On Wed, 16 Oct 2002 16:45:09 -0400, Michael Doelle
<[log in to unmask]> wrote:


>>>Look at the webpage you suggested below.  It's a GENERAL position
>to treat dive victims in ALL KINDS of (unknown) causes, from DCI to
>certain specific injuries.
>
>Treating injuries implies above water though. At which point offgassing is
>not really an issue.

Oh yeah?  I wonder why they administer oxygen to potential and actual
DCI victims.

Injury happens to be a tangential point of the discussion about the
MERITS of being in a horizontal position when doing deco or being
treated for injury.  If it's a Good Thing <tm>, it's a good thing
for the same physiological reasons, above ground or at shallow.


Changing topic to the MERIT of swimming around at safety stop,

>>Put it another way, it there is ANY MERIT to your theory about
>moderate exercise is good for off-gassing (during safety stop and
>right before surfacing), then why have we NEVER heard of any
>suggestion to EXERCISE MODERATELY as soon as you surface, ...
>in order to increase blood flow overall and for off-gassing.<

which was my response to Mika's comment, about at SAFETY STOP,
Mika> They're (unknowingly?) doing the right thing. Moderate exercise
Mika> is good for off-gassing, as it increases blood flow - overall
Mika> and through the lungs.

>The idea is to stimulate cardiovascular activity, i.e. increased blood flow
>through the lungs. Which aides gas exchange in the lungs. With the idea to
>prevent bubbling prior to/upon surfacing. And once you've surfaced, I don't
>see how moving around would be detrimental unless you were already showing
>symptoms. Isn't that what everyone does?

But in the case of no injury, why is off-gassing at the surface not
as important as off-gassing at safety stop?

>>Of course the latter "natural implication" (which you didn't
>mention of course) is equally BOLLOX, as the natural consequence
>of your assertion about off-gassing and blood flow at safety stop!<
>
>Blood flow through the lungs is irrelevant at the stops? I think I don't
>understand your point here.

Blood flow and everything ELSE are relevant at the stops, AND at the
surface.
>
>>THAT was the meaning of my "Bollox".<
>
>Which still escapes me.

I hope re-iterating my INTENDED point, which might have gotten lost
somewhere along the line, helps you catch whatever escaped.  ::-)


>>Swimming around is a frivolous exercise at safety
>stop, for no useful purpose whatsoever, ...
>
>There is ALWAYS a point to frivolous exercise ...

To useful exercise I would agree.  "frivolous exercise", no.  :-)
>
>>>... other than making it easier for the newbies to stay at a constant
>shallow depth of 15 feet
>
>... and I mostly ignore what most others do at their stops. Let them be
>negative and sink into the blue ...
>
>>And why would it at shallow?  Here I don't know (nor anyone else) the
>actual physiology of specific tissues or tissue groups, but at least
>according to the modeled compartments, ALL of the compartments
>on-and-off gas according to the same class of NEGATIVE exponential
>curves, of merely different rates (of half lifes or M-values).<
>
> Well, blood flow through the lungs is not irrelevant, that's where the gas
>exchange happens.  I'm not a goat sitting in chamber, nor do I have any
>compartments. The deco models do not (as of today) dictate what divers
>should do. It's the other way round. Divers still provide the input on what
>works, THEN the models are -constantly-  adapted to follow the experiments.
>Physiology is the input, the models follow. And much of it is still
>anecdotal, often maybe just dependent on individual experience.

Your slips are showing in your last paragraph.  There are a relatively
short ongoing threads in rec.scuba on "Perfusion, Modified Haldane
& Bulk Diffusion Models" which resulted after hundreds of posts on
dive computers, that will have CORRECTELY covered all your points
(and corrected your errors) about tissues, compartments, gas exchange
(diffusion) and blood exchange (profusion) by a lengthy web page
article by one Dr. Martin (in PLAIN English), and another PLAIN
English reference by someone else, even if you discount MY (plain
English) comments.  :-)  This neither the time nor place to go into
this one.

But the MAIN POINT you missed is that BLOOD exchange (perfusion) IS
an integral part of ALL dive computer algorithms.

>
>>>But the basic principles are the same --
>about proper weighting and neutral buoyancy and no wasted kick
>motions.
>
>I would not dream of disagreeing here.

Glad to hear that!  Then I don't understand why you seem to have
trouble understand my statement (about teh wasted kick) in

RF>Swimming around is a frivolous exercise at safety
RF>stop, for no useful purpose whatsoever, ...

But I think this is good time to bring this to a closure.  I think we
disagree on some scientific facts and implications, but we pretty
much agree on DIVE PRACTICE -- the most important of which (to ME) is
relaxation and good buoyancy control both of which significantly
contributes to SAFE diving, all other things being unequal.  :-)
>
>[descent, ascent]
>>Both of course!
>
>Yup, but you still owe me a pint of phycoplonk for mentioning me and Nick
>in the same sentence.

Mika and Nick in the same sentence ... hmmm ...

Mika, you are MUCH more intelligent and handsome and healthier (weighs
at least 150 lbs less) and less stubborn than Nick.

Do I now owe you TWO pints of phycoplonk, or NONE?   :-))
I need to know, to let Strike let Julian know how many extra pints
we'll need at the Strike Reef party.   :-))))

-- Bob.