I arbitrarily chose a CMS50D+, the cheapest unit that OSCAR can import data from, though you have to start recording from it and the CPAP machine at the same time to time tag it.
( OSCAR says it can import data from
Contec CMS50D+, CMS50E, CMS50F, CMS50I
Pulox PO-200, PO-300, PO400
ChoiceMMed MD300W1 )
Most of the eBay ads for recording pulse/oximeters(from Contec) now carry this notice:
Most of the Amazon ads carry a similar notice.The sale of this item may be subject to regulation by the U.S. Food and Drug Administration and state and local regulatory agencies. If so, do not bid on this item unless you are an authorized purchaser. If the item is subject to FDA regulation, I will verify your status as an authorized purchaser of this item before shipping of the item.
That wasn't true several days ago. I don't know if there has been a change - e.g., if the product just got FDA approval, which might mean you need a prescription to buy the most recent units???
So I ordered mine through Walmart marketplace, which doesn't carry such a notice - perhaps they are shipping older units that didn't yet have FDA approval... It is also my hope that if it doesn't work (the reviews are mixed), Walmart will help.
Why do I want a Pulse/Oximeter? Mostly silly curiosity. But also, some sources say low oxygen events might possibly disrupt biochemistry (e.g., maybe cause or worsen Diabetes), maybe contribute to or cause Alzheimer's, and/or by forcing the heart to work harder, maybe contribute to heart disease. Your CPAP machine can detect how often you more or less stop breathing. (OSCAR may be able to give you more detailed info.) But there are more parameters that affect blood oxygen levels - e.g., how full of air your lungs are at the time - that your CPAP machine might have trouble guessing unless you buy the CPAP manufacturer's own oximeter module - which are much more expensive.
Anyway - maybe I have this all wrong, and there is no problem, and I panicked for no reason. Oh well.