Assistance getting sub 5 AHI on new machine

[Damiansd]

Hello,

New Philips Dreamstation Auto owner here. Last night was first night and it went pretty well. AHI of 7.31 and one wake up (toilet). I purchased it without the humidifier chamber and I think that was a mistake as it is noisy. I'll most likely go back and purchase that...

Overnight sleep study a few weeks back. The sleep tech said that 12 was the best for me. My doctor looked at the data and saw that OAs and Hypopneas dropped off at 8, so he prescribed 8. For initial night, I set Fixed on 8 to see how it went. 

Attached is the result as I wasn't sure how to insert it inline.

I'm open to moving to Auto mode, but wanted to do the fixed as a baseline first.

Thoughts?
Damian.

[Gideon]

Hello Damian,

If I were to look at a detailed flow rate I am very likely to see a lot of flow limitations.  Yes, the event breakdown does say no Flow Limits, but you have a number of RERAs. RERA is defined as a series of Flow Limitations ending in arousal.  Your RERA is 1.22 so your RDI = AHI + RERA = 7.31 + 1.22 = 8.53 

Hypopneas are your highest category at 6.49.  Hypopneas are treated the same way as Flow Limits and RERAs and that is with pressure support.  The closest you have to pressure support is Flex. Try increasing your Flex setting and see if that helps.  

Any chance you can trade this machine in for a ResMed AirSense 10 AuroSet?  ResMed's EPR, the 'equivalent' of Flex, behaves like pressure support in a BiLevel machine and is as effective as can be in an APAP/CPAP machine without getting a BiLevel (ResMed VAuto).  The AutoSet is limited to 3 cms of PS (EPR=3).  Unfortunately, PR machine do not perform as well against these events.

Otherwise there is nothing there I am concerned with.

I would try Auto mode with a min pressure of 8 and see what happens.  Max pressure 0f 15 just to prevent it from running all the way to 20.

[Damiansd]

Thanks Bonjour,

I'll move over to Auto Mode with min 8 and max 15. Back tomorrow with another graph.

I should have mentioned I wasn't using C-Flex at all last night.

Cheers,
D.

[Gideon]

Then add Flex too.

[sleepyp]

Out of interest, does CFlex or AFlex/CFlex+ perform best for flow limits/RERAs/hypopneas?

[Gideon]

All do poorly IMHO, flex is applied in a variable manner depending on how you are breathing. The bigger your breathe the bigger the application of flex. When your breathing is shallower, which is when we CPAP users need it because frequently it is the hypopneas and flow limits that make it so, that less flex is applied. ResMeds EPR, on the other hand, is a fixed pressure amount as is pressure support. Flex also tries to predict when to change from inhale to exhale and back again. As a result many PR users feel their breathing cut off before they are ready. ResMed waits for you to initiate your inhale and exhale, it follows your breathing better.

The other difference is that flex of 2 or 3 typically delivers a Max of about 2 cmw, never close to 3 cmw.

Feel free to try each and pick what feels best.

[Sleeprider]

I'll just add to bonjour's comments that you should try different flex settings while awake and decide what feels most comfortable. I always found any Flex setting at 3 caused a loss of sync between me and the CPAP, but settings at 2 or 1 were better. AFlex stays engaged longer during exhale than CFlex, but unlike Resmed EPR, the pressure tends to lead you back out of exhale rather than follow. This can give you the feeling it is cutting off exhale time. The best way to set it is to try different setting and go with what feels best.

[Damiansd]

Hello,

Thanks all for the feedback.

Last night I proceeded with Auto 8-15 with C-Flex on 1. It seems the night started well until I had a nature break and removed the tape from my mouth. After that it all started going down hill.

   

My initial read is that the lack of tape allowed an air leak. For the remainder of the evening the machine was trying to overcome the mouth leak. A losing battle really.

This morning I've sat with C-Flex on 1 through 3 and A-Flex similarly for 5 minutes each. Strange as it may sound, I found no flex the most comfortable. Possibly as I'm a long term CPAP user and am used to be smashed with unnatural pressures. C-Flex 2 and 3 felt like they delayed the change from exhale to inhale. A-Flex was fine when I was shallow breathing, but if I switched to a few large breathes I felt it try to end my breath and return to normal service. 

Going forward my flex preference is none, although I'll take any counsel from you wiser heads.

Regards,
Damian.

[Gideon]

Any chance you can switch to a ResMed?  Your response to flex is typical for PR users.  
Do you have a cervical collar lying around?  Your hypopnea and OA look clustered, which typically means that your chin is tucking.  Can you fashion some towels to hold your chin up, put an old tie through them and tie it around your neck.  an old tie because it will be a wide flat surface, to not dig into the neck.

Hypopneas, RERAs, Flow Limits are best treated with Pressure Support, a pressure difference between exhale and inhale.  Thus the trial of Flex, to achieve this pressure difference.  Much better done with ResMed and EPR.

[Damiansd]

Thanks Bonjour. Unfortunately I can't move over to a Resmed, I wish I could.

Cervical collar in hand. Tape at the ready Auto 8-15 with C-Flex 1. Changing one thing at a time at this stage.

Really appreciate the help,
Damian.