The undetectable killer

PCDiver · 9th July 2008, 05:55

The incident rate among rebreather divers is high, extremely high. Something is defenitely wrong. Is it the equipment that we use, our skills, the deco algorithms we use?

I've been thinking about this quite a lot because it really worries me.
Is it possible that there is a killer out there that is undetectable after an accident? I know of one that I have experienced several times and that other people have reported it as well even recently ... CO2 retention.

CO2 retention causes feelings of unease, severe breathing problems, panic, hyperventilating, ... Underwater these can easily result in a drowning. It also happens very quickly. In less than 30 seconds you can go from "nice dive, yeah some current" to "I'm gonna die".

Will your buddy notice this? Perhaps, but in a low vis situation and because it all happens very quickly, chances are that he doesn't and that he finds you unconscious or sees you bolting for the surface.

Will an investigation find this afterwards? Not likely. In most cases the machine was working perfectly, but your boddy wasn't.

Experienced divers, and I mean, not divers with lots of rebreather hours, but the ones that have experienced a CO2 retention problem, will recognise the symptoms early and slow down or even bailout. The other ones ... If they or their buddy take the correct action they survive otherwise they become another mystery casualty.

I have experienced severe CO2 retention a couple of times. The first time as a rather novice rebreather diver a couple of years ago. I had to bailout at 50 meters with a over half an hour of deco. I was even overbreathing my Poseidon regulator because my RMV was through the roof. I survived because I managed to stay calm and because of assistance of my buddy. Later on we tried to figure out wat happened but we found nothing wrong with the rebreather, the gasses, the sorb, ...

Later I had other CO2 retention issues, or the beginning thereof, a couple of times, always in a big current pushing a monster of a camera.

I always assumed that it was a personal problem, that I'm a CO retainer, but I'm not so sure anymore. Recently, reports on CO2 retaining incidents have been comming in on rebreatherworld from several people, DrMike, Gill, Dave S, ...

Perhaps we all have underestimated CO2 retention. Perhaps it is the undetectable killer that causes havoc among our rebreather diving population.

Just an idea.

chunter · 9th July 2008, 06:28

The times where I have seen people nearly die were all entirely diver error. This is not to say that there aren't equipment failures, but like in car accidents, most problems happen because people do not pay attention. Rebreathers are able to kill in a number of ways, and when people lose the respect for them that they deserve, they die. Most pilots wouldn't jump into a Cessna without having done the pre-flight checks, but people seem to do this regularly with rebreathers. It is suicidal in my opinion.

My feeling is that 95% of rebreather deaths are totally avoidable. With proper gear preparation, dive planning, pre-dive checks, good diving habits, maintainance, etc., the likelyhood of death is greatly reduced.

There may be some deaths out there that are the result of "undetectable killers", and the best way to avoid them is to stop diving. I think these instances are a very small part of the problem, and won't keep me out of the water.

Aloha,
Charlie

PCDiver · 9th July 2008, 06:32

Charlie,

thanks for your reply.
I would like to keep this thread on the topic of "CO2 retention". I want to find out what other peoples experience is with CO2 retention and how they see it as a potential cause of accidents.

Peter

Drmike · 9th July 2008, 07:07

Quote: (Originally Posted by PCDiver)

The incident rate among rebreather divers is high, extremely high. Something is defenitely wrong. Is it the equipment that we use, our skills, the deco algorithms we use?

I've been thinking about this quite a lot because it really worries me.
Is it possible that there is a killer out there that is undetectable after an accident? I know of one that I have experienced several times and that other people have reported it as well even recently ... CO2 retention.

CO2 retention causes feelings of unease, severe breathing problems, panic, hyperventilating, ... Underwater these can easily result in a drowning. It also happens very quickly. In less than 30 seconds you can go from "nice dive, yeah some current" to "I'm gonna die".

Will your buddy notice this? Perhaps, but in a low vis situation and because it all happens very quickly, chances are that he doesn't and that he finds you unconscious or sees you bolting for the surface.

Will an investigation find this afterwards? Not likely. In most cases the machine was working perfectly, but your boddy wasn't.

