Dan Maloney
@profdc9 negative pressure on the chest? That's interesting. I looked into that, but I couldn't find enough peer reviewed medical sources to justify a prototype. If these guys are finding it works and are going to trials, that's amazing.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5131805/
Ventilator-Induced Lung Injury
As with most medical and pharmacological interventions, mechanical ventilation must be titrated within a therapeutic window, providing the required life-sustaining support while minimizing unintended toxicity. The potential for mechanical ventilation to cause harm was first described in the mid-18 th century.
Read this on PubMed Central (PMC)
higher wattage, less time to sterelise the area
They tried that 20 years ago, now they favor PEEP (positive expiratory end pressure)
@Josh Starnes , according to the feedback that you have received, what is the main target that your lamp is used to disinfect?
@profdc9 - Good question, don't know. I also wonder about PEEP - how does an iron lung manage that? Or does it need to? I know that people who got polio in the 1950s are still in the 40s-era iron lungs, and that tech predates knowledge of PEEP, I think.
@profdc9 If you're applying pressure externally, like in what you have linked, the chest muscles will be doing their job to prevent barotrauma. They will, however, also prevent your system from WORKING in some cases. The amount of vacuum will vary per patient.
and don't forget, power diminishes by the square of the distance
(by the way, very appealing design)
doorknobs, dishes, handles, masks. things that are handled often
@Josh Starnes - Groceries that you bring home...
yes, bugs are killed in a couple seconds 1-2 cm away, at a few inches 10-15 seconds
@Josh Starnes I tried to use my old UV exposer to "clean" some FFP2 masks
Then I have found an article to which the International Medical Center of Beijing contributed:
https://mp.weixin.qq.com/s/3QYVWO4kj5qwuSHnhcM9uQ
UVC sterilization is coered in a very accessible way by the Scottish electronicist Big Clive
https://www.youtube.com/results?search_query=big+clive+uv+light
the band I am using is reffered to as Far UVC, 154-155 nm , NON ozone creating bulbs
.....HEPA filters are also good materials for masks, and they can be disinfected by boiling in water ( https://en.wikipedia.org/wiki/HEPA )
A quick look at the research does not make it obvious to me that negative pressure avoids the problem with ARDS that positive pressure does. Both might have a narrow therapeutic window.
https://www.youtube.com/watch?v=2T39BHvrHZ0
Keep in mind a lot of mask+shield designs incorporate foam materials for comfort or to conform to facial topology. The group I've been working with rejects anything with foam as it can't be sterilized OR considers it as 1-time-use disposable.
I put a germicidal lamp into a cardboard box lined with aluminum foil to maximize available dose. Aluminum has a high reflectivity for UVC.
However it is preferred to use a new filter, and not the filter already inside your vacuum cleaner. HEPA and UV lamps may be a good sollution for DIY filters
I payed (a lot) extra for Silicone weather stripping to avoid foam on the masks I'm printing.
Or paid.
sous vide is a very easy constant temperature source. and you can easily go with the dry heat or moist heat depending on which research papers you read.
I think a pulmonologist needs to weigh in about the possibility about ARDS with an iron lung.
@James Newton is it a solid material? Sounds good if it can be wiped down with alcohol.
I suggest using incandescent lamps for heating because of their low temperature.
For ongoing therapy, Canada has a grant open for monitoring devices:
https://www.ic.gc.ca/eic/site/101.nsf/eng/00078.html
.....also about masks: three weeks ago I built a respiratory filter out of an old MIG-19 aircraft pilot face mask, a hose from my old car in the cooling system, two other hoses we call "elephant nose" and two military anti-biologic warfare filters
That grant has some stiff requirements.
Sous vide cookers are intended to work in a water bath, so the PPE must be placed in a plastic bag that keeps it dry. The charged layer on PPE is destroyed by excessive moisture.
Looks like it's pressing the glasses into his face. Ouch!
yes definitely; use the sous vide cooker for your mask just like you would for food
And bad seal too, I'd think
Riley.august, can you link me to a summary of your work on PPE ?
One thing that I have received the feedback to be useful for home care is pulse oximeter. It is used as a control for people being treated at home.
Whenever the oxigen level drops below a certain threshold, that triggers the hospitalization
if you want moist heat (some research papers with SARS-CoV-1 suggest it's better) you can spray a bit of water in the bag with the mask
FYI, I'll pull a transcript when we're done so all the links are preserved
it's my face.... and it's not pressing the glasses. Works fine. Cops always stop me for sharing the design.
But as long as people can be mantained at home, the pressure to healthcare system is lower
The Canadian grant solicitation is crazy, but not out-of-bounds crazy. SpO2 and pulse oximeters are already pretty cheap. Adding Wifi to it couldn't be that hard (ESP8266/ESP32). Adding a pressure cuff might blow the budget though, because a pump would be needed.
This is a good sollution for Eastern Europe hackers who have access to old Soviet Union gear since the post-war occupation...
@borelli.g92 - Good point. THey're so cheap now that every home should have one in their med kit.
@[skaarj] - and it's an awesome look for around town ;-)
154-155 nm is vacuum UV, the air absorbs it. UVC 254 nm is generated by mercury vapor and causes thymine dimerization which prevents virus replication.
@Dan Maloney thanks, I have received that feedback from some friends who are donating a small sum to hospitals in my area (northern Italy)
You can get breakout modules for some MAxim part, I think, to implement a pulse oximeter for a few pounds. By the time you added your own OLED you might as well buy a complete unit.
