Zero AHI

[Evaret]

I have a Resmed S9 with the pressure set at 12. I have been on this machine for about 2 years and getting great nights' sleep

For the last 3 nights I have got a reading of zero (0.0) for AHI on the cpap machine screen. I was impressed with one night at zero but became skeptical at 3. Getting a zero reading is not only unusual but, in my case, unheard of. I have never had a zero reading.

I downloaded Sleepyhead which imported the data for about a month. It confirmed the zero readings. Peak AHI also shows zero for the last 3 days.The Statistics screen showed an average AHI over the last 30 days was 2.0.

There is data for all other areas - leaks, tidal flow etc etc. The other graphs show fairly consistent tracks over the month and show nothing unusual that I can see in the last 3 days

So before I spent my money getting the machine checked I would appreciate any thoughts from members on this.

Also my congrats to Sleepyhead - it is a great little program.
Cheers

[Pugsy]

The S9s have been known to get "stuck" reporting the same thing night after night and it seems like 0.0 is one of the favorite things to get stuck on. Try unplugging the machine from the electric source for a couple of minutes and then plug it back in. The forces the firmware to sort of reboot like we do computers when they get cobwebs.
Then see what tomorrow's report shows before worrying about spending money to get it checked out.
In most cases this fixes the issue and it's free and easy to do and hurts nothing to try.

[Evaret]

Disconnected and reconnected power last night. This morning I got a 'sensible' reading.

Thanks for the advice, Pugsy.

[jedimark]

Careful, sounds like your S9 is developing sentient abilities.

Maybe there was some corruption of the SD card in these cases?
Or there's a date/clock bug in the machine and it can't count hours correctly on those days.
Or there is the possibility you genuinely did get three in a row?

Did it create flow waveforms for those three days? If it did, try flagging them with SleepyHead's user flagging system in preferences, and see if the machine was obviously on strike.

[Sheriff Buford]

Maybe there was some corruption of the SD card in these cases?

Seems to be a glitch in S9's. I have to unplug and plug in my S9 a couple times a year. My cpap machine is a lot like me... gets stuck once in a while.

Sheriff

[RandyJ]

It happens to me with my S9 VPAP Auto... sometimes 3 or 4 days in a row of 0.0 AHI but everything in SH looks normal. Sometimes I unplug & reset but the last time I didn't and on the 4th day got a "normal" reading of 0.1. I think I am prone to events that don't meet the "10 second rule" or otherwise affect AHI.