[Equipment] CPAP pressure fluctuating [FIXED]

[dkmk]

For a year I struggled to use my cpap machine (ResMed Airsense 10), and one thing that kept bothering me was rapid fluctuations in pressure. They did not occur during ramp, but after ramp they would begin randomly or if I sighed or moved. The rapid fluctuations (multiple times per second) were large enough to be felt in the nose and easily heard with the mask off. I did some research and came across two terms: EPR and FOT. EPR was turned off on my machine so it was not that. FOT (forced oscillation technique) is not supposed to behave like that - it is supposed to come on only after about 10 seconds of no breathing to test if an apnea is central or obstructive. I told my clinicians about my problem and they insisted that it was EPR (even though that was turned off) or that it was all in my head. 

THE FIX: I got a clinician to analyze the pressure output of my machine in person. The clinician’s external pressure sensor showed the fluctuations I was experiencing. The clinician said she’d never seen that before. We sent the machine back to ResMed and got the internal pressure sensor replaced under warranty. ResMed’s team concurred that the machine was faulty. 

I just wanted to put this out onto the internet so that it might come up on google if other people are having the same problem. It would have really helped me a year ago if I’d known this was an option.

[mswertfager]

Hi DKMK, 

Thank you for posting your fix. I am running into a similar challenge with the ResMed FOT. It repeatedly wakes me up in the morning when I hold my breath transitioning from light to deep sleep. 

How is the FOT treating you now on your repaired AirSense 10?

[SarcasticDave94]

Ramp will of course prevent any pressure differences. It's locked down to whatever the Ramp setting is.

There's several things that can affect pressure fluctuations. Leaks, events like flow limits, Hypopnea, Apnea. We could assist with the settings if you'd use OSCAR the free report app that will show your sleep data.

[dkmk]

So funny story, the fix only lasted a week before I started running into the same issue again, and that was not enough time for me to successfully fall asleep with the machine. However during that week it did seem to be better. FOT would turn on but only after I’d held my breath for over 10 seconds - which is what it’s supposed to do. As opposed to when it’s broken, I only have to hold my breath for about 3-4 seconds for it to turn on, which is about the amount of time I spend at the bottom of my breath before inhaling again so it turns on at every single breath. The pressure difference caused by the FOT also seemed to be less extreme when it was fixed.

I am waiting to get it fixed again, but it’s taken a really long time because I moved to a new province and all of the clinics here are refusing to serve me because I didn’t buy my machine from them. Lmao. The one clinic who agreed to serve me is forcing me to pay $150 for my free repair. But if all goes well I should have it fixed again within two months, and if it breaks again I’ll just send it back again and again until resmed gives me a whole new one. Currently I’m feeling really frustrated that so far I’ve spent almost $700 on cpap supplies and I haven’t been able to do any treatment because my machine just doesn’t work. 

Another thing I noticed with it when it was fixed is if you turn the air on with no resistance and just let it run empty, it detects that the mask is not on your face and stops running after a few seconds. When it’s broken, it seems unable to detect this and keeps running forever without even reporting a leak. 

I will try to remember to update in a couple months if the fix sticks. In the meantime I definitely think you should go to your vendor and get them to run pressure tests on the machine. Make sure they mimic holding your breath a little by blocking the hole for a few seconds.

[SarcasticDave94]

It seems like something isn't right with your setup, usage, leaks, or something. It sounds suspicious that you have bad sensor more than once. Sure it happens, but what you seem to describe is bad setup. Of course, without a free app like OSCAR charts to see what's going on, it's all a guess on your part and mine.

You can use it to see for yourself what it will display. Most do use it, and post charts. Members help with the setup.

[Deborah K.]

Yep, we need to see Oscar charts to offer you effective help.

[liuzilong]

I use s9 autoset, and I have the same issue. I breathe slowly and the FOT is disturbing. But based on what I see on the documentatio, 4 seconds is normal.

after a respiratory pause (4 seconds), small pressure oscillations (1 cm H₂O peak-to-peak at 4 Hz) are introduced for 6 seconds.