The pressure was less than two atmospheres, so, not too hard on the ears when pressuring up.
In reply to @ericvnelson. If you were in the chamber for 1-2 hours/day that may not have been enough. I went for 80 hours (out of a recommended 98) before I took a break for a vacation. The hyperbaric oxygen therapy (HBOT) had a beneficial effect for me but my neuropathy does not sound as severe as yours. Mine started in my feet and was up to my waist when I started HBOT. At the end of the 80 hours (every day from Dec 13 to Jan 25 with some 5 hour sessions) my legs were stronger and the pain was restricted to my lower legs. After my vacation, it has come back and is back up to my waist, so I may go back and take some more sessions. It may not be a cure, but it does seem to help.