Experienced divers, and I mean, not divers with lots of rebreather hours, but the ones that have experienced a CO2 retention problem, will recognise the symptoms early and slow down or even bailout. The other ones ... If they or their buddy take the correct action they survive otherwise they become another mystery casualty.

I have experienced severe CO2 retention a couple of times. The first time as a rather novice rebreather diver a couple of years ago. I had to bailout at 50 meters with a over half an hour of deco. I was even overbreathing my Poseidon regulator because my RMV was through the roof. I survived because I managed to stay calm and because of assistance of my buddy. Later on we tried to figure out wat happened but we found nothing wrong with the rebreather, the gasses, the sorb, ...

Later I had other CO2 retention issues, or the beginning thereof, a couple of times, always in a big current pushing a monster of a camera.

I always assumed that it was a personal problem, that I'm a CO retainer, but I'm not so sure anymore. Recently, reports on CO2 retaining incidents have been comming in on rebreatherworld from several people, DrMike, Gill, Dave S, ...

Perhaps we all have underestimated CO2 retention. Perhaps it is the undetectable killer that causes havoc among our rebreather diving population.

Just an idea.

I would say that CO2 retention has been the most common of my near miss issues.

If multitasking or exerting its so easy to not notice increasing retained co2 (brought on for a number of reasons) until your at the feeling of panic stage. at that point its strength of mind that will make the difference "if i panic I die, If I panic I die" repeat as often as necessary.

One reason I dont agree with the RAN theory about getting used to CO2 hits makes one push their luck is because Ive noticed that knowing that I have survived co2 hits (your never sure at the time if its retained or inspired) before by calming down, calming my breathing, flushing/bailing and most importantly by NOT panicing, goes a very very long way to reducing my stress and enabling me to not panic and begin to take control of the situation.

IMO its the panic that is our imediate theat with retained co2 - at least it has been for me. You stop your exersion (or solve the ventilation issues) then fight back thoughts of panic. Knowing that you have sucessfully done that before I found helps a lot to help you do it again as the confidence that gives you aids fighting the feelings panic

...well thats what ive found anypoo

**Steve** · 9th July 2008, 07:14

Quote: (Originally Posted by Drmike)

I would say that CO2 retention has been the most common of my near miss issues.

If multitasking or exerting its so easy to not notice increasing retained co2 (brought on for a number of reasons) until your at the feeling of panic stage. at that point its strength of mind that will make the difference "if i panic I die, If I panic I die" repeat as often as necessary.

One reason I dont agree with Steves theory about getting used to CO2 hits makes one push their luck is because Ive noticed that knowing that I have survived co2 hits (your never sure at the time if its retained or inspired) before by calming down, calming my breathing, flushing/bailing and most importantly by NOT panicking, goes a very very long way to reducing my stress and enabling me to not panic and begin to take control of the situation.
IMO its the panic that is our imediate theat with retained co2 - at least it has been for me. You stop your exersion then fight back thoughts of panic. Knowing that you have sucessfully done that before I found helps a lot to help you do it again as the confidence that gives you aids fighting the feelings panic

...well thats what ive found anypoo

Not my theory. IIRC it was John Pennefather

Drmike · 9th July 2008, 07:44

something to bare in mind:

Theres a new gadget you can buy:

This one gadget will give you the following benefits:

Improved WOB
Improved Drag
Shorter decompression
Improved ventilation and gas exchange

all in all one of the most effective safety devices you can buy and its really cheap:

Here it is

**Steve** · 9th July 2008, 07:54

Why does it not surprise me that you wear women's shoes?

Drmike · 9th July 2008, 08:04

Quote: (Originally Posted by Steve)

Why does it not surprise me that you wear women's shoes?

Im also wearing womens underwear - but only because thats the way johnK likes me

PCDiver · 9th July 2008, 08:11

Fitness and CO2 retention. Do we know how many of the divers that had an accident were not in good physical condition (age, overweight, ...)

