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Once again, everything I said was ignored by you so you could present the
usual argument that what I do only works in caves on record dives done my me
only. Read the whole thing again. You are not listening, you just want to
argue, and I am not about to waste my time doing that.
Read it again.
-----Original Message-----
From: David Jacobs [mailto:jda@me*.co*]
Sent: Thursday, February 07, 2002 5:13 AM
To: techdiver@aquanaut.com
Subject: Re: WHY WE DO NOT BOUNCE DIVE
Hi George,
If my understanding is correct, the purpose of "bubbling" is to reduce the
total in water decompression time.
And I can see that it will give great advantages for the long cavedives
you do with hours of decompression;
but I was wondering if this is also practiced upon when doing those
relatively short open water (bounce) dives.
Lets say 30mins at 60m. (200ft.)
Doesn't the increased risk of bubbles outweigh the gained benefit in time
for "recreational technical divers" on those dives?
As you know all the training agencies from recreational to technical say
that bubbles are evil,
and I have a hard time accepting the fact to intentionally bubble at the
shallow stops.
as I think the slightest error will make the shit hit the fan
Isn't it safer to just hang a little longer and keep the gas into solution
as much as you can on dives where it is feasible?
And second: Bubbling in the bloodstream may be OK, but if you are bubbling
here; aren't you also bubbling in the tissues as well, because pressure is
equal everywhere; and so causing damage?
Please correct me where I'm wrong
Best,
David
At 09:07 AM 2/6/02 -0500, you wrote:
* If somebody wants to put that post on here, go ahead*
Here it is,
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.
----- Original Message -----
From: George Irvine
To: Techdiver@Aquanaut.Com
Cc: Cavers@Ca*.Co*
Sent: Wednesday, February 06, 2002 6:13 AM
Subject: deco posts , repets, etc. start with this
-----Original Message-----
From: George_Irvine@
Mike, I will put out my repet post and the others in sequence, but
first let me mention something here that is being missed.
Gas does not transfer from tissues into arteries or veins, it does so
into capillaries. The artilleries coming from the heart are huge, thick,
elastic , pulsing conduits that get smaller as they branch out until they
become capillaries, and then the return to the heart is through veins which
are also thick and get larger as they combine to return blood to the right
side of the heart.
That blood is then sent to the lungs, where the massive network of
tiny capillary beds located in about 45,000 square feet of surface area, act
as a "filter" for bubbles. The "filtered" and now oxygenated blood which has
passed its co2 and other excess gasses to the lung space, goes back to the
heart to be pumper through the system again. The whole trip takes about two
minutes to happen.
You do not bubble into the arteries. If bubbles get into the arteries
it is because they passed the filter or were "shunted" over through a PFO in
the arterial walls, or because they were momentarily compressed enough
momentarily to get past the lungs and then reexpanded as the pressure
dropped prior to reaching the capillaries, in which case they lodge in the
smaller and smaller vessels and block them. This occurs in bounce diving, as
in doing a dive and then bouncing back down to retrieve something, like a
deco bottle. This is why we do not allow bouncing in the WKPP, and why we
require our support divers to stay out for 4 hours before diving shallow for
support.
* If somebody wants to put that post on here, go ahead*
Most people get the greatest rush of bubbles from the tissues into the
blood stream upon surfacing from 20 feet or so. This is why we do that
differently, post to follow. Most people tend to bubble for hours after a
dive. Most bubbles tend to grow from the surrounding supply of gas before
they get smaller and disappear.
If the bubbles are in the tissues, yo have pain. The way to prevent
bubbles in the tissues is to properly decompress starting deep and at a rate
that allows the bubbles to escape to the blood stream. Deep this needs to be
done carefully and in solution, shallow you can press the gradient and allow
offgassing in bubble form into the blood stream. The difference is that if
you screw up shallow, you can go back a little and fix it. If it occurs
deep, that makes it impractical and a huge waste of time for nothing. For
people wight cardiac or pulmonary shunts, offgassing in bubble form is super
dangerous. For those without, it is far more efficient. For those with
PFO's, the risk is greatest AFTER they get out of the water for the reasons
stated above ( growth of bubbles and continuation of bubble offgassing)
I think you can see where I am going to tell you that you need to do
your shallowest dives first, do your drills before yo do your dives, and why
you can basically ignore repetitive dives using the correct deco. You can
NOT ignore them with respect to oxygen exposure.
This post is long enough , basic enough and preliminary enough. Now we
can go on to the whole bit.
-- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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<DIV><FONT face=3DArial size=3D2>Once again, everything I said was =
ignored by you so=20
you could present the usual argument<SPAN =
class=3D628032511-08022002></SPAN>=20
that what I do only works in caves on record dives done my me only. Read =
the=20
whole thing again. You are n<SPAN class=3D628032511-08022002>o</SPAN>t =
listening,=20
yo<SPAN class=3D628032511-08022002>u</SPAN> ju<SPAN=20
class=3D628032511-08022002>s</SPAN>t want to argue, and I am not about =
to=20
wast<SPAN class=3D628032511-08022002>e</SPAN> my time doing =
that.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><SPAN class=3D628032511-08022002><FONT face=3DArial size=3D2>Read
=
it=20
again.</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma><FONT=20
size=3D2><SPAN class=3D628032511-08022002><FONT face=3DArial=20
color=3D#0000ff> </FONT></SPAN></FONT></FONT></DIV>
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma><FONT=20
size=3D2><SPAN =
class=3D628032511-08022002></SPAN></FONT></FONT> </DIV>
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma><FONT=20
size=3D2><SPAN class=3D628032511-08022002> </SPAN>-----Original=20
Message-----<BR><B>From:</B> David Jacobs=20
[mailto:jda@me*.co*]<BR><B>Sent:</B> Thursday, February 07, 2002 =
5:13=20
AM<BR><B>To:</B> techdiver@aquanaut.com<BR><B>Subject:</B>
Re: WHY WE =
DO NOT=20
BOUNCE DIVE<BR><BR></DIV></FONT></FONT>Hi
George,<BR><BR>If my =
understanding=20
is correct, the purpose of "bubbling" is to reduce the total in water=20
decompression time.<BR>And I can see that it will give great =
advantages for=20
the long cavedives you do with hours of decompression;<BR>but I was =
wondering=20
if this is also practiced upon when doing those relatively short open =
water=20
(bounce) dives.<BR>Let=12s say 30mins at 60m. (200ft.)<BR>Doesn't the =
increased=20
risk of bubbles outweigh the gained benefit in time for "recreational=20
technical divers" on those dives?<BR>As you know all the training =
agencies=20
from recreational to technical say that bubbles are evil,<BR>and I =
have a hard=20
time accepting the fact to intentionally bubble at the shallow =
stops.<BR>as I=20
think the slightest error will make the shit hit the fan<BR>Isn't it =
safer to=20
just hang a little longer and keep the gas into solution as much as =
you can on=20
dives where it is feasible?<BR><BR>And second: Bubbling in the =
bloodstream may=20
be OK, but if you are bubbling here; aren't you also bubbling in the =
tissues=20
as well, because pressure is equal everywhere; and so causing=20
damage?<BR><BR>Please correct me where I'm=20
wrong<BR><BR>Best,<BR>David<BR><BR><BR>At 09:07 AM 2/6/02
-0500, you=20
wrote:<BR>
<BLOCKQUOTE class=3Dcite cite type=3D"cite"><FONT face=3Darial =
size=3D2>* If=20
somebody wants to put that post on here, go ahead*</FONT><FONT=20
face=3D"Times New Roman, Times"> </FONT><BR> <BR><FONT =
size=3D2>Here it=20
is,</FONT><BR> <BR><FONT face=3Darial size=3D2>WHY WE DO
NOT =
BOUNCE DIVE=20
AFTER DIVING IN THE WKPP</FONT><BR> <BR><FONT face=3Darial
=
size=3D2>It is=20
ok to offgas from the tissues into the blood stream in bubble form=20
in</FONT><BR><FONT face=3Darial size=3D2>the later steps of =
decompression as it=20
is a more efficient, faster way of</FONT><BR><FONT face=3Darial =
size=3D2>getting=20
rid of the remaining gas ( by reduced pressure ) than by=20
elevated</FONT><BR><FONT face=3Darial size=3D2>oxygen alone (
which =
starts=20
taking exponentially more time with greater</FONT><BR><FONT =
face=3Darial=20
size=3D2>risk) . However, this depends on having a good lung filter =
and no=20
shunts.</FONT><BR><FONT face=3Darial size=3D2>All of you have been
=
PFO tested if=20
you are diving with us.</FONT><BR> <BR><FONT face=3Darial =
size=3D2>The=20
correct way to ascend from the last stop is one foot per minute for=20
the</FONT><BR><FONT face=3Darial size=3D2>bigger=20
dives.</FONT><BR> <BR><FONT face=3Darial size=3D2>The
greatest =
potential=20
for offgassing in bubble form is when the pressure =
