Pulse oximeter?

[Vince R]

It’s been suggested to me that age, health and other factors influence your altitude tolerance. Okay, I agree - so I picked up a small pulse oximeter I can use in the cockpit to check my oxygen levels during long flights at higher altitudes.

My question is how to interpret the values. If I read 98 or 99 on the ground, when is it time to put on the mask? 90? 60? 30?

 

[RyanB]

The values that the device reads are the blood oxygen saturation levels given as a percentage. If the BOS levels fall below 90, which is a typical benchmark, than supplementary oxygen should be used at that point.

I’m surprised that your device didn’t include a pamphlet on this information.

 

[wilkersk]

If you’re a long time smoker or have impaired lungs for other reasons, it’s not uncommon to see sats In the low 90s even at sea level. But if you’re healthy, and see your sats falling below mid 90s inflight, a little extra O2 will have benefits. Might save you a headache, or keep you from feeling so wrung out when you get to your destination.


https://www.flyingmag.com/how-it-works-pulse-oximeter

 

[SbestCFII]

You %Sats adjust quickly to changing concentrations of inspired oxygen, or in the case of altitude, changes in the partial pressures of oxygen. Spot check yourself for a few minutes for every altitude above 5000 just to make sure you're good. Above 5000, you probably won't feel any effects until you hit 10,000, when your night vision acuity may be affected. If you have lung disease, if may come as low as 8000. In medicine, you consider %Sats above 93% (94-99%) to be normal. Below 94% the arterial oxygen concentration (pO2) drops much more sharply. Normal is 80-100, but When you %Sats are 90, then your Oxygen concentration is 70mm, lower in colder temps, and this level can produce serious symptoms. To be safe, if you're pushing 93-94%, you really need to be on oxygen, or pick a lower cruise altitude.