Changing the Engine Parameter Group

Good day to all,

Advance sorry for my English, I hope that you will understand my questions.

We want to change the following group of engine parameters: heart rate, respiration rate (RR), SpO2 (concentration of oxyhemoglobin in arterial blood), but there must be a correlation between these parameters, i.e. If we change the heart rate, then the respiration rate should also give a reaction. The heart rate is almost adequately controlled, but the respiration rate does not respond to our manipulations. We want the patient's RR to rise from 16 to 30 and stay at that level. Tried to include the following compartments of the respiratory system and to change the pressure and resistance values in the nodes and paths: Ambient, Mouth, Carina, Left (Right) Dead Space, Left (Right) Alveoli + from the cardiovascular system included the following: Right (Left) Pulmonary Arteries, Capillaries , Veins.But the engine for a short time catches events such as respiratory alkalosis, hypoxia and quickly out of them. What else have we not considered?
Through which nodes can adequately control the concentrations of O2 and CO2? We tried various combinations of electrical schemes of cardiovascular and respiratory systems, but did not get the desired result. Can still some need to include compartments and systems in the work of the engine?

I hope for help in this exciting issue.


  • coolwebbcoolwebb Entry Level
    edited September 2017
    [Deleted by moderator due to violating posting rules]
  • Very grateful for the detailed response.
    The final goal is that we want to get a physiological engine, which already exists, on the one hand, and on the other hand, that the parameters in the engine change during the simulation. For example, when we change a patient's physiological parameter, the system should react to this. In our case, these parameters are the respiratory rate, heart rate, blood pressure, and the concentration of oxyhemoglobin in the arterial blood.
    Yes, we are going the approach you wrote about, i.e. we change the elements of the circuit. You said that you could offer specific elements of the scheme, with which you can achieve the desired result. Can you find out which elements are responsible for this? Because we have tried many options for changing the values in the nodes and paths of the electrical circuits of the cardiovascular and respiratory systems, but did not get what they wanted.
  • coolwebbcoolwebb Entry Level
    edited September 2017
    [Deleted by moderator due to violating posting rules]
  • coolwebb,

    Speaking about the correctness of the interpretation, then you have rightly noticed we want to realize such a thing. Besides this, it is important for us to know: is it possible to act at all on the heart rate through the nodes of the circuit, and so that the respiration rate? In addition, we need to get the response of the system when we change the parameters. In short, we need the correlation of these parameters and as far as possible to control it through the compartments of electrical circuits (nodes, paths).
    Thanks for the advice on using the events, it gave us the result, but not exactly, the one we expect, i.e. the parameters change, but the system still recovers quickly, and if we try to keep the event, the patient dies.
    Therefore, the main issue and goal for us is to assess the realism of what we want to do with the engine, using only control through the nodes.
  • abairdabaird Moderator
    Hi Evolve,

    coolwebb has given great answers to this question so far but I just wanted to chime in briefly and note that for the heart specifically a variable compliance element is the driver of the heart rate (cardiac cycle). You can change this parameter within the circuit by altering the compliance element manually. This is similarly done in the respiratory system, with the compliance of the left and right plural space. For the O2 and Co2 this becomes a bit harder because these levels are what drive a lot of the feedback mechanism that are modeled in BioGears (like coolWeb mentioned) so changing these things will result in downstream affects. You can also choose to change a patients respiration rate and baseline heart rate in the patient file you load in, or in code (for example like 1060 in respiratory.cpp you can just add a number to the baseline that is pulled in from loading the .xml patient file). It may also be advantageous to get in contact with some of the manikin developers who are integrating BioGears to see how they handle insults and interventions on a physical platform (if that is what you are interested in).

    I will say that we have future development plans to develop a better "parameter override" functionality that will be able to drive to and hold desired patient parameters, like heart rate, respiration rate, metabolic energy consumption..., and turn off the interfering feedback mechanisms that will fight you on it.

    We also have community outreach support, so if you'd like more detailed help always feel free to contact me with your issues and we can try and figure them out!

    Austin Baird
    BioGears PI

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