cpap machine stopped recognising apnea events, and now I wake up with them

[disp2]

For the last month and a half, I've had issues with my CPAP machine, a ResMed 10.

I've been using it for about a year, (and its predecessors for several years) and its been going quite well. I would sleep acceptably.

But now It seems to be not recognising or responding to apnea events, especially those which occur in the first half of the night. Instead of registering about 3-4 events/hour -- the previous average -- it registers around 0.3-0.7, and the pressure stays constant (at 7.2; I've currently set it at the range 7.2 - 9.4).

Now, my sleep is terrible -- I awake sweating, after about 3-4.5 hours, exhausted or with a false sense of rest, with a slight headache, and cannot get back to sleep. Its debilitating. But the ResMed thinks no or almost no apnea events have occurred.

(If I do get back to sleep, it is fitful, and in the second half of the night it might register as much as 10-16 events/hour. I've congestion issues from dust allergies, and I suspect some of those events might be me switching to mouth breathing without realising - it is a nasal mask. But in any case, the events show that some aspects of sensing still work. And its on the ramp setting, and successfully auto starts. I'm bewildered.)


What was striking was that this change in the machine happened suddenly - one day in late August/early September it went from 3/hour, the usual for for the past year, to 0.3-07 per hour, and it hasnt returned to the previous values - it is the machine that has changed, and not me.

I do not know if it is a sensor, or an algorithm, or what. I do not know what to do - is this a common occurrence? Is there a way of resetting the machine that might restore it ? Or a way of checking its sensors? Is there a setting that has changed?

( I do not know how the machine works, or if its behaviour is `learned' from the accumulated data - so that this is a consequence of my history, and clearing its data will reset it; or what.)

The machine itself thinks it is working fine, and so the support people at the NHS claim nothing is wrong with it. Which is frustrating, as is their lack of acknowledgement, never mind explanation, of this phase transition in the behaviour of the device.

Can someone help?? To fix it, so I sleep again, and to explain?

Thanks!!

[Dog Slobber]

Post graphs demonstrating your assertions.

[disp2]

Post graphs demonstrating your assertions.

Don't yet have an SD card, or OSCAR. Will get that over the next few days; it will take a while - thinsg are hard when sleep deprived. But more data much better, yes.

The numbers given are from the (rather inadequate) CPAP display, checked consistently over the previous two years on waking, 3.5 hours in, and subsequently throughout the night.

I hope they suffice to diagnose the issue, or to recognise it, or to even make useful suggestions! Any help or insight would be great.

(I've no mental model for how the machine functions, or even whether its behaviour changes as a result of stored data - does it 'learn'?)

Again, any suggestions or hypothesis would be very helpful!

[Dog Slobber]

Turn your machine off, wait a minute or so, and then back on.

What kind of apneas are they. The machine will not respond to centrals or unknown apneas. You can get unknown apneas if you have excessive leaks.

You are also making assertions that you simply can't know, without data. And then asking for advice based on assumptions.