Lactated Ringers And Normosol In Hyperkalemia

As an intensivist and anesthesiologist, I spend considerable time pondering the physiology and evidence for practices and questioning dogma rampant in the ICU/OR settings. I’ve heard one recurrent theme: the fear of using Lactated Ringers (LR) and Normosol in patients with renal impairment. Why? Because they both contain potassium (K+), and patients with renal impairment not only tend to be hyperkalemic and acidotic but have difficulty in clearing potassium.

LR and Normosol have 4 mEq/L and 5 mEq/L, respectively, of potassium. In the context of acidosis, H+/K+ channels exchange protons for potassium, thereby increasing serum potassium. Additionally, potassium equilibrates between the intracellular AND extracellular compartments (high volume of distribution). Therefore, you can’t just “add” the potassium from intravenous fluids to the patient’s baseline serum concentration.

In reality, infusing a solution with less potassium than the patient will actually DECREASE the serum concentration to that of the infused solution – couple this with the fact that LR and Normosol are both alkalinizing solutions. Thus, the acidosis is offset, shifting the H+/K+ ATPase channel back in the opposite direction (more potassium shifted intracellularly, thereby DECREASING serum concentration). Also, don’t forget that NS can potentially complicate matters with a superimposed non-anion gap, hyperchloremic metabolic ACIDOSIS due to the chloride load.

Finally, several prospective RCTs in renal transplantation looked at potassium changes with LR versus NS administration. Surprise! Patients who received NS had a greater increase in potassium and often a lower serum pH. Admittedly, the intraoperative administration of fluid is somewhat different than maintenance fluid/boluses, but it sure makes you feel reassured that LR is safe in patients with renal impairment.

Drop me a comment below with questions! 🙂

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  1. Is the reason that LR will reduce serum K level due to PH or ions moving from low concentration to higher. Hate to ask a dumb question but I keep seeing that when LR has 4 MeQ/L and serum K is 5 you will lower serum K

    • It’s the fact that balanced crystalloids like LR are more alkalinizing than normal saline. Therefore, because one avoids the significant chloride load inherent to NS, one doesn’t have to be as concerned about a non-anion gap metabolic acidosis. Probably doesn’t make a huge difference for small volumes of fluid.

      Let’s consider a hypothetical example – a patient with a serum potassium concentration of 5.5 mEq/L. If one were to run a continuous infusion of a fluid with a potassium of 4 mEq/L, not accounting for fluid shifts or potassium shifting/excretion, the 5.5 mEq/L would trend down towards the 4 mEq/L concentration due to dilution effects from the fluid administration.

  2. Thank you so much all these days I was thinking Ns is the best option and preferred less LR over Ns and this information has really helped me in choices I make.

  3. This is incredibly helpful. It makes me want to start using LR for aggressive resuscitation in my DKA’s. My attending tends to use NS. I feel like LR is very underused.

    • In the course of treating DKA, at some point, you’ll need to supplement some potassium anyways. Might as well not compound their anion gap metabolic acidosis with a non-anion gap acidosis too from liters of not-so-normal saline!

      • in DKA ringer lactate is not indicated as lactate gets converted into sugar and may worsen or at least complicate the treatment. the best and standard approach is to give normal saline and shift to 1/2 ns or 1/2 DNS at optimal times

        • There’s data showing the benefits of balanced crystalloid solutions (LR, PlasmaLyte, Normosol, etc.) versus normal saline in DKA (renal protection, faster solution of acidemia, etc.) PubMed IDs 33196806 , 35186583, 35018349, etc.

  4. Thanks for this post! As a nurse who follows you, your posts like this that relate to more than just critical care or OR really help me understand how the simple day to day treatments I’m administering on the floor work. Questions are the best way to learn anything in medicine, eye-roll or not ????


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