PPE Testing Hack Chat

Hiram Gay and Lex Kravitz will host the Hack Chat on Wednesday, June 17, 2020 at noon Pacific Time.

Time zones got you down? Here's a handy time converter!

When the COVID-19 pandemic unfolded in early 2020, the hacker community responded in the most natural way possible: by making stuff. Isolation and idleness lead to innovation and a creative surge as hackers got to work on not only long-deferred fun projects but also potential solutions to problems raised by an overloaded medical system and choked supply chains. And so workshops and hackerspaces the world over churned out everything from novel ventilators to social-distancing aids.

But perhaps the greatest amount of creative energy was set loose on the problem of personal protective equipment, or PPE. This was due in no small part to predictions of a severe shortage of the masks, gowns, and gloves that front-line medical workers would need to keep them safe while caring for pandemic victims, but perhaps also because, at least compared to the complexity of something like a ventilator, building a mask seems easy. And indeed it is as long as you leave unanswered the crucial question: does the thing work?

Answering that question is not as easy as it seems, though. It's not enough to assume that putting some filtration between the user and the world will work; you've got to actually make measurements. Hiram Gay and Lex Kravitz, colleagues at the Washington University School of Medicine in St. Louis, actually crunched the numbers on the full-face snorkel mask they modified for use as a face shield for medical PPE, and they have a lot of insights to share about proper testing of such devices. They'll join the Hack Chat this week to discuss their findings, offer advice to builders, and reveal how they came up with their idea for a different way to build and test PPE.

Event Logs

Collapse

Hack Chat Transcript, Part 2
Dan Maloney • 06/17/2020 at 20:05 • 0 comments

Lex Kravitz12:41 PM
Many people started 3D printing face shields (clear plastic protector with an FDM holder). I thought that was an amazing demonstration of distributed manufacturing of 3D printing being able to produce parts that were overwhelming commercial manufacturing sources

Dmytro joined the room.12:41 PM

Hiram12:41 PM
More than logistics, the manufacturing capacity was not enough. This was pointed out by one of the last remaining face mask manufacturers in the USA

Joseph Stavitsky12:42 PM
Yeah I'm a very late adopter and this is one of several cases where that policy bit me in the butt

Hiram12:42 PM
Face shields help, especially if someone coughs directly to someone's face, but without an airtight seal, viral particles could theoretically get through

Joseph Stavitsky12:45 PM
@Hiram what's that you say? Globalized manufacturing supply chains can't physically meet demand fast enough for emergencies? This is my shocked face

Hiram12:45 PM
Even a full face mask on someone with a beard will decrease the efficiency significantly. From all the testing it really makes you wonder what kind of protection, if any, most homemade N95 masks are providing. Probably very little

Hiram, where does your mask exhaust? Through the N95 filters or through a separate port direct to the air?

William12:47 PM
The full face snorkel masks have an exhaust port on the front, in front of the mouth. They're unfiltered.

Hiram12:48 PM
The air resistance of the filters and lack of water pressure on the mouth exhaust mushroom valve will result in most of the air exiting through the mouth and a smaller fraction through the filters. If the mouth valve was sealed, then it would all go through the filters on top of the head where the snorkel attaches

William12:48 PM
Physicians in Miami we work with have been putting surgical masks over the mouth area. It looks like a robot with a face mask on.

Lex Kravitz12:48 PM
@William haha

William12:48 PM
It's REALLY funny looking.

OK, I see it now. Yeah, I'd think moist breath going back through the filters would be a big problem

Hiram12:49 PM
I think the COVID crisis has highlighted we need more local manufacturing of PPE so we are not vulnerable to global demand, supply chain, logistics, ...

Hiram12:49 PM
The mask looks like Shrek

William12:49 PM
The photo of the face masks over the snorkel is here: https://www.protect-mi.org/reusable-face-shield

Yeah, and not just PPE. Lots of lessons to learn from all this

Bharbour12:50 PM
+1

William12:50 PM
It's not as funny head-on as with the side view. :D

Hiram12:51 PM
I think one good thing about 3M filters is that there are many filter options that could do the job. Some have extra filtering features that are unnecessary. The ones we tested were mostly purely particulate filters

Lex Kravitz12:51 PM
@Dan Maloney Agreed - I was blown away by the 3D printed face shields that many groups around the world were making, that's the first time I've seen distributed local manufacturing happen at that scale

Hiram12:52 PM
Anesthesia developed masks mainly focused on using commercial ventilator filters, some of which worked better than others

William12:52 PM
The 3D printed face shields have been amazing, but also pretty scary.

