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>        Most interesting is an alegedly statistical link between PFO and
>neurological DCS. According to the article 50% of the divers treated at Duke
>for neruological hits had PFO.  PFO statistically according to the authors
>exists in 20% of the population.

I've been spouting off about my belief in the existence of a link
between DCS (especially what we'd term "undeserved" hits - i.e. within
the table limits) and PFO for roughly 18 months now, glad to see it's
finally being looked into.  The percentages I've heard quoted for PFO
are between 25-33% depending on where you draw the line (chronic or
acute), never as low as 20%.  Of course we must recognize that PFO
comes in greatly varying degrees, just like other problems (asthma is
one that fits the bill perfectly here).

In a previous discussion about PFO and dive tables I made the
statement that since the dive tables were developed with a cross
section of the population that included PFO, most likely the tables
were quite conservative for the majority (66-80%) of divers, depending
on what you believe the incidence of PFO is, which is why many people
can push and break the tables quite often with no ill results.  On
rec.scuba recently someone from the uk stated that accident statistics
showed a strong correlation between DCS and divers w/PFO (it was dated
7/21/95 by Anthony John Peacock - rmhiajp@uc*.ac*.uk*)

>Most divers that get bent 'within limits' are tested for PFOs.  Just glancing
>through the report suggests that PFOs are a major factor with 'within limits'
>DCI.

No, I think it would be interesting to attempt to correlate the date
of DCS hits *outside* of the table to see if there appears to be a
"wall" somewhere at which DCS incidence increases dramatically.  I 
realize that this is a multidimensional problem but it could potentially
show that indeed the tables very conservative for many divers.

-Carl-

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