From: story@sgi.com (David (Duis) Story)
Subject: Re: missing deco stop ... re-entering
Organization: Silicon Graphics, Inc.
Date: Mon, 14 Dec 92 18:37:10 GMT

In article <gf9EBrq00UzxI3tFMa@andrew.cmu.edu> ps3p+@andrew.cmu.edu (Peter A. Simon) writes:
>[ original attribution lost, I believe this was from Dan Kell? ]
>>	* if DCS has already occurs, the only feasible way to get bubbles
>>	  back into solution is to go to a chamber (in the water it would
>>	  require far too much time at far too great of depths.
>
>Wrong!  To get bubbles back into solution requires increasing the
>ambient pressure.  The source of the pressure is immaterial.  It would
>require the same pressure and time in a chamber as it would in the water.

Actually, I believe the original poster was referring to the fact that
for serious (lifethreatening) DCI, compression is often to 165fsw.
This is simply not possible in some areas (bottom is too shallow) and
the decompression from the required bottom time for symptom resolution
is going to be a real problem, both for the victim and the
attendant(s).

Still want to do in-water recompression?

Also, on- and off-gassing and the effects of O2 toxicity have
experimentally proven to be very different in wet and dry conditions.

>>2) breathe pure oxygen
>
>IF AVAILABLE.

It should be if you are planning decompression.  (Emphasis on
"planning": Remember the 6 P's.)

>>For all you advanced divers trained in decompression diving:
>> 
>>In the event that you do one, plan it so that you don't have the problem 
>>discussed above: "Plan your dive, dive your plan."  Make sure that you
>>have tanks left at the appropriate depths so that you don't have to miss
>>your stops. Make sure that you do have oxygen on board.  Make sure you 
>>have the numbers and locations of the nearest diving physician and chamber.
>>If there is no nearby chamber, maybe the dive shouldn't be done in the
>>first place.
>
>Lots of people who cruise world side in their own boats have scuba gear
>aboard.  They get themselves in some pretty remote places, places where
>no one has ever dived before.  Places where there are no chambers and no
>doctors trained in hyperbaric medicine.  They dive and take their
>chances.  Your advice above leaves them (and others who don't want to
>limit themselves to the well-trodden path--like myself) hanging out to dry.

I fail to see how your point is justified.  The original poster is
simply pointing out the appropriate safety precautions taken by
careful divers when doing decompression diving.  There is nothing
about being in a remote location that changes the logistics of
decompression diving.

Why aren't these risk takers insuring themselves appropriately?  By
having the proper safety equipment and redundancy, DCI risk is greatly
reduced.  Obviously it can't be completely eliminated, therefore the
nearest physician and chamber should be known.  There is always a
"nearest" chamber even if it's quite far away.  Diving accident
insurance can greatly extend your range -- pressurized jet aircraft
_are_ available to those with the $$$ and ability to summon them,
pretty much regardless of location.

>Instead of dispensing received wisdom and blabbing fiats, why
>don't you enter into the spirit of free inquiry and do a little
>research.  MY interest in this discussion is to learn, not to be
>subjected to anecdotal evidence about what another "informed source"
>says I must or must not do.

If I might make a suggestion, toning this down would probably help the
"spirit of free inquiry."  That advice also applies to statements like
"WRONG!" -- which don't exactly encourage folks to contribute to the
discussion.  

Other than that, glad to have you posting.  

Cheers,

David Story                        NAUI AI Z9588, PADI DM 43922, EMT
story@bent.wpd.sgi.com		   Oxygen is a drug in California.
Newsgroups: rec.scuba