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Hack Chat Transcript, Part 2

A event log for Open-Source Medical Devices Hack Chat

Tarek Loubani

lutetiumLutetium 01/29/2020 at 21:050 Comments

@riley.august sorry, (enter to send was selected) anyways there are bluetooth stethoscopes, but as stated they are expensive, of course there must be a way to make them more accessible

Tarek Loubani12:16 PM
If you scroll up, I answered a similar question

brian dolge12:16 PM
When I made the stethoscope I had to buy rubber things for the earpeices. Have you considered modeling some in flex filament? They were not cheap.

Tammo Heeren12:16 PM
3D printing is challenging, as it's not cheap in quantity and of quite variable quality

Dr. Clint LeClair12:16 PM
ok guys, I went through your github...help me find the printable files...where are they?

I did an article on "smart stethoscopes" a while back:


https://hackaday.com/2019/02/25/stethoscopes-electronics-and-artificial-intelligence/

HACKADAY DAN MALONEY

Stethoscopes, Electronics, And Artificial Intelligence

For all the advances in medical diagnostics made over the last two centuries of modern medicine, from the ability to peer deep inside the body with the help of superconducting magnets to harnessing the power of molecular biology, it seems strange that the enduring symbol of the medical profession is something as simple as the stethoscope.

Read this on Hackaday

Elias Jaffa12:16 PM
I'm also fellowship trained in emergency ultrasound, and have done some work with Glia related to an open-source solution for live-streaming ultrasound images: https://github.com/jaffamd/streambox

Elias Jaffa12:17 PM
@Dan Maloney Thanks for that . link, excited to take a look!

Tarek Loubani12:17 PM
@Tammo Heeren : I disagree that 'something is better than nothing'. Glia's goal is clinical equivalence. The third world is full of shitty handmedowns. We don't need to compromise the quality to reduce the cost on a 200 year old device!

But doesn't realyy seem suitable for austere conditions

Don Randolph12:17 PM
Do you find that cost is the major problem or delivery of the equipment to the desired location? Looking at the areas you mentioned, it would seem that the technology is there (we use a lot of medical equipment from Israel here), but the method used to get it to the patients might be difficult. I am a nurse anesthetist and we use electronic stethoscopes, but I have found that analog versions are just as good.

Israel Rosas12:17 PM
@Dan Maloney i'll be sure to check it out, thanks for the link

Thomas Shaddack12:17 PM
resin 3d printing, from uv-cured materials, can be much more accurate/precise. my recent experiments achieved 0.5mm pitch M12 thread (camera lens thread) holding well without need to chase it with a tap.

Tarek Loubani12:18 PM
@brian dolge: We thought about modeling and injecting the ear pieces. In the end, we aren't looking to make it 100% 3d printed. just accessible. So we opted to use headphone ear tips

Matteo Borri12:18 PM
makes sense they're easily findable

morgan12:18 PM
nice creative reuse

Tarek Loubani12:18 PM
@Thomas Shaddack : We're looking at how to incorporate SLA / mSLA, but the reality is that a rocket is easier to get into Gaza than a tub of resin would be. It'll be a while before that's a use case for us there.. We've been trying to figure it out.

Thomas Shaddack12:18 PM
what about silicone casting into 3d-printed moulds? this could be a low-cost way performing economical distributed manufacture down to one-off lot sizes.

Dr. Clint LeClair12:19 PM
to be candid, I print medical devices for our med ed sessions...the sterility was always an issue...fixed by fdm printing first, then lightly-brushing on resin and curing with UV to get a smooth, cleanable surface

Tammo Heeren12:19 PM
@Tarek Loubani Agreed. I was not talking about shitty hand-me-downs. Usually to achieve the last 5% costs a lot of time and money. This might not be necessary.

Jim12:19 PM
Just a note on electronic stethoscope, an ECM or MEMS device "hears" differently than the ear, so I believe some transform is required in order to have the electronic stethoscope sound like a conventional stethoscope

Thomas Shaddack12:19 PM
. o O ( what about loading the liquid resin into the rocket instead of the usual filling? )

Tarek Loubani12:20 PM
@Don Randolph : Great question. We're using tech as one component of our plan to solve a humanitarian issue.. As Gibson said, the future is already here. Just not very evenly distributed

Thomas Shaddack12:20 PM
just yesterday I stumbled over a self-sterilizing trick using crystal violet added to a latex paint. 1000 ppm of this and some light and the colony forming units fell down like post-election hopes.

Elias Jaffa12:20 PM
Huh

Elias Jaffa12:20 PM
Interesting...

Thomas Shaddack12:21 PM

https://discovery.ucl.ac.uk/id/eprint/1497078/1/Hwang_Final%20revised%20manuscript.pdf

UCL

Read this on Ucl

Tarek Loubani12:21 PM
@Thomas Shaddack : We have a model. That was Jennifer Glauche's initial idea and we ran with it in the prototypes. Just wasn't as easy to find silicon a and b in Gaza. We tried with construction silicone and those experiments failed.

Don Randolph12:21 PM
@Tarek Loubani How true.

