Ears shallow

[nigelH]

Often after a dive I find I am getting the feeling in my ears of an ascent.
I mimic a yawn and it clears. I've usually put that down to residual off gassing into the internal ear works and thought nothing of it.

However I have it tonight. I was diving the YBOD to see that I had reassembled it correctly after getting Brent's snazzy detachable counterlungs mod done so I was on 0.7 bar ppO2 in a 3m pool.
That's 70% O2 on the surface and 54% with my nose on the tiles at the deepest point. A max EAD of minus 2.6m!
I was in the water for about an hour but most of that was mooching about watching the temp-stick wondering if I has really only used half the scrubber in four hours so it wasn't all on the bottom.

OK it was actually 18/40 trimix so at the bottom of the pool I was on about 0.3bar each of He and N2, on the surface 0.15bar of each and for quite a lot of the time it was 100% O2 so none of either.

I find it hard to believe I gassed on enough gas to notice.
Is the 0.3 bar of helium to blame?
Is my usual aprés dive theory wrong and it's not off gassing?
Have I missed something obvious?

[gibbon]

Nigel,

I fear you are missing something obvious - you have put an O2 rich mix in your ears and your body does absorb the O2 leaving your ears under pressured... can be dangerous if you go to sleep with 100% O2 in your ears!

You need to flush your ears

Jon

[Janos]

I get something similar if I've been breathing a rich O2 mix on descent (which happens a bit at the moment as I'm doing plenty of skills and drills). I put it down to the O2 in the middle ear being metabolised. I remember reading about this in a Proper Book (It may have been Mastering Rebreathers). So it must be true.

Janos

[Freeflow]

There is a theory doing the rounds at the moment about O2 causing bends in the inner or middle ear. I don't know too much about it, I saw a reference in a PSAI manual I was flicking through. Might be worth asking on the 'medical' forum?

[recurve]

Originally Posted by jonny

Nigel,

I fear you are missing something obvious - you have put an O2 rich mix in your ears and your body does absorb the O2 leaving your ears under pressured... can be dangerous if you go to sleep with 100% O2 in your ears!

You need to flush your ears

Jon

But if your ears are 'under' pressured i.e. at lower than ambient pressure, then it would be the effect found when descending, rather than the feeling described by the OP which was that it felt like 'ascending'.

Wouldn't it?

[gibbon]

Originally Posted by recurve

But if your ears are 'under' pressured i.e. at lower than ambient pressure, then it would be the effect found when descending, rather than the feeling described by the OP which was that it felt like 'ascending'.

Wouldn't it?

um.. a re-read makes me agree with you NigelH is obviously a strange bloke or perhaps the sensations are hard to tell apart back to Nigel on that...