Question about treating HYPERkalemia..

[EctopicFetus]

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I had a pt with a K of about 6.0. So my ER attending asks me what I want to do fot this patient. So I tell him..

1) CaCl2 or Ca gluconate
2) D50 with 10 units of insulin
3) NaHCO3

I said that should be sufficcient. He said it probably would be but he likes to give other medicine. So then I said Kayexalate. He said no.. something else. Finally I just gave up. He tells me albuterol and then shows me that it is written in some book. He couldnt tell me how this worked (the mechanism of action) I tried looking it up without any luck. Can anyone fill me in?

Sorry for the long post. 🙁

 

[Espion]

I had a pt with a K of about 6.0. So my ER attending asks me what I want to do fot this patient. So I tell him..

1) CaCl2 or Ca gluconate
2) D50 with 10 units of insulin
3) NaHCO3

I said that should be sufficcient. He said it probably would be but he likes to give other medicine. So then I said Kayexalate. He said no.. something else. Finally I just gave up. He tells me albuterol and then shows me that it is written in some book. He couldnt tell me how this worked (the mechanism of action) I tried looking it up without any luck. Can anyone fill me in?

Sorry for the long post. 🙁

Supposedly it will increase endogenous plasma insulin concentration. Oh yeah...beta-agonist...

I never would have thought of that. Heh, I would have answered "dialysis!"

 

[lindyloohoo]

HA! I just had a talk on hyperkalemia this morning! 10 mg albuterol nebs can be given because it's a b-agonist. b-agonists cause K+ to move into cells (epi and insulin do the same thing) This 10 mg nebs is a higher dose than that given for bronchoconstriction. b-agonists (albuterol and isoproterenol) can also be given parentally, although not very often and albuterol is not available for this use in the US.

My attending said that all of the things you mentioned are done first, with kayexalate given as late a possible because it's a nasty drug (causes diarrhea bad enough pts will recognize you years later as the doctor that gave me the medicine that kept me on the toilet for a long time) Dialysis and kayexelate actually remove K+ from the system where as the other tx (insulin+glucose, b-agonists, NaHCO3) move the K+ from outside to inside of cells.

hope that helped

 

[Idiopathic]

Albuterol for hyperkalemia is one of those USMLE step 1 things, I think...yes, it is a B-agonist and as such will push K into cells, but calcium gluconate is always given in cases of severe hyperkalemia to protect the heart. Your other treatment plan was correct,

 

[EctopicFetus]

Thanks for the help. as far as the Ca Gluconate.. i knew it was for the cardioprotective effects..

So to be clear does it increase the Epi and insulin in the blood which then decreases K? Or does it have a different mechanism of action?

Someone else told me that it could be due to the effect of vasodilation which then allows the kidney to dump more K. I dont think that this is correct.

Anyhow.. can someone be clear on the MOA?

 

[14022]

calcium has NO effect on potassium homeostasis

too much potassium in the blood reduces the potassium gradient (and thus the membrane potential) at the myocyte membrane, thus decreasing the intensity of the conducted action potential and weakening the contraction of the heart

calcium has a direct effect on cardiac myocyte contraction thus the higher the calcium concentration in the blood, the stronger the contraction of the heart

so if youre hyperkalemic, you can stablize the heart by making yourself hypercalcemic until the hyperkalemia can be resolved by various methods

-insulin, increased blood pH (ie, bicarb), and beta agonists push K into cells
-kayexalate makes the potassium come out your anus

-important point...and it always seems to show up on tests...remember if your hyperkalemic and normoglycemic, you need to give dextrose with the insulin and do routine accuchecks to make sure you dont get hypoglycemic

 

[Mumpu]

IIRC, albuterol has a direct effect on driving K into cells -- not mediated through insulin or epi.

Kidney flow is regulated by prostaglandins (afferent) and angiotensin II (efferent). I don't think beta-2 receptors are even present in the kidney in significant amounts.

My understanding of the standard protocol is what you wrote in the original post.

