fluids and electrolytes Flashcards
Sodium content determines ?
ECF volume status
Sodium concentration determines
ICF volume status
when is RAAS activated
- Decreased BP
- Decreased GFR
excretion of water is controlled by
ADH
What triggers ADH release
Hypernatremia
ECF vol depletion
non-osmotic stimuli
what drugs can trigger ADH release
HCTZ, NSAIDs, anti-epileptics, SSRIs
ECF volume expansion means
sodium content is increased
RAAS activation results in
decreased sodium excretion
in heart failure what happens to sodium
more sodium in and less sodium out (less excretion due to RAAS activation)
how is ECF volume expansion treated? as in heart failure?
- increase Na excretion - diuretic
- decrease intake
- Block RAAS - improve cardiac function
someone who is very dehydrated should receive what type of solution?
ORS - hYPOTONIC solution
when would you need massive amounts of isotonic saline as rehydration therapy?
- cholera with profound hypotension
- septic shock
- DKA
Hyponatremia is ALWAYS the result of
WATER retention
why would someone retain water
ADH is acting
no kidney function - no GFR
- no osmoles to excrete
If hyponatremia presents rapidly, patients can get
cerebral swelling - correct rapidly
If hyponatremia is slow onset, patients may be
asymptomatic
Treating hyponatremia
- reduce water intake
- remove underlying cause of ADH release
- rapid correction if acute
- Treat slowly if chronic and severe
common causes of hypernatremia
- failure to drink fluids
- excess losses - hyperglycemia -
- or diabetes insipidus - central/nephrogenic
Treating hypernatremia
give water!
treating hyperkalemia 4 principles
- stabilize myocardium
- shift K into cells
- excrete potassium
- hemodialyze
