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RespiraWorks / Ventilator

Fully-featured ICU ventilator design, optimized for manufacture using commonly available components and free to license. Repository tracks all mechanical, electrical and systems design, software, requirements and regulatory documentation.
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Add gas pipeline failure alarm #12

Open rwilbur opened 4 years ago

rwilbur commented 4 years ago

SR-19: Inlet Gas/Power Supply Failure

SR-24: Alarm shall trigger when O2 disconnection occurs

tapemaster commented 4 years ago

Slack thread related to this: https://respiraworks.slack.com/archives/C0100AC23MJ/p1590544077112700

dtgerson commented 4 years ago

For O2 low pressure or O2 disconnects:

Current idea: if we are maxing out the PSOL (commanding it to its highest state) but not able to control patient pressure (can't hit pressure target) or achieve the FiO2 level within the desired tolerance, then we know something is wrong with the oxygen (either disconnect or low pressure). So look for sustained deviations from the control set points (both the intra-cycle and the inter-cycles ones) Note: in parallel, we want to supplement with air - but we should still trigger an oxygen alarm.

For problems with the blower (not a gas supply but related):

Similar: if maxing out the air inhale valve but can't hit the target pressures, then something is wrong

tapemaster commented 4 years ago

Another discussion on slack here: https://respiraworks.slack.com/archives/C013KQQ18T1/p1590870727028600

jkff commented 4 years ago

I think there's been some indication that this may be overlapping with https://github.com/RespiraWorks/VentilatorSoftware/issues/368 - Like, having a "low pressure" alarm can be enough to detect disconnection?

Source: these notes - "Alarms: disconnect/low Pressure alarm (usually the same alarm"

dtgerson commented 4 years ago

I think there are related but slightly different things.

If you have a low FiO2 and you can't hit pressure - then it means something is going wrong, but it is not an issue with the O2 system.

If you have a high FiO2 and you can't hit pressure, but if you compensate with air and are able to hit pressure, then it says that there is something specifically wrong with the O2 system (likely the supply - though could be a failure of the vent/valve).

Unclear to me if we actually want to have two separate alarms for this or just have an alarm of "can't hit pressure" and then let the doctor figure out what is causing it. If we are going to build in logic that compensates with air if we can't hit the pressure at the desired FiO2, then it makes sense to have two alarms (one in general, one for oxygen specifically) - but I don't know if we've decided to add that complexity yet.

Does that make sense?