A Novel Mechanical Ventilator Designed for Mass Scale Production | Hacker News Reader

A Novel Mechanical Ventilator Designed for Mass Scale Production

arxiv.org

242 pointscozzyd135 comments

Why do we need more designs? We have designs. We need more production. If we need simpler designs, brush off the proven designs for 40 year old emergency field medicine ventilators and manufacture them. To paraphrase, designs are easy; manufacturing is hard. Stop tossing around unproven designs that are unlikely to roll off the assembly line any time in the next few months and focus on getting current manufacturers anything they need to scale existing production. It's not like there aren't simpler, emergency-ready rapid deployment models already on the market: use them! [0]

[0] http://www.alliedhpi.com/mcv.htm

Can my factory manufacture these designs?

I don't know anything about your factory. But if you mean, can they do it from the perspective of IP/proprietary data etc., then that's the bottleneck to solve. The DPA could easily cut through that bottleneck if existing factories could quickly be retooled to manufacture existing, proven & approved designs. The alternative is to retool to produce novel, unproven, unapproved designs. If you have a factory, great! You'll need to retool it though. Which design would you rather target? A simple, proven, approved design tailor made for this sort of situation? Or the simple, tailor made, but unproven new ones that are being thrown together in a few weeks?

"Which design would you rather target? A simple, proven, approved design tailor made for this sort of situation? Or the simple, tailor made, but unproven new ones that are being thrown together in a few weeks?"

Perhaps both paths will prove necessary and valued?

What capabilities does it have?

What capabilities does it need?

GP's point was why do we need new designs when company X already has a proven design. Well I can't access that design; it isn't published. My factory has cleanrooms, CNC tools, presses, waterjet cutters, testing equipment, and more, and a lot of flexibility and is presently running well below capacity. But I can't even assess whether that tooling is sufficient to make that design.

The open source designs do at least solve this problem.

Injection molding - The TOP thing we need to get mass manufacturing going. I just watched NYTimes front page video of Georgia Tech students trying to 3D print their way - it is unbelievably naive to use 3D printing in a situation that needs thousands and hundreds of thousands of parts. It defies common sense and elevates 3D printing to a new buzzwordy things by the media.

Do you have injection molding tools and mold making expertise?

While it is very obviously suboptimal, I don't see why 3D printing should be dismissed entirely in situations like the current one.

The point is that we have thousands of these 3d printing machines distributed around the world, with a good amount of source material. At this point, we can afford to brute-force our way to producing hundreds of thousands of items, don't we?

This is not going to solve all our manufacturing needs, not even by a long shot, but it seems it could fill very specific critical and unexpected needs.

It's an opportunity cost. If we allocate resources that can otherwise be put to a better use, why not? Efficiency is king in mass production.

By all means, use 3D printing at hospital level to get things made that's needed. A parts of the face shield (such as the head band) can be locally manufacturered using 3d printers.

But it is boggling to me that the media keeps wanting to get 3D printing buzzword clicks than actually asking manufacturing engineers.

3D printing becomes more viable as people use it. Right now it is pretty niche, but many groups are doing it on an industrial scale.

If every household or building had one, the parts could be crowdsourced from every machine that could make them.

The difference between where 3D printing and injection molding technology is right now is that 3D printers have scaled down in size and cost to the point of consumers being regular folks.

As for right now, 3D printing can help but it won’t be the savior of mankind.

Yet

Is there no such thing as a chain of custody for parts manufacturing? Crowd sourcing plastic parts from printers seems beyond naive. Do you know what goes into design of plastic molds or the repeatability and tolerances required? How do you quality control parts created from layers of hot glue? Plastic molded parts can rely on fundamental chemical understanding and tuned parameters of a molding machine.

> Well I can't access that design; it isn't published.

Apparently thats not true:

"I really don't get this DIY respirator hype. I get the idea, but why does everyone seem to reinvent the wheel using their "fancy" 3D printers and arduinos?!

This is 70s 80s tec, all patents expired. There are literally pages of exploded view drawings: http://www.frankshospitalworkshop.com/equipment/ventilators_...

Source: https://twitter.com/FauthNiklas/status/1242064388300947456

Patents and service manuals are not designs. They are just symbolic representations to illustrate the principles of operation. For manufacturing you need exact dimensions and tolerances for every part.

And the tolerance stackup is what makes it both expensive and reliable.

A whole lot of people are going to get a simple introduction into why some things are expensive.

Exactly. This is like handing someone a published API and asking why they can't just compile and run it.

Patents and service manuals are most of what you need to start reinventing the wheel. They're what you hand your R&D staff as you start reverse-engineering something, learning along the way all the little tricks that make it harder than it looks. They're not what you hand your machine shop and start producing.

From the second sentence of the abstract: "This ventilator is an electro-mechanical equivalent of the old, reliable Manley Ventilator. "

I don't know enough about the manufacturing process to say if it's faster to spin up a new simpler design from scratch, or expand existing lines. But it's worth evaluating.

