
A Callout: Parts for an Iron Lung - JJLongusa
https://hackaday.com/2017/11/25/a-callout-parts-for-an-iron-lung/
======
pitaa
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.

~~~
tyingq
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.

[https://hackaday.com/2015/10/26/killed-by-a-machine-the-
ther...](https://hackaday.com/2015/10/26/killed-by-a-machine-the-therac-25/)

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_...](http://courses.cs.vt.edu/professionalism/Therac_25/Side_bar_1.html))

~~~
ashleyn
"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.

------
Mz
Discussion of logistical details on Twitter:

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

------
ams6110
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.

------
mrestko
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/](http://portalung.com/)

~~~
Something1234
Maybe the people who need iron longs require something with enough oomph
rather than something small like that.

------
jschwartzi
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.

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

[https://www.medscape.com/viewarticle/581344_7](https://www.medscape.com/viewarticle/581344_7)

[http://www.mdedge.com/ecardiologynews/dsm/5224/hospital-
medi...](http://www.mdedge.com/ecardiologynews/dsm/5224/hospital-
medicine/complications-mechanical-ventilation)

[https://www.ncbi.nlm.nih.gov/pubmed/2199002](https://www.ncbi.nlm.nih.gov/pubmed/2199002)

To my mind, this is actually related:

[https://www.energyvanguard.com/blog/54084/Why-I-m-Not-a-
Fan-...](https://www.energyvanguard.com/blog/54084/Why-I-m-Not-a-Fan-of-
Positive-Pressure-Mechanical-Ventilation)

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.

~~~
jschwartzi
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?

~~~
Mz
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.)

~~~
echelon
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.

~~~
Mz
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.

------
timthelion
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.

~~~
microcolonel
> _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.

