Sierra

Thinking about your dilemma, I came up with a couple of other options to consider.

1. I know it may sound regressive as you have gone from the S7 machine to the AirCurve 10 VAuto, but you might want to consider going to a fixed CPAP pressure mode. The AirCurve 10 can do that. I have actually done that with my AirSense 10 AutoSet and I am getting better results than I was in Auto mode. See this link to another thread for more info.

2. There is a good article in the Blog section of this website on Complex Sleep Apnea. The article mentions the off label use of a drug called acetazolamide to potentially treat central apnea. The intended purpose of the drug is to treat altitude sickness, but the conditions are related. It is something you could discuss with your doctor. If you are only going to high altitude seasonally, perhaps it could only be used when you go to altitude. Again, I am not a medical professional, so I cannot recommend it to you. I just raise it as something you may want to discuss with your doctor.

Ruby, you are obviously a giving person to do all that volunteer work. Well done, and probably without the thanks it really deserves.

On the sleep issues, I have found some help with a Canadian website which was set up by a pharmacist who was concerned about the overuse of sleeping medication, especially in the elderly. His view was that it was contributing to falls and fractures which in turn were compromising the health of seniors and increasing the costs to the healthcare system. He is also a professor at the local university and I suspect this website is likely a grad student undertaking. I found out about it through a CBC new article which gives a little more of the background. In any case here is a link to the site. There is a lot of information there, and it takes a while to get through it all. It certainly helped me with my ability to sleep despite the irritation/aggravation of having to use a CPAP.

SleepWell - It's No Dream

There are two separate issues here. One is in how the machine compensates for altitude, and the second is the issue of lower absolute pressure and as a result lower oxygen in the air on a mass basis. I'll try to keep this simple, but it is actually complicated.

First the machine compensation - The machine simply creates a differential pressure between the atmospheric pressure of the day and location. In other words it supplies 4 cm to 20 cm for example above atmospheric. The machine measures this differential pressure and controls to it without any compensation required. There is a BUT though. The machine measures pressure in the machine not the mask. It only tries to estimate pressure in the mask. As you go higher in elevation the air becomes thinner and the pressure drop in the hose and mask increases. So you are getting a lower pressure than the machine thinks it is supplying. That S7 machine from what I can see probably did not compensate for that error. The AirCurve machine should be compensating. I believe it does this by using a barometric pressure device that measures absolute pressure - which goes down as you increase elevation. The machine uses that pressure to compensate for the increased pressure drop in the hose and mask, and if the ResMed engineers have done their job properly, the machine increases pressure to compensate for the increased pressure drop in the hose. On machines without compensation you had to do this manually. Bottom line is that your machine should be doing this for you, and it should not be the source of your problems.

Now the thin air issue - While the machine is keeping the relative pressure in the mask the same, the absolute pressure is going down. The relative pressure is what keeps your airway open, so it should do just as good a job at elevation of avoiding obstructive apnea. However, the absolute pressure is going down (air is thinner), so the oxygen being delivered goes down. In most people up to 7,000 feet or so, that is not a problem. Your body adjusts breathing and all is good. But, if someone is susceptible to central apnea, which is really a control system problem, it can upset the apple cart. It is like a car on cruise control that keeps over correcting for going to fast and too slow. The speed just hunts up and down and is not stable. Same with breathing except when it goes down or even stops you have an apnea event or hypopnea event. My guess is that is what your issue is.

Guessing a bit here, but usually what this comes down to is that pressure in the machine may be causing the central apnea, and it may need to be lowered. The problem is that lowering pressure can create more obstructive apnea. What this means is that with your current machine the compromise setting of pressure is likely going to be different at elevation than at lower levels. But, if you can get a good compromise setting at altitude, it most likely will also work at lower level. If not, then you would have to change the settings so you use two different setups. I presume you are going to Mexico(?) seasonally? If so, that would not be a big deal.

You can do what you are suggesting and get another sleep study done at elevation. However, what I would suggest is that you download a free software program called SleepyHead and use it to view your data which should be all on the SD card in your machine since the day you started using it. From that, you may be able to determine what settings are best. If you post a typical daily detail report for the two elevations, I would give you my comments. I am not a medical professional, but I also suffer from mixed apnea, and can comment from a user perspective. It is not the easiest type to apnea to deal with. At the end of the day, if you are unable to get successful treatment (AHI<5) by optimizing the settings of your AirCurve 10 VAuto, there is another machine, which could work much better called the AirCurve 10 ASV. It is expensive and some heart function tests have to be done before going on it. Something to discuss with a sleep doctor, and a cardiologist. Depending on what part of Canada you are from, that can be difficult... This all said, there may be options to set up your existing VAuto machine better. I would investigate those with SleepyHead first.

