Unit 4 - Fluid and Electrolytes

Question 1

What is the definition of fluid and electrolytes?

Answer 1

The process of regulating the extracellular fluid volume, body fluid osmolality, and plasma concentration of electrolytes.

Question 2

What is fluid?

Answer 2

Water plus the substances dissolved and suspended in it. Important characteristics of fluid are its volume (amount) and its degree of concentration (osmolality).

Question 3

What are electrolytes?

Answer 3

Substances that are charged particles (ions) when they are placed in water. Examples include:
* Sodium ions (Na+)
* Potassium ions (K+)
* Calcium ions (Ca2+)
* Magnesium (Mg2+)
In health care settings, people often omit the word “ion” when discussing electrolytes, referring to potassium as
“potassium” for example.

Question 4

All bodily fluids contain?

Answer 4

Electrolytes, and different locations normally contain different concentrations of electrolytes that are necessary for optimal function.

Question 5

What are the three processes that maintain physiological balance of body fluids and electrolytes in a dynamic interplay?

Answer 5

1. Intake and absorption
2. Distribution
3. Output

Question 6

What is intake and absorption?

Answer 6

Refers to the addition of fluid and electrolytes to the body (intake) and their movement into the blood (absorption).

Question 7

What is distribution?

Answer 7

Process of moving fluid and electrolytes between various body fluid compartments including cells (intracellular) and outside the cells (extracellular).

Question 8

What does extracellular fluid compartment include?

Answer 8

• Fluid between the cells (interstitial)
• Fluid inside blood vessels (vascular)

Question 9

What is output?

Answer 9

Removal of fluid and electrolytes from the body, through normal or abnormal routes.

Question 10

What is the purpose of optimal fluid and electrolyte balances?

Answer 10

Keeps the volume, osmolality, and electrolyte concentrations of fluids in the various body fluid compartments within their normal physiological ranges.

Question 11

What is the scope of fluid and electrolytes?

Answer 11

One either has optimal balance or an imbalance of fluid and electrolytes. Fluid and electrolytes imbalances can be too little, too much, or misplaced.

Question 12

What are two aspects of conceptual fluid balance?

Answer 12

• Extracellular volume
• Osmolality
  Electrolyte balance requires separate consideration.

Question 13

Extracellular fluid volume, bodily fluid osmolality, and plasma electrolyte concentrations each can be visualized as a continuum with what three categories?

Answer 13

1.Optimal balance
2 & 3. Impaired balance

Question 14

What are the three physiological process whose interplay creates fluid and electrolyte imbalance?

Answer 14

1. Intake and absorption
2. Distribution
3. Output

Question 15

What characteristics must be present for optimal balance of fluid and electrolytes?

Answer 15

• Intake and absorption of fluid and electrolytes match the output of fluid and electrolytes
• Volume, osmolality, and electrolyte concentrations of fluid in the various body fluid compartments are within their normal ranges.

Question 16

What must happen to maintain optimal fluid and electrolyte balance?

Answer 16

Output must be matched by appropriate intake and intake must be absorbed.

Question 17

What are the routes of intake and absorption?

Answer 17

The most common route of fluid and electrolyte intake is oral. Other routes include:
* Intravenous (IV) administration
* Insertion into the rectum
* Introduction through nasogastric or other tubes into the gastrointestinal (GI) tract
* Instillation into body cavities
* Infusion into subcutaneous tissues (hypodermoclysis) or bone marrow (intraosseous)

Question 18

What can be manipulated deliberately to maintain fluid and electrolyte balance?

Answer 18

The amount and type of intake

Question 19

What are two strong influences of fluid intake?

Answer 19

• Habit
• Thirst – most important stimulus to thirst is increased osmolality of body fluids, although dry oral mucous membranes, angiotensin II, angiotensin
  III, and arterial baroreceptor stimulation during severe hypovolemia also trigger thirst.

Question 20

What route does not necessarily have to absorb the fluid and electrolytes into the bloodstream?

Answer 20

Intravenous (IV) – because they enter the bloodstream directly.

Question 21

Absorption is especially important to consider for what route?

Answer 21

Oral intake of electrolytes Ca2+ and Mg2+, which have specialized absorption mechanisms in the intestines

Question 22

What is distribution?

