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Seems like this is a downside of single-use sterile medical parts. In most cases its much easier and safer to just grab a new single use part but in times of sh
by s0rce 7y ago
Seems like this is a downside of single-use sterile medical parts. In most cases its much easier and safer to just grab a new single use part but in times of shortage you could sanitize and sterilize multiple use metal parts in house and get them back in use without needing to physically manufacturer more locally, which often isn't practical - even with additive manufacturing.
- Camillo 7y agoThis article could make one more concerned about that problem just by making them aware of it. But if you were previously concerned about it, this news should reassure you, since now you know that there is a solution available even in crisis conditions.
- s0rce 7y agoOnly for parts amenable to 3D printing, which is limited at the current state of technology.
- JMTQp8lwXL 7y agoDepends on the nature of the contamination. Some pathogens are exceptionally difficult to de-contaminate, like Candida auris.
- adrianN 7y agoThere aren't many things that survive high pressure autoclaving. Prions are the only possible concern that I'm aware of.
- supandi 7y agoGood point
- bonestamp2 7y agoFrom what I understand, there are some components that can't be put in an autoclave and/or have areas that aren't well suited to autoclaving. So it may not be a one-size fits all solution.
- bravo22 7y agoThe cost and complexity of making parts that can survive autoclave is a big driver of single use parts.
- russdill 7y agoAsteroid organic sample return missions actually face some of the same problems. Even moderately complex sample retrieve mechanisms can't be autoclaved. That's why so many are using passive sample collection bins and compressed gas.
- pauljurczak 7y agoIs it really necessary to use a sterile valve for a new patient affected by the same strain of virus. I would expect the hospital to reuse a valve, instead of letting a patient die without the ventilator.
- sb8244 7y agoWould there be risk of contamination from other diseases that patients may have? I agree with your general expectation that risky reuse over high-probability death seems strongly preferable. One tricky moral dilemma is what to do if you have 1 clean valve, 1 dirty valve, and 2 patients.
- endtime 7y agoTriage as you would anyway (same prioritization), or flip a coin.
- thaumasiotes 7y ago> One tricky moral dilemma is what to do if you have 1 clean valve, 1 dirty valve, and 2 patients. Why would this be trickier than having 1 clean valve, 0 dirty valves, and 2 patients?
- OJFord 7y agoWell it's exactly the same after you make the choice/use the first valve.
- pauljurczak 7y ago> what to do if you have 1 clean valve, 1 dirty valve, and 2 patients "Just received word from an ICU doctor at a small NY hospital: They are officially out of ventilators and are now double venting patients with COVID (using the same ventilator for 2 infected patients)."
- sb8244 7y agoAbsolutely insane. It's barely started.
- Svip 7y agoIt's not to protect the patient (well also that), it's to protect the doctors. My granddad was a medical student back when they still reused syringes. That gave him a liver infection, so he could not donate blood his entire life. One doctor can save numerous lives. Putting one out of commission is a huge blow in a crisis.
- wwweston 7y agoI agree with the values you're describing here, but it's still not clear to me that a re-use workflow needs to be that different from single-use. Presumably the single-use involves tossing used pieces into a biohazard disposal container to be removed later. What's the issue with tossing the same material into a biohazard container of things to be solution-rinsed autoclaved and/or UVd the hell out of, then maybe wrapped or banded so that it's clear they're clean? Maybe it's a labor/scale issue?
- Svip 7y agoLabour/scale, indeed. The facilities where these things are usually produced have the capacity to make sure they are sterile. Hospitals cannot sterilise items to the same scale. You just need to be careless once for it to be a problem. And considering how many sterile items you need to use every day - particularly in an emergency - it is not unlikely that one item went back into the reuse cycle without being sterilised. It's to avoid the question, 'was this item sterilised?' If its wrapper is open, assume it is used. You can only do that safely with single-use items.
- richmarr 7y ago> If its wrapper is open, assume it is used. You can only do that safely with single-use items. How about putting the re-usable item in a wrapper so that the same rule can apply.
- killjoywashere 7y agoAll surgical steel is reused exactly this way. There are plenty of plastics that get autoclaved as well.
- Neil44 7y agoYes the issue is the stability of the plastic at the temperature and pressures that sterilisation needs. I know that plastics have been developed for exactly this purpose but I don’t think they’re very widespread yet.
