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Date: Thu, 07 Jun 2001 13:21:34 +0200
From: mat.voss@t-*.de* (Matthias Voss)
Organization: Harry Haller Memorial Fund
To: Kevin Sumlar <ksumlar@ci*.co*>
CC: techdiver@aquanaut.com
Subject: Re: bouncing - the risks (was RE: Diving after BENDS)
Kevin,
definitely you can/ will get bent.
That is how the commercial divers who clean the nets at the salmon farms
found their way into the DCS statistics. 

I limit rescue training for a maximum of 3 ascents from 12-14 m,
followed by a long stay at depth and a very slow ascent.
Matthias

Kevin Sumlar schrieb:
> 
> Very informative post.  One question about this,
> 
> Could you also get bent like this doing non-deco
> training dives?
> 
> For instance, say I am at the quarry practicing with
> a new lift bag in 50' of water.  If I stay in no-deco
> time limits but am going from 50' to the surface multiple
> times in a short time period would this expose some
> sort of risk of CNS DCS?
> 
> -K
> 
> ----- Original Message -----
> From: Simon L Hartley <shartley@sc*.ed*.au*>
> To: <techdiver@aquanaut.com>
> Cc: <trey@ne*.co*>
> Sent: Tuesday, June 05, 2001 7:38 PM
> Subject: FWD: bouncing - the risks (was RE: Diving after BENDS)
> 
> > >Return-Path: <owner-techdiver@aquanaut.com>
> > >Errors-To: owner-techdiver@aquanaut.com
> > >From: trey@ne*.co* (Trey)
> > >To: "Wkpp@Ya*. Com" <wkpp@ya*.co*>
> > >Subject: bouncing - the risks
> > >Date: Tue, 22 May 2001 07:30:58 -0400
> > >X-MSMail-Priority: Normal
> > >X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6600
> > >Importance: Normal
> > >
> > >
> > > Guys read this for once.
> > >
> > > WHY WE DO NOT BOUNCE DIVE AFTER DIVING IN THE WKPP
> > >
> > >It is ok to offgas from the tissues into the blood stream in bubble form in
> > >the later steps of decompression as it is a more efficient, faster way of
> > >getting rid of the remaining gas ( by reduced pressure ) than by elevated
> > >oxygen alone ( which starts taking exponentially more time with greater
> > >risk) . However, this depends on having a good lung filter and no shunts.
> > >All of you have been PFO tested if you are diving with us.
> > >
> > >The correct way to ascend from the last stop is one foot per minute for the
> > >bigger dives.
> > >
> > >The greatest potential for offgassing in bubble form is when the pressure
is
> > >totally removed back to one ATA out of the water. Now you get a real shower
> > >of bubbles , relative to what was happening in the water. A good , clean
> > >deco with the foot per minute ascent reduces this dramatically .
> > >
> > >In MOST people, the greatest bubbling occurs out of the water and continues
> > >for up to four hours, not even peaking for a couple of hours. In a well
> > >vascularized, fit person like me, it is over with in 30 minutes. Don't bet
> > >on that with most of you.
> > >
> > >In ALL people, the bubbles continue to grow in size after the pressure is
> > >off. They accumulate like gas into themselves from the surrounding blood or
> > >tissues ( if there are bubbles in the tissues or injury sites ) and they
> > >grow bigger. This is why you feel pain later rather than earlier if the
> > >bubbles are in joints or tissues - they get bigger before they begin to
> > >shrink. This is why what starts out as micro bubbles can get by the lungs
> > >and grow and get lodged downstream, and you get neurological symptoms
later.
> > >
> > >Now here is the important part. If you understand everything I have said
> > >above, then you know that bouncing to 20 feet or whatever to pick up a
> > >bottle and immediately returning to the surface is the like giving yourself
> > >a home-made PFO: the bubbles in the venous side compress enough to get past
> > >the lungs and then will reexpand on the arterial side and lodge in the
worst
> > >places , the spine and brain blood supplies. You do not want this.
> > >
> > >If you dive after dive, stay down and let everything reset. Get the bubbles
> > >all compressed, and then deco out and ascend accordingly.
> > >
> > >I do not want support divers diving support within four hours of doing a
> > >real dive or deep support. This works out fine, since we have support
> > >activities lasting up to 18 to 24 hours and need to rotate everyone.
> > >
> > >Let me assure you that we have found this out the hard way in the past.
> > >Parker used to get hot as hell when it would happen. In those days we had
> > >"volunteers", and they would all get bent diving to 20 feet to pick up
> > >bottles. We have also seen some severe cases of this where dives were done
> > >away from the project with no support, and the players went back for
bottles
> > >later and got hammered.
> > >
> > >Don't do it. Also, obviously, do not freedive after a dive. When you want
to
> > >freedive, do that first and then go scuba diving.
> > >
> > >Any questions from WKPP guys?
> > >
> > >--
> > >Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> > >Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
> > >
> > >
> >
> > Simon
> >
> > Simon L Hartley
> > RSM Website Coordinator\First Year Course Coordinator
> > Associate Lecturer
> > School of Environmental Science and Management
> > Southern Cross University
> > P.O. Box 157
> > Lismore NSW, Australia 2480
> > Ph: (02) 66203251 or (61 66) 203 251
> > Fax:(02) 66212669
> > E-mail: shartley@sc*.ed*.au*
> >
> > http://www.scu.edu.au/schools/esm/staff/pages/shartley/
> >
> > http://www.scu.edu.au/schools/esm/
> > --
> > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
> 
> --
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