B737-900
Flight Attendant Current
Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
General None Reported / Taken
Human Factors
Passenger X; boarded with a backpack in ZZZ and inflight FA B; noticed he was on oxygen and there was no note of this in our special notes on our manuals. We asked him if he'd had it approved or made CSA aware of it and he said no. It was a [model name] and FA B and I talked with his travel companion; Name and explained that when they get to ZZZ1 they need to see an agent and get approval for the unit to be able to use it on their flight ZZZ1-ZZZ2. We did not switch him over to a Portable Oxygen Bottle (POB) because we were not sure of what flow he needed and did not want to interrupt his oxygen supply that was working for him. They both confirmed they will see an agent in ZZZ1 upon deplaning. No way to have been aware of this until we saw him using it mid flight. None of us could find a list of approved units anywhere on our manuals.Not sure...the backpack was just a normal generic backpack and was stowed for takeoff so until mid flight when we saw him using it we had no knowledge of it. We all tried to search 'approved O2 Concentrator' to see if it was approved but could not find a list on our manuals.
B737-900 Flight Attendant reported a passenger using a breathing device during cruise without prior airline approval.