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On 22 September 1999 21:05, Huw Porter wrote:
 
> A question (actually two) related to long thread on enriched air and
depth.
>
> a)  If a diver in an emergency at depth switched to a too-high-PPO2 mix,
> would the effects of oxygen toxicity kick in immediately or is there a
> brief period of 'grace' - and if the latter, what factors influence this?
 
Hi, Huw!  That's a 'Six-Million Dollar' question!  And the answer is:
Yes/No - and more factors than wot you can poke a stick at! :-)  (As far as
I'm aware there's still no formula for predicting when, where or why a
'hit'
will happen!  It's been suggested that CO2 build-up; diet; fitness;
emotional state; water temperature; work-load, etc. all play a role.)
 
The easiest answer is to say that even in the same individual, it varies
from day to day and situation to situation!  In terms of trialing it until
your luck runs out, it's probably on a par with Russian Roulette - with
three chambers loaded!  :-)
 
> b)  Does oxygen narcosis relieve immediately on ascent to an appropriate
> depth in the same way that nitrogen narcosis does?
 
In the case of oxygen toxicity, (in the case of O2, it's toxicity - not
narcosis!), it usually requires longer convalescence (Sp?) time - if you're
fortunate enough to survive!
 
Strike