Jim · 9th July 2008, 08:20

Quote: (Originally Posted by Drmike)

something to bare in mind:

Theres a new gadget you can buy:

This one gadget will give you the following benefits:

Improved WOB
Improved Drag
Shorter decompression
Improved ventilation and gas exchange

all in all one of the most effective safety devices you can buy and its really cheap:

Here it is

Dr M,

Nail on Head ..... say no more ..... too many fat, unfit, underqualified and over ambitious, over confident and complaecent divers are adding to the 'RIP' list ...... It is a physical sport, kitting up in a dry suit, sweating your proverbials off, standing up wearing ???KGS of kit, in a nasty weather, then jumping into bloody cold water for a 2hr+ deco dive ...... and then we ask why did it happen?? What other sport puts your body and mind through this stress? Obviously, this doesn't cover all accidents but I bet my right nut one of the above will cover the majority.

You need to be fit, I'd say very fit to seriously dive a CCR for all the reasons Mike listed and more. My buddy has a very physically demanding job, still he has lost nearly 1.5 stone running and training in prep for two weeks of 100m+ diving later this year. Why? Beacuase he is realistic about the consequences of such dives if he is not in shape.

Sorry for the rant - appreciate some may feel harsh or off topic (mostly the unfit ones hiding behind the TV

) but CO2 retention can also be avoided in a large part by being able to breathe comfortably and in a controlled manner while exerting yourself in stressful situations.

Give yourself every chance of coming back safely - stay fit, stay vigilant and prep your kit like your life depends on it. I've had a CO2 hit on open circuit in a rip in Burma, in my limited 550+ hours on CCR I fortunately have'nt had the problem - I put this down to all the types of preperation.

I want to die shagging on my 100th birthday.

Be safe.

9th July 2008, 05:55	#1 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 970	The undetectable killer The incident rate among rebreather divers is high, extremely high. Something is defenitely wrong. Is it the equipment that we use, our skills, the deco algorithms we use? I've been thinking about this quite a lot because it really worries me. Is it possible that there is a killer out there that is undetectable after an accident? I know of one that I have experienced several times and that other people have reported it as well even recently ... CO2 retention. CO2 retention causes feelings of unease, severe breathing problems, panic, hyperventilating, ... Underwater these can easily result in a drowning. It also happens very quickly. In less than 30 seconds you can go from "nice dive, yeah some current" to "I'm gonna die". Will your buddy notice this? Perhaps, but in a low vis situation and because it all happens very quickly, chances are that he doesn't and that he finds you unconscious or sees you bolting for the surface. Will an investigation find this afterwards? Not likely. In most cases the machine was working perfectly, but your boddy wasn't. Experienced divers, and I mean, not divers with lots of rebreather hours, but the ones that have experienced a CO2 retention problem, will recognise the symptoms early and slow down or even bailout. The other ones ... If they or their buddy take the correct action they survive otherwise they become another mystery casualty. I have experienced severe CO2 retention a couple of times. The first time as a rather novice rebreather diver a couple of years ago. I had to bailout at 50 meters with a over half an hour of deco. I was even overbreathing my Poseidon regulator because my RMV was through the roof. I survived because I managed to stay calm and because of assistance of my buddy. Later on we tried to figure out wat happened but we found nothing wrong with the rebreather, the gasses, the sorb, ... Later I had other CO2 retention issues, or the beginning thereof, a couple of times, always in a big current pushing a monster of a camera. I always assumed that it was a personal problem, that I'm a CO retainer, but I'm not so sure anymore. Recently, reports on CO2 retaining incidents have been comming in on rebreatherworld from several people, DrMike, Gill, Dave S, ... Perhaps we all have underestimated CO2 retention. Perhaps it is the undetectable killer that causes havoc among our rebreather diving population. Just an idea. __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews and Wreck dive videos >>>>> Now also on iTunes and Zune
(Online)