 

[DocWagner]

Just to add a bit, (though I probably wouldn't go full court press on a K of 6...that really is nothing to sweat over unless EKG changes) using CaCl theoretically acts faster than Ca Gluconate because of the size of the molecule, so those in EM use CaCl in a drip unless urgently needed.

Also interesting enough, xopenex has the same effect as albuterol (why you would use it is beyond me unless the patient is already tachycardic and jittery).

Also, generally the dose of insulin is based upon weight (.1unit/kg with an upper limit of 10 in theory)

 

[Mumpu]

Doc makes a good point. Step 1 in your management should be to check the ECG for signs of hyperkalemia.

 

[Trichobezoar]

yeah, Beta 2 agonists drive K into cells. I think dialysis is another option.

I had a pt with a K of about 6.0. So my ER attending asks me what I want to do fot this patient. So I tell him..

1) CaCl2 or Ca gluconate
2) D50 with 10 units of insulin
3) NaHCO3

I said that should be sufficcient. He said it probably would be but he likes to give other medicine. So then I said Kayexalate. He said no.. something else. Finally I just gave up. He tells me albuterol and then shows me that it is written in some book. He couldnt tell me how this worked (the mechanism of action) I tried looking it up without any luck. Can anyone fill me in?

Sorry for the long post. 🙁

 

[Seaglass]

Yeah, something that no one has really mentioned yet is that insulin, albuterol, bicarb, etc. are really only temporizing approaches to hyper-K. If their K is really up they either need to be dialyzed or get Kayexelate.

 

[Idiopathic]

Kidney flow is regulated by prostaglandins (afferent) and angiotensin II (efferent). I don't think beta-2 receptors are even present in the kidney in significant amounts.

The RAAS system is mainly a B-1 mediated system, present in the kidney. There could be some very mild crossover between albuterol and B-1, but this wouldnt be an efficient way of removing K+, even though aldosterone would elevate.

 

[oldbearprofessor]

Just to add a bit, (though I probably wouldn't go full court press on a K of 6...that really is nothing to sweat over unless EKG changes) using CaCl theoretically acts faster than Ca Gluconate because of the size of the molecule, so those in EM use CaCl in a drip unless urgently needed.

Well, to clarify a bit, the problem with the gluconate is that it needs a first pass metabolism to remove the gluconate in the liver to liberate the free calcium ions. This first pass is not needed by the chloride salt. In neonatology, since severe liver failure is uncommon, I have generally taught that you should use the first thing available. In other words, if you have the chloride salt, use it, if not (and most of our drips are gluconate so often it is more rapidly available), go ahead and use the gluconate. In my clinical experience, the difference is only seconds in terms of their action in babies. Usually, this gives us about 10 minutes to give more definitive therapy or a second dose can be given. By the way, remarkably, preterm babies in particular can often (but not always) tolerate serum potassiums of 8.0 or a bit higher before developing an arrhythmia.

Here's a ref for the chloride/gluconate issue. Davey and Caldicott: Emerg Med J 2002; 19:92-93

Regards

"oldbearprofessor"

 

[roja]

Management of hyperkalemia:

1-check ekg
2- check lab.. (is it hemolyzed? If it came from a small 24g needle or sat in the lab for long, it could be hemolyzed)
3- if no ekg changes, you don't need to dump all the calcium, etc... especially only at six. Maybe give some kayexolate to make the medicine people feel better.
4- if the problem is the patient missed dialysis, and no ekg changes, arrange for dialysis..
5- temporize if EKG changes or unstable...


A key point to remember about abnormal lab values in the ED- you don't necessarily need to treat them immediately if there are no symptoms etc.... (ie, youd on't have to dump insulin on someone just because thier FS is 270)

 

[pikachu]

One of my residents shared a nice mnemonic for tx of hyperkalemia with me last year. It is more or less in order, with dialysis as last-resort treatment.

"C BIG K Die"
C = Calcium gluconate
B = B agonist
I = Insulin
G = Glucose
K = Kayexelate
DIe = Dialysis