Unable to breathe with nitrox enriched air

[Ben Prusinski]

Folks,

I had an embarassing event happen to me while diving from a boat this weekend. Using enriched air nitrox 36%, at depth 22ft, I was unable to breathe through my regulator even though both the regulator and tank had plenty of air. I did an emergency ascent as I learned in Open Water training and surfaced back to the boat. I was out of breathe and had trouble breathing. Fortunately, I am ok. Any ideas why this would happen while using a nitrox tank? It was my first time diving with nitrox and I had completed the PADI nitrox diver training course. I checked the tank and regulator and both were functional.

 

[SeaCobra]

not a lot to go on here, but I would check a couple of things - was the tank valve fully open? and double check the gas? any chance to do a CO test on it?

 

[Jim Lapenta]

This is not a nitrox issue. That you think it may be doesn't say much for your nitrox class. Or training over all.

Nitrox will not affect how you breathe or if you can breathe.

This is not a Nitrox issue but a gear issue. Was the valve all the way open?
Where did the tank come from?
When was the last visual?
Did you report it to the shop?
There may have been something in the tank that needs attention.
Did the reg stop delivering air altogether or just become very hard to breathe?
Is it your reg or a rental?
How did you check the tank and regulator?
If the valve is not all the way open the tank will breathe fine on the surface but not deliver air at depth.

Another item that should have been covered in your training. This should have been in your OW class training.

In order to offer a more concise opinion we need more info. And why was it necessary to do an emergency ascent? Where was your buddy? OOA, tank dry or not delivering air, is not a life threatening event if you are using good buddy procedures.

 

[racerx_]

It seems unlikely this is a nitrox issue.

Did you try your octo when u couldn't breathe through the primary regulator? I'm assuming you tested em all before and after u got in the water..

Sent from my HTC Incredible S using Tapatalk

 

[Jim Lapenta]

Going to also add after reading the post again did you have some type of anxiety event? Panic attack? What was the water temp? Conditions? lots of variables.

 

[Mr Carcharodon]

Well something is blocking the gas from moving. Possibilities are a blocked dip tube in the tank, or a dirty filter at your first stage inlet or a partially open tank valve. Take a look at the inlet filter on your first stage and make sure it looks clean. Moving the reg to a different tank can check if it is a tank valve issue. Also do make it a habit of reaching back and touching your valve at the start of dives. You really should be able to turn your valve on by yourself and have enough muscle memory to do so without thinking it through. If you can't now you may have to move your tank up a bit. What did you do the check the functionality of your reg and tank?

 

[Quero]

Sounds like the valve wasn't open all the way. When the valve is not open far enough, you can breathe okay from the regulator on the surface, but when you get down to depth, it doesn't deliver air properly.

 

[Peter Guy]

Some clues from the OP's post certainly suggest that this was a case of "Opening the valve all the way and turning it back 1/4 turn" when the valved had already been opened -- that is, someone closed the valve and then opened it 1/4 turn.

To me the telling point was that "I checked the tank and regulator and both were functional" which argues against something like a clogged dip tube or other malfunction.

OP -- when you did your gear check prior to entering the water, did you watch your SPG while you breathed your regs?

[edit -- Quero -- great minds think alike.]

 

[ntmainstrm]

Did you happen to try your alt before the CESA?

 

[MXGratefulDiver]

For future reference ... nitrox and air breathe exactly alike. You can't physically tell the difference while breathing them. The only difference is what the reduced nitrogen level does inside your body while diving ... or what the extra oxygen level can do to it if you go too deep.

As others have indicated, the most likely cause was that your tank valve was only partly opened, restricting the air flow. This isn't uncommon, and the classic symptom is that you'll be able to breathe off the reg just fine on the surface, and it will get increasingly difficult as you go deeper. If it should happen again, look at your gauge while trying to inhale. If it visibly moves, you need to turn the tank valve to increase the flow ...

... Bob (Grateful Diver)