Sierra

I thought the DreamWear full face connects at the top?

I suspect that the settings that are best at 5000 feet will also work at 500 feet, and should give better results.

This is a company that may buy it, if it is not too old.

SecondWind CPAP

An AHI of 7 is in the mild range of apnea (5-15), and not much above the top end of normal (5). Not really unusual that oxygen desaturation would be normal.

I think if there is some economic way to try an APAP that is much more informative than an expensive sleep study. Yes, pressure can make centrals worse. The basic idea is to use the lowest pressure possible to treat the obstructive apnea and RERA without causing an increase in central events.

The issue is whether or not PAP treatment will be worth it for you. Have a look at other threads in this forum from those who have RERA and marginal apenea. Some success with PAP and others do not. There is a certain amount of discomfort with using a PAP machine, and the benefits have to offset that discomfort to make the net result positive.

On machines I am bias. I think the best APAP on the market is the ResMed AirSense 10 AutoSet For Her (even for males). It has an optional algorithm that can work well for those suffering from RERA and on the margin. It can also be changed into the regular program mode, and does not cost any more than the standard AutoSet.

If at all possible try to get into an arrangement where you can just do a trial with the machine, and also have the ability to try different masks. The mask is the often the most difficult part to get right.

Sedative type meds and especially opiods can cause central apnea in particular.

Yes, one big attraction is that used CPAP's don't need a prescription.

I am afraid I am not the one to give advice on making full face masks seal. I couldn't do it, but was using pressures near 15 cm when I was trying it. Hopefully someone with that specific mask can give you some help. I have resorted to mouth taping and a P10 nasal pillow. Also using a fixed 11 cm of pressure.

On your sleep onset apneas you might want to try eliminating the ramp if you can go to sleep with the 11 cm of pressure. If nothing else it will allow the machine to report the apnea and identify what type of apnea it is.

However, for comfort I would use the auto ramp. It has the advantage of holding the pressure to a comfortable level that you select, and then increasing it when you go to sleep. One issue with the timed ramp is that it will go to the end of the time period even if you go to sleep. Then you could have an apnea and the machine will not respond to it. It ignores events during the ramp.

Some observations:

• Your last image does indicate what looks like fairly normal sleep.
• Your second image looks like you were not asleep and the event may be what is sometimes called sleep wake junk. The mask pressure shows positive testing for obstruction. So it may be a legitimate sleep apnea obstruction, or you were just holding your breath for some reason. There looks like some very minor mask leakage which may have been disturbing you, but it is not excessive. Leaks over 24 L/min are excessive, but you were no where near that. You actually had two events in a row, but the first one ended before it got flagged.
• Breathing is more regular in the first image, so you may or may not have been awake. Similar minor mask leakage. It looks more like a legitimate obstructive sleep apnea event.
• Your pressure is not going very high, so the machine determination of need for pressure is low. You are not going anywhere near your set max of 10 cm.

As we discussed before, I would set the machine to use an Auto Ramp with a start pressure of 6 cm, and then set the EPR to ramp only. That will let you start with the full 6 cm on inhale and it will cut back to the 4 cm on exhale. After you go to sleep the machine will increase the exhale pressure to 6 cm. That should still be quite comfortable, and it could prevent the few OA events that you are having.

But will that do anything for your sleep quality? Hard to say. My one thought is that 6 cm of pressure is quite low, and some can feel somewhat starved for air at that setting. It depends on how you feel it, but one other change to consider would be to increase your minimum to 7 cm to see if that feels better and gives you a better sleep. If you do I would also increase the ramp start pressure to 7 cm.

And, as we discussed before it can take a while to get comfortable with a PAP machine. One other minor comfort trick is to turn on the prewarming 10-15 minutes before you go to bed. It is a function on the user menu that you can select. That warms the water in the humidifier and get your more humidity sooner. Do you have a heated hose? That can add some comfort too. The machine can be set to auto humidity control.

Hope that helps some,

The March 20 night looks promising at 14 cm. However the Mar 23 at 8 cm does not look so good. Didn't seem to bring CA down and OA is starting to act up. About all I can suggest is trying 12 cm, 10 cm for a couple of nights each. The acetazolamide is also worth a try after that. I would try it at the pressure that has worked the best by then. I recall we talked about the ASV option already and your doctor was not willing to prescribe it.

Short of doing that, there may be some opportunity to tune your machine to provide better control of the central apnea results at altitude when in the pressure support mode. I am afraid I don't have the experience to do that. In the VAuto and S mode you can set an inspiratory time control (TiControl). In the S mode you can set the rise time. These are fairly complex settings and your best opportunity would be if your sleep clinic provided suggested settings that you could try at altitude. See pages 4-6 in the manual at the link below. These settings affect how and when the pressure switches back and forth between inspiration and expiration. They can help prevent central apnea events if properly tuned.

VAuto Manual

If none of this works, then you probably are best to revisit the AirCurve 10 ASV option with your doctor.