Oscillation in vital signs after infusion

Pulse Physiology Engine
1

Hi,

I’m trying to simulate propofol infusion. I did nothing in the first 10 minutes just for comparison. Then, I followed this infusion scheme:

  • 100mL/min for 2 ug/mL for 15 minutes
  • 100mL/min for 5 ug/mL for 15 minutes
  • 100mL/min for 2 ug/mL for 15 minutes

I noticed that there are quite a few oscillation in the plots of the vital signs. I wonder if that’s normal, or I made a mistake? Thank you very much!

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Many thanks

2

Hello,

You are seeing some oscillations there. You are zoomed in pretty closely on the plots and those oscillations are 1-2 mmHg or 1-2 beats/min, which is fairly minimal for a dynamic simulation with the fluid volume changing in real time with the simulation. I think that is an expected and acceptable variation over time.

Thanks,
Rachel Clipp

3

Thank you so much! It’s good to hear that’s normal.

By the way, may I ask if it is possible to simulate a target controlled infusion (TCI) pump in Pulse Physiology Engine?

Many thanks
Shawn

4

Hi Shawn,

We do not currently have one modeled. I would need to think about how to do that. If I remember correctly, you enter the patient information (height, weight, etc) then the pump has an internal mechanism to calculate the drug dose to attempt to achieve a plasma concentration, is that correct?

You could certainly write a control algorithm if you have an equation to cut off the infusion based on that dose. You could also write an algorithm to control the infusion by slowing or stopping the infusion based on the plasma concentration as calculated by Pulse.

Sorry that is probably not as helpful as you were hoping.

Thanks,
Rachel

5

Thanks for your reply! I can think about if I can use a control algorithm.

Many thanks,
Shawn