravenously, as prescribed.
4. Oral potassium supplem ents
a. Oral potassium supplem ents m ay cause nausea
and vomiting and they should not be taken on
an empty stomach; if the client complains of
abdom inal pain, distention, nausea, vomiting,
diarrhea, or gastrointestinal bleeding, the supplement m ay need to be discontinued.
b . Liquid potassium chloride has an unpleasant
taste and should be taken with juice or
another liquid.
5. Intraven ously adm inistered potassium (Box 8-3)
6. Institute safety m easures for the clien t experiencing m uscle weakness.
7. If the client is taking a potassium -losin g diuretic,
it m ay be discontinued; a potassium -retainin g
diuretic m ay be prescribed.
8. Instruct the client about foods that are high in
potassium conten t (see Box 8-2).
Potassium is never administered by IV push, intramuscular, or subcutaneous routes. IV potassium is
always diluted and administered using an infusion
device!
V. Hyperkalemia
A. Description
1. Hyperkalem ia is a serum potassium level that
exceeds 5.0 m Eq/L (5.0 m m ol/L) (see Box 8-2).
TABLE 8-2 Assessment Findings: Hypokalemia
and Hyperkalemia
Hypokalemia
Hyperkalemia
Cardiovascular
▪ Thready, weak, irregular pulse ▪ Slow, weak, irregular heart rate
▪ Weak peripheral pulses
▪ Decreased blood pressure
▪ Orthostatic hypotension
Respiratory
▪ Shallow, ineffective
▪
respirations that result from
profound weakness of the
skeletal muscles of respiration
Diminished breath sounds
Neuromuscular
▪ Anxiety, lethargy, confusion,
coma
▪ Profound weakness of the
skeletal muscles leading to
respiratory failure
▪ Early: Muscle twitches,
▪ Skeletal muscle weakness, leg ▪
cramps
▪ Loss of tactile discrimination
▪ Paresthesias
▪ Deep tendon hyporeflexia
cramps, paresthesias (tingling
and burning followed by
numbness in the hands and
feet and around the mouth)
Late: Profound weakness,
ascending flaccid paralysis in
the arms and legs (trunk,
head, and respiratory muscles
become affected when the
serum potassium level
reaches a lethal level)
Gastrointestinal
▪ Decreased motility, hypoactive ▪ Increased motility,
to absent bowel sounds
hyperactive bowel sounds
▪ Nausea, vomiting,
▪ Diarrhea
▪
constipation, abdominal
distention
Paralytic ileus
Laboratory Findings
▪ Serum potassium level lower
▪ Serum potassium level that
▪ Electrocardiogram changes:
▪
than 3.5 mEq/ L (3.5 mmol/ L)
ST depression; shallow, flat,
or inverted T wave; and
prominent U wave
exceeds 5.0 mEq/ L
(5.0 mmol/ L)
Electrocardiographic changes:
Tall peaked T waves, flat P
waves, widened QRS
complexes, and prolonged PR
intervals
2. Pseudohyperkalem ia: a condition that can occur
due to m ethods of blood specim en collection and
cell lysis; if an increased serum value is obtained
in the absence of clin ical sym ptom s, the specim en should be redrawn and evaluated.
B. Causes
1. Excessive potassium intake
a. Overingestion of potassium -con taining foods
or m edications, such as potassium chloride or
salt substitutes
b . Rapid infusion of potassium -con taining IV
solution s
2. Decreased potassium excretion
Tall peaked T waves
Flat P waves
Widened QRS complexes
Prolonged PR interval
Hypomagnesemia
Tall T waves
Depressed ST segment
Hypermagnesemia
Prolonged PR interval
Widened QRS complexes
a. Potassium -retainin g diuretics
b . Kidney disease
c. Adrenal insufficiency, such as in Addison’s
disease
3. Movem ent of potassium from the intracellular
fluid to the extracellular fluid
a. Tissue dam age
b . Acidosis
c. Hyperuricem ia
d . Hypercatabolism
C. Assessm ent (see Tables 8-2 and 8-3)
Monitor the client closely for signs of a potassium
imbalance. A potassium imbalance can cause cardiac
dysrhythmias that can be life-threatening!
BOX 8-3
▪
▪
▪
▪
▪
Monitor the serum potassium level closely when a
client is receiving a potassium-retaining diuretic!
VI. Hyponatremia
A. Description
1. Hyponatrem ia is a serum sodium level lower
than 135 m Eq/L (135 m m ol/L) (Box 8-4).
Precautions with Intravenously Administered Potassium
Potassium is never given by intravenous (IV) push or by the
intramuscular or subcutaneous route.
A dilution of no more than 1 mEq/ 10 mL (1 mmol/ 10 mL) of
solution is recommended.
Manyhealth care agencies supplyprepared IVsolutions containing potassium; before administering and frequently during infusion of the IV solution, rotate and invert the bag to
ensure that the potassium is distributed evenly throughout
the IV solution.
Ensure that the IV bag containing potassium is properly
labeled.
The maximum recommended infusion rate is 5 to 10 mEq/
hour (5 to 10 mmol/ hour), never to exceed 20 mEq/ hour
(20 mmol/ hour) under any circumstances.
▪
▪
▪
A client receiving more than 10 mEq/ hour (10 mmol/ hour)
should be placed on a cardiac monitor and monitored for
cardiac changes, and the infusion should be controlled by
an infusion device.
Potassium infusion can cause phlebitis; therefore, the nurse
should assess the IV site frequently for signs of phlebitis or
infiltration. If either occurs, the infusion should be stopped
immediately.
