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There seems to be an association between the use of "normal" saline and acute kidney injury (when compared with other IV fluids).
Why would that be?
#medthread #medtwitter #tweetorial
There seems to be an association between the use of "normal" saline and acute kidney injury (when compared with other IV fluids).
Why would that be?
#medthread #medtwitter #tweetorial
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We need to first understand 2 things:
What is the difference between saline and other "balanced" crystalloid IV fluids?
What is the evidence that saline is associated with kidney injury?
We need to first understand 2 things:
What is the difference between saline and other "balanced" crystalloid IV fluids?What is the evidence that saline is associated with kidney injury?
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How is saline different from other "balanced" crystalloid IV fluids?
Saline has
levels of Na/Cl
Bc of this difference in composition, when used in large volumes salineserum Cl levels and causes a hyperchloremic metabolic acidosis
https://bit.ly/358PJah
How is saline different from other "balanced" crystalloid IV fluids?Saline haslevels of Na/ClBc of this difference in composition, when used in large volumes salineserum Cl levels and causes a hyperchloremic metabolic acidosis https://bit.ly/358PJah
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What is the evidence that saline is associated with renal injury?
There are several studies suggesting this association. Here's one
https://bit.ly/2ZG8wbZ
What is the evidence that saline is associated with renal injury?There are several studies suggesting this association. Here's one
https://bit.ly/2ZG8wbZ
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Because there is significantly more chloride in saline than other IV fluids, let's zoom in and see how that might affect the kidney
Infusing high chloride-containing fluids into dogs decreased renal perfusion and glomerular filtration rate (GFR).
https://bit.ly/36ei7cy
Because there is significantly more chloride in saline than other IV fluids, let's zoom in and see how that might affect the kidney
Infusing high chloride-containing fluids into dogs decreased renal perfusion and glomerular filtration rate (GFR).
https://bit.ly/36ei7cy
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Why would high serum chloride levels decrease renal blood flow and GFR?
The answer involves the macula densa.
Why would high serum chloride levels decrease renal blood flow and GFR? The answer involves the macula densa.
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To review:
Macula densa cells sense Na/Cl levels in the distal convoluted tubule (DCT)
In response to increased Na/Cl levels in the DCT the macula densa decreases renal blood flow and GFR by inducing renal afferent arteriole vasoconstriction
https://bit.ly/2Qdwzf7
To review:
Macula densa cells sense Na/Cl levels in the distal convoluted tubule (DCT) In response to increased Na/Cl levels in the DCT the macula densa decreases renal blood flow and GFR by inducing renal afferent arteriole vasoconstrictionhttps://bit.ly/2Qdwzf7
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Look how close the macula densa and renal afferent arteriole are to each other
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776136/
Look how close the macula densa and renal afferent arteriole are to each other
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776136/
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When exposed to high levels of Cl (and Na) the macula densa cells literally swell.
https://www.ncbi.nlm.nih.gov/pubmed/12060602
When exposed to high levels of Cl (and Na) the macula densa cells literally swell.
https://www.ncbi.nlm.nih.gov/pubmed/12060602
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Along with swelling the macula densa cells release ATP, signalling nearby afferent arterioles to constrict,
renal blood flow and GFR.
This process is called tubuloglomerular feedback, allowing the kidney to regulate its own perfusion
https://bit.ly/2ZGbzRs
Along with swelling the macula densa cells release ATP, signalling nearby afferent arterioles to constrict,
renal blood flow and GFR.This process is called tubuloglomerular feedback, allowing the kidney to regulate its own perfusion
https://bit.ly/2ZGbzRs
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ATP release from the macula densa cells is actually stimulated directly by Cl
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776136/
ATP release from the macula densa cells is actually stimulated directly by Cl
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776136/
So,Cl sensed by the macula dense leads toATP release, which signals afferent renal arterioles to constrict, whichGFR
Cl sensed by the macula dense leads toATP release, which signals afferent renal arterioles to constrict, whichGFR
12/
Let's summarize:
"Normal" saline haslevels of Cl compared w/ other IV crystalloid fluids
Increased serum Cl levelsrenal blood flow and GFR
This occurs because of ATP release from macula densa cells, which causes renal afferent arteriolar vasoconstriction
Let's summarize:
"Normal" saline haslevels of Cl compared w/ other IV crystalloid fluidsIncreased serum Cl levelsrenal blood flow and GFRThis occurs because of ATP release from macula densa cells, which causes renal afferent arteriolar vasoconstriction
