NSG 300 TOPIC 6: FLUID AND ELECTROLYTE BALANCE IN NURSING
PRACTICE
where is fluid distributed in the body
fluid surrounds all cells in the body and is also inside cells
what are the characteristics of body fluids
-fluid amount (volume)
-concentration (osmolality)
-composition (electrolyte concentration)
-degree of acidity (pH).
what is the recommended fluid intake
~2300mL/day
when is the thirst mechanism in the hypothalamus activated?
when plasma osmolarity increases (osmoreceptor-mediated thirst) or the blood
volume decreases (baroreceptor-mediated thirst and angiotensin II and III mediated
thirst)
fluid distribution
the movement of fluid among its various compartments
extracellular and intracellular distribution occurs by
osmosis
vascular and interstitial distribution occurs
filtration
where does fluid output normally happen in the body
skin, lungs, GI tract, kidneys
insensible loss
Water lost thru the skin (individual is unaware of losing that water)
sensible loss
, loss that is perceived or is measurable. (wound drainage, GI tract, urine)
fluid output is influenced by what hormonal influences
-ADH
-RAAS
-ANPs
When is ADH released?
when dehydrated and body fluids are mor concentrated
what factors increase ADH levels
o Decreased blood volume (dehydration, hemorrhage)
o Pain
o Stressors
o Some medications
what does the RAAS regulate
ECF volume by influencing how much sodium and water are excreted in urine.
it also contributes to regulation of BP
Atrial natriuretic peptides (ANPs)
regulates ECF volume by influencing how much sodium and water is excreted in
urine
-Cells in the atria of the heart release ANP when they are stretched (e.g., by an
increased ECV).
Volume imbalances
disturbances of the amount of fluid in the extracellular compartment
osmolarity imbalances
disturbances of the concentration of body fluids
When is ECV deficit present?
when isotonic fluid is insufficient in the extracellular compartment.
(With ECV deficit, output of isotonic fluid exceeds intake of sodium-containing
fluid.)
PRACTICE
where is fluid distributed in the body
fluid surrounds all cells in the body and is also inside cells
what are the characteristics of body fluids
-fluid amount (volume)
-concentration (osmolality)
-composition (electrolyte concentration)
-degree of acidity (pH).
what is the recommended fluid intake
~2300mL/day
when is the thirst mechanism in the hypothalamus activated?
when plasma osmolarity increases (osmoreceptor-mediated thirst) or the blood
volume decreases (baroreceptor-mediated thirst and angiotensin II and III mediated
thirst)
fluid distribution
the movement of fluid among its various compartments
extracellular and intracellular distribution occurs by
osmosis
vascular and interstitial distribution occurs
filtration
where does fluid output normally happen in the body
skin, lungs, GI tract, kidneys
insensible loss
Water lost thru the skin (individual is unaware of losing that water)
sensible loss
, loss that is perceived or is measurable. (wound drainage, GI tract, urine)
fluid output is influenced by what hormonal influences
-ADH
-RAAS
-ANPs
When is ADH released?
when dehydrated and body fluids are mor concentrated
what factors increase ADH levels
o Decreased blood volume (dehydration, hemorrhage)
o Pain
o Stressors
o Some medications
what does the RAAS regulate
ECF volume by influencing how much sodium and water are excreted in urine.
it also contributes to regulation of BP
Atrial natriuretic peptides (ANPs)
regulates ECF volume by influencing how much sodium and water is excreted in
urine
-Cells in the atria of the heart release ANP when they are stretched (e.g., by an
increased ECV).
Volume imbalances
disturbances of the amount of fluid in the extracellular compartment
osmolarity imbalances
disturbances of the concentration of body fluids
When is ECV deficit present?
when isotonic fluid is insufficient in the extracellular compartment.
(With ECV deficit, output of isotonic fluid exceeds intake of sodium-containing
fluid.)
