Oxygen therapy - Anyone knowledgeable of this treatment? I have some questions

[Replenished]

I've found a place locally that has a hyperbaric oxygen chamber offering oxygen therapy either in the chamber or outside via a mask. I tired it out briefly before signing up and I'm concerned as to if the mask/oxygen therapy works properly, in that when breathing in the oxygen via the mask, the in breath is fine, some nice oxygen coming in, but when breathing out, to me it feels like most of my out breath/carbon dioxide is not properly going out via the outlet hole and mostly just getting stuck within the mask. It's a mask with one hole to the left attached to a tube with the oxygen coming in and one hole on the right for my out breath to go out. To get out breath to go down the outlet hole I feel I literally have to forcefully blow/push the outbreath down there.

I suppose my question is; If some of the carbon dioxide/outbreath is getting stuck in the mask and being breathed back in, is that defeating the purpose of the oxygen therapy? Is this a problem? Or would the oxygen coming in through the other hole essentially cancel out the carbon dioxide left in the mask that i'm breathing in?

The masks at this place are probably just not very effective but I just want to check if this sounds ok/safe/normal?

 

[Rufous McKinney]

Or would the oxygen coming in through the other hole essentially cancel out the carbon dioxide left in the mask that i'm breathing in?

I would be concerned.

and online I read something about all that but it was from a company that sells masks they make.

probably some science exists on this.