Dear forum users,
We are currently working on a university project and we want to test the preset HowTo SESubstanceBolus on a sepsis patient. The problem we have each time is, that inherently, as expected, a sick patient cannot be initialized before running the simulation.
This has also been said on the methodology page for patients which possess normal values: “While every effort has been made to allow any combination of patient parameters within bounds, there is no guarantee that all combinations will be able to reach a stable starting homeostatic point.”
We manually tried to manually change the parameters after the initialization but this produced nonsensical results after running the SESubsanceBolus file (f.e. diastolic BP of 40 mmHg). Is there any way to work around it? Or is it advised to use another Physiology simulator since it is impossible?
So what we tried is: create a custom patient JSON with some values associated with sepsis (so no sepsis scenario has been run on the patient). F.e. a MAP of <60 mmHg. Initialize the patient and then give the fluid bolus to see how the vitals recover. But the problem is we cannot initialize a sepsis patient because it is intrinsically impossible to be a homeostatic state. Is there any way to work around this?
Ok, I think we misunderstand eachother? Because we are working with actual patient data from sepsis patients. We want to validate fluid administration with PyPulse. But it will be impossible since the patient has to be healthy before the actual simulation could run.
For the record: we are not working with any explorer; we are using the core engine code from Github. We built with CMake first and then ‘converted’ to Python. I’m not native English speaker so if there’s mistakes thats why.
Pulse always has to start with a healthy patient parameters (height weight sex etc.)
We use that information to configure our circuit models to simulate that healthy homeostatic state.
Once you have a healthy patient, you apply actions to Pulse to modify the physiology to represent some kind of trauma or illness. (Think of conditions as actions that are immediately applied to a healthy patient) More details can be found here
You need to get Pulse into your desired insulted/sick state in the most realistic way possible from a healthy patient for your interventions to mean what you want them to mean. How would a real person get to the physiologic state you desire?
For example, to explore various algorithms dealing with fluid resuscitation to recover a patient from cardiovascular shock; you first have to bleed a healthy patient to the point of cardiovascular shock, then resituate them.
Start Pulse with an SEPatient definition of a healthy patient
Apply an SEHemorrhage action to bleed the patient over time to something like a 40% blood loss, this will lower the MAP. You could vary your hemorrhage severity to get there faster or slower.
Use the SerializeToFile method on the engine to save the state of the engine at that point.
Write several methods that start the engine with that state file and perform an action that represents a resuscitation procedure, such as different types and flows of IV Fluids, and generate your data.
In the case of experimenting with algorithms to manage a septic state, our model is incomplete so I am not sure how to get Pulse into a septic state that also responds to treatment appropriately. You can experiment with the previously mentioned cardiovascular/respiratory modification actions to get Pulse to your desired septic state (Number 2 in the above sequence). But lowing arterial pressure using those actions will simply lower the systemic vascular resistance not the blood volume… so applying fluids may not work as expected…So if you are set on a sepsis study, Pulse if probably not ready yet for that use case. Are there any other use cases that you could study?