9th July 2008, 06:28	#2 (permalink)
chunter I like diving Current Rebreather/s: Sport Kiss MK 15.X Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Classic Kiss Join Date: Jul 2006 Location: Honolulu Posts: 478	Re: The undetectable killer The times where I have seen people nearly die were all entirely diver error. This is not to say that there aren't equipment failures, but like in car accidents, most problems happen because people do not pay attention. Rebreathers are able to kill in a number of ways, and when people lose the respect for them that they deserve, they die. Most pilots wouldn't jump into a Cessna without having done the pre-flight checks, but people seem to do this regularly with rebreathers. It is suicidal in my opinion. My feeling is that 95% of rebreather deaths are totally avoidable. With proper gear preparation, dive planning, pre-dive checks, good diving habits, maintainance, etc., the likelyhood of death is greatly reduced. There may be some deaths out there that are the result of "undetectable killers", and the best way to avoid them is to stop diving. I think these instances are a very small part of the problem, and won't keep me out of the water. Aloha, Charlie __________________ "Foolish consistency is the hobgoblin of little minds." - Emerson "Hobgoblin is a cool word." - Charlie
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9th July 2008, 06:32	#3 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 970	Re: The undetectable killer Charlie, thanks for your reply. I would like to keep this thread on the topic of "CO2 retention". I want to find out what other peoples experience is with CO2 retention and how they see it as a potential cause of accidents. Peter __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews and Wreck dive videos >>>>> Now also on iTunes and Zune Last edited by PCDiver : 9th July 2008 at 06:36.
(Online)

9th July 2008, 07:07	#4 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,325	Re: The undetectable killer Quote: (Originally Posted by PCDiver) The incident rate among rebreather divers is high, extremely high. Something is defenitely wrong. Is it the equipment that we use, our skills, the deco algorithms we use? I've been thinking about this quite a lot because it really worries me. Is it possible that there is a killer out there that is undetectable after an accident? I know of one that I have experienced several times and that other people have reported it as well even recently ... CO2 retention. CO2 retention causes feelings of unease, severe breathing problems, panic, hyperventilating, ... Underwater these can easily result in a drowning. It also happens very quickly. In less than 30 seconds you can go from "nice dive, yeah some current" to "I'm gonna die". Will your buddy notice this? Perhaps, but in a low vis situation and because it all happens very quickly, chances are that he doesn't and that he finds you unconscious or sees you bolting for the surface. Will an investigation find this afterwards? Not likely. In most cases the machine was working perfectly, but your boddy wasn't. Experienced divers, and I mean, not divers with lots of rebreather hours, but the ones that have experienced a CO2 retention problem, will recognise the symptoms early and slow down or even bailout. The other ones ... If they or their buddy take the correct action they survive otherwise they become another mystery casualty. I have experienced severe CO2 retention a couple of times. The first time as a rather novice rebreather diver a couple of years ago. I had to bailout at 50 meters with a over half an hour of deco. I was even overbreathing my Poseidon regulator because my RMV was through the roof. I survived because I managed to stay calm and because of assistance of my buddy. Later on we tried to figure out wat happened but we found nothing wrong with the rebreather, the gasses, the sorb, ... Later I had other CO2 retention issues, or the beginning thereof, a couple of times, always in a big current pushing a monster of a camera. I always assumed that it was a personal problem, that I'm a CO retainer, but I'm not so sure anymore. Recently, reports on CO2 retaining incidents have been comming in on rebreatherworld from several people, DrMike, Gill, Dave S, ... Perhaps we all have underestimated CO2 retention. Perhaps it is the undetectable killer that causes havoc among our rebreather diving population. Just an idea. I would say that CO2 retention has been the most common of my near miss issues. If multitasking or exerting its so easy to not notice increasing retained co2 (brought on for a number of reasons) until your at the feeling of panic stage. at that point its strength of mind that will make the difference "if i panic I die, If I panic I die" repeat as often as necessary. One reason I dont agree with the RAN theory about getting used to CO2 hits makes one push their luck is because Ive noticed that knowing that I have survived co2 hits (your never sure at the time if its retained or inspired) before by calming down, calming my breathing, flushing/bailing and most importantly by NOT panicing, goes a very very long way to reducing my stress and enabling me to not panic and begin to take control of the situation. IMO its the panic that is our imediate theat with retained co2 - at least it has been for me. You stop your exersion (or solve the ventilation issues) then fight back thoughts of panic. Knowing that you have sucessfully done that before I found helps a lot to help you do it again as the confidence that gives you aids fighting the feelings panic ...well thats what ive found anypoo __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment Last edited by Drmike : 9th July 2008 at 07:35.
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9th July 2008, 07:14	#5 (permalink)
Steve Ladies bring a plate Current Rebreather/s: Megalodon Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Classic Kiss MK 15.X Home Build Join Date: Feb 2005 Location: Perth - Australia Posts: 1,117	Re: The undetectable killer Quote: (Originally Posted by Drmike) I would say that CO2 retention has been the most common of my near miss issues. If multitasking or exerting its so easy to not notice increasing retained co2 (brought on for a number of reasons) until your at the feeling of panic stage. at that point its strength of mind that will make the difference "if i panic I die, If I panic I die" repeat as often as necessary. One reason I dont agree with Steves theory about getting used to CO2 hits makes one push their luck is because Ive noticed that knowing that I have survived co2 hits (your never sure at the time if its retained or inspired) before by calming down, calming my breathing, flushing/bailing and most importantly by NOT panicking, goes a very very long way to reducing my stress and enabling me to not panic and begin to take control of the situation. IMO its the panic that is our imediate theat with retained co2 - at least it has been for me. You stop your exersion then fight back thoughts of panic. Knowing that you have sucessfully done that before I found helps a lot to help you do it again as the confidence that gives you aids fighting the feelings panic ...well thats what ive found anypoo Not my theory. IIRC it was John Pennefather __________________ WARNING: I contain occasional coarse language, extreme sexual references, nudity, and adult themes, which may offend some people - Usually churchy types. Last edited by Steve : 9th July 2008 at 07:26. Reason: edited out Edmonds. Def not him.
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9th July 2008, 07:54	#7 (permalink)
Steve Ladies bring a plate Current Rebreather/s: Megalodon Home Build Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Classic Kiss MK 15.X Home Build Join Date: Feb 2005 Location: Perth - Australia Posts: 1,117	Re: The undetectable killer Why does it not surprise me that you wear women's shoes? __________________ WARNING: I contain occasional coarse language, extreme sexual references, nudity, and adult themes, which may offend some people - Usually churchy types.
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9th July 2008, 08:04	#8 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,325	Re: The undetectable killer Quote: (Originally Posted by Steve) Why does it not surprise me that you wear women's shoes? Im also wearing womens underwear - but only because thats the way johnK likes me __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
(Offline)

