[CPAP] 1.5 years of CPAP, feeling like I've been run over by a garbage truck lately

[MyNoseDoesntWork]

I am an in-shape male in my late 20's, former powerlifter. Believe that my SA was brought on due to my neck measuring around 18.5in at peak, however my sleep has been awful my entire life - I'd have periods of insomnia and periods where I'd sleep for 15-30 hours at a time. Never really woke up feeling "rested". Blood tests/physical exam/etc all normal. Diagnosed January 2021, in home sleep study showed 8.3AHI and lowest O2 86%. Lost a lot of muscle since then, sitting around 205lb down from 225lb. Can't say sleep quality improved any from the weight loss though.

Recently I've been feeling even more tired than usual. Monitoring 02 with an EMAY pulseox. Noticed that I drop down to 92-93% pretty often, which will spike my HR up 10-20bpm. Average O2 will also slowly drift down during the night and leave me hovering around 94% with drops to 89-93%. Average overall O2 has been 94-95% for the past 3 nights.

I am using a resmed autoset 10 with N30i cushions. Pressure set 8-18, EPR -3 since June, which appeared to have lowered my average AHI and apnea time slightly. Including a example from this week that had a much higher event count than usual but is only 3 hours, and the longest night of use I've recorded in this past month - I have a bad tendency to wake up 2-3 hours before my alarm and I often go to sleep without it. Also including a screenshot of my O2 data. It says that I am desatting by >3% 14 times/hour.

Regarding my sleep schedule - I'm a nurse & work nights often, so it's not great. Recently quit and am trying to get it back on track.

If anyone has any ideas before I end up dropping dead from sleep deprivation, I'd love to hear them!

[Brazen]

I'm a nurse as well and working nights ruins sleep quality. You said you quit? Get yourself on a normal sleep schedule. That alone will make a world of difference. 

Are those O2 drops happening even when using the cpap?
If so, hopefully one of the experts here weighs in and can recommend setting changes to improve your treatment.

[MyNoseDoesntWork]

Yup, and the shift diff doesn’t make up for the fact that you lose an extra day trying to revert to a normal schedule. As for the O2, yes, the drops were with the CPAP. It won’t go much lower iirc but I haven’t checked it in a while. The machine is like white noise to me - I can’t fall asleep without the sound of it.

[Brazen]

Shift diff doesn't make up for completely disrupting circadian rhythm. It's asking your body to function opposite of all programming. 
Think about biology... is it realistic to push the body into long-term change from natural function and not experience a poor outcome?
Also consider effects of stress.
Sleep apnea is not the only cause for fatigue and unrestorative sleep. When physical causes are ruled out... what's left?
Sleep hygiene, stress management, nutrition, movement, etc.

[DaveL]

Brazen every time you post I learn something new. Thank you!

[Brazen]

Hi Dave! What'd you learn today?

Happy to help. Hope OP found something helpful too.

[MyNoseDoesntWork]

@Brazen - have we been able to rule out physical causes yet? That's why I posted my O2 and OSCAR logs. Sleep hygiene and nutrition aren't going to cause desaturations like this to my knowledge...

[Brazen]

@Mynosedoesn'twork 
I'm not an expert here so I'm hesitant to speak to your charts.
I hope one of the experts weigh in.

To me, how you feel is more important than all the data. 

Your O2 does trend down a bit but you're still spending very little time below 93%. It's not uncommon for O2 to be lower in sleep than wake.
Your O2 chart shows a total of 6.5mins under 93% SpO2, right?  Is that even significant? Is that affecting your health or sleep? Could that amount of time be explained as artifact from movement during the night? 
I don't know.

[MyNoseDoesntWork]

From my research, a mild drop in o2 while sleeping is normal, however a drop of 3-4% counts as an "ODI". From the paper I'm reading: "ODI refers to the average number of desaturation episodes occurring per hour, where desaturation episodes are defined as a decrease in the mean oxygen saturation of ≥3% (over the last 120 seconds) that lasts for at least 10 seconds."

Not quite sure what to make of it yet though. Was really hoping someone would be able to help me tweak my cpap settings to see if that brings about any improvement. The threshold for these things seems to be ~90% or so, so I'm not dropping somewhere severe.

Came across an interesting study while looking into it. Turns out, Trazodone may actually improve the quality of sleep you get as it increases the arousal threshold. Used to be the common train of thought was that you would wake up in order to re-open your airway and catch your breath, but that may actually be counterproductive. It looks like your airway re-opening may actually be a completely separate process, and that arousal was incidental. And the arousal actually prevents your body from being able to stabilize your airway while you're asleep. So keep the brain asleep, and the body figures it out on it's own!

https://journals.physiology.org/doi/full...00649.2013