Time & Time Again

This blog post is dedicated to the updates made in SimTIVA since start of the year 2024 up to April.

In my last blog post, I mentioned that SimTIVA simulations are based on 2 hour infusions by default. However, receiving multiple feedback from users (thank you!), this seems to be a major constraint clinically as anaesthetists may use SimTIVA to guide infusions lasting over 2 hours. I have changed the default infusion scheme data generation to cover 6 hours so as to maximize the convenience to the user. So, for every change in the infusion rate, or starting/changing of a target in CPT/CET scheme, the infusion data will cover 6 hours starting from the time of change. To clarify, this doesn't mean that SimTIVA program ends in 6 hours time, it merely means that starting from the last time you have started/changed the infusion rate or CPT/CET target, the data will last for 6 hours. To continue using SimTIVA before that time limit expires, simply enter another infusion rate or CPT/CET target, and data will be generated for another 6 hours. A "time's up" warning box will also appear if the infusion is nearing the end.

Another interesting feature is added. SimTIVA has introduced "Timeline Controls", namely:

  • Quick reset:
    Keep same patient data and start over from time zero
  • Pause sim:
    Suspend simulation and keep all data, this is analagous to pausing a video playback
  • Jump to time:
    Jump backward or forward in time, like skipping to different time point of a video


Note that these functions will separate the simulation from working in real time, but may be advantageous in several situations. For example, you may wish to partially go back in time and try different dosing regimens by testing different infusion rates, or the effect of different doses of boluses. Or, you may have forgotten to start SimTIVA 5 minutes ago after you started actual clinical case, but you may still enter the infusion data into SimTIVA and jump forward 5 minutes and that would align the SimTIVA timeline to current time instance.

Last but not least, another model is added to SimTIVA. It is "Eleveld model without opioids". This is for scenarios where propofol is used alone. From the Eleveld paper, opioids may result in age-related declines in V3 and clearance, and hence the model without opioid will result in higher infusion rates.

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