Chris-

Welllll, let's see here. Ah, here we go, Chapter 8 of Diving Medicine, some
tidbits of a very interesting (or maybe depressing) article:

"oxygen toxicity is caused by the production of free radical intermediates
in excessive concentrations during exposure to increased oxygen pressures"

"the pathological response of the lung to oxygen toxicity can be
differentiated into two overlapping phases of progressive deterioration. The
fires is an acute exudateive phase consisting of interstitial and alveolar
edema, intra-alvelolar hemorrhage, fibrinous exudate, hyaline membranes,
swelling and destruction of capillary endothelial cells, and destruction of
type I alveolar epithelial cells" (Christ that's just phase one)

"Changes in pulmonary function which have been measured in humans during and
after prolonged exposures to oxygen pressures of 1.0 at or higher include
decrements in inspiratory and expiratory lung volumes and flow rates, carbon
monoxide diffusing capacity, and lung compliance." (that's at 1.0, folks)

So, Chris, I don't think you can always measure damage by the number of
stiffs floating around in Her Royal Majesty's Waters. The question you have
to ask is fucking up your lungs permanently worth a few minutes of saved
deco? You are much better off exposing your lungs to the high PP02s when you
are at deco resting and can give your lungs low PP02 intervals from your
back gas. I think you high PP02 nitrox hounds ought to think things over a
bit more carefully.

   Jim
 -------------------------------------------------------------------
 Learn About Trimix at http://www.cisatlantic.com/trimix/

> From: Chris Stenton <jacs@gn*.co*.uk*>
> Date: Tue, 10 Oct 2000 19:26:26 +0100
> To: cobber@ci*.co*
> Cc: "dmdalton" <dmdalton@qu*.ne*>, dwiden@ho*.co*,
> donburke56@ne*.ne*, "'Paul Braunbehrens'" <Bakalite@ba*.co*>,
> techdiver@aquanaut.com
> Subject: Re: rec trimix
> 
> 
>> I know this is going to piss off a lot of rec divers but I believe that
>> increasing your bottom PP02's for the purpose of avoiding a deco obligation
>> is
>> a really stupid idea. It is typical of our sport that this principle is
>> embraced by almost everybody. Even to the point of calling potentially deadly
>> hyperoxic mixes "safeair".
> 
>> I think there should be an industry-wide ban of bottom or working PP02's of
>> anything over 1.2.
> 
> Jim,
> 
> Give us some statistics or physiology  to back this up. I haven't seen one
> report of a recreational "no stop dives" diving  death or oxtox hit attributed
> to using Nitrox at a ppO2 of 1.4 or below here in the UK.
> 
> Far more important surely is getting the people "at risk" out to do some more
> exercise. How about removing people cert cards who can't run a 6min mile; far
> more likely to reduce the work load of the emergency services than some
> arbitrary ppO2 limit of 1.2.
> 
> 
> Chris
> 
> --
> Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
> 


--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]