Should 'Hypercapnia Experience' Be Part Of Training?

ROB DAVIE · 15th May 2005, 01:22

Quote: (Originally Posted by Divechick)

I am pretty sure I managed to give myself a C02 hit from inside a sleeping bag many years ago ...

Quote: (Originally Posted by Caveseeker7)

Does that mean you and your sleeping bag will volunteer for my experience?

Think I just changed my opinion.

Quote: (Originally Posted by Divechick)

Certainly - will be happy to assist by zipping you into a sleeping bag and leaving you there!

{/QUOTE]

Originally posted by Rob Davie
{QUOTE=Rob Davie]Nice try, big boy! Close, but no cigar!!

buggeriamold · 15th May 2005, 02:23

Having had a couple of goes at co2 on deepish air dives on open circuit, it would have taken a lot of convincing that there was a real benifit for me to willingly submit mys self to a "hypercapnia experiance".

Mark

Pawel · 15th May 2005, 02:41

I don't think hypercapnia experience should be mandatory. It could make a false sense of confidence and the symptomps are quite obvious, really. It is just reacting to those symptoms seems to be difficult (at least to me). In my experience I had tunnel vision, difficulty breathing and I was dizzy

. It was plain obvious. But, it was much more difficult to reach out and fush. Then, when this didn't seem to help, I did what Stefan recommends to me all the time: stand up and breathe fresh air - it worked magic

. OK, I didn't quite stand up coz there was no bottom, but at least I made it to the surface and breathing air

It is the drill exercise that I see of more value. I think everyone should exercise "stand up and breathe air" technique (and, of course other bail out options available).
I think hypercapnia experience can be successfully substituted with much more rewarding way of getting dizzy by going to a pub

Just my 2c

Cheers,

Pawel

ROB DAVIE · 15th May 2005, 06:00

Quote: (Originally Posted by Pawel)

I think hypercapnia experience can be successfully substituted with much more rewarding way of getting dizzy by going to a pub

Just my 2c

Cheers,

Pawel

Good idea, Olly!

Rob

JonnyB · 15th May 2005, 07:09

I actually asked my intructor to give my this experience, but not in the way that you guys are describing it. I was talking to him about me wanting to try it, so what we did was that i took out the scrubber, turned on the O2 and the monitors, sat my but on the floor, so i dont hit my head to hard when/if i faint... would not be too nice!
And i started breathing it. Because i did not have any scrubber in i believe the hit i got was way more dramatic that the one you would get initially on a breakthrough, so the signs are not really comparrable, but after just a few minutes, i could get all the describes symptoms we talked about during the course. I got really scared there for a while, i felt panic, remorse, i actually felt suicidal, short breath, tunnel vision etc etc... Ohh yeah and a #¤%() headache... my god.... it got so bad, i aborted before passing out. I aborted though in a way like i was underwater, as i was on surface and wanted O2, i flushed the system with O2 instead of diluent, and i started going SCR, just to try - Do not recomend that as a bailout procedure for hypercapnia, i just wanted to try, so i went SCR for a few minutes then i went OC on 100%O2, what a relief...
Worth it, worth having your head being squashed by an elefants foot for the rest of the day? DEFINATELLY, i really apreciated getting that experience. I know that the signs may vary from time to time, from person to person. But I for one have alot more respect for the scrubber now than before... I know that some people are pushing the sofnolime up to 5-6 hours in cold water, frequently, i change mine after 4-4½ hours regardless, and living in Cyprus you cannot say that our waters are cold... Do i recommend you doing it? No, dont blame me. If you want atleast see to that you do together with someone who can help you.

just my 2cents
/Jonny

***caveseeker7*** · 15th May 2005, 07:41

Quote: (Originally Posted by JonnyB)

Worth it, worth having your head being squashed by an elefants foot for the rest of the day?

I was wondering what that helmet is for ...

Thanks for the radically oposing view and recounting you experience.

cedricverdier · 15th May 2005, 09:00

Quote: (Originally Posted by JonnyB)

I actually asked my intructor to give my this experience/Jonny

I think the hypercapnia skill is definitely a no-no experience during the initial training of a rebreather diver. There is a lot of other skills to learn that are much more valuable and need time to master. The if-in-doubt-bailout (or Open Loop) reaction is clearly something that should become second nature.