Yes, and the rest of abstract strongly indicates they're still in preliminary collaboration stages, bringing on subject matter experts to figure out the details. I'm not saying it's not worth evaluating, but it isn't going to solve the current bottleneck. Take a look at the link I provided. Their products are literally tailor made for these exact types of situations. Throw all the resources you can at helping them scale production. If necessary use the DPA to force them to open their designs to other manufacturers that can retool their factories to make even more. Sure, by all means have parallel efforts to evaluate designs that can be cheap & scaled even more effectively, but recognize that such solutions will solve the next crisis, not this one (unless we're still in this one a year from now, which, hell I hope not but it doesn't seem beyond the realm of possibility.)

The US has become engineering/design while manufacturing is overseas. Broad stereotype, but I hope this is an opportunity for the US to recognize that manufacturing may actually be an issue of national sovereignty.

The US is the #2 manufacturer in the world [1] and will overtake China this year to become #1 [2].

[1] https://en.m.wikipedia.org/wiki/Manufacturing_in_the_United_...

[2] https://www.industryweek.com/the-economy/competitiveness/med...

I would bet this is only for final assembly. I seriously doubt there is any "Made in USA" product that isn't completely dependent on some tooling or components made overseas.

Yes, but be careful with that conception. That exact same thing can be said of just about anything made anywhere. This is the nature of globalization of supply chains.

I mean it goes back long before the word “globalization” was used to mean “anything I don’t like that involved more than one country.” There was very long-distance trade thousands of years ago. Not every raw material you might want will exist in your immediate vicinity.

It would be hard to find any product these days that isn't dependent on the world-wide supply-chain, but I agree that how "manufacturing" is quantified and measured leaves a lot of room for tomfoolery.

Couple of things:

- For products containing electronics: short of the electrical components themselves, there is a healthy amount of US electronics+mechanical manufacturing, but it's more geared for lower-volume higher-margin type stuff (think for energy / agriculture / etc.)

- IIRC having spoken to someone at Jabil a few years ago, vague recollection of being told that the US is the largest manufacturer of high volume plastic goods (as well as other products using automated processes). Not so much enclosures for consumer electronics, but rather stuff like shampoo bottles, and that sort of tooling is done here in the US.

- Just keep in mind that manufacturing has a broader scope than what it seems you're implying. Not all manufactured goods involve electronics or injection molding.

Shampoo bottles make little sense to make in China. The processes are highly automated, the feedstock is cheaper in the US (way more petrochemical inputs and cheaper energy) and it would be madness to ship empty shampoo bottles over long distances.

Even US industrials like the metals industry is still chugging along, and some of it even ends up in Chinese products. It's just that the US has shifted to making more specialized metals and alloys, rather than cheap and basic metals.

True on high volume plastic bottles, caps, etc. Those must be manufactured geographically near final distribution, too expensive to ship billions of empty plastic bottles half way around world.

And lots of the tooling for this high volume plastic bottles, lids, etc is made in Germany. Consensus is Germans make best tools for this volume (100’s of millions of parts per year)

Counterpoint / However: A lot of the "made in China" products were developed and designed in the US.

Sure but most Chinese factories operate using manufacturing equipment made in the US or Germany.

This is absolutely and patently false for 99% of Chinese manufacturing. I suggest you watch Strange Parts videos to see what manufacturing in China is actually like before making a fool of yourself.

Final assembly only would be the last strategy applied in the US due to high labor costs. The competitiveness of US manufacturing is due to high levels of automation.

Is this adjusted for PPP?

I wouldn't trust a projection from 2015 (!) about relative US-vs-China manufacturing volume. Hell, I wouldn't trust a projection from 2 weeks ago.

That's a problem. If a country doesn't have manufacturing capacity, other countries can use that as leverage in the geopolitical sphere. This is one example of where the interests of corporations and countries conflict.

That's Taiwan and Hong Kong in a nutshell.

Sadly, true.

The flip-side of globalization is there are unlikely to be any more large-scale conventional or NBC wars (only proxy, cyber and economic wars) because of extreme economic interdependency.

This wont change in a capitalist society. The only ways to fix this that have a chance to actually work that I can think off is 1) Americans work for as low wages as workers in China to compete or 2) non-capitalism. I would love to learn of any other ways but this has been discussed by people way smarter than me for ages and I have seen no other solutions that wouldn't sink the US economy or cause a revolution.

> no other solutions that wouldn't sink the US economy

After this pandemics is over I think we'll know better what "no other solutions that wouldn't sink the US economy" actually means. I suspect that behind the typical talk about sinking "the US economy" is not what it appears to be, especially if one talks about "capitalism" versus others.

Namely, since a some decades ago both China and Russia are technically capitalistic societies. Therefore I interpret the statements only as "will our empire continue to be the empire." The empire is kept primarily with the arms, and they aren't going away, whatever changes.

You seemed to have missed the option that has been driving economic growth for centuries: improved worker productivity through improved technology and methods. A machine can work cheaper and faster than any Chinese worker. Eliminating work is even more efficient than that.

