Introduction 0
The origins of the myth0
Why the myth is wrong0
thought often cited as a cause of hyperkalemia in those with renal dysfunction, infusion of LR with approximately 4 mEq/L potassium should not cause hyperkalemia. Even if the entirety of such a patient's plasma space was replaced with LR, the K+ concentration would not exceed the concentration of potassium in LR (4 mEq/L).
Secondly, when one considers that the volume of distribution of potassium is greater than the extracellular fluid volume, it becomes clear that any infusion with a near-normal potassium concentration will have almost no effect on the serum potassium level. Consider, for example, a 70-kg man with a serum potassium concentration of 6 mEq/L and an extracellular fluid volume of 15 liters. Let's suppose that we infuse him with one liter of a solution containing 8 mEq/L potassium. His final serum potassium concentration will be a weighted average of 6 mEq/L multiplied by 15 liters and 8 mEq/L multiplied by 1 liter, which comes out to be 6.1 mEq/L. Thus, his potassium level only increases by 0.1 mEq/L, a barely measurable difference. Considering that potassium equilibrates between the intracellular and extracellular fluid spaces, its volume of distribution is much higher than the extracellular fluid volume and therefore the increase in potassium will be lower than 0.1 mEq/L (Huggins 1950; Winkler 1938). Therefore, although a fluid with twicethe potassium concentration of LR (8 mEq/L) could theoretically increase the serum potassium level, it would require a vast amount of such fluid to have any significant effect.0
Clinical evidence
What about Plasmalyte or Normosol?
Conclusions
0
Related links:
- Thanks to @nfkb, this post has been translated into French (please see his blog here). Greatly appreciated @nfkb! All efforts to expunge this myth are needed.
- Skeptical Scalpel (@Skepticscalpel) feels that social media deserves recognition by academia, and used this blog post as an example. See his comment and my response also below.
- Pulmcrit wee: The cutoff razor - April 15, 2024
- PulmCrit Blogitorial – Use of ECGs for management of (sub)massive PE - March 24, 2024
- PulmCrit Wee: Propofol induced eyelid opening apraxia – the struggle is real - March 20, 2024
What do you think about the recent SPLIT trial published in JAMA suggesting no difference in AKI between balanced solution vs Normal saline
Fantastic post. Will definitely incorporate into my practice and teach others.
Thank you!
Thanks so much for your blog post and encouragement. I've previously read your posts about academic credit for blogging, and certainly agree with you. One reason I started the blog was that I was working very hard on lectures, but a lecture to a small group of people has limited impact. If I put the same amount of effort into a blog, it may be read by thousands of people and is freely available online as a reference. Over time blogging hopefully will be better recognized as a legitimate academic activity. In the interim, I'm happy to be connecting with… Read more »
I enjoyed this post very much. You explained the situation succinctly. It always amazed me when I was teaching residents and students that they did not understand about total body potassium being all most entirely intracellular.
I recently blogged that social media activities deserved academic credit. I have written a follow-up citing your myth-busting post as a nice example of why. Here's a link to that post http://skepticalscalpel.blogspot.com/2014/10/lactated-ringers-and-hyperkalemia-blog.html.
Keep up the good work.
We generally run potassium separately (even with normal saline), so this was not a practice change for our nurses. I'm not aware of whether it's safe to add potassium to LR or Plasmalyte, although I imagine that it should be. When treating DKA, instead of switching to D5 1/2 NS, I like to run a combination of D10W and LR/Plasmalyte. For example, running D10W and LR both at 100 cc/hr, this produces the same effect as running "D5 1/2 LR." This is based on the British DKA guidelines. Running the LR and D10W separately can make it easier to independently… Read more »
This is a great read, and so thank you for posting this.
The problem I foresee is with my nursing colleagues and old habits dying hard. Particularly, the issue relating to potassium replacement will continue to see 0.9% saline used with 20-40mmol/L of KCl added to it, as that's what they've always done. Are you adding KCl to LR or Plasmalyte?
If so, how did you convince the nurses to change practice?
Furthermore, after the glucose levels have dropped to 250mg/dl, which glucose containing fluid are you switching to, as most are acidotic as is 0.9% saline?
Awesome, many thanks! I put a direct link to your blog above.
Hello, for french reading people I have tried to translate Josh's article here : http://www.nfkb0.com/2014/10/01/le-ringer-lactate-est-sur-en-cas-dhyperkaliemie-et-cest-mieux-que-le-sale/
feel free to ask me for corrections
What about the use of LR as a main fluid in septic shock resusitation? Doesn’t the resulting hyperlactatemia bias the lactate clearance goal directed therapy? Thanks for your insight
December 2015 Anesthesiology article on fluid resuscitation during septic shock shows that use of LR improves mortality over NS. Worth a read for the details.
