Nitrox and lung burnout?

[GP]

Uncle Pug once bubbled...
Take a look a Cobb's trimix website
http://www.cisatlantic.com/trimix/trimix.html

I am reposting my post here from another thread as it seems this is a more appropriate location.
I was checking this site out (the link above that Uncle Pug posted) and I am wondering about this little piece taken directly from the site regarding Nitrox: "Inflammation of lung tissue from long term exposure- You can calculate your exposure to minimize this, but reports are coming in from the field of "lung burn out" caused by high levels of 02 which are well under the standard limits." Could someone explain this a little better for me...how high of a level of O2 do you suppose he is reffering to...circumstances, etc to cause this?

 

[Dr Deco]

Dear GP:

Burnout?

I cannot say that I am aware of this in any detail. I do know that divers have reported problems with elevated oxygen when it was used repeatedly over many days.

Any others have experience here?

Dr Deco :doctor:

 

[Uncle Pug]

...what is being refered to here is pulmonary toxicity from high PO2s (or extended exposures to PO2s above .5 ATA.)

I also gather that the site is implying that there exists anecdotal evidence that commonly accepted exposure limits might be too high and that onset of pulmonary symptoms (accompanied by reduced efficiency) can occur at lower level/exposures.

The general idea to take away from this is that limiting O2 exposure is something to consider during the working portion of a dive when later decompression will require elevated PO2.

In other words... don't use high PO2 backgas mixes on deco dives where you will later be using EANwhatever or O2 to raise the PO2 to 1.6 during deco.

Also included in this is the idea of breaks to backgas during extended decos at high PO2 to allow the lungs to recover from the exposure and reduce the potential for pulmonary edema and thus regain efficiency.

Course I could be wrong... that's why I though you should ask Dr. Deco.

 

[Padipro]

I think Uncle Pug is right. It sounds like the author is just using different termonalogy.

Scott

 

[GP]

Thanks guys, I think I understand now.

 

[Dr Deco]

Dear Readers:

My thanks to Uncle Pug. This sounds like the information that recreational divers are seeking. "Air breaks" (or another inert gas) are a well-accepted method to reduce pulmonary and CNS oxygen toxicity.

Dr Deco.=-)