Children die playing with scuba gear left in pool - Jensen Beach, Florida

[Dan]

Thanks for that DDM, but is there any truth to the story that it is very difficult to revive someone who has breathed pure helium? As although thats what I was told 'back in the day', the only incident I have first hand knlowledge of suggests it is not (hard to revive them).

After 10 minutes?

 

[Kay Dee]

After 10 minutes?

Are you asking 'after 10 mins breathing 100% helium'? If so, how could one do that? From reading DDM's answer, wouldn't one have passed out and 'died' long before that (10 mins had elapsed) and not be breathing at all? Hence my question re the difficulty supposedly reviving a 100% helium breathing victim.

 

[beester]

Are you asking 'after 10 mins breathing 100% helium'? If so, how could one do that? From reading DDM's answer, wouldn't one have passed out and 'died' long before that (10 mins had elapsed) and not be breathing at all? Hence my question re the difficulty supposedly reviving a 100% helium breathing victim.

Trust me breathing 100% He on the surface will pass you out within 1 min, even 30 seconds. But this is getting totally off topic on such a tragic post.

 

[ginti]

This is difficult to write, I have kids around that age. Breathing pure helium causes the oxygen in the bloodstream to rapidly diffuse into the lungs, which leads to immediate hypoxemia and rapid loss of consciousness.

Out of curiosity, is that because of the different gas density of He and O2?

 

[Wookie]

Inert gas asphyxiation is a form of asphyxiationwhich results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen,[1] rather than atmospheric air(which is largely composed of nitrogen and oxygen). Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium, nitrogenand methane. The term "physiologically inert" is used to indicate a gas which has no toxic or anesthetic properties and does not act upon the heart or hemoglobin. Instead, the gas acts as a simple diluent to reduce oxygen concentration in inspired gas and blood to dangerously low levels, thereby eventually depriving all cells in the body of oxygen.[2]

According to the U.S. Chemical Safety and Hazard Investigation Board, in humans, "breathing an oxygen deficient atmosphere can have serious and immediate effects, including unconsciousness after only one or two breaths. The exposed person has no warning and cannot sense that the oxygen level is too low." In the US, at least 80 people died due to accidental nitrogen asphyxiation between 1992 and 2002.[3]Hazards with inert gases and the risks of asphyxiation are well established.[4]

 

[Dan]

Are you asking 'after 10 mins breathing 100% helium'? If so, how could one do that? From reading DDM's answer, wouldn't one have passed out and 'died' long before that (10 mins had elapsed) and not be breathing at all? Hence my question re the difficulty supposedly reviving a 100% helium breathing victim.

From what I read, you’ll pass out after a breath or two of pure helium. So, “after 10 minutes?” means the likelihood of someone reviving a victim after 10 minutes without oxygen is practically nil, as far as I know.

 

[mderrick]

Another way to explain it...
Most divers know that the first aid for someone exhibiting signs and symptoms of DCI is to administer 100% oxygen or as close to it as possible with a tight fitting non rebreather mask. We teach dive accident O2 providers the purpose of the 100% oxygen is not to better perfuse the victim with oxygen, it is to create as much as possible of a pressure differential in the lungs for the inert gas (usually nitrogen) in order to more rapidly diffuse the nitrogen.

We know from altitude studies of aircraft pilots that a PPO2 of 0.10 ata (the equivalent of breathing a 10% oxygen mixture at the surface) will take 10 to 15 minutes before the average adult experiences LOC. (Although maximum useful consciousness will be lost sooner.) However, breathing 100% inert gas (helium, nitrogen, argon, etc) the LOC will occur much quicker; perhaps with just a few breaths. That's because the higher gradient caused by breathing a gas containing zero oxygen will cause tissue oxygen to more rapidly diffuse from the body. In this case it's not just that oxygen consumed by the body is not being replaced, it's that oxygen is literally being rapidly pulled out of the body by the differential created from breathing 100% helium.

Some readers might not understand why there is no sense of being unable to breathe or anxiety such as might be experienced when holding your breath. That's because for normal healthy individuals the need to breathe is triggered by the amount of CO2 not O2 in the blood. If breathing 100% inert gas, most people will not experience an urgency to breathe.

 

[Duke Dive Medicine]

Thanks for that DDM, but is there any truth to the story that it is very difficult to revive someone who has breathed pure, i.e 100% helium? As although thats what I was told 'back in the day', the only incident I have first hand knlowledge of suggests it is not (hard to revive them).

First, I want to remain mindful of the underlying tragedy. This is going to sound like I'm reducing it to a clinical explanation and that's not my intent. My heart breaks for this family.

It depends on how quickly the individual is removed from the environment. The one person I met who it happened to was a U.S. Navy diver who had stuck his head up inside a saturation bell that was full of helium due to an undiscovered gas leak. He took one breath and basically self-rescued by passing out and falling back through the bell hatch into fresh air. The only thing he got was a nasty bump on his head. The probability of survival goes down very quickly the longer the individual is exposed though - much more quickly than someone who has gone into respiratory arrest from (for example) a drug overdose and is simply deprived of oxygen. Pure helium (or any other pure gas that isn't oxygen, as @Wookie pointed out) will act like an oxygen vacuum because of the large diffusion gradient between the bloodstream and the lungs. This results in extremely rapid hypoxemia, which would lead quickly to irreversible tissue damage. So, minute for minute, it would be much more difficult to resuscitate someone who had breathed pure helium, and that's on dry land. In the water, an unconscious individual would drown quickly.

<edit> I was typing this as @mderrick was typing his well-considered post above - same idea, different wording.

 

[DanBMW]

I don't know if this is relevant, but as a comparison, I was on a high altitude skydive, and supposedly breathing pure oxygen for about 15 minutes, from 10,000 feet ASL. An 02 hose was just in my mouth. At around 15,000 feet, I suffered hypoxia and passed out with no previous symptoms. I might have had a bad O2 line. To this day I do not remember anything just prior to passing out. The other people in the airplane jumped at around 17,000 feet and one other person rode the airplane down with me.

05/01/2021 added...... One more note about hypoxia. In the service, I experienced controlled hypoxia and learned some of the things to look at for, like reds loosing color, tunnel vision, tingling fingers and graying out. NONE were felt of experienced before I passed out.

 

[Esprise Me]

First, I want to remain mindful of the underlying tragedy. This is going to sound like I'm reducing it to a clinical explanation and that's not my intent. My heart breaks for this family.

It depends on how quickly the individual is removed from the environment. The one person I met who it happened to was a U.S. Navy diver who had stuck his head up inside a saturation bell that was full of helium due to an undiscovered gas leak. He took one breath and basically self-rescued by passing out and falling back through the bell hatch into fresh air. The only thing he got was a nasty bump on his head. The probability of survival goes down very quickly the longer the individual is exposed though - much more quickly than someone who has gone into respiratory arrest from (for example) a drug overdose and is simply deprived of oxygen. Pure helium (or any other pure gas that isn't oxygen, as @Wookie pointed out) will act like an oxygen vacuum because of the large diffusion gradient between the bloodstream and the lungs. This results in extremely rapid hypoxemia, which would lead quickly to irreversible tissue damage. So, minute for minute, it would be much more difficult to resuscitate someone who had breathed pure helium, and that's on dry land. In the water, an unconscious individual would drown quickly.

<edit> I was typing this as @mderrick was typing his well-considered post above - same idea, different wording.

This is really surprising and chilling. I remember kids breathing off party balloons to make their voices squeaky. (Do those maybe not contain pure helium?) I was always too scared to do it.