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The eternal K+ debate


Specializes in Critical Care.

I have always heard that oral K+ is quicker and "better" to give than IV. I worked for a long time in a facility where the policy was to use oral unless contraindicated or denied by MD order. All patients got 20 meq po according to K+ level every couple hours or so. Our IV K+ was 10 meq over 1 hour x4 or 6 depending on level, and if by central line, the limit was over a half an hour if the need was critical.

So now I'm at a facility where their policy doesn't state a preference either way, and the nurses give 40 meq over 1 hour and repeat in 6 hours if needed. Thats the only dose the riders come in...40 meq in 100ml NS. My mind was blown - that seemed like a huge amount to me. Thing is, its an MICU and everyone has PICCs, so its always given IV. I give the oral solution if it falls on me to do it - now, if it gets started IV, I continue it that way, of course. And if they're intubated, I put the oral down the tube.

I've been looking online at articles and standard of care recs, but found nothing so far, although I'll keep looking. But I wanted to poll others and see what everyone else thinks..and if I am wrong, to correct me. :)


Specializes in CCU, med/surg (cardiac/tel). Has 13 years experience.

:no:In our hospital (I work in CCU) we replace K+ both po and iv depending on what the dr orders, but iv K+ is never to be stronger than 10meq over an hour. If the pt has a central line we can give in 50cc of fluid for pt in CHF, but still to be ran over an hour. I guess if pt has a such a critical low K+ that it is causing a lethal arrhythmias it could be given faster but not ever seen it if the 5 yrs I have been a nurse.

we give mostly IV KCl (only through central line though). our [] is 20mEq/50cc, and we give as much as 20mEq/hr. right now im replacing 80mEq over 6 hrs..

ghillbert, MSN, NP

Specializes in CTICU. Has 20 years experience.

Most protocols I have seen say that potassium should be replaced orally as a first line intervention "where clinically feasible". If it has to be given IV it should be given at the rate ordered by the doctor.

You should have a hospital policy/procedure about potassium administration - I would check with your pharmacy.

I would think the docs at a minimum should be ordering (for example) "KCL 10 mEq infused over 1 hour".

Having worked on a unit where we had a patient death after inadvertent bolus of KCL, I just don't understand how some people are so blase about the potential danger.


Has 30 years experience.

It has been my experience that oral K covers faster than IV. My concern about giving IV K is that our pharmacy mixes the K coverage in 250ml! Don't they know that heart patients usually need fluid restrictions??!!:banghead: Giving K coverage in 50-100ml can cause severe pain for the patient so we only give those in a central line.

I have seen Lidocaine used in K mixes to reduce the infusion discomfort. Is anybody else doing this?

NotReady4PrimeTime, RN

Specializes in NICU, PICU, PCVICU and peds oncology. Has 25 years experience.

We use both p.o. and I.V. K+. Our peripheral max is 60 mmol/L and our central max is 1:1. We titrate our 1:1's based on hourly serum levels until it stabilizes. We don't treat until it's


Specializes in Critical Care.

I asked another doc (pulmonologist) the other day if elixir was truly the faster way to replace K+ and he said, yes that was correct. He also seemed shocked at the amount this facility uses IV. He said the max he knew of was 20 mEq an hour.

But I cannot find any clinical studies to correlate. Anyone know of any?

ghillbert, MSN, NP

Specializes in CTICU. Has 20 years experience.

Studies to "correlate" what?

There is plenty of info about potassium infusion safety and med error prevention at the JCAHO website.


Specializes in Med surg, Critical Care, LTC. Has 20 years experience.

I hope when you say ..."if they are intubated you put the K+ down the tube..." you mean the NG or Oralgastric tube, not ET.

In our hospital, runs of K+ IV is the preferable way to get the k+ straightened out pronto, each run is 10 mEq in 100ml of NS to run over one hour. Two nurses must verify the medication and sign it off. We usually have a baseline IV running as well, if possible, as K+ can burn while infusing.

