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A project log for COSV - Cam Open Source Ventilator

Roller cam based portable BVM ventilator.

daren-schwenkeDaren Schwenke 09/14/2020 at 20:490 Comments

#DP Ventilator just made it to the finals of Hackaday prize without solving *any* of the core requirements of this type of ventilator beyond squeezing the bag.

Uses one sensor.. so they can't detect if the hose is kinked, if a nurse turned on a peep valve, or if the patient is even still connected.  This *will* do the wrong thing in every one of those situations and harm the patient.

It is also impossible to implement any proper ventilation modes like that. If you implement pressure-based control you need to have flow as an output. If you implement flow-based control you need to have pressure as an output.  Otherwise you simply can't do the right thing, again harming the patient.

Uses a long hose between the ventilator and the patient guaranteed to build up CO2.  The valve and sensor stack needs to be connected at the patient or you never empty that hose.  The patient ends up breathing in 20% of the air they just breathed out over and over. You think wearing a mask is bad...

Uses the sensing idea of barometric pressure sensors, poorly, we submitted back in February to HelpfulEngineering during the initial massive sensor shortage, with no credit.  It is possible they ended up here though without ever seeing that.  Probably likely actually given they missed so much of the mark.

Is mechanically complicated and is much more likely to bind and fail with sliding elements.  We designed ours per the UK ventilator specification of surviving for a half a million cycles over two weeks.  

Is unable to actually meet the UK ventilator specification of an inhale cycle time of 0.3 seconds at 15cm/H2O.  We started completely over so we could.

This makes me sad.

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