Nevertheless, this experience could be interesting for a Mixed Gas CCR Diver.
As CCR divers become more experienced and go deeper, then very often get a false sense of safety (the bulletproof syndrome and the associated denial). Some of them tend to minimize the signs they could experiment

and think that can easily deal with any problem.

During their subsequent CCR training, the hypercapnia experience is a good way to show what could happen in case of scrubber breakthrough. If it's done properly, there is no risk for the student; Instructors like Tom Mount are enthusiastic about the necessity of such skills.

If an experienced CCR diver never got any warning signs of CO2 hit, it becomes a valuable skill, even if the signs are not always the same. I have the feeling that the more tools you have in your toolbox, the more capable you become to understand what happens and how to react.

Feel free to

Cheers

***Decodiver*** · 15th May 2005, 14:32

I am against doing CO2 experience sessions, as much as I am against doing Hypoxia experience sessions also.

I experienced them in the military and question their overall use.

With my students, I prefer to fully explain, discuss and identify the possible symptoms of Hypercapnia and then design them all out by correct preparation and use of the CCR.

I have had CO2 hits, they are not fun.

I firmly believe you can avoid them by proper preparation, on the very small percentage of times that they could happen to a CCR diver I am not sure that one experience would aid identification.

As symptoms change on different days per different persons then this could lead to a false sense of security.

Just my Euro two cent's worth.

Cheers,

Dave Cooper.

***jradomski*** · 15th May 2005, 17:56

Quote: (Originally Posted by TechBlue)

Personally I don't think an induced hypercapnia hit is worth the potential danger. In most cases even when you have a student finning against the wall in a pool with an empty scrubber they are waiting and watching for symptoms and even while they are totally focused many simply fin until they passout, for others who do feel the symptoms many get a false sense of security that they can easily handle a Hypercania hit. As any of you know when you do take a hit at depth you may be aware that all is not well but the paranoia and lack of confidence that accompanies it can take extreme effort to go off the loop and switch to a bailout reg (another good reason for a OC/CC DSV) and this is where your skillsets come through.

I don't agree..

The instructor should be directly supervising the student.. In physical contact with the student.. It is VERY aparrant when a student is starting to get to the later stages of co2.. At this point the instructor should Abort the excercise.. I would also say there are exceptions to this... But you would REALLY have to know the student well...

at ANDI I am REQUIRED to to a hypercapnia excercise, the student can abort it at ANY time.. This includes taking a breath or two and calling it..
ANDI has required this for their Rebreather classes since they started teaching RBS well over a decade ago (and we still have a PERFECT accident/insurance claim free training record - 17 years and counting). If the student doesn't want to go farther than this so be it I am not going to force (neither is any other instructor) the issue... MOST students stop the skill as soon as they feel disconfort in the chest (this is a good place to stop it and I stress that if they reach this point stop it).. alot stop it as soon as they see the elevation in their breathing (this is b4 any discomfort)... If they wait for the disconfort they will probably get a nice headache afterwards...
I HAVE stopped a few that started showing signs that their finning was starting to get sloppy.. This is the early part of the later stages of CO2 (their finning will get VERY sloppy, near blackout) and if the student didn't abort it here(first sign of sloppy finning), The instructor should.. This also indicates they need even more talking to about hypercapnia

I have only let ONE student go past this point.. I know the person extremely well and the person's mental attitude.. I knew what he would be thinking (that he could handle it- no matter what I told him), sure enough he did push it and momentary "pass out".. If I didn't do this to this PARTICULAR person I am 100% sure in a real life situation he would have pushed it.. The second he stopped finning I justed lifted his head, the dsv fell out and he was instaneously conscious...

He described the event to me as, "I felt things were getting bad but I could handle more, then the pool rung bent, my vision went dark then you have me head above the water, which I didn't remember you doing", now this guy flushes the loop at ANY potential sign of tbl.. I am sure he will know what to do... (I have seen him do precautionary flushes more than once already)

I am against Hypoxia excercises and think they are too dangerous. Hypercapnia drills run correctly should be safe.. The proper limits have to be enforced.. The goal is for them to see SOME of the POTENTIAL symptoms not to pass out..