We use 20 mEq in 100cc over 1 hour, unless we have only peripheral access, then it's 10 mEq's over 1 hour. We administer and recheck until K+ in greater that 4.0.

If serum K+ is 3.6-4.0 we replace with a 20 rider, if it's 3.0-3.5 we use 40. Less than 3.0, we start replacing and call the MD. But we still administer as above.

why do you replace K+ if the serum level is 3.6-4.0? what is your target level?


greater than 4.0. we use the same protocol on most of our ICU pt.'s, and ALWAYS for our cardiac pt.'s, unless, of course their creatinine is high or they are dialysis pt.-then it may differ.


Specializes in Med surg, Critical Care, LTC. Has 20 years experience.

Sometimes K+ can be high in dehydrated patients, even those with N/v. When you re-hydrate them, the K+ can drop, so it initially registered artificially high, when it is actually low. That is one reason. H&H can be the same thing. Always check the patients BUN/Creat when check the other values - keep watch on urine output too.

cardiacRN2006, ADN, RN

Specializes in Cardiac.

I have seen Lidocaine used in K mixes to reduce the infusion discomfort. Is anybody else doing this?

In my MSICU, we use lido if I only have peripherals. Otherwise, we only have 10mEq/50cc bags. We run it at 10mEq/hr.


Specializes in Critical Care.

Thanks for all the responses. I think I didn't clarify exactly what I was questioning, which was if KCL elixir has actually been clinically proven to increase serum levels of potassium quicker and with less need for additional administrations.

It seems to me that in one hours time, 20 mEq elixir is advantageous to 10 meq IV solution, excepting of course that absorption time with elixir administration is obviously delayed. Serum levels of K+ may rise faster with IV administration, but in my experience giving IV "riders" or "piggybacks" will in the end require additional doses, as the K+ levels just don't seem to hold. Oral may take longer to give, with doses being 2 hours apart, but the end result is a K+ level that is more "stable", so to speak.

I'm trying to justify my giving po elixir down the NG/OG tube (no, not the ETT, haha) as being safer, and more clinically advantageous than giving a dose of IV KCL that to me is 1) uncomfortably large - 40 mEq over 1 hour - and 2) is "used up" by the body quicker than in an elixir form.

It seems to me that BID doses of Lasix, or more frequently for that matter, are constantly wasting K and oral KCL, with a slower release preparation, gives a more constant therapeutic effect than a KCL "bolus" as with IV piggybacks.

In the end, it's really about doing what's more advantageous for my patient, so I am wondering clinically what that way is.


Specializes in Paediatric Cardic critical care. Has 6 years experience.

In my unit we give mainly IV kcl, we give 20mmol over half and hour, or 40mmol over an hour. We aim for k of 4.5-5.0 but it's a cardiothoracic critical care. Most our pt's are intubated and dont have NG tubes as we aim to extubate our fast track pt's within 6hours and discharge to the cardiothoracic surgical ward step down bay the next morning(all going to plan); usually they are started on oral K once they are on the ward.

I find that Iv K is more effective at getting the K up and keeping it up as most our post op patients are passing massive amounts of urine post CPB; also they tend to recieve a lot of K in the first 12hours post op.

I also find it easier to tirtate their K levels using IV.

We also do regular 1hourly post op ABG's which has K levels on them so we can keep a close eye.

I guess the thinking is that it is safer giving po K on the wards as there is not such a good staffing ratio and the pt's aren't monitored so closely:)


Specializes in ICU. Has 15 years experience.

For oral replacement we use Sando K but only if the patient can eat/drink or they have an enteral feeding tube and they have been absorbing their feeds.

Most of the time we give K+ as an IV infusion through a central line at say 5 to 10ml per hour (1mmol per ml) but I have seen it used at higher rates.

Sometimes we put k+ in the Lactasol when the patient is on CVVHDF.

ghillbert, MSN, NP

Specializes in CTICU. Has 20 years experience.

melissa, sounds like you're asking about the pharmacokinetics of oral versus IV potassium supplements... probably a good question to check out in a drug book or ask your friendly workplace pharmacist.

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