How does deco diving affect health

[espenskogen]

Well you shouldn't cross the PO2 1.6 boundary. People are tending to lower the ceiling to PO2 1.4 now. All studies I've read state that the O2 toxicity starting point is PO2 1.6. This could differ from one diver to another. It differs also according to the physical status of the diver himself at this day.

85 metes on air is stupidly deep. However, I know people did 113 meters on air!!! Don't try this please. You promised

The Blue Hole is 120 meters deep. This is the deepest point under the arch. However, the outer side of the Blue Hole is said to be 300 meters deep.

O2 tox isn't something that will suddenly occur if you dip under a pp02 of 1.6 - You have a CNS O2 exposure limit, which rules how the pp02 affects you. Sure, it's variable in each individual what exposure you can take, but according to TDI, at a pp02 of 1.6 bar, you can handle about 45 minute exposure.

The lowest recorded instance of o2 tox WITHIN the CNS Exposure limits was at a partial pressure of 1.72. As long as you stay within the limits, there hasn't been any convulsions recorded at 1.6 or lower. It is however standard practice to plan for a pp02 of 1.4 for your bottom time, and 1.6 for deco.

(Although the US Navy operate emergency tables for up to 2.0 pp02)

If you want more detail, the TDI advanced nitrox course goes through this aspect of O2 exposure in great detail.

E

 

[karstdvr]

O2 tox isn't something that will suddenly occur if you dip under a pp02 of 1.6 - You have a CNS O2 exposure limit, which rules how the pp02 affects you. Sure, it's variable in each individual what exposure you can take, but according to TDI, at a pp02 of 1.6 bar, you can handle about 45 minute exposure.

The lowest recorded instance of o2 tox WITHIN the CNS Exposure limits was at a partial pressure of 1.72. As long as you stay within the limits, there hasn't been any convulsions recorded at 1.6 or lower. It is however standard practice to plan for a pp02 of 1.4 for your bottom time, and 1.6 for deco.

(Although the US Navy operate emergency tables for up to 2.0 pp02)

If you want more detail, the TDI advanced nitrox course goes through this aspect of O2 exposure in great detail.

E

I'm not sure I entirely agree with what is being said (no flame intended). The 45 minutes exposure limit is mathematical,with not a lot of research to back it up,and these numbers flutuate with other factors such as work load ie CO2 retention and medication ie Sudafed. I recall 2 incidences of toxing within a PP0s in the 1.4X region,but there were other factors that nobody can account for such as current and medication,but nobody knows to what degree. DAN a few years ago was fairly smart when they set their recommended level to 1.3,and quite a few cave divers have done the same. Conservatism when setting PPO2 is absolutely neccessary,a little more deco or less depth is a good thing compared to the alternative,because O2 toxing isn't a ride in the chamber,but a ride in a hearse.

 

[Red Sea Shadow]

O2 tox isn't something that will suddenly occur if you dip under a pp02 of 1.6 - You have a CNS O2 exposure limit, which rules how the pp02 affects you.


(Although the US Navy operate emergency tables for up to 2.0 pp02)

Sure. What I was saying is that one should start to worry at PO2 1.6. I referred to this as toxicity starting point.

Yes that's correct. US Navy operate emergency tables for up to PO2 2.0.

 

[wedivebc]

according to TDI, at a pp02 of 1.6 bar, you can handle about 45 minute exposure.

That is actually NOAA that studied and published that exposure limit. TDI just uses the data like every other agency.

The lowest recorded instance of o2 tox WITHIN the CNS Exposure limits was at a partial pressure of 1.72. As long as you stay within the limits, there hasn't been any convulsions recorded at 1.6 or lower.

That is an absolutely false statement. There have been cases below 1.6. Certain individuals are very suseptable to CNS toxicity and although rare they do exist. Not sure where your getting your "facts" from.

 

[espenskogen]

That is actually NOAA that studied and published that exposure limit. TDI just uses the data like every other agency.

As I said - it was according to TDI - I didn't claim TDI had made the studies.

That is an absolutely false statement. There have been cases below 1.6. Certain individuals are very suseptable to CNS toxicity and although rare they do exist. Not sure where your getting your "facts" from.

According to my TDI instructor, there has been cases under 1.6, but they've exceeded their exposure limits - If this is wrong, it would be good if you could substantiate the instances when this happened, so that I can communicate this on to my instructor and TDI.