O2 pre breathing before eep dive????

[sky50960]

Hi guys out there.
Before a planned deep dive, Would there be an advantage to surface PRE BREATHING PURE O2 for a while in order to wash out nitrogen.:froggy:

fa

 

[rcohn]

Pressure gradients will be so high on a deep dive that any advantage to reducing nitrogen saturation will be small. In other words, you will absorb nitrogen so fast (it's an exponential curve) that eliminating a small amount prior isn't very effective. Beter to save the O2 for after the dive to speed up decompression and minimize microbubble formation.

Ralph

 

[sky50960]

Well you hit it.
This was meeting my thoughts.
Of course the best way to use it is during deco stop a 6 meters or at surface for emergence use.

Thanks

Fa

 

[Dr Deco]

Dear sky:

Oxygen prebreathe has actually been attempted several decades ago for divers. In some cases, it gives a SMALL advantage. For an active SCUBA diver, this nitrogen washout effect would be quickly nullified at depth, as the other responder indicated. It is an interesting thought, however.

The one idea (also from several decades ago) that was a total ”bust” was the concept of mixing four or five gases so that none of them individually would be at a saturation level. Since none are supersaturated, some thought that bubble formation would not occur. Gases do not partition themselves however into 100% helium bubbles and 100% nitrogen bubble, for example.
It was based on faulty physical chemistry.

Dr Deco

 

[sky50960]

Thanks DrDeco for reply.

Never know that there might have been a little advantage doing that.

CiaoCiao