Load Environment in Pulse Explorer

Pulse Physiology Engine
#1

Hi there, I’m trying to see if I can get a patient to become hypothermic in the Pulse Explorer by simply changing the environment, but I’m having trouble getting any of my changes to stick. Here’s what I’ve tried:

  • Created a blank/default patient and loaded the AnchorageDecember environment as well as the SubmergedFreezing environment, however, when I start the engine, it seems that all the environment parameters get reset to the default
  • same as above but with a preloaded patient (Underweight)
  • starting the engine with a blank patient or preloaded patient, pausing the explorer, loading an environment file, clicking ‘apply all changes’ and then un-pausing the explorer - nothing seems to change

I’ve seen some post about how to change the environment in the Pulse code itself, but not in the explorer, what am I doing wrong?

Thank you!

#2

Hey Tyree,

I do not think I have hooked up setting the environment as a condition yet in the explorer.
But I believe that you can create your patient, start the engine, then load/apply your environment, and run the engine in real time (super fast) and that should brrr the patient.

Give that a go

#3

When I start the explorer, load the environment (SubmergedFreezing) and click ‘apply all changes’ the patients vitals remain stable :confused: also the ‘apply all changes’ button doesn’t grey out, which makes me think the changes were not actually applied…

#4

So if you follow the steps, you should see the action being processed in the log (like shown below)

image
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You can see the skin temperature has gone down, but the core temperature has not.
So the vitals will be pretty normal.
This is due to the Clothing Resistance value used in these environment files.
The patient is wearing the appropriate clothing for the environment we are putting them in,
You should probably manually set this to 0.5 clo after you load and before you apply the environment.

That way you are submerging the patient in freezing water with in appropriate clothing

#5

You probably should look at this scenario for a better list of values you should use in an environment to get hypothermic : https://gitlab.kitware.com/physiology/engine/-/blob/master/data/human/adult/scenarios/energyenvironment/ColdWaterSubmersion.json

And look at the plots of this scenario under the Cold Water Submersion section in the energy validation page : https://pulse.kitware.com/_energy_methodology.html

#6

Ah that makes sense, however, whenever I run the Pulse explorer, the ‘data requests’ tab is always blank, do I have to do something on my end to see that information?

#7

Have you got the latest explorer (or build the latest 2.x branch?)

Look at item 4 on the wiki
https://gitlab.kitware.com/physiology/explorer/-/wikis/home

#8

Yeah I’m pretty sure I have the latest version. When I download the cold water submersion scenario from the link above and load that into the explorer, I then can see things on the Data Requests tab

The scenario seems to work for causing hypothermia, so, thank you!

#9

Note, I have no doubt there are issues with the Explorer
So if you see anything weird, feel free to make an issue
Its still very much a work in progress…

#10

So while running the Cold Water Submerged scenario, it runs for about an hour and the patients internal temperature doesn’t go below 35.6 ish… I feel like the temperature change should be faster or at least more pronounced? Is this just an artifact of the amount of clothes they are wearing/the temperature of the water? Or is it a known issue that the temperature doesn’t change all that much…

#11

Additionally, in the code itself, the description says he is submerged for 5 minutes, but when I load the scenario it looks like he is submerged for 1 hour?
image

#12

Per the scenario,
The patient is in the water for about 3600.0s
Then taken out, and put in front of a heater
The body temp then slowly keeps lowering, stabilizing, and coming back up.
So you could keep him in the water longer or not heat

It does look like the plots are coming out wrong on the methodology page… I will need to look into that
The grey line Legend should be the yellow line…

I honestly am not sure how long this should all take…
But this scenario is validated with references…

#13

There is a known issue with the energy system that makes it extremely hard to achieve hypothermia (core temperature below 35 degrees C). It’s likely that the models for patient thermal regulation are too “good” at maintaining healthy values. As far as I know, there aren’t any near-term plans to update these models. One way to “hack” it quickly would be to reduce the metabolic rate in the energy system code. However, that parameter is not exposed through the API.

#14

Ah, that makes sense, good to know!

#15

Just to follow up on this – the comments in the scenario file (which indicate the patient are submerged for only 5 mins) are incorrect, right? I see the 3600s in there, too, so I assume the comments are just out of date.

#16

Yes, this description is wrong
It should be:
Patient is submerged in 10 C water for 1 hour. Removed for 10 minutes, and then actively heated for 20 minutes

But the other thing is that this image in the methodology report is also wrong

image
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The yellow line is actually the environment change
And the Orange line is the heating

The gray and pink lines should be events thrown by the engine… not actions

#17

FYI, the description in the table for the cold water submersion on this page is also wrong (it says it’s 5 deg C): https://pulse.kitware.com/_energy_methodology.html

#18

Thanks!

We will update this as part of the documentation for 3.1, coming soon!

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