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Comment by mentos | Hacker News Reader

Separate thought, if you were to replace your lungs with a machine that oxygenated your blood, could you calmly sit without breathing? Is the anxiety/impulse to breathe do to a lack of oxygen?

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It's due to the buildup of carbon dioxide.

https://en.wikipedia.org/wiki/Respiratory_center

This oxygenator[1] along with a load of other kit and gas supplies replaces your lung function during a heart bypass. It swaps O2 and CO2. But it only works for hours before clots start to become a problem. The fibres in the oxygenator are coated with heparin to delay the complications.

[1] http://www.medtronic.com/affinity/

edit: forgot the link!

You could fill them with a oxygen providing fluid?

https://en.wikipedia.org/wiki/Liquid_breathing

Yes, you could sit without breathing. They do this in surgery all the time (heart/lung machine).

I suspect they want to minimize the blood's contact with anything because blood likes to clot, so doing it longterm without blood thinners might not work so well.

That's what is so amazing about this device: All other devices before it threw off so many clots they killed the patient rapidly.

Lookup "Jarvik" for some of the history.

It's from buildup of co2. You would need to scrub that.

In particular, in an environment that has insufficient oxygen in the air but that doesn't have carbon dioxide, you don't feel a desperate need to breathe; you just pass out and die.

This can and does kill people, in a variety of low oxygen situations. E.g. labs with liquid nitrogen freezers are mostly now fitted with O2 alarms to warn occupants about a dangerous and undetectable low O2 situation. Since you're still able to expel CO2, you literally won't feel anything wrong until you just collapse and quietly asphyxiate. Movies get this wrong all the time, and it bugs the heck out of my biotech friends with safety training with aforementioned labs.

But at least it's a totally painless and stress free way to die.

Your body will prompt you to breath when either CO2 levels are too high or O2 levels are too low. In your example the subject is still breathing even if he isn't getting O2.

One problem ER docs see periodically is the CO2 "sensor" can become broken in patients with chronically high blood CO2 levels, i.e. people with certain types of COPD. They only breath when their blood O2 levels are low, and if you give them oxygen they just stop breathing.

This is not true; just about any relatively non-toxic inert gas other than CO2 can take the place of oxygen without any significant response.

We do have a hypoxic respiratory drive, but it is exceptionally weak, and unconsciousness will occur before any noticable distress is noted.

The hypercapnia alarm response we're all familiar with is tied to carbon dioxide levels, not oxygen.

What's not true? That he's not breathing?

Hence the recommended method of life exit for people with terminal illness is to use a hood connected to Helium. Of course you need some "assistants" to remove the evidence since most places assisted suicide is illegal.

I guess one thing to look out for is the smell of rotten eggs in a server room. From what i understand that is a sign that the UPS batteries are venting hydrogen sulfide.

That or sulfur dioxide, yeah. I've smelled the latter in an office that doubled as a data center, when one of the UPSs' charge regulation circuit went wonky and overdrove its batteries.

That's probably not a major asphyxiation risk unless you're trapped in a room with it, though, because, unlike inert gases like helium or nitrogen, sulfur compounds are irritating as hell - a UPS boiling its batteries will send you fleeing for the nearest source of fresh air, with eyes and nose streaming, before it'll suffocate you.

Excuse the morbidity, but if this type of asphyxiation is essentially pain and stress free, would it not be a humane method for euthanasia or even for capital punishment?

Yes it would.

Yes. It's been approved for capital punishment in the US state of Oklahoma:

http://www.newyorker.com/news/news-desk/how-oklahoma-came-to...

Also search for “exit bag”. You’ll find instructional images, as well as an instructional video made for the sick and elderly, about using this technique to commit suicide.

It sure would. If I had to be executed and could choose my method, I would choose this.

I don't know why it's not universally used. I suppose it's some combination of tradition and a belief that executed criminals should suffer.

This is inert gas asphyxiation [1].

CO2 buildup is what drives the panicked "I can't breathe" response. If there's no CO2 buildup and no oxygen, it's a rapid and apparently peaceful lights out.

[1] https://en.wikipedia.org/wiki/Inert_gas_asphyxiation

How many organs can you do this for? Heart, lungs, kidneys at least. 'Brain-in-a-jar' seems like the most achievable form of immortality at the moment.

Our bodies are more complex than we can design for yet. Most organ replicating machines will start to fail after a couple of hours due to complications like clots. The heart is probably the simplest due to it's very simple function. We also have kidneys mostly working. But everything else is still problematic.

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