Tarek Loubani12:21 PM
Very cool @Thomas Shaddack

Matteo Borri12:21 PM
what can be found easily?

Ryan Nibouar12:21 PM
In addition to the three new projects that the Glia team is currently working to develop, what other projects or ideas do you still see a big need for?

Thomas Shaddack12:21 PM
construction silicone does a lot of good job for me. if it failed, is it possible that there were factors that could be addressed?

brian dolge12:21 PM
On the tourniquet, I had a failure when I printed it in ABS, but succeeded with annealed(baked) PLA given that PLA is easier to print have you considered that route?

Tarek Loubani12:22 PM
@Thomas Shaddack : Earplug mold https://github.com/GliaX/Stethoscope/blob/e855c117cb89579a6fecc31196cdc0a91cd9c292/source_files/earplug_mold.scad

Jim12:22 PM
What is a bigger issue, the noise from the chest piece or external noise that enters around the ear plug?

Tarek Loubani12:22 PM
@Matteo Borri : Simple consumables and electronics.

Dr. Clint LeClair12:22 PM
@Tarek Loubani, was it the shrinkage during drying in the construction silicone, or what...we have multiple in-house tricks to get it to behave

Israel Rosas12:22 PM
@Tarek Loubani have you or your team ever think in something like a mesh of devices to solve the qualified people problem, like having a mesh of stethoscopes centralized and the a couple of trained people dedicated to id, does it sound like something that it could be useful

Tammo Heeren12:22 PM
So the idea is to have people print their own things?

Tarek Loubani12:22 PM
Anything that even resembles a construction supply or chemical supply is banned

Tarek Loubani12:23 PM
We don't have a whitelist or a black list, either. so you kind of have to guess and see

Marek Cermak12:23 PM
@Tarek Loubani May I ask Tarek, you wrote your goal is clinical equivalence. How do you want to prove it? by studies like you posted few minutes ago, or by some approval from 3rd sides like FDA clearence or CE mark, or something like that. Is it even possible?:)

Tarek Loubani12:23 PM
@Israel Rosas : That's a great idea. We're not thinking of that for a stethoscope. Gaza actually has lots of doctors (4000 of them), and auscultation is so specific to the context that it wouldn't help much. But with ECG, this is our plan.

Thomas Shaddack12:24 PM
re crystal violet (and my more favorite for disinfectant use, brilliant green, its sister triarylmethane with less annoying dye intensity), these are said to work even against MRSA bugs. i am trying to add it to printing resin and initial tests show it is soluble enough.

brainstorm12:24 PM
Do you have plans to tackle more complex equipment and its software? Would you hire professional reverse engineers for that or you reckon that the potential liability risk would be too high?

Dr. Clint LeClair12:25 PM
we've got a printable tongue blade we're nearly done with, if you want

Tarek Loubani12:25 PM
@Dr. Clint LeClair : I'd love to chat more about what you guys are doing. It was a combination of not being able to find the 2-part silicone, having irregular supplies fo construction silicone and just having a hard time controlling the conditions since electricity is VERY scarce

Tarek Loubani12:25 PM
@Marek Cermak : Yes, we certify our stuff via health canada, but we are currently working on CE. FDA is a distant goal because it's so expensive.

Tarek Loubani12:27 PM
@brainstorm: We want more complex gear, but we're years away from needing to do much serious reverse engineering. In the pipeline is a pulse oximeter, which is in the clinical calibration stage (then validation, then release). the ECG is awaiting ethics review for validation. the tourniquet is already in wide clinical use. And next up, my moby dick... Dialysis.

Thomas Shaddack12:27 PM
a trick i stumbled over is using superglue for glass (butyl cyanoacrylate) as a tissue glue. Loctite Super Attak Glass Bond has promising datasheet. check glass glue datasheets if they are real butyl CA or if they are methyl/ethyl with plasticizer as it is much less suitable. i read some study by some american docs that compared med-grade tissue glues with tech-grade CA ones and the result was that the latter can be used when in resource-limited settings.

anfractuosity12:27 PM
Sorry if this has already been answered you say 'having a hard time controlling the conditions since electricity is VERY scarce' do you take the 3D printer to Gaza/... , if electricity is a problem, do you use some kind of UPS for the printer?

Tarek Loubani12:27 PM
Dialysis is not an engineering problem. It's going to cost probably a hundred or two thousand dollars to engineer it. But the clinical testing will be hard and expensive.

Dr. Clint LeClair12:27 PM
I'd love to take a swing at Dialysis

Tarek Loubani12:27 PM
@anfractuosity : Solar and batteries. But climate controlling things is much harder than just printing.

Tarek Loubani12:28 PM
@Dr. Cl

Tarek Loubani12:28 PM
@Dr. Clint LeClair : Me too. Our goal is to make a generic one that can accept disposables from all suppliers.

Thomas Shaddack12:28 PM
as a potential patient i'd take my shot at a noncertified gear in comparison to having none.

Tarek Loubani12:28 PM
essentially breaking vendor lock in

Tarek Loubani12:28 PM
@Thomas Shaddack : That's seldom a real decision that's needed.

Atom Atom12:29 PM
How accessible are 3d printers and the needed materials for printing?

