Advice for CPAP pressure and other -- complicated case

[dcg494]

Hi everyone, 

I'm fairly new to this board, but know you all are really helpful when it comes to figuring out problems with CPAP and treatment. 

I've been using CPAP for over three years and CPAP was retitrated at 7.5 mm pressure about 2 years ago. During that sleep study, anything above 8.5 pressure would increase my arousals a lot. I guess the assumption is that higher pressures induce unstable ventilatory response and that I have a low arousal threshold. 

So I stuck with 7.5 or 8mm pressure but had a sleep endoscopy to see where the airway restriction was occurring. Results indicated that I'd respond to a MAD. I can't use the MAD at full therapeutic levels since it changes my bite / jaw a lot. So I've been using the MAD at an intermediate setting together with CPAP, and I've felt a bit better since doing that. 

Still not great though. 

The more I research, the more I think I'm a complicated case. First off, I have UARS (upper airway resistance syndrome) not OAS and suffer from RERAs (i.e arousals) at night more than apnea. Indicating I have a low arousal threshold.         

I've been using a pulse oximeter for past six months and my SP02 hardly falls below 93-92% ever. Indication is that I may also have a high chemoreflex response (i.e. the sympathetic response we get to increases in blood CO2 levels / drop in 02). This means that even small drops in SPO2 result in arousals for me.

I'm attaching here a picture of a typical night with CPAP including heart rate. What I did in sleepyhead was enable flow limitations at 20 and 50% which adds flag events that otherwise wouldn't be there. Since I'm assuming I am more sensitive to any blood oxygen/CO2 changes etc at night, I think these more subtle flow limitations capture my problem better. 

My questions are: 

Has anyone seen a similar case before ? If so, what did they do ? 

Why do higher cpap pressures increase my arousals at night ? Why do they induce unstable breathing patterns ? Would a Bipap or a ASV enabled machine be an option for me ?

Thanks so much for any and all ideas / advice on this!

[Walla Walla]

From what I've read here a BiPap is the answer. It seems a large pressure support is whats required and a regular cpap isn't capable of doing that. I'm sure sleeprider will address this more.

[Sleeprider]

You are using a Philips Respironics System One Auto CPAP with a fixed CPAP pressure of 8.0 and Aflex at an unknown setting. Your results are therapeutically excellent. My guess is that your CPAP is nearing replacement age. With all due respect to the Philips products they make here in Murrysville, try to get the Resmed Autoset on the next machine renewal. You should be approaching 5 year, so you are due for a refresh. My suggestion is to request a Resmed Airsense 10 Autoset, mostly because the EPR gives a true bilevel pressure support of 3-cm. So your current pressure of 8.0 will have IPAP/EPAP pressure of 8/5. Your current therapy is pretty good, but I think that would put you over the top on comfort.

[dcg494]

Thanks for the responses both! 

 You should be approaching 5 year, so you are due for a refresh.  

I changed insurance recently with over a year of lapse in insurance (I'm live abroad a lot). I wonder how I can get my current insurance to pay for a new CPAP, anyone know ? 

My suggestion is to request a Resmed Airsense 10 Autoset, mostly because the EPR gives a true bilevel pressure support of 3-cm.  So your current pressure of 8.0 will have IPAP/EPAP pressure of 8/5.  

I was actually thinking of setting off the EPR. I'm at a loss to figure out the persistent tiredness, but have a feeling the EPR destabilizes my breathing pattern. Should I try w/o EPR at maybe 7 pressure ?

Your current therapy is pretty good, but I think that would put you over the top on comfort.

That's the crux! it LOOKs like it's good, but it's definitely not. I feel horrible most days, extremely tired. Pushed up the sensitivity on the UF#2 to 60% -- I am sure that w every gray flag I have a microarousal.

My last sleep study found 40+ arousals per hour, but they were happy when they lowered the AHI and RERAs a bit (still with a lot of arousals) and sent me home. Anything above 8cm pressure ruins me and I'm at a complete loss. Tried MAD, etc.

Is there nothing else that can be done ? 


   

[Sleeprider]

Your Philips Respironics machine uses Flex for expiratory relief. I'm saying the Resmed is completely different and not comparable. I frequently suggest turning off Respiraonics CFlex or Aflex, but Resmed EPR is a different deal altogether.

[dcg494]

Your Philips Respironics machine uses Flex for expiratory relief.  I'm saying the Resmed is completely different and not comparable.  I frequently suggest turning off Respiraonics CFlex or Aflex, but Resmed EPR is a different deal altogether.

Hi Sleeprider, thanks again for following up. Yeah, finally understand why c/a-flex doesn't give the 'true' pressure support as EPR would, thanks for pointing that out, super helpful.

I also read more on FLs and difference b/w FLs at inhalation and exhalation since these are my primary issue at this point. 

Do you think a higher EPR would help reduce exhalatory FLs ? Meanwhile, I could maybe tolerate a slightly higher pressure which would help reduce inhalatory FLs ? What do you think ?

[Sleeprider]

With the philips machines, increasing minimum pressure is really the only tool you have. If you are comfortable with that, the I would expect improvement in obstructive events including FL and H. With the Resmed, increasing EPR along with adequate minimum pressure acts like bilevel and generally helps. This article by Dr. Barry Krakow on an Apnea Board Wiki is a good read and explains more why this works. http://www.apneaboard.com/wiki/index.php..._and_BiPAP

[dcg494]

Extremely helpful, thanks a lot Sleeprider! I'm definitely in that group of people w UARS, it feels really good to have (hopefully) an answer, at least a lead.

I'm convinced I need to try EPR -- or BiPap.

I'll either get the Airsense 10 (for her) or the Aircurve 10 VAuto. Final question, maybe you or someone can help with it -- which should I get ?

Dr. Barry says most UARS patients need a 4cm or higher IPAP-EPAP difference. Is it safe to assume I might need the extra 1cm PS, and just go with the 10 VAuto ?

Or do you think the Airsense 10 with EPR up to 3 could cut it ?

Unfortunately where I am at, the standard return policy for CPAPs is within 3 days, so it's not like I could try the airsense and then switch to vauto.

The Airsense 'for her' has an interesting auto algorithm that adjusts the pressure up gradually with every flow limit. Not necessary probably but was looking forward to trying it..

[dcg494]

Maybe this additional bit of info will help -- my required pressure is probably in the 9-10 range, since 8 seems to control the apneas but not the FLs. I just could never tolerate anything beyond 8cm, I assume because c-flex doesn't provide enough PS (and maybe b/c higher pressure exacerbated expiratory FLs?)

So maybe 3cm EPR would be enough if all I need is 9cm IPAP. If i need 10-11cm IPAP, I may need pressure support of 4cm --> I.e. I might need a bipap, the Vcurve.

Given the uncertainty, I should probably go with the Vcurve ?Does that sound like a sound assessment ?

PS: I can't have another sleep lab study to figure it out, my insurance won't cover 'sleep apnea'. So have to do it on my own.

[Sleeprider]

If you have the option to use bilevel, it is clearly more flexible and capable of providing pressure support. For pressure, we use EPAP to control OA, and once that is resolve, we add to the IPAP pressure (pressure support) to control hypopnea, flow limits snores and RERA. We back-off pressure support in the presence of centrals. That is the general approach, and if you can tolerate higher PS without centrals, your chances of eliminating upper airway restriction is very good.

I would rather see you with bilevel but it's surprising how many people have had decent results with the Resmed Airsense 10 and its EPR. To be clear, EPR is considered a comfort feature, not a therapy, but it works a lot better than Flex.