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Johannes Enevoldsen @johsenevoldsen.bsky.social · 3d

"If CO increases, EtCO2 rises, CO2 elimination increases, PaCO2 falls and this is also sustained."

The problem here is that if CO2 elimination increases, without a matching increase in production, dissolved CO2 will drop with a constant rate (elimination - production)

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 3d

In ROSC, there is definitely an increase in CO2 production to maintain the new EtCO2.

I dont see how an increase in EtCO2 is not directly proportional to the amount of exhaled CO2 (unless the patient suddenly gets obstructive).

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 3d

So when people use/study EtCO2 as indicator of fluid responsiveness, they look for a *temporary* increase in EtCO2? This is the model that makes sense to me, but I could not find it specified in any of the papers.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 3d

CaCO2 refers to the average CO2 in blood (arterial + venosus), right? The arterial concentration increase with ⬆️CO.

VCO2 = Exhaled + ΔCavCO2

At steady state the dissolved part is constant, so VCO2 = exhaled CO2.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 4d

I see how better V/Q will get EtCO2 closer to PaCO2.

But how can we sustain a higher EtCO2, if production is constant?
Assuming a square capnography curve, EtCO2 must be directly proportional to the volume of exhaled CO2, which must equal the production of CO2 (at steady state).

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 4d

I don't understand the relationship between CO and ETCO2.

ETCO2 increases with rising CO, if ventilation and CO2 production is constant.

Is this just temporary?
We can't exhale more CO2 than we produce.

#anSky #medSky
@doctorhelgi.bsky.social
@load-dependent.bsky.social
@jm-l.bsky.social

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Reposted by Johannes Enevoldsen

Adam Kucharski @adamjkucharski.bsky.social · 19d

There's a puzzle I've found annoying so I thought I'd let you find it annoying too: kucharski.substack.com/p/why-the-tu...

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Johannes Enevoldsen @johsenevoldsen.bsky.social · 19d

I find it more acceptable if it's formulated as: You ask a person with two kids: "is at least one of your kids a boy born on a Tuesday?" They say "yes". What is the probability that they have two boys?

Johannes Enevoldsen @johsenevoldsen.bsky.social · Sep 29

Ah 👌 det giver jo egentligt god mening. TIL

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Sep 29

Ok. Mit eksempel var grammatisk forkert ☺️ " ... med dens krig"

Men er den oprindelige overskrift ikke stadig god nok?

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Sep 29

Er det ikke korrekt? "dansker banker" er grundled i sætningen.

Sætningen kunne forsættes "... med deres krig"

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Reposted by Johannes Enevoldsen

michielstock.bsky.social @michielstock.bsky.social · Jun 18

Small blog post on how to automate model building for mechanical systems using ModelingToolkit. #julialang

michielstock.github.io/posts/2025/p...

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Reposted by Johannes Enevoldsen

Trish Greenhalgh @trishgreenhalgh.bsky.social · Jun 19

Thanks for the reminder @janemunday.bsky.social. Every summer, I repost this article DROWNING DOES NOT LOOK LIKE DROWNING. To date, I know of FOUR kids who were saved after someone who'd clicked on the link learnt how to spot actual drowning. Take time to read and pass on.

slate.com/technology/2...

Drowning Doesn’t Look Like Drowning

Drowning is not the violent, splashing call for help that most people expect.

slate.com

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 18

Great ... though it would have been nice to make this show 0✅

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 18

I have the same problem. If I only ever intend putting it on GitHub, is it reasonable to just ignore it? Escaping all these characters will make the code a lot less readable.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 17

Thank you. With such praise, it is hard not to:
RSS: jenevoldsen.com/index.xml

jenevoldsen.com

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 13

It would be a reasonable regulatory mechanism, that lactate signals increased oxygen demand and raises CO, though I don't know whether it is possible, or even meaningful, to distinguish whether lactate is both fuel and a signal, or just fuel.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 13

Just found that the same group also did this study, showing that lactate increases CO in healthy adults. pubmed.ncbi.nlm.nih.gov/39825426/

Cardiovascular effects of lactate in healthy adults - PubMed

https://clinicaltrials.gov/ct2/show/NCT04710875 . Registered 1 December 2020.

pubmed.ncbi.nlm.nih.gov

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 13

bsky.app/profile/johs...

Johannes Enevoldsen @johsenevoldsen.bsky.social · May 26

My cardiac arrhythmia simulation now also simulates how a reentrant loop can be terminated by increasing refractory time as suggested by @empoisonpharmd.bsky.social

Direct link to the updated part:
jenevoldsen.com/posts/excita...

Reposted by Johannes Enevoldsen

Lars Mølgaard Saxhaug @load-dependent.bsky.social · Jun 13

Absolutely fascinating! We know the heart switches to lactate as energy substrate in shock, could there be a clinical benefit from lactate infusion in human cardiogenic shock? #emimcc #cccsky

BMC @bmc.springernature.com · Mar 20

Lactate infusion enhances cardiac output and peripheral perfusion in ischemic cardiogenic shock without affecting heart rate or systemic blood pressure, finds a study published in Critical Care.

#MedSky

Lactate infusion improves cardiac function in a porcine model of ischemic cardiogenic shock

Critical Care

bit.ly

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Johannes Enevoldsen @johsenevoldsen.bsky.social · Jun 13

Incredible effect sizes. Do we know what lactate does in a healthy heart? From a teleological perspective, it would make sense that lactate has a positive inotropic effect, regardless of it being a substrate. Simply as a signal of hypoperfusion.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · May 26

I'm sorry you had to experience that. Unfortunately I don't know what determines which treatment is tried first, or whether e.g. cardioversion can be expected to work if the condition reoccurs, when it didn't work the first time.

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Johannes Enevoldsen @johsenevoldsen.bsky.social · May 26

My cardiac arrhythmia simulation now also simulates how a reentrant loop can be terminated by increasing refractory time as suggested by @empoisonpharmd.bsky.social

Direct link to the updated part:
jenevoldsen.com/posts/excita...

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Reposted by Johannes Enevoldsen

Sam Rose @samwho.dev · May 8

✨ It's new samwho visual essay o'clock! ✨

Reservoir sampling is one of my favourite algorithms. It allows you to sample from a set without knowing the size of that set.

I try to assume no prior knowledge, and use no scary math notation. Just beautiful visuals.

Let me know what you think! ❤️

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Reposted by Johannes Enevoldsen

Ryan Feldman PharmD DABAT @empoisonpharmd.bsky.social · Apr 29

I just want to say I use this constantly at the bedside when dealing with patients who have arrythmias to explain how they propagate.

would LOVE LOVE a model where increasing refractory terminates reentrant rhythm so I can show how diltiazem terminates SVT.

such an amazing tool, thank you

Johannes Enevoldsen @johsenevoldsen.bsky.social · Feb 20

I wrote a short interactive article👆

It uses simulations to demonstrate how different cardiac arrhythmias can develop.

Try it out! (It has defibrillators ⚡️)

jenevoldsen.com/posts/excitable-cells

#medsky #cardiosky #cccsky #emimcc

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