WZ,
Your insurance person is correct about using 99183 to identify/charge the hyperbaric oxygen therapy session. 99183 is specifically defined as physician attendance and supervision of hperbaric oxygen therapy, per session. Be careful though because other codes can be added to this that can change the reimbursement for your visit. For example, if you had an examination or other procedure in the hyperbaric oxygen treatment facility in conjunction with a therapy session other codes would be reported for those procedures, etc. If you really want to get to the bottom of this I would call your physician's office and ask them for copies of the claims submitted to your insurance company and pair them up with the explanation of benefits (EOB) you got back from your insurance company (by date of service). Compare the codes by visit and between the claima nd the EOB and note descrepancies. I would be happy to review those with you and help you determine who to talk to at the insurance company and what to tell them you need/want.
Amy