Started CPAP treatment - Would like advice on my sleep study and OSCAR information

[Mythique]

Hello everyone,

I am currently renting a CPAP machine (Resmed S9), and started the treatment on december 16th. The first week I had some difficulty to adjust to the treatment, and it gradually got a bit better over time (I have less issues getting back to sleep if I woke up at night).

Before the treatment I noticed :

• Excessive fatigue during the day.
  
• Difficulty concentrating.
  
• Headaches right after waking up.
  
• Brain fog
  

Currently I see barely any improvements, I might have some days were I feel better but I am not sure it is different than before. So far this does not worry me, as I noticed that some people notice only improvements after a few months. But, my curiosity got the best of me, and I wanted to make sure that I was on the right track.

I did a sleep study at home, in July 2021, using Alice PDx. It took 6 month to get a result from the clinic, and I was having some issues that made me postpone the treatment.
My results are in french (did the study in Québec), so I am not sure my translations are accurate :

• Recording time: 508 minutes.
  
• Sleep quality during the night of recording: Sleep disturbed by the equipment
  
• Apnea-hypopnea index: 4/hr
  
• Autonomic hypopnea index [1]: 28/hr
  
• RERA Index: 0.2/hr
  
• Total respiratory event index (TREI) [2]: 32/hr
  

• TREI in supine position : 31/hr
  
• Desaturation index of 3% or more: 4/hr
  
• Average saturation: 95% Minimum saturation: 89%
  
• % time with a saturation of 90% and less: 0%.
  

[1] In french it was called "Index d’hypopnée autonomique". Here are the criteria for this index :
"Autonomic hypopnea: Decrease ⩾ 30% of baseline in respiratory signal amplitude without oxygen desaturation⩾ 3%, but associated with autonomic microarousal (pulse rate increase ⩾ 5 bpm)."
From what I read this is not commonly used outside of Québec, and I could only find information in french.

[2] I think that this is what RDI is?

And here are the comments on this sleep study :
"Possible mild sleep apnea and hypopnea syndrome. Initiation of therapy may be indicated based on clinical symptomatology."

I will add to this post a few screenshot from there "sleep study" software, I don't know if those are useful.

After this sleep study I saw a pulmonologist from the same clinic. He explained to me that I had two options : a cpap machine, or an oral appliance. His point of view is the following (again, translated from french) :

• Mr. presents a habitual snoring with apneas objectified by his entourage and nocturnal choking. He says he has a significant daytime sleepiness. The Epworth index is 9/24. He finds that his sleep is not restful. He has nocturia up to once a night. He reports excessive fatigue. He does not have insomnia at onset but has maintenance insomnia. He has morning headaches.
  
• He is in good general condition. The cardiopulmonary examination is unremarkable. He has no edema of the lower limbs. The skin and skin Appendages are normal. Mallampati of class 2.
  
• He had an ambulatory cardiorespiratory polygraphy in which the apnea and hypopnea index was 4 per hour of recording.
  
• Mild obstructive sleep apnea syndrome, without cardiovascular risk factors but with symptoms.
  
• I suggested a trial of CPAP treatment. I will see him again as needed.
  

All right, this is already a lot of information. I will add to this post two screenshot from OSCAR (please let me know if you need more information, I'll gladly post them here) :

• An overview of the last month.
  
• A recent daily page.
  

The clinic I'm currently renting the cpap machine from is not the same one were I did the study (too far from my place and did not seem to be the best).

From what I understand a sleep study at home is not entirely accurate, should I do another study in a laboratory to make sure I have obstructive sleep apnea? I notice mostly "Clear Airway" in OSCAR (but it seems that is can happen when starting a cpap treatment).

Is there anything out of the ordinary or something that I should know or change?

Thanks in advance. 

[Mythique]

Hi everyone, not much improvement, last night was kind of bad : higher AHI that the previous nights and woke up a few times.

[Gideon]

Welcome to the forum.

Thanks for the study charts. They show the signs of CO2-influenced breathing without an actual apnea. This is the waxing-waning pattern you see. It is not uncommon to see a central apnea at the nadir/low point in that pattern.
Your numbers are good and the central apnea events you see are not a concern.

That said I'd like you to lower your EPR to 2, evaluate subjectively how you feel, and compare EPR=2 with your current EPR=3 without concern for the numbers. With luck the CA numbers should go down some.

[Mythique]

Thank you for your feedback Gideon.

Nothing "wrong" with my sleep study then? If I look at the AHI I feel like I barely have sleep apnea. I think I got a bit scared by the pulmonologist saying "I suggested a trial of CPAP treatment" (I don't remember him mentioning this when I saw him, and I only received the written statement recently), I interpreted this as "the CPAP treatment my not solve my symptoms".

I mainly wanted to make sure to see if my symptoms could be caused by something else. But I guess, one thing at a time and I'll see how my symptoms progress with the CPAP.

[Gideon]

I did a sleep study at home, in July 2021, using Alice PDx. It took 6 month to get a result from the clinic, and I was having some issues that made me postpone the treatment.
My results are in french (did the study in Québec), so I am not sure my translations are accurate :

• Recording time: 508 minutes.
  
