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Hi Everyone,

Richard Pyle wote this in response to J Shepard;
>> mentioned 138 mins, but the bends that have occurred close to me have
>> been 4 to 6 hours at 2.6 bar O2 in a chamber (later compressions being
>> deeper and longer and usually not leading to complete relief of symptoms
>> :-( ).
>
>I would guess that's more a result of delay to recompression.  There's
>very little information on how patients respond to DCI in a chamber when
>treated within 5-10 minutes of the onset of symptoms (doesn't happen very
>often).  There seems to be growing evidence that time to recompression is
>of utmost importance in determining whether noticable permanent damage
>occurs.

Richard I don't agree that treatment within 5-10 minutes "doesn't happen
very often".  In the commercial world, with on site chambers, this is
*exactly* what happens.  The recovery rates are so good that many commercial
chamber operators consider that any bend can be completly cleared up.  When
I did my commercial chamber operator's course that was very much the feeling
of the instructors.   The general mood was that you use a fairly liberal
table, and any hits are treated at once.  Surface oxygen decompression works
on that principle.  With the table we were using, you miss your 6 and 3
metre (20 and 10 foot) stops, get out of the water, jump in the pot and get
blown down to 12m (40fsw) on O2.  No sweat!  If symptoms appear during the
surface interval, or if you have a delay beyond 7 minutes (from last stop
to chamber bottom) you just switch to a short treatment table.

What I'm saying is that if you have a chamber on site you can fix any deco
problem, that is why they are required for commercial operations.  It is
very comforting diving with a chamber over your head, particularly as you
swim past your last two stops ;)

I think that O2-IWR is about as close as sport divers can get to this sort
of support.

BTW comms is not the only method of comunicating diver to surface and visa
versa.  Line signals can work just as well (often better!).  A complete
range of things you might want to say are easy to work out and simple to
use.  If you use pulls and bells then you have double the range.  (pulls
are a strong slow tension on the line, evenly spaced.  Bells are short tugs
that come in pairs, like the Ding, Ding.....Ding, Ding of a ship's bell)

Cheers Jason (Upside down)

PS. Line signals must be resent by the reciever so that the sender is sure
they have got the message.  If the sender doesn't get a response, then they
resend the message.

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