The nurse should assess renal function before administering
potassium, and monitor intake and output during
administration.
s
Hyperkalemia
l
ST depression
Shallow, flat, or inverted T wave
Prominent U wave
a
Hypokalemia
t
Shortened ST segment
Widened T wave
n
Hypercalcemia
e
Prolonged ST segment
Prolonged QT interval
m
Hypocalcemia
a
Electrocardiographic Changes
d
Electrolyte Imbalance
n
Imbalances
D. Interventions
1. Monitor cardiovascular, respiratory, neurom uscular, renal, and gastrointestinal status; place
the client on a cardiac m onitor.
2. Discontinue IVpotassium (keep the IVcatheter patent), and withhold oral potassium supplements.
3. Initiate a potassium -restricted diet.
4. Prepare to adm inister potassium -excretin g
diuretics if renal function is not im paired.
5. If renal function is impaired, prepare to administer
sodium polystyrene sulfonate (oral or rectal route),
a cation-exchange resin that promotes gastrointestinal sodium absorption and potassium excretion.
6. Prepare the client for dialysis if potassium levels
are critically high.
7. Prepare for the adm inistration of IV calcium if
hyperkalem ia is severe, to avert m yocardial
excitability.
8. Prepare for the IV adm inistration of hypertonic
glucose with regular insulin to m ove excess
potassium into the cells.
9. When blood transfusions are prescribed for a client with a potassium im balance, the client
should receive fresh blood, if possible; transfusions of stored blood m ay elevate the potassium
level because the breakdown of older blood cells
releases potassium .
10. Teach the clien t to avoid foods high in potassium
(see Box 8-2).
11. Instruct the client to avoid the use of salt substitutes or oth er potassium -containing substances.
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TABLE 8-3 Electrocardiographic Changes in Electrolyte
85
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CHAPTER 8 Fluids and Electrolytes
CHAPTER 8 Fluids and Electrolytes
87
TABLE 8-4 Assessment Findings: Hyponatremia and Hypernatremia
s
Hypernatremia
elevated central venous pressure
Respiratory
▪ Shallow, ineffective respiratory movement is a late manifestation related to skeletal ▪ Pulmonary edema if hypervolemia is present
muscle weakness
Neuromuscular
▪ Generalized skeletal muscle weakness that is worse in the extremities
▪ Diminished deep tendon reflexes
Central Nervous System
▪ Headache
▪ Personality changes
▪ Confusion
▪ Seizures
▪ Coma
Gastrointestinal
▪ Increased motility and hyperactive bowel sounds
▪ Nausea
▪ Abdominal cramping and diarrhea
Renal
▪ Increased urinary output
Integumentary
▪ Dry mucous membranes
▪ Early: Spontaneous muscle twitches; irregular muscle
contractions
▪ Late: Skeletal muscle weakness; deep tendon reflexes
diminished or absent
▪ Altered cerebral function is the most common
manifestation of hypernatremia
▪ Normovolemia or hypovolemia: Agitation, confusion,
seizures
▪ Hypervolemia: Lethargy, stupor, coma
▪ Extreme thirst
▪ Decreased urinary output
▪ Dry and flushed skin
▪ Dry and sticky tongue and mucous membranes
▪ Presence or absence of edema, depending on fluid
volume changes
Laboratory Findings
▪ Serum sodium level less than 135 mEq/ L (135 mmol/ L)
▪ Decreased urinary specific gravity
BOX 8-5
Calcium
Normal Value
9.0 to 10.5 mg/ dL (2.25 to 2.75 mmol/ L)
Common Food Sources
Cheese
Collard greens
Kale
Milk and soy milk
Rhubarb
Sardines
Tofu
Yogurt
▪ Serum sodium level that exceeds 145 mEq/ L(145 mmol/ L)
▪ Increased urinary specific gravity
3. Conditions that decrease the ionized fraction of
calcium
a. Hyperprotein em ia
b . Alkalosis
c. Medications such as calcium chelators or
binders
d . Acute pancreatitis
e. Hyperphosphatem ia
f. Im m obility
g. Rem oval or destruction of the parathyroid
glands
C. Assessm ent (Table 8-5 and Fig. 8-3; also see
Table 8-3)
D. Interventions
t
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m
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▪ Symptoms vary with changes in vascular volume
▪ Heart rate and blood pressure respond to vascular
volume status
▪ Normovolemic: Rapid pulse rate, normal blood pressure
▪ Hypovolemic: Thready, weak, rapid pulse rate; hypotension; flat neck veins; normal or
low central venous pressure
▪ Hypervolemic: Rapid, bounding pulse; blood pressure normal or elevated; normal or
a
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Cardiovascular
F
Hyponatremia
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UNIT III Nursing Sciences
TABLE 8-5 Assessment Findings: Hypocalcemia and Hypercalcemia
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Hypocalcemia
Hypercalcemia
Cardiovascular
▪ Decreased heart rate
▪ Hypotension
▪ Diminished peripheral pulses
▪ Increased heart rate in the early phase; bradycardia that
can lead to cardiac arrest in late phases
▪ Increased blood pressure
▪ Bounding, full peripheral pulses
Respiratory
▪ Not directly affected; however, respiratory failure or arrest can result from decreased ▪ Ineffective respiratory movement as a result of profound
respiratory movement because of muscle tetany or seizures
skeletal muscle weakness
Neuromuscular
▪ Irritable skeletal muscles: Twitches, cramps, tetany, seizures
▪ Painful muscle spasms in the calf or foot during periods of inactivity
▪ Paresthesias followed by numbness that may affect the lips, nose, and ears in
addition to the limbs
▪ Positive Trousseau’s and Chvostek’s signs
▪ Hyperactive deep tendon reflexes
▪ Anxiety, irritability
▪ Profound muscle weakness
▪ Diminished or absent deep tendon reflexes
▪ Disorientation, lethargy, coma
Renal
▪ Urinary output varies depending on the cause
▪ Urinary output varies depending on the cause
Gastrointestinal
▪ Increased gastric motility; hyperactive bowel sounds
▪ Cramping, diarrhea
▪ Decreased motility and hypoactive bowel sounds
▪ Anorexia, nausea, abdominal distention, constipation
Laboratory Findings
▪ Serum calcium level less than 9.0 mg/ dL (2.25 mmol/ L)
▪ Electrocardiographic changes: Prolonged ST interval, prolonged QT interval
A
B
▪ Serum calcium level that exceeds 10.5 mg/ dL
(2.75 mmol/ L)
▪ Electrocardiographic changes: Shortened ST segment,
widened T wave
C
FIGURE 8-3 Tests for hypocalcemia. A, Chvostek’s sign is contraction of facial muscles in response to a light tap over the facial nerve in front of the ear. B,
Trousseau’s sign is a carpal spasm induced by inflating a blood pressure cuff (C) above the systolic pressure for a few minutes.
