New CPAP user - apnea worse with CPAP?

[rleaman]

Hi I'm a new CPAP user and it feels like it is making my apnea much worse; I would be grateful for any advice & thanks in advance!

My home sleep study showed an AHI of 17.0 on my back and 6.5 on my side. Doctor diagnosed obstructive sleep apnea. While I waited for the CPAP titration, I started using a consumer SpO2 monitor to help me troubleshoot my position and wake me if needed - and started feeling a lot better.

After the CPAP titration, I was prescribed home CPAP with a pressure of 9.0, but I feel massively worse every time I use it. I wake up desperate for air after a hour or two and even if I don't use it again that night, the next day I feel like completely awful (like I've been awake for 72 hours straight, drugged, and sick at the same time). I finally gave up entirely for a few days to recover, but still had to take two days off work because I couldn't do even basic tasks. 

When I use the CPAP at home, my SpO2 monitor shows repeated drops in my blood oxygen to the 80's, starting immediately as I fall asleep, and often repeating rhythmically after that. I wrote some code to compare the blood oxygen values while using CPAP and when not using CPAP (80k and 11k values, respectively; not a small dataset). Without CPAP my average SpO2 is 95.4, with CPAP the average is 95.3. That seems ok, but if we look at the percentage of readings below 90%, without the CPAP it is only 0.8% while with the CPAP it is 5.2%. If I slept for 8 hours, that would be 25 minutes with my blood oxygen below 90%. Is it reasonable to think that could be why I feel so awful when I use the CPAP?

At first, the doctor said that I just needed to relax, then that "internet equipment" is not reliable, then to increase the pressure to 11, then that I need to do a BPAP study if I can't "tolerate" CPAP. At no point did he look at the actual CPAP data and he seemed offended I'd treat a consumer SpO2 device as useful (I don't claim more accurate than his equipment, just better than nothing). I'm not sure if I do need to try something else or if this is a simple setting issue or faulty equipment. Or maybe the doctor is not trustworthy - I later found out he has at least one official reprimand for over-prescribing equipment - but at the very least I don't think he's listening to me at all.

I've attached a report from a ~1hour session of CPAP use (pressure set to 12.0, IPR=2, ramp up of only 5 min, starting at 8). The report isn't as nice as OCSAR, sorry, I didn't know Resvent was bad - but at least I have something! I also attached a chart from my SpO2 monitor for the same timeframe (despite the time settings being slightly off). The points with zero flow look to me like the correlate very well with the drops in blood oxygen. The AHI for this session was 23.3; if we assume I slept on my side, then it is >3x worse than the AHI in my home sleep study with no CPAP. Every time I use the CPAP while asleep looks similar - the only differences are (1) how long the flow stays at zero, which drives how low the SpO2 gets (min = 72) and (2) how regular the drops are (sometimes every 94 seconds).

Finally, I also attached the pressure distribution chart from my CPAP titration, which says my AHI actually goes up as the pressure was increased from 5 to 7, but then goes to zero (!) for pressures 8 through 11, with IPAP and EPAP always the same. I don't know how normal that is, but their results don't seem to reflect what I'm getting at home at all. 

I know this is a lot; would anyone have advice on what might be going on, if any of this looks weird/suspect or what to try (including get a different doctor)? Thank you so much!

[rleaman]

After continuing reading on the boards, I'm wondering if the pattern of not breathing and O2 dropping might be related to the treatment emergent central apnea issue, where hypocapnia causes loss of respiratory drive. But in my case, my body doesn't restart breathing until O2 is pretty low (<90%) and my CPAP (a Resvent iBreeze, unfortunately) is tagging these events as obstructive and as hypopnea, never central. I'm reading the wiki post on Enhanced Expiratory Rebreathing Space (EERS). Anyway, grateful for any feedback, thank you!

[Geer1]

Assuming this machine is comaptible with Osrcar if you download oscar and post some screenshots we can try to determine what is going on.

[Sleeprider]

I see you are using a Resvent, and the Oscar Development team is looking at that for future compatibility. The pattern of breathing appears to be central in nature. The pressure graph shows you are using some bilevel pressure or expiratory pressure relief. This will trigger central events in some individuals that don't experience CA with fixed pressure as was used in your sleep study. I would suggest reducing or eliminating the exhale pressure relief on your machine to see if it helps reduce these events. As you become more accustomed to using PAP pressure you can add back exhale relief for comfort and monitor its effect on CA evens.

[Geer1]

Ok I see that this machine is not compatible with OSCAR and looked closer at the data you provided. Treatment emergent central apnea (TECSA) does appear to be a possibility. Positional apnea may be another possibility.

It is kind of crazy how your AHI went up at first during the titration and then dropped from 82 AHI to 0 with only 1 cm pressure increase but you did have 3+ hours of sleep after that point and your AHI was low and SPO2 stabilized as well so it does appear that either the CPAP was working once you got to 8 cm pressure or that you changed sleep position or something to make apnea go away. The odd hypopneas you had at 12 and 13 cm pressure might have been central in nature due to the higher pressure potentially supporting that you are prone to TECSA.

One thing to note is that the titration study was done at fixed EPAP but you are using expiratory pressure relief (called IPR on your machine and which you have set to 2). IPR makes it easier to breath but it also makes TECSA more likely. Using the current combination of higher pressure (12 cm) and IPR is a potential double whammy and the first test should be to decrease pressure back to 9 cm and turn IPR off. If that fixes/improves things then these are most likely treatment emergent central apnea. If it doesn't help then you could consider trying a soft cervical collar to see if that helps (a common treatment for positional apnea).

[rleaman]

Geer & Sleeprider - thank you both very much for the response. My doctor is absolutely not listening to me, so I'm especially grateful for the assistance. It is correct that OSCAR doesn't support my machine, I'm using the iMatrix software.

I will try setting the EPR (IPR on my machine) to OFF/Zero and a pressure of 9.0 and see if that helps. I am quite certain (from other data) that positional apnea is a problem for me, though it isn't clear to me how much of a problem in general or how much it is this problem specifically. I did get a a soft cervical collar, though, and I'll be experimenting with that as well. I'll try these out a few nights and report back.

I was wondering about the pressure / AHI pattern in the titration study. Positional apnea sounds likely, thank you.