Using O2 on NDL dives

[scububa]

I agree with BigBob that a 50% mix would be better. Alot less chance of taking an O2 hit, and you've got a bailout gas. With that said, I've seen about 300 people take an Oxygen Tolerance test 60' on 100% for 30 minutes and I've never seen a hit.

Were these in-chamber or in-water?

[Superlyte27]

Chamber

[PfcAJ]

There is a big difference between an o2 tolerance test in a chamber and o2 exposure while diving.

[Superlyte27]

Yup, I know, but not as big as the difference in diving 15' on O2 in the water and diving 100% at 60' in the chamber.
Point is, one is SIGNIFICANTLY more risky than the other. And on the riskier dive, i've never seen a hit, in 300+ people.

[Burke]

I wouldn't recommend using O2 on the surface post dive. If I see someone breathing O2 on the surface, I'm going to offer to call an ambulance or get DAN on the phone for them.

[Superlyte27]

If i've got a long hike to or from the water, like at Friedman, I'll breathe O2 for the hike. It seems to help. Might be all in my head.

[mfascuba]

I wouldn't recommend using O2 on the surface post dive. If I see someone breathing O2 on the surface, I'm going to offer to call an ambulance or get DAN on the phone for them.

So you've got 5~6 hours between Miami and Fort White - can you tell me you've never finished a day of diving and hit the road south with an O2 reg in your face, bottle between the front seats? I've done it - a few times. Makes for funny looks from other drivers!!

Mark

[Superlyte27]

I have, not exactly that drive, but Cave Country to Orlando, absolutely.

[TommyB]

So you've got 5~6 hours between Miami and Fort White - can you tell me you've never finished a day of diving and hit the road south with an O2 reg in your face, bottle between the front seats? I've done it - a few times. Makes for funny looks from other drivers!!

Mark

I do it when driving home from Eagles Nest- about 2 hr drive. And here I thought I was the only one. I've had people look at me funny and point.
But it does seem to make me feel a little better.

[JS1scuba]

Running a dive to the NDL limits has a slightly higher risk of DCS than a dive that required only a short amount of decompression time and that time is completed. Supplementing a full no-stop dive with an elevated oxygen content mix is quite helpful.

For example. (using USN tables for discussion)

Let's say you do a 90 foot dive for 45 min using EAN 32. This gives on USN a no stop time of approx 45 minutes. And you cannot fly after this dive for 12 hours. If we add in just 5 minutes of breathing 100% oxygen at 15 feet the divers new "ceiling" is now 4000 foot mean sea level (or can ascend up 4000') extend that 5 minutes to 10 minutes and now the new ceiling is 5000'. Do the same profile and use EAN 50 instead of 100% and your new post dive ceiling is only 3000'. (logical).

If you get out of the water and breath 100% oxygen for 10 minutes on the surface after a 5 min air surface interval (getting out of gear) and you can push the ceiling up to 4000' msl. (similar result)

I've long been a proponent of "padding with gas" adding a little oxygen after the schedule has been completed or after the dive computer has cleared. The benefits are clear when it can be done in a benign environment.


Consider it oxygen as a prophylactic.

Cheers