So basically work smarter than harder or cheaper. The way to compete with the Chinese is through better ideas.

That's the theory we heard since 1980s: then Japanese robots will run over everyone. In practice however, you have Chinese workers instead. Outside some very high volume, certain simplicity manufacturing processes it's still mostly manual labor on assembly line.

Yes manual labor is used when it makes economic sense and automation is the same. Robots did indeed take over many tasks, but people still exist and still want to work so they do stuff too.

The idea that automation means people can't or don't work is a fallicy.

Very easy to change with laws. Similar to how laws were passed after 2008 to force banks to be less profitable (they can't trade any more, need more reserve capital, etc.). Very easy, all you need is political will. Trump was going in the right direction with trade war with China (possibly for the wrong reasons), I'm really happy because I predict it will be a political suicide for the Democratic candidate to propose the opposite policy now, so it will become the policy regardless of who wins the election.

Communist China never should have been granted MFN status. That was our mistake. No one in the U.S. feels threatened if Germany, France, England, or any other Western liberal democracy manufactures something. (I make an exception for some goods critical to national security, which we should always have know-how for.) But China is a hostile nation.

When Woodrow Wilson talked about making the world safe for democracy, the flip side of that is that democracy requires safety and security. We liberal democratic nations are capable of playing nice with one another. We will have normal rivalries. But China cannot play nice.

We need to transition away from trade with China, under MFN status.

> would love to learn of any other ways but this has been discussed by people way smarter than me for ages and I have seen no other solutions that wouldn't sink the US economy or cause a revolution.

Yeah, here's one: protectionist tariffs. I once looked into what it would cost to make a pair of pants in the US instead of China. The difference isn't that large; something like an extra dollar goes to shareholders instead of workers. You can see it in the actual list prices of jeans made in China[1] versus USA[2]. They're .... about the same. This same calculation is done in lots of different places: MBA types want that extra dollar to go to shareholders. Well, if they're not allowed to do so, everything works just fine.

[1]https://www.levi.com/US/en_US/sale/c/levi_clothing_sale_us

[2] https://www.allamericanclothing.com/made-in-usa/jeans.html

"Open Ventilator Project

Half the world's population lives on an income of less than $300 usd/month. Who will make ventilators for them?

Consider Egypt, 100m people living on a thin strip of land by the Nile, the Philippines, rural Ukraine, India. A yearly salary may not cover a Chinese ventilator."

openvent.org

Invite discussion.

We are testing our centrifugal compressor for pressure/flow tomorrow, driven by $5 quadcopter motor.

Any turbomachinary engineers in the house? :-)

Maybe if a bit of money would be provided from the $6T, that would help. But at this point I don't see any money being thrown to these projects by the US government, which is just crazy.

>Why do we need more designs? We have designs.

because a cheaper, ubiquitous, and open design could have lead to us having more than enough ventilators at this point in time had we been considering the need earlier. An open design that was prevalent now could allow manufacturers to spin up production without the fear of IP legal repercussions.

Why are people interested in designing such things now? Because the problem has been elucidated and maybe the shortage can be prevented next time.

Something majorly bad for fast production : capitalism-oriented-design(read: profit) high tech machines with heavily unique firmwares and lots of high-cost IP in use inside the mechanism.

The abstract includes this rationale: "Our design is optimized to permit large sale [sic] production in short time and at a limited cost, relying on off-the-shelf components, readily available worldwide from hardware suppliers"

The researchers believe that these could be quickly slapped together in substantial quantities in many parts of the world.

I agree and actually find it a bit insulting/arrogant that so many people think that they can build a better ventilator/mask in days without any knowledge in the fields.

I am appalled to see tv news showing people making home 3d printed masks for use in local hospitals out of PLA and cut up HEPA filters. This is as effective as holding a tissue paper to your face, plus your breath the glass fibers from the HEPA filter you cut up and the bacteria that is trapped in the PLA layers.

No one's claiming to build better versions of these things, but instead reasonable alternatives that are not unobtainium. PLA masks probably are in the category of doing more harm than good though.

But the things ARE the better versions already; they are ubiquitous, the process for mass-production (think of face masks atm) have been developed decades ago. It's a logistical problem caused by a sudden and unexpected surge in demand.

There is no shortage of toilet paper, there's warehouses full of them (https://youtu.be/wA4KS546rZo), it's just a matter of getting them to the shops. Nobody's out there making a better version of toilet paper.

I've seen people swear off toilet paper in favour of the bidet. Perhaps this crisis will wean us off a couple of unnecessary consumer habits.

There is actually a shortage of masks though. Companies that didn't even make masks before are now producing masks. That's not happening with toilet paper because everyone knows that toilet paper use has not actually gone up and demand will crash quickly.

In general, yes.

However, in this particular case we have a paper with 26 authors, mostly physicists and engineers, humbly asking for feedback from the scientific and medical community. Not a group of people arrogantly thinking they have The Solution to our problems.