I am for anything that can raise a persons respect for CO2 and their awareness level.. The symptoms can vary but there is still nothing like KNOWING what a potential particular symptom may feel like..

I personally get a very dark narc.. I all of a sudden get this sense of impending doom (before other symptoms may be recognized). The increased breathing may go unnoticed, the chest disconfort doesn't, but my dark narc for me really hits home.. on real dives I have had 3 CO2 issues, on every single one of them I got this Dark narc which I immediately realized (not to say it will happen again), and quickly cleared with a fresh loop flush.. If the symptoms progressed further I don't know what would have happened, but the fact is I recognized the issue and corrected it..

On one I had a partially flooded scrubber - The loop had a leak but passed both pos and negative pressure test prior to the dive.

On one It was a second deep dive (after asecnding from the deepest point about 100m or so ) on a scrubber (the first dive was aborted - so no real time was put on the scrubber - including prebreathe probably 10-20 minutes) but apparantly the sun backed a block of the material into a pretty solid mess and I ended up having to swim very hard against a stiff current at about 60m or so..

The 3rd wasn't a scrubber failure but for certain reasons I wasn't paying attention to my breathing patterns and I was breathing quite shallow.. A quick loop flush and deep breaths solved that..

dive2dive2000 · 16th May 2005, 00:32

Joe,

How many CCR divers have you certified in the last 17 yrs?

