OSCAR Result Interpretation & Clear Airways

[Steven Alexandro]

Hi Everyone,

First off, I'm so glad I found this forum -  I've learned so many helpful insights over the weekend reviewing other apnea-related posts! Really appreciative that there are so many active helpful participants sharing their knowledge and experience.

I've come to ask for some assistance - both in the OSCAR results I'm getting, but also recommendations for adjustments.

A bit of background. I've had 2 sleep studies, one that was an overnight in a hospital, the other which was a Lofta study. The hospital study resulted in correcting a deviated septum (AHI was ~6), the Lofta study last year resulted in a ResMed Airsense 11 purchase (AHI ~8). Both studies indicated mostly OAs, but there were a few central apneas. Pressure recommendation from Lofta was 4 - 20, but I gave up after a month.

All that said, I'm giving it another go and getting mixed results. Last night, for example, all events were Clear Airway (which is surprising). The AHI scores are low, but I'm still very tired with brain fog. I've been waking up twice each night to use the bathroom. I'm hoping I'm tired just because sleep duration isn't long enough, but I'm also hoping these aren't really CAs but something else? Also, I use mouth tape, an intake nasal dilator, and mostly sleep on my side (I think).

I've attached two zoomed out screenshots and one zoomed in on CAs from last night. Of note, last night I adjust my min pressure to 7 with EPR to 2. The previous were min 4, EPR 3.

Any advice or recommendations? Thanks in advance for anyone that can provide insights on how to improve!

[PeaceLoveAndPizza]

First, do you take any medications? Did you do a sleep study and if so could you post the results or summary page (redact your personal data first).

Initial CA's are typically treatment emergent, so we do not worry too much about them unless you had true centrals show up during your sleep study.

I suggest starting with a basic configuration and using that for a few nights, then posting some OSCAR charts for review. Folks can help from there.

Mode APAP
Min pressure 7
Max pressure 15
EPR 2 full-time
No ramp

That should tell us quite a few things, in particular whether the CA's are pressure support driven or not.

[Steven Alexandro]

Thanks for your response! Regarding medications, 10mg of enalapril in the morning for high blood pressure. I also take a beta-blocker as needed for infrequent bouts of SVT (1 per ~2 months).

Sleep study results in the screenshots below. The first is a brief summary from 2018 - the study occurred in a sleep center in an academic hospital. The second is from Lofta in 2023.

I will increase the max pressure to 15 as recommended and maintain 7 as the minimum. EPR is set to 2.

[PeaceLoveAndPizza]

Nothing significant in the sleep studies as they indicate you have a mild case of SDB. I see what I would call RERA’s in the OSCAR charts with the arousal breaths, but there may be other factors causing that.

Give the suggested settings a go and let us see how it plays out.

[Steven Alexandro]

Hi everyone,

Following up about 10 days later with an update and additional questions. First off, as recommended, I adjusted my settings to:

Mode APAP
Min pressure 7
Max pressure 15
EPR 2 full-time
No ramp

Unfortunately last week was about as bad as it gets sleep-wise for me - exhausted during the day, headaches, etc. - but I was also prone to taking off my mask in the middle of the night (still quite new to PAP therapy). That said, the past two nights have been my best nights of sleep in months. I tightened the fit of my mask's head straps, which seemed to help a lot. Also made the following adjustments:

Min pressure 7.6
Max pressure 12
EPR 1 full-time

My question is about the many 'clear airways' I experienced last night. Is it possible that these aren't really CA events, but just body position shifts where leakage occurs and I'm holding my breath while I get re-situated? Several of the CAs seem to follow right after a small spike in leak rate. 

Any idea what might be going on?

*Note that I was awake during the big cluster of CAs around 3:45am, so not relevant

[SarcasticDave94]

While your leak rate isn't bad, if as you say, leaks occur with movement, then the mask seal is less stable than it appears. It should tolerate a bit of moving about. Are you using any type of hose holder?

The Central Apnea flags can certainly be just simple breath holds while moving. You just had 4 Central Apnea on your test under pAHIc 4%, so these CA flags are either breath holds, treatment emergent Central Apnea, or a combo of both.

[Steven Alexandro]

Hi there, I appreciate your comment. I'm not entirely sure if my leak rate is good or bad, though I noticed there are leak spikes right before the machine picks up a CA event. My hypothesis is that the leak spike is a result of a positional change, but it's not something I can't confirm. In the event that the CAs are treatment emergent or legit central apneas, are there recommended settings to adjust (e.g. EPR)?

Regarding equipment, I use a ResMed N30i nasal cradle mask, though I also have a tube holder mounted on the wall to minimize tube disturbances.

Thanks!

[Dormeo]

I wouldn't worry about the CAs if I were you. The zoomed-in views show that you experienced arousal breathing before those CAs. Arousal breathing is deeper and messier-looking than regular asleep breathing. Often there's no way to know what causes arousals.

There are two theories about arousal breathing and CAs. One is that the deeper breathing slightly depletes the CO2 in your blood, which causes you to pause between breaths a little longer than usual while CO2 builds up to the level that will trigger a breath. The other theory is that sensors in your chest wall detect a larger-than-normal expansion of your rib cage and trigger a pause to get you back on track.

Either way, CAs can sometimes come in clusters, as deeper recovery breathing after a CA sets off a new one.

Bottom line: as the arousals become less frequent, so will the CAs. And for many people, the body adjusts its mechanisms over time, making it less likely you'll have CAs after arousals.

[Steven Alexandro]

Hi all,

Thanks to everyone that has responded with useful information and advice. I've made some adjustments since my previous post, yet unfortunately I'm still struggling and looking for this community's wisdom. The screenshots from last night are fairly typical, but despite having consistent AHIs between 2 to 3, most days I still wake with headaches and contend with brain fog / tiredness. On a positive note, I was suffering with painful aerophagia yet switching to CPAP mode and lowering the pressure has really helped.

Mode: CPAP

Min pressure 7.6
Max pressure 7.6
EPR: off

A few things about me.. I use an n30i mask, but I'm starting to think I'm too active of a sleeper for it to be effective (just ordered a p30i). I've woken up a few times needing to adjust the cradle to improve airflow. I also use kinseology tape every night, otherwise I'd be a horrendous mouth breather. I suspect that my jaw still drops slightly and have been pondering a SCC, but honestly have no idea if it'd help given that I don't seem to have positional apnea.

On average, it seems like 70% of my CAs are from arousal breaths, yet the other 30% may be true central apneas.

Lastly, if it's of any use, I've started a sleep diary (last screenshot). It's only 8 days of data, but I'm hoping to identify positive trends over the long run. I wear a garmin watch, hence the sleep score, step, and HRV tracking.

Any recommendations on how I can improve PAP therapy or restfulness would be appreciated!

[Dormeo]

Your sleep diary is awesome! Do you spot any trends yet?

Your leak graph is fine, but if leaks are waking you up, they're a problem. Your switch to a pillow mask is a good idea; the pillows tend to anchor the mask a bit.

EPR can sometimes increase the number of CAs, but it also can decrease flow limitations, which it did for you. Your CAs aren't really your problem; arousals are your problem. So anything that contributes to sounder sleep will be a plus, and for some (though not all) people, FLs can make sleep less restful.

With this reasoning in mind, I'd suggest re-introducing EPR as an experiment. You can start out with 1 or 2 and stay there for a few days, then try 3 if all goes well.