COVID-19 Printable PAPR (Powered Air Purifying Respirator)  

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

New flexible fit Halo first more people, prints faster, and better for extended wear.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Posted by: @dee

[...]I was curious if your design could work with viral cpap filters that are more easily available. I was not sure if there was a substantial airflow / diameter distance that would throw the pressure off. Also was not sure if the viral rating was quite as high as what you are using.

Thanks!

Hi dee,

just a wee side note on some filters/HMEs out there. I spent substantial amount of time looking into these.

Ideally the filter you're looking at should have a proper data sheet, either in the package they come in or on the manufacturer website. In a lot of cases manufacturer is not the marketing brand. For example here in NZ a company named Jackson Allison provides filters but does not produce, they source from two different manufacturers in Malaysia. In such a case I would try to get the documentation from the manufacturing company. Most of them will have contracted the testing to a accredited testing lab.

Some of the filter numbers explained:

Filtration rate should be tested and stated for bacterial and viral retention. Electrostatic filters should achieve minimum 99.99% viral filtration HEPA filters should achieve 99.999%. Ideally one order of magnitude higher. I am aware of two brands that achieve those numbers, that's Draeger (safe star) and Intersurgical (don't know their branding from the top of my head). HMEs are not that useful for this application.

Anything below this rating is a compromise.

hth

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

HMEs are not that useful for this application.

Good clarification that HME's not all also filters. HMEF's combine the humidification and filtering functions.

I should have been more explicit regarding HME vs HMEF's, but overlooked that as we only have HMEF's at our hospital and plain filters at our outpatient sites. 

BTW, I believe the new flex fit Halos will address your head size issue. The range for customization is much larger now.

Spreading awareness today

Met up and gave a Halo to an Evergreen (Kirkland, WA) hospital anesthesiologist. He'll be raising awareness there. On the way home, I walked into Swedish Issaquah hospital unannounced. Wearing the Halo PAPR coming in the door gets big smiles and piques curiosity. Their screening and COVID response RN's were absolutely delighted to see it in action. Same when I showed it off to an infection control admin. Those on the ground, who need to USE PPE, immediately understand the Halo PAPR, even if they have never seen a commercial PAPR. Left them the instruction links. It felt really good to spread the word.

Everybody wants a picture of me wearing it and asks if it is OK to post on FaceBook.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

You are going to be famous. 👍 

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

I don't know about "famous" but I just want to push out a useful concept for this type of emergency.

Low level PPE we can deploy in good number, but there are plenty of situations where we (providers) wish higher level protection, but the limited stock of PAPR's and CAPR's, heck even N95's means you simply won't be issued higher level equipment. Your exposure profile doesn't match today's criteria which varies perceived supply availability. 

The Halo PAPR puts high level PPE into the reach of more people. They just don't know such a thing is possible.

Heck, I can't even raise a single message response from Prusa.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

@guy-k2

"I don't know about "famous" but I just want to push out a useful concept for this type of emergency."

Fame comes to people not looking for it. Our BC Provincial Medical Officer is just doing her job, but musicians are writing songs about her, artists are painting her portrait everywhere and someone is making buttons of her. Other Medical Officers or equivalent are looking at her for inspiration. She wasn't looking for fame. We dumped it on her!

"The Halo PAPR puts high level PPE into the reach of more people. They just don't know such a thing is possible."

Maybe it is time all the readers of this topic sent the link to this discussion to any medical and front line worker they know anywhere in the world. I wonder if my local news station would be interested????

"Heck, I can't even raise a single message response from Prusa."

If it was me, I would not expect one. NIH (Not Invented Here)

I am sure that your PAPR will keep many people safe and some may not even know it.

One man can make a difference.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Posted by: @guy-k2

I don't know about "famous" but I just want to push out a useful concept for this type of emergency.

Just want you to know you're an inspiration, Guy. I keep looking at your posts, shaking my head and going back to printing NIH shields. Amazing stuff. I'm going to be pretty pissed off if we don't take some major lessons learned from all this.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Thanks. The encouragement goes a long ways. I keep plugging away at government, media, and local site administration. It's super tough from the top. They don't understand how much higher level protection this can provide. All they want is whether it is regulatory approved so they don't need to be responsible. From the bottom up, it is a heck of a lot easier - particularly if they are an actual medical care provider who can actually understand how the Halo PAPR works.

So, I get weird, two phased conversations that basically boil down to.

1. We are in a quandry what to do with this. We can't officially recommend it because it isn't approved.

Which is followed with off the record 

2. This is amazing what you have here. It could really change things.

But admins are not exactly known for bravely stepping out of line. They know it works, but won't endorse its use. Thankfully, most are able to grasp it well enough not to block its use. 

