Thanks for asking and I’ll share my experience. My recording oximeter is no longer made and was not certified for medical use. But it worked well. Currently both Amazon and eBay have many “overnight sleep recording oximeters” for sale. The tech has greatly improved and are typically priced from $89 to $199 for the good ones. Insurance can pay for these if prescribed by your doctor. Some advertise you can pay for it from your medical saving account. Just enter the quoted name I typed above and both sites will bring up a huge display of good recording oximeters for sale.
Now as to a cpap machine, my pulmonologist prescribed one for me 10 years ago. It does help a whole lot as I used to have “events”, low oxy, 4-5 times per hour. (I have central sleep apnea not obstructive sleep apnea, which may be your situation.) With the machine, I still have a few events per hour but only 1-2 minor events that don’t wake me. But typically after 5 hours, I awake with an adrenaline pumping heart pounding event like I’m exercising. Then I have to get up and go to the bathroom as the kidneys really go to work with the adrenaline. Deep breathing for several minutes as I go back to sleep seems to help a lot and I do sleep deep for another 2-3 hours. If you are finally prescribed a cpap machine, the truly best ones are the ResMed series. I have a ResMed 11, and it’s been the absolute best of the 4 I’ve had. Do not, Do not purchase any Philips cpap machines as their recalls and legal situations have been significant. I hope my notes here will help you. Pressing your doctor with all the events that happen to you is critical to getting your doctor to take action! The overnight sleep recording oximeter should provide legitimate proof of low oxy levels. Best of luck and do press on!! ///