9th July 2008, 08:11	#9 (permalink)
PCDiver Submerge Productions Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: Belgium Posts: 970	Re: The undetectable killer Fitness and CO2 retention. Do we know how many of the divers that had an accident were not in good physical condition (age, overweight, ...) __________________ >>>>> www.submergeproductions.com dedicated to promoting technical diving >>>>> Check out our dive show video interviews and Wreck dive videos >>>>> Now also on iTunes and Zune
(Online)

9th July 2008, 08:20	#10 (permalink)
Jim Lovable Cockhead ! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Jun 2005 Location: Purley, UK Posts: 146	Re: The undetectable killer Quote: (Originally Posted by Drmike) something to bare in mind: Theres a new gadget you can buy: This one gadget will give you the following benefits: Improved WOB Improved Drag Shorter decompression Improved ventilation and gas exchange all in all one of the most effective safety devices you can buy and its really cheap: Here it is Dr M, Nail on Head ..... say no more ..... too many fat, unfit, underqualified and over ambitious, over confident and complaecent divers are adding to the 'RIP' list ...... It is a physical sport, kitting up in a dry suit, sweating your proverbials off, standing up wearing ???KGS of kit, in a nasty weather, then jumping into bloody cold water for a 2hr+ deco dive ...... and then we ask why did it happen?? What other sport puts your body and mind through this stress? Obviously, this doesn't cover all accidents but I bet my right nut one of the above will cover the majority. You need to be fit, I'd say very fit to seriously dive a CCR for all the reasons Mike listed and more. My buddy has a very physically demanding job, still he has lost nearly 1.5 stone running and training in prep for two weeks of 100m+ diving later this year. Why? Beacuase he is realistic about the consequences of such dives if he is not in shape. Sorry for the rant - appreciate some may feel harsh or off topic (mostly the unfit ones hiding behind the TV ) but CO2 retention can also be avoided in a large part by being able to breathe comfortably and in a controlled manner while exerting yourself in stressful situations. Give yourself every chance of coming back safely - stay fit, stay vigilant and prep your kit like your life depends on it. I've had a CO2 hit on open circuit in a rip in Burma, in my limited 550+ hours on CCR I fortunately have'nt had the problem - I put this down to all the types of preperation. I want to die shagging on my 100th birthday. Be safe. __________________ Jim Spence
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