Chi Chu

nephrologist & descriptivist. #NSMC | epidemiology | clinical reasoning

[Chi Chu @cdchu]

@suenlw Can take it to the next level: make it replace "ehr" with "EHR"

[Dr Danny Bate @DannyBate4]

English gets its adjective endings -al and -ar (as in 'nasal' and 'lunar') from Latin -ālis and -āris.

These are really the same ending! Latin used the form -āris to avoid two Ls close together in a word.

Hence we find -ar in words with L in the root, like 'solar' and 'vulgar'.

[Chi Chu @cdchu]

@JohnRMontford @SegalMin @NephroGuy I see that perspective of unitlessness but it's a limiting view-the concept of units still makes perfect sense & is much more explanatory if broadened to be "g of _"

Esp helpful in conversions like K/Cr. The 0.113 mmol/g factor only cancels mmol or g of Cr not just any mmol…

[Chi Chu @cdchu]

@AlanYuNeph @JohnRMontford Exactly… even g/g does not cancel out. It’s g protein / g Cr

[Chi Chu @cdchu]

@eugelin06 @NavTangri @NephroNinja @eric_weinhandl @hswapnil @ADAlthousePhD Could consider adding stepwise (have eGFR in model, then add eGFR slope) and seeing if overall fit improves, and argue if eGFR slope adds prognostic info. But effect sizes would not be cleanly interpretable. Teasing each apart w/collinearity is a conceptual challenge too IMO☝️

[Chi Chu @cdchu]

@MatthiasDiebold @hswapnil How much other IVF is there? Citrate rate?
Would look at total ins/effluent flow—if there’s lots (300+ ml/h) of 0K ins (citrate, drips etc), then maybe 3.2 is the steady state K…
Same principle as running D5 to reduce “effective” dialysate Na for CRRT+hyponatremia
@galindozip

[Chi Chu @cdchu]

@NephroGuy @Yahyaraufahmad @kidney_boy Last step should be (if you want to BSA index) to multiply by 1.73 then divide by the person’s BSA

So if the BSA is 3.46 (roughly double), then CL is only 41*1.73/3.46 = 20 ml/min per 1.73m2

For 1.73m2 person with 41 ml/min GFR, the indexed = 41 ml/min/1.73m2 (as it should be)

[Chi Chu @cdchu]

@rabihmgeha @DxRxEdu 'triphasic' response with hypothalamic tract surgery/trauma comes to mind:
1) hypothalamic dysfunction ➡️ DI
2) pituitary degeneration & ADH release ➡️ SIADH
3) depletion of ADH stores ➡️ DI

https://t.co/Nh6I4ELYrQ
https://t.co/JKds8qjLAW

[Chi Chu @cdchu]

@Nephro_Sparks @ClementLeeMD @hswapnil @ssfarouk @PAWellingMD And also plug for superhero kidney physiology as a future #nephmadness region

[Chi Chu @cdchu]

@Nephro_Sparks @ClementLeeMD @hswapnil @ssfarouk @PAWellingMD Yes—the animals nicely represent extremes. There are always limits, but it is interesting to wonder why physiology has these limits (even/especially in animals that push them to the extreme)

[Chi Chu @cdchu]

@Nephro_Sparks @ClementLeeMD @hswapnil @ssfarouk @PAWellingMD Right I interpreted the question as making *pure* water—not just low osm, 0 osm. But does any animal do this?
(Although I think the need is not there. Even a freshwater fish has osms it needs to excrete)

[Chi Chu @cdchu]

@ClementLeeMD @Nephro_Sparks @hswapnil @ssfarouk there’s some misinterpretation of the question, by free water I think you mean water with 0 osmolality. “Free water” is a sort of theoretical/relative concept (we do excrete FW regularly)
See @PAWellingMD answer re: energy. Need to maintain huge gradients to make pure water

[Chi Chu @cdchu]

@SatyaPatelMD Do you mean meds that can ⬆️ Cr without GFR change (bactrim, dolutegravir etc)

Or meds that can ⬆️ Cr, truly reduce GFR, but without intrinsic injury? (ACE/ARB, SGLT2i)

IMO, rampant Cr criticism (albeit deserved) distracts from the reality that not all true GFR reduction is bad

[Chi Chu @cdchu]

@NephroMD @kdjhaveri @AlanYuNeph @purvasharma821 Also in this figure, there's a correction to clarify 13 meq/g is not the same as 2.5 mmol/mmol, they are thresholds from different sources (no citations). That was always a source of confusion with this algorithm...

[Chi Chu @cdchu]

@NavTangri @AdanZBecerra1 @MaartenvSmeden @IntJEpidemiol @ramspek @LucyTeece @Kym_Snell @Richard_D_Riley @GelovenNan Agree @NavTangri. & in very high risk where gross miscalibration occurs (50% vs 80% sounds like/is a big error), at least for KFRE, it's clinically obvious both are very near ESKD. Clinical decisions aren't really different & death is a consideration on top of KFRE either way.

[Chi Chu @cdchu]

@jaykoyner @NephRodby @lowgfrdoc @DrTomasGuerrero @hswapnil @kdjhaveri @edgarvlermamd @kidney_boy @AmandaDZeidman From Table 1 in the article: In-line CO2 removal with CVVH (considered "very low flow") - has been tried but not very effective. Can get CO-level Qb with ECMO (which is pretty much air/gas dialysis).

https://t.co/rJW3JOXceu

[Chi Chu @cdchu]

@NavTangri @Jwaitz @egottliebMD When diff isn't big, answer is likely in btwn (combined eqn).
I'm tempted to think in wide disagreement, the likely case is at least 1 is being thrown off by non-GFR factors, and truth isn't necessarily the middle. But hard to know, and middle still may be best guess on average.

[Chi Chu @cdchu]

@RahulM_MD Perhaps partly counteracted by Gibbs-Donnan effect, but I think mild hyponatremia is not uncommon on CRRT... @hswapnil
https://t.co/Z46sAViyHR

[Swapnil Hiremath @hswapnil.medsky.social @hswapnil]

@NephRodby @amolmpatel @DCharytan @kidney_boy @jaykoyner @edgarvlermamd nice - really useful review - relevant snippet below

We went down this rabbit hole few years ago while measuring dialysate sodium - https://t.co/5avv0GRH56 in @KIReports - make sure one uses the correct conversion factors if doing so!

[Chi Chu @cdchu]

@NephRodby Have spent so much time chasing literature on the “descending limb”. Despite how ubiquitous “falling off the Starling curve” is as a colloquialism in wards teaching. Still don’t have satisfactory answers… @JGAmatruda

[Chi Chu @cdchu]

@Jwaitz @Gabby_Brauner27 Creatinine is not great, but everything you said is true even if we had a perfect GFR test. I tend to think of ACEi/ARBs as negative GFR-tropes (definitely not "nephrotoxins"). Imagine if people labeled beta blockers cardiotoxins😬...but here we are.
#lowpowermode