Lower altitidue & improved Sp02 readings

[MCS2014]

For the holidays I stayed at a location closer to sea level and noticed Sp02 levels greatly improved that I attribute to atmospheric changes:
 
~640' elevation and 61% humidity resulted in higher Sp02 levels (96% avg) throughout sleep + 0 seconds of <90% time
vs.
my home at ~3000' elevation and 29% humidity gives me lower Sp02 (93-94% avg) + 1-15 minutes + of <90% time.

Although a 3000' elevation is not high, I've observed this on more than one separate occasion. I would conclude that the higher elevation and perhaps lower humidity is contributing to mild-moderate hypoxia. I also observe having better digestion and am less stressed when waking.

Has anyone else noticed a similar phenomena?
 
The issue with humidity can be resolved with increased the humidity in the CPAP + using a external humidifier, but have no idea how to resolve the altitude issue. I have recently been prescribed supplemental 02 and for the first time, am getting 0 seconds of <90% time consistently and my 02 scores have improved as well. AHI readings have stayed pretty much the same but the Clear Airways readings have been @ zero.
 
It seems unfortunate to have to resort to adding a 02 concentrator because of living at a higher altitude.  
 
Study here and here.
 
Has anyone else noticed a similar phenomena? Thoughts?

[desaturator]

My understand is that a "normal" SpO2 of ~98% at sea level will typically fall to ~95% at 3000ft. That's after acclimatization. Before acclimatization, the difference could be more. However, people who live all the time at higher altitudes typically experience blood chemistry and blood count changes that results in oxygen content of the blood is not as reduced as might be expected from the SpO2.

It seems to me that most of what we know about SpO2, we know from measurements near sea level. It may not be helpful to rely on it as much at altitude. Unfortunately, tracking your sleep-disordered breathing by sequential arterial blood gas measurements would probably not be well-tolerated.

BW, DS

[SarcasticDave94]

What's the relevant Apnea events regarding the elevation differences? I wonder if CA differences will be noted.

[Ratchick]

As Desaturator said, it's normal to have a lower SpO2 reading at higher altitudes and it doesn't take much to make a difference (especially if you have other issues that might interfere).

"Unfortunately, tracking your sleep-disordered breathing by sequential arterial blood gas measurements would probably not be well-tolerated."

Haha! Nope. My stepdad has severe COPD, last time he was in hospital, they left an arterial line in his wrist to do repeated ABGs and he was not happy about it.

When I was in the hospital a couple of months ago, they DID decide to perform EACBGs (earlobe arterialised capillary blood gas) on us at 5 am (every day) when we were all still asleep. I wouldn't have minded so much but they blob Deep Heat onto your earlobe to do it. That stuff REALLY freaking hurts when it runs down your face and into your eyes. 0/10, would not recommend.

[staceyburke]

I live at 4600 ft. Yes my O2 level needs O2 every night. I went to Las Vegas at 2000 ft and did not need O2 for the 6 days I was there. I don’t know if I had stayed there longer if I would have needed supplement O2.