Hypokalemia

What is normal adult total body K+

50-55 mMol/kg

Most potassium goes to which organ

Kidney

Aldosterone secretion is modulated by which ion?

Potassium

B2 adrenergic stimulation (epi) ______ intracellular K

increases

Acidosis effect on K

increases plasma K—> causes K to move out of cells

Alkalosis effect on K

Reduces plasma K —> causes potassium to move into cells

Aldosterone and Insulin prevent ___kalemia

Hyperkalemia

Mild hypokalemia serum potassium

3.1-3.5

Moderate hypokalemia serum potassium

2.5-3.0

Severe hypokalemia serum potassium

<2.5

Which is more acutely dangerous, hypokalemia or hyperkamia

Hyperkalmia

Causes of hypokalemia

Poor diet

Intracellular shift (insulin, B2 agonist, caffeine)

GI loss (vomiting, diarrhea)

Urinary losses (hyperaldosteronism, magnesium deficiency)

Symptoms of Hyokalemia

Constipation

Muscle weakness in lower extremeties

Cardiac effects of hypokalemia

U-waves

How to manage hypokalemia between 3-3.5

Dietary K

PO supplement if on digoxin

How to manage hypokalemia between 2.5-3

PO supplements

How to manage hypokalemia between 2-2.5

PO supplements promptly

consider IV if they cant do PO

How to manage hypokalemia under 2

IV supplement IMMEDIATLY !

What is the best potassium supplement form

Microencapsulated capsules

What is the preffered potassium supplement

KCl

When could you use potassium bicarb?

When they are also bicarbonate deficient (metabolic acidosis)

When could you use potassium citrate ?

For kidney stones, not really as a K supplement

When could you use potassium phosphate?

When they also have a phosphate deficit

10mmol of IV or oral K increases serum K by ________

0.1 mmol/L

Is IV or PO K supplement prefferd?

Use PO when possibible, and divide dose TID or QID with food

Is diet changes good for when you need a quick K increase?

No

Cautions for potassium replacement

Decreased renal function

Trimethoprim (TMP in antibiotics)

Heparin

ACE-I or ARB

Beta 2 blocker

K sparing diuretic

THESE ALL MIGHT RAISE POTASSIUM LEVELS HIGHER THAN EXPECTED

What IV fluid should you use for IV potassium?

NORMAL SALINE- NO DEXTROSE BC THEY STIMULATE INSULIN WHICH WORSENS HYPOKALEMIA

Infusion rate for K

10-20 mMol/hr via central vein