HELIOX where to find information?

J. V. · 4th April 2006, 17:28

Quote:

Personaly Id opt for heleox bailout all the way.

It's an option, but it's make often many gases and gas tanks to carry and long deco obligation. For 20 min 90 m hx 10 PpO2 1.3, OC bailout with hx 16, hx 40 and O2 make something like 150 min rt with VPM-B and 180 min with VPM-B.
I prefer the hypotectic risk of ICD.

Cause I don't belive ICD is a risk (in that case), but I'm sure than carrying tanks and tanks make all my dive less pleasant.

Mark Chase · 4th April 2006, 18:02

Quote: (Originally Posted by Mikel-Deko)

Hi Mark

Do you have any reason to opt for Heliox all the way on bailout?

Mikel-Deko

There is empirical data and test data that demonstrates the problems of introducing a spike of Nitrogen during a gas switch. At an extreme the condition is obvious with inner ear bends and symptoms of vertigo.

The more subtle damage may not be so apparent an this may be why people are saying its too shallow or too short an exposure to have an effect.

If i am diving Heleox I see no reason to introduce a third gas into the equation especially under what is going to be an emergency situation. Increased breathing rates adrenalin flowing and stressed may make a difference ( i don't know this for sure but It seems logical)

I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix. I would probably push the deep and intermediate deco a bit and use the drop in PP02 during pure 02 rebreather to monitor how far to push the 6m stop.

As for diluent I normally stick to one.

ATB

Mark Chase

Drmike · 4th April 2006, 18:45

Quote: (Originally Posted by Mark Chase)

I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix.

Really? I find that surprising

J. V. · 4th April 2006, 20:38

Quote:

If i am diving Heleox I see no reason to introduce a third gas into the equation especially under what is going to be an emergency situation. Increased breathing rates adrenalin flowing and stressed may make a difference ( i don't know this for sure but It seems logical)

You're right. In emergency situation gas consumtion often go to high level. That's why I use tmx in place of hx for OC bailout. By adding a little amount of N2, OC deco obligation can be less important than in hx CCR . OC bailout with hx makes deco longer. If you multiplicate gas consumtion by a "stress" safety factor you need many more gas with hx OC than with tmx-nx OC.

Quote:

I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix.

As Drmike, I'm surprised. Have you an example ?
If we found a way to make same OC deco with Hx than with Tmx without carry more tanks, I'll use too Hx bailout.

DrJM · 5th April 2006, 06:39

Guys to make it short:

ICD is an issue !!!

NEVER but NEVER switch back from Heliox to trimix on OC or CCR

If you're diving heliox, you stay on heliox

Off shore industry and the military guys are anal with that

Examples of ICD:
- Exley
- Gomez
- Shirley
- Redoutey
- plus some unknown names

Some ICD will leave sequelles like Don Shirley daily vertigo ...

Now it's a free world, you're big boys and can do whatever you want but don't come crying after ...

Food for thought

Jerome

Mdemon · 5th April 2006, 07:08

That's good enough for me!

I don't fancy puking through my reg for an hour or so of deco...

On the question of ICD the other way round - Trimix to Heliox...

I emailed one of the doctors whose name seems to be on all this sort of research and he kindly gave me a response to a simple question I put to him. The response as follows...

Quote:

"I have been discussing a technique for diving extreme depths with my rebreather diving colleagues and wondered if switching from a nitrogen-rich trimix to a heliox, at depth, would have any adverse bubble-forming effects?

Do you think this technique has any additional risk to it please?"

Quote:

Dear John.

I do not recall wether it has been tested in practice so the answer is purely hypothetical. If the shift is done before any gas formation (bubbles) is likely to have occurred during a staged decompression I doubt the shift to heliox from trimix would have an isobaric bubble forming potential – in this case a possible deep tissue isobaric counter diffusion situation. However, it would probably have a negative consequence for your decompression profile.

Yours Sincerely,
XXXXXXXX, MD, Ph.d.

(I haven't asked if he minds me posting his thoughts so I haven't named him out of courtesy. Just to say that he also works with DAN and is one of the big names in this field. I hope to get a more detailed response shortly.)

So, hypothetically, it doesn't seem there is an obvious risk in switching from trimix to heliox. Just don't do it the other way round...