Did you ever toy with the idea of PPAR - powered air-purifying respirators?

https://www.millerwelds.com/safety/respiratory/powered-air-purifying-respirators-m00482

MILLERWELDS

Powered Air Purifying Respirators (PAPR)

ClearLight™ Lens Technology Optimizes contrast and clarity in welding and light states, while providing a brighter light state to increase helmet-on time for non-welding tasks, enhancing visibility and reducing eye strain. Learn More

Read this on Millerwelds

Lex Kravitz12:52 PM
To follow up with Hiram, we also learned the limits of using different filter designs in a 3D printed design. I mentioned above that we gave up on using HEPA vacuum cleaner filters. We also found the Honeywell threaded filters weren't...
Read more »
Hack Chat Transcript, Part 1
Dan Maloney • 06/17/2020 at 20:05 • 0 comments

Lex Kravitz11:46 AM
Hi!

Lex Kravitz11:46 AM
Thanks for setting this up!

You bet. Thanks for suggesting it, and for your time today.

Lex Kravitz11:49 AM
You're welcome! I hope Hiram shows up, he's the one who actually knows about the testing procedures :)

William11:49 AM
Hi Lex, Hiram, did you get the email I sent to Dan?

Lex Kravitz11:50 AM
Yup, thanks for forwarding that info I think we'll start the chat with a discussion of that, and how these emergency adaptations are not FDA approved

William11:51 AM
I have been working with Ocean Reef Group, and using their APA adaptor for the Aria snorkel mask that you're showing here.

Lex Kravitz11:51 AM
Cool! Do you work in healthcare? Or medical devices?

William11:52 AM
I develop scientific equipment, I'm a PhD analytical chemist.

William11:53 AM
I have translated spectroscopy equipment to medical applications, and done in vivo human research at the University of Michigan Hospitals and at the VA.

Lex Kravitz11:53 AM
Cool I'm a neuroscientist but do a lot of 3D design and electronics work for our neuro experiments, and got in touch with Hiram back in March when he was looking for some help making scuba adapters for use in his radiology practice when they couldn't obtain adequate PPE due to shortages

William11:54 AM
Our group in Michigan tested out a couple of adaptors equivalent to the Pneumask and MasksOn.org adaptors (simple mechanical adaptors from the snorkel mask to inline viral filters), and we found significant increases in CO2 in the inlet airspace compared to what we got when we used the mushroom-valve adaptor from Ocean Reef, so we discontinued our development project on the snorkel mask adaptors.

William11:55 AM
Have you guys tried the Ocean Reef APA adaptor in any of your testing? They have EN (european certifications) on their respirator solution, but haven't gotten the US CDC/NIOSH approvals for use in healthcare settings yet.

https://oceanreefgroup.com/covid19/

Lex Kravitz11:56 AM
Hiram did all of the testing, I'm not sure if he got the Ocean Reef adapter but he should be on the chat soon!

Hiram joined the room.11:59 AM

William11:59 AM
The most complicated piece of this PPE is how so many people got feedback from FDA (CDRH) that the snorkel mask qualified as a face shield. But the snorkel masks are being used with air filters, which means they're respirators, and don't qualify under the FDA EUA as face shields, and instead need CDC NIOSH approvals.

Lex Kravitz12:00 PM
Hi Hiram!

Hiram12:00 PM
Hello, is this audio or just text

OK, looks like both Hiram and Lex are here, so let's get started. Welcome everyone, I'm Dan and I'll be moderating today. We have Lex Kravitz and Hiram Gay today to talk about testing for an emergency PPE they made.

Just text, Hiram.

Daren Schwenke12:01 PM
Only if you play Wargames.

Hiram12:01 PM
OK

Daren Schwenke12:01 PM
*crickets*

Can we start out with a little about yourselves, Hiram and Lex?

Julie joined the room.12:01 PM

@Daren Schwenke - Excellent classical reference

Lex Kravitz12:02 PM
Hi all! To give a quick introduction I am a neuroscientist at Washington University in St Louis, and I do a lot of 3D printing and electronics related to our neuroscience experiments. I was contacted by Dr. Hiram Gay in March to help with adapting scuba masks to be used as personal protective equipment PPE in his radiology clinic.

Hiram12:02 PM
My name is Hiram Gay, I am a radiation oncologist at WashU in St. Louis. Specialize in head and neck and prostate cancer

Nicolas Tremblay joined the room.12:02 PM

Lex Kravitz12:03 PM
I can talk about the 3D design and some of out experiences there, Hiram can talk about the testing that we performed, and what it takes to test improvised solutions

Hiram12:04 PM
One of the satellite offices I direct treat between 20-50 patients a day. Each treatment course is from 1-44 days. Our therapists have a lot of patient exposure and can not social distance. This was the motivation...
Read more »