Auroraborealis Sleep Data thread - thoughts on hypoxemia

[Auroraborealis]

Before I dive in, I want to say that this community and this site are so impressive. I've been lurking here and there for several months and have already learned so much...so, thank you.

I've got a host of complex chronic illnesses, and while my hunch is that most of them are related in some way, I haven't suspected my sleep disorders to be playing a huge role in the overall scheme of things. Mostly because my sleep apnea is not severe, and my narcolepsy has been a constant throughout my life and isn't typically associated with the other issues I'm having. However, the CPAP + oximetry data I'm able to collect and analyze, thanks to OSCAR, might be helpful in getting to the teasing out some of what's going on. And if I can improve my sleep quality along the way, even better!

I've had random SpO2 desaturation events--some alarmingly low (frequently in low 80s)--for at least a few years. Sometimes they correspond to the onset of other symptoms, like headaches or fatigue. Other times, they're essentially "silent," and I don't know they happened until I happen to look at the data on my AppleWatch.  But I feel bad almost all the time, and some days I'm essentially bed-bound--so it seems reasonable to me that hypoxemia is playing a big role. However, so far, I have had terrible luck with healthcare providers, and no one has investigated very far or offered any explanations beyond "device error." 

I'm slender and appear fit--and I have been rather fit until the last few years when my mysterious illness has set new rules for my activity level. And while I haven't typically thought of myself as "short of breath," I have always experienced irregular breathing patterns (lots of sighing; slow, deep breaths) and air hunger. 

I had a pulmonary function test in December that was mostly unremarkable except for some indications of hyperinflation. It looks like I have excellent (much better than expected) lung volume and no apparent structural reasons for frequent desaturation events. The pulmonologist was not interested in investigating further and said my desaturation events were device artifacts, even though I had an event IN HER OFFICE that was captured on both her clinic oximeter (64%!!) and my Wellue O2Ring (80%). I think she thought I was faking being dizzy and confused and having to sit down. 

Oddly, my desaturation events seem more common when I'm upright vs lying down, which is why I sometimes wear the oximeter during the day. Maybe that means the CPAP is working? Or maybe it's an important clue to what's causing the drops.

I know that's a long introduction--thank you if you read this far! 

Here are my questions: 
1. It looks like my Tidal Volumes/Minute Vents are low (median Tidal Volume right around 300-325). Is that concerning, and if so, what does it point to? It seems odd to me, given that my PFT showed my lung volume to be greater than expected. Could it be a clue to my hypoxemia?

2. I was a reluctant CPAP user, but since I have it, I want to be getting all the good from it that I can. I know that some of you get your AHIs down to teeny tiny numbers, while mine seems stuck at 4-6. My sleep specialist is satisfied and says I'm likely one of the few that just doesn't see a remarkable change with CPAP. Is that true, or are there settings to be tweaked that can help me get more out of it?

Thanks so much for sharing your thoughts and expertise.
       

[Auroraborealis]

I just thought of something that is relevant to share. I have neck problems, severe spinal stenosis, and atlantoaxial (C1-C2) instability. My neurosurgeon has suggested intermittent compression of phrenic nerve (controls the diaphragm), which might explain irregular breathing patterns (and possibly central sleep apnea?) but I may be misinterpreting what he said. I have a follow up Friday so I'll ask for clarification.

[cdplatt]

Any diagnosis of bradycardia (slow pulse) and/or low blood pressure?

[Auroraborealis]

Yes, bradycardia as well (resting heart rate 40s/ low 50s, sometimes drops into upper 30s during sleep), but no one seems interested in that. 

Apparently I look well enough to providers that they just dismiss abnormal findings.

---

And blood pressure varies, sometimes wildly. I always had low blood pressure until I was about 40, and then it flipped to mild hypertension. But currently I would say it is rarely low.

[Auroraborealis]

Also realized I should have included the other OSCAR graphs.
     

[quiescence at last]

the machine is responding to a restriction in the flow path for breathing in and possibly out. The flow limitations chart looks pretty good. you'll have to attack the leakage as well. the fact that you are experiencing obstructive apnea and hypopneas indicates there is not a high enough pressure to keep the flow path open.

If it were mine, I would want to have a minimum of at least 7, because the charts show the OA as happening for the most part when the pressure is below 7. I would cap the maximum pressure at this point to about 11.0 because the charts show the pressure doesn't generally exceed that anyway, and higher pressures can sometimes cause awakening, thus disturbances.

I would also look at the potential of positional affects causing some of the restrictions. During certain portions of the charts, the machine wants to boost and keep higher pressures to ward off restrictions. Positional apnea is generally caused by relaxing to the point that your neck bends enough to squeeze off flow. I don't think there is much the machine can do if you kink the air hose (throat).

Good luck.

QAL

[Auroraborealis]

Really appreciate the advice, QAL.
Would it be okay to change those settings tonight--min 7, max 11? Or do I need to adjust it more slowly?

[quiescence at last]

Sorry, I missed that. This step can usually be done all at once.

QAL

[Auroraborealis]

Ok, thanks! I was a little uncertain, so I changed it to min 6/max 12. I slept fine, but I haven't looked at the data yet. 

I'll go ahead and increase the minimum to 7 and give that a try for a while to see if things improve.

One more question: is there any reason that change would be contraindicated in someone with indications of hyperinflation on a pulmonary function test? Any risk of pneumothorax, for instance? I recognize this site isn't for medical advice, just looking for an educated opinion.

[quiescence at last]

when I want to read something about a certain condition, I do internet search for the terms and add "NIH" to the search terms. so, naturally, I looked for "indications of hyperinflation NIH study". it led me to a site that discusses counterindications.

I noticed in your charts that both minute ventilation and tidal volume were definitely on the low side. It does look like the respiration is good, though.

If you have hyperinflation or issues with pneumothorax you should have directions from your doctor. If your doctor prescribed APAP with min of 6 max of 11 and an EPR of 3, I would be wary to increase max pressure or reduce EPR from 3, and just ask the doc about these subjects. However, if you got a prescription for APAP at 6 min 20 max they likely already cleared you with respect to those potential situations.

Good luck,

QAL