Martin

15th May 2005, 01:22	#11 (permalink)
ROB DAVIE Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: HOUSTON, REPUBLIC OF TEJAS Posts: 1,120	Quote: (Originally Posted by Divechick) I am pretty sure I managed to give myself a C02 hit from inside a sleeping bag many years ago ... Quote: (Originally Posted by Caveseeker7) Does that mean you and your sleeping bag will volunteer for my experience? Think I just changed my opinion. Quote: (Originally Posted by Divechick) Certainly - will be happy to assist by zipping you into a sleeping bag and leaving you there! {/QUOTE] Originally posted by Rob Davie {QUOTE=Rob Davie]Nice try, big boy! Close, but no cigar!! __________________ "CC Rebreathers will become a viable part of tech diving WHEN PIGS FLY!!"--GI3
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15th May 2005, 02:23	#12 (permalink)
buggeriamold Custom Title Allowed! Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Feb 2005 Location: australia Posts: 100	Having had a couple of goes at co2 on deepish air dives on open circuit, it would have taken a lot of convincing that there was a real benifit for me to willingly submit mys self to a "hypercapnia experiance". Mark __________________ Well, it is cheap stuff and it comes almost from the local gardening store, but it works fine and it's very solid. We tried to destroy one by hitting it with a hammer... we succeeded but we really had to hit it hard.
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15th May 2005, 02:41	#13 (permalink)
Pawel New Member Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Apr 2005 Location: Sydney, Australia Posts: 68	I don't think hypercapnia experience should be mandatory. It could make a false sense of confidence and the symptomps are quite obvious, really. It is just reacting to those symptoms seems to be difficult (at least to me). In my experience I had tunnel vision, difficulty breathing and I was dizzy. It was plain obvious. But, it was much more difficult to reach out and fush. Then, when this didn't seem to help, I did what Stefan recommends to me all the time: stand up and breathe fresh air - it worked magic . OK, I didn't quite stand up coz there was no bottom, but at least I made it to the surface and breathing air It is the drill exercise that I see of more value. I think everyone should exercise "stand up and breathe air" technique (and, of course other bail out options available). I think hypercapnia experience can be successfully substituted with much more rewarding way of getting dizzy by going to a pub Just my 2c Cheers, Pawel
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15th May 2005, 06:00	#14 (permalink)
ROB DAVIE Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: HOUSTON, REPUBLIC OF TEJAS Posts: 1,120	Quote: (Originally Posted by Pawel) I think hypercapnia experience can be successfully substituted with much more rewarding way of getting dizzy by going to a pub Just my 2c Cheers, Pawel Good idea, Olly! Rob __________________ "CC Rebreathers will become a viable part of tech diving WHEN PIGS FLY!!"--GI3
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15th May 2005, 07:09	#15 (permalink)
JonnyB Johnny The Hatch Current Rebreather/s: MK 15.X Titan Other CCR Other SCR Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Megalodon Sport Kiss Classic Kiss Other CCR Other SCR Home Build Join Date: Jan 2005 Location: Sweden (Stockholm)/Cyprus(Ayia Napa) Posts: 991	I actually asked my intructor to give my this experience, but not in the way that you guys are describing it. I was talking to him about me wanting to try it, so what we did was that i took out the scrubber, turned on the O2 and the monitors, sat my but on the floor, so i dont hit my head to hard when/if i faint... would not be too nice! And i started breathing it. Because i did not have any scrubber in i believe the hit i got was way more dramatic that the one you would get initially on a breakthrough, so the signs are not really comparrable, but after just a few minutes, i could get all the describes symptoms we talked about during the course. I got really scared there for a while, i felt panic, remorse, i actually felt suicidal, short breath, tunnel vision etc etc... Ohh yeah and a #¤%() headache... my god.... it got so bad, i aborted before passing out. I aborted though in a way like i was underwater, as i was on surface and wanted O2, i flushed the system with O2 instead of diluent, and i started going SCR, just to try - Do not recomend that as a bailout procedure for hypercapnia, i just wanted to try, so i went SCR for a few minutes then i went OC on 100%O2, what a relief... Worth it, worth having your head being squashed by an elefants foot for the rest of the day? DEFINATELLY, i really apreciated getting that experience. I know that the signs may vary from time to time, from person to person. But I for one have alot more respect for the scrubber now than before... I know that some people are pushing the sofnolime up to 5-6 hours in cold water, frequently, i change mine after 4-4½ hours regardless, and living in Cyprus you cannot say that our waters are cold... Do i recommend you doing it? No, dont blame me. If you want atleast see to that you do together with someone who can help you. just my 2cents /Jonny
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15th May 2005, 07:41	#16 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,555	Quote: (Originally Posted by JonnyB) Worth it, worth having your head being squashed by an elefants foot for the rest of the day? I was wondering what that helmet is for ... Thanks for the radically oposing view and recounting you experience. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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15th May 2005, 09:00	#17 (permalink)
cedricverdier S21 M.I.B. Current Rebreather/s: Evolution Megalodon Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Worldwide! Posts: 498	Quote: (Originally Posted by JonnyB) I actually asked my intructor to give my this experience/Jonny I think the hypercapnia skill is definitely a no-no experience during the initial training of a rebreather diver. There is a lot of other skills to learn that are much more valuable and need time to master. The if-in-doubt-bailout (or Open Loop) reaction is clearly something that should become second nature. Nevertheless, this experience could be interesting for a Mixed Gas CCR Diver. As CCR divers become more experienced and go deeper, then very often get a false sense of safety (the bulletproof syndrome and the associated denial). Some of them tend to minimize the signs they could experiment and think that can easily deal with any problem. During their subsequent CCR training, the hypercapnia experience is a good way to show what could happen in case of scrubber breakthrough. If it's done properly, there is no risk for the student; Instructors like Tom Mount are enthusiastic about the necessity of such skills. If an experienced CCR diver never got any warning signs of CO2 hit, it becomes a valuable skill, even if the signs are not always the same. I have the feeling that the more tools you have in your toolbox, the more capable you become to understand what happens and how to react. Feel free to Cheers __________________ Cedric Verdier PADI Course Director, ANDI-IANTD-PSAI-TDI-DSAT-DAN-NAUI-CMAS Instructor Trainer Trimix (CCR and OC) and Cave Diving Instructor Trainer www.CedricVerdier.com DIRrebreather member