1. Monitor cardiovascular, respiratory, neurom uscular, and gastrointestinal status; place the client
on a cardiac m onitor.
2. Adm in ister calcium supplem ents orally or calcium intravenously.
3. When administering calcium intravenously, warm
the injection solution to body tem perature before
adm inistration and adm inister slowly; m onitor for
electrocardiographic changes, observe for infiltration, and m onitor for hypercalcemia.
4. Adm in ister m edications that increase calcium
absorption.
5.
6.
7.
8.
a. Alum in um hydroxide reduces phosphorus
levels, causing the countereffect of increasing
calcium levels.
b . Vitam in D aids in the absorption of calcium
from the intestinal tract.
Provide a quiet environm ent to reduce en vironm ental stim uli.
Initiate seizure precautions.
Move the client carefully, and m onitor for signs
of a pathological fracture.
Keep 10% calcium gluconate available for treatm ent of acute calcium deficit.
CHAPTER 8 Fluids and Electrolytes
A client with a calcium imbalance is at risk for a
pathological fracture. Move the client carefully and
slowly; assist the client with ambulation.
X. Hypomagnesemia
A. Description: Hypom agnesem ia is a serum magnesium
level lower than 1.3 m Eq/L (0.65 m mol/L) (Box 8-6).
Magnesium
B. Causes
1. Insufficient m agnesium intake
a. Malnutrition and starvation
b . Vom iting or diarrhea
c. Malabsorption syndrom e
d . Celiac disease
e. Crohn’s disease
2. Increased m agnesium excretion
a. Medications such as diuretics
b . Chronic alcoholism
3. Intracellular m ovem ent of m agnesium
a. Hyperglycem ia
b . Insulin adm inistration
c. Sepsis
C. Assessm ent (Table 8-6; also see Table 8-3)
D. Interventions
1. Monitor cardiovascular, respiratory, gastrointestinal, neurom uscular, and central nervous system status; place the client on a cardiac m onitor.
2. Because hypocalcem ia frequently accom panies
hypom agnesem ia, interven tions also aim to
restore norm al serum calcium levels.
3. Oral preparations of m agnesium m ay cause diarrhea and increase m agnesium loss.
4. Magnesium sulfate by the IV route may be prescribed in ill clients when the magnesium level is
low (intramuscular injections cause pain and tissue damage); initiate seizure precautions, monitor
serum magnesium levels frequently, and monitor
for diminished deep tendon reflexes, suggesting
hypermagnesemia, during the administration of
magnesium.
5. Instruct the client to increase the intake of foods
that contain m agnesium (see Box 8-6).
XI. Hypermagnesemia
A. Description: Hyperm agnesem ia is a serum magnesium level that exceeds 2.1 m Eq/L (1.05 m m ol/L)
(see Box 8-6).
l
a
e
m
a
d
Avocado
Canned white tuna
Cauliflower
Green leafy vegetables, such as spinach and broccoli
Milk
Oatmeal, wheat bran
Peanut butter, almonds
Peas
Pork, beef, chicken, soybeans
Potatoes
Raisins
Yogurt
n
Common Food Sources
n
t
1.3 to 2.1 mEq/ L (0.65 to 1.05 mmol/ L)
s
Normal Value
u
IX. Hypercalcemia
A. Description: Hypercalcemia is a serum calcium level
that exceeds 10.5 mg/dL(2.75 mm ol/L) (see Box 8-5).
B. Causes
1. In creased calcium absorption
a. Excessive oral intake of calcium
b . Excessive oral intake of vitam in D
2. Decreased calcium excretion
a. Kidney disease
b . Use of thiazide diuretics
3. In creased bon e resorption of calcium
a. Hyperparath yroidism
b . Hyperthyroidism
c. Malignancy (bone destruction from m etastatic tum ors)
d . Im m obility
e. Use of glucocorticoids
4. Hem oconcentration
a. Dehydration
b . Use of lithium
c. Adrenal insufficiency
C. Assessm ent (see Tables 8-3 and 8-5)
D. Interventions
1. Mon itor cardiovascular, respiratory, neurom uscular, renal, and gastrointestinal status; place
the client on a cardiac m onitor.
2. Discon tinue IV infusions of solutions containing
calcium and oral m edication s containing calcium or vitam in D.
3. Thiazide diuretics m ay be discontinued and
replaced with diuretics that enhance the excretion of calcium .