I assume ventilator manufacturers are currently working overtime to expand production?

I know that Dräger in Germany got an order of 10,000 ventilators by the German government.

Yeah, Resmed here in Australia are doubling/tripling manufacturing capacity. https://www.businessnewsaus.com.au/articles/resmed-ramps-up-...

Why wouldn’t we want people to continue iterating on designs? Should all the world’s designers just start trying to become manufacturing planners? Of course not. This would be a terrible use of their skill set. But more than that, why in the world are you criticizing people who are just trying to help? At a minimum these people are helping to inspire hope.

I suspect existing designs require parts that are hard to manufacture or acquire at this scale.

So reevaluating the design might be out of necessity to work with what is available in terms of materials, skills and equipment.

That’s just my theory, I’ve no evidence to support that.

This a thousand times. Developing a robust manufacturable product, even a simple one, is HARD. It takes multiple spins and loads of testing, not to mention a huge amount of work to make it manufacturable.

Why are we trying to reinvent the wheel. We should be finding simple, battle proven designs and throwing the manufacturing efficiency machine at them. Developing new products on this timeline is exceedingly naive.

I'd like to add that most media professionals and journalists have no clue about manufacturing engineering and how difficult it is to produce something at mass scale.

But they inccessantly write about 3D printing for more buzzword invoked clicks.

>> Why do we need more designs?

The goal is to design a low-cost, simple, easy-to-use and easy-to-build ventilator that can serve the COVID patients, in an emergency timeframe. It should be easy to build locally, its functionality must be easy to verify, and must meet the design requirements.

And not kill patients

Also : cheap

Manufacturers have the world by the balls in a crisis like this, and throwing money at them as they increase their costs is not something a government can do forever.

I'm glad scientists are taking over the means of production here.

Designs haven't kept up with the recent advancement in production technologies

We are working on a version of this which does not require any electronics: https://twitter.com/zackbloom/status/1242156904782139395?s=2...

It uses fluid dynamics rather than a sensor system, simplifying manufacture at scale.

I would like to ask you a few questions:

Is PIP adjustable? Is PEEP adjustable? Is Tidal Volume adjustable? What sort of pressure regulation is required at the input?

Some of your questions are covered in this doc:

https://docs.google.com/document/d/1Hcuu-55q2a3_-LmBwg0uBdgM...

How to potentially get involved, mainly from the point of view of "small scale" manufacture or helping with prototyping?

Asking because a friend at one of the Uni's here in Melbourne, Australia is part of the team that looks after the Uni CNC machines (5 axis) and their 3D printers.

The design in the twitter above looks like pretty much exactly what their 5-axis CNC machines can do. And they were already discussing potentially doing something with the 3d printers.

So, might be a good fit to put them in contact with you? :)

Nice idea, better approach than I've seen popping up everywhere and clearly meant to be an emergency only device. I'm sure everyone has made clear how complicated and dangerous proper ventilation care is. I don't have time to get involved at the moment even though I would love to (expecting a newborn any day now), but a few thoughts.

- Consider the failure-modes of the device. (If inspiration pressure set screw is not mechanically fixed and fails open, you will irrevocably damage the individuals lungs and likely kill them. Similarly, exhalation pressure drop could collapse alveoli and suffocate them). Could also put pressure relief/vacuum break valves on the device, but hard to do accurately and cheaply at small pressure ranges.

- Fail indication. Need indicators in the field to understand whether device is functioning as designed or not. Particularly with high PEEP settings, visual indications of respiration are pretty much non-existent and no way to tell if pressures are causing barotrauma.

- You may want to include guidelines for proper air supply intended for this device as well. Modern ventilation systems have fail-over and redundancy for all critical aspects (electricity, oxygen source, pressure regulation, etc) for respiration. This may be done at the device (taking feeds from multiple continuous supplies) or in the oxygen supply system (multiple compressors connected to a header system, high volume compressed oxygen tank etc).

Congratulations with your baby! He/she is lucky to have scientifically literate parents.

> If inspiration pressure set screw is not mechanically fixed and fails open, you will irrevocably damage the individuals lungs and likely kill them. Similarly, exhalation pressure drop could collapse alveoli and suffocate them

Seems like a worthwhile risk to take on a patient that is going to die within minutes of going off a ventilator that is needed for a patient with a better chance of survival.

Unfortunately, that's a common scenario playing out in Italy right now.

I have been building something very similar to this! We have someone working on the controller PCB right now, and I am waiting for a few parts to arrive Friday so I can finish the proof of concept. Once the bugs are hammered out we will publish the design and build instructions on civilpedia.

I can say for sure, the solenoid valves specified here in this paper are too small to work well enough. This problem has slowed our progress down by a week.

If anyone has questions please ask them here.

If I run a high-tech manufacturing facility that has some extra capacity these days, whose ventilator design should I start producing? It seems so many are springing up.

Whatever you can get parts for, I suppose.

We chose parts you can get from Home Depot and Amazon/Ebay only, except for the PCB, which you will be able to make with hand-soldered components.

