[Treatment] Am I on the right track?

[alshayed]

Just thought I should post an update and ask for some guidance. So despite that 2nd night on the bilevel being pretty good just at 5-25/PS 4, I was a little disappointed over the following few days that they didn't feel "as good". So after messing around for several days with little progress I bought a cheap oximeter and managed to keep it on all night. It turns out my SpO2 is below 90% between 1 & 2 hours at the 5-25/PS 4 setting even though my AHI was ~0.65. So I've been spending the last week titrating based on SpO2. Last night I got to ~21 minutes below 90% at 10-25/PS 4.

Does anybody have suggestions on how much time below 90% is "okay" or the target? I'm thinking about doing 12-25/PS 4 tonight but I was also thinking I might want to bump up the PS a little more. Not sure what the best next step is. Or should I stick tight and use my normal mask tonight and see what the results are?

Attached is a screenshot of last night... I was trying a new mask so please pardon the leaks, they aren't normal. I'm pretty much ignoring the CA's for now until I get the oxygen right and hoping they go away after I acclimate to the new treatment settings. Note I am overweight, it's possible OHS might be part of my issues. I was reading about the iVAPS devices and wondering if that's what I really should be using, but obviously I hope I don't need to go that far.

Thanks!

PS - If the right tidal volume target is 6 ml/kg I should have ~415 so that seems a little low, so that might be an argument to increase PS rather than EPAP.

[ajack]

Biggest problem is leak or mouth breathing, use a ffm while you work this out.
I'm unsure why you went to bilevel? It may not be the best machine for you. It has some CA now.
If it was my chart..I'd follow the titration guide in S mode
https://www.resmed.com/us/dam/documents/...er_eng.pdf

[alshayed]

Hi Ajack,

I apologize for not explaining well. I will recap the situation and hopefully cover anything that was missed along the way.

I started using CPAP in March 2018. Despite ~100% compliance and AHI well controlled (some days 0.00 even) I have not gotten a good night sleep since starting, or many years before using CPAP. It's nothing to do with the mask, I tolerate that just fine. Every day I am tired, some days worse than others. The last 9 months I have only been able to function with a prescription for armodafinil. My original diagnosis should have been in ~February 2017 but somewhere between the home sleep test company and my doctors office it took an extra year to get the results to me.

As I stated in my earlier post today, the leaks on this particular chart were a one time deal due to trying a new mask. With my normal mask I typically have no leaks, period. Please pretend that there were no leaks for the purpose of looking at this latest chart.

At this point I don't care to explain why I went to bilevel. Suffice it to say that the 2nd night on the new VAuto machine was the best night of sleep I have had in many years. So it's really just water under the bridge and you can pry it from my cold dead hands.

Unfortunately despite this I don't feel great. I tweaked the settings over ~2 weeks and didn't get anywhere so I finally did a couple of overnight oximetry tests. They revealed 10-16% of my sleep is spent less than 90% SpO2 which translates to 45-120 minutes out of probably 7 hours sleep on average. So presumably this has been happening the entire time I've been using xPAP - continuing hypoxia every night for who knows how many years, but I assume less hypoxia than before I started CPAP.

Right now I am asking for specific guidance on the best way to continue raising my SpO2 and/or when to stop messing with it, based on the assumption that getting >= 90% all night is my best shot at feeling "rested" someday. I've gotten it to the point where last night "only" had 21 minutes below 90% SpO2.

For several nights now I have been trying to methodically change settings and record results: (all IPAP max 25 & time is H:MM)

EPAP min 8 & PS 1 - 1:26 < 90% SpO2
EPAP min 7 & PS 2 - 1:33 < 90% SpO2
EPAP min 6 & PS 3 - 1:24 < 90% SpO2  (AHI 0.36 for example)
EPAP min 5 & PS 4 - 1:54 < 90% SpO2
EPAP min 8 & PS 4 - 0:49 < 90% SpO2
EPAP min 10 & PS 4 - 0:21 < 90% SpO2

Here are the questions I have:

1. Is there any amount of time <90% SpO2 that is considered "normal" or should it ideally be zero except during an apnea event? AKA "How much hypoxia is okay?"

2. Is my minute or tidal volume low enough that it's concerning?

3. What is the best bet at this point to raise SpO2 further? Ie do I follow the PEEP school of thought and raise EPAP further? (clearly that worked somewhat already) Increase pressure support per the S titration guide? ... I do feel like there is still some subtle flow limitations in my breathing that the ResMed algorithm doesn't always flag, and if I need to raise tidal volume then PS maybe is the way to go now for a night or two.

4. Am I chasing a unicorn with CPAP & BPAP-S? Is there evidence that I need BPAP ST-A (iVAPS) and I should stop wasting my efforts for now?

5. Am I missing anything obvious?

6. Is it reasonable to ignore CA's for now until SpO2 is >= 90% all night and hope they will subside as my body adjusts to actually being treated properly? Some of the CA's so far don't have SpO2 drops which seems weird to me.

7. Am I beyond the general knowledge of the forum and need to find a good pulmonologist with sleep apnea credentials to help me go further?

Thanks!
Alshayed

[ajack]

I missed that the leak was a new mask. If the vauto feels better, then that's the one you should work with. I was just comparing the chart on the last page with the apap, to this one. That's all. The other one looked better, but you sleep better on the vauto. The o2 is possibly raised by either machine. The vauto has more adjustment, but you now have CA around midnight. That seem real and possibly CSA that are causing further o2 drops. The forum normally suggests to lower PS for CA and a bit different to the guide.

