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EPR, Central Apnea, and Aerophagia - rpierce - 09-02-2023
My initial CPAP experience involved pretty extreme aerophagia. After complaining about it to the sleep tech, they changed EPR from Level 1, Ramp, to Level 2, Full. It made a massive difference and greatly reduced my symptoms.
After two weeks on the machine, I took three weeks off to recover from sinus surgery. I've now been back on the machine for about 2 weeks. My AHI's pre-surgery seemed to be near 16, and post-surgery they were: 9.02, 11.56, 6.45, 3.87.
Then I had an appointment with the sleep tech. She was honest with me that they're not sure if APAP can treat my central apnea. If I get stuck in the AHI 5-10 range on APAP without further improvement, they can bring me in for another sleep study and titrate me on an ASV machine.
Because I still had minor aerophagia and felt difficulty at times breathing through my nose, the tech raised EPR to 3. I'd also noted that when the machine was at low pressure and I was awake, I could barely feel EPR because there's a floor of 4 and my therapy pressure was 5-15. We raised that to 6-15, so (after the initial ramp which I have set to 5m) I'm getting a minimum EPR of 2 at all times. This felt better for me, both going to sleep, and on waking up in the night. I wasn't having anxiety and having to get up and off the machine in the night, and was able to do a single continuous mask session. And I wasn't detecting any aerophagia symptoms.
Unfortunately, my AHI on EPR 3 seemed to trend worse: 7.97, 9.96, 4.36, 5.63, 3.35, 5.40, 5.67, 6.60, 5.75, 6.62
Last night I decided to try an experiment. I was wondering if the EPR change made things worse, so I lowered EPR from 3 to 2. While I had no problems getting to sleep, it felt terrible on waking up in the night, like I was struggling to breathe through my nose. It felt like I was waking up more and having a harder, longer time getting back to sleep. I was experiencing minor aerophagia symptoms, too. I was about to chalk it up as a failed experiment, but I saw my AHI was 2.22, the best I've ever had, and better than where they could get me during my sleep study titration by a factor of 2.
I'm also not understanding the mechanism of what's happening. From what I've read here, the danger of high EPR is that it encourages hyperventilation, flushes out CO2, and that triggers CA's. But I don't see the hyperventilation happening. Two consecutive night's data:
EPR 3, AHI 6.62: (median/95%/99.5%) resp rate is 16.80/19.80/23.77 and tidal volume is 320/660/920
EPR 2, AHI 2.22: resp rate is 16.80/20.00/24.60 and tidal volume is 340/680/960
So my respirations look like they're basically the same on EPR 3 or 2, yet my AHI dripped to 1/3 of where it typically was. So I'm questioning if I'm really breathing more air / flushing more CO2 on EPR 3 vs. EPR 2 and wondering what caused this drop in AHI?
Qualitatively, it seems when on EPR 3, my CA events shifted to being more spaced out during the night, while on EPR 2, the CA's tend to cluster together following going to bed (sometimes; I'm more frequently able to go to bed without triggering CA's) or following times where it looked like I woke up, probably rolled over (to mitigate hip pain) and tried to get back to sleep.
So I'm debating if I should learn to live with the discomfort of EPR 2, assuming the AHI stays low, and assuming i can learn to get to sleep more easily when I wake up? Or if I should try to see if I can get my AHI down over time on EPR 3, which feels better, and try to switch to ASV if I can't?
RE: EPR, Central Apnea, and Aerophagia - Sleeprider - 09-02-2023
It's helpful to see the charts, but I would use settings that provide the greatest comfort rather than higher aerophagia. Therapy related CA tends to diminish on its own with adaptation to the ventilation, so don't let that stop you form using EPR. There is a pretty far-out way to actually increase CO2 by using "enhanced expiratory rebreathing space" (EERS), which conserves a small volume of exhaled air in the CPAP tube for rebreathing on the next breath. It works, but takes some DIY chops. https://www.apneaboard.com/wiki/index.php?title=Enhanced_Expiratory_Rebreathing_Space_(EERS)
RE: EPR, Central Apnea, and Aerophagia - rpierce - 09-02-2023
Thanks for the info!
I’m not sure if it makes a difference, but my diagnosis is CSA-CSR. My untreated results in the lab were: AHI 112.6, out of 152 events, 102 were central, 38 mixed, 4 obstructive, 8 hypopnea. So I’m wondering if the increased CA’s on EPR 3 are therapy induced, or a failure to treat the underlying CSA condition.
Not gonna lie, waking up with the bloating feeling of aerophagia and the feeling like I can’t properly breathe both give me anxiety. I’d been viewing daytime as momentary distractions between time spent facing The Machine. Being on EPR 3 had been doing wonders for that anxiety to the point where this all was actually beginning to feel normalized, and I wasn’t approaching bedtime with dread. So I’d feel a lot better staying on EPR 3 and hoping that over time the CA’s will come down.
RE: EPR, Central Apnea, and Aerophagia - rpierce - 09-02-2023
What charts specifically would be helpful? I’m happy to post them, but I see there are attachment quotas, and I’d rather post exactly what’s needed.
RE: EPR, Central Apnea, and Aerophagia - Sleeprider - 09-02-2023
Needless to say, your diagnosis is very relevant. Nearly everyone with complex or central apnea is started on CPAP due to the much lower cost. The Autoset just happens to be a bilevel in disguise with pressure support renamed EPR and limited to 3-cm. The gold standard for treating complex apnea is the ASV, but when aerophagia is present, therapy often is a compromise between resolving apnea and preventing intolerable pressure that causes air ingestion.
