All Episodes C2B Podcast 23 - Hyperkalemia
Nov 19, 2019
Potassium is primarily an intracellular ion responsible for
maintenance of the resting membrane potential for normal cell
Serum measured potassium is typically between 3.5 and 5.0
Serum K greater than 5.0 mEq/L is generally considered the
threshold for hyperkalemia.
Potassium is mostly excreted via the kidneys, and the "classic"
hyperkalemia patient is one who has missed several dialysis
appointments complaining of paralysis or diffuse weakness.
Causes of HyperK
Most commonly, renal failure.
Other acid-base disturbances
RAAS or ACE inhibitors
Effects of HyperK
Most drastically affect cardiac myocytes
Conduction between myocytes is depressed, leading to slower
conduction and widened QRS complexes, however, the rate of
repolarization is increased.
Leads to ominous “sine wave” pattern on ECG.
May produce classic tall, “peaked” T waves on ECG.
Stepwise ECG changes in hyperkalemia:
5.5-6.5 mEq/L - Peaked T Waves
6.5-7.5 mEq/L - P waves amplitude becomes smaller and PR
7.5-8.0 mEq/L - QRS becomes wide
. Patients may have a critical K with no
changes on the ECG. ECGs are not always sensitive for
hyperkalemia Skeletal muscle tissue is also sensitive to hyperkalemia, and
patients may present with weakness or paralysis as a
Nondescript symptoms such as muscle cramps, diarrhea, vomiting,
nausea, and focal paralysis may also be present - but are also not
Prioritized by a strategy of:
Stabilization of cardiac cell membranes
Shifting potassium back into the cells
Calcium (Chloride or gluconate) administered to stabilize cell
Stabilizing effect is transient and relatively short
Calcium Chloride contains roughly 3 times the amount of
elemental calcium as compared to Ca gluconate, but is associated
with severe complications if extravasation occurs.
Effects (narrowing of QRS complex, return of more hemodynamic
stability) occurs within minutes
Calcium Chloride - generally, 1 gram is administered over 3
Calcium Gluconate - 1 gram over 2-3 minutes
Repeat either q5min
Albuterol / Beta 2 agonists
These act on beta 2 receptors to assist in moving potassium
back into the intracellular space
Albuterol - 10-20mg (inhalation), with most effect noted in 30
Drives K back into the cells (shift)
Generally administered with dextrose unless the patient’s BGL
is below 250mg/dL
10 units IVP followed by 25G dextrose
Incidence of hypoglycemia is high, and this therapy should be
Treating reversible cause
d/c RASS or ACE inhibiting medicaitions