How to Calculate Potassium Replacement Therapy using Potassium Tablet and Potassium Chloride Infusion?

[Sweet Orange Juice]

So, as far as I know, to calculate the potassium deficit, the following formula can be used:
Kdeficit (in mmol) = (Knormal lower limit − Kmeasured) × kg body weight × 0.4

But how do we select the dose for Potassium Tablet and Potassium Chloride Infusion?

Can someone give me an example?

Many thanks for the help

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[WheezyBaby]

I don't calculate a K deficit, and the deficit is nonlinear with potassium level so that equation doesn't make much sense to me regardless. Ballpark rule starting dose 20 to 40 meq for adults and 0.5 to 1 meq/kg for kids, assess response and reassess dosing and frequency based on response. Give consideration to renal function, anticipated ongoing losses or not (eg with active diuresis), etc. As far as route, enteral generally preferable if absorption is anticipated to be reliable (eg no ileus, significant bowel edema)

 

[ortnakas]

Street version (not official math version don’t quote me especially on nephro):
10 mEq for every 0.1 deficit with goal 4
Don’t give more than 40 mEq or more than 80 mEq over a few hours without rechecking
PO > IV unless a reason to have poor absorption
Don’t give more than 10 mEq/hr through a peripheral line
If K < 2, think hard about central line so you can replete more efficiently
Don’t forget about mag

 

[Redpancreas]

So, as far as I know, to calculate the potassium deficit, the following formula can be used:
Kdeficit (in mmol) = (Knormal lower limit − Kmeasured) × kg body weight × 0.4

But how do we select the dose for Potassium Tablet and Potassium Chloride Infusion?

Can someone give me an example?

Many thanks for the help

Don't make it complicated. Forget this formula.

1.) 10 mEq = 0.1 K but keep in mind what the poster said about the non-linear relationship. It's more of a piecewise function where in general the lower the K is, the harder it is to correct. So 2.0->3.0 is harder than 3.0->4.0 so be a little proactive when it's on the low 3s especially when something's being done to deplete K. Also like second poster said, replace Mg before K if low.

2.) Give oral unless there's altered anatomy or some reason not to. IV burns and it can only be replaced at a rate of 10 mEq an hr (generally).

3.) Be careful in ESRD patients and patient's with AKI and double check renal function if epic doesn't do it for you. CKD3A that's not active...I wouldn't worry about as much.

That's about the extent of it. Doesn't have to be more complicated than that.

 

[mrbreakfast]

Basically what everyone else said. Just for emphasis:
-10 mEq for 0.1 K. I roughly divide the potassium dose by the creatinine and then give that, though that's a fairly conservative approach.
-Never K through IV unless you have a reason to. It will tie up a line forever - a large percentage of patients can't tolerate 10 mEq/hr.
-If someone's getting potassium, they're also getting a (single) dose of oral magnesium that day. Wouldn't check a mag level unless the K isn't going up.