Sodium Disorders Flashcards
isotonic solutions
0.9% normal saline
lactated ringer
stays in ECF/vasculature
hypotonic solutions
D5W
D5W + 0.45NS
D5W + 0.9 NS
hypotonic - goes into ALL spaces (essentially giving water)
normal fluid balance water movement
moves freely between intracellular space and intravascular space
responds to hydrostatic pressure
allows for osmotic equilibrium
normal fluid balance sodium movement
confined to extracellular space
kidney fluid balance
detect any hypo perfusion as _____
volume depletion
even if nonexistent
transfer water b/t vascular and interstitial compartments is governed by
osmotic balance
hydrostatic balance
major extracellular cation and anion
cat: Na
an: Cl, HCO3
major intracellular cation and anion
cat: K
an: protein
response to decreased ECF
- ADH release
- Decreases ANP
- Renin Release
- Stimulation of thirst
two systems that respond to decreased ECF
+ time
hemodynamically (immediate) via vasoconstriction (raises BP and HR)
renal (12-24hrs) via ADH release and RAAS activation
ADH
from posterior pituitary
closes aquaporin channels
decreased FREE water excretion
no effect on Na
ANP
decreased urinary sodium loss
released by atrial stretch receptors
aldosterone
RAAS activation stimulates release
decreasing sodium and water
effective hemostasis dependent on
functioning kidneys and afferent sensors
afferent sensors
found in: atria, pulmonary vasculature, carotid sinus, aortic arch, juxtaglomerular apparatus
responds to ECV
ECV
fullness and tension in arterial tree
should be = to ECF if no third spacing present
disorders of ECV
disorders of decreased CO or arterial HoTN
HFrEF (decreased pump and strength) Liver failure (third spacing, decreased liver protein production) Renal failure (third spacing, increased liver protein excretion)
body’s response to this is maladaptive
hypovolemia etiologies
renal water loss (nephrogenic DI)
extra renal loss of water (increase RR, sweating, v/d)
marker of hypovolemia
decreased urine output
HoTN
hypovolemia treatment
fluid replacement is mainstay of tx
0.9% NS or colloid (LR) bc fluids stay in ECF
hypervolemia
intake exceeds excretion, fluid shifts from intravascular to interstitial space due to high capillary hydrostatic pressure (third space)
primary or secondary
retention of Na, water
tx: volume restriction, diuretic
primary hypervolemia
increased ECV, caused by:
Oliguria 2/2 AKI, GN
severe CKD
Primary hyperaldosteronism
Cushings
secondary hypervolemia
decreased ECV
occurs in response to decreased ECV
found in CHF or cirrhosis
decreased perfusion = hold onto water
hypervolemia treatment
diuretics - block Na reabsorption at some point in kidney
TZDs can cause hyponatremia (bc works on last stop in tubule)
may need to use a combo to deal with electrolyte disturbances