On Thursday, October 3, 2019 at 4:45:05 AM UTC-4, John McLaughlin wrote:
I've searched this forum and google, but can't find the information - can
anyone tell me what readings I should expect to see at altitude?
Presumably, a steady decrease from the ground level reading, despite using

supplemental oxygen? But without a table of what's normal for each
altitude, how can you know when you need to be descending?

I was able to maintain 96 - 98% to 31,000 on my system (constant flow, with a good re-breather mask).

If you can't maintain 92% or higher, then something isn't right and needs to be corrected. Most people function at/near normal mental acuity at 92%.

When things aren't right, I've seen ox saturation go into low 80s. In the low 80s you will be seriously impaired and you need to correct your problem right away.

Chapter 1 for basic high altitude oxygen physiology
http://www.operationalmedicine.org/T...eonsManual.pdf

Side note: the armed services use way better equipment and procedures than we do, and the typical military aviator is young, and healthy and getting closely examined with regularity and deep suspicion. They don't use nasal cannulas for anything and they don't try to economize.

I agree with Jean Marie Clement (Dancing with the Wind): the regs are anti-conservative.

At 14,000 without ox, you will probably find that your saturation is really bad.

T8