Alternative to Chamber?

[DevonDiver]

Apparently technical divers do IWR all the time. This is from comments from that workshop. They don't even hesitate according to their statements, and the events are never reported nor are medics called. So this is not widely known nor are there reliable statistics gathered, like for military or recreational diver incidents. But the Tech divers are convinced and do IWR all the time when DCS is suspected. I'd assume they would not be enthusiastic if it didn't work for them.

That's a complete fallacy.

I, personally have never, or know of any other tech diver, having completed IWR.

Tech divers may re-descend to complete missed decompression.... but that is very different to conducting IWR after DCIsymptoms have presented.

 

[Thalassamania]

I have to whole-heartedly agree with DD.

 

[DCBC]

Graywhale:

I suppose your questions lend themselves to a more important one. Should you do the dive in the first-place? Commercially, you require the kit and the team before it can be undertaken. Sport Divers should take some notice of the lessons learned by their commercial cousins.

To answer your questions however:

1. What would you have done if it was not available?... But my question is what to do precisely when there isn't a chamber available well past 3 hours?

Get out of the way of the medical staff; otherwise, administer O2, treat for shock, maintain airway, give CRP as necessary, closely monitor and transport!

2. Do you think your buddy would have survived without the quick chamber access?

That's hard to say; quite possibly not. We had excellent medical staff and equipment available. If he survived, there would be a high chance of paralysis. Because there were neurological symptoms, it's really hard to predict his outcome. He was however in great hands and proper management was given. He no longer dives commercially.

3. How long did it take for unconsciousness to set in?

Less than 15 minutes after completion of an in-water decompression schedule (helium tends to bubble faster than nitrogen).

4. I understand the issue about cold water, but your buddy was already equipped for cold water as you stated anyway, no?

Yes and no; he was protected for the dive duration, but had a long dive profile in cold water. In this case the diver was using a hot water dry suit to counteract the extreme loss of body heat caused by cold water immersion while breathing Helium. He had completed a scheduled in-water decompression model and was good to go. The DCS resulted in shock which required further warmth in the management process.

This of course brings-up another point. You can follow all the rules and still get DCS! The DCS in this case was attributed to extensive previous deep diving exposure. This highlights another question...

Why do "recreational trimix divers" not expect more long term bone damage that their air diving counterparts? Somehow the non-professional diver has it in his mind that diving helium is somehow safe (which really amazes me). While you may be decompressing efficiently if all things go perfectly, one problem ascent is all it takes to make your skeleton decay ahead of time! Welcome to the world of the commercial diver...

 

[tgsmith]

Why do "recreational trimix divers" not expect more long term bone damage that their air diving counterparts? Somehow the non-professional diver has it in his mind that diving helium is somehow safe (which really amazes me). While you may be decompressing efficiently if all things go perfectly, one problem ascent is all it takes to make your skeleton decay ahead of time! Welcome to the world of the commercial diver...

Haven't done trimix yet, but I'm guessing you're referring to bone necrosis? From what I understood, it's only a problem with repetitive saturation diving. Not really what we do.....

 

[DCBC]

Haven't done trimix yet, but I'm guessing you're referring to bone necrosis? From what I understood, it's only a problem with repetitive saturation diving. Not really what we do.....

Helium offers a number of problems which includes HPNS (over 150 meters), bone necrosis, avascular necrosis, dysbaric osteonecrosis and the possibility of Helium poisoning.

I think that the UK Sport Diving Medical Committee states it best "The incidence of dysbaric osteonecrosis increases with depths of dives, their duration and the number of exposures. Amateur sport SCUBA divers were considered to be at low risk because their dives were usually short and shallow. As amateur divers go deeper, for longer and use gas mixtures containing helium it is probable that more cases of dysbaric osteonecrosis will come to light.

Failure to learn from past lessons may cause amateur divers to suffer an epidemic of bone necrosis, similar to those in caisson workers in the last century and in professional divers earlier in this century, before safer work practices were introduced to those occupations."

Decompression is NOT an exact science, no matter how much we wish that this was the case...

 

[graywhale]

DCBC,
Thanks again for sharing. However, your situation now seems so extreme, that I certainly would not ever be found in a similar situation and neither would most recreational divers. The bends due to Helium bubbles is entirely different than the bends due to Nitrogen bubbles. In addition, the dive profile of your buddy is also entirely different than anything that either I or most other recreational divers would even dream of doing. Helium toxicity and Helium caused bends affect the body differently, so your experience can not be translated and applied to what I have been reading.

For instance, the onset time of symptoms due to Helium bubbles is much faster and probably more severe than those due to Nitrogen bubbles - from what I read, so then IWR becomes much less of an option. And I agree with you that anyone diving on Helium, should have a team and chamber at the ready anyway.

As to the statement by DevonDiver that it's a fallacy that tech diver do IWR frquenetly, all I can say is I am quoting one here who went to the workshop in Sydney:

JERRY CHIA: I’ll say that this sort of situation happens quite regularly – maybe not to
the extent of this particular victim – and it’s never reported. And also the profile of the
diver does not fit a technical diver. But, yes, I think straight back in the water, definitely.
No doubt about it. In the group of divers that I dive with, we don’t have this sort of
problem occurring regularly, but there’s no reason not. The facilities are there. There is
reasonable expertise to do it. And it’s never reported.