4. Adm in ister m edication s as prescribed that
inh ibit calcium resorption from the bone, such
as phosph orus, calcitonin, bisphosphonates,
and prostaglandin synthesis inh ibitors (acetylsalicylic acid, nonsteroidal antiinflam m atory
m edications).
5. Prepare the clien t with severe hypercalcem ia for
dialysis if m edications fail to reduce the serum
calcium level.
6. Move the client carefully and m on itor for signs of
a pathological fracture.
7. Monitor for flank or abdominal pain, and strain the
urine to check for the presence of urinary stones.
8. In struct the client to avoid foods high in calcium
(see Box 8-5).
BOX 8-6
F
9. In struct the client to consum e foods high in calcium (see Box 8-5).
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TABLE 8-6 Assessment Findings: Hypomagnesemia
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and Hypermagnesemia
Hypomagnesemia
Cardiovascular
▪ Tachycardia
▪ Hypertension
Respiratory
▪ Shallow respirations
Neuromuscular
▪ Twitches, paresthesias
▪ Positive Trousseau’s and
Chvostek’s signs
▪ Hyperreflexia
▪ Tetany, seizures
Central Nervous System
▪ Irritability
▪ Confusion
Laboratory Findings
Hypermagnesemia
▪ Bradycardia, dysrhythmias
▪ Hypotension
▪ Respiratory insufficiency
when the skeletal muscles of
respiration are involved
▪ Diminished or absent deep
tendon reflexes
▪ Skeletal muscle weakness
▪ Drowsiness and lethargy that
progresses to coma
▪ Serum magnesium level
▪ Serum magnesium level that
▪
▪
less than 1.3 mEq/ L
(0.65 mmol/ L)
Electrocardiographic changes:
Tall T waves, depressed ST
segments
exceeds 2.1 mEq/ L
(1.05 mmol/ L)
Electrocardiographic changes:
Prolonged PR interval,
widened QRS complexes
B. Causes
1. Increased m agnesium intake
a. Magnesium -containin g antacids and laxatives
b . Excessive adm inistration of m agnesium
intravenously
2. Decreased renal excretion of m agnesium as a
result of renal insufficiency
C. Assessm ent (see Tables 8-3 and 8-6)
D. Interventions
1. Monitor cardiovascular, respiratory, neurom uscular, and central nervous system status; place
the client on a cardiac m onitor.
2. Diuretics are prescribed to increase renal excretion of m agnesium .
3. In traven ously adm in istered calcium ch loride
or calcium glucon ate m ay be prescribed to
reverse th e effects of m agn esium on cardiac
m uscle.
4. Instruct the client to restrict dietary intake of
m agnesium -containin g foods (see Box 8-6).
5. Instruct the clien t to avoid the use of laxatives
and antacids containing m agnesium .
Calcium gluconate is the antidote for magnesium
overdose.
BOX 8-7
Phosphorus (Phosphate)
Normal Value
3.0 to 4.5 mg/ dL (0.97 to 1.45 mmol/ L)
Common Food Sources
Dairy products
Fish
Nuts
Pork, beef, chicken, organ meats
Pumpkin, squash
Whole-grain breads and cereals
XII. Hypophosphatemia
A. Description
1. Hypoph osphatem ia is a serum phosphorus
(phosphate) level lower than 3.0 m g/dL
(0.97 m m ol/L) (Box 8-7).
2. A decrease in the serum phosphorus level is
accom panied by an increase in the serum
calcium level.
B. Causes
1. Insufficient phosphorus intake: Malnutrition and
starvation
2. Increased phosph orus excretion
a. Hyperparathyroidism
b . Malign ancy
c. Use of magnesium-based or alum inum
hydroxide–based antacids
3. Intracellular shift
a. Hyperglycem ia
b . Respiratory alkalosis
C. Assessm ent
1. Cardiovascular
a. Decreased contractility and cardiac output
b . Slowed peripheral pulses
2. Respiratory: Shallow respirations
3. Neurom uscular
a. Weakn ess
b . Decreased deep tendon reflexes
c. Decreased bon e density that can cause fractures and alterations in bone shape
d . Rhabdom yolysis
4. Central nervous system
a. Irritability
b . Confusion
c. Seizures
5. Hem atological
a. Decreased platelet aggregation and increased
bleeding
b . Im m un osuppression
D. Interven tions
1. Monitor cardiovascular, respiratory, neurom uscular, central nervous system , and hem atological
status.
A decrease in the serum phosphorus level is accompanied by an increase in the serum calcium level, and an
increase in the serum phosphorus level is accompanied
by a decrease in the serum calcium level. This is called a
reciprocal relationship.
XIII. Hyperphosphatemia
A. Description
1. Hyperphosph atem ia is a serum phosphorus level
that exceeds 4.5 m g/dL (1.45 m m ol/L) (see
Box 8-7).
2. Most body system s tolerate elevated serum phosphorus levels well.
3. An increase in the serum phosphorus level is
accom pan ied by a decrease in the serum
calcium level.
4. The problem s that occur in hyperphosph atem ia
cen ter on the hypocalcem ia that results when
serum phosphorus levels increase.
B. Causes
1. Decreased renal excretion resultin g from renal
insufficiency
2. Tum or lysis syndrom e
3. In creased intake of phosph orus, includin g dietary intake or overuse of phosphate-con taining
laxatives or enem as
4. Hypoparathyroidism
C. Assessm ent: Refer to assessm ent of hypocalcem ia.
D. Interventions
1. In terventions en tail the m anagem ent of
hypocalcem ia.
2. Adm inister phosphate-binding m edications that
increase fecal excretion of phosphorus by binding
phosphorus from food in the gastrointestinal tract.
