Fluids & Electrolytes ppt (chap 24, 25) Flashcards
(83 cards)
Define intracellular fluid
fluid within the cells
Define extracellular fluid
all other body fluids
Define interstitial fluid
fluid that lies between cells and tissues
Define intravascular fluid
plasma within blood vessels
Define transcellular fluid
cerebral spinal fluid, synovial fluid, peritoneal fluid
Define osmosis. What are some characteristics of osmosis?
the movement of water across a semiperiable membrane. Fluid moves from LOW concentration to HIGH. Maintains fluid EQUILIBRIUM between fluid compartments
Define osmolality
the concentration of solute (Na, K, Glucose, Urea) in a solvent (body water), reflects hydration status.
What is the normal rage of serum osmolality?
280 – 300 mOsm/kg H20
What is the normal rage of urine osmolality?
50-1200 mOsm/kg H20, random
Define low serum osmolality. What causes a low serum osmolality?
higher than usual amount of water in relation to amount of particles dissolved. causes include overhydration, edema, SIADH, renal failure, diuretic use, adrenal insufficiency, high fluid intake.
Define high serum osmolality? What causes a high serum osmolality?
less than usual amount of water in relation to amount of particles dissolved. causes dehydration, water loss, diabetes insipidus, hyperglycemia, hyperosmotic, hyperglycemic syndome, hypernatremia.
What causes a low urine osmolality?
fluid volume excess, diabetes insipidus, acute renal failure, diuretic therapy
What causes a high urine osmolality?
fluid volume deficit, SIADH, increaqsed ibuprofen use, dehydration, acidosis, shock
What causes a low urine osmolality?
Fluid volume excess, diabetes insipidus, acute renal failure, diuretic therapy
What are the starting forces?
capillary hydrostatic/oncotic pressure, interstitial hydrostatic/oncotic pressure
Which starting forces shift fluid into the capillary? When can you see this?
capillary oncotic and interstitial hydrostatic. can be seen with HHANKS.
Which starting forces shift fluid out of the capillary? When can you see this?
capillary hydrostatic and interstitial oncotic. can be seen in HF and cirrhosis
How is fluid hemostasis regulated?
by thirst and renal excretion
Explain how thirst regulates fluid hemostasis.
thirst is the primary regulator of water intake. the hypothalamus is stimulated by decreased fluid volume, increased serum osmolality, and high sodium balance
Explain how the nervous system regulates fluid balance.
baroreceptors (detect pressure changes) pick up changes is arterial blood pressure and make changes as necessary. vasodilation and increased UO with high BP and vasoconstriction and decreased UO with low BP.
Explain how aldosterone regulates fluid balance.
Low Na leads to an increase in ACTH which causes an increase in aldosterone. Aldosterone causes the body to hold onto Na and H2O increasing the fluid volume and BP (potent vasoconstrictor).
Explain how ADH regulates fluid balance.
THE NO PEE HORMONE (tells body to hold unto H2O).
Explain how RAAS regulates fluid balance.
RAAS leads to the release of angiotensin II which causes vasoconstriction which increases BP & perfusion. Aldosterone holds unto NA & H2O.
What questions do you ask about the history of a pt w/ fluid electrolyte balance?
Does the pt have injury, disease, medications, dietary restrictions, total intake vs total output that alters f/e balance?