Also from the Workshop:
ALF BRUBAKK: I think probably the most used recompression procedure in the world
is recompression on air in-water. This is used by a lot of people who dive all around
the world with procedures that give them an enormously high risk of decompression sickness. In the little studies I’ve been participating in, the divers don’t know much
about how to do IWR and do it in many different ways. I would suggest that it is high
time we start to study this seriously to see if it is an option, because it appears to me
the U.S. Navy procedure presented is impractical for many of these divers. The data
seems to indicate that if the point is to get rid of the bubbles, you get rid of them much,
much quicker with IWR and can even go back to the surface with a very few bubbles
and repeat the IWR. There are many tricks that can be used probably. I think one of the
problems that we have is that we call it treatment. I would suggest we call IWR
advanced first aid and get around the treatment thing. Then we can go on and do all
the normally accepted treatments afterwards. We should be calling IWR "advanced first
aid." I can remember the discussions of about 20 years ago whether lay people should
be allowed to do CPR: "Only doctors could do it, because CPR could injure." Now
we’re doing CPR all over the place. I suggest that we really seriously to look at IWR
and start programs to actually study how to do it effectively.

 

[DCBC]

DCBC,
Thanks again for sharing. However, your situation now seems so extreme, that I certainly would not ever be found in a similar situation and neither would most recreational divers. The bends due to Helium bubbles is entirely different than the bends due to Nitrogen bubbles. In addition, the dive profile of your buddy is also entirely different than anything that either I or most other recreational divers would even dream of doing. Helium toxicity and Helium caused bends affect the body differently, so your experience can not be translated and applied to what I have been reading.

The onset time of symptoms due to Helium bubbles is much faster and probably more severe than those due to Nitrogen bubbles - from what I read, so then IWR becomes much less of an option. And I agree with you that anyone diving on Helium, should have a team and chamber at the ready anyway.

There's no major difference in the treatment of DCS regardless of the gas (Nitrogen, Oxygen, or Helium) that causes the problem. In-fact, the Israeli Hyperbaric Unit recommends the use of Helium in the treatment of Air induced DCS, because of the benefits it has in removing N2 from fatty tissues (the diffusion coefficients are greater in Helium). The flux of Helium into fat is only half that of N2. So arguably it's easier to treat Helium induced DCS than DCS induced by air, but that's another discussion.

Other than the different absorption / diffusion rates and the scheduled treatment profile, management of a patient is similar. As far as emergency medicine at the scene is concerned (as far as the average person is concerned), there's no difference whatsoever.

The example I used was extreme in that it was a severe case of Type II DCS. This is not however as bad as any Type III DCS, regardless of the mixture. Air divers have died of Type II DCS all too often. Although in this example Helium was involved; air can kill or cripple you just as quick.

There are of course some proponents of IWR; especially research done in Australia. Keeping in-mind the mean water temperature of the world's oceans, I cannot help but discard IWR because of cold-water and resulting hypothermia (especially when the patient is in shock). Good discussion.

 

[graywhale]

DCBC,
I stand corrected, you are right, there is no real difference between the gases. And I hear you on the water conditions. You are professional and don't go without having a contingency plan. I am advocating the same for recreational divers. We've gotten to the point where someone reported a group dive with one participant wearing street pants and a yellow rain coat.

In reality, DCS can kill or permanently harm an individual diving even shallow. In areas where medics and chambers are not too far away, perhaps the divers can rely on that fact. But when that is not the case, divers and DMs should have a contingency plan, even if they are not tech divers and in my untrained and inexperienced opinion, it seems logical to include IWR in a contingency plan, even if it is just a tank of oxygen at the harbor in an area of 30 feet. In the workshops they disclosed that they have lowered a chair to sit on off a pier. So it doesn't have to be complicated if it is planned out in advance if you're very far from any chamber and something real bad happens.

Hoping that nothing too bad happens far from facilities is not a contingency plan in my book, that's why I'm all for IWR in the proper situation. In any case, if the victim is not too bad off on symptoms yet, no harm will likely come of IWR and further treatment can happen later or concurrent with arranging for transport.

I agree, good discussion and I mean on disrespect to anyone, just provoking thoughts and an exchange of info, which I think has happened.

 

[Sloth]

That's a complete fallacy.

I, personally have never, or know of any other tech diver, having completed IWR.

Tech divers may re-descend to complete missed decompression.... but that is very different to conducting IWR after DCIsymptoms have presented.

I would have agreed with this until my Tech 1 instructor told me about their IWR protocol when doing dive excursions in the middle of no where. They practice it and have done it I think he said twice for slight symptoms.

Probably outside of Europe and the US its more common then we think.

 

[Sloth]

Why do "recreational trimix divers" not expect more long term bone damage that their air diving counterparts? Somehow the non-professional diver has it in his mind that diving helium is somehow safe (which really amazes me). While you may be decompressing efficiently if all things go perfectly, one problem ascent is all it takes to make your skeleton decay ahead of time! Welcome to the world of the commercial diver...

I thought the issue was only with saturation divers that spend hours and hours in a helium enriched environment during decompression?

Is that not the case?