If you are using a BiPAP that complicates things a bit. It would be really helpful to post a SleepyHead chart so I can see what the machine is actually doing. SleepyHead will also report all the settings.

That number for hours sounds very low. Is the Machine Hours higher than the blower hours? My wife's ResMed S9 is about 4 years old and it has 12,700 Run Hours. That works out to about 8.5 hours per night, which is about right for her.

I understand your concerns. I initially rejected mouth taping too, as did my wife. But, we are now both using it. There are other options to allow use of a nasal mask. One is to use a chin strap. I have about 4 of them including a home made one from a tensor bandage. Surprisingly one of the better ones I tried was from Princess Auto. They had them on a special two for about $7 or so. It helped quite a bit. I now use one called the BreatheWear Halo, which I got from SleepYeti in Calgary for $25. It is probably the best one so far.

I hesitate to make any suggestions for a full face mask. I have tried the Mirage Quattro and hated it. I then tried the AirFit F20 which is supposed to be an improvement on the F10 you have. I couldn't make it seal and be comfortable and gave up on it, and went back to the nasal pillow P10 mask and the chin strap.

There are some interesting new masks out there including the DreamWear system mask. The headgear and frame can be fitted with a full face, nasal, or nasal pillow insert without replacing the whole mask. I have a friend that uses one, and he likes it. But, I have no other experience with it.

Masks are difficult. I certainly have not found the ultimate one yet. I have mask #6, a Swift FX in the mail to me now. Perhaps it will be the perfect one!!

Thank you for the kind words. And you do know that you can get masks in pink too, if you want to stay well coordinated!

Mouth breathing has its own set of issues, and is not ideal with or without a CPAP. If you do go down the CPAP route, I would suggest trying a nasal pillow mask first, despite the fact you may be steered away from it due to mouth breathing. If necessary you can mouth tape to stop the mouth breathing. It is not nearly as bad as it first sounds, and in my opinion a better solution than using using a full face mask. For sure a full face mask prevents air loss out of your mouth, but it does not stop mouth breathing. A video to watch if you are interested.

How to Mouth Tape for a Better Sleep

Here is an article that seems to be fairly current (2017) that compares the two approaches to normalizing apnea.

An update on mandibular advancement devices

It may be a much deeper dive than you want to take. What I gathered from it is that neither CPAP or MAD are a silver bullet to solve apnea. In basic obstructive apnea especially in the moderate range that you are in (AHI 19) a very high reduction of AHI is almost certainly to be achieved by CPAP, BUT, and it is a big BUT, that is only if you use the CPAP. The MAD on the other hand is likely to have a higher compliance rate, but less likely to normalize AHI fully (<5).

So on one hand you have a very good solution (CPAP) but say for example only a 50% chance of sticking with it. On the other hand you have a solution that may only achieve a 50% reduction, but you are likely to use it. Kind of hard to compare on an apples to apples basis, but this article attempts to do it, and out of it rationalize that MAD is just as good as CPAP on a statistical basis. That to me is a little misleading. At the end of the day you are going to use a CPAP or not use a CPAP. So it is really an all or nothing solution. The MAD is a near certain partial solution, unless you have a personal issue that makes it not suitable as your ENT has suggested. You kind of have to pick your poison. My thoughts are that the reasonable approach is to try the CPAP first. If it works and you like it, then you have the best solution. If the CPAP does not work, or you just can't tolerate it, then the MAD is certainly worth trying. A partial solution is better than no solution. In short I think it is a sequential decision not a one or the other decision.

That all said, I know I didn't answer your direct question. However, there are a couple of dentists that specialize in sleep appliances that check in here and can give you a much better answer to your real question which was on how you can determine you are suitable for a MAD.

I use the ResMed AirFit P10 nasal pillow mask and have congestion issues. That said I do not find it really causes me a problem if I get my nose clear before I go to bed. I occasionally use an Otrivin type spray in one nostril, but try not to use it in both and avoid using it daily. Apparently you can get a rebound effect if it is used too often. I also use tape over my mouth to ensure I breathe through my nose and no air escapes out of my mouth.

If you cannot get AHI under 5 and central apnea (clear airway) remain an issue, there is another option to explore. That is an ASV machine like the ResMed AirCurve 10 ASV machine. It is expensive, and not for everyone. You need to undergo a special heart function test before they will prescribe it. But for those that suffer from central apnea that cannot be reduced any other way, it can work. Some glossy manufacturer info on the machine. It is something you would want to discuss in full detail with a qualified sleep doctor and cardiologist before going down that road.