Fluids & Electrolytes I

Question 1

What is the percentage of total body water (TBW) in females

Answer 1

50%

Question 2

What is the percentage of total body water (TBW) in males

Answer 2

60%

Question 3

What are the factors that TBW depend on

Answer 3

Age
Body muscle/fat content

Question 4

True or false: the TBW can be divided into the intracellular and extracellular fluid

Answer 4

True

Question 5

This accounts for two-thirds of the TBW regardless of the gender; represents the water contained within cells and is rich in electrolytes and proteins

Answer 5

ICF

Question 6

This accounts for one-thirds of the TBW regardless of gender; represents the fluid outside the cell and is rich in electrolytes and bicarbonate

Answer 6

ECF

Question 7

What are some surrogate markers that can be used to assess the ECF

Answer 7

• blood pressure
• mucous membranes
• skin turgor
• cardiopulmonary examination
• level of consciousness

Question 8

True or false: serum electrolytes are routinely measured from the extracellular space

Answer 8

True

Question 9

This is intravascular fluid and represents the fluid within the blood vessels; it is about 8% of the TBW

Answer 9

Plasma

Question 10

This is known as fluid occupying the spaces between the cells: is about 25% of TBW

Answer 10

Interstitial fluid

Question 11

This includes viscous components of the peritoneum, pleural space and pericardium, as well as the CSF, joint space fluid and GI digestive juices. Usually accounts for 1% of TBW

Answer 11

Transcellular fluid

Question 12

This is the accumulation of fluid in a transcellular space

Answer 12

Third spacing

Question 13

True or false: to maintain fluid balance, the total amount of water in should equal the total amount of fluid lost

Answer 13

True

Question 14

What is the difference between sensible and insensible water intake/loss

Answer 14

Sensible - can be measured (e.g. water intake, kidney function)

Insensible - cannot be measured (water from food, metabolism, water loss from skin/resp)

Question 15

This type of fluid loss tends to occur ACUTELY, generally due to the loss of ISOTONIC fluid (proportional losses of sodium and water). Major disturbances in plasma osmolality are NOT COMMON

Answer 15

ECF depletion

Question 16

what are some signs/symptoms associated with decreased tissue perfusion (ECF depletion)

Answer 16

• dizziness
• orthostasis
• tachycardia
• decreased urine output
• decreased central venous pressure
• hypovolemic shock

Question 17

what are some common causes of ECF depletion

Answer 17

• external fluid losses (e.g. burns, hemorrhage, diuresis, GI losses)
• third spacing of fluids (e.g. septic shock, abdominal acites (fluid builds up in abdomen)

Question 18

this type of fluid loss is typically a more GRADUAL, CHRONIC problem compared to ECF loss. represents a loss of HYPOTONIC fluid (more water than sodium lost) from all body compartments. primary disturbance of osmolality is often seen

Answer 18

TBW depletion (dehydration)

Question 19

what are some signs/symptoms of TBW depletion (dehydration)

Answer 19

• CNS disturbances (mental status] change, seizures, coma)
• excessive thirst
• dry mucous membranes
• decreased skin turgor
• elevated serum sodium
• increased plasma osmolality
• concentrated urine
• acute weight loss

Question 20

what are some common causes of TBW depletion

Answer 20

• insufficient oral intake
• excessive insensible losses
• diabetes insipidus
• excessive osmotic diuresis
• impaired renal concentration mechanisms

Question 21

what are the indications for IV fluids

Answer 21

• maintenance of blood pressure
• restoring the ICF volume
• replacing ongoing renal or insensible losses when oral intake is inadequate
• glucose administration (needed for brain function)

Question 22

this type of therapeutic fluids are composed of water and electrolytes, all which pass through semipermeable membranes and remain in the plasma space for shorter periods of time

Answer 22

crystalloid solutions

Question 23

this class of crystalloid solutions has the same tonicity as ICF and do not shift fluids between ICF and ECF

Answer 23

isotonic solutions

Question 24

this class of crystalloid solutions draw water from the ICF to the ECF

Answer 24

hypertonic solutions

Question 25

this class of crystalloid solutions pulls water from the ECF into the ICF

Answer 25

hypotonic solutions

Question 26

this type of crystalloid solution contains no electrolytes. it is isotonic (in the bag). it raises total fluid volume (TBW), helpful in rehydration for fluid loss and dehydration and it is used for treatment of hypernatremia.

