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A Callout: Parts for an Iron Lung (hackaday.com)
69 points by JJLongusa on Nov 25, 2017 | hide | past | web | favorite | 23 comments

I read the gizmodo article when it came out and it really seems that the only reason these machines are still running is because the few remaining users have found technically-minded friends that can do the tinkering required to keep them running. I wondered at the time if there couldn't be some sort of crowd sourced effort to make replacement parts and help iron lung users find people to service their machines. But the liability associated with doing so seems to be enormous in my mind. I doubt good samaritan laws would protect someone in the slightest if they volunteered to service an iron lung, the user of the iron lung later died, and then the family decided to sue. One would hope that the family would understand the situation enough not to do so, be is there honestly any way to such a situation from happening?

If my grandmother used an iron lung I would absolutely do everything I personally could to keep it running, including servicing it and making replacement parts. But the thought of doing that for a stranger absolutely terrifies me.

The link out in the story to the Therac 25 that over irradiated and killed several people with a software bug seems to strengthen your point.


I'd heard of it before, but hadn't heard it was controlled by a PDP-11. Apparently running some bare metal ASM, not multics or unix (http://courses.cs.vt.edu/professionalism/Therac_25/Side_bar_...)

"It is clear from the AECL documentation on the modifications that the software allows concurrent access to shared memory, that there is no real synchronization aside from data stored in shared variables, and that the "test" and "set" for such variables are not indivisible operations. Race conditions resulting from this implementation of multitasking played an important part in the accidents."

To think all the reasons I ever disliked working with raw threads, could kill someone.

I know it was 1984 but if software did this today, the developers would be torn limb to limb as this is practically an interview problem.

As far as I can tell, this is only an effort to create new parts, not find volunteer service people. If there are zero available parts, it is better to have parts than to not have them. No replacement parts = guaranteed death at some point. So, the way to bet here is to support the creation of replacement parts.

If you don't create the parts, you don't get sued. If you create the parts and they fail, you do. Why take the risk for such a small market?

No one is requiring you to do this. Why do you care (aka object) if some folks actually give a damn?

Discussion of logistical details on Twitter:

https://twitter.com/RealSexyCyborg/status/933619850806620167 (Potentially NSFW as this is Naomi Wu, aka @RealSexyCyborg)

Conceptually these machines are simple. Seals, diaphragms, a few moving parts. Doesn't seem that it should be to difficult to fabricate parts that are no longer made by the original manufacturer.

There are more-modern negative pressure ventilators on the market.[1] I would think that from a legal perspective, it would be better to raise money to buy this woman a new ventilator, rather than subjecting her to cobbled-together replacement parts.

1. http://portalung.com/

Maybe the people who need iron longs require something with enough oomph rather than something small like that.

I still don't understand why these iron lung users can't switch to using positive pressure ventilators? The entire medical ventilator market uses positive pressure because it eliminates the need to surround the patient with costly pressure vessels, which dramatically improves the quality of life of the patient.

There are multiple articles readily found about complications of using positive pressure:




To my mind, this is actually related:


One of the problems you run into with any lung related mechanical devices is the need for proper sterilization. From what I gather, this is much less of an issue with negative pressure ventilation.

People in iron lungs are people with fundamentally compromised immune systems. Exposing them to germs forced into their lungs by positive pressure while potentially damaging their lung tissues in the process strikes me as a great way to give them a deadly infection, sooner or later.

Are you sure they are substantially immunocompromised? they're opening and closing their mouths and breathing through their noses on a regular basis while exposed to room air. There is no bacteria filtration like there would be with a properly configured positive pressure ventilator's circuit. The mucous membranes in the airway and nasal passages actually provide a significant amount of filtration themselves, and some circuit configurations are non-invasive which enables these natural filters to function.

There is potential for barotrauma in improperly configured devices, especially with volume-controlled ventilation, but it's possible to configure the device to ventilate safely, otherwise we wouldn't use them. Modern devices do have safety features like high pressure cutoffs and direct pressure controls which can prevent barotrauma. Some of these have to be configured correctly by the clinician for each patient.

Regarding the link to positive pressure HVAC, I'm not sure what that has to do with medical ventilation. HVAC provides a constant flow into a room, but medical ventilation cycles to an inspiratory pressure or inspiratory tidal volume repeatedly either on a patient trigger or on a set timing schedule.

I'm still really curious if there are any Respiratory Therapists or Physicians who can speak to this?

From what I understand, they are partially paralyzed. Every partially paralyzed individual I have personally met was pretty ill, basically. I have a compromised immune system. Being around paralysis victims is a big problem for me.

So, yes, I feel quite confident. Though what I know and what I can prove are very different things.

Edit: I will add that I have come to believe that breathing problems inherently impair the immune system. Oxygen is one of the things the body uses to kill stuff. If you can't breathe, you are pretty vulnerable to microscopic warfare. (Another thing I know but probably can't prove, fwiw.)

You find that paralyzed people are immunocompromised or harbor infections at a greater probability than the general population?

I wonder if this is due to lower rates of lymph circulation, which relies on the body being in motion. The lymphatic system is a key part of the immune system.

Yes, in my experience, they are chronically infected and it is dangerous for me to be around them.

I imagine there are quite a few factors, but I think that is a good thought. Walking a great deal -- sometimes on the order of many hours a day -- has played a large role in my successful efforts to improve my health. I am convinced that moving lymph is a very big part of that.

From the linked Gizmodo article (https://gizmodo.com/the-last-of-the-iron-lungs-1819079169):

> When Lillard is outside of the tank, she can breathe using a positive-pressure ventilator, a smaller device that pushes air into her lungs. But that instrument doesn’t provide the same relief as when she puts her entire body into the 640-pound, 7-and-a-half-foot-long apparatus. Plus forcing air into the lungs can cause inflammation or damage the air sacs.

The mechanics of the damage Polio causes to the nerves that operate the diaphragm means it is a tiring process to use a positive pressure ventilator.

With negative pressure the force is distributed over the entire body, with positive pressure it's forced right into ones lungs. Imagine lying on a bed of nails versus lying on a single nail.

Positive pressure ventilators can damage alveoli. They also can incubate bacteria and introduce infection.

You're right that the trade off in quality of life is one that many people think is worthwhile.

rubber gaskets are easy to manufacture if you have a mold for them. It's really awful that philips stopped making them without giving the mold to someone. With the mold, you can make a rubber gasket with nothing more than a kitchen stove and the raw materials.

> without giving the mold to someone

It's possible they could be called up to retrieve the specifications and possibly the mold. It's not necessarily the case that they've destroyed or lost track of them. Notwithstanding that, it's a vacuum vessel, there are only so many ways the gasket could be designed. I'm not qualified to design a part like that, but surely there are many people who are.

What rubber gasket are you referring to? I don't recall gaskets specifically mentioned in the article. They talk about they neck collar, but that is supposedly "canvas."

Due to the mergers/acquisitions involved over the years, it's entirely possible that Philips doesn't even know exactly where their current stock came from. While I certainly believe they could be of more help than they have been, I also think people are massively underestimating how hard it might be for them to do so.

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