My mother 87, atrial septal defect (just diagnosed this year), CHF, and on oxygen 24/7 at a level 3, in an assisted living memory care floor. Visited her after lunch, walked her to her room with her O2 tank then hooked her up to the concentrator which has a container of water that the air bubbles through. Mom was going to lay down to take a nap. Five minutes later I could see her shoulders heaving up and down like she couldn't breathe. I asked her if she was getting air and she said yes. Went to get an oximeter from the nurse to check her level and it was 85%. She kept breathing hard and the level kept dropping. The nurses came in to check on her and increased the level to a 5. Her O2 level continued to drop into the 70's, so I told them to call hospice which they did (she's been under care for 2 weeks now). I called my husband over and my sister as I thought this was it. Her levels were hovering in the low 70s and reached a 69 at one point. Mom started to get angry at me for dumping her in there and really didn't make much sense. She also said her stomach hurt. The head nurse kept coming in to check on her and asked if I wanted to give her some morphine to help her breathe. I told her to wait until my sister got there and hospice. So she was like this for about 3 hours until my sister got there and she went to adjust mom's nose canula and said - there's no air coming out! Husband looked at the concentrator and the bubbles were still going through the water but nothing at the other end. There was an extra hose so he put it on the machine and low and behold her O2 levels came up to 92% in a matter of minutes (or so it seemed)! Hospice showed up and checked mom's lungs and no rattling and all was good. Looks like there was something wrong with the machine so they are going to bring a new one. The nurses checked on mom more frequently last night. Very scary situation and wondered what would have happened if my sister hadn't checked the nosepiece. After this was all done we walked to dinner and she was fine and ate all of her food. I just wondered if those hours of hypoxia did any damage?