But you could put the mondul online. Or nixies :)
@Dan Maloney ...two months ago if I wear that around town, people would call the nearest mental asylum to come and catch me. Now they want to take pictures of me.
tinfoil hats seem so in vogue now.
@[skaarj] - Everything changed so fast, right?
@profdc9 sorry I meant 254-255, not feeling great today, it was a typo
that's ok, this is getting on everyone's nerves after awhile
Well... 'preppers' were always regarded as weird people. Now things changed...
far UVC (207–222 nm) is interesting as it can kill airborne bacteria and viruses, but doesn't harm our skin and eyes
Tell me about it...
I had a bunch of N95 masks stockpiled. I gave it to the local hospital.
@skot citation needed.
https://www.nature.com/articles/s41598-018-21058-w
SCIENTIFIC REPORTS
DAVID WELCH
Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases
Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic.
Read this on Scientific Reports
An interesting question: do high-voltage air purifiers have any benefit in cleaning air from organic particles such as 'covid'?
Anyways. I know a pulmonologist. Perhaps I can get him to answer a few questions about iron lungs. As you might guess though, they have their attention spread pretty thin.
it probably won't work with SARS-CoV-2 as it's usually transmitted in droplets
@profdc9 Is baseline pressure above ambient required to measure systolic and diastolic BP? I'm not aware of anything other than the cuff, but wondering if anyone's heard of anything in that regard.
I think the issue is that with the cuff, you need to inflate it, which needs a motor capable of a certain amount of pressure.
I would not suppose I could make a pressure cuff cheaper than the one I Could buy at the pharmacy.
@Dustin Sysko There are such non-cuff devices but they are undergoing validation e.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873623/ There are also pulse oximetry device that experimentally are used to derive measures of BP
Building a true ventilator with sensors to get pressure,temp and hydro. automatic breath system
For example, I see some blood pressure cuffs for 35 USD on amazon. They could be communicated with my a ESP32 with bluetooth.
e.g., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1717578/
re. UV - https://www.bbc.com/future/article/20200327-can-you-kill-coronavirus-with-uv-light
“You would literally be frying people,” says Dan Arnold, laughing in disbelief.
So for example, about 45 USD for pulse oximeter + 35 USD for blood pressure cuff with bluetooth + ESP32 (6 to 10 USD), provides a wireless solution for monitoring a patient. Cheap by an medical device standard but still over the budget of the Canadian solicitation.
@DrG That's super interesting. Thanks.
Cheapest sphygmomanometer I found was ~$19 CAD
https://www.walmart.ca/en/ip/LCD-Display-Blood-Pressure-Monitor-Wrist-Pulse-Meter-Automatic-Digital-Pulsometer-Sphygmomanometer-Family-Diagnostic-tool/PRD6XBNIAMDGGW7
If these have TTL serial it is plausible they could be integrated into a wireless device.
My question is how important cost is at this time. Even if each unit costs $100 per patient, compared to the cost of patient treatment, its nothing.
I think it's important to remember that with all the things we're talking about here that are patient-directed, like diagnostics and therapeutics, we have to be really careful. Ideas are one thing, but building some of this stuff could be really dangerous. We all should proceed with caution.
This is true, but monitoring a patient has less risk than therapeutics.
Absolutely, but you still want to make sure you're getting the right numbers, so the correct decisions can be made.
@Dan Maloney AGREED and morover building any kind of medical advice without consultation with medical professionsals is also dangerous. The strength of great EE minds (as with all other fields) is to collaborate so that the sum SME is great.
Dan is right, of course, but being an embedded sensor / logging guy, I would love to try sensing the ntake and helping after that.
@DrG - Well put! We're better when we team up with those that can cover our weak spots. The lone wolf inventor model doesn't work for things like this.
We are talking about interventions that, in order to have any impact on patient health, must be deployed quickly and use available resources. The unquantifiable risk of inaction is balanced against the known consequences of deleterious action. If we simply value the knowable above the unknowable, then we are paralyzed into inaction.
@profdc9 @Dan Maloney I agree with what you're saying. A small team can bring up and answer more questions than an individual. I do remote sensing prototyping, but I'm no medical professional!
@James Newton Come on over to #VISP - Ventilator Inline Sensor Package
if we can get RTs and physicians to join these chats that wuld be great
@profdc9 yes, but first do no harm. Seeking consultation with medical professionals is not difficult. You design a UV sterilizer - do you not want to know how UV light MIGHT harm? Of course you do. Medical people WANT help. They want all the help that they can get.
The BC solicitation justifies their low unit cost by saying it would be related to making it available in quantity to the widest range of medical facilities. I'm assuming the budget for some remote areas is low.
Trying to find medical advisors but it has been slow going
any advice is appreciated
on how to connect
Hi, I am ventilator dependent so all these topics interest me.
So, maybe in the last few minutes we can swivel a bit: how about hacks that everyone is using to keep sane and safe in isolation?
@luther Make contact with your local university - med school, public health school and so on. Many will be happy to talk with you and discuss challenges and so forth. You don't have to start with talking to the surgeon.
@luther Here in BC the medical guys seem to like to work with someone from the engineering community as a translator/information broker.
Unfortunately there's no authority and scant legal precedent to guide what is ethical, legal, and moral behavior in such a circumstance. I am fairly sure, however, that after the pandemic is over, the legal repercussions will be extreme and could likely dissuade further interventions. There is no risk in not doing anything. The only exception to this are the doctors who are more or less required to risk their health to save patients. The ones that object to the situation of not being sufficiently protected find themselves suspended or terminated.
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