What I mean is I have been told that the desperate need to breathe when trying to hold your breath is triggered not by your body sensing a lack of oxygen but rather its reaction to a buildup of carbon dioxide. Is this true?
If so, if I walked into a room filled with nitrogen or helium or whatever, I would feel normal for 3 minutes or so then just go black? Since respirating nitrogen would not have co2 as the waste product the trigger in my brain wouldn’t register the pain as in holding my breath?
It is not just possible to pass out - this is now the in way to commit suicide.
All the stuff I’ve read suggests it is the CO2 thing. You feel no pain or struggling or desire to breath. Some people (who haven’t gone through it all the way [some wake up with the bag pulled off of them - apparently in a semi conscious attempt to save themselves]) report a sense of not feeling like their lungs were filling up normally, but there is no pain generally reported.
You almost certainly would not notice it - unless you were working in an area where this might occur to you this is happening. If you just stumble into an airtight room filled with helium, nitrogen, or argon - you will probably black out in way less than 3 minutes. Some people are almost dead by then.
Hypoxic atmospheres have been used as a method of animal slaughter in animals such as chickens, where it is known as controlled atmosphere killing.
An occasional cause of accidental death in humans, inert gas asphyxiation has been used as a suicide method, and has been advocated by proponents of euthanasia (using helium or nitrogen in a device called a suicide bag). Nitrogen asphyxiation has been suggested as a more humane way to carry out capital punishment, but so far this use of inert gas has not been attempted by any country, state or territory.
I don’t know about the medical side of it, but I know from working in breweries that CO2 from carbonating the beer will settle into pits and becomes a suffocation hazard. A co-worker was doing work in one of these pits and almost passed out. He never felt a need to breathe.
Note that it probably wasn’t even close to pure CO2 in the pit. It was just a CO2 leak nearby that dropped enough CO2 to lower the oxygen content in the air to the point where it was a suffocation hazard (not all that uncommon in breweries).
I also know that both helium and sulfur hexafluoride will cause you to pass out before you feel any need to breathe. Sulfur hexafluoride is slightly more dangerous than helium since it’s heavier than air and therefore will happily stay in your lungs if you don’t breathe deeply to force it out. (for those who aren’t aware, helium, since it is much lighter than air, makes your voice high and squeaky, which most folks know, and sulfur hexafluoride, which is heavier than air, makes your voice very deep so that you sound like Darth Vader - great fun at parties, assuming you don’t pass out and die)
There has actually been research done on this in Switzerland - where four people were monitored as they killed themselves with helium - all were unconscious in under a minute and most dead in under ten. One showed signs of life for 42 minutes. Original study is now behind paywall, but it didn’t use to be. Here is a copy as I remember it:
The general feeling seems to be the 42 minutes was due to a poor fitting face mask - and that if you were to enter a truly sealed room of helium - and had exhaled before entering - you’d lose consciousness in 5-10 seconds (I don’t get this, but have seen it several times - I don’t see why this isn’t at. Least a minute) - and you’d be dead in 3-5 minutes.
Best practices include using an oven bag with tubes from two helium (or other inert gases) tanks with a regulator. Plenty of people have “survived” this method based on reports on suicide project, but there are doubts to some of their technical skills. It is considered more lethal/foolproof than any oral drug combination when done correctly.
I’m surprised it hasn’t picked up more traction. It’s been pretty known for about a decade, but I know at least two psychiatrists who have never heard of it. I guess it will take someone famous to make it more popular. It does take a little bit of effort, so there is that going against it.
Anyway - be careful if your job requires it - but if you are walking into a room fast enough, by the time you realize it - you’ll never make it back out. Luckily the chances of walking into an airtight helium filled room are pretty small.
While Helium-filled rooms are a rarity, Nitrogen is often used as an inert atmosphere in industrial facilities, and the risk of entering such a room is somewhat higher, and people can die very quickly.
Most biological research facilities and, I suspect, hospitals have large rooms of liquid nitrogen cooled containers for cryo storage. These can also prove deadly if they are not properly ventilated or if a nitrogen tank springs a leak. There should always be an oxygen monitor placed inside the room so a worker can at least see that oxygen levels are in the danger zone.
Uh, why don’t we use this as a method of capital punishment?
It sounds quick, painless, and there’s not the pain of jabbing a massive needle into someone’s vein, or the burning sensation as the drugs are injected.
Also, perhaps more importantly, it does not sound like it would need a person with any medical training whatsoever to administer it.
Not only is the risk higher (I’ve worked at steel mills) they give specific safety meetings about it. One point they are very aware of is that a persons first reaction to seeing someone go down in a confined space is to go in to help them and then passing out too. They tell you NEVER go in to help because if you do they might be taking two bodies out.
Yes. The next time you finish a 2-liter bottle of soda, do the following:
exhale as completely as you can.
remove the cap from the (empty) bottle.
seal your lips around the bottle top.
gently squeeze the bottle as you inhale its contents.
Its contents include a high residual concentration of CO2 left behind by the soda. If this is a bottle of soda that was opened and finished in a fairly short time span (e.g. at a party), then the concentration will be pretty high, and you’ll immediately feel a strong urge to breathe, as though you had been holding your breath for a minute or two.
You will feel normal, but you will not last three minutes. For occupants of an aircraft at 50,000 feet that loses cabin pressure, their time of useful consciousness is 6-9 seconds; for you in a roomful of N2/helium, it’s probably not much longer. People who take a drag of helium from a party balloon to amuse themselves with a squeaky voice usually do it just once with a partial-inhale, which means they’ve got some residual air that continues to provide at least a bit of oxygen to the blood; they can last maybe 20-30 seconds before they start to feel dizzy. OTOH if you are inhaling pure N2/helium for several breaths in a row, the O2 concentration in your lungs rapidly drops to zero, and oxygen will start to diffuse out of your blood and into your lungs. In either case (one breath or multiple breaths), you will eventually start to feel dizzy without ever having felt the urge to draw fresh breath.
