key points ch 11 F&E iggy

Question 1

Chapter 11: Assessment and Care of Patients with Problems of Fluid and Electrolyte Balance
Key Points

Answer 1

The priority concept in this chapter is FLUID AND ELECTROLYTE BALANCE.
The most important interrelated concept for this chapter is PERFUSION.

Question 2

HOMEOSTASIS

Answer 2

• The body has many control mechanisms, called homeostatic mechanisms, to prevent
fluctuations in fluid and electrolytes.

Question 3

PHYSIOLOGIC INFLUENCES ON FLUID AND ELECTROLYTE BALANCE

Answer 3

HYSIOLOGIC INFLUENCES ON FLUID AND ELECTROLYTE BALANCE
• Body fluids are composed of water and particles dissolved or suspended in water.
• The solvent is the water portion of fluids.
• Solutes are the particles dissolved or suspended in the water.
• When solutes express an overall electrical charge, they are known as electrolytes.
• Body function depends on keeping the correct balance of fluid and electrolytes within
each body fluid space.
• Specific processes control normal FLUID AND ELECTROLYTE BALANCE so the internal
environment remains stable even when the external environment changes.
• These processes are filtration, diffusion, and osmosis.
• They determine how, when, and where fluids and particles move across cell membranes.

Question 4

FLUID BALANCE

Body Fluids

Answer 4

ody Fluids
• A person’s age, gender, and amount of fat affect the amount and distribution of body
fluids.
o An older adult has less total body water than a younger adult.
o An obese person has less total body water than a lean person of the same weight
because fat cells contain almost no water.
o Women of any age have less total body water than men of similar sizes and ages,
related to more body fat.
• Assessment is key in managing imbalances.
o Assess patients who have a sudden change in cognition for fluid and electrolyte
imbalances.
o Assess skin turgor on the forehead or the sternum of older patients.
o Use daily weights to determine fluid gains or losses.
o Ask patients about the use of drugs such as diuretics, laxatives, salt substitutes,
and antihypertensives that may alter fluid and electrolyte status.
o Correctly interpret laboratory electrolyte values.
o Assess any patient with a fluid or electrolyte imbalance for falls risk.
o Cardiovascular changes are good indicators of hydration status because of the
relationship between plasma fluid volume, blood pressure, and PERFUSION.
Key Points
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11-2
o Monitor the cardiac and pulmonary status at least every hour when patients with
dehydration are receiving IV fluid replacement therapy.
o Assess the bowel sounds; heart rate, rhythm, and quality; and muscle strength to
evaluate the patient’s responses to therapy for an electrolyte imbalance.
• Use a gait belt when assisting a patient with muscle weakness to walk or transfer.
• Do not give oral fluids to an unconscious patient.
• Offer or ensure that oral care is performed at least every 4 hours for patients with
dehydration.
• The minimum amount of urine output per day to excrete toxic waste products, called the
obligatory urine output, is 400 to 600 mL.
• Other normal water loss occurs through the skin, the lungs, and the intestinal tract.
• Insensible water loss from skin, lungs, and stool is about 500 to 1000 mL/day. If not
balanced by intake, insensible water loss can lead to severe dehydration and electrolyte
imbalances.

Question 5

obligatory urine output,

Answer 5

The minimum amount of urine output per day to excrete toxic waste products, called the
obligatory urine output, is 400 to 600 mL

Question 6

Insensible water loss

Answer 6

Insensible water loss from skin, lungs, and stool is about 500 to 1000 mL/day. If not
balanced by intake, insensible water loss can lead to severe dehydration and electrolyte
imbalances.

Question 7

Hormonal Regulation of Fluid Balance

Answer 7

• The endocrine system helps to control FLUID AND ELECTROLYTE BALANCE.
• Three hormones that help control these critical balances are aldosterone, antidiuretic
hormone (ADH), and natriuretic peptide (NP).

Question 8

Significance of Fluid Balance

Answer 8

icance of Fluid Balance
• The human body requires a balance of body fluids, electrolytes, and acids and bases for
best function.
• The most important fluids to keep in balance are the blood volume (plasma volume) and
the fluid inside the cells (intracellular fluid [ICF]).
• The most critical fluid balance to prevent death is maintaining blood volume at a
sufficient level for blood pressure to remain high enough to ensure adequate PERFUSION
and oxygenation of all organs and tissues.
• Balance of both water and electrolytes is needed for this very vital function.
• Once the kidneys sense that PERFUSION is at risk, renin is secreted into the blood. Renin
then activates angiotensinogen.
• Activated angiotensinogen is angiotensin I, which is relatively weak. It is then acted on
by another enzyme known as angiotensin-converting enzyme (ACE), which converts
angiotensin I into its most active form, angiotensin II.
• Angiotensin II starts several different activities that all work to increase blood volume
and blood pressure.
• Used to treat hypertension, the “ACE inhibitors” are drugs that disrupt the renin–
angiotensin II pathway by reducing the amount of ACE made so that less angiotensin II is
present.
• With less angiotensin II, there is less vasoconstriction and reduced peripheral resistance,
less aldosterone production, and greater excretion of water and sodium in the urine. All of
these responses lead to decreased blood volume and blood pressure.

