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

[Diver-Drex]

Ok, Table 6 will do it. But we can agree that those exposures are well outside normal recreational diving?
So the point being discussed in this thread is that breathing EAN to prevent DCS during recreational dives doesn't make sense because of the risk of pulmonary toxity. The fact that the treatment for DCS is O2 at over twice the accepted max ppO2 is hardly helping that argument. I would say that it clearly indicates exactly the opposite. O2 at concentrations above 21% as a way to decrease the nitrogen level in the breathing gas is an excellent counter to the affects of inert gas loading, both prophylacticaly and as treatment. And that it is so effective that the risks associated with it, CNS and pulmonary toxicity, are readily accepted. It has its limitations and cautions, but it works.
I've known this to be the case for 30 years, I'm not sure what has changed. I'm open to new information to bring into question EAN use, it just hasn't been brought up here.

 

[CuzzA]

I got through the first three pages of this thread and concluded that some still believe Nitrox is voodoo gas. If I missed something important please let me know.

 

[tursiops]

So the point being discussed in this thread is that breathing EAN to prevent DCS during recreational dives doesn't make sense because of the risk of pulmonary toxity.

I'd say it is not exactly a discussion. Rather, it was an off-the-wall, unjustified assertion, an opinion, that has been strongly disagreed with. The assertion would seem to be that if something is dangerous if taken to extremes, then one should never partake of it in any amount. Aside from being a logical fallacy, it is a bad idea to promote this attitude. Drinking too much water will kill you! So, we should drink no water at all, because of this danger?

 

[Diver-Drex]

Agree with both posts above. The assertion was baseless at best. I only know what I know, so I'm always willing to listen to something new or something that challenges the norm. Nothing was presented here that warrants further discussion.

 

[DiverDownD3]

 

[tarponchik]

Ok, Table 6 will do it. But we can agree that those exposures are well outside normal recreational diving?
So the point being discussed in this thread is that breathing EAN to prevent DCS during recreational dives doesn't make sense because of the risk of pulmonary toxity.

No, you missed the point again. The point here is that breathing EAN not to prevent DCS during recreational diving but just for the heck of breathing EAN doesn't make sense.

I've seen 3 arguments here for breathing EAN just for the heck of it:

1. Because it is available. This argument is irrational, so is not worth discussing. As for the price, my estimate is that diving NITROX adds on average about 5% to you diving cost (for example, $150 on our Aggressor trip, etc). This makes it certainly non-negligible in mathematical sense; whether this is negligible or not in economic sense is up to you to decide.
2. Because it feels good. I disagree with this one based on my personal experience. I suspect that, most likely, the believers fell into the trap of small numbers statistics. They got tired once diving on air for some unrelated reasons, then felt good next time diving on NITROX and came to wrong conclusion. However, it is entirely possible that there are indeed 2 kinds of people who respond differently to EAN. If this is so, this can be proved in a double-blind trial. Fatigue can be actually measured, not just felt, so there should be no problems running such trial.
3. N2 bubbles formed during recreational (rec) diving, even w/o DCS symptoms, are still harmful and result in tissue stress. So breathing NITROX reduces this effect. Well, if this is so, there should be some stats on negative effect of rec scuba diving on human health by now. Also, tissue stress has its markers that can be measured but no such data exist so far for rec divers.

 

[DevonDiver]

3. N2 bubbles formed during recreational (rec) diving, even w/o DCS symptoms, are still harmful and result in tissue stress. So breathing NITROX reduces this effect. Well, if this is so, there should be some stats on negative effect of rec scuba diving on human health by now.

1. There are studies showing that nitrox reduces post-dive bubble scores.

2. There are studies showing that micro-emboli trigger immuno-response and also that they can cause brain lesions.

See the linked articles in my previous post. Not sure why you're ignoring the references given to you, then denying, or claiming ignorance of, the existence of such knowledge resources.

Long term and/or indirect health impacts simply don't feature in current decompression science. Anything 'sub-clinical' is pretty much uninvestigated. The modelling and primary research is entirely focused on preventing clinically diagnoseable DCS... and nothing more.

Medical science (non-diving) has done plenty of research into the impact of micro-emboli....as it can feature in certain surgical procedures.

There's no practical difference between bypass cavitation induces micro-emboli and hyperbaric micro-emboli.... except that hyperbaric micro-bubbles have the capacity to be much higher frequency and more systemic/less localised.

 

[Neilwood]

I got through the first three pages of this thread and concluded that some still believe Nitrox is voodoo gas. If I missed something important please let me know.

If you breathe it you will die especially if diving in a poodle jacket with split fins.

 

[Storker]

If you breathe it you will die

...eventually

 

[tarponchik]

1. There are studies showing that nitrox reduces post-dive bubble scores.

2. There are studies showing that micro-emboli trigger immuno-response and also that they can cause brain lesions.

See the linked articles in my previous post. Not sure why you're ignoring the references given to you, then denying, or claiming ignorance of, the existence of such knowledge resources.

Long term and/or indirect health impacts simply don't feature in current decompression science. Anything 'sub-clinical' is pretty much uninvestigated. The modelling and primary research is entirely focused on preventing clinically diagnoseable DCS... and nothing more.

Medical science (non-diving) has done plenty of research into the impact of micro-emboli....as it can feature in certain surgical procedures.

There's no practical difference between bypass cavitation induces micro-emboli and hyperbaric micro-emboli.... except that hyperbaric micro-bubbles have the capacity to be much higher frequency and more systemic/less localised.

I am not ignoring your references; it is just that these are not direct references to scientific research. Moreover, one of your references states that "It is well proven in multiple studies that all divers develop small bubbles in their body after diving, but these micro-bubbles (also known as "silent bubbles") are insufficiently large to cause us significant, immediate harm", which is exactly my point. Also, I haven't seen any references that such bubbles can trigger immune response.

Your other reference deals a lot with "diver fatigue", treating it as a well established fact, based on your personal experience. So my experience is different than yours, can you get this finally? I do not feel "sleepy or listless" after diving, and I do not see any rational reason why I should.