Sierra

I can't find much detail on how the Luna is different from the ReSmart machines. I kind of think it is mainly in the wireless features and app to report sleep data to a smart device. I see that ResMed and 3B Medical (US arm of the China company) have been in a legal battle over patent infringements. ResMed attempted to ban sales in the US but eventually lost. Now 3B is paying royalties to ResMed, and are continuing sales. There did not seem to be much detail on what specifically was said to be copied or infringed on. But, there must be some similarities between the two machines.

ResMed Dispute

I don't know much about the specifics of Reslex compared to the EPR of ResMed and Flex of Phillips. How they can differ is in how they switch from exhale to inhale. The ResMed senses the patient initiation of a change, probably from flow. The Phillips (Dreamstation) tries to time it. I did my trial after the sleep study with a F&P SleepStyle. I'm sure it was using the timed approach, as at time I felt rushed into taking the next breath, and as a result they turned the setting down for me. I will include a link to an article on how the various systems work, but little information on the 3B Reslex system.

Comparing Expiratory Relief Systems

The thing to keep in mind with this feature is that it is for your comfort only. At least in theory breathing out against less pressure should feel better. But exactly how they do it, may negate the benefits. It depends on the individual. It is something you may get used to, or not.

Just heading out to dinner, and I will give you a more detailed response later. For tonight I would set the auto range at 6 minimum rather than 4 cm. Reslex at 3 is good. 12 cm is fine for max. I think your machine is going to do OK for you. It would be nice to know what the max pressure is during the night, but the 95% number is going to be close, so as long as you know that, you should be fine.

I was curious about your BMC machine as I had not heard of it before, and I did a little research on it. From what I can see it is made in China and the Luna model appears to be the latest and top of the line. The lower end model seems to include the RESmart Auto. I did find some information on the RESmart model in an older study which compared 11 different CPAP models. Here is the link to the study:

All APAPs are not Equivalent

The format of the study report is not exactly easy to read and interpret. But the BMC RESmart machine is designated as the "D2" machine. As a comparison the D8 machine is the more common ResMed S9 Auto. From what I can see in the testing, the BMC responds to obstructive apnea as one would expect, but it does not eliminate obstructive apnea as the ResMed machine does. The BMC responds somewhat to hypopnea, but not well compared to the ResMed. The BMC responds to snoring and in fact seems to be overly aggressive in raising pressure in response to snoring. Most surprising is that the BMC responds to central apnea or clear airway apnea by increasing pressure. That is not good if central apnea is an issue with the user. Pressure would be increased and it wouldn't be doing you any good. I suspect at least this RESmart machine is unable to determine the difference between obstructive and clear airway apnea, and blindly responds to them both in the same way. The reporting of the type of apnea event is likely compromised as well. The ResMed uses pressure and flow oscillation to distinguish between CAs and OAs, and only responds to the OAs. Last the BMC machine seems to over estimate the AHI remaining during treatment, while the ResMed under estimates it. So in your case that would seem to suggest the machine is not under reporting your events, and may if anything be over reporting. Not an explanation for what you are observing.

In my search I stumbled on a YouTube video on your machine which you may have found already. In any case the link is below. It outlines a method of extracting data from your machine if you have a smart phone. That may be very helpful in trying to figure out what is going on. This is the third of a 3 part series. I did not look at the other two, but this one seems good.

BMC Luna G2 Auto Clinical Settings and Icode Data Part 3 of 3

One of the things I saw in the video was that the machine has a sensitivity setting. If you find it is raising pressure too much when in Auto, you could try a lower setting to see if that helps...

In thinking about your situation a bit more I have some further comments for consideration. Your comment that you found the fixed pressure of 4 cm more comfortable than the 4-6 which I presume is a minimum of 4 cm and max of 6 cm in auto mode, is interesting. This would seem to suggest the machine was detecting some issues and was increasing pressure potentially to the maximum 6 cm (which is still very low). I couldn't find much detailed information on your machine, but in general these things respond to more than obstructive apnea. They typically do not respond to clear airway apnea at all as pressure does not help an airway that is already open. However they typically do respond to snoring, flow limitations, and possibly hypopnea. So while you may be getting low AHI, the machine may be detecting these other issues and is increasing pressure to address them. Flow limitations and snoring don't count in the AHI index.

I see that the machine has a exhale pressure relief feature called Reslex. Pressure while you are inhaling helps you breath easier and most find it very comfortable. However pressure when you exhale is what many may find uncomfortable. The Reslex feature reduces pressure during the exhale only. While this feature can reduce treatment effectivness it seems you do not need much. My suggestion for setup in Auto would be to set the Maximum pressure at say 7 cm, and the minimum at 6 cm and turn on the Reslex with a setting of 3. That should provide maximum comfort and a reasonable degree of treatment. But, it sure would be helpful to be able to view or at least see what the maximum pressure it is going to during your sleep. That way you can determine if the maximum pressure needs to be adjusted.

Hope that helps some.

Edit: One more thought. Air leakage may be masking some of your apnea events, if leakage is an issue. The ResMed in some situations does not report apnea if leakage is high.

To put things in a bit of a perspective I was diagnosed with a home sleep study with an AHI of 34 or so. I now treat it with a min-max pressure of 11.2-12.6 cm. I get a very low obstructive index of less than 0.5, but my total AHI including the central apneas is closer to 3.0. My wife was diagnosed in the 70's for AHI, also with a home sleep study, and now uses a min-max pressure of 12-14.6 cm. She has very infrequent central apnea and regularly achieves less than 1.0 for AHI.

That is why I find it a bit strange that you could be diagnosed with an AHI of 46 and only need 4 cm pressure to treat it down to near zero.

I forgot to mention that I think the SenseAwake feature is a good one. It is about the only advantage that the F&P machine has over the ResMed AirSense 10 that I eventually bought. It can be a bit frustrating to wake up in the night with the machine at full pressure and you are trying to go back to sleep. The SenseAwake feature helps you in that respect. About the only way you can do something similar with the ResMed is to reach over and manually turn the machine off for a few seconds. When you turn it back on, it will go back to the ramp start pressure.

I did my trial on the newer F&P SleepStyle machine that had this feature. As I recall the purpose of the SenseAwake is to bring the pressure back to the ramp start pressure when it senses you are awake (perhaps 5 cm in your case). I think it starts to ramp back up again from there, or just sits there if you are not using the ramp, and only increases when the machine detects apnea events or flow limitations. If you are awake, at least in theory you should not have any events, so it should stay at that pressure.

That is very puzzling. I am not at all familiar with that particular machine. I did find a brief clinical manual on line. It sounds like you have figured out how to set it up. I believe you are correct in that this machine is supported by SleepyHead. The F&P SleepStyle I don't believe is supported either. However the sleep specialists should be able to view the data from it. What they should look for is the maximum pressure reached and whether or not there were any apnea events.

Without being able to see the detailed data it is hard to figure out what is going on with your current machine. I guess one possibility is that the machine is not accurately reporting the AHI. Or, the other is that you were misdiagnosed. Perhaps you should ask for a retest at their cost...

I will second what SnuzyQ has said. Tell us all the details on your machine. Download SleepyHead and have a look at your data. I'm suspicious that you must be getting a higher pressure than 4 cm. That is very low, and actually not that comfortable for most people. Here are some instruction on how to use SleepyHead.

Beginners Guide to SleepyHead