Dry Hypoxia Training for Rebreather Divers

Have you ever done an intentional dry hypoxia exposure?

  • Yes, monitored by a professional in training.

    Votes: 7 8.0%

  • Yes, at home with a friend.

    Votes: 8 9.1%

  • Yes, but as a part of an aviation training course.

    Votes: 2 2.3%

  • No, but believe that it might be useful for rebreather divers.

    Votes: 51 58.0%

  • No way, you kidding me?

    Votes: 23 26.1%
  • Total voters
    88
Meh stupid auto correct on the ipad, should caught that one. Regardless, you got my point.

Yes, i read the previous posting, however being Canadian does not entitle me to use American funding, infrastructure, etc without paying for it. Perhaps I am wrong on that part? If so please let me know, so I can make a trip down to the US so i can use the medical facilities there free of charge :). Furthermore, if these tests are basically free of charge, why are you not taking your students(friends) there to have this experiment done instead of on your living room couch? It would greatly enhance their safety/comfort with having this done, not to mention if you present this correctly and document it, you could potentially present this to the rebreather manufactures/agencies and lobby for a change to the standards, which would allow you to be supported by the insurance underwriter you carry for instruction(you do have insurance for being an instructor right?).

If you do get this set up for free let me know I will gladly make the trip to do the course as it would be interesting to have done, besides its always great to meet new people and share stories. Regardless that is off topic and should be separated out into another thread.

You also stated earlier if i remember correctly, that these experiences are already being undertaking in the comfort your living room with students again why are you not using the free/cheap service that is available to do this in a controlled environment.

Enough internet diving for now time to go do the real thing! I suggest we all do the same thing then have a beer or for some out here(BC) a chai latte with extra foam :(.


Steve

Sent from my iPad using Tapatalk HD
 
I participated in a similar study.
Breathing in the loop without removing CO2 from the decline of oxygen. and second breathing pure nitrogen in an open circuit.

Breathing quickly without removing CO2 increases ventilation and is strongly indicated. There is a linear increase in the volume of ventilation with the deepening of inspiration.
Completely different breathing pure nitrogen, the initial breaths do not have an increased volume is nice and relaxed with a delay increases the depth of breath but it is nice.

In contrast to the pilot, a diver is also under the influence of ppN2, reduce perception already exists.

That is why I am taking an extreme opponent of such experiments in low security. My Osen performed in a hospital with good security and monitoring ppO2, ppCO2, tidal volume, and frequency and vacuum measurement inspiration.

rc greet
 
Dave, this is very old school and IMHO is also quite dangerous. I don't believe that there will be any defensible position that an instructor will be able to take if and when something goes south on him during a course. Kind of like the old school method of teaching where the instructor sneaks up on student from behind and turns off the student's valve waiting to watch how the student responds. Completely unnecessary and indefensible from a liability position and teaches the student absolutely nothing!
Just my $.02, but I feel very strongly about it! (By the way, this is also the position of TDI)

Regards,
Randy
 
I find it quite surprising that this has stirred up such a lot of passion.

We'll happily:-

Subject ourselves to an air chamber dry dive to 40m +
Free dive below 30m at which point our lungs get irreversibly crushed
Do controlled buoyant lifts from various depths
More importantly be the 'casualty' for a fellow trainee for such drills

but

for another controlled experience which is done regularly around the world for other participants some of us are up in arms?

Could be just me, but I find this interesting.
There again over the years:-

I dived voodoo gas Nitrox,
Used one of those killer Low Pressure Inflator gizmos on my ABLJ
Used a jacket style BCD which will kill everyone who uses them as they don't float you on your back,
Used a wing which will drown me instantly as it floats me face down
Dived the devil gas trimix,
Wear the suicide Full Face Mask
and now dive a death trap rebreather with FFM.

I must be mad and the luckiest person in the world as I think I've survived these alternate ideas over the decades even though the ABLJ is still and well in the dive locker ready for the return to basics.

Sarcasm? Moi? Never.
 
Randy Thornton said:
Dave, this is very old school and IMHO is also quite dangerous. I don't believe that there will be any defensible position that an instructor will be able to take if and when something goes south on him during a course. Kind of like the old school method of teaching where the instructor sneaks up on student from behind and turns off the student's valve waiting to watch how the student responds. Completely unnecessary and indefensible from a liability position and teaches the student absolutely nothing!
Just my $.02, but I feel very strongly about it! (By the way, this is also the position of TDI)

Regards,
Randy
Click to expand...