Also: make sure you choose a design where it is not possible to over-pressure the lungs. Even so much as 1.5PSI can damage them permanently. As well, the design must never allow the pressure to drop below about 300 pascals (above STP), or the patient will eventually suffocate due to alveoli collapsing.

300 pascals? That's darn near a vacuum. Did you mean not to let it drop more than 300 Pa below ambient?

It cannot go under STP + 300 pascals, must always be positive pressure.

If anyone's wondering, atmospheric pressure is 101 300Pa, so 300 Pa is extremely low.

Does your design also rely on pressurized medical air for operation?

It sounds like this one is using an ESP32 microcontroller (described as 32 bit, arduino-compatible, WiFi+Bluetooth ). What microcontroller are you using?

Is your design open source?

Can you expand on the solenoid difficulties you experienced?

Thanks!

Edit: typo

It can operate from any air source, we're using a free piston hydroponics compressor which is available from eBay/amazon vendors for $100. I have used these compressors for years with no reliability issues.

We will be using an Arduino uno because they are so easily available, no wifi or bluetooth, last thing I'd want people to deal with is bluetooth bugs in a situation like this...

The solenoids I have tried (many) are too restrictive for air flow, and after some minutes I felt suffocated when using them. Most solenoid valves don't have orfices greater than 2.5mm, and we found even 4mm was not enough.

It will be open source, yes.

Make sure you are using a medical grade (oil and particulate free) compressor, because aerosolized machine oil and micro metals are super bad for people to breathe in.

The free piston compressors don't use oil as far as I have been able to tell. I believe they are diaphragm pumps.

Cheap compressors (even labeled oil free) will still have residue machine oil on internal surfaces from the manufacturing process. Chinese manufacturers usually surface coat metal to prevent rusting during shipping.

It might not be enough to bother you or I, but if someone is respiratory compromised to the point they are on a vent, they really need medical grade oxygen.

OK we can recommend a filter if the compressor is of unknown quality.

I have tested our design with supplemental air from a Phillips EverFlo and it still works well.

That was one of my first reactions reading about this design as well, that WiFi is likely a liability in this case (not to mention espressif's security track record is not the best) despite the potential ease of provisioning. I would prefer either a microcontroller with ethernet or acting as a USB network device. Then it would still be as easy as plugging into the device with a laptop and navigating to a web page to configure the ventilator, although one couldn't easily do it from a smartphone or tablet.

Is a less-complicated (and more easily verified) PCB too difficult to design? Arduino may be easy to use for proto, but not going to be simple to verify. Plus, you are now slave to their supply chain, for a need that may be much simpler than what the Arduino board offers.

The Arduino Uno MCU is fairly widely available: https://octopart.com/search?currency=USD&q=Atmega328p&specs=...

although there are others MCU's with even better availability (e.g. the SAMD21, which also has plenty of dev boards and it seems like Microchip has extensive stock on hand, for example https://www.microchipdirect.com/product/ATSAMD21J17A-MUT?pro... ). One can take any of the devboards a a reference design.

Of course, I read the original comment as relying on the entire Arduino Uno board, which is both expensive and restrictive to your supply chain. Individual components, such as MCUs could more easily be selected to avoid those two issues.

Awesome work! What is civilpedia?

https://civilpedia.org

As an aside, your adammunich.com website just displays a "Please click the allow button to show you're not a robot" message. With no Allow button anywhere.

With variations on it (but same problem) with each page load.

Capture fail, or joke website?

Worse, I'm getting a pop-up requesting I allow notifications. No, thank you. It seems that if I don't allow notifications, I can't view the site - and I'll keep getting the pop-up. This is one of the more intrusive and off putting experiences I've had on the first time load of a site.

Edit: After clicking "Block notifications" about 10 times, and being redirected to a different "redfundchicken" address each time, I finally end on skyprize22.live, an obvious scam site.

I believe adammunich.com redirects to a scam site.

I have a bare PCB and PCBA CM that is still running. Let me know if that can help in any way.

We can reprogram our lines to make any type of PCBs and assemble them (we have inventory of most standard components).

Hey you appear to have been shadow banned back in 2017 for no reason I can see. I think you can email the support address to fix it?

Yes, that was a mistake at our end and fixed now.

All: if you see a banned user that shouldn't be banned, please let us know at hn@ycombinator.com. We try not to get this wrong, but we (and/or software) sometimes do. It's a big contribution to your fellow users to let us know so we can fix it.

Happy to help on EE side. PCB, firmware, verification, etc. https://www.linkedin.com/in/thenatefisher/

As many have said it seems everyone is creating designs for ventilators, but few are producing large numbers that are being used.

But I'd guess that 99% of the effort required to create a ventilator is not the design of the mechanism pumping air into lungs but guaranteeing it is reliable, maintainable, easy to use, is hygienic and can be cleaned safely, obeys regulations and manufactured.