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

@guy-k2

So tonight is my break night from printing.......and my bourbon prevented me from reading this whole thread.  Have you tried submitting to the NIH and jumping through their hoops?  I feel your frustration though, hospitals here won't accept any homemade PPE due to "potential liabilities".  This does look awesome tho!!!

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Yes, it was submitted to NIH. I don't hold out a lot of hope someone there is willing to OK it without FDA. The operating principles are dead simple and it's using known good viral filtering. However, it does a high level isolation job, but allows variable materials. I don't specify or limit exactly which polytheylene bag, which model anesthesia viral filter, etc. The basic design was to allow variable materials, but still get the job done. That is perfect for this type of emergent need, but the exact opposite for making a government employee say yes. It requires the ability to say, yes and be brave enough to do it.

I'm not being brave when I put on a Halo PAPR. I'm trusting in already known filter engineering.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Reinforced and refined fan mounting points on the Halo loops. R2 files are now available with the changes.

Look for....

Halo Flex Fit Loop More Slope 46 r2.stl

Halo Flex Fit Loop Std Slope 34 r2.stl

Fan mounting point

Close detail of fan mounting point. Holes of fan mount band connect to this downward hook.

User engages bottom of hook first. Then band snaps over hump on top of hook. Let's user adjust height of fan without tools. 

More blower fans

Because the current 51 mm blower fan is going to be in limited supply, I have ordered some alternatives to test.

BFB0512HHA-CZMQ

BFB0512HHA-CF00

CBM-5020V-152

BFB0512HA-C

They will each need to be mounted in the BS Halo PAPR and tested for flow adequacy. I'm the usual guinea pig who gets to wear each one for at least an hour while measuring my pulse, respiratory rate, saturation, CO2 expired and CO2 inspired concentrations. Once a fan / output valve combination is confirmed as OK while sitting, it also needs to be checked while walking at moderate speed and some stairs.

All the above fans are in the correct spec range and available in good quantity. I think more than one will be suitable, but won't know until I get actual measurements and a couple hours of wear time.

Actual Use

Here is unedited, 30 minute video of the PAPR being worn during a general anesthetic case. This is a single take during a 9 hours of wearing the PAPR while taking care of patients. It's not just a theoretical device. Notice how clearly you can see my face. That gives you an idea of how well I can see out of the PAPR. No problem seeing well enough to perform anesthesia procedures like intubation and line placement.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Wore the PAPR with a BFB0512HHA-CZMQ Delta fan for 11 hours straight work hours in the operating room today. Flow rate is a bit lower than the original fan, but doable if you don't walk fast. It was fine for pushing a patient on gurney at a moderate pace. Noise level is lower than original fan. Still, after 11 hours of continuous wear, my ears have a little bit of ringing. Forehead skin is fine after that long of a session.

I kept track of my respiratory rate and it never went up appreciably nor was there ever a pressing sense of being out of breath. Formal CO2 measurements are yet to be completed, but given this successful extended wear session while working, I will wager they will be fine.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Where can I find the parts for the O2 fed Halo design? I would like to try and convert that into a helmet ventilator for my 91 year old grandfather that just tested positive for Covid.

I think that a lot of the same concepts for PAPR can be applied to a DIY low cost helmet vent. The Helmet Vent looks like very promising low risk treatment options . The problem is they are in short supply…

https://www.uchicagomedicine.org/forefro...

Any advice on altering this Halo PAPR to be a helmet ventilator would be much appreciated. Thanks you and congrats on an awesome project!

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Sorry to hear of your grandfather's illness.

O2 fed configuration was deprecated a while ago, but if one were desperate to run in O2 fed configuration, all that would be needed is to tape the end of an O2 tubing to the side of the halo loop. No fan mount would be used, but one flutter valve would be needed. Flows would need to be at least 12 L or higher, adjusted to keep adequate inflation and CO2 clearance.

Although I did record via gas monitoring that this will deliver (better than rebreather mask) FiO2's of 97%+, this is a hazardous configuration. There is significant fire risk when working with such high concentrations of O2. Any spark and wearer likely dies. O2 supplied configuration can only be done in spark and fire free settings.

I recommend against running the system in O2 configuration for most users. 

Therapeutic use claims are outside the scope of this device's usage intent, but I have suggested it to some of my intensivist colleagues after seeing how high O2 delivery it is capable. It is similar to the helmet or bottle devices, but no clinical attempts for intentional O2 supplementation have been made with this setup.

Usage would need to be continually monitored. If a wearer fell asleep and the O2 flow failed, the weare would die.

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Gas monitoring tubing is taped under my nares to sample inspired/expired gas

Added surgical mask

RE: COVID-19 Printable PAPR (Powered Air Purifying Respirator)

Baseline gas measurements on room air without PAPR

Baseline in Bunny Science Halo PAPR