You've probably heard "don't give lactated ringers because it raises lactate"
This statement is ~98% false, but there's one crucial practice-changing fact that you need to know.
A š§µ all about lactic acid and lactated ringers!
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This statement is ~98% false, but there's one crucial practice-changing fact that you need to know.
A š§µ all about lactic acid and lactated ringers!
1/
First off, we should ackowledge the obvious: Lactated ringers does in fact contain lactate... 28 mEq/L in fact
BUT there's one little detail to remember:
Lactate ā Lactic acid
When we measure "lactate" we care about the ACID (H+) which lowers pH & causes organ dysfunction
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BUT there's one little detail to remember:
Lactate ā Lactic acid
When we measure "lactate" we care about the ACID (H+) which lowers pH & causes organ dysfunction
2/
But the correlation between pH & lactate is really bad!
Look at this analysis of lactate vs pH in 171 ICU patients.
There is a *weak* correlation in people with arterial lactate > 5, but even w/ lactate =10, pH ranged from 7.5 to 7.05. Quite a spread!
ncbi.nlm.nih.gov
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Look at this analysis of lactate vs pH in 171 ICU patients.
There is a *weak* correlation in people with arterial lactate > 5, but even w/ lactate =10, pH ranged from 7.5 to 7.05. Quite a spread!
ncbi.nlm.nih.gov
3/
Because lactated ringers contains lactate, it SHOULD raise lactate *a little*
If you gave me 1 L of LR, you'd expect my lactate to rise by... 0.5 mEq/L
Math:
85 kg x 0.6 (water fraction) = 50 L volume of distribution
28 mEq / 50 L = 0.56 mEq/L increase in lactate
But...
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If you gave me 1 L of LR, you'd expect my lactate to rise by... 0.5 mEq/L
Math:
85 kg x 0.6 (water fraction) = 50 L volume of distribution
28 mEq / 50 L = 0.56 mEq/L increase in lactate
But...
4/
Beware of labs drawn from an IV where LR infused!
LR can "contaminate" IVs leading to spurious venous lactate.
A study found that normally ven/art lactate were identical. If lactate was drawn from an IV that infused LR there was a BIG delta! up to 4x!
pubmed.ncbi.nlm.nih.gov
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LR can "contaminate" IVs leading to spurious venous lactate.
A study found that normally ven/art lactate were identical. If lactate was drawn from an IV that infused LR there was a BIG delta! up to 4x!
pubmed.ncbi.nlm.nih.gov
5/
I've seen this happen several times:
A seemingly stable patient has a lactate rechecked and it inexplicably "shot up!" leading to someone freaking out. š±
Turns out the lactate was drawn from a PIV where LR had just been infusing. The jump was just an artifact! Phew!š®āšØ
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A seemingly stable patient has a lactate rechecked and it inexplicably "shot up!" leading to someone freaking out. š±
Turns out the lactate was drawn from a PIV where LR had just been infusing. The jump was just an artifact! Phew!š®āšØ
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As a sidenote:
This is one reason why I like checking arterial lactate (assuming of course the person already has an art line) - there is no danger of a LR infusion "contaminating" the measurement.
BTW this is why the fluid used for art lines should always normal saline!
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This is one reason why I like checking arterial lactate (assuming of course the person already has an art line) - there is no danger of a LR infusion "contaminating" the measurement.
BTW this is why the fluid used for art lines should always normal saline!
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Should we even be checking serial lactates?š¤·
Elevated lactate IS associated with worse outcomes BUT it may not be a great resuscitation endpoint in sepsis. In fact, in one RCT lactate-guided resuscitation led to more fluid boluses & WORSE outcomes.
annalsofintensivecare.springeropen.com
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Elevated lactate IS associated with worse outcomes BUT it may not be a great resuscitation endpoint in sepsis. In fact, in one RCT lactate-guided resuscitation led to more fluid boluses & WORSE outcomes.
annalsofintensivecare.springeropen.com
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Summary:
-serum lactate does not correlate well with pH
-giving LR boluses can trivially raise serum lactate: ~0.5 mmol/L
-LR "contaminating" a IV catheter can cause a BIG jump in lactate! >5 mmol/L
-if you see a big jump in lactate, CHECK where it was drawn & avoid a freak out!
-serum lactate does not correlate well with pH
-giving LR boluses can trivially raise serum lactate: ~0.5 mmol/L
-LR "contaminating" a IV catheter can cause a BIG jump in lactate! >5 mmol/L
-if you see a big jump in lactate, CHECK where it was drawn & avoid a freak out!
Visual abstract:
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