is</FONT><BR><FONT=20
face=3Darial size=3D2>totally removed back to one ATA out of the =
water. Now you=20
get a real shower</FONT><BR><FONT face=3Darial size=3D2>of bubbles
, =
relative to=20
what was happening in the water. A good , clean</FONT><BR><FONT =
face=3Darial=20
size=3D2>deco with the foot per minute ascent reduces this =
dramatically=20
.</FONT><BR><FONT face=3Darial size=3D2>In MOST people, the
greatest =
bubbling=20
occurs out of the water and continues</FONT><BR><FONT face=3Darial
=
size=3D2>for=20
up to four hours, not even peaking for a couple of hours. In a=20
well</FONT><BR><FONT face=3Darial size=3D2>vascularized, fit
person =
like me, it=20
is over with in 30 minutes. Don't bet</FONT><BR><FONT face=3Darial
=
size=3D2>on=20
that with most of you.</FONT><BR> <BR><FONT face=3Darial =
size=3D2>In ALL=20
people, the bubbles continue to grow in size after the pressure=20
is</FONT><BR><FONT face=3Darial size=3D2>off. They accumulate like
=
gas into=20
themselves from the surrounding blood or</FONT><BR><FONT =
face=3Darial=20
size=3D2>tissues ( if there are bubbles in the tissues or injury =
sites ) and=20
they</FONT><BR><FONT face=3Darial size=3D2>grow bigger. This is
why =
you feel=20
pain later rather than earlier if the</FONT><BR><FONT
face=3Darial=20
size=3D2>bubbles are in joints or tissues - they get bigger before =
they begin=20
to</FONT><BR><FONT face=3Darial size=3D2>shrink. This is why what =
starts out as=20
micro bubbles can get by the lungs</FONT><BR><FONT face=3Darial =
size=3D2>and=20
grow and get lodged downstream, and you get neurological symptoms=20
later.</FONT><BR><FONT face=3Darial size=3D2>Now here is the =
important part. If=20
you understand everything I have said</FONT><BR><FONT
face=3Darial=20
size=3D2>above, then you know that bouncing to 20 feet or whatever =
to pick up=20
a</FONT><BR><FONT face=3Darial size=3D2>bottle and immediately =
returning to the=20
surface is the like giving yourself</FONT><BR><FONT face=3Darial =
size=3D2>a=20
home-made PFO: the bubbles in the venous side compress enough to get =
past=20
the lungs and then will reexpand on the arterial side and lodge in =
the=20
worst</FONT><BR><FONT face=3Darial size=3D2>places , the spine and
=
brain blood=20
supplies. You do not want this.</FONT><BR> <BR><FONT =
face=3Darial=20
size=3D2>If you dive after dive, stay down and let everything reset. =
Get the=20
bubbles</FONT><BR><FONT face=3Darial size=3D2>all compressed, and =
then deco out=20
and ascend accordingly.</FONT><BR><FONT face=3Darial size=3D2>I do
=
not want=20
support divers diving support within four hours of doing =
a</FONT><BR><FONT=20
face=3Darial size=3D2>real dive or deep support. This works out =
fine, since we=20
have support</FONT><BR><FONT face=3Darial size=3D2>activities =
lasting up to 18=20
to 24 hours and need to rotate everyone.</FONT><BR><FONT =
face=3Darial=20
size=3D2>Let me assure you that we have found this out the hard way =
in the=20
past.</FONT><BR> <BR><FONT face=3Darial size=3D2>Parker
used to =
get hot as=20
hell when it would happen. In those days we had</FONT><BR><FONT =
face=3Darial=20
size=3D2>"volunteers", and they would all get bent diving to 20 feet =
to pick=20
up</FONT><BR><FONT face=3Darial size=3D2>bottles. We have also
seen =
some severe=20
cases of this where dives were done</FONT><BR><FONT face=3Darial =
size=3D2>away=20
from the project with no support, and the players went back for=20
bottles</FONT><BR><FONT face=3Darial size=3D2>later and got=20
hammered.</FONT><BR> <BR><FONT face=3Darial size=3D2>Don't
do =
it. Also,=20
obviously, do not freedive after a dive. When you want =
to</FONT><BR><FONT=20
face=3Darial size=3D2>freedive, do that first and then go scuba=20
diving.</FONT><BR> <BR> =20
<DL>
<DD>----- Original Message -----=20
<DD>From:</B> <A href=3D"mailto:girvine@be*.ne*">George =
Irvine</A>=20
<DD>To:</B> <A=20
href=3D"mailto:Techdiver@Aquanaut.Com">Techdiver@Aquanaut.Com</A>=20
<DD>Cc:</B> <A =
href=3D"mailto:Cavers@Ca*.Co*">Cavers@Cavers.Com</A>=20
<DD>Sent:</B> Wednesday, February 06, 2002 6:13 AM=20
