In the absence of clinical signs or symptoms, after a blowup from 220,
I would be inclined to make the decision based on what my bottom time
had been - but again this is a judgement call.  I'd probably be
inclined to go to 5/4 of the violation depth and resume as before,
unless I had been down a while and was really worried, in which case
I'd throw on the FFM and go on oxygen.  Your 25 foot compromise sounds
like a good general guideline - perhaps 30 to 20 feet depending on the
accumulated oxygen dose during the dive?  In either case I would want a
KMB28 or some sort of manifold to accomodate gas breaks on the FFM.

-Sean


On Wed, 16 Feb 2000 14:27:52 -1000, Richard Pyle wrote:

>
>Hi Sean,
>
>> To get a bit more specific, assume your buddy has a problem that
>> requires you to accompany him to the surface to hand off to medical
>> attention, but then you are asymptomatic and can return to depth
>> immediately (say, one minute or less surfaced).  This actually happened
>> to me once.  What I did, after notifying the surface of my intent, was
>> return to 5/4ths of the violation depth, and then resume the deco
>> profile from that point with no extension of stop durations, other than
>> the oxygen stop (6m) which I extended by 50%, still including breaks to
>> back gas.  A safety diver came down to monitor me, and brought extra
>> oxygen, although I only used what I was already carrying.  Got out
>> feeling fine, apart from a bit of fatigue, as if I had done the dive on
>> air  (sub-clinical DCS?).  Does this approach sound reasonable, or do
>> you have a well defined reason to extend the non O2 stops as you
>> suggested?
>
>No, I think that sounds perfectly reasonable to me.  Anyone who thinks they
>have a "more correct" approach is suffering from "Sheila Syndrome".  There
>would be lots of other ways to do it that are likely equally reasonable.
>There is an interesting case of a diver doing an explosive ascent to the
>surface from 220 or so, who opted for a modified Australian IWR (modified in
>only descending back to 20 feet, instead of 30 feet), rather than returning
>to the deeper ceiling that was violated (let alone deeper than the initial
>violated ceiling).  This was done even though no symptoms were encountered
>prior to IWR. The outcome was reasonably good (apparently some minor
>symptoms diagnosed upon later reaching the chamber).  The point is, despite
>the vast variety of responses to symptoms (IWR) and aniticipation of
>symptoms (omitted deco), the vast majority of such attempts seem to do more
>good than harm.  There simply isn't enough reliable, controlled data out
>there to be any more precise.
>
>Hope that helps!
>
>Aloha,
>Rich


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