Altering medication dosage has no effect in Unity

Pulse Physiology Engine
#1

Hi all,

I’ve working with some of the medications in Unity and I’m not seeing any differences when I administer medications at different dosages, rates of administration or when I change the method of administration. I’ve tried all kinds of combinations but I’m not seeing any notable differences.

In particular, I’ve been working with Succinylcholine, Rocuronium, Propofol and Epinephrine. For example, when administering epinephrine as substance bolus or via substance infusion heart rate increases by about 26% regardless of dosage concentration or rate. I’ve tried a wide range of values and I still see identical physiological response each time.

I’ve expanded the PulseActionOnClick class a bit to fit our needs. To create new actions for the drugs that weren’t initially exposed I used the entries for Succinylcholine and Morphine as templates and alter the dosage parameters there.

I’m using Unity 2019.3.14f1

Best,
Mac

#2

I will take a look at the drug doses.

Step 1 is to take a look at plasma concentration abs make sure that is changing with dosage.

Step 2 is to then look at the effects. My guess is that the effects curve is too narrow and we need to correct it for a larger range of doses.

Sedation effect is usually a good to look at and see the effect change per dose.

Feel free to send the range of dosage and specific drug or two and I will take a look.

I should be able to check it and give you more feedback by Monday.

Rachel

1 Like
#3

Thank you for looking into this!

Epinephrine and Propofol are two of the ones we’re focusing on right now. As for ranges, maybe something like:

  • Epinephrine (0.1-5mg/10 cc)
  • Propofol (10-100 mg/10 cc)
#4

Hi,

What volume are you giving for those concentrations? How many cc or ml?

Thanks,
Rachel

#5

I’m sorry, I didn’t notice this. I’m actually not having issues with Propofol anymore. Epinephrine seems to be the main culprit. I’ve tried a range of dosages but the last test I ran administered it via substance bolus with these values:

  • Epinephrine concentration = 100 mg/mL
  • Epinephrine dosage = 10 unit/mL

It’s worth noting that changing concentration to something like .1 mg/mL results in the same physiological response as 100 mg/mL.

#6

Hello!

Just wanted to touch base here again.

Best,
Mac

#7

Hello,

So sorry for the delay. I think the dose you are giving is higher than we have ever tested. I tested with a 10ug dose. It looks like you are giving a several orders of magnitude larger dose? We do not have an overdose model at this time, so once you have maxed out the effect, it will appear the same. Epinephrine seems to be working in our system for a graduated response at the much much lower dosages.

I hope that helps.
Thanks,
Rachel

#8

Check out these scenarios to see what dose we are using for each drug to get a feel of what is a ‘normal’ application

https://gitlab.kitware.com/physiology/engine/-/tree/master/data/human/adult/scenarios/drug

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