4th April 2006, 17:28	#61 (permalink)
J. V. Custom Title Allowed! Current Rebreather/s: rEvo Other Rebreather/s: Not Bought Yet rEvo Join Date: Mar 2006 Location: Lot & Savoie Posts: 239	Re: HELIOX where to find information? Quote: Personaly Id opt for heleox bailout all the way. It's an option, but it's make often many gases and gas tanks to carry and long deco obligation. For 20 min 90 m hx 10 PpO2 1.3, OC bailout with hx 16, hx 40 and O2 make something like 150 min rt with VPM-B and 180 min with VPM-B. I prefer the hypotectic risk of ICD. Cause I don't belive ICD is a risk (in that case), but I'm sure than carrying tanks and tanks make all my dive less pleasant. __________________ -------------------- Jacques NPSFQQA-EDS IT # 007 (remué non agité)
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4th April 2006, 18:02	#62 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,700	Re: HELIOX where to find information? Quote: (Originally Posted by Mikel-Deko) Hi Mark Do you have any reason to opt for Heliox all the way on bailout? Mikel-Deko There is empirical data and test data that demonstrates the problems of introducing a spike of Nitrogen during a gas switch. At an extreme the condition is obvious with inner ear bends and symptoms of vertigo. The more subtle damage may not be so apparent an this may be why people are saying its too shallow or too short an exposure to have an effect. If i am diving Heleox I see no reason to introduce a third gas into the equation especially under what is going to be an emergency situation. Increased breathing rates adrenalin flowing and stressed may make a difference ( i don't know this for sure but It seems logical) I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix. I would probably push the deep and intermediate deco a bit and use the drop in PP02 during pure 02 rebreather to monitor how far to push the 6m stop. As for diluent I normally stick to one. ATB Mark Chase __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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4th April 2006, 18:45	#63 (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: 3,323	Re: HELIOX where to find information? Quote: (Originally Posted by Mark Chase) I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix. Really? I find that surprising __________________ 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
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4th April 2006, 20:38	#64 (permalink)
J. V. Custom Title Allowed! Current Rebreather/s: rEvo Other Rebreather/s: Not Bought Yet rEvo Join Date: Mar 2006 Location: Lot & Savoie Posts: 239	Re: HELIOX where to find information? Quote: If i am diving Heleox I see no reason to introduce a third gas into the equation especially under what is going to be an emergency situation. Increased breathing rates adrenalin flowing and stressed may make a difference ( i don't know this for sure but It seems logical) You're right. In emergency situation gas consumtion often go to high level. That's why I use tmx in place of hx for OC bailout. By adding a little amount of N2, OC deco obligation can be less important than in hx CCR . OC bailout with hx makes deco longer. If you multiplicate gas consumtion by a "stress" safety factor you need many more gas with hx OC than with tmx-nx OC. Quote: I wouldn't see me needing any more bottles of bailout when flying He02 than I would flying trimix. As Drmike, I'm surprised. Have you an example ? If we found a way to make same OC deco with Hx than with Tmx without carry more tanks, I'll use too Hx bailout. __________________ -------------------- Jacques NPSFQQA-EDS IT # 007 (remué non agité)
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5th April 2006, 06:39	#65 (permalink)
DrJM Deep Cave Explorer Current Rebreather/s: Ouroboros Other Rebreather/s: MK 15.X Join Date: May 2005 Location: France Posts: 344	Re: HELIOX where to find information? Guys to make it short: ICD is an issue !!! NEVER but NEVER switch back from Heliox to trimix on OC or CCR If you're diving heliox, you stay on heliox Off shore industry and the military guys are anal with that Examples of ICD: - Exley - Gomez - Shirley - Redoutey - plus some unknown names Some ICD will leave sequelles like Don Shirley daily vertigo ... Now it's a free world, you're big boys and can do whatever you want but don't come crying after ... Food for thought Jerome __________________ www.snoopyloop.com Deep Cave Exploration
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5th April 2006, 07:08	#66 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,927	Re: HELIOX where to find information? That's good enough for me! I don't fancy puking through my reg for an hour or so of deco... On the question of ICD the other way round - Trimix to Heliox... I emailed one of the doctors whose name seems to be on all this sort of research and he kindly gave me a response to a simple question I put to him. The response as follows... Quote: "I have been discussing a technique for diving extreme depths with my rebreather diving colleagues and wondered if switching from a nitrogen-rich trimix to a heliox, at depth, would have any adverse bubble-forming effects? Do you think this technique has any additional risk to it please?" Quote: Dear John. I do not recall wether it has been tested in practice so the answer is purely hypothetical. If the shift is done before any gas formation (bubbles) is likely to have occurred during a staged decompression I doubt the shift to heliox from trimix would have an isobaric bubble forming potential – in this case a possible deep tissue isobaric counter diffusion situation. However, it would probably have a negative consequence for your decompression profile. Yours Sincerely, XXXXXXXX, MD, Ph.d. (I haven't asked if he minds me posting his thoughts so I haven't named him out of courtesy. Just to say that he also works with DAN and is one of the big names in this field. I hope to get a more detailed response shortly.) So, hypothetically, it doesn't seem there is an obvious risk in switching from trimix to heliox. Just don't do it the other way round... __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?" Last edited by Mdemon : 5th April 2006 at 07:16.
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