What happened last night??

[Chapalauser]

I started treatment 11 months ago and switched to an ASV from an Aircurve 10 Vauto in mid July 2019. My AHI with an ASV immediately dropped from 7 to close to zero. However, several nights ago I had a bizarre cluster that lasted about 40 minutes and resulted in an AHI of 5.1 for the night I have attached a screen shot of the episode.
I would appreciate it if the experts could shed some light on what happened.
Many thanks

[idlewire]

Looks like you're in ASV mode instead of ASVAuto with a fixed EPAP of 5. Since the machine can't raise EPAP, it can't help your obstructive apneas. Try switching to ASVAuto mode, Min EPAP 5, Max EPAP 15.

[Jas_williams]

I started treatment 11 months ago and switched to an ASV from an Aircurve 10 Vauto in mid July 2019. My AHI with an ASV immediately dropped from 7 to close to zero. However, several nights ago I had a bizarre cluster that lasted about 40 minutes and resulted in an AHI of 5.1 for the night I have attached a screen shot of the episode.
I would appreciate it if the experts could shed some light on what happened.
Many thanks

Can you provide the same screen shot with the mask pressure line rather than the pressure line at the same zoom level.

[Chapalauser]

Attached is a screenshot including mask pressure

[Chapalauser]

A closeup of mask pressure

[Chapalauser]

Looks like you're in ASV mode instead of ASVAuto with a fixed EPAP of 5. Since the machine can't raise EPAP, it can't help your obstructive apneas. Try switching to ASVAuto mode, Min EPAP 5, Max EPAP 15.

I think you are right. Previously, I had very few obstructives, a few hypopnias and almost 100% centrals so when I switched to an asv my ahi was close to 0 until I hit a night with a bunch of obstructives and my asv couldn't handle them as my epap was fixed at 5. I am not sure whether my sleep doc gave incomplete instructions or my dme misunderstood but it seems I am not in the asvauto mode. Being a relative nuby, I didn't notice.
I am seeing my sleep doc tomorrow as I need a prescription to purchase an asv as I am currently using a loaner. Should be an interesting discussion with my sleep doc and my dme.
Thanks for your input.

[Jas_williams]

A closeup of mask pressure

Your machine was using its max configured PS trying to make you breathe it failed, I don’t know why, the answer is more max PS epap will not help as these events don’t look to be obstructive in nature

[palerider]

They look obstructive to me, I'd raise the minepap.

[mason.smith1975]

Attached is a screenshot including mask pressure

Hi Chapalauser, I'm looking to get an ASV machine. It doesn't look like OSCAR charts show CA events for ASV machine, does it? If yes, how do you know central apneas are treated? Thanks!

[Pugsy]

Hi Chapalauser, I'm looking to get an ASV machine. It doesn't look like OSCAR charts show CA events for ASV machine, does it? If yes, how do you know central apneas are treated?

OSCAR can only show whatever data the machines show.
Respironics ASV machines will flag central apneas separately but ResMed ASV machines don't flag centrals separately. If something happens with a ResMed ASV machine in terms of either a central or obstructive apnea they all go in the UA or unclassified apnea basket.
The usual assumption with the UA category on the ResMed ASV is that the flagged events are obstructive because unless the machine has its hands tied with setting limitations that won't deal with centrals, they simply won't happen.
With ResMed machines FOT is used for figuring out central vs obstructive but the ASV machines don't do FOT. Hence no way to know the difference.
Despite this little drawback (some think it is a drawback because they just HAVE to see the category flagged) I still would recommend the ResMed ASV over the Respironics and I have had the opportunity to use both.
But if you are one of those people who just HAVE to know if you are for sure having a central apnea then you can get a Respironics ASV and it will flag it and OSCAR will then report it.

[palerider]

Attached is a screenshot including mask pressure

Hi Chapalauser, I'm looking to get an ASV machine. It doesn't look like OSCAR charts show CA events for ASV machine, does it? If yes, how do you know central apneas are treated? Thanks!

That's because you don't *have* central events with an ASV, the whole purpose of an ASV is to prevent centrals.