Naked Science Forum
Life Sciences => Physiology & Medicine => COVID-19 => Topic started by: chiralSPO on 15/03/2020 19:30:01
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I recently read an article that said that oxygen generators are in short supply in some places.
( http://www.cidrap.umn.edu/news-perspective/2020/03/global-covid-19-cases-pass-100000-mark )
Is this going to be a worry in most places as they become inundated with patients, or is it really just some particularly isolated locations?
How bad does it have to get for a hospital in the US to accept non-medically rated oxygen generators (provided the oxygen produced can be proven to be of sufficient purity/safety)?
My lab studies electrochemical oxygen generation. I know it's not as energy efficient as pressure swing oxygen concentrators, but we can generate arbitrarily large volumes of oxygen per second with minimal capital expenditure (and no moving parts!) compared to what I see medical oxygen concentrators going for...
Inspired by academic biochemical labs that have risen to the occasion and offered their expertise in running tests, I wonder, "is there anything a lowly chemist can do?" Or should I just start selling off our solvents as disinfectant?
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There are commercial liquid gas companies that supply a variety of industries with gas by the ton (or tonne, if you prefer).
- I am sure that they could divert a few tons from established customers, introduce enhanced processes (eg some more testing), and provide ample quantity.
- I am sure there will be issues about delivering it at the right temperature and pressure, through the right hose diameter and connector thread, but I'm sure these could be resolved
- Their raw material is the air, which is delivered right to their plant
Organising reliable delivery of a few tons of raw material to your lab may be more of a logistical problem...
But by all means, offer your services!
A typical medical oxygen product specification (other vendors are available): https://www.boc-healthcare.com.au/en/images/Product%20Information%20Compressed%20Oxygen_tcm350-72338.pdf
The other problem is the ventilators to deliver the oxygen to those who need it most.
- The worst-affected patients may need oxygenation which completely bypasses their lungs, an ECMO machine
- Apparently, prices can range from $10,000 to $50,000
- And they are suddenly in high demand (or soon will be)
See: https://en.wikipedia.org/wiki/Extracorporeal_membrane_oxygenation
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Thanks evan_au!
This may well just be a task to feel productive, but it does feel nice to work with purpose during these trying times!
I may update this thread with some of my findings :-)
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https://www.directhomemedical.com/cart/merchant.mvc?Screen=PROD&Product_Code=everflo-q-oxygen-concentrator-philips-respironics&Store_Code=DHM&gclid=EAIaIQobChMI6p_nq-me6AIVaYVaBR3gkgp2EAQYAiABEgJFOfD_BwE
For a point of reference, a personal oxygen concentrator (~$1000) is able to provide up to 5 liters of oxygen per minute (it's only 95% pure, presumably with the balance being nitrogen, because it is concentrating air--electrochemical oxygen production would result in a higher purity because no separation is required--the only major impurity would be water vapor, about 2% if saturated, which I understand is a good thing for direct delivery, but not ideal if it is t be stored.)
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Not sure whether many (or any) hospitals are equipped to deal with liquid oxygen: adding frostbite and general conflagration to intensive care will only aggravate the problem.
Personal oxygen concentrators at 5 l/min should be more than sufficient as this would double the oxygen availability to a healthy adult and provide a significant excess over that to a resting elder.
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If there are a lot of people off sick at the local steelworks (or whatever) there will be plenty of oxygen going "spare".
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https://www.nytimes.com/2020/03/18/business/coronavirus-ventilator-shortage.html?action=click&module=Top%20Stories&pgtype=Homepage
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After doing much research (and a little experimentation) it seems that oxygen concentration from the air is MUCH more energy efficient and less capital intensive. With adequate filtration and humidification, pressure-swing systems seem like the way to go. For example, a system like this: https://www.oxidationtech.com/og50.html can supply enough oxygen for ten people, and goes for about $6k. There are also. plenty of systems that can supply enough oxygen for hundreds (or thousands), but the prices are not listed, and I don't know how quickly they can be set up.
That said, it seems that non-invasive ventilators are not particularly good at improving outcomes (and if I read this correctly, most who get the invasive ventilators die anyway)
https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30110-7/fulltext
However, it also appears that a major concern of this lancet paper is that caregivers are at increased risk due to aerosol generation.
(At the risk of acting like a hammer and viewing all problems as nails), I wonder about the utility of an electrolyzer to generate oxygen for people, and hydrogen for use in an in-line incinerator to sterilize the exhaust, like so:

schematic4.png (286.75 kB . 3308x1304 - viewed 3861 times)
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I think it is the amount of oxygen in the ward or coming through a respirator, the other gasses, mainly argon and some CO2 (from an oxygen concentrator) are not a problem. I don't think purity is an issue.