3. Instruct the client to avoid phosphate-containingm edications, including laxatives and enemas.
4. In struct the client to decrease the intake of food
that is high in phosph orus (see Box 8-7).
Reference: Lewis et al. (2014), pp. 297–298.
P R AC T I C E Q U E S T I O N S
36. The nurse is caring for a client with heart failure. On
assessm ent, the nurse notes that the client is dyspneic, and crackles are audible on auscultation. What
additional m anifestations would the nurse expect to
note in this client if excess fluid volume is present?
1. Weight loss and dry skin
2. Flat neck and hand veins and decreased urinary
output
3. An increase in blood pressure and increased
respirations
4. Weakness and decreased central venous
pressure (CVP)
37. The nurse is preparing to care for a client with a
potassium deficit. The nurse reviews the client’s
record and determ ines that the client is at risk for
developing the potassium deficit because of which
situation?
1. Sustained tissue dam age
2. Requires nasogastric suction
3. Has a history of Addison’s disease
4. Uric acid level of 9.4 m g/dL (559 µm ol/L)
38. The nurse reviews a client’s electrolyte laboratory
report and notes that the potassium level is
2.5 mEq/L (2.5 mmol/L). Which patterns should the
nurse watch for on the electrocardiogram (ECG) as a
result of the laboratory value? Select all that apply.
1. U waves
2. Absent P waves
3. Inverted T waves
4. Depressed ST segm ent
5. Widened QRS com plex
s
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Answer: Cardiac changes in hypokalemia include impaired
repolarization, resulting in a flattening of the T wave and
eventually the emergence of a U wave. Therefore, the nurse
should suspect hypokalemia. The incidence of potentially
lethal ventricular dysrhythmias is increased in hypokalemia.
The nurse should immediately assess the client’s vital signs
and cardiac status for signs of hypokalemia. The nurse
should also check the client’s most recent serum potassium
level and then contact the health care provider to report
the findings and obtain prescriptions to treat the
hypokalemic state.
u
CRITICAL THINKING What Should You Do?
n
t
5. Instruct the client in m edication adm inistration:
Take phosph ate-binding m edication s, em phasizing that they should be taken with m eals or
im m ediately after m eals.
F
2. Discon tinue m edications that contribute to
hypophosph atem ia.
3. Adm in ister phosphorus orally alon g with a vitam in D supplem ent.
4. Prepare to adm inister phosph orus intravenously
when serum phosphorus levels fall below 1 m g/
dL and when the client experiences critical clinical m anifestations.
5. Adm in ister IV phosph orus slowly because of the
risks associated with hyperphosph atem ia.
6. Assess the renal system before adm inistering
phosphorus.
7. Move the client carefully, and m onitor for signs
of a pathological fracture.
8. Instruct the client to increase the intake of the
phosphorus-containing foods while decreasing
the intake of any calcium -containing foods (see
Boxes 8-5 and 8-7).
91
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CHAPTER 8 Fluids and Electrolytes
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UNIT III Nursing Sciences
39. Potassium chloride intravenously is prescribed for a
client with hypokalem ia. Which action s should the
nurse take to plan for preparation and adm inistration of the potassium ? Select all th at apply.
1. Obtain an intravenous (IV) infusion pum p.
2. Monitor urine output during administration.
3. Prepare
the
m edication
for
bolus
adm inistration.
4. Monitor the IV site for signs of infiltration or
phlebitis.
5. Ensure that the m edication is diluted in the
appropriate volum e of fluid.
6. Ensure that the bag is labeled so that it reads
the volum e of potassium in the solution .
40. The nurse provides instructions to a client with a low
potassium level about the foods that are high in
potassium and tells the client to consum e which
foods? Select all th at apply.
1. Peas
2. Raisin s
3. Potatoes
4. Cantaloupe
5. Cauliflower
6. Strawberries
41. Th e n urse is reviewin g laboratory results an d n otes
th at a clien t’s serum sodium level is 150 m Eq/ L
(150 m m ol/ L). Th e n urse reports th e serum
sodium level to th e h ealth care provider (HCP)
an d th e HCP prescribes dietary in struction s based
on th e sodium level. Wh ich acceptable food item s
does th e n urse in struct th e clien t to con sum e?
Select all th at ap p ly.
1. Peas
2. Nuts
3. Cheese
4. Cauliflower
5. Processed oat cereals
42. The nurse is assessing a client with a suspected diagnosis of hypocalcemia. Which clinical m anifestation
would the nurse expect to note in the client?
1. Twitch ing
2. Hypoactive bowel soun ds
3. Negative Trousseau’s sign
4. Hypoactive deep tendon reflexes
43. The nurse is caring for a client with hypocalcem ia.
Which patterns would the nurse watch for on the
electrocardiogram as a result of the laboratory
value? Select all th at app ly.
1. U waves
2. Widened T wave
3. Prom inent U wave
4. Prolon ged QT interval
5. Prolon ged ST segm ent
44. The nurse reviews the electrolyte results of an
assigned client and notes that the potassium level
is 5.7 m Eq/L (5.7 m m ol/L). Which pattern s would
the nurse watch for on the cardiac m onitor as a
result of the laboratory value? Select all th at apply.
1. ST depression
2. Prom in ent U wave
3. Tall peaked T waves
4. Prolonged ST segm ent
5. Widened QRS com plexes
45. Which client is at risk for the developm ent of a
sodium level at 130 m Eq/L (130 m m ol/L)?