Answer 26

5% dextrose in water (D5W)

Question 27

this type of crystalloid solution has electrolyte concentrations of Na and Cl of 154 mmol/L. it is isotonic. it is used as an ECF volume expander as it increases circulating plasma volume when red cells are adequate. it also may be used for shock/resuscitation, fluid replacement in patients with DKA, hyponatremia, concurrent with blood transfusions, metabolic alkalosis, hypercalcemia

Answer 27

0.9% NaCl (normal saline, NS)

Question 28

this type of crystalloid solution has electrolyte concentrations of Na and Cl of 77 mmol/L. it is hypotonic. it is used as water replacement (“free water”) as it raises total fluid volume. may also be used for DKA after initial normal saline solution and before dextrose infusion, used for hypertonic dehydration, sodium & chloride depletion and gastric fluid loss from nasogastric suctioning or vomiting.

Answer 28

0.45% NaCl (1/2 NS)

Question 29

this type of crystalloid solution has electrolyte concentrations of Na and Cl of 513 mmol/L. it is hypertonic. it is used for treatment of severe hyponatremia

Answer 29

3% NaCl (hypertonic saline)

Question 30

this type of crystalloid solution has electrolyte concentrations Na 130 mmol/L, Cl 109 mmol/L, K 4 mmol/L, Ca 1.5 mmol/L and Lactate 28 mEq/L. it is isotonic. it is used as an ECF volume expander as it replaces fluid and buffers pH. also used for hypovolemia due to third space shifting, dehydration, burns, lower GI tract fluid loss and acute blood loss

Answer 30

Lactated Ringers (LR)

Question 31

this type of crystalloid solution has electrolytes Na and Cl of 154 mmol/L. it is hypertonic. it is used for hypotonic dehydration, replaces fluid sodium, chloride and calories, temporary treatment of circulatory insufficiency and shock if plasma expanders aren’t available, SIADH and Addisons Disease crisis

Answer 31

D5NS

Question 32

this type of crystalloid solution has electrolytes Na and C of 77 mmol/Ll. it is hypertonic. it is used for DKA after initial treatment with normal saline solution and half-normal saline solution as it prevents hypoglycaemia and cerebral edema which occurs when serum osmolality is reduced rapidly. this is the most common post operative fluid and is useful for daily maintenance of body fluids and nutrition, and for rehydration

Answer 32

D5 1/2NS

Question 33

this type of crystalloid solution has electrolytes Na 130 mmol/L, Cl 109 mmol/L, K 4 mmol/L, Ca 1.5 mmol/L and Lactate 28 mEq/L. it is hypertonic. it is the same as LR and it provides about 180 calories per 1000 mLs. it is indicated as a source of water, electrolytes, and calories or as an alkalinizing agent

Answer 33

D5LR

Question 34

this type of therapeutic fluid do not dissolve into true solutions and therefore do not pass readily across semipermeable membranes. they remain in the plasma and increase the oncotic pressure (i.e. shifts fluids INTO the plasma compartment). however, the effect is short lived. these are more expensive. they are plasma volume expanders, but have a risk of fluid overload, dilution of plasma proteins and a decrease in hemoglobin concentration

Answer 34

colloidal solutions

Question 35

this is normally produced in the liver and can also be used as a colloidal solution. it distributes throughout the ECF. plasma 1/2 life is 16h.

commercial solutions include 5% ________ which is iso-oncotic and 25% ________ which is hyperoncotic (there is a slight risk of anaphylactic reaction with commercial solutions)

note: this is a human product therefore there is a risk of disease transmission (but it is rare)

Answer 35

albumin

Question 36

this is a colloidal solution which is a synthetic product. it persists for 18-24 hours. less expensive. there is a risk of allergic reaction

Answer 36

Dextrans & hydroxyethyl starches (pentastarch, hetastarch)

Question 37

which electrolytes are mainly found in the ECF?

Answer 37

• Na+
• HCO3-
• Cl-

Question 38

which electrolytes are mainly found in the ICF?

Answer 38

• K+
• PO4-
• Mg+

Question 39

true or false: proteins can cross over between the ICF and ECF

Answer 39

false - usually don’t cross over due to their size