Any reported cases of Ox Tox between 1.4 and 1.6?

[passeparici]

The funniest part is divers who think their deco efficiency is directly a function of ppO2, which is an incomplete comprehension of decompression theory.

Some of these will start oxygen flushing at 30ft / 9m because "it's easier to hit 1.6" when in reality they will be off-gassing better at 10 ft / 3 metres at a ppO2 of ~1.3

That's what I use to think... But actually you are wrong. If you have a deco gaz of 100% oxy it is better to stay at 6 meters with a ppO2 of 1,6. It has to do with oxygene window

 

[passeparici]

So for extended deco divers,

Is there a specific study showing that ppO2 1.6 (100%) + 'air' (trimix) breaks is better/safer than incorporating lower ppO2's, setpoints or oxygen deco blends (e.g. 80%, 50%) into the final stops?

Did I miss that in other threads?
That long list of NEDU studies in the other thread aren't available thru Rubicon anymore.

100% alternating with 18/45 breaks is suggested in other threads/agencies as more convenient than deploying/breathing down a 50% stage for some of the time to manage oxygen toxicity. Might have to manually program these into a planner to check...

Anyone disagree that for O2/CNS/gradient matters, 3 metres / 10ft is a safer final stop depth than 6 metres / 20 ft?

Anyone modifying their air break protocols based on whether they are forced to stay on oxygen at 6m/20ft (1.6) vs at 3m/10ft (1.3?)

Anyone on long CCR deco doing in-loop 'air breaks' (low setpoint/deco dil flushes?) Vs. periodic 'air break' bailouts?

Deco with a ppO2 of 1,6 at 6 m has been done for years and many many time without any problem. You still stay on a relatively low ppO2 and for not so long. If you plan for 2 hours or more deco time at this ppO2 you might try something a bit different but for "normal" deco (let's say between a few minutes to half an hour) I think most here are over thinking.
About the studies look for oxygene window

 

[nadwidny]

That's what I use to think... But actually you are wrong. If you have a deco gaz of 100% oxy it is better to stay at 6 meters with a ppO2 of 1,6. It has to do with oxygene window

Oxygen window is no longer a thing.

 

[nadwidny]

So for extended deco divers,

Is there a specific study showing that ppO2 1.6 (100%) + 'air' (trimix) breaks is better/safer than incorporating lower ppO2's, setpoints or oxygen deco blends (e.g. 80%, 50%) into the final stops?

Did I miss that in other threads?
That long list of NEDU studies in the other thread aren't available thru Rubicon anymore.

100% alternating with 18/45 breaks is suggested in other threads/agencies as more convenient than deploying/breathing down a 50% stage for some of the time to manage oxygen toxicity. Might have to manually program these into a planner to check...

Anyone disagree that for O2/CNS/gradient matters, 3 metres / 10ft is a safer final stop depth than 6 metres / 20 ft?

Anyone modifying their air break protocols based on whether they are forced to stay on oxygen at 6m/20ft (1.6) vs at 3m/10ft (1.3?)

Anyone on long CCR deco doing in-loop 'air breaks' (low setpoint/deco dil flushes?) Vs. periodic 'air break' bailouts?

Does anyone do deep enough/long enough OC trimix dives to justify air breaks? I doubt it.

I do not do "air breaks" on my CCR. 1.3 setpoint. I might spike it to 1.6 at 70' for a bit. Old habits die hard.

 

[passeparici]

Oxygen window is no longer a thing.

Really ? I would like to have your sources on that because I heard otherwise

 

[Nick_Radov]

About the studies look for oxygene window

Could you give a specific citation for those studies?

 

[tursiops]

Oxygen window - Wikipedia

en.wikipedia.org

The effect of hyperbaric oxygen on the oxygen window | GUE

www.gue.com

The oxygen window and decompression bubbles: estimates and significance - PubMed

The "oxygen window" causes a partial pressure difference of inert gas between the inside and outside of decompression bubbles. Estimates of Po2 and Pco2 in tissue are necessary for O2 window calculations and any calculations about growth or decay of decompression sickness bubbles, but the...

pubmed.ncbi.nlm.nih.gov

Oxygen Window

The oxygen window first was described by Momsen, Behnke, Thalmann, Van Liew and Sass in the mid-twentieth century. They picked up the already described phenomenon of the undersaturation of blood compared to air at ambient pressure by Krogh at the beginning of the...

link.springer.com

 

[tursiops]

That long list of NEDU studies in the other thread aren't available thru Rubicon anymore.

It is really sad that Rubicon is gone, but here is some of the material that was listed.

https://www.tandfonline.com/doi/epdf/10.3109/01902148809064182?needAccess=true

 

[inquis]

If you have a deco gaz of 100% oxy it is better to stay at 6 meters with a ppO2 of 1,6. It has to do with oxygene window

The majority of that research is concerned with breathing something other than pure O2. The GUE article, to which @tursiops was kind enough to link above, eventually gets to the pure O2 case with these takeaways (IMO):

• Furthermore, inert gas elimination is independent of depth during oxygen breathing.

Cool, so the oxygen window does nothing in this regard. Based on this alone, 3 or 6 meters on O2 is arbitrary.

• Breathing oxygen at a deeper depth has the advantage of a greater hydrostatic pressure to hold dissolved gas in solution.

Yep, everyone knows this, it's integral to all the deco algorithms, and it has nothing to do with the oxygen window. Indeed, the final stop for most ocean dives is at 6m due to less impact by surface conditions. The primary drawbacks are pulmonary stress reducing the efficacy of inert gas transport, faster CNS loading, and increased consumption.

So it may be better to stay at 6m in some cases (e.g., wavy conditions), while it may be better at 3m in others. Pick your poison, but the O2 window doesn't figure into it in my view.

 

[passeparici]

The majority of that research is concerned with breathing something other than pure O2. The GUE article, to which @tursiops was kind enough to link above, eventually gets to the pure O2 case with these takeaways (IMO):

• Furthermore, inert gas elimination is independent of depth during oxygen breathing.

Cool, so the oxygen window does nothing in this regard. Based on this alone, 3 or 6 meters on O2 is arbitrary.

GUE says that in this article but that doesn't settled the matter. Most other researches say otherwise.

Also I would still like to see something about "oxygene window is no longer a thing".