1. The client who is taking diuretics
2. The client with hyperaldosteronism
3. The client with Cush ing’s syndrom e
4. The client who is taking corticosteroids
46. The nurse is caring for a client with heart failure who
is receiving high doses of a diuretic. On assessm ent,
the nurse notes that the client has flat neck veins,
generalized m uscle weakness, and dim inish ed deep
tendon reflexes. The nurse suspects hyponatrem ia.
What additional signs would the nurse expect to
note in a client with hyponatrem ia?
1. Muscle twitches
2. Decreased urinary output
3. Hyperactive bowel soun ds
4. Increased specific gravity of the urine
47. The nurse reviews a client’s laboratory report and
notes that the clien t’s serum phosphorus (phosphate) level is 1.8 m g/dL (0.45 m m ol/L). Which
condition m ost likely caused this serum phosphorus level?
1. Malnutrition
2. Ren al insufficiency
3. Hypoparathyroidism
4. Tum or lysis syndrom e
48. The nurse is reading a health care provider’s (HCP’s)
progress notes in the client’s record and reads that
the HCP has docum en ted “insensible fluid loss of
approxim ately 800 m L daily.” The nurse m akes a
notation that insensible fluid loss occurs through
which type of excretion?
1. Urinary output
2. Wound drainage
3. Integum en tary output
4. The gastrointestinal tract
49. The nurse is assigned to care for a group of clients.
On review of the clients’ m edical records, the nurse
determ ines that which client is m o st likely at risk for
a fluid volum e deficit?
1. A client with an ileostom y
2. A client with heart failure
51. On review of the clients’ m edical records, the nurse
determ ines that which clien t is at risk for fluid volum e excess?
AN S W E R S
36. 3
Ra tiona le: A fluid volum e excess is also known as overhydration
or fluid overload and occurs when fluid intake or fluid retention
exceeds the fluid needs of the body. Assessm ent findings associated with fluid volum e excess include cough, dyspnea,
crackles, tachypnea, tachycardia, elevated blood pressure,
bounding pulse, elevated CVP, weight gain, edem a, neck and
hand vein distention, altered level of consciousness, and
decreased hem atocrit. Dry skin, flat neck and hand veins,
decreased urinary output, and decreased CVP are noted in fluid
volum e deficit. Weakness can be present in either fluid volum e
excess or deficit.
Test-Ta king Stra tegy: Focus on the su b ject, fluid volum e
excess. Rem em ber that when there is m ore than one part to
an option, all parts need to be correct in order for the option
to be correct. Think about the pathophysiology associated with
a fluid volum e excess to assist in directing you to the correct
option. Also, note that the incorrect options are co m p ar ab le
o r alike in that each includes m anifestations that reflect a
decrease.
Review: The assessm ent findings noted in flu id vo lu m e excess
Level of Cognitive Ability: Synthesizing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Fluid and Electrolytes; Perfusion
References: Ignatavicius, Workm an (2016), pp. 158–159;
Lewis et al. (2014), pp. 292–293.
37. 2
Ra tiona le: The norm al serum potassium level is 3.5 to
5.0 m Eq/L (3.5 to 5.0 m m ol/L). A potassium deficit is known
as hypokalemia. Potassium -rich gastrointestinal fluids are lost
through gastrointestinal suction, placing the client at risk for
hypokalem ia. The client with tissue dam age or Addison’s disease and the client with hyperuricem ia are at risk for hyperkalem ia. The norm al uric acid level for a fem ale is 2.7 to 7.3 m g/dL
(0.16 to 0.43 m m ol/L) and for a m ale is 4.0 to 8.5 m g/ dL (0.24
to 0.51 m m ol/L). Hyperuricem ia is a cause of hyperkalem ia.
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50. The nurse caring for a client who has been receiving
intravenous (IV) diuretics suspects that the client is
experiencing a fluid volum e deficit. Which assessm en t finding would the nurse note in a client with
this condition?
1. Weight loss and poor skin turgor
2. Lung congestion and increased heart rate
3. Decreased hem atocrit and increased urine output
4. Increased respirations and increased blood
pressure
1. The client taking diuretics and has tenting of
the skin
2. The clien t with an ileostom y from a recent
abdom inal surgery
3. The client who requires interm itten t gastrointestinal suction ing
4. The client with kidn ey disease and a 12-year history of diabetes m ellitus
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3. A clien t on long-term corticosteroid therapy
4. A client receiving frequent woun d irrigations
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52. Which client is at risk for the developm ent of a
potassium level of 5.5 m Eq/L (5.5 m m ol/L)?
1. The clien t with colitis
2. The client with Cushing’s syndrom e
3. The client who has been overusin g laxatives
4. The client who has sustain ed a traum atic burn
Test-Ta king Stra tegy: Note that the su b ject of the question is
potassium deficit. First recall the norm al uric acid levels and the
causes of hypokalem ia to assist in elim inating option 4. For the
rem aining options, note that the correct option is the only one
that identifies a loss of body fluid.
Review: The causes of h yp o kalem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), pp. 296, 1211.
38. 1, 3, 4
Ra tiona le: The normal serum potassium level is 3.5 to 5.0 mEq/L
(3.5 to 5.0 mmol/L). Aserum potassium level lower than 3.5 mEq/
L (3.5 mmol/L) indicates hypokalemia. Potassium deficit is an
electrolyte imbalance that can be potentially life-threatening. Electrocardiographicchangesinclude shallow, flat, or inverted Twaves;
STsegment depression;and prominent U waves.Absent Pwavesare
not a characteristicofhypokalemia but maybenoted in a client with
atrial fibrillation, junctional rhythms, or ventricular rhythms. A
widened QRS complex may be noted in hyperkalemia and in
hypermagnesemia.
