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The best source of answers to your questions is the data from your sleep studies. See if you can get a hold of it yourself. It can tell you what is going on while you're sleeping and if your treatment is working.
Get those leg movements sorted and see how you go. That is certainly enough to make you tired. Like the man said.
The reason that all apnoeas and hypopnoeas are weighted equally is that, while the duration and degree of oxygen desaturation can be of significance, most of the damage is caused by the arousal process which is the same for all of them. Also, whether an events is a an apnoea or a hypopnoea has little bearing on its duration or degree of desaturation. The difference between the an apnoea and a hypopnoea is very arbitrary. To be an apnoea there must be a 90% or greater reduction in respiratory air flow compared to baseline. If the reduction is 89% it's a hypopnoea. In either case you don't get enough air and it's causing damage to your body. AHI is not a perfect measure, and in the realm of medicine very few measures are perfect, but it is a pretty reasonable indication.
The other thing, of course, is that AHI should not be considered in isolation, but rather as part of a full suite of data from a properly performed, monitored and scored sleep study. It is very easy for people (including doctors) to fall into the trap of just looking at the AHI and nothing else. Care and should be taken by all sleep professionals to take each patient's individual situation into account. An AHI reported by a CPAP machine is far more reliable when a patient has had sleep study to assess the nuances of their particular situation and their response to treatment. We can be far more confident a machine returning a low AHI is providing effective treatment when we know what duration and severity of events are at different stages of sleep and how they responded to CPAP. In most cases we can be pretty confident that if the machine-reported AHI is low then a patient's oxygen levels are high and stable when we've already seen that this is the case in a titration study. Conversely, if we know that someone still has low oxygen levels, even though their respiration is stable, then we know that the AHI is not telling us the full story.
AHI is a useful tool, and like all tool it only works when used correctly. There is no substitute for good quality, conscientious, compassionate medical care.
The AHI reported by your machine is designed to err on the side of overestimation, so it may be a little higher than that from a sleep study. This is not unusual amongst medical devices, as a false positive, resulting in further investigation and eventually finding out that everything is OK, is more desirable than completely missing a problem altogether. Also, there are various things which can trick the machine and lead to a much higher AHI being reported than is actually the case (Periodic Limb Movement Disorder is a classic case in point). So, the AHI from your machine can often be a little higher, and sometimes a lot higher, than you would get from a full sleep study, but it will almost never be lower. SO when you get nice low numbers like an AHI of 1.5 you can be pretty confident that you are doing very well.
Keep an eye on that P10. The P10 is notorious for the straps stretching and requiring frequent replacement.
There doesn't even need to be a total apnoea for it to be Cheyne-Stokes. I agree that the second sample has a fairly appropriate shape but, as I mentioned above, Cheyne-Stokes cannot be properly diagnosed without a CO2 level as well. When data from a machine reports Cheyne-Stokes it is really just an indication, not incontrovertible fact. It's a bit naughty of them to claim to be able to diagnose something which they really can't. All data from a download is best interpreted in the light of medical history, other downloaded data, recorded sleep studies etc.
Also, the ResMed Clinician's manual isn't exactly the best source for detailed technical info on scoring of sleep. There are international standards for how these things are assessed and it's a bit more complicated that the RedMed manual suggests.
When a machine reports Cheyne-Stokes breathing it's just guessing. It really doesn't know. It is quite common to see some Cheyne-Stokes on a download but it is almost always not real Cheyne-Stokes. That looks like series of post-arousal events. Cheyne-Stokes doesn't start and stop that quickly.
The DreamWear full face is similar to the Amara View but it sits a little differently under the nose and presses on the upper jaw less. It may be worth a look. It does have magnetic clips though, so if you have a pace maker, implanted defibrillator, cochlear implant or any other implanted electrical device you can't use it because the magnetic clips can stuff the device up.
I use almost entirely ResMed, Respironics and Fisher & Paykel machines, which together make up over 90% of the global market (last I heard anyway), although I do occasionally come across one of the other companies. Certainly with those 3 brands their standard fixed pressure CPAPs record just as much data as their auto counterparts. In fact I have not come across an auto which records more data than its fixed pressure equivalent, although some companies have released dumbed down versions of their machines in the past which record less data. Also, some of the lesser brands don't record as much, so if you're not getting one of the big 3 it's looking into their data reporting capability. However, it's not necessary to get an auto CPAP just to get the best data recording.
There's a bit more to recognising Cheyne-Stokes respiration than just the characteristic wax/wane pattern. While that is part of it, many other forms of central apnoea can have they same wax/wane patters as happens in Cheyne-Stokes. To be true Cheyne-Stokes it must also be accompanied by a low carbon dioxide levels. This is part of the mechanism of Cheyne-Stokes. It is a rise in your CO2 level, rather than a decrease in your O2 level, that tells you when to breathe, however, your body can only properly monitor your CO2 levels within a certain range. If it gets too high then you body can no longer see the very small increase and decrease which triggers your breathing mechanism, so it then switches to O2 drive meaning that it is your O2 levels that triggers your breathing response. The problem with this is that your body is much worse at monitoring its O2 levels than CO2, so your breathing is much less stable on O2 drive. If your CO2 levels go too low, as in Cheyne-Stokes, then your body just thinks "cool, I don't need to breathe" and so it stops. after a while of not breathing your CO2 will come up again and restart your breathing mechanism, which will send it too low again and repeat the cycle. This is what causes the wax/wane pattern of Cheyne-Stokes breathing. The difference is very important because to fix someone with elevated CO2 levels you need to help them breathe more, thus getting more O2 in and blowing more CO2 out and pushing CO2 levels down. If you do this to someone with Cheyne-Stokes breathing you will send their already low CO2 even lower and only make things worse.
Appropriate treatment for any form of respiratory failure is not really about which machine is used so much as it is about how it is set. Some different machines do have different settings available, but unless they are set in a manner appropriate to the condition of the patient, they will be useless.
Cheyne-Stokes is just one form of central apnoea and far less common than others. Each requires its own tailored response.
I hope that is useful for you.