Thabks for sharing
This blog post is vindicating. I am MICU resident, hoping to do my fellowship in ID-Critical care. I recently had a patient with hypekalemia and hypovolemia (HyperK was prolly from the severe AKI), who I treated with Ca gluconate initially, then GI solution and some kayexalate. I used LR for resuscitation as the pt has a NAGMA and I did not want to worsen it with NS. Renal recommended Sodium bicarb drip, which I did not want to continue due to the sodium load and the hypertonicity and the poor efficacy in hyperkalemia. I got schooled for using a potassium… Read more »
I thoroughly enjoyed reading this. Looking forward to more of your topics in the future! Also, just in case you need any more ammo for your argument: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4029282/
J. S. N, MD Thank you, I just got chewed, humiliated and yelled at by a senior critical care fellow for using Lactated ringers for treating hyperkalemia in renal failure. I wanted to explain myself but my senior colleague kept pressing that the nephrologist too is mad with me. I just sat quite and decide to research the topic further before stumbling upon this wonderful piece. I was trained to us plasmalytes or normosol almost exclusively. We usually resorted to LR when normosol was out. Our last resort was normal saline. I was told today that the patient’s potassium will… Read more »
Such a helpful article. Seems this dogma is based on a logical fallacy.
Wonderful post challenging this flawed practice!
If I may ask, since lactated ringers is safe to use in the setting of hyperkalemia, can this safety statement be applied to hyperkalemia in the setting of Crush Injury? It appears that it’s all over trauma literature avoiding LR at all cost. Thank you.
Was an answer provided to this question? Up To Date also says to never use K+ containing fluids in crush syndrome. Why has the trauma literarure not addressed/corrected this issue, or, is there really a valid physiological reason?
Hi thanks for this ..based on the above would you then say that RL is also preferable in Rhabdomyolysis and crush syndrome?
Does the same reasoning apply for Ringers in hypercalcemic pancreatitis?
Just re-reading this (a personal favorite article for teaching interns) as a night pharmacist just challenged my 30cc/kg LR sepsis bolus as having “too much potassium to give within the 1-hour bolus window”, since I was ordering 3L essentially.
Has anyone else ever come across an institutional policy that limits K infusion to “not more than 10mEq in an hr” … and apparently regardless of the dilution of the solution?
Here is a policy outlining this https://www.safetyandquality.gov.au/sites/default/files/migrated/tools_alfred.pdf
I think the main reason is phlebitis, but not sure how dilution etc.plays into this
This is common practice in Scotland as well., The reason seems to be phlebitis and pain during infusion but has spread to any patient receiving potassium through a central line as well.
Dear Dr. Farkas, First of all thank you for your information. Second, the trials you mention there had either as a primary outcome point a rise in creatinine level like in O’Maley trial which also was rapidly stopped I guess, or like in Khojavi’s trial you forgot to mention that venous thrombosis was an issue in LR group; Modis trial was hard to find by link provided to be honest. It is very important to mention is that those 2 trials I saw are largely about specific kidney transplant patients and also have very different outcome points as well as… Read more »
Great! Your reviews and topics covered are very well chosen
Sorry stumbled across this late: I assume the horrifically low pH as well as the SID of zero would further contribute to the acidosis and thus the outwardly shifting of potassium
This may have already been commented on
I am but a simple anesthesiologist with a possibly unhealthy hatred for normal saline outside of neurosurgery.
I literally gave grand rounds on renal physiology- dragged the whole department through the loop of henle magic school bus style. Honestly, I think it’s the first time most had thought about counter current multiplication since step 1, but if it improves choice of iv fluids it’s worth it.
I love this post and I send it to my residents anytime the subject of fluid selection in renal failure comes up.
There was an opinion piece in the CJASN “In defense of NS” recently that argued for the use of NS in oliguric patients with hyperkalemia based on the reasoning that they are highly dependent on distal delivery of sodium to promote kaliuresis. The authors argued that the effect of NS in delivering sodium distally in the nephron outweighs the intra -> extracellular shifts in potassium caused by the hyperchloremic acidosis. I was wondering if you thought there are merits to that argument?
I am also interested to hear your thoughts on this having read that recently!
Very informative discussion on this topic!
Thank you for sharing this.
I am a little confused with the “weighted average” stuff…Can you or anyone enlighten me on the steps to take to arrive at the final result of 6.1 mEq/L please?
Thanks in advance!
É matemática (90+8)/16 = 6,1
Love it