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Hi everyone,
Two things,

Anthony Appleyard wrote;
***quote***
In rebreathers, how dry does the absorbent make the breathed gas? On a long
dive does that often cause worse mouth dryness than is usual with aqualungs?
***end quote***

My understanding of CO2 absorbers is that they need some moisture to work
and so the loop should remain moist, particularly as you are rebreathing
your moist exhaled gas.  I haven't done enough time on a rebreather to
say from experience though (damn it).  I think the normal moisture is
about 10% but this is from memory, often hazy these days.

Subject 2,

Steve Hogan wrote
***quote***
...but if I felt symptoms coming on and the chamber is more than
1-2 hours away (depending on my condition) I would *probably* opt for
IWR also.
***end quote***

Kevin-Neil Klop wrote,
***quote***
...the coast guard could get to you in 1/2 an hour (because
they have a base nearby), but that it will be 1 + 1/2 hours before you can
enter a chamber (because the nearest available chamber is 1 + 1/4 hours
flight time and it takes 1/4 hour from landing to entry into chamber).
Should you have the helicopter standby (or not call them) and attempt IWR
instead?

I have a gut instinct that says "no".

***end quote***

Kevin's maths is a bit wonky here, he metions the 1/2 hour for the chopper
reach the diver, but then it disappears from the calculation again.  Small
point, it is a hypothetical (is that how you spell it) situation anyway.

The point I want to make is that a Hyperbaric unit in Australia has advised
me that the absolute minimum time required to assess a patient *before* they
can be placed in a recompression chamber is *One Hour*.  If you feel as
Steve does that a 1 or 2 hour delay would swing you toward IWR then you
may need to factor that in.  If you are in a situation like Kevin, 1/2 hour
to call a chopper (this is quite short, it takes a while to preflight them)
plus 1+1/4 hour flight time (1+3/4 hours) plus 15 minutes to load the diver
(2 hours) plus a 1 hour delay at the hospital you are faced with a
minimum 3 hour delay.  That minimum of one hour, advised by the hospital,
was if you called ahead, and the staff could be found to man (person?) the
chamber.  If not then they would need to come in from home, and set up the
chamber from scratch.

If you *know* of facilities that can recompress in a significantly shorter
time, please contact me, as I would like to pass this information on to
the management of the chamber in question.

Cheers Jason (Southern Hemisphere branch)  ;)

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