O2 deco gas and asthma

[liamm]

Does anyone have any info they point m in the direction of regarding this?

I've spoken to my Doc and he "cant see an issue" but ive noticed it raised on a few websites - notably all quoting the same document (rant) from GI

I've used up to 80% without problems but the deco wasnt prolonged. Is there an issue of 100% irritating the lungs?

[MarkP]

Originally Posted by liamm

I've used up to 80% without problems but the deco wasnt prolonged. Is there an issue of 100% irritating the lungs?

Yes, high PO2 is inflamatory. Even a PO2 of 1 is an irritant and because of this even people breathing it on the surface take breaks from it on a regular basis.

As a diver, prolonged exposure compromises gas exchange.

I have no idea about the nature of an asthmatic's lungs and the nature of the irritation caused by high PO2.

See a doctor who knows about diving medicine.

[Clare Gledhill]

Oxygen irritates the lungs full stop - it's not the fact that you are asthmatic which will make this happen - it's the fact that you are a human and designed to breathe O2 at surafce pressures. See this, amongst many papers - it's not great but it is the first I googled and it sets out the basic facts.

http://medind.nic.in/jac/t03/i3/jact03i3p234.pdf

(B) Pulmonary toxicity – ‘Smith effect’

Pulmonary effects of oxygen toxicity can occur after
a prolonged exposure to oxygen > 0.5 ATA. Symptoms
appear after a latent period whose duration decreases
with increase in pO2. In normal humans, the first signs
of toxicity appear after 10 hours of oxygen at 1 ATA6.

Pathology and pathophysiology

Prolonged and/or high concentrations of oxygen may
damage the pulmonary epithelium, and inactivate the
surfactant, form intra-alveloar oedema and interstitial
thickening, and later fibrosis, leading to pulmonary
atelectasis5,11. The lung lesions resemble those of paraquat
poisoning12.

I have asthma and dive with extended period of O2 dceo when necessary. I follow unammended protocols on air breaks and have never had a problem.

[liamm]

Cheers Claire,
i guess this is something i'll have to build up to and just see how i feel afterwards.
Thanks for the link.
Liam

[Gene_Hobbs]

I'd post some references but I recently spent a few hours updating the Oxygen toxicity - Wikipedia, the free encyclopedia article so the references are available. It takes quite a while to develop symptoms of pulmonary toxicity. This is explained in the Clark and Hamilton references on that page. More articles can also be found in our suggested reading list but the Wikipedia gives context.

Please let us know if you need more after reading these. Good luck!