Mailing List Archive Mailing List Archive
>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'.
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]