Tissue stress associated with bubble formation; potential benefits of diving enriched air

[tarponchik]

And just for the record tarponchik's profile lists gender as male?

I do not care much what this bunch of old f@rts call me but thanks for not misspelling my username.

Also for the record, I won't argue with NITROX addicts. I gave my opinion, that is it. The only documented benefit of using NITROX is in longer bottom times. If you do not use it to have longer bottom times (or shorter surface intervals, etc) you waste your money and (maybe) subject yourself to unnecessary oxidative stress. But this is your choice.

 

[uncfnp]

I do not care much what this bunch of old f@rts call me but thanks for not misspelling my username.

Also for the record, I won't argue with NITROX addicts. I gave my opinion, that is it. The only documented benefit of using NITROX is in longer bottom times. If you do not use it to have longer bottom times (or shorter surface intervals, etc) you waste your money and (maybe) subject yourself to unnecessary oxidative stress. But this is your choice.

Not true. At least not entirely. As a diver with a PFO I have a medical recommendation to dive nitrox, not for longer bottom times but as an added safety measure. I can't quote research but I can list the diving specialist, both lay and medical, that concur with this advice.

 

[Diver-Drex]

Whoa, you require a peer reviewed paper from me but give me this BS about "tissue stress" w/o any reference whatsoever? As far as I know, tissue stress is nothing but a theory. I do know, however, what oxidative stress is. Here is a peer reviewed paper on simulated diving with air and NITROX. They show that FMD response was significantly reduced in EAN divers only. This is a sign of oxidative stress. I do not know how bad this actually is but I do not want it because it is still bad.

As for the NDL, no question that NITROX is beneficial here but for me this benefit is obvious only in, say, Bonaire where I can dive myself off to the limit. There diving on NITROX pays off.

The findings of the UPenn study are the standard of care for the patient population it is relevant too, premies. The article presented the research completely out of context. There is no relevance to SCUBA.
Also, if you're that concerned why would you have asked for a cylinder filled with enrich breathing gas?

 

[tarponchik]

Not true. At least not entirely. As a diver with a PFO I have a medical recommendation to dive nitrox, not for longer bottom times but as an added safety measure. I can't quote research but I can list the diving specialist, both lay and medical, that concur with this advice.

I googled it:

A number of retrospective studies have established that the incidence of PFO is two to six times greater in divers who experience a neurological DCS hit; however, these studies do not prove PFO is the cause of DCS symptoms. The only prospective study designed to measure how PFO affects the risk of DCS is ongoing.

I did not know this, thanks for the information. I was speaking from the perspective of average diver, of course. But at least they have a theory how this is supposed to work.

 

[tarponchik]

Not true. At least not entirely. As a diver with a PFO I have a medical recommendation to dive nitrox, not for longer bottom times but as an added safety measure. I can't quote research but I can list the diving specialist, both lay and medical, that concur with this advice.

I googled it:

A number of retrospective studies have established that the incidence of PFO is two to six times greater in divers who experience a neurological DCS hit; however, these studies do not prove PFO is the cause of DCS symptoms. The only prospective study designed to measure how PFO affects the risk of DCS is ongoing.

I did not know this, thanks for the information. I was speaking from the perspective of average diver, of course. But at least they have a theory how this is supposed to work.

 

[tarponchik]

The findings of the UPenn study are the standard of care for the patient population it is relevant too, premies. The article presented the research completely out of context. There is no relevance to SCUBA.

What study are you referring to?

Also, if you're that concerned why would you have asked for a cylinder filled with enrich breathing gas?

Because there was a chance that otherwise I would reach NDL before other divers in the group did. If not on this dive, then on the next one.

 

[tarponchik]

Not true. At least not entirely. As a diver with a PFO I have a medical recommendation to dive nitrox, not for longer bottom times but as an added safety measure. I can't quote research but I can list the diving specialist, both lay and medical, that concur with this advice.

On 2nd thought, you are still using NITROX to get longer bottom times. In your case, it is suggested that NDL can be reached sooner than normally, so you have to either dive on NITROX or cut bottom time. At least, this is my understanding of the article I found.

 

[uncfnp]

On 2nd thought, you are still using NITROX to get longer bottom times. In your case, it is suggested that NDL can be reached sooner than normally, so you have to either dive on NITROX or cut bottom time. At least, this is my understanding of the article I found.

The idea is to dive nitrox on air tables so there's no longer bottom dives then air dives. I modify this a bit by diving the highest percentage nitrox (best mix) for the dive with the most conservative settings on my dive computers. So I do a blend of slightly longer bottom times compared to air but much shorter bottom times for the same mix on more liberal dive computer settings. The algorithm I use also tries to incorporate other factors that theorist believe may play a role such repetitive dives, short intervals, skipping stops...

 

[Diver-Drex]

What study are you referring to?

Because there was a chance that otherwise I would reach NDL before other divers in the group did. If not on this dive, then on the next one.

You posted a link to an article in Scientific America. That article referenced two studies, one was conducted at UPenn. Curious if you read the article before you linked to it?
So EAN reduces inert gas uptake and increases NDL times. It obvious that if you dive two dives with the same profile, one breathing air and one breathing EAN, the dive with EAN would have less inert gas loading and less decompression stress. So EAN can increase bottom time or increase safety, both a result of decreases inert gas loading.
So isn't that a pretty compelling reason to breath EAN even if you aren't trying to get more bottom time? I learned that back in 1985, but I'm just an old fart

 

[Diver-Drex]

Do you not think that divers experience decompression injury without getting treatment? Its not even in question whether or not reducing inert gas loading means less decompression stress. A good way to reduce inert gas loading is to use EAN.
If the incidence of treated DCS is 1% on air and on EAN it's .5% that's a nice increase in safety. It's 1 case in 100 dives for air dives and 1 in 200 for EAN. I'd say that's pretty good.