It doesn't matter if there's a crisis on or not - hospitals will get sued if your Heath Robinson style ventilator breaks and kills a person, however sick that person is.

It is also worth noting that the fatality rate of cases that get artificial ventilation is about 50 % even in ideal conditions. While it can save a lot of lifes, keeping the total number of cases low is still absolutely crucial.

Agreed, It would make seem to make more sense for people to think about how to make people stay further apart, or designing and creating face masks or other 'gadgets' that stopped the spread of the disease.

Given that the recommended distance is 2 metres, I thought it might be fun to provide everyone with a metre stick, and if you can only just touch sticks then you're the right distance away. + it gives an alternative to the handshake!

If you are an adult, a meter stick is attached to your shoulder - just extend it.

Being pedantic, arm lengths vary from ~60cm to ~90cm. So not quite / only if you're a very large human!

Thankfully, in the US the recommended distance is only 6 feet (1.8m) :)

Anyone have any idea how different mechanical ventilators are from CPAP machines? A lot of people given CPAP machines can't tolerate CPAP therapy and as a result there's a shitload of barely used and unused CPAP machines all over the US.

The ventilators used for severe cases of COVID run at much higher pressures.

Even AvE got into the fabricobbled ventilator prototype business.

https://youtu.be/N1OFMZDNKvU

https://youtu.be/t324iJOYoXI

And it looks rather similar to this one.

Just as a kind of PSA:

In light of ventilator shortages, I encourage you to look up non invasive airway clearance methods. These are medically recommended for people with serious, chronic lung issues. They've been around a long time. I'm not seeing them get much attention compared to the ventilators.

As useful background, here's the UK's Medicines Agency "Specification for Rapidly Manufactured Ventilator System (RMVS)" that need to be followed before any hospital would use one of these devices:

https://www.gov.uk/government/publications/specification-for...

This paper is 7 pages long and has only 4 diagrams. Here are the testing videos: https://tinyurl.com/uurapy3

I applaud the initiative, but even for something macgyvered together in a hurry, I think a more rigorous approach is needed before deploying something like this en-mass.

"Our design is optimized to permit large sale production in short time and at a limited cost, relying on off-the-shelf components, readily available worldwide from hardware suppliers."

Those shelves, I'm afraid, are going to be empty. Manufacturing is optimized for "just-in-time" production, not "just-in-case" stockpiling. Perhaps I'm the wrong person to consult, but I wouldn't know how to procure ample amounts of "Medical Care Flow Meters" or "Spirometers".

Somebody figure out a way to solve the problem with plastic bags, PET bottles, outdated smartphones and old PC fans. I've got a strategic stockpile of those to give away, just like every other nerd on the planet.

I've read that one ventilator requirement for COVID-19 is an output filter that prevents the virus (and other viruses and bacteria) from getting into the room air. Otherwise a ventilator is pumping virus into the room air which increases risk for other patients nearby and medical personnel. I'd imagine that worst case these ventilators might be used in large arena's filled with beds rather than positive pressure ICU rooms. Maybe HEPA filters for air purifiers would work? Or HEPA vacuum bags? Or the big filters trucks use for air intake, I think those were used in some early HEPA air filter devices. Not sure if they are fine enough filtering to stop a virus though.

I recently saw the three component ventilator[1] and was immediately impressed.

No electronics - huge plus for scalability

1-to-N - one ventilator can serve a hundred or more intubated patients - again a massive boon to scalability and dovetails nicely with the armies approach to retrofit empty hotel rooms with negative pressure kit.

PEEP and moisture control - this was in the version 2 model

Love the groundswell of new ideas here. Traditional designs were made for individual patients with and a broken procurement process - these new versions can address a large volume of patients in a distressed supply chain.

[1] https://youtu.be/N1OFMZDNKvU

> 1-to-N - one ventilator can serve a hundred or more intubated patients - again a massive boon to scalability and dovetails nicely with the armies approach to retrofit empty hotel rooms with negative pressure kit.

That's... scary. I seem to remember that each ventilator needs to be tuned to a patient's pulmonary capacity. Otherwise, you risk either not providing enough air or exploding the lungs.

Couldn't that be handled my modifying the oxygen mixture per patient? My concern would be contamination between patients on the same system. People are ventilators are typically immune compromised. The positive pressure helps avoid this, but I'm not sure it's enough pressure.

I propose a shared manifold ventilator based on plumbing and pneumatic parts and pieces. I just wanted to point out that such a device could handle 20 or more patients at once and uses well-established principles of reliability. https://bit.ly/c19ventilator

I noticed the "O2 Therapy Humidifier" and other components. How does this ventilator fares against a AMBU bag ventilator?

Right I'm making an effort to acquire DIY to build a ventilator that squeezes an AMBU bag. I found it incredible easy to make and scale, total cost around 300 euros/324 USD.

Maybe you would be interested in this:

https://www.oxygen.protofy.xyz/

I understand people's needs to do something and if this helps people feel better I am all in favour of it. The engineer in distress builds.

