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Here's George's old reply to my IWR questions. There is more info in this
than I posted last time. I hope we can get a really good thread going
here, similar to that sample deco dive thread a while back.
>
> Hi George,
>
> All that bullshit about purging a victim has got me curious about IWR,
> especially in remote places. What protocol should be used for:
>
> 1) Omitted deco with no symptoms
> 2) Omitted deco with symptoms
> 3) Completion of deco, but symptoms are showing
>
> I have a ton of other questions about deco. Should I be asking you, or
one of the other WKPP guys?
>
> thanks
Before I forget, the guys to ask are Bill Mee , JJ, myself, and many
of the others, but their having the time to respond may be limited.It
depends on how tough the question is. They all ( the WKPP divers ) know
how to do deco. The farther out the scale you get , the more it is a
Bill Mee question.
To answer the above, let's first start with a couple of assumptions,
and then break it up a little. Let me get Karen's permission for this,
and have her check in her girl scout book for the proper legal
ramifications first, or we can just go on and take our chances here.
She can then tell me a better way that she has never had any experience
with once she has time to research this and straighten me out.
The first assumption is that the worst thing the "omitter" has
effectively done is move up the last 20 feet and out of the water too
fast. By this I mean that if any of us do this at any point in any deco
proper or improper, we are foaming out that last pressure gradient that
NO amount of deco will remove. Only a slow ascent to the surface will
allow that last bit of gas to come out in solution. Jumping up 20 feet
will bring it out in bubble form, no matter what.
So now the guy is out and foaming, but only the doppler knows this -
he is asymptomatic. We know from our doppler experience and endless
studies that this bubbling will actually INCREASE with time after the
diver is out of the ater, and will peak some 20 minutes to an hour
later, and hold at that level for up to hours.
Note - in our divers, especially me, the opposite occurs -the
bubbles are totally gone in 30 minutes. This may make some of the divers
out there want to consider the merits of physical fitness as it applies
to their diving, and to consider that a well-executed decompression
leaves a minimum of gas from which bubbles can form and grow later -
fact of life.
Now, we have two choices - do nothing ( which includes breathing
oxygen on the surface ), or tell him to go back and do some deco , and
then ascend slowly. I would go back and do the deco. But now we have
another problem. If he suddenly overwhelms his lung filter and takes a
CNS hit either by shunting in the capillary beds of the lungs or by the
increased right over left pressure caused by the bubbles in those beds
forcing open a PFO, he will not be safe by himself, and could convulse
or black out. A good buddy could get him back up, square him away and
find a way to get him back down, but now he really needs oxygen .It
starts getting complicated. I would still do it, but it takes two or
more divers .
If you had a full face mask, and oxygen, then it gets easier, but
then we are talking no suspect here to start with, right? But if he is
now getting bent ( questions two and three), then we move on and act for
sure. If we have the other equipment, then we are ready for more serious
solutions and have done more serious dives to require this, or we have
just not done it properly but have the tools to correct it.
Now we have to look at the profile - how deep , how long, how
serious could this omission be? How deep do we have to get this guy to
reduce the bubbles to where we can get them into solution or at least
managable enough to offgas through the lungs or get small enough to pass
by way of the circulatory system to the lungs where we can work on them
with oxygen.
Generally, if you can keep the guy alive, and stay on him, and that
goes for a may-be-nothing situation to a real blowout, getting him down
and getting him on oxygen ( or the correct max PPO2 gas for the depth)
are both a must if he is going to not be brain damaged.
The general best bet in the three situations you describe are to
take your chances by going back in, finding the starting point that is
reaonable and will not take to long to ascend from, and redoing that
part of the deco, with special emphasis on taking the last 30 to 20 feet
very slowly all the way up. Paralysis and other situations need to be
recomprssed and with a high PPO2 involved and more than one buddy . I
would hold them there until the Coast Guard or Helicopter ambulance
shows up and the chamber is lit and ready. If it were me, that would be
the way it would go. Acting fast on a screwed up deco can prevent things
getting this far out of hand. Occasionally, however, you are going to
get a person with a PFO or other shunt who will build bubbles after a
dive and go down on you well after he is long out of the water, and then
you have a real tough call. We now he need oxygen, but will
recompression do any good? Actaully, yes, and it it s very likely that
it will not take much more than ten to twenty feet of depth to do it.
A usual caveat with in water breathing of high PPO2 gases is watching
for the tox, but again, we are talking buddy situations only - you NEVER
send a guy back to do his omitted deco or IWR without a buddy on him.
Pain hits are not so big of a deal as an annoyance and a dive trip
ruiner as they are not going to go away completely. For one, the bubble
traped most likely seeded much deeper , and only grew to pain size
later. You can tell the depth at which it shrinks when the pain goes
away, and do the math to figure how deep it reasonably cound have seeded
at. It is a waste of time to go back to that depth since the damage is
done and you will feel the pain of the damage long after the bubble has
been reabsorbed. The better bet is to reduce it somewhat and give it a
chance to diminish ( they generaly grow first, but you have
receompressed it somewhat) and then try to overcome it with oxygen in
the slow ascent. It ( the injury site) WILL still hurt, but you have
solved two problems - you have reduced the bubble , and you have gotten
oxygen to the injury site. These injuries are really not that big of a
deal, but they are annoying, and will recur if you keep insulting them,
just like any injury, and the body tends to shunt off the injury and
angiogenisis around the site takes place , putting smaller capillaries
in place to shunt the blood flow, and these tend to trap bubbles more
easily on the next occasion, and account for the repeated injury of the
same site as well as the proclivity to get wacked more easily and more
often - a pure fact of physiology. Best to do deco correctly to start
with.
I hope this helps as a starting point.
I will also say this - with any of these injuries, especially any
paresthesis , paralysis, weakness, or cns symptoms of any kind, the
hyperbaric oxygen administered repeatedly over an extended time frame,
as in for some time evey day, is a must, and the earlier on it is
administered, the better the chances of success. There are also drugs
you can carry that are meant for use with spinal and brain injuries, but
this is a different story, and I know we will hear from the weenies if
we drag that one out. I would not hesitate to use them myself, however.
This is a good enough beginning, I am sure there are plenty of people
who have something to say about this. Let's keep it to not attacking me
by the assholes and try to make this one productive for once.
--
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