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15th May 2005, 14:32	#18 (permalink)
*Decodiver* Administrator Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,194	I am against doing CO2 experience sessions, as much as I am against doing Hypoxia experience sessions also. I experienced them in the military and question their overall use. With my students, I prefer to fully explain, discuss and identify the possible symptoms of Hypercapnia and then design them all out by correct preparation and use of the CCR. I have had CO2 hits, they are not fun. I firmly believe you can avoid them by proper preparation, on the very small percentage of times that they could happen to a CCR diver I am not sure that one experience would aid identification. As symptoms change on different days per different persons then this could lead to a false sense of security. Just my Euro two cent's worth. Cheers, Dave Cooper. __________________ CCR/OC Trimix Instructor Trainer CCR Training to Mixed Gas in Switzerland, France, UK & Germany on Megalodon/COPIS-Megalodon/KISS/Sport KISS/Ouroboros/rEvo/Inspiration/Evolution/Sentinel www.zerogravitydiving.com Rebreather World Terms & Conditions
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15th May 2005, 17:56	#19 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,113	Quote: (Originally Posted by TechBlue) Personally I don't think an induced hypercapnia hit is worth the potential danger. In most cases even when you have a student finning against the wall in a pool with an empty scrubber they are waiting and watching for symptoms and even while they are totally focused many simply fin until they passout, for others who do feel the symptoms many get a false sense of security that they can easily handle a Hypercania hit. As any of you know when you do take a hit at depth you may be aware that all is not well but the paranoia and lack of confidence that accompanies it can take extreme effort to go off the loop and switch to a bailout reg (another good reason for a OC/CC DSV) and this is where your skillsets come through. I don't agree.. The instructor should be directly supervising the student.. In physical contact with the student.. It is VERY aparrant when a student is starting to get to the later stages of co2.. At this point the instructor should Abort the excercise.. I would also say there are exceptions to this... But you would REALLY have to know the student well... at ANDI I am REQUIRED to to a hypercapnia excercise, the student can abort it at ANY time.. This includes taking a breath or two and calling it.. ANDI has required this for their Rebreather classes since they started teaching RBS well over a decade ago (and we still have a PERFECT accident/insurance claim free training record - 17 years and counting). If the student doesn't want to go farther than this so be it I am not going to force (neither is any other instructor) the issue... MOST students stop the skill as soon as they feel disconfort in the chest (this is a good place to stop it and I stress that if they reach this point stop it).. alot stop it as soon as they see the elevation in their breathing (this is b4 any discomfort)... If they wait for the disconfort they will probably get a nice headache afterwards... I HAVE stopped a few that started showing signs that their finning was starting to get sloppy.. This is the early part of the later stages of CO2 (their finning will get VERY sloppy, near blackout) and if the student didn't abort it here(first sign of sloppy finning), The instructor should.. This also indicates they need even more talking to about hypercapnia I have only let ONE student go past this point.. I know the person extremely well and the person's mental attitude.. I knew what he would be thinking (that he could handle it- no matter what I told him), sure enough he did push it and momentary "pass out".. If I didn't do this to this PARTICULAR person I am 100% sure in a real life situation he would have pushed it.. The second he stopped finning I justed lifted his head, the dsv fell out and he was instaneously conscious... He described the event to me as, "I felt things were getting bad but I could handle more, then the pool rung bent, my vision went dark then you have me head above the water, which I didn't remember you doing", now this guy flushes the loop at ANY potential sign of tbl.. I am sure he will know what to do... (I have seen him do precautionary flushes more than once already) I am against Hypoxia excercises and think they are too dangerous. Hypercapnia drills run correctly should be safe.. The proper limits have to be enforced.. The goal is for them to see SOME of the POTENTIAL symptoms not to pass out.. I am for anything that can raise a persons respect for CO2 and their awareness level.. The symptoms can vary but there is still nothing like KNOWING what a potential particular symptom may feel like.. I personally get a very dark narc.. I all of a sudden get this sense of impending doom (before other symptoms may be recognized). The increased breathing may go unnoticed, the chest disconfort doesn't, but my dark narc for me really hits home.. on real dives I have had 3 CO2 issues, on every single one of them I got this Dark narc which I immediately realized (not to say it will happen again), and quickly cleared with a fresh loop flush.. If the symptoms progressed further I don't know what would have happened, but the fact is I recognized the issue and corrected it.. On one I had a partially flooded scrubber - The loop had a leak but passed both pos and negative pressure test prior to the dive. On one It was a second deep dive (after asecnding from the deepest point about 100m or so ) on a scrubber (the first dive was aborted - so no real time was put on the scrubber - including prebreathe probably 10-20 minutes) but apparantly the sun backed a block of the material into a pretty solid mess and I ended up having to swim very hard against a stiff current at about 60m or so.. The 3rd wasn't a scrubber failure but for certain reasons I wasn't paying attention to my breathing patterns and I was breathing quite shallow.. A quick loop flush and deep breaths solved that.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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16th May 2005, 00:32	#20 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 796	Joe, How many CCR divers have you certified in the last 17 yrs? Martin
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