Test-Ta king Stra tegy: Focus on the su b ject , the ECG patterns
that m ay be noted with a client with a potassium level of
2.5 m Eq/L (2.5 m m ol/ L). From the inform ation in the question, you need to determ ine that the client is experiencing
severe hypokalem ia. From this point, you m ust know the electrocardiographic changes that are expected when severe hypokalem ia exists.
Review: The electrocardiographic changes that occur in
h yp o kalem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
References: Ignatavicius, Workm an (2016), pp. 163–164;
Lewis et al. (2014), p. 298.
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39. 1, 2, 4, 5, 6
Ra tiona le: Potassium chloride adm inistered intravenously
m ust always be diluted in IV fluid and infused via an infusion
pum p. Potassium chloride is never given by bolus (IV push).
Giving potassium chloride by IV push can result in cardiac
arrest. The nurse should ensure that the potassium is diluted
in the appropriate am ount of diluent or fluid. The IV bag containing the potassium chloride should always be labeled with
the volum e of potassium it contains. The IV site is m onitored
closely because potassium chloride is irritating to the veins and
there is risk of phlebitis. In addition, the nurse should m onitor
for infiltration. The nurse m onitors urinary output during
adm inistration and contacts the health care provider if the urinary output is less than 30 m L/hour.
Test-Ta king Stra tegy: Focus on the su b ject, the preparation
and adm inistration of potassium chloride intravenously.
Think about this procedure and the effects of potassium . Note
the word bolus in option 3 to assist in elim inating this option.
Review: The precautions with intravenously adm inistered
p o t assiu m
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Im plem entation
Content Area : Pharm acology—Cardiovascular Medications
Priority Concepts: Clinical Judgm ent; Safety
References: Gahart, Nazareno (2015), pp. 1009–1011; Lewis
et al. (2014), p. 298.
40. 2, 3, 4, 6
Ra tiona le: The norm al potassium level is 3.5 to 5.0 m Eq/ L
(3.5 to 5.0 m m ol/L). Com m on food sources of potassium
include avocado, bananas, cantaloupe, carrots, fish, m ushroom s, oranges, potatoes, pork, beef, veal, raisins, spinach,
strawberries, and tom atoes. Peas and cauliflower are high in
m agnesium .
Test-Ta king Stra tegy: Focus on the su b ject , foods high in
potassium . Read each food item and use knowledge about
nutrition and com ponents of food. Recall that peas and cauliflower are high in m agnesium .
Review: The food item s high in p o tassiu m content
Level of Cognitive Ability: Applying
Client Needs: Physiological Integrity
Integra ted Process: Teaching and Learning
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Client Education; Nutrition
References: Lewis et al. (2014), pp. 296, 1115; Nix (2013),
p. 138.
41. 1, 2, 4
Ra tiona le: The norm al serum sodium level is 135 to 145 m Eq/
L (135 to 145 m m ol/L). A serum sodium level of 150 m Eq/L
(150 m m ol/L) indicates hypernatrem ia. On the basis of this
finding, the nurse would instruct the client to avoid foods high
in sodium . Peas, nuts, and cauliflower are good food sources of
phosphorus and are not high in sodium (unless they are
canned or salted). Peas are also a good source of m agnesium .
Processed foods such as cheese and processed oat cereals are
high in sodium content.
Test-Ta king Stra tegy: Focus on the su b ject , foods acceptable
to be consum ed by a client with a sodium level of 150 m Eq/ L
(150 m m ol/L). First, you m ust determ ine that the client has
hypernatrem ia. Select peas and cauliflower first because these
are vegetables. From the rem aining options, note the word processed in option 5 and recall that cheese is high in sodium .
Rem em ber that processed foods tend to be higher in sodium
content.
Review: Foods high in so d iu m content
Level of Cognitive Ability: Applying
Client Needs: Physiological Integrity
Integra ted Process: Teaching and Learning
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Client Education; Nutrition
References: Lewis et al. (2014), p. 295; Nix (2013), p. 141.
42. 1
Ra tiona le: The norm al serum calcium level is 9 to 10.5 m g/dL
(2.25 to 2.75 m m ol/ L). A serum calcium level lower than
9 m g/ dL (2.25 m m ol/L) indicates hypocalcem ia. Signs of
hypocalcem ia include paresthesias followed by num bness,
hyperactive deep tendon reflexes, and a positive Trousseau’s
or Chvostek’s sign. Additional signs of hypocalcem ia include
increased neurom uscular excitability, m uscle cram ps, twitching, tetany, seizures, irritability, and anxiety. Gastrointestinal
sym ptom s include increased gastric m otility, hyperactive
bowel sounds, abdom inal cram ping, and diarrhea.
Test-Ta king Stra tegy: Note that the three incorrect options are
co m p ar ab le o r alike in that they reflect a hypoactivity. The
option that is different is the correct option.
Review: The m anifestations of h yp o calcem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), pp. 299–300.
43. 4, 5
Ra tiona le: The norm al serum calcium level is 9 to 10.5 m g/dL
(2.25 to 2.75 m m ol/ L). A serum calcium level lower than
9 m g/ dL (2.25 m m ol/L) indicates hypocalcem ia. Electrocardiographic changes that occur in a client with hypocalcem ia
include a prolonged QT interval and prolonged ST segm ent.
A shortened ST segm ent and a widened T wave occur with
hypercalcem ia. ST depression and prom inent U waves occur
with hypokalem ia.
Test-Ta king Stra tegy: Focus on the su b ject, the electrocardiographic patterns that occur in a calcium im balance. It is necessary to know the electrocardiographic changes that occur in
hypocalcem ia. Rem em ber that hypocalcem ia causes a prolonged ST segm ent and prolonged QT interval.
