SpO2 drop and panic attack upon waking related?

[MyronH]

My normal daytime SpO2 is 94-95% max, and was the same at night until recently. I've been noticing I now drop to 90-92% sometimes for periods of time (30min). This morning I woke up with a very warm feeling in my face. SpO2 was 91% on both my Contec CMS50F and a finger oximeter. My HR also shot up over 100bpm. This has all happened several times recently. Two weeks ago, I was waking up, and just moved my legs, and for no apparent reason, had a major panic attack. This has been going on for a long time for me and now I suspect it has something to do with low SpO2 or poor blood circulation at night. I've had two DVT's/PE's and one AFIB incident in the past and take Xarelto. I also have a little scarring along base of one of my lungs, possibly due to some infection or cold I had in my lifetime. 

I have (2) CMS50F's and tried each one out every other night, and they show same SpO2 drops to 90-92%, when I wake up during the middle of the night or in morning. 

My AHI is well controlled, but not sure why my SpO2 would drop to 90-92% and why I have major panic attacks upon just waking and moving around in bed. My Pulmonologist did a walk test up/down stairs, and my SpO2 dropped 92%. I've tested this myself at work, and it goes down to 90% with HR 130+. I know I'm out-of-shape, but at 47yo, I don't think it's normal.

I'm having an Echocardiogram Stress test in a few weeks, but I suspect it won't show anything. I just had one two years ago, and I've had previous heart tests which was all normal. They said if that comes back negative, they may order a VQ Scan of my lungs, to check for remaining clots and blood flow. My hematologist did recent blood work with D-Dimer test, and it was negative for clots.

Previously I posted about my recent airline flights where I was getting dizzy and my oximeter showed 85-90% during the flights. My doctors had no answers for that and said to wait for my stress test.

Anyone know why SpO2 would drop down to 90-92% at night, with no apnea?

[ardenum]

I'm 30 and i get to 130's from walking the stairs too, im not even overweight. In my case it's ME/CFS.

One possible thing would be low hemoglobin, another since your heart is running 130 bpm it might not be pumping blood effectively.

Xarelto is a controversial medication, studies have shown that a poorly controlled warfarin therapy is more successful and with less dangerous side effects then a pill-a-day xarelto. If i had to get on a blood thinner I'd avoid xarelto and its peers like pradaxa. But if you're already on it I dont know what to really suggest besides going to some renowned heamatologist.