• Sleep quality during the night of recording: Sleep disturbed by the equipment
  
• Apnea-hypopnea index: 4/hr AI = 4.0
  
• Autonomic hypopnea index [1]: 28/hr HI = 28
  
• RERA Index: 0.2/hr
  
• Total respiratory event index (TREI) [2]: 32/hr  AHI = AI + HI = 32
  
•                                                                         RDI = AHI + RERA = 32.2
  

• TREI in supine position : 31/hr
  
• Desaturation index of 3% or more: 4/hr
  
• Average saturation: 95% Minimum saturation: 89%
  
• % time with a saturation of 90% and less: 0%.
  

[1] In french it was called "Index d’hypopnée autonomique". Here are the criteria for this index :
"Autonomic hypopnea: Decrease ⩾ 30% of baseline in respiratory signal amplitude without oxygen desaturation⩾ 3%, but associated with autonomic microarousal (pulse rate increase ⩾ 5 bpm)."
From what I read this is not commonly used outside of Québec, and I could only find information in french.

[2] I think that this is what RDI is?

So you have Severe Obstructive Sleep Apnea

[Mythique]

That's also what I thought at first, but the docto specifically wrote "Mild obstructive sleep apnea syndrome". I wanted to learn more about "autonomic hypopnea" and how it fits into the event calculation, and found a guide from the "Collège des médecins du Québec" (Quebec College of Physicians).

Here's a rough translation:

Cautionary note regarding level III tests (without EEG recording) and definitions of RERA, also called "high upper airway resistance", "autonomic hypopneas" or "hypopneas with cardio-acceleration"

Some laboratories in Quebec use cardiac acceleration (slowing of the heart rate when the respiratory signal decreases, with acceleration when ventilation resumes), sometimes called "autonomic microarousal," as an indirect marker of cortical microarousal on EEG. The events will then be referred to as "high upper airway resistance", "autonomic hypopneas" or "airflow limitations with cardiac acceleration". However, this approach is not used by any out-of-province panel and has had little or no reproducibility study. There is currently no evidence of a correlation between these abnormalities and OSA morbidity and mortality. Its use increases the sensitivity of the test at the expense of its specificity. The positive and negative predictive value of this test is not defined. The physician should perform polysomnography in the laboratory if the nocturnal cardiorespiratory study does not demonstrate with certainty the presence of sufficient obstructive apneas-hypopneas according to the usual criteria. Events with cardiac acceleration that do not meet the criteria for hypopneas with 3% desaturation should be reported separately from the criteria for hypopneas with desaturation.

Source in french at page 14 : first Google link when researching "site:cmq.org apnee-sommeil-et-autres-troubles-respiratoires" (I can not post links yet)

Reading this I was a bit cautious, but maybe I am worrying for nothing. My knowledge on the subject is not great, there's a high chance I could be misinterpreting things and missing something important in this quote.

[Gideon]

I'm not working with the original reports.

The numbers add up as I indicated above.  It could be your doctor ignored the hypopneas when stating severity.

[mesenteria]

There is a distinction between OSA and Hypopnea, but both are added to determine 'Apnea/Hypopnea Index', or AHI.  This figure, AHI, is what is used industry-wide and by the insurers and the medical community in concert to demarcate the various levels of disability or disorder.  It happens that a total AHI of 30 or more puts you in the 'severe' category, even if you have few or no OSA's.  I think this is what your physician means, that your OSA is minor, but your AHI puts you in the 'severe' range.  Even though you don't appear to show any actual obstructive events, the desaturations you get from the many hypopneas....EACH HOUR...remember...are enough to put a strain on your heart, raise your cortisol levels, and place you at risk of developing heart disease, diabetes through wait gain, and so on.

[Mythique]

It appears that there is a distinctiong between two kind of hypopneas in my rapport:

• Desaturating hypopnea, this one is included in the 4/hr (=AHI).
  
• Autonomic hypopnea, this is the second one (28/hr). This is the one that is causing my confusion.
  

I omited the criteria from my rapport, here they are:

• Respiratory events: Minimum duration of 10 seconds
  
• Apnea: Decrease of more than 90% of the respiratory signal
  
• Desaturating hypopnea: Decrease ⩾ 30% of the baseline value of the respiratory signal amplitude associated with oxygen desaturation ⩾ 3%
  
• Autonomic hypopnea: Decrease ⩾ 30% of baseline respiratory signal amplitude without oxygen desaturation⩾ 3% but associated with autonomic microarousal (pulse rate increase ⩾ 5 bpm).
  
• RERA: Inspiratory flow limitation suddenly normalizing in association with autonomic microarousal.
  
• The apnea-hypopnea index (AHI) does not include autonomic hypopneas.
  
• The total respiratory event index includes apneas, hypopneas and RERAs.
  

Again, thank you so much for taking the time to answer, it is greatly appreciated!

[Mythique]

The numbers add up as I indicated above.  It could be your doctor ignored the hypopneas when stating severity.

One important thing about this, my insurance will not currently cover the CPAP machine because it was diagnosed as mild. If it appears that the severity was missjudged, I think I would now be covered, which would be a huge thing.

Here are some points I'm trying to understand better :
- Is the distinction between autonomic and desaturating hypopnea often used? Is it an important one (the quote from one of my previous message seems to indicate that it is)?
- Would another sleep study done in a laboratory be helpful in some way?

I don't know if I'm reading too much into this, but I feel like there's something that is still confusing (the doctor's comments, the recommandation from the Quebec College of Physician, my lack understanding about autonomic hypopnea, etc.), and I want to make sure that my symptoms come from sleep apnea and not another thing that I might have and was not diagnosed. I am currently way too tired, and I hope my messages here are not too insistent.