Dehydration

Just to make sure: There is no value provided by the engine describing current “dehydration”, right? (Stated here: Energy Methodology Future Works).

We just merged in a Dehydration model into the Integration branch
You specify it as a condition

We should get the documentation updated on our website soon

Test it out and let us know what you think!

Any idea when it will be available in the Unreal Plugin? I remember building the Pulse DLL on my side wasn’t that convenient.

Do you know if there is any way to get the expected intracellular fluid volume for a patient that is healthy in comparison to the actual intracellular fluid? I try to simulate the skin tugor on the backside of the hand. I suppose the skin tugor would be lower if the intracellular fluid decreased during dehydration but might increase in cases of hypotonic dehydration.

Next release if probably going to be this summer

I can build the contents of this folder for Win64 for you to test out. There may be a few interface calls that need to change, but I would not think it too bad… you would also need to update any states you are using… I can provide the default states too…

Are you using custom states?

I would appreciate the build and the default states. We start using custom states in the near future.

Any idea about the intracellular fluid? Otherwise I would calculate the expected intracellular fluid myself and compare it to the actual value.

What kind of Dehydration does the condition simulate? Isotonic, hypertonic or hypotonic? Or is it “simply” a check of how much of the total fluid mass is lost?

The new dehydration condition models nearly isotonic dehydration, typically resulting from excessive sweating.

The documentation has been updated, just not pushed to the website yet. You can see some details if you search for “dehydration” in the Tissue and Energy Markdown files. Table 6 in the Tissue Methodology has the latest validation results for the standard patient initialized with varying severities of the dehydration condition.

There are outputs for extracellular, extravascular, intracellular, and total fluid volumes in the Tissue System (see the proto file for the full list).

Awesome, thank you for the links to the upcoming documentation.

The intracellular and total fluid volume are the current volumes (in case of dehydration the reduced volume), right? Are there any public parameters to get the expected values for healthy patients without any conditions applied, to compare them to the current values.

Thank you (and @abray ) for the detailed responses. Using the severity alone would help to simulate the skin turgor. Looking forward to the release.

Yes, all of those volume outputs are recalculated every time-step, so they will change when dehydration is applied.

The latest healthy standard male results will be included in the automated validation that gets inserted into the documentation. This is the latest that is generated from the integration branch:

Will the base TotalFluidVolume be part of the patient state, that I can define in custom states?

No, TotalFluidVolume is not part of the patient baseline parameters. It is the sum of several compartments that are initialized based on other patient parameters. The code could be updated to distribute an explicitly defined volume, but it’s not currently implemented.

Thanks for clarifying that. The dehydration severity will be very useful to us. You are doing amazing work!

I appreciate you taking your time to answer so detailed. Have a great day.