- regularfry 7y agoGiven the temperature constraints, I can imagine exactly those plastics are fairly unlikely to be suited to the traditional extrusion heads on common-or-garden 3d printers.
- Neil44 7y agoYes I would think moulding would be the way. One of my clients is a plastics company and I saw a presentation on it a little while back. The new plastic versions of things can be non-disposable but still much cheaper and lighter than metal versions.
- kragen 7y agoIt appears from Wikipedia that normally you sterilize things at 121° in steam for 15–20 minutes? If that's the case, common plastics like nylon and polydimethylsiloxane should be okay, although poly(lactic acid), commonly used in FDM 3-D printing, and poly(ethylene terephthalate) won't be.
- neltnerb 7y agoA lot of plastics will deform when autoclaving. There are enough lists for autoclave compatibility that I forget the answers, but this looks like a pretty complete chart. https://www.industrialspec.com/resources/plastics-sterilization-compatibility https://www.industrialspec.com/resources/plastics-sterilizat...
- kragen 7y agoThis is a really comprehensive table! It lists PLA as "Poly(L-lactide)", giving it a surprisingly good "Fair" grade for autoclaving, and polydimethylsiloxane as "Silicones", rating them "Good". It also lists polycaprolactone, which melts around 70° and can be easily molded by hand while molten, as "Fair". Surprisingly, though (to me), it lists nylon (6 and 6-6) and teflon (polytetrafluoroethylene) as only "Fair", like PLA and PCL, even though at least teflon is totally insensitive to water and commonly used with service temperatures up to 260° (among other things, in FDM printer hotends). So I wonder if this table might have some significant errors in it? Maybe someone interchanged some plastics without intending to. It can't possibly be correct to put PTFE and PCL in the same category, can it? Anyway, common plastics it rates as "Good" for autoclaving include acetal (Delrin), polypropylene, silicones, and (for some definitions of "common") PEEK. Surprisingly polyimide (Kapton), the favorite high-temperature chemically-inert plastic of aerospace and electronics, isn't in the table at all.
- usrusr 7y agoThe defense in depth mindset response would be single use where it is superior, but with emergency protocols for reuse in emergencies where perfect becomes the enemy of good. E.g. rate disposable items for heat treatability even if nobody will try to disinfect them outside of an emergency shortage.
- saurik 7y agoYou could alternatively just have a couple reusable items on hand per machine instead of making every single disposable one reusable.
- usrusr 7y agoEven better! Seal them in a box labeled "break glass in emergency" if capitalism is the main objection.
- LorenPechtel 7y agoYeah, that would be my recommendation. Make a supply of parts that can take the autoclave and keep them around for emergencies. If you had to use them because you messed up the supply chain (didn't order enough), big fine. If you ordered but the supplier couldn't deliver, no fine.
- callmeal 7y ago>in times of shortage you could sanitize and sterilize multiple use metal parts in house Got one word for you: prions. Standard sanitization procedures do not work with them, and if the hospital is not setup to decontaminate for prions, they're unlikely to be able to to it during the crisis. see https://www.memphis.edu/ehs/pdfs/deconprions.pdf https://www.memphis.edu/ehs/pdfs/deconprions.pdf for what it takes.
- swebs 7y ago>Autoclave at 132 C for 4.5 hours All hospitals should have autoclaves, shouldn't they?
- neltnerb 7y agoEvery biology adjacent facility I've ever heard of requires them for at a minimum biohazard waste disposal. I don't know how a hospital could not have enough given that all those plastic one time use parts still get autoclaved after disposal. In terms of overall mass, sterilizing all those parts should be equivalent to throwing them away. It would require different internal procedures though, I don't think people are used to saving and reusing things. And it would be more labor intensive. And autoclaving might destroy the parts. Most of which seem like reasonable tradeoffs in an emergency.
- pnutjam 7y agoNot everything can go in autoclaves: https://www.denverpost.com/2019/06/16/porter-hospital-infections-surgical-sterilization-lawsuit/ https://www.denverpost.com/2019/06/16/porter-hospital-infect...
- elric 7y agoI'll add Candida Auris to the list of scary things that are hard to kill in hospitals: https://en.wikipedia.org/wiki/Candida_auris https://en.wikipedia.org/wiki/Candida_auris
- MPSimmons 7y agoThat is a valid argument for neurological equipment, which has the highest liklihood of infection for prions, but during this pandemic, the likelihood of prion transmission is very remote, probably to the point that it approaches zero, and is probably zero for these valves.