I'm not a medical type but I'm an avid techincal scuba diver. I have come across portable hyperbaric chambers. If I have time I'll try to do a search an see if I can find a picture of one. If my memory serves me correct these chambers can be used for high altitude sickness. I've done a little mountaineering (nothing major and only a few times) and it would seem to me that a portable chamber would be at best marginally effective for someone with mild symptoms.

Also for diving related injuries pure O2 is really the only way you can help your body tissues to recover. So this type of chamber imo is almost useless.

Found a link