There is, however, almost no clinical trial evidence to support its use in companion animal species. Justification of veterinary use of HBOT comes only from
extrapolation from basic principles, pre-clinical research, anecdote, and extrapolation from research in humans, so this should be viewed as an unproven, experimental veterinary therapy."
You can read their full analysis here: http://skeptvet.com/Blog/2013/05/hyperbaric-oxygen-therapy-for-pets-whats-the-evidence
Hope this info helps.