This almost happened at my workplace a few years ago. Two fire safety contractor employees were on site, working on a CO2 fire suppression system when they discharged it, flooding the room with CO2. For reasons unknown, one of the men entered the room, and soon collapsed unconscious. The second man entered the room to retrieve him, very nearly succumbing himself; he became dizzy and had to leave the room to draw fresh breath before returning to drag the first guy the rest of the way out. These were guys who had been specifically trained to install/service CO2 fire suppression systems and were certainly aware of the hazards. I don’t know if the contractor waited for the first guy to be discharged from the hospital before they fired both of them.
I’ve often wondered the same thing. My guess is bureaucratic inertia, along with opposition from opponents of CP. If you are opposed to CP, it doesn’t help your cause to have new methods introduced that are easier and cause less suffering.
I assume this is why people will fall unconscious much more quickly than if they were merely not breathing? And why you shouldn’t attempt to rescue someone who fell unconscious in this nitrogen-filled room?
Yes. Someone may enter a hypoxic environment thinking “I can hold my breath for two minutes, so I should be fine in this nitrogen filled pit for thirty seconds,” not realizing that by breathing while they’re in the pit, they’re not going to last even thirty seconds.
Also, if you take a deep breath and hold it, well great, you can probably last a minute or two; holding your breath (with lungs full of air) in a room filled with nitrogen is no different from holding your breath in a room filled with air. Depending on circumstances, a minute or two may be enough time for you to rescue someone else.
However:
-if you absentmindedly cough or otherwise exhale/inhale while you’re in there, you’ve got just a few seconds to get out, which may be a problem if you happen to be far from the exit.
-when it comes to educating (and setting policy for) a large number of employees who may have widely varying backgrounds about matters of workplace safety, simpler is better. It’s easiest to enforce a simple policy: if you see someone unconscious in a hypoxic environment, call the emergency number to summon the trained professionals, who will arrive quickly with SCBA equipment and extract the victim. If you try to rescue the victim yourself and manage to survive the attempt, you will be fired.
Some patients with COPD (Chronic Obstructive Pulmonary Disease) have chronically elevated levels of CO2 in their blood. These patients DO rely on low oxygen levels to trigger their breathing and often live with borderline low oxygen in their blood at all times.
This can be potentially dangerous if they are placed on higher than needed supplemental oxygen. As their blood oxygen levels increase, their trigger to breath decreases which causes their CO2 levels to rise even further. As CO2 levels rise, they become confused, then sleepy, then comatose.
Much of the exhaled CO[sub]2[/sub] is transported dissolved in the blood plasma as H[sub]2[/sub]CO[sub]3[/sub] - carbonic acid. The need to breathe is triggered by lowering blood pH as detected in the carotid body and aortic body.
This can be a problem for freedivers who suffer from shallow water blackout when ascending from depth or technical divers who forget to change gases from their back gas.
As a freediver descends from the surface to 20 meters, the air in his lungs compresses to one third its initial volume. This initially provides a partial pressure of oxygen of about 0.48 which is higher than the 0.16 which is atmospheric.
If he stays at depth long enough his body consumes oxygen. Suppose the ppO[sub]2[/sub] in the residual air in his lungs drops from 0.48 down to 0.24. As he ascends to a depth of 10 meters the ambient pressure drops and thus the ppO[sub]2[/sub] drops to 0.16 which is still sufficient to maintain consciousness - barely. As he ascends further the ppO[sub]2[/sub] drops to a level that does not support consciousness before he reaches the surface.
For a technical diver, he may use a back gas mixture with a ppO[sub]2[/sub] that would be hypoxic at the surface. Training emphasizes the need to switch to a different gas cylinder with a higher ppO[sub]2[/sub] when in shallow water.
I have actually seen this happen when I was a kid. At a science demo a fellow kid was handed the pipe to a helium tank. He took a deep lungful of helium, started to say something, got the giggles when he heard how stupid he sounded, and couldn’t finish his sentence. He then drew in a second breath and tried talking some more. He got a few words into his sentence and then just trailed off (by this point his lips had turned dark blue) and collapsed on the floor like a sack of potatoes. Can’t have been more than 10 seconds, probably much less.
Needless to say every adult in the vicinity leapt into action but he revived almost as fast, and was very confused why he was on the floor and everyone was flapping. Once they established he was fine, we got a lecture as to what had happened. Lungs emptied of air, filled with inert helium. O2 and CO2 diffuse out of the blood into lungs. Lungs then emptied and refilled with more pure helium - more CO2 diffusing out (so no feel of ‘suffocation’ and no triggering of the normal mechanisms) and, crucially, yet more O2 - so now blood oxygen saturation is plummeting since the body is also burning through it at a normal rate. Brain starved of O2 - lights out.
The normal lungs->blood flow of oxygen reverses if you have a lungful of pure inert gas since even a very low level of blood oxygen is much higher than in the pure helium/nitrogen/whatever.
Something’s backwards here, because a high concentration of CO2 would cause us to feel the need to breathe very strongly, and would more likely lead to hyperventilation than to passing out from not breathing.
The soda-bottle experiment above should convince us of that, if we doubt it.
My son had a leak in one of his co2 lines he uses in his converted freezer that he stores all his beer kegs in. I stuck my head in trying to find the leak and woke up on the floor, my son was scared to death. I thought I would have started gasping for air but all I remember was an intense burning in my lungs.