# Pulse engine error after running mechanical ventilation over two days

**URL:** https://discourse.kitware.com/t/pulse-engine-error-after-running-mechanical-ventilation-over-two-days/1557
**Category:** Pulse Physiology Engine
**Created:** [September 8, 2025, 5:46am UTC](https://discourse.kitware.com/t/pulse-engine-error-after-running-mechanical-ventilation-over-two-days/1557 "2025-09-08T05:46:23Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![di.sheng](https://discourse.kitware.com/letter_avatar_proxy/v4/letter/d/9e8a1a/32.png) [@di.sheng](https://discourse.kitware.com/u/di.sheng)
#### Post date: [September 8, 2025, 5:46am UTC](https://discourse.kitware.com/t/pulse-engine-error-after-running-mechanical-ventilation-over-two-days/1557/1 "2025-09-08T05:46:23Z")

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Hi,

I use the pulse engine to run the mechanical ventilation with patient age/weight/height and feed with real time flow/pressure data, however after two nights of running the engine, there are engine erorrs":

[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Nitrogen  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Oxygen  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : CarbonDioxide  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Sodium  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Sodium  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Chloride  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Potassium  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Calcium  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Lactate  
[ERROR] [111949(s)] Compartment : SkinTissueExtracellular, Substance : Urea

then the mechanic ventilation keeps failing.

Process Action failed Conscious Respiration  
Process Action failed Mechanical Ventilation

Do you know what might went wrong? Thank you so much.

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### Author: ![abray](https://discourse.kitware.com/user_avatar/discourse.kitware.com/abray/32/12_2.png) [@abray](https://discourse.kitware.com/u/abray)
#### Post date: [September 9, 2025, 1:33pm UTC](https://discourse.kitware.com/t/pulse-engine-error-after-running-mechanical-ventilation-over-two-days/1557/2 "2025-09-09T13:33:20Z")

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Hi @di.sheng

Pulse simulations are only really valid for 8-12 hour runs. We don’t have a sleep model needed for simulating physiology for any longer running simulations. Something appears to be happening associated with substance consumption/production/clearing in such a long running simulation, but that is something that we currently do not support.

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### Author: ![di.sheng](https://discourse.kitware.com/letter_avatar_proxy/v4/letter/d/9e8a1a/32.png) [@di.sheng](https://discourse.kitware.com/u/di.sheng)
#### Post date: [September 9, 2025, 2:25pm UTC](https://discourse.kitware.com/t/pulse-engine-error-after-running-mechanical-ventilation-over-two-days/1557/3 "2025-09-09T14:25:47Z")

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Hi @abray ,

Thank you for your reply.