Randy,

Why don't you read the entire thread? I am advocating taking professionally conducted aerospace physiology training as it has huge training similarities to rebreather diving. This isn't "old school". It's leading edge synergy with a different industry (that frankly spends millions for every $10k we spend developing training systems). "Couch dives" are done... Lets move towards a new paradigm.

Who cares what TDI says? PADI used to throw out instructors who mentioned nitrox... ;-)

(And when I teach aviation subjects... I teach as an FAA licensee... Not as a diving instructor... My experiences using ROBS systems for "couch dives" has been as an aerospace professional, not as a dive instructor, and I was trained to give this training by one if the leading providers of such training. I've put hundreds of pilots thru it. It's not a hypothetical situation to me)


I abdolutely understand the objections: they do not come from an industry that has addressed this before. It's absolutely routine for pilots.

Dave


.
 
Last edited:
Dave Sutton said:
This isn't "old school". It's leading edge synergy with a different industry (that frankly spends millions for every $10k we spend developing training systems). "Couch dives" are done... Lets move towards a new paradigm.
Click to expand...

You know method of killing unwanted dogs, in which air is evacuated from the container in which the dog is closed?

The dive has no effect easy breathing, due to decreased air density.
This is one of the subtle effects of aviation.

CCR must control ppO2, on separate power systems.

greet rc
 
Randy Thornton said:
Dave, this is very old school and IMHO is also quite dangerous. I don't believe that there will be any defensible position that an instructor will be able to take if and when something goes south on him during a course. Kind of like the old school method of teaching where the instructor sneaks up on student from behind and turns off the student's valve waiting to watch how the student responds. Completely unnecessary and indefensible from a liability position and teaches the student absolutely nothing!
Just my $.02, but I feel very strongly about it! (By the way, this is also the position of TDI)

Regards,
Randy
Click to expand...

I'll just chime in and say that the wording "quite dangerous" is exaggerating the dangers by a lot. From a medical perspective this would be harmless for the overwhelming majority and a slight risk for a small subset of people. On the other hand the latter group would likely have a far greater cardiac risk if they went on a rebreather dive. I only had a cursory look at some of the studies but it seems well tested and safe for the aviation industry even if some of the studies were a bit questionable in design. How well it would translate into diving is another matter but I don't see any reason to dismiss it because it would be dangerous.
 
Johan Isaksson said:
I'll just chime in and say that the wording "quite dangerous" is exaggerating the dangers by a lot. From a medical perspective this would be harmless for the overwhelming majority and a slight risk for a small subset of people. On the other hand the latter group would likely have a far greater cardiac risk if they went on a rebreather dive. I only had a cursory look at some of the studies but it seems well tested and safe for the aviation industry even if some of the studies were a bit questionable in design. How well it would translate into diving is another matter but I don't see any reason to dismiss it because it would be dangerous.
Click to expand...

Which is more dangerous - the test, or thinking you know this signs after a single-couch-exposure?
 
I am reminded of the movie "Flatliners"
Just because Mr Sutton feels qualified to monitor a diver's descent into near unconsciousness and back does not mean this should be attempted by us mere mortal average Joe CCR instructors.
I assume that the testing performed by FAA is conducted under the supervision of a fully trained and qualified medical person and not just someone who read about this on the internet.
 
I voted no way, but once I actually read what Dave was proposing, I completely agree.

In a controlled professional environment, this if nothing else, would make people check their PPO2 more often.

It would be great to see at least the videos showing the effects of hypoxia be written into MOD 1 CCR courses (I know they have the chapters/sections in the training material, but the videos would enforce this). I remember watching the sky news team video about hypercapnia, and I certainly believe it was much more effective training because my instructor showed me that.

It would be even better as an option to go participate in a controlled and professional environment like Dave is suggesting. The Aviation industry is already doing it and have hard data supporting the evidence, so why not use this to our advantage?!

Great thread, makes me want to seek out if this is viable for me to try cheaply in Oz, thanks!

Pete
 
Megangel1 said:
Personally, I'm quite interested in how long I'd have on the surface breathing a 10/50 dil before a). I'm incapable of being able to give an emergency signal to the boat or b). actually being able to mentally realise that I'm really in the sticky stuff and that I need to signal the boat and NOT swim hard back to the ladder in the first place or c). just go night night Zzzzzzzz!

