CPAP and BIPAP troubles

I'm new to the forum so I hope I do this correctly. About 6 months ago I got checked for sleep apnea and, due to a health issue at that time, I had to sleep on my back. The home sleep test came back that I had sleep apnea and the doctor ordered CPAP which I started to use. After that I had a surgery and after the surgery (when in the hospital) since they were monitoring my oxygen levels we realized that the CPAP was not effective as my levels would drop and the alarm would go off. In the hospital they temporarily gave me an Auto SV Bipap which worked great. However, I then went back to the sleep doctor who ordered another sleep test and then gave me a regular BIPAP which it appears may have caused some central apneas. I didn't feel good on the BIPAP and now am scheduled for another sleep study. Since I am now able to sleep on my side I have been doing so (without a CPAP or BIPAP) and bought my own recording pulse oximeter to see what my oxygen levels were now during the night. This was a different story. My oxygen levels remain about at 92% to 95% while sleeping and there are maybe a couple dips to 90 or 88 but these last only 10 seconds or so. This is a lot better than the oxygen levels that I had while on the BIPAP. I told this to Physicians Assistant during my last appointment but she insisted that sleep apnea and oxygen levels were two different things. This doesn't make sense to me. If the oxygen levels are good then why would I need to have a machine help me breathe? Any thoughts from anyone here would be appreciated. I am considering going to another doctor for a second opinion but would appreciated any thoughts here. Thanks!

The size of the drop in your oxygen is only a part of the story, and not the most important part. Even with only a small dip in oxygen saturation, if there is an EEG arousal (i.e. interference with what your brain is trying to do in sleep) it can still be damaging to both your quality of life and your health.

It is possible that you have positional OSA that is much worse on your back. The fact that you slept so we'll with the Auto SV BiPAP may or may not be significant. The Auto SV can be set in a number of modes and I assume that you don't know how it was set when it worked for you.

With such limited info I really have no idea exactly what is happening in your case. If I were you I would keep working with your health professionals but make sure that you drill them for information as much as you can. Make sure that they explain to you what they are doing and why. It can be very complicated to nail down the exact cause of sleep related respiratory disturbance in some cases (trust me) but there is a structured way to approach it. If there is a range of different people working on your case it can be easy for the process to get confused as each person only has part of the story. You need to be the one who keeps everything working logically and together in a sensible direction, because you can't always rely on others to do it for you (even if that's their job).

In short, educate yourself a bit and make sure everyone explains what they are doing at every step. Ask questions. Good doctors will be happy to answer them and involve you in the process.

Thank you very much for your reply. You explained the concept of the EEG arousals really well. That finally makes sense to me. Now I understand why my doctor's office still thought it was important to go forward. Thanks for getting me off the fence about this. I'll keep going forward on the plan and get more involved and informed.