Choose Wisely… IVF Therapy & the Critically-Ill Patient

Dr. Michael Winters returns to discuss IV Fluid resuscitation in the critically ill patient.  Should we abandon Normal Saline? What other options are available?  What is a balanced fluid, and which patient might benefit from a fluid with a lower SID? Learn the answers, and become an expert in one of the most common therapies given in the ICU by watching this fabulous review by Dr. Winters.

Pearls

  1. Myth: It takes approximately 3x as much crystalloid when compared to colloid to achieve the same amount of intravascular volume expansion in IVF resuscitation.  Fact:  In the critically-ill patient, there is a degradation of endothelial glycocalyx lining the vascular system reducing the ratio to as low as 1.3:1.  
  2. The pH of a IVF does not determine the effect on the patient’s acid-base status.  What does?
    • Strong ion difference
    • Weak acid content (albumin, phosphate)
  3. The ideal balanced solution has a SID of about 24 (roughly equal to a normal bicarbonate level)
  4. Lactated ringers contains about 130 mEq of sodium, so avoid giving LR to patients with:
    • Traumatic brain injury
    • Hyponatremia
    • Cerebral edema
  5. It is recommended that patients diagnosed with SBP should receive albumin (1.5 g/kg of 25% solution) within 6 hours of diagnosis.

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Comments

  1. Alex K

    How much do the miscellaneous electrolytes in the balanced solutions matter (K, Ca, etc.). in other words, should I be nervous in ESRD patients, whose ability to manage electrolytes is off? Or are the concentrations inconsequential?

    1. MarylandCCProject

      Thanks Alex, here is Dr. Winters’ reply —
      ” Regarding the additional electrolytes in balanced solutions, manufacturers put these in order to make them as close to plasma as possible. In the end, I don’t think they have much clinical significance at all. Notwithstanding, I probably would avoid solutions with K for the ESRD patient presenting with hyperkalemia.”

      I’d agree to avoid IVF with K in patients who can’t eliminate their own potassium, but in my experience I haven’t seen a dramatic rise in potassium if the renal function is adequate.

      1. Megan Anders

        It’s interesting to consider:
        the effect of 4mEq/L potassium in a bag of P-lyte
        versus
        the potential change in extracellular potassium level induced by acidosis induced by normal saline bolus
        in the same ESRD patient needing 1L of crystalloid. Based on my experience resuscitating patients undergoing kidney transplants, I think we probably force more into acute dialysis territory with metabolic acidosis than with iatrogenic hyperkalemia from IVF…

        1. MarylandCCProject

          Great comments Megan! I think your anecdotal experience is interesting and probably right on. It just goes to show that we have a long ways to go until we’ve perfected our resuscitation strategies… Are you using a lot of NS in the OR for Resus?

          1. Megan Anders

            Essentially never… P-lyte has become my fluid of choice for all cases except acute neuro. In hospitals where P-lyte isn’t readily available, I’d use LR with the occasional bag of NS thrown in the mix to keep the Na closer to normal. I think we’ll be seeing more places start to stock P-lyte routinely (or, I hope!).

  2. Justin Sandall

    I think a lot of it depends on where the patient starts in terms of acid base status. In someone who is really acidotic, Plasmalyte/Normosol (SID of 50) or LR (SID of 28) are my choices for their alkalizing effect. If they have normal acid base, I like to go with LR since its SID is close to normal HCO3- it has the most pH neutral effect. If they are alkalotic (say from crap tons of emesis 2/2 a bowel obstruction) then NS (SID of 0) is a perfect choice, at least initially.

    In general (from Weingart’s site) “For the effects on a patient with altered pH, any fluid with a SID the same as the pt’s bicarb will keep the patient at the same pH. If the SID is greater than the pt’s bicarb, then the fluid will be alkalotic and if less than the pt’s bicarb–acidotic.” Quick and dirty way to think about it.

    Neuro patients do change the Rx a little bit as we want to avoid hypotonicity and hyponatremia but I have no problems using Plasmalyte/Normosol in place of NS as they are isotonic to plasma.

    I probably utilize albumin more than I should. One of the overlooked things about albumin is its effect on acid base status – you get a triple whammy for acidosis as it is suspended in NS (SID of 0), increases Atot and may increase free H20 from its oncotic effects (theoretical, I’d guess more likely with the 25% than 5%).
    Same can be said for 3% NaCl w/o the Atot contribution.

    Fluids we give are a Rx and we need to think of them as such.

    Megan Anders is wicked smart.

    Great site.

  3. Michael

    What a fantastic lecture!

    1. When choosing a resuscitation fluid in a shock patient with an elevated lactate, is there concern that the lactate in LR will interfere with the monitoring of lactate clearance?

    2. When choosing a resuscitation fluid in a shock patient who may have shock liver, is there a clinically relevant concern that Lactate (in LR) or acetate & gluconate (in plasmalyte) may not be fully converted to bicarb?

    1. MarylandCCProject

      Hi Michael! Thanks for the great questions and for listening….

      1. Generally no, I’m not aware of any evidence that the included lactate in LR has any major clinical effects on the monitoring of lactate clearance.
      2. Great question — Resuscitating the patient with shock liver or chronic liver disease is a common challenge, but we use a large amount of LR/P-lyte in our resuscitations here at UMaryland especially in these patients. I don’t believe there is any real clinical problems that arise from using these fluids in our resus.

  4. Alex K

    My understanding is that it is not detrimental to have unmetabolized/slowly metabolized lactate, the result is that you do not convert to HCO3 and then CO2 to blow off -> essentially returning the SID to zero, nullifying any potential acid-base benefit compared to 0.9%.
    If correct, credit to emcrit lecture.
    If incorrect, due to my faulty understanding/interpretation.

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