Question 9

FLUID IMBALANCES

Dehydration

Answer 9

• All patients are at risk for some degree of fluid imbalance because many health problems
can disrupt fluid intake or output.
• In dehydration, fluid intake is less than what is needed to meet the body’s fluid needs,
resulting in a fluid volume deficit.
• Management of dehydration aims to prevent injury, prevent further fluid losses, and
increase fluid compartment volumes to normal ranges.
• Main strategies include assuring patient safety, fluid replacement, and drug therapy.
• Ensure access to adequate fluids for patients who are unable to talk or who have limited
mobility.
• Older adults are at high risk for dehydration because they have less total body water than
younger adults. They also may take drugs such as diuretics, antihypertensives, and
laxatives that increase fluid excretion. For this reason, always assess the FLUID AND
ELECTROLYTE BALANCE status of all older adults.

Question 10

Fluid Overload

Answer 10

d Overload
• Fluid overload, also called overhydration, is an excess of body fluid.
• Fluid overload may be either an actual excess of total body fluid or a relative fluid
excess.
• Careful assessment of fluid overload and development of pulmonary edema is essential to
prevent potential for death.
• The patient with fluid volume overload and edema is at risk for skin breakdown.
• Interventions for patients with fluid overload ensure patient safety, restore normal fluid
balance, provide supportive care until the imbalance is resolved, and prevent future fluid
overload.
Use a pump or controller to deliver intravenous fluids to patients with fluid overload.

Question 11

ELECTROLYTE BALANCE AND IMBALANCES

Answer 11

• Electrolyte imbalances can occur in healthy people as a result of changes in fluid intake
and output, which are usually mild and easily corrected.
• Severe electrolyte imbalances are life threatening.
• Electrolyte homeostasis balances the dietary intake of electrolytes with the renal
excretion or reabsorption of electrolytes.

Question 12

Sodium

Answer 12

• The extracellular fluid (ECF) sodium (Na+
) level determines whether water is retained,
excreted, or moved from one fluid space to another.
• Serum sodium balance is regulated by the kidney under the influences of aldosterone,
ADH, and NP.

Question 13

Hyponatremia

Answer 13

• Hyponatremia is a serum sodium level below 136 mEq/L.
o Sodium imbalances often occur with fluid volume imbalances because the same
hormones regulate both sodium and water balance.
o Cerebral changes are the most obvious problems of hyponatremia. Behavioral
changes result from cerebral edema and increased intracranial pressure.
o Noticing the cause determines to plan appropriate management including drug
therapy, nutrition therapy, preventing fluid overload or a too-rapid change in
serum sodium level.
o Priorities include monitoring patient’s response to therapy, preventing
hypernatremia, and fluid overload.

Question 14

Hypernatremia

Answer 14

• Hypernatremia is a serum sodium level over 145 mEq/L.
o When serum sodium levels are high, severe cellular dehydration with cellular
shrinkage occurs.
o Notice nervous system changes starting with altered cerebral function, assessing
attention span and cognitive function.
o Skeletal muscle changes can begin with muscle twitching.
o Drug and nutrition therapies decrease high serum sodium levels.
o Interventions include ensuring patient safety, skin protection, monitoring
response, and patient and family teaching similar to those for fluid overload.
o Interventions used when sodium levels become life threatening include
hemodialysis and blood ultrafiltration.

Question 15

Potassium

Answer 15

• Keeping the large difference in potassium (K+
) concentration between the ICF and the
ECF is critical for excitable tissues to depolarize and generate action potentials.
• Other functions of potassium include regulating protein synthesis and regulating glucose
use and storage.

Question 16

Hypokalemia

Answer 16

• Hypokalemia is a serum potassium level below 3.5 mEq/L, which can be life threatening
because every body system is affected.
o Drug and nutrition therapies help restore normal serum potassium levels.
o The priorities for nursing care of the patient with hypokalemia are ensuring
adequate gas exchange, patient safety for falls prevention, prevention of injury
from potassium administration, and monitoring the patient’s response to therapy.
o Assess the respiratory status of all patients with hypokalemia.
o Follow facility policy for cardiac monitoring in the presence of hypokalemia.
o Before infusing any IV solution containing potassium chloride, check and recheck the dilution of the drug in the IV solution container.
o Do not give intravenous potassium at a rate greater than 20 mEq/h.
o Never give potassium supplements by the intramuscular, subcutaneous, or IV
push routes.
o Use a pump or controller when giving intravenous potassium-containing
solutions.
o Because potassium is a severe irritant to the vein, assess the IV site hourly, and
ask the patient whether he or she feels burning or pain at the site.
o Immediately stop the infusion of potassium-containing solutions if infiltration or
phlebitis is suspected.
o Oral potassium preparations have a strong, unpleasant taste and can cause nausea
and vomiting. Give the drug during or after a meal and advise patients to not take
it on an empty stomach at home.

Question 17

Hyperkalemia

Answer 17

Hyperkalemia is a serum potassium level greater than 5.0 mEq/L.
o Even slight increases above normal values can affect excitable tissues, especially
Key Points
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11-5
the heart.
o The priorities are assessing for cardiac complications (most common cause of
death), patient safety for falls prevention, monitoring the patient’s response to
therapy, and health teaching.
o Assess all patients with hyperkalemia for cardiac dysrhythmias and
electrocardiographic abnormalities, especially tall T waves, conduction delays,
ventricular fibrillation, and heart block.
o Patients at greatest risk include those with renal dysfunction; chronically ill,
debilitated patients; and older adults.
o The nurse’s response to hyperkalemia is to focus on reducing the serum potassium
level, preventing recurrences, and ensuring patient safety.