[Treatment] Most events are Central Apnea / Clear Airway

[joeblough]

hi all

i've been using an airset 10 for about 3 months now. prior to therapy, WatchPAT AHI was about 9, and in-lab PSG AHI was about 20. my treated AHI is about 3.6, but it turns out this is almost entirely cental apneas. i have vanishingly few OAs - the machine does register flow limitations, increasing the pressure and almost completely preventing obstructive events. a lot of the OAs that are logged occur in the middle of runs of CAs, so the machine has probably misclassified those.

these CAs look to be transitional - they occur as i am falling asleep and when i change position. i see minor versions of these in my o2 sat data when not wearing the CPAP. with the CPAP, the CA events cause deeper and longer o2 sat drops - bouncing down into the mid-80%s and sometimes lasting for 15 minutes. without the CPAP there are maybe one or two drops into the high 80s or low 90s, and then they stop until i wake up and fall asleep again.

i still feel terrible in the morning and indeed all day - headache/face-ache around maxillary sinus, and dizziness. my compliance was not super good for most of those 3 months, with an average therapy time of 4h. recently i started forcing myself to not take off the mask in the middle of the night, and i'm now at 6-7.5 hours per night. i think sleep-wise i do feel better with the longer therapy time but overall i feel just as bad.

at followup the doctor reduced my pressure from 7-11 to 7-9 based on the average pressure recorded. perhaps the lower pressure has allowed me to keep the mask on longer, not sure.

with total AHI < 5 they don't consider this a treatment emergent central apnea. i am left wondering if it's the low o2 sats during the CAs that are causing my continued grief, or if it's just that i can't tolerate something blowing air into my head all night and am having sinus-related headache and dizziness during the day.

opinions? thanks.

[SarcasticDave94]

Do you have your sleep study detailed report? If not, you need it for yourself. Then you might want to post a copy of it here, that's been redacted of personal info. Maybe the Centrals were present in the test.

[joeblough]

i do have it; the event breakdown is as follows:

3 OAs (1.1)
0 Mixed (0)
2 Centrals (0.7)
45 Hypopnea (16.1)
21 RERAs (7.5)

total AASM AHI is 17.9 (so i mis-spoke above)

granted the TST was only 2:47, the study did not go well for me.

no N3 sleep was recorded.

so anyway the overwhelming majority of events were hypopneas and RERAs, not OA or CA.

[SarcasticDave94]

OK you had some of both Obstructive and Central, though not many of either. Many more Hypopnea. Next step is another OSCAR chart to go with the issue. It may be the CPAP is increasing the CA count, in that case you'll probably need to edit settings to try and avoid some of the CA, but at the cost of possibly hindering Obstructive and Hypopnea treatment effectiveness.

[joeblough]

well my pressures are already pretty low - they prescribed 7-9 but i think i'm at 6.4-9. what other settings can i tweak to avoid CAs? my understanding is that the machine can't go any lower than 4, so with EPR set to 3 (as i have), any pressure lower than 7 does not really result in an EPR of 3. i've also heard going much below 7 is not recommended for an adult male.

i wonder if the machine would not increase pressure during the ramp time? i have the ramp turned off right now. what happens is i get a huge run of CAs as i'm falling asleep and occasionally the machine interprets one as an OA and it increases the pressure erroneously. not sure if that's really a problem though.

[SarcasticDave94]

I haven't mentioned any settings edit just yet. Some people that have Centrals, either on the sleep study or while using CPAP, might be sensitive to variables in CPAP pressures including Ramp, EPR, and may need closer to static pressure. It would be good to see the OSCAR data to help see patterns.

About Ramp, as I recall Ramp keeps the machine at that pressure for its duration. The Auto Ramp option affects the time only I'm thinking.

[HalfAsleep]

IMO pain around the maxillary sinus and headache may be a mask issue, and not an apnea or CPAP issue. I've had this happen if my straps are too tight, or if the mask style sits in the "wrong" place on my neck, jaws, and face. I've had to try different styles, be sure to have the straps not too tight. If I can only prevent leaks if the mask is super tight, I have to go to a different mask. I also use Pad-a-Cheeks for my straps to minimize them cutting into my face or neck.

[joeblough]

i'll post some screenshots of a typical night.

i have been fiddling with the mask fit - i think maybe it needs to be somewhat loose to prevent it from waking me up. i do have some leaks with it set the way it is now, but i still have the maxillary pain/headache.

so far i've tried the nasal cradle from resmed, the evora hybrid full-face mask, and i'm going to try a philips hybrid full face mask. i do breathe thru my mouth, so if i use a nasal cradle i have to tape my mouth and the doctors really don't want me doing that, though i understand it is very common. i am going to try the somnofix tape as it seems somewhat safe with the vent.

i think if i'm woken up at all during the night, my sleep is completely shot. last night i got woken up at 3:45AM and despite wearing the CPAP all night, i feel like i haven't slept in days right now.

i re-read some of the doctor's notes, and they think that sleep disordered breathing is leading to fragmentation. it could be the case that the o2 drops have nothing to do with my problem - i had assumed that the path was SDB/Apnea -> o2 drops -> arousals -> fragmented sleep, but it might just be SDB/Apnea -> arousals -> fragmented sleep in my case.

[joeblough]

well, i haven't made the screenshots yet, but i did read the wiki about this and noted sleeprider's advice. i lowered my EPR from 3 to 1 and with the dreamware hybrid FFM, i just had AHI = 2 and AHI = 1 over the two nights since i made the change. this is down from an average of about 3.5. the CAs are still occurring with position changes but they do not cascade and the o2 sat recorder trace looks a lot more like what it does when i'm not wearing the CPAP.

so this looks to me like i've just got the 'high loop gain' problem in the CO2 feedback loop. higher EPRs must be allowing too much CO2 to exhaust, and then i stop breathing.

still have the maxillary pain - was investigating the idea that i could have allergies but have been on flonase and azelastine for 3 days now without much change. i did tighten the mask a little bit last night and my leak rate and AHI were better than ever, but it could be that i have just tightened it too much. the day prior i didn't have headache/sinus pain but today i do.