Treatment of hyperkalemia??

[Z28BLKCAM]

There are many ways of treating ACUTE hyperkalemia.

1) D50/Insulin to stimulate the Na/K (3Na out and 2 K in) pump, D50 to prevent hypoglycemia

2) HCO3 (H+ shifts out of the cells to buffer the alkalosis, and, in exchange, K+ shifts into cells)

3) Beta 2 adrenergic receptor agonist e.g., Albuterol (stimulates the Na/K pump)

4) Hyperventilation (H+ shifts out of the cells to buffer the alkalosis, and, in exchange, K+ shifts into cells

5) Kayexalate

6) Dialyze

7) CaCl

My question is how exactly Calcium (calcium chloride) works?

I understand when you are hyperkalemia, the diffusion gradient for K+ is reduced, because of this, the resting potential is diminished so the cell depolarizes. By giving CaCL, the threshold moves away from the resting potential, thereby decreasing excitability. Giving calcium very quickly protects the heart from hyperkalemia. BUT exactly how Ca does that? Other books states that this treatment does not decrease your intravascular K levels. When you give Ca it also seems to bind to the voltage-gated Na+ channel channels, causing them to close, preventing depolarization, is this the mechanism of how Ca works in hyperkalemia?

Any input is appreciated

Thanks in advance

Z28blkcam

[sandman]

An increase in extracellular Ca will decrease the permeability of Na channels. The Ca binds to the sodium channel repelling Na ions. In the gated Na channel, the Ca ions bind to the gate making it more difficult to produce the confirmational change which opens the channel.

So in hyperkalemia, where less K is diffusing out of the cell (raising the resting membrane potential), we give Ca to increase the threshold potential (stabilizing the membrane)

You are right, Ca does nothing to decrease hyperkalemia.

[Z28BLKCAM]

Thanks Sandman!!

Now I am ready for round 2 of the PIMPING!!

Z28BLKCAM

[Roland]

is deliberately induced because it makes the threshold potential LESS negative, helping to counteract the affects of the hyperkalemia. Kind of like urinating on hot coals that are burning your foot, it may decrease the burning, but the coals are still hot , and now your foot will smell like urine, but just maybe you can avoid a bad burn.