<DD>Subject:</B> deco posts , repets, etc. start with
this<BR><BR>
<DD><FONT face=3Dtahoma size=3D2>=20
<DD>-----Original Message-----=20
<DD>From:</B> George_Irvine@</FONT><BR><BR><FONT
size=3D2>
<DD>Mike, I will put out my repet post and the others in sequence, =
but=20
first let me mention something here that is being missed.</FONT>=20
<BR><BR><FONT size=3D2>
<DD>Gas does not transfer from tissues into arteries or veins, it =
does so=20
into capillaries. The artilleries coming from the heart are huge, =
thick,=20
elastic , pulsing conduits that get smaller as they branch out =
until they=20
become capillaries, and then the return to the heart is through =
veins=20
which are also thick and get larger as they combine to return =
blood to the=20
right side of the heart.</FONT> <BR><BR><FONT size=3D2>
<DD>That blood is then sent to the lungs, where the massive =
network of=20
tiny capillary beds located in about 45,000 square feet of surface =
area,=20
act as a "filter" for bubbles. The "filtered" and now oxygenated =
blood=20
which has passed its co2 and other excess gasses to the lung =
space, goes=20
back to the heart to be pumper through the system again. The whole =
trip=20
takes about two minutes to happen.</FONT> <BR><BR><FONT
size=3D2>
<DD>You do not bubble into the arteries. If bubbles get into the =
arteries=20
it is because they passed the filter or were "shunted" over =
through a PFO=20
in the arterial walls, or because they were momentarily compressed =
enough=20
momentarily to get past the lungs and then reexpanded as the =
pressure=20
dropped prior to reaching the capillaries, in which case they =
lodge in the=20
smaller and smaller vessels and block them. This occurs in bounce =
diving,=20
as in doing a dive and then bouncing back down to retrieve =
something, like=20
a deco bottle. This is why we do not allow bouncing in the WKPP, =
and why=20
we require our support divers to stay out for 4 hours before =
diving=20
shallow for support.</FONT> <BR><BR><FONT size=3D2>
<DD>* If somebody wants to put that post on here, go ahead*</FONT> =
<BR><BR><FONT size=3D2>
<DD>Most people get the greatest rush of bubbles from the tissues =
into the=20
blood stream upon surfacing from 20 feet or so. This is why we do =
that=20
differently, post to follow. Most people tend to bubble for hours =
after a=20
dive. Most bubbles tend to grow from the surrounding supply of gas =
before=20
they get smaller and disappear.</FONT> <BR><BR><FONT size=3D2>
<DD>If the bubbles are in the tissues, yo have pain. The way to =
prevent=20
bubbles in the tissues is to properly decompress starting deep and =
at a=20
rate that allows the bubbles to escape to the blood stream. Deep =
this=20
needs to be done carefully and in solution, shallow you can press =
the=20
gradient and allow offgassing in bubble form into the blood =
stream. The=20
difference is that if you screw up shallow, you can go back a =
little and=20
fix it. If it occurs deep, that makes it impractical and a huge =
waste of=20
time for nothing. For people wight cardiac or pulmonary shunts, =
offgassing=20
in bubble form is super dangerous. For those without, it is far =
more=20
efficient. For those with PFO's, the risk is greatest AFTER they =
get out=20
of the water for the reasons stated above ( growth of bubbles and=20
continuation of bubble offgassing)</FONT> <BR><BR><FONT
size=3D2>
<DD>I think you can see where I am going to tell you that you need =
to do=20
your shallowest dives first, do your drills before yo do your =
dives, and=20
why you can basically ignore repetitive dives using the correct =
deco. You=20
can NOT ignore them with respect to oxygen exposure.</FONT> <FONT =
size=3D2>
<DD>This post is long enough , basic enough and preliminary =
enough. Now we=20
can go on to the whole bit.</FONT> </DD></DL></BLOCKQUOTE>
<DL></DL><FONT face=3D"Comic Sans MS"><BR></FONT>-- Send mail
for the=20
`techdiver' mailing list to `techdiver@aquanaut.com'. Send=20
subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.=20
</BLOCKQUOTE></BODY></HTML>
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