I know, I know we don't want to be in that position, but if I HAD to breath the 10/50 OC, how long could I expect to be able to float around waiting to be picked up. ( eg bailout tins removed ready to climb ladder / get into RHIB in rough seas and I break the loop on the ladder or something)
Click to expand...

The problem with giving emergency signals is not whether or not you could give one, but whether or not the responders respond immediately instead of fluffing about for half an hour while they work out whether its' real or not. With something like hypoxia you don't have the time to wait while they work it out so self rescue is largely the order of the day.
 
I'm wondering, with this diver who is not watching their handset or the HUD for a long period of time - unaware that the ADV is firing and oblivious to the fact that the solenoid is not going. SPG not checked.

This diver, who has consumed all their oxygen in this way, but is familiar with the hypoxic signs - what are they going to do about it?

If they did not have the presence of mind to make the checks then I have no confidence that they will perform the correct drill once mentally impaired. Sudden ascent would be a poor but perhaps likely choice?

Matt.
 
How quickly falls ppO2 in closed circuit?

Opt for low-capacity circuit. 5l breathing bag, canister with hoses and residual lung capacity diver 4,5 l Comes about 10l.
(Soda lime has a porosity of 66%).
In how much time ppO2 drops from 0.2 to 0.1 at?
The metabolism of oxygen to the diver sitting 0.5 l / min decrease of 0.1 ppO2 achieve after 2 minutes.
For moderate-intensity 1.5 l / min, the legacy of 40s achieve.
The constant depth.

Which plane as quickly enters the ceiling of 5500 m above sea level. in the 40s?
Gaping explosive plane is faster or louder.

greet rc
 
matthewoutram said:
Which is more dangerous - the test, or thinking you know this signs after a single-couch-exposure?
Click to expand...

This is making a large assumption about the psychology of the diver involved. I don't think anyone has stated that performing such a drill would equip the diver to be able to identify the signs and therefore for-go such things as HUDs and proper monitoring.

I totally agree with the assertions such as proper monitoring etc. I also agree that some divers might think that based upon such a drill, that they'll know the signs of hypoxia. However, I know more than one diver who are confident that they can recognise hypoxia, hyperoxia or hypercapnia anyway! So where's the difference? Maybe, just maybe such a drill will show them that they don't have a clue, especially when shown the video of themselves.

Or put another way I don't think this is an exercise in training one to recognise hypoxia, but an exercise in showing that one cannot readily recognise it or deal with it!

Can't see the danger in such a experience session if conducted properly.
 
erikradstrom said:
Dave, if you do this the way you wrote in the beginning. The mouthpiece so that it will fall out if you pass out it will fall out of your mouth.

How big is the risk? You pass out without the mouthpiece and then what? You just wake up when you took a few breaths or do you need assistance?
Click to expand...

If your head flops back the mouthpiece could stay in, if it flops forward the mouthpiece could wedge between your mouth and chest, either way you could wind up unconscious with the mouthpeice still in. May not have a secure seal from the lips but still not good.
 
Megangel1 said:
This is making a large assumption about the psychology of the diver involved.
...
Can't see the danger in such a experience session if conducted properly.
Click to expand...

I'm just making the opposite assumption to you - unless you can point me to the study data?

The test seems non-dangerous according to the posts made by Dave et al so I don't think that a concern. My point is only related to how the single-exposure data is subsequently applied by the diver experiencing it.

Matt.
 
Osiris said:
The problem with giving emergency signals is not whether or not you could give one, but whether or not the responders respond immediately instead of fluffing about for half an hour while they work out whether its' real or not. With something like hypoxia you don't have the time to wait while they work it out so self rescue is largely the order of the day.
Click to expand...

But is self-rescue a realistic possibility in the case of hypoxia? As seen in the vid, if one can not self rescue just by putting the mask back on when repeatedly TOLD to do so while seated in a controlled, dry environment, what chance does a diver have of self-rescue?

In the case of falling off a ladder and compromising the integrity of the loop, one is going to sink and needs to breath something. If my DIL is 10/50, do I have the time near/on the surface to breath it while I'm rescued, or do I take my chances in rough waves with my FFM off and trying to breath air, remember I might only just be slightly +ve buoyant?

Which leads me even further off-topic with a question:- where can I get a Surface Air Valve for a Nova from and is there any point given the p-ports are low down on the mask?
 
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