But this design is missing some fundamental things which makes me wonder if they've really understood the requirement.

The first is that there is no flow monitoring so no way to adjust tidal volume. Since this is the most important parameter to adjust and control in treating ARDS, that lack is worrying.

Their taxonomy of ventilatory modes is wrong.

All the diagrams and text refer to a non-invasive ventilation using a mask but that is not where the greatest shortage is. There are a lot of BIPAP and CPAP machines which can be used for that sort of thing.

There is a consistent reference to a PEEP of 5cm which is too low for the desired use case. I know the design is adjustable but the fact that this is not acknowledged is again a sign that they may not have understood what is needed.

There is no blending arrangement for running on an O2/air mix. I don't understand why they did not add that.

I don't object to this stuff, it's all a bit of fun, but the ventilator shortage is going to be fixed if it is by combining the resources of idled factories with mass production capabilities with the knowledge of ventilator manufacturers.

When we did this in WWII, we did not ask Ford and GM, "Could you build us a bomber, please?". They collaborated with plane manufacturers to convert their factories to produce existing designs.

If I was in charge of this effort, here is what I would do:

First, in the near terms, make sure that existing manufacturers have what they need to boost their own production.

-People who work in aerospace (or F1 racing, of a few other things) for instance have experience in hand assembly of critical components following procedures precisely. This is a better resource to draw on than other manufacturing workers such as auto workers. You could bulk out the assembly teams in existing manufacturers with these people.

-What parts will they soon run out of? If their supply chain can't deliver, what alternatives can be rapidly qualified for use? Valves and sensors could be sourced from non-medical-grade manufacturers, preferably aviation or other safety critical because again - they live in a similar world as far as traceability and quality goes.

In parallel you work on a basic design that meets the requirements of treating ARDS. You do that using the engineers who design ventilators anyway, together with supply chain and manufacturing experts from your other industries so that you design something that the supply chain can either produce or more likely they can produce sub-assemblies and/or parts.

I understand these devices take 2-3 years not reach market. What’s the risk that some of these devices aren’t effective or too overpowering? Is there a test harness that can grade these devices?

There is Czech initiative to provide same and being available under Open Hardware license soon.

https://www.corovent.eu/

Another one:

https://www.oxygen.protofy.xyz/

If you have not submitted yet, consider submitting to the DoD Hack-a-Vent challenge: https://vulcan-sof.com/login/ng2/submission?collectionUuid=2...

Unbelievable stuffy I keep reading on ventilators. Just unbelievable. If you want to kill people by the thousands, please continue. The good news is no medical professional in their right mind would use one of the hot messes so many are "inventing". Parts from Home Depot? Really?

These are life critical systems designed with serious fault tolerance in mind. Home Depot parts, randomly sourced solenoids, valves and fucking Arduino's? Has everyone gone insane?

Here, go read the Wikipedia page on ventilators:

https://en.wikipedia.org/wiki/Ventilator

Let me highlight a few sections. Like this one:

"Because failure may result in death, mechanical ventilation systems are classified as life-critical systems, and precautions must be taken to ensure that they are highly reliable, including their power-supply."

"Mechanical ventilators are therefore carefully designed so that no single point of failure can endanger the patient. They may have manual backup mechanisms to enable hand-driven respiration in the absence of power (such as the mechanical ventilator integrated into an anaesthetic machine). They may also have safety valves, which open to atmosphere in the absence of power to act as an anti-suffocation valve for spontaneous breathing of the patient. Some systems are also equipped with compressed-gas tanks, air compressors or backup batteries to provide ventilation in case of power failure or defective gas supplies, and methods to operate or call for help if their mechanisms or software fail."

I mean, seriously, read that again right now. If you have zero experience in fault-tolerant design of electronics, mechanics, pneumatic, hydraulic and software systems, please recognize the dangers of the Dunning-Kruger effect and stop.

If that wasn't enough, there's this:

"In Canada and the United States, respiratory therapists are responsible for tuning these settings, while biomedical technologists are responsible for the maintenance. In the United Kingdom and Europe the management of the patient's interaction with the ventilator is done by critical care nurses."

In case the point isn't obvious, what this means is that certified professionals have to operate these devices. They are not going to get anywhere close to a pile of parts from Home Depot and the local auto repair shop. They are trained to operate reasonably standardized equipment and expect form, function and reliability that comes with time-tested, certified and well proven professionally manufactured equipment.

Want to build something to help? Maybe figure out how to make hospital beds. My guess is there's far less likelihood of killing people with a frame and a matress than with a pile of Home Depot parts and an Arduino pretending to be a ventilator.

Why are these posts even permitted on HN? This is unproductive dangerous quackery. Nobody is going to invent anything useful. Go help existing companies stamp out more units of their designs. I'm sure they can use the help.

> The purpose of this paper is to disseminate the conceptual design of the MVM broadly and to solicit feedback from the scientific and medical community to speed the process of review, improvement and possible implementation.

