Hypothetical question

[dmaziuk]

Does your planet have cellular respiration converting oxygen to water constantly?

 

[markmud]

6 hrs. Just in case
In real - no need, because for this depth and time you will not obligate too much for slow tissues, and time to airport, than registration, etc - will over 3 hrs...
Above is just my NON specialist opinion, just personal estimation.

Hi Boulderjohn,

Microbubbles or not, I am with Anekca on this one (except for loading slow tissues; they will be off-gassing nitrogen).

@doctormike: What if a person breathed 100% O2 at the surface, same microbubble issue?

Or, 100% at 20 feet?

But they do exist, because you were exposed to a drop in ambient pressure.

So a drop in PP won't cause the same issue?

Thanks,
mm

 

[EFX]

S/he can fly immediately. After one hour on the surface breathing air the controlling TC 16 has only ongassed to 23.77 fsw. The dive started with all tissues saturated at 24.67 fsw at sea level breathing air. I used my spreadsheet to calculate the tissue loadings. Here is the screen shot:

 

[kotik]

I am with Anekca

Just a small FYI if you're going to shorten the name & Anglicise it, better make it "Alex"

I wouldn't personally be worried about flying after the dive described.

 

[tarponchik]

I keep wondering why diving 60% O2 is not so popular...)

 

[huwporter]

I can't find the cite anymore, somewhere on PubMed there's an old study that concluded that oxygen doesn't bubble nearly as much as nitrogen. I could never find much about how or why.

Edit of entire post since I found the study I was fuzzily half-remembering:

http://www.ultimatedivelog.com/articles/25.pdf

Study examines whether and to what extent oxygen may contribute to bubbles and/or DCS. Very simplified summary, oxygen can contribute to DCS symptoms in extreme situations (- situations more extreme than any normal dive practices would allow), but any 'oxygen-DCS' thus provoked rapidly self-resolves/self-treats as the oxygen bubbles are reabsorbed.

As far as the original hypothetical question goes, I'd personally climb on a plane with my hair still wet after that profile - but since the question actually asks what I'd say to someone else, then that would depend entirely on what my relationship with that person is. (I.e. with a stranger, my suggestion would be to follow their training or agency advice; with one of my tech buddies I'd have a different discussion.)

 

[doctormike]

@doctormike: What if a person breathed 100% O2 at the surface, same microbubble issue?

Or, 100% at 20 feet?

So a drop in PP won't cause the same issue?

Thanks,
mm

My understanding is that DCS risk associated with bubbling requires a drop in ambient pressure, not a drop in PPN2 with no change in ambient pressure. I do not think that switching from, say, air to 100% O2 at 20 feet is a risk factor for DCS, despite the rapid and large drop in inspired PPN2 and the resultant increased offgassing gradient.

If you breathe 100% O2 for long enough, eventually all of your tissue compartments will be free of inert gas. Once that happens, any reduction in ambient pressure (scuba ascent, air travel, explosive decompression due to loss of cabin pressure or spacewalk) will not put you at risk for bubble formation, since there is no inert gas to bubble.

 

[huwporter]

My understanding is that DCS risk associated with bubbling requires a drop in ambient pressure, not a drop in PPN2 with no change in ambient pressure. I do not think that switching from, say, air to 100% O2 at 20 feet is a risk factor for DCS, despite the rapid and large drop in inspired PPN2 and the resultant increased offgassing gradient.

I think inner ear isobaric counterdiffusion DCS https://www.physiology.org/doi/pdf/10.1152/japplphysiol.01090.2002 might be the only partial exception to the 'drop in ambient pressure' requirement, and this requires a switch from high-He gas mix to high-N2 gas mix part-way through a significant deco exposure. I don't think that switching to oxygen would have any such risk associated - happy to be corrected.

 

[Germie]

Fly.
When doing normal dives, even trimixdives, you can use surface oxygen and then also reduce the nofly time (but there is not a lot of research done on this).

 

[Storker]

If you breathe 100% O2 for long enough, eventually all of your tissue compartments will be free of inert gas. Once that happens, any reduction in ambient pressure (scuba ascent, air travel, explosive decompression due to loss of cabin pressure or spacewalk) will not put you at risk for bubble formation, since there is no inert gas to bubble.

Yep. And if the N2 pressure in your tissues is the same as it is on the surface, how likely is it that you'll bubble if you suddenly find yourself at the surface? There just isn't any driving force pushing the N2 out of solution. And if your N2 pressure after the dive is the same as if you'd canceled the dive and had a beer on the boat instead, how likely is it that you'll bubble during a flight?