There are tutorials for Organizing Your Oscar Charts and posting attachments in my signature. Start with standard charts showing events, flow, pressure, flow limits and leaks, and if we need something else you’ll be the first to know. The EERS wiki has links to a first hand account of a member that resolved central apnea with this approach. Read carefully, and if you decide it’s not for you, we will focus on optimizing CPAP or helping you get ASV.
One more important point. The Aircurve 10 Vauto is a bilevel machine that is much easier to get, and less expensive than ASV, and it can be setup to have similar pressures as your Autoset. It has a poorly documented feature called trigger sensitivity that can help stimulate a spontaneous breath in individuals experiencing mild or moderate central events. It simply makes the machine more sensitive to subtle respiratory effort causing it to trigger IPAP (inhale pressure). This stimulus is often enough to resolve CA events in certain patients. Most complex apnea patients do best with ASV, but IPAP pressure can be a bit higher.
RE: EPR, Central Apnea, and Aerophagia - rpierce - 09-03-2023
Thanks again for the response.
I've attached a chart from Aug 31, which is my 10th consecutive night on EPR 2, and Sep 1, which is my first night on EPR 3. Of note, I've been making a point to roll over to try to reduce hip pain whenever I wake during the night, which does take a bit of conscious effort moving the hose (a hose hook is on my to do list) and a pillow between my knees.
I'm on the fence right now with EERS. On one hand, it makes a lot of sense. The theory seems sound. I'm interested if my charts indicate I might be a good candidate for it. If I can have the comfort of EPR 3 and still cut my CA's, I'd be very happy. I'm also a "maker" and am quite handy with hacking things.
On the other hand... I don't see anything specific to my mask type. Mine does have a swivel and uses a short hose before connecting to the supply hose. This design concerns me somewhat in that moving the vent / anti-asphyxia valve further down the line makes me question if I could roll over on it or somehow obstruct it accidentally, vs. having it on my face which I'm not likely to obstruct. I also am working actively with sleep docs, and I am concerned if I explained what I was doing, they'd be... less than amused.
RE: EPR, Central Apnea, and Aerophagia - rpierce - 09-03-2023
Correction: Aug 31 is my 10th consecutive night on EPR 3. Sep 1 is my switch to EPR 2.
Also... assuming cost / insurance isn't issue, would it be better for me to be on APAP + EERS or switch to ASV? And is ASV going to be more likely to be less comfortable and activate my aerophagia? (I have gastric reflux, and am on omeprazole, but it's fair to say my esophageal sphincter is a bit worse for the wear.)
I went back to EPR 3 last night, and AHI jumped back up to 5.64
RE: EPR, Central Apnea, and Aerophagia - Sleeprider - 09-03-2023
rpierce, using EPR may turn out to be to your advantage in the long run. With a diagnosis of CSA, you really should be using an ASV to maintain respiration when your spontaneous effort does not drive respiration. If you are not uncomfortable with the centrals, it is better to let CPAP fail by allowing AHI to remain moderately high until your doctor comes to the same conclusion I have. ASV would stop your events 100%, and there are ways to fine-tune it to avoid very high pressure. I would far rather see you using ASV than a "fix" like EERS or being less comfortable without the EPR.
With ASV you would use a low EPAP pressure to keep your airway patent. 5 to 6 cm seems to be enough. Pressure support (PS) would be used for comfort (PS min 2.0 cm) and to trigger a breath when you don't (PS max 7-8 cm). In this way, you could avoid very high pressure to protect aerophagia, and still treat centrals. What is important for you to know is that you must "fail" CPAP by having a high AHI, especially central apnea, or not tolerate CPAP. Without a determination that CPAP fails to provide efficacy and that a higher level of PAP like ASV is medically necessary, insurance won't cover. Here is a wiki article explaining the justification of advanced PAP. https://www.apneaboard.com/wiki/index.php?title=Justifying_Advanced_PAP_Machines
RE: EPR, Central Apnea, and Aerophagia - rpierce - 09-03-2023
Thanks so much. This is really good info.
I’ve become fairly chill about the machine, at least if I’m on EPR 3. I used to be very aware of CA’s while falling asleep, and I’m becoming less aware of them with treatment, even though I can see in the data that they are definitely happening. So I can tolerate the CA’s until my next appointment.
I’m working with a sleep center that seems open to prescribing ASV. They set up a 6 week follow up appointment, and the treatment plan their sleep tech expressed was to wait and see if my AHI falls below 5, and if not, come in for an ASV titration. Given that on EPR 3, after two weeks the trend seems rather consistently in the 5-10 range, I’m guessing that won’t change in the next 4 weeks. And the change to EPR 3 was their sleep tech’s suggestion, not mine, so all this has happened using settings they approved. Waiting 4 more weeks, “failing”, and getting an ASV sounds like a good option. I’m also really fortunate; I’ve blown through my out of pocket maximum for the year, so it seems the next sleep study is going to be free.
As for the necessary other symptoms, I’m waking frequently. Usually I sleep 1-2 hours and consciously wake up. Could the CSA be responsible for this frequent waking? If I actually go out for 7 hours, I’m not rolling over, and I am concerned with what it’s going to do for the hip pain that I only started experiencing once CPAP got me sleeping for long enough periods of time that I wasn’t moving.
RE: EPR, Central Apnea, and Aerophagia - Sleeprider - 09-03-2023
Well, keep things moving along with awareness of your deductible calendar year. It is clearly in your interest to resolve this in the current year and avoid a rental that spans into next year, if possible. You have a great attitude towards this. While you're chill, it will be helpful to emphasize the CPAP treatment feels intolerable with all the events and leads to fatigue and other issues. More than one member has found the squeaky wheel gets the grease when it comes to ASV.