hyperkalemia and balanced crystalloids


    hyperkalemia and balanced crystalloids

    Is it safe to give LR or plasmalyte to a hyperkalemic patient (these balanced crystalloids have 4-5 mEq/L K as opposed to 0 mEq/L K in normal saline)? Postponing the discussion of renal handling of potassium to review the physiology of fluid resuscitation in the setting of hyper K (per request by Dr Hickey). This has been debunked many times elsewhere, but here is my perspective as a chemist.

    Fluids are medications, and we can do harm by ignoring the tonicity. Balanced crystalloids distribute into the extracellular space because they are nearly isotonic to plasma:

    For resuscitation, we care about how much goes into plasma, which is only ~25%! So only 250 mL of a 1 L balanced crystalloid actually contributes to the intravascular space. Review why D5 (5% Dextrose) in water is not a resuscitative fluid. Here is a good table summarizing the compositions of fluids:

    We should NOT be worried about LR or plasmalyte increasing the [K+] in a hyperkalemic patient who requires fluid resuscitation.

    This is why:

    Basically, the contribution of the K from LR (i.e. 4 mEq total) to the extracellular space is relatively small. When the final K content is divided by the total extracellular volume, the [K+] actually decreases!

    Check out actual data (Panel D) from the SALT-ED trial:

    Even more interesting is Panel E… Why does the bicarbonate decrease with administration of saline? May have to postpone renal handling of potassium once again to review hyperchloremic acidosis, strong ion difference, and a new look at anion gap.

    • Welcome! This is the website for the Mount Sinai Emergency Ultrasound Division. It serves as an information resource for residents, fellows, medical students and others seeking information about point-of-care ultrasound. There is a lot ofRead more

    • renal handling of water

      If you were on a tea & toast diet, how much water would you need to drink before you develop hyponatremia? I haven’t seen anyone work out the numbers before so here are my calculations. AndRead more

    • acute acidemia physiology

      As alluded to in the first post, don’t be fooled by a “normal” potassium in the setting of DKA because osmotic diuresis and H+/K+ exchange means that total body potassium is actually LOW. You all knowRead more

    • renal handling of potassium

      the first symptom of hyperkalemia is death Earlier post covered temporizing measures to counter hyperkalemia — namely, intracellular shift, increasing cardiac myocyte threshold potential. Give furosemide if the patient still urinates and consider dialysis, but then askRead more

    • bicarbonate revisited

      Previous post reviewed the safety of balanced crystalloids in hyper K. But what was up with serum bicarbonate decreasing with saline administration? This post introduces a new way of looking at the anion gap to possiblyRead more

    • hyperkalemia physiology

      You’ll likely encounter hyperkalemia on your next Resus / Cardiac shift, and you’ll instinctively treat it. But take a moment to review the fascinating physiology behind the “cocktail”! First, consider how K+ is buffered byRead more

    • Slow down your tachycardia (but not really)

      You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate wasRead more

    • Otitis externa: use the ear wick!

      Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear”Read more

    • Reach for the COWS

      Your patient in intake is miserable. Doubled over, complaining of pain everywhere, sweating, ill-appearing but not unstable. He tells you that the last time he used heroin was two nights ago, and he is askingRead more