0xdec0ded [Therapy Thread]

[0xdec0ded]

Sleep Study: 01/05/2022
Untreated AHI: 20.5

   

   

Diagnosed: 01/14/2022
Impression: Moderate OSA

   

Therapy has been going very well so far (AHI < 1 and hours > 5 from the start) but my oxygen has changed very little from my pre-CPAP measurements.  I'm curious if that takes awhile to come up or if some adjustments are needed?

OSCAR charts will follow in subsequent posts.

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Machine arrived 05/07/2022

Prescription was for pressure 4-20, but I changed it to 7-20 after the first night based on various posts I read here.  I also turned on Smart Start as it has worked well for me so far.

On the third night (05/09/2022) I experimented with different nasal pillows (M -> L) and that didn't go well.  On the fourth night (05/10/2022) I tried S, also not great.  Probably sticking with the M from now on.


05/07/2022
   

05/08/2022
   

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05/09/2022
   

05/10/2022
   

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The last couple nights I seem to have learned a new trick... taking off the gear in the middle of the night.  

I'm still concerned about the number and severity of SpO2 drops I'm getting.  Does anyone have any ideas about this?  Should I be concerned about these?

05/11/2022
   

05/12/2022
   

[Crimson Nape]

The drops look like artifacts. They drop and recover too fast. You must be one restless sleeper.

[kappa]

The drops are similar to what was in the sleep study. At this scale you expect any desats to be fairly fast (i.e. drop over 10-30 seconds, recover in slightly longer time). Your SpO2 numbers seem quite low in general - median of 90% - are there any other medical conditions involved here?

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Just a high BMI (~47) and pretty serious metabolic issues which make weight loss extremely difficult.  These are undoubtedly related to the apnea and low O2.  My blood pressure, A1C, lipids, etc. are all normal, not even pre-diabetic.  Given the extra threat that COVID poses to someone like me I've been extremely cautious throughout the pandemic and have never been sick so I believe I've avoided infection so far.  I bought an oximeter as a COVID precaution and it beeping at me all night during a test is what eventually led to my sleep apnea diagnosis.

I'm currently on a ketogenic diet but I've tried all kinds of different diets like most people in my position have.  I eat a lot of vegetables and little to no processed food.  Exercise has always been a struggle and I never knew why but maybe my O2 coupled with my weight helps explain that.  Despite all this I've lost ~35 lbs in the last 9 months or so.  Slow going, but going in the right direction.

I always assumed there would be a strong inverse correlation between AHI and SpO2 and once I got my APAP that I would see a marked increase in my SpO2, but instead it seems to have just made my SpO2 more consistent.  The median is about the same before and after APAP, but there are far fewer highs and lows.  Maybe this is expected and I just misunderstood the role that an obstruction plays in what happens to SpO2?

For comparison, here's an oximetry-only baseline from before I got my APAP:
   

[kappa]

There's a strong correlation between AHI and ODI, which is what you're seeing with SpO2 being more consistent. I read that there's some correlation between high BMI and lower resting SpO2, potentially due to increased oxygen consumption and reduced lung volume. CPAP aims to splint open airways to prevent obstruction which doesn't necessarily address SpO2 levels outside obstructive events.

EPR/Pressure Support may increase Tidal Volume but your respiratory drive may reduce Respiration Rate to maintain the same Minute Ventilation - respiratory drive being driven off CO2 levels rather than O2 saturation. Just did a bit of a search and it may be worth doing some research and discuss with your doctor/s around Obesity Hypoventilation Syndrome (OHS).

What's curious is that your CPAP pressures, while given the full range to automatically increase in to, are remaining quite low. The bulk of the events seem to be in REM sleep based off the sleep study, where your AHI was ~60 during REM but only 13 otherwise. The pattern from the OSCAR traces seems similar, and we see what appears to be REM related increases in heart rate variation, O2 desaturation and breathing variation but almost no apnea/hypopnea events. Perhaps an increase in minimum pressure might make a difference? (To desaturation, but probably not to baseline SpO2).

[0xdec0ded]

Thanks for that link about OHS, that definitely seems like something to look into.  I've got an appointment next week where I will bring it up.