The eternal K+ debate

[MissAnthrope]

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. :)

[Babs0512]

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]

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.

[MissAnthrope]

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.

[anurseuk]

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:)

[MaryAnn_RN]

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]

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.

[gilf7243]

In my hospital we have such a thing that is a standard form to replace potassium called "Potassium protocal" When it is ordered we print the form and fill it out and fax to pharmacy. The dose is based on the patients weight and most recent potassium level. If it is under 3.5 and if they get lasix and some other meds that deplete potassium you mark it on the form. The nurse decides how it would be best administered. Oral, Liquid, IV. We always try oral unless contraindicated. Then we re-check the level after two hours if the original level was under 3.5 otherwise, we wait until morning and re-check it then. As far as wheter IV is better than oral I cannot say. I know it is probably given a lot faster if oral b/c it takes longer for the iv's to get infused. I have never heard of potassium being given any other way then 10meq at a time IV. It is very irritating to the tissues. I hope if given this way it is through a PICC line not peripherally. Hope this helps.