stupid question about pulse oximeter reading...

[lvehko]

OK, I found a reasonably-priced pulse oximiter (on Amazon, where else?) -- the only problem is, how do I read my sats when I'm asleep?!? I asked my husband to read it when I was taking a nap with my CPAP on, and he says it was at 98%. However, I'd like to get some readings during my deepest sleep, which, naturally, is in the middle of the night when he's asleep also. I guess they must make Oximeters that collect data over time, in which case I guess I just spent $70 to know that I'm fully saturated when I'm awake (which seems kind of like a no-brainer to me)...

A related question -- when a person gets 'desaturated,' don't they go right back up to +90% as soon as they take a full breath? I guess this is goofy stuff, but I tried holding my breath with the thing on, and it never went below 97%.

Min

[CUatX]

Maybe what Wikipedia has to say about pulse oximeters will answer your question.

[NightHawkeye]

I guess they must make Oximeters that collect data over time ...

Yes. Called Recording Oximeters they sell for considerably more. Most require external software which is an additional expense. The Nellcor N-395 which I use happens to have a large front panel display which allows one to view overnight data without computer software (although the N-395 is compatible with software, too). I haven't priced any recently, but I believe recording oximeters are all still in the over $300 price category, even in the used equipment market.

A related question -- when a person gets 'desaturated,' don't they go right back up to +90% as soon as they take a full breath? I guess this is goofy stuff, but I tried holding my breath with the thing on, and it never went below 97%.

Yes. I've observed the same thing if I take oximeter readings while awake. While asleep I sometimes see a long, slow decline which correlates with long apneas. At other times, however, I have seen very quick declines. It is those quick declines (frequently showing up in sleep lab data) which cause concern whenever they drop to low saturation levels. The only thing I've read which begins to address the phenomenon is a correlation in OSA patients showing that many/most OSA patients also have PFOs. A PFO (Patent Foramen Ovale) is a hole between the atrial chambers in the heart allowing desaturated veinous blood to get mixed with oxygen-rich blood, thereby desaturating it. Approximately 25% of the population have PFOs. The condition is generally considered benign by the medical community. (The same medical community which often ignores OSA.)

Probably more than you wanted to know, huh?

Regards,
Bill

[dllfo]

THANK YOU BILL -- for mentioning the PFO thing. My oxygen numbers were 90 or better at all the doctor's offices. So I bought my SPO 5500 and started logging my readings. I was in the low 80s at home. AND my sleep study said I went into the 70s.

Still, I was like you, I knew something was wrong but the Medical Community (think Insurance here) were not convinced until I kept my "diary" for a couple of weeks. Then my Pulmonologist had proof of my problem.

They finally got me to go to the National Jewish Hospital in Denver, CO for a week of testing -- I got home 6 weeks later. I had the PFO. If you seriously feel like you don't have any energy, you yawn all day, fall asleep at your desk or in your chair at home....ask for a test called "Echocardiagram with agitated saline". Easy test, minimal pain. That is how they find a PFO.

My oxygen levels are back in the low 80s again, we aren't sure why. Denver again I guess.

"When people get "desat", don't they go right back up?" Not all people. I did not. They ran my pulse ox down to 18% in the hospital and I did not know it. Only when they gave me oxygen, instead of carbon dioxide, did my oxygen levels go up.

Luckily, being Irish prevented brain damage at such low levels of oxygen

A good Pulmonologist can check you out. Good Luck with it.

[lvehko]

While asleep I sometimes see a long, slow decline which correlates with long apneas. At other times, however, I have seen very quick declines. It is those quick declines (frequently showing up in sleep lab data) which cause concern whenever they drop to low saturation levels. The only thing I've read which begins to address the phenomenon is a correlation in OSA patients showing that many/most OSA patients also have PFOs. A PFO (Patent Foramen Ovale) is a hole between the atrial chambers in the heart allowing desaturated veinous blood to get mixed with oxygen-rich blood, thereby desaturating it. Approximately 25% of the population have PFOs. The condition is generally considered benign by the medical community. (The same medical community which often ignores OSA.)

Probably more than you wanted to know, huh?

Regards,
Bill

Yikes. Very interesting, and also scary. Here's the Wikipedia link, for those interested:

http://en.wikipedia.org/wiki/Patent_foramen_ovale

Min