Answer 22

After fluid and electrolytes enter the body, they are distributed to various body compartments. Normal fluid and electrolyte distribution is necessary for optimal function.

Question 23

What is filtration?

Answer 23

Filtration distributes the extracellular fluid between the two major extracellular compartments:
* Vascular
* Interstitial
The process of osmosis distributes water between ECF and cells because of osmotic forces. Numerous factors
distribute electrolytes between ECF and electrolyte pools.

Question 24

What is fluid distribution between vascular and interstitial compartments?

Answer 24

Occurs by filtration, the net result of simultaneous opposing forces at the capillary level. The two forces are:
* Hydrostatic pressure – pushes fluid out of its compartment
* Colloid osmotic pressure – caused by large protein particles in the fluid, pulls fluid into the compartment.

Question 25

What is osmosis?

Answer 25

Movement of water across a semipermeable membrane that separates compartments with different concentrations of particles. Occurs almost instantaneously when the osmolarity of one side changes and this rapid equilibration keeps the ECF and intracellular fluid at the same osmolarity.

Question 26

What is osmolarity?

Answer 26

Degree of concentration. Technically, it is the number of particles per kilogram of water.

Question 27

What is electrolyte distribution?

Answer 27

Numerous opposing factors influence distribution of electrolytes between the ECF and the electrolyte pools. Unusual amounts of factors that shift electrolytes can alter their distribution and cause plasma electrolyte deficits or
excesses.

Question 28

What is output?

Answer 28

The normal excretory routes of fluids and electrolytes are:
* Renal (urine) – provides the largest output of fluids and electrolytes in normal circumstances.

    ➢ Aldosterone regulates renal excretion of Na+ and water (isotonic fluid). Increases renal excretion of K+ directly and probably Mg2+ indirectly.
   ➢ Antidiuretic hormone (ADH) regulates excretion of water

• Gastrointestinal (feces)
• Through the skin (insensible perspiration and sweat)
• Lungs (water vapor)

Question 29

What are age related differences for infants and children?

Answer 29

Neonates and infants are not able to communicate thirst except by crying, which can affect their fluid intake if their caregivers are not vigilant.

They also have a high percentage of body weight as water and more extracellular fluid than intracellular fluid. This changes with the growth of the infant and creation of more cells.

Since neonates and infants have a large body and lung surface area compared to their body mass, they have a higher fluid exchange ratio than any other age group. They have immature kidneys that have little reserve capacity, reaching maturation during childhood.

Question 30

What are the age related differences for older adults?

Answer 30

The thirst sensation is blunted in older adults. The osmolarity of their body fluids can rise higher before older
adults become thirsty, so they may have a decreased fluid intake.

They also have decreased lean body mass, which decreases the percentage of their body weight that is water compared to that of young and middle-aged adults.

Even with working kidneys, they have decreased renal reserve due to decreased number of nephrons that occurs with normal aging.

Question 31

What are the populations at risk of fluid and electrolyte imbalance?

Answer 31

The very young and the very old.

• Preterm infants are at a great risk for fluid and electrolyte disturbances due to very immature kidneys and large surface area of skin and lungs; the
  degree of risk is related to weight and gestational age at the time of birth.
• Term infants and young children are also more at risk than adults due to immature kidneys, high metabolic rate, and large fluid exchange ratio.
• Older adults have a blunted thirst sensation and decreased renal reserve due to a normal gradual loss of nephrons.

Question 32

What are the individual risk factors of fluid and electrolyte imbalance?

Answer 32

Greatest risk factors are associated with serious injury or significant health conditions It is useful to think about risk factors in terms of what the disease or behavior is causing rather than focus on the disease itself.

See Box 8-3 Common Risk Factors for Fluid and Electrolyte Disturbances.

Question 33

What is focused on for history assessment of fluid and electrolytes?

Answer 33

In addition to focusing on the renal, endocrine, or other conditions, that may cause the fluid or electrolyte imbalance, the history must include questions regarding fluid and electrolyte intake and output.

Medication history is important because many supplements and medications influence fluid and electrolyte balance

Question 34

What are the examination findings for fluid and electrolytes?

Answer 34

Astute clinicians incorporate assessment for the individual’s
most likely fluid and electrolyte imbalances into every physical assessment rather than waiting until the signs and symptoms become severe.

