Iv mag or k+ which do I hang first?

[JenniferG rN]

Recently I had a patient that needed both iv k and iv mag. The patient had one patent iv site. I hung the potassium 1 st because it would take the less time. Then get the mag started. When handing off my patient the RN told me that the mag should go first because it is what the k will stick to. I had not heard this before and am unable to find any information on this. Has anyone else?

[ausrnurse]

I would have given both at the same time (in the ICU), but as you said, it was a flimsy little peripheral line - I would give the K last in that case. K+ is notorious for burning and ruining your IVs.

[Altra, BSN, RN]

JenniferG RN said:

Yes it was a peripheral iv NS @125/' then a 40MeQ mixed In a 250ml bag of NS bag was piggy backed in. W a 2 gram in 50ml NS bag of mag to also run at the same time. The patient was a tough stick and Was only going to the observation unit I didn't see a need to start a second site. Our pharmacists did not recommend running them at the same time d/t possible overload. On a side note ; I'm so thankful I joined this site- there is so much insite, knowledge and comedy. I wish I would of known about this years ago.

40mEq KCl mixed in a 250 bag, you say?

Hmm. Interesting.

[Anna Flaxis, BSN, RN]

Altra said:

40mEq KCl mixed in a 250 bag, you say?

Hmm. Interesting.

I noticed that too, but if you were to y-site it with the NS and run it in over 4 hours, the concentration shouldn't be an issue. I just have a hard time believing that 2g of mag would take more than 4 hours, which was the OP's rationale for running the K+ first.

Definitely some fishy stuff here, but in essence, the answer is the same- run mag first.

[sapphire18]

Umm, if the K+ is 1.9 you need to give that first, that is way way way too low...actually I've never seen below 2. A mag of 1.7 is fine to wait if you really don't want to just give them together.

[Anna Flaxis, BSN, RN]

sapphire18 said:

Umm, if the K+ is 1.9 you need to give that first, that is way way way too low...actually I've never seen below 2. A mag of 1.7 is fine to wait if you really don't want to just give them together.

The OP never told us what the serum K+ was.

The 1.9 came from post #15, which was written by a different member and actually makes my point, that you give the mag first. Go back and re-read it.

[Lev, MSN, RN, NP]

Lev, BS, RN said:

Had the same thing the other day. Mg 1.7 and K 1.9. The previous day, the patient's Mg was 1.9 and K was 1.8. She was given IV potassium and the K barely moved. I gave her 2g Mg yesterday and 800mEq po potassium. Today K was 3.1 and Mg 1.9.

I have to correct myself based on another post.

Day 1: Mg 1.9, K 2.8 - K was repleted IV

Day 2: Mg 1.7, K 2.9 - 2 g Mg was repleted IV, given PO K.

Day 3: Mg 1.9, K 3.1

Still makes the point. I had patient on Day 2. IV potassium lowered the magnesium causing the IV potassium to not be absorbed, at least not initially. Once the Magnesium was replaced IV too, the PO potassium, which I gave after the Magnesium ran, could work. Note: she got 40mg of Lasix on day 2, which I held until I got instructions to give it after the Potassium.

A patient with a K of 1.9...would not be getting PO potassium.

[sapphire18]

I just saw the nemo avatar and assumed it was the OP my bad stargazer...but you still will not wait to correct a K+ of 1.9.

[sapphire18]

\ said:

A patient with a K of 1.9...would not be getting PO potassium.

...Agreed. They would also not be getting 800 mEq of it.

[Anna Flaxis, BSN, RN]

Lev, thank you for clarifying. That does make a lot more sense.

sapphire18 said:

I just saw the nemo avatar and assumed it was the OP my bad stargazer...but you still will not wait to correct a K+ of 1.9.

No, you wouldn't wait, but that's not really the point. The point is that you can pour all the potassium you want into the patient, but it's not going to correct the problem unless you correct the magnesium first.

[harrird]

Interesting thread. Got a better understanding with the colander analogy. Thanks.