Why didnt my machine respond?

[wesozzzz]

Hi

I have been getting some good overnight  AHI readings  but my pressure usually sits between 18 to 20 cmw.

But last night I sat at a low pressure for hours and had clusters of events. Either I or the machine failed to respond  

Was I lying on my back?

Just curious , any ideas?

Thanks

   

[DeepBreathing]

G'day Wesozzz.

I think the machine is in fact responding. But it doesn't respond to the FR20 and FR50 events as these are an artefact of Oscar, not something the machine has reported. It also doesn't respond to central apneas, and it responds to obstructive events after the event is finished to prevent another one occurring (it doesn't have enough pressure to force an obstructed airway open).

So looking at the first part of the night you had a couple of obstructive apneas and hypopneas and a shedload of flow limitations. The machine has responded by taking the pressure right up to the maximum.

The second session is more complicated. Little or no flow limitations before 03:50. However you had a central apnea and obstructive apnea around 03:00, followed immediately by a period of Cheyne Stokes Respiration. The machine would have ignored the central and raised pressure slightly for the obstructive. But as soon as it sees the CSR it will hold the pressure steady again until the CSR is finished and you get another obstructive apnea.

[Sleeprider]

It would help to zoom in on the events from 03:00 to 03:15. We really don't know what is going on there. Although it is labeled CSR (more likely periodic breathing), the flow rate does not appear to fluctuate much, and events are mainly obstructive. It's interestng that there was almost no flow limitation. I have no idea what FR events are.

[Gideon]

The FR events are custom events set up in OSCAR'S preferences. They were renamed. I assume they represent 20 and 50 % Flow Reduction for a specified time. Would need to see the setup to be sure. These are unknown to the CPAP so it wouldn't respond to them.

[wesozzzz]

I set up the FR events as per wiki, FR20 and FR50 are Flow limitations 20% and 50% respectively.

Also attached is a blow up around 3 to 3.15 am.
I see my tidal volume  seems to be ok except for an occasional  drop so I guess I was getting enough O2, which is a most important  part of cpap.

   
Thanks

[Sleep2Snore]

I put up my low pressure slightly so there was not a lot between low and what the machine goes to.
Perhaps putting up your low pressure more towards what your machine sits at most of the time will help.
Maybe not the max, but take a high average of what the machine goes to and set it slightly below that and see what happens.

I suddenly had higher readings than I have ever had, I adjusted the low pressure slightly towards the high and I am back to low readings.
Not saying it will help with you, but it is well worth a try. It is also more comfortable if the low pressure is closer to the high, though in your case at 20 you will have to make a compromise. I used to be at 18, but since I got this machine (like yours) I am now at 13, it just went up slightly to 13.6 and so did my results. A slight shift in low pressure cleared my higher readings.
See my thread 5.0 to 0.1 & 0.0 in one step!
It is always worth a try, you can go back to where you were.
A collar may help you or a good chin strap or both and trying to stay off your back will help a lot.

[Sleeprider]

I set up the FR events as per wiki, FR20 and FR50 are Flow limitations 20% and 50% respectively.

Also attached is a blow up around 3 to 3.15 am.
I see my tidal volume  seems to be ok except for an occasional  drop so I guess I was getting enough O2, which is a most important  part of cpap.


Thanks

The event from 3 to 3:15 appears to be an obstructive cluster. If this happens a lot, then look to positional issues.  If it is infrequent, then don't worry about it too much.  It does not even appear to qualify as a periodic breathing event, so it's curious it got highlighted.