See Table 8-1 Clinical Manifestations of Disrupted Fluid Balance and Table 8-2 Clinical Manifestation of Disrupted Electrolyte Balance.

Interpretations of assessment findings may be complicated by the presence of acid-base imbalances.

Question 35

What are diagnostic tests?

Answer 35

Laboratory tests performed on blood samples provide the definitive diagnosis for osmolality and electrolyte
imbalances.

Normal ranges are provided in Table 8-1 and Table 8-2.

Question 36

What is primary prevention of fluid and electrolytes?

Answer 36

Based on the principle that intake must balance output to maintain optimal fluid and electrolyte balance.

Example:
1. Teaching people to replace fluid output from vomiting and diarrhea with Na+ containing fluid can prevent extracellular volume deficit.

2. Teaching people who take potassium-
   wasting diuretics how to increase their dietary K+ intake and the importance of taking prescribed K+ supplements
   helps prevent hypokalemia.
3. Teaching for people who have
   oliguric renal disease focuses on decreasing their intake of Na+, K+, and Mg2+ because their output is decreased.
4. Teaching people how to maintain optimal fluid and electrolyte balance.

Question 37

What is secondary prevention of fluid and electrolytes?

Answer 37

Screening to detect disrupted fluid and electrolyte balance is not performed in general population except as part of a
routine physical exam that would include assessment for physical signs of ECV excess or deficit and standard
laboratory tests include measurement of serum Na+, K+ and Ca2+ levels.

Question 38

What is fluid and electrolyte support as a collaborative intervention?

Answer 38

ECV deficit, hypernatremia, and plasma electrolyte deficits are treated by fluid or electrolyte replacement and by treatment of any underlying cause.

ECV deficit requires isotonic Na+ containing fluid, hypernatremia requires water, and electrolyte deficit usually requires replacement of deficient electrolytes.

A person with clinical dehydration will need both isotonic Na+ containing fluid and extra water which can be given orally, through IV, or through other
routes.

ECV excess, hyponatremia, and plasma electrolyte excesses usually involve some type of restriction.

Nurses need to be sure that people know the reason for the restriction and receive culturally appropriate teaching
regarding how to change their diet or fluid intake.

Medications may be used as well to treat ECV excess, hyponatremia, and plasm electrolyte excesses.

Question 39

What is medication management as a collaborative intervention?

Answer 39

These medications are directed towards various goals:
* Treat the underlying cause (ex. Antiemetic for imbalances due to vomiting or vasopressin for ADH
deficiency)
* Increase the output of fluid or electrolytes (ex. Diuretics for ECV excess or sever hyperkalemia)
* Shift electrolytes into their pools to decrease plasma concentration (ex. Insulin and glucose for acute hyperkalemia or calcitonin for acute hypercalcemia)
* Counteract life threatening effects of imbalance (ex. Calcium salts to counteract the effect of hyperkalemia on cardiac function)

Medications that can contribute to the individual’s fluid and electrolyte imbalances must be discontinued or their dosage should be modified.

Question 40

What are independent nursing interventions as a collaborative intervention?

Answer 40

Interventions to provide safety and comfort are foundational for people who have fluid and electrolyte imbalances.
Example: safety is a high priority for patients with decreased levels of consciousness from osmolality
imbalances or substantial muscle weakness from sever hypokalemia. Comfort measures are important for people who need to restrict fluid or Na+. People with fluid restrictions should have interventions such as:
* Performing frequent oral hygiene
* Lubricating the lips
* Keeping fluids out of sight
* Providing the allowed liquids in insulated containers
* Instructing people to swish fluids in their mouth before swallowing promote comfort during fluid restriction.
Individuals who need to restrict Na+ intake because of ECV excess can be comforted with the knowledge that salt taste often changes after a few weeks of salt restriction so that the food that seems tasteless at first probably will have more enjoyable flavor in a few weeks. Learning about herbs and spices also is useful for individuals with restricted sodium.

See Box 8-4 Nursing Interventions for People with Disrupted Fluid and Electrolyte Balance.

Question 41

What are interrelated concepts for fluid and electrolytes?

Answer 41

• Nutrition
• Mobility
• Hormonal regulation
• Cognition
• Perfusion
• Gas exchange
• Acid-base balance
• Elimination