Sierra

My wife experiences large leaks fairly frequently. However I see no impact on her mask pressure or on AHI. See this example. Perhaps her large leaks are not large enough...

I am afraid I have not explanation as to why that would be. I do know some report the autostart feature to be somewhat flakey.

This machine flags flow limitations instead of just displaying the flow limitation graph like a ResMed machine does. I think that method makes flow limitations appear worse than they really are.

With the machine set to pillows a smaller amount of flow would be subtracted from the total flow to give a larger leakage flow, but it should not impact the autostart feature.

I am not of the opinion that large leaks have a significant effect on AHI. Unless the leak is really large, like the mask fallen right off or away from the face, the machine can still maintain pressure with a high leakage rate. My wife has large leak issues but I have never seen them that bad that mask pressure is not maintained. If you have a ResMed machine it will display mask pressure and you can check to see if it drops off by using OSCAR.

What does change on a ResMed when you have a large leak is the identification of the type of apnea event. During a large leak (greater than 24 L/min) the machine cannot distinguish between OA and CA events, so it calls them UA events, or unidentified apnea. Because it cannot distinguish the type it simply holds the pressure, because increasing pressure in response to a CA event would be inappropriate. So the worst thing that can happen is that you need more pressure and don't get it because of the leak issue. Then what may happen when the leak stops you get a few OA events right after the large leak ends.

I also think positional issues and large leaks are quite unrelated issues. You cannot eliminate apnea events related to position by stopping large leaks.

OK. I find that OSCAR is all I need to track my sleep. That of course needs data from a CPAP to work though.

https://www.sleepfiles.com/OSCAR/

What do you mean by a "sleep app"?

Here is the vent flow specification for the Evora. At 12 cm pressure the vent flow is 35 L/min

Here is the vent flow spec for the ResMed F40 mask which is very similar. At 12 cm pressure the vent flow is about 36 L/min. So almost exactly the same. ResMed recommends the "Pillows" setting for the F40. The Evora is just slightly less flow, so the Pillows setting would also be appropriate for it too.

These diagrams can be found in the user manual for each of these masks.

The only adjustment the A10 makes is the amount of vent flow that is subtracted from the total leakage to determine the leakage in addition to the intentional leakage flow.

Leaks over the leak rate redline of 24 L/min show as grayed out areas in OSCAR. During leaks this high the machine cannot reliably distinguish between central apnea events and obstructive apnea events. For this reason ResMed (if that is what you have) suspends the classification of events, but I believe still reports them as Unclassified apnea events, UAs. Because it does not know if the event is obstructive which indicates the need for more pressure, or central where more pressure is inappropriate, the machine takes no action on pressure, and just holds it where it is. So, in some cases if the pressure is not high enough, more events can occur, and when the large leak ends pressure may be too low and a series of events can occur. What affect does this have on AHI? I am not that sure. My wife suffers from significant leaks and I am not sure it hurts her AHI.

The other thing to check when when a large leak occurs is how well the machine holds pressure. If you have a ResMed which displays Mask Pressure in OSCAR, that is a good indication of whether or not you are losing pressure. If you have a DreamStation machine I don't believe it reports Mask Pressure, so that check is not possible.

If you post an OSCAR daily report with your high event issues I can comment. But, the first thing that comes to mind when there is a quick succession of OA events is a positional problem, like a kinked neck. If this is a problem some gain amazing relief by wearing a soft cervical collar. This was the case with another poster here that I worked with. He started using a soft cervical collar and brought his AHI down to very good levels. See this thread. It is a long one, but the poster stuck with it and got good results.

https://myapnea.org/forum/increasing-stage-3-and-rem-sleep