Thomas Shaddack12:29 PM
thought re climate control. phase-change materials, or leveraging nighttime when the solar energy influx is not there. basements also tend to be more stable in temperature than aboveground places.

Tarek Loubani12:29 PM
We had to do that for the stethoscope, and it weighed very heavily on me. It's tremendous responsibility. And our patients deserve better than for us to give them substandard care.

Willem Kolff did it with a washtub and a punch of cellophane sausage casing:


https://hackaday.com/2019/10/09/willem-kolffs-artificial-organs/

Tarek Loubani12:29 PM
@Thomas Shaddack : Great thoughts

Dr. Clint LeClair12:29 PM
"essentially breaking vendor lock in"...definitely game...gotten a few cease and desist's for doing this in Medical Simulation conferences on "hacks"! lol

Matteo Borri12:29 PM
i've tried to use mirrors to run a resin printer instead of the UV light

Matteo Borri12:29 PM
not worth doing power consumption wise

Matteo Borri12:30 PM
most 3d printing stuff can run off a car battery if it has to

@Matteo Borri - Mirrors as in reflecting sunlight to cure the resin?

Tarek Loubani12:30 PM
WE use OPzS batteries. Lithium+ batteries are essentially impossible to get there in the sizes required

Jim12:31 PM
It seems like there are already inexpensive pulse ox devices, is it a similar situation as the stethoscope, they just do not work?

Tarek Loubani12:31 PM
@Dr. Clint LeClair : Our legal strategy is pretty simple: We take expired patents and use them to create the device. The closer we can stay within the patent, the easier we can defend against some stupid lawsuit

Dr. Clint LeClair12:31 PM
"most 3d printing stuff can run off a car battery if it has to"...this is why I was always so interested in converting 3d printers to dc motor with encoder to reduce the load...making it easier to use in electricity-challenged areas, more sustainably...but alas, not my area of expertise

Tarek Loubani12:32 PM
@Jim: Correct. None of them are usable in regulated contexts. I bought a bunch and searched for the health canada / fda markings. Nope.

Tarek Loubani12:32 PM
Another thing, Jim, is that our pulse ox isn't just oxy / deoxy hemoglobin. We added carboxy (carbon monoxide poisoning mainly) and methemoglobin (various poisons and metabolic diseases), since the two extra LEDs cost just a few bucks.

Dr. Clint LeClair12:33 PM
@Tarek Loubani -totally get it and do the same for publicly presented material...its just presenting material vaguely usually gets the reps excitable

Thomas Shaddack12:33 PM
what are their wavelengths?

Jim12:33 PM
Okay makes sense small incremental cost

Tarek Loubani12:33 PM
Right now, the monopoly is held by Nellcor for the finger probes. Even GE uses nellcor probes in lots of their pulse ox's

anfractuosity12:33 PM
@Tarek Loubani that sounds really interesting, have you got a project page somewhere on the pulse oximeter, curious how it works

the_3d6 joined  the room.12:34 PM

Tarek Loubani12:34 PM
So by calibrating and releasing the data, we're going to be able to give researchers and other manufacturers the ability to make a finger probe of their own while knowing that it is calibrated

Tarek Loubani12:34 PM
I don't know yet, but I also suspect that nellcor's calibration data is almost all white-skinned people.

Thomas Shaddack12:34 PM
beware of many dyes. what looks like black or dark purple can have sharp fall in absorption when it comes to near-IR. a gotcha for anything like said oximeters.

Tammo Heeren12:34 PM
@Tarek Loubani So, what's the challenge with the stethoscope? I must have missed it.

Tarek Loubani12:34 PM
@Tammo Heeren : Challenge right now, you mean?

Thomas Shaddack12:34 PM
...or optical adapters.

Tammo Heeren12:35 PM
@Tarek Loubani Yes. What keeps you from using in where you want to use it?

Tarek Loubani12:35 PM
@Thomas Shaddack : Actually, we have to have ours dark otherwise we have problems. Our white pulse ox's were a problem.

FYI everyone, I'll post a transcript after the chat, in case you want to go back and grab a link.

Dr. Clint LeClair12:35 PM
why not swap the led and sensor in the cheap chinese pulse ox's and spend more time in finding a way to getting the data logged (onto a cell-phone, for instance)?

Tarek Loubani12:35 PM
@Tammo Heeren : Cost and military blockades in Gaza, cost in other places, remoteness in places like rural canada

Tarek Loubani12:36 PM
@Dr. Clint LeClair : But why? it costs $25 to make ours from scratch

Thomas Shaddack12:36 PM
there was even a problem with some trackballs/mice. unexplained failures at only a certain time of day. turned out the NIR went through the plastic when sun was shining into the office in a certain angle and overwhelmed the phototransistors on the rotation sensors.

Tammo Heeren12:36 PM
@Tarek Loubani So shipping stethoscopes to Gaza is not possible?

Tarek Loubani12:36 PM
Essentially impossible, though Israel would reply by saying medical devices aren't banned

Tarek Loubani12:36 PM
de facto, they are.

Tammo Heeren12:37 PM
@Tarek Loubani So your plan is to make them in Gaza.

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