No, the purpose of this paper is to waste everyone's time. Let professionals handle ventilators. Stop thinking this is something a bunch of mavericks are going to Superman into existence with a bunch of parts from Home Depot.

I agree that a well-seasoned ventilator design would be much preferable. The question is, can we get that? I'm not involved in this effort (I found out about it through a forwarded email that's being passed around between physicists), but I suspect that nobody involved has the ability to speed up medical device manufacturer's production or supply chain. The point of "parts from Home Depot" is to bypass the likely specialized supply chain that may be difficult or impossible to scale up.

I don't mean this in a disparaging way. I took a look at the list of authors and my first thought was "A bunch of physicists without a clue". There is a massive difference between bolting a bunch of parts together to mass manufacturing a reliable life-critical device to deploy to hospitals. We seriously need to stop with these pointless games and throw resources at real proven designs by real companies with experienced multidisciplinary teams. Seriously, I don't know how else to say it.

Let me give you an idea of just how stupid it is for a bunch of guys pulling parts out of Home Depot to decide they are going to make a ventilator for mass manufacturing:

Elon Musk decided to make ventilators at SpaceX. I've done work there. I know exactly what capabilities exist at Hawthorne. Let's just say that, compared to Home Depot, it's a universe apart.

Did he go off to invent them from scratch? No, they had high level engineering meetings with Medtronic. His opinion is summarized in one comment and one action. First, among other things, he said, "Impressive team". Next, he bought 1,200 ventilators from China and brought them into the US.

He also recognized you can't Superman ventilators. Not that simple. Not if you want to keep people alive. Not if you want to get them to market when needed.

There are consequences for allowing our industrial base (I include Europe) to erode to such an extent that we depend on China for just about everything. Here's the perfect storm that is going to show us just how stupid our political class has been for the last 50 years. And somehow everyone is angry at Trump. Medtronic can't scale their ventilator manufacturing because the imbeciles going back decades before him were incompetent political actors who only cared about their own careers and political goals rather than the interests and needs of a nation. Now we get to pay for it.

Superman does not exist. We might just have to face a reality that will be cruel punishment for our failings. I hope we learn something by the time this is over.

> Here's the perfect storm that is going to show us just how stupid our political class has been for the last 50 years.

Doubtful. Once all this blows over the older patterns will resume.

I hope not. I hope people learned a lesson. What an expensive lesson to learn. For what? To be able to buy cheap shit at Walmart? Brilliant.

Known supply-chain vulnerability hasn't transformed the US defense industry. Search "report on us defense supply chain vulnerability"

This design is hardly from scratch; it's based on a simple old design from the 1950's with components chosen for availability. I have no idea what the relative shortcomings of the old designs are, but nobody is trying to design a "modern" ventilator here (except maybe Elon Musk?). I agree that it is very risky to put something like this out there without sufficient testing, and I'm not sure if it's a good idea or not, but the likely alternative to the improvised ventilator may be no ventilator.

Complaining about globalization is certainly not likely to help. Anyway, I'm not sure the location of Medtronic's factories is that important. Most likely mass-manufacturability and high-availability of components was not a important design driver if it was intended as a high-value low-volume device.

The issue isn't that this is based on a design from the '50's (whatever that might mean in practice). There's a massive difference between throwing a bench prototype together and making thousands of repeatable and reliable copies of the same device. For example, how do you guarantee it will work reliably 24/7 for weeks on end without changing settings, breaking down or killing someone?

I can find the blueprints for the engine in a 1967 Ford Mustang and machine one from scratch and probably make it work. From there to making tens of thousands of copies of that same engine it's a different matter. It's a million times harder if I have to ensure a certain level of reliability, smoothness, wear rate and longevity. And we are not even talking about a critical life support device.

Regarding globalization and the supply chain. Believe it or not, we almost can't build anything in the US or Europe without Chinese components. This spans almost anything you can think of, from wires to chips and displays.

The displays are a good example. On a good day lead times for displays and related components range from, depending on what you are buying, 8 to 20 weeks. This is for stock product. If, on the other hand, you are using a custom display in your product, perhaps one with custom indicators, lead times can easily double. We don't make ANY of that stuff in the US or Europe. And most displays are sole source.

So, if you, all of a sudden, need to make 100,000 more units of something immediately --within two to four weeks-- it is about as close to impossible as you can get and truly impossible without supernatural intervention.

Having a local supply chain may not necessarily modify that, yet it would provide you with far more control.

Extend that concept to almost every single component in a machine and the problem we have should become very evident.

All the eggs were in one basket.

I welcome medical device manufacturer experts to put out a proven, open, manufacturable design, but I'm not holding my breath.

The real issue here is probably not where the factories are located, but the for-profit medical device industry where flexibility and excess capacity are liabilities. The same model that is good at reducing the price of consumer crap is probably not the the right model for things we may actually need. DOD supply chains are much more nationalized but I doubt they are substantially more flexible because there is not much incentive for a for-profit company to do that.

Why would you think that? Wouldn't these producers realize this as the greatest opportunity for their devices?

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