Hi #medtwitter !
This is a screenshot from Harrison of the management of DKA.
I want you to look at just the fluid management part.
Why is it recommended that we give so many different types of fluids?
A short 🧵on why we do what we do!
This is a screenshot from Harrison of the management of DKA.
I want you to look at just the fluid management part.
Why is it recommended that we give so many different types of fluids?
A short 🧵on why we do what we do!
In DKA, the plasma is severely hypertonic because of
1. High sugars
2. Ketones - especially beta hydroxybutyrate.
Hypertonic plasma = bad because water will be pulled from intracellular spaces.
This happens to your cells ⤵️
1. High sugars
2. Ketones - especially beta hydroxybutyrate.
Hypertonic plasma = bad because water will be pulled from intracellular spaces.
This happens to your cells ⤵️
Normal plasma osmolarity is 275-295 mmol/L
In DKA, usually its about 320 mmol/L
(In HHS its >320 mmol/L)
If you want to calculate plasma osmolarity, you can use the formula -
2 (Na + K) + BUN/3 + glucose/18.
In DKA, usually its about 320 mmol/L
(In HHS its >320 mmol/L)
If you want to calculate plasma osmolarity, you can use the formula -
2 (Na + K) + BUN/3 + glucose/18.
So you have hyperosmolar plasma and you want to reduce the osmolarity. What do you do?
You mix it with some fluid that has comparatively lower osmolarity.
But which fluids are hypo-osmolar?
You mix it with some fluid that has comparatively lower osmolarity.
But which fluids are hypo-osmolar?
Since DKA is hypertonic, most fluids have lower osmolarity in comparison.
We are interested in the green and blue fluids.
0.9 % NS and Lactated Ringer’s solution (LR) are isotonic (same as NORMAL plasma).
0.45% NS and D5% are hypotonic.
We are interested in the green and blue fluids.
0.9 % NS and Lactated Ringer’s solution (LR) are isotonic (same as NORMAL plasma).
0.45% NS and D5% are hypotonic.
Okay so we have all our players. Now we play the game.
When you have a very high plasma osmolarity, you can’t correct it rapidly.
If you did, you would cause the fluid to be pushed back into the cells rapidly and that’s never good.
Cell ⤵️
When you have a very high plasma osmolarity, you can’t correct it rapidly.
If you did, you would cause the fluid to be pushed back into the cells rapidly and that’s never good.
Cell ⤵️
So initially you pick a fluid that is close to isotonic.
First fluid is NS or RL (LR) ✅
First fluid is NS or RL (LR) ✅
Once you’ve given about 2 liters of isotonic fluids, your plasma osmolarity has probably come down a fair amount.
Now you want to use a fluid that is even more hypotonic.
So you give .45% NS. ✅
Now you want to use a fluid that is even more hypotonic.
So you give .45% NS. ✅
Now Harrison says, after giving NS/RL and then .45% NS, you can switch to D5% once the sugars are <250mg/dl.
Wasn’t the whole point of DKA to reduce sugars?
But Harrison says, we’re supposed to give 5% dextrose?
What gives?
Wasn’t the whole point of DKA to reduce sugars?
But Harrison says, we’re supposed to give 5% dextrose?
What gives?
Giving D5W (5% dextrose) has less to do with osmolarity and more to do with Na levels.
In DKA, as the renal threshold of glucose is passed, there is glucosuria.
Glucose loss = water loss.
But our body does a fantastic job of re absorbing Na.
⬆️ Na + ⬇️H2O = HYPERnatremia
In DKA, as the renal threshold of glucose is passed, there is glucosuria.
Glucose loss = water loss.
But our body does a fantastic job of re absorbing Na.
⬆️ Na + ⬇️H2O = HYPERnatremia
In the initial periods of correcting DKA, we are more concerned about correcting the osmolarity and the sugar levels.
So using NS / RL / 0.45% NS is okay.
As sugars are better controlled (<250 mg/dl), it is important to maintain Na levels.
So we give D5W which has 0 Na.
So using NS / RL / 0.45% NS is okay.
As sugars are better controlled (<250 mg/dl), it is important to maintain Na levels.
So we give D5W which has 0 Na.
So that is the basic idea behind giving multiple fluids in DKA.
Hope it helps and hope it made sense!
Hope it helps and hope it made sense!
@nihardesai7 @PanktiMehta24 @AdiG1993 @DrAditya2935 @MrPhysician2011 @DoctorBhavsar @karthik2k2
Would love any input!
Would love any input!
@jithin_mthw23 …Ketogenesis is minimal.
So yes D5 can help in the Mx of DKA in many ways
1. Keeps Na at bay.
2. Ensures adequate insulin levels to prevent ketogenesis
(2/2)
So yes D5 can help in the Mx of DKA in many ways
1. Keeps Na at bay.
2. Ensures adequate insulin levels to prevent ketogenesis
(2/2)
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