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Flashcards in Nephro - K - Online MedEd Deck (10):

Normal K - values

Hospitalized patients: 4-5
Deranged K --> death (very narrow range of K)
Intact K is taken care by normal kidneys


Hyperkalemia - differential

1) Low Aldo state - ACEi, ARB, aldosterone antagonists - side effects of increasing K
2) Iatrogenic - give K
3) Ingestion (i.e. citrus) - most likely with CKD
5) Artifact - hemolysis


Hyperkalemia - look for what testing?

EKG (K = potassium)
Hyperkalemia - peaked T waves, QRS widen
Can also cause heart blocks
-If not corrected, will get sine wave EKG, and might not recover


Hyperkalemia - what to do first?

Recheck K+ - due to likely iatrogenic
If elevated on recheck --> get EKG
If EKG is bad --> need to intervene asap (emergent) - need to do everything (stabilize, temporize, decrease K)
If EKG is normal --> then this is a stable hyperkalemia (urgent) - decrease K


So if patient has hyperK with EKG changes... what are the interventions?

1) Stabilize - give CaCl IV last a few minutes (stabilize cardiac myocytes)
2) Temporize - want to shift K into cells - does nothing to total body K (so heart can't see it) - insulin and D50 (give insulin to shift, and D50 to compensate for glucose), can also give Na bicarb and Beta agonists - last hours
3) Decrease total body K - eliminate - through urine and stool - i.e. loop diuretics (furosemide for K through urine); kayexalate so eliminate K through stool/diarrhea; can also use dialysis (chronic therapy) - these take a long time; can do acute hemodialysis


Hypokalemia differential - how does it occur

Renal losses - hyperaldo (renal artery stenosis, Conn syndrome), diuretics (loops, thiazides)
GI losses - vomiting, diarrhea


Hypokalemia what to do first?

Check EKG
Some flattening of T waves
-But typically replenish K


So low K... what test to do first?

Recheck blood K
Check EKG
But regardless will replete K
- In practice ppl will jump right to replete K


Repleting K

Oral is better than IV
With peripheral line, cannot go faster than 10mg/hr
Central line: fastest 20mg/hr for fear of cardiac symptoms
10 mg of K will change 0.1


What is the other lab value to check for hypokalemia

-Might be low, so replete with K