Everyone should have a good pulmonologist. A forum can't replace a good doctor. Going by apap and Vauto charts, either may work for you. I don't think you need another machine like iVAPS that you asked about or ASV.

[Sleeprider]

You have achieved efficacy with your bilevel machine, and have relatively low AHI event rates. Your SpO2 is routinely 90 to 92, with occasional dips near 88. The correction of this may require the use of supplemental oxygen using an oxygen generator and oxygen bleed adapter on the tube. This requires a doctor's prescription. At this point, your concerns for low SpO2 should be directed to your physician rather than the forum. The solution is easy if your doctor agrees supplemental oxygen is needed.

[alshayed]

Thanks guys, and apologies it took a few days to get back. I'm going to go see my doctor in a couple of weeks and see how he wants to proceed. That will give me some time to "settle in" to the new pressure settings too and maybe have better perspective.

BTW I found my original sleep study and am kicking myself a little. It was pretty lame from a diagnostic POV, only 1.5 hours, but insurance wouldn't cover any follow up studies. But the part I'm regretting that I didn't understand better was where it said the AHI was 7.7 but the "RI" was 11.7. It appears that my test didn't give real RERA detection but they did at least try to give me something even though I didn't recognize it. Also 47% of breaths were flow limited w/o snore and 2% were flow limited with snores. So it should have been obvious from the beginning that I probably had an OSA/UARS combo, and on top of that 96% of the test period was <= 90% SpO2. Over half of the time was <= 88% SpO2.

Oh well I guess. I think I'm almost there if I can get the oxygen finalized but it sucks a little that my pressure has to be so much higher over what's needed to control the OSA.

[ajack]

Did you follow the titration guide? You stop raising the epap when the OA are controlled, or it can just increase CA. Back off epap if you have gone too far, You then raise ipap to clear the rest and check tidal volume, that helps o2. Then you look at o2 and raise epap again, depending on CA. It's a balance. CA clear up for most people within 12 weeks and yours are pressure induced.

[alshayed]

I have tried raising the PS instead of EPAP but I can't get my tidal volume to budge much when asleep. When I'm awake it's a big difference but as soon as I fall asleep the median sticks right between 380-400 no matter what and the SpO2 change doesn't seem like much. For some reason the EPAP/PEEP is working better right now. So far the max PS I've tried is only 6 though. Maybe the next combo to try might be 8-25 PS 8. Or perhaps 10-25 PS 8.


TBH I'm getting a little worn out trying different combinations and am going to take a couple of days off and stick with 10-25 PS 4. I've tried EPAP 12 PS 4 for a few nights which helped a little more (~10 min <90%) but now I'm struggling with mouth leaks. Thinking maybe I'll pick it up again this weekend. 

I do think the CA's are already getting a little better though so that's something. My PCP is probably going to send me to a specialist next based on my last conversation with him.

[ajack]

are you having trouble following the titration guide? It isn't a good idea just to guess. sometimes you may need higher pressure than OA, I would put up an o2 chart from the cms software. It isn't the total time in o2 deficit. it's how long for a period that may be more important.

You should be under a pulmonologist, to see if there are underlying issues. put up a chart, ps8 isn't that high, if you need it. My dad is on fixed PS10 most of the time and is common, with still a low tidal volume and high breath rate. I'm on variable ps5 up to ps18

[alshayed]

At a basic level I understand the titration guide and have tried to follow it to a certain extent but I have two issues: 1) I don't know the best way to convert it to a whole night vs how it's meant to work in a lab and 2) when I just increase PS alone that seems to have little impact just 1 cwp at a time.

For adapting the titration guide to a whole night I don't really understand what to do if you have conflicting events going on (OA, CA, H, and low SpO2 all together for example). Attached is a sample of the night I used 8-25 PS 4 for example. Now to be fair I'm not sure if that OA on the chart is accurate, I think sometimes I briefly wake up and take a few big breaths but hold my breath from there so maybe that's really a CA after micro arousal. According to ResScan that night I had 49 minutes less than 90% SpO2. There are sections of reasonably calm breathing like between 2:54 and 3:15 where the SpO2 is depressed. Is this the sort of night where you would just sit tight and see what a couple of extra days bring? Or make changes based on it?

On the oxygen front, I know that EPAP/PEEP increases oxygenation because it keeps more air in the alveoli giving more time for gas exchange along with a bit of a reservoir in case of apnea events, and it also gets more of them in the action without collapsing. I also know that increasing IPAP (PS) gets more air moving through increasing O2 gas exchange and washing more CO2 out. CA's can be caused if your CO2 is too low because that's what drives your ventilation response. So I understand that there's a balancing act, I just don't know how to figure out the balance.

When I bumped up to 10-25 PS 4 the next night the time under 90% dropped to 21 minutes. So I think I'm finding that I do need EPAP/PEEP somewhere in the neighborhood of 8-10 but probably need to fine tune PS from there. I think that my tidal volume should ideally be somewhere between 415 and 555 (6-8 ml/kg IBW) based on guidelines I've seen online (both Philips & ResMed, and studies/JCSM articles). However that's a pretty big range, but nonetheless I'm typically in the 380-400 range so it could probably come up.

Anyway maybe I am starting to figure out the balance and I'm just impatient and want to be done fiddling with things so I can get on with my life. Feel free to tell me to chill out and relax... that's kind of where I started to think maybe I need to just take a few nights off of fiddling and stick with something that maybe isn't perfect but still much better than prior results where I had 1.5-2 hours below 90%.




Thanks for sticking with me though, I really appreciate the help.