Review: The electrocardiographic changes that occur in
h yp o calcem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), p. 299.
44. 3, 5
Ra tiona le: The norm al potassium level is 3.5 to 5.0 m Eq/L
(3.5 to 5.0 m m ol/L). A serum potassium level greater than
45. 1
Ra tiona le: The norm al serum sodium level is 135 to 145 m Eq/
L (135 to 145 m m ol/L). A serum sodium level of 130 m Eq/L
(130 m m ol/L) indicates hyponatrem ia. Hyponatrem ia can
occur in the client taking diuretics. The client taking corticosteroids and the client with hyperaldosteronism or Cushing’s syndrom e are at risk for hypernatrem ia.
Test-Ta king Stra tegy: Focus on the su b ject , the causes of a
sodium level of 130 m Eq/L (130 m m ol/L). First, determ ine
that the client is experiencing hyponatrem ia. Next, you m ust
know the causes of hyponatrem ia to direct you to the correct
option. Also, recall that when a client takes a diuretic, the client
loses fluid and electrolytes.
Review: The norm al serum sodium level and the causes of
h yp o n atr em ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), pp. 295–296.
46. 3
Ra tiona le: The norm al serum sodium level is 135 to 145 m Eq/L
(135 to 145 m m ol/L). Hyponatrem ia is evidenced by a serum
sodium level lower than 135 m Eq/L (135 m m ol/L). Hyperactive bowel sounds indicate hyponatrem ia. The rem aining
options are signs of hypernatrem ia. In hyponatrem ia, m uscle
weakness, increased urinary output, and decreased specific
gravity of the urine would be noted.
Test-Ta king Stra tegy: Focus on th e d at a in t h e qu est io n
an d th e su b ject of th e question , sign s of h ypon atrem ia. It
is n ecessary to kn ow th e sign s of h ypon atrem ia to an swer
correctly. Also, th in k about th e action an d effects of sodium
on th e body to an swer correctly. Rem em ber th at in creased
bowel m otility an d h yperactive bowel soun ds in dicate
hypon atrem ia.
47. 1
Ra tiona le: The norm al serum phosphorus (phosphate) level
is 3.0 to 4.5 m g/dL (0.97 to 1.45 m m ol/L). The client is
experiencing hypophosphatem ia. Causative factors relate to
m alnutrition or starvation and the use of alum inum hydroxide–based or m agnesium -based antacids. Renal insufficiency,
hypoparathyroidism , and tum or lysis syndrom e are causative
factors of hyperphosphatem ia.
Test-Ta king Stra tegy: Note the str at egic wo r d s, most likely.
Focus on the su b ject , a serum phosphorus level of 1.8 m g/
dL (0.45 m m ol/ L). First, you m ust determ ine that the client
is experiencing hypophosphatem ia. From this point, think
about the effects of phosphorus on the body and recall the
causes of hypophosphatem ia in order to answer correctly.
Review: The causative factors associated with h yp o p h o sp h atem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), p. 301.
48. 3
Ra tiona le: Insensible losses m ay occur without the person’s
awareness. Insensible losses occur daily through the skin and
the lungs. Sensible losses are those of which the person is
aware, such as through urination, wound drainage, and gastrointestinal tract losses.
Test-Ta king Stra tegy: Note that the su b ject of the question is
insensible fluid loss. Note that urination, wound drainage, and
gastrointestinal tract losses are co m p ar ab le o r alike in that
they can be m easured for accurate output. Fluid loss through
the skin cannot be m easured accurately; it can only be
approxim ated.
Review: The difference between sen sib le an d in sen sib le flu id
lo ss
Level of Cognitive Ability: Applying
Client Needs: Physiological Integrity
Integra ted Process: Com m unication and Docum entation
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
References: Lewis et al. (2014), pp. 290, 293; Perry, Potter,
Ostendorf (2014), p. 810.
49. 1
Ra tiona le: A fluid volum e deficit occurs when the fluid intake
is not sufficient to m eet the fluid needs of the body. Causes of a
fluid volum e deficit include vom iting, diarrhea, conditions
that cause increased respirations or increased urinary output,
insufficient intravenous fluid replacem ent, draining fistulas,
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Review: The signs associated with h yp o n atr em ia and
h yp er n at r em ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), p. 295.
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5.0 m Eq/L (5.0 m m ol/L) indicates hyperkalem ia. Electrocardiographic changes associated with hyperkalem ia include flat
P waves, prolonged PR intervals, widened QRS com plexes,
and tall peaked T waves. ST depression and a prom inent U
wave occurs in hypokalem ia. A prolonged ST segm ent occurs
in hypocalcem ia.
Test-Ta king Stra tegy: Focus on the su b ject , the electrocardiographic changes that occur in a potassium im balance. From the
inform ation in the question, you need to determ ine that this
condition is a hyperkalem ic one. From this point, you m ust
know the electrocardiographic changes that are expected when
hyperkalem ia exists. Rem em ber that tall peaked T waves, flat P
waves, widened QRS com plexes, and prolonged PR interval are
associated with hyperkalem ia.
Review: The electrocardiographic changes that occur in
h yp er kalem ia
Level of Cognitive Ability: Analyzing
Client Needs: Physiological Integrity
Integra ted Process: Nursing Process—Assessm ent
Content Area : Fundam entals of Care—Fluids & Electrolytes
Priority Concepts: Clinical Judgm ent; Fluid and Electrolytes
Reference: Lewis et al. (2014), p. 296.
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CHAPTER 8 Fluids and Electrolytes