Puzzling reduction in effectiveness

I have been using CPAP therapy regularly for about 8 months. Contrary to most newcomers (time taken to get used to it), I was comfortable from Day 1 and got amazing results. I was waking up fresh, alert and daytime lethargy was gone. Even my BP (which was always high in the mornings before therapy) was significantly down (became normal).

However lately (maybe the past month), the effectiveness has reduced by about 50%. Though I don’t think I am snoring (it’s not possible with nasal pillow mask on) have woken up a few times at night with that familiar feeling in my mouth/tongue and not as fresh in the morning as in the first 6-7 months of therapy (and just as I suspected, finding the BP also slightly high).

I am very puzzled – there is no indication of any leak, have not touched the settings and more importantly, the readings (which I check every morning) is exactly how it has always been since the beginning of therapy. AHI of around 1.5 and average pressure of around 10.5. My doubts are more technical – how does the machine calculate the AHI, can it be wrong (how can I have 50% of the symptoms of apnea that I was suffering from earlier with a fantastic AHI of 1.5?). Secondly, even though the average pressure indicated is still the same I suspect that it is failing to increase sufficiently when required. That’s based on feelings - in my mouth itself and also the strong air pressure that the machine was generating earlier (especially in when removed in the middle of the night) seems to be missing – now it just seems to be at the same level.

Would be grateful for any insights, suggestions.

Machine: Philip Respironics System One REMstar Auto
Mask: Philips Respironics Nuance Pro Gel Nasal Pillow
Humidifier: Respironics System One 60 Series Humidifier

If you have selected the correct machine (its a model 560?), it is full data and detailed reports are available.
If you don't have the software, get either Encore of SleepyHead and begin looking at the data. Some folks gain weight after starting CPAP therapy, and if that is your case, it might be possible that you need a small adjustment in your pressures. Only looking at the data will allow you to tell that.

The Respironics algorithm sometimes can be more effective in stopping/treating obstructive and/or hypopnea events if the EPAP pressure is a little higher. In the case of the 560, increasing the bottom of the pressure range is how that is done.

But, data first, then see if the pressure might need to be adjusted. As always, coordinate with your doctor so you two are on the same page. Other, non-apnea things might be going on and you wouldn't want to miss those.

barooah wrote:the strong air pressure that the machine was generating earlier (especially in when removed in the middle of the night) seems to be missing – now it just seems to be at the same level.

Download and use the free Sleepyhead software and you can see a graph of the pressure. No more guessing what the pressure is doing - the graph will show you.

Thanks. This is very helpful. My next step will definitely be to check the data. I do have the Encore Viewer but confess I have not taken the trouble to upload from the SD card and check. Partly because I already know (from checking every morning) that statistics from all these months will be AHI in the range of 1.2 to 1.8 and average pressure something like 10.5. No "large leak". I am ignorant about anything else that can be analyzed with the data.

Regarding model its the Philips Respironics System One REMstar Auto (60 series I think?). Not sure about 560.
Pressure settings are low 7.5 (I don't even use ramp feature since its comfortable enough) and high I think 20 (don't remember clearly since I have never gone to settings myself).

I hope the data throws up something that can be easily addressed in setting. Like I mentioned, I suspect pressure is not ramping up to high levels when required.

Thanks again for your insights and well articulated response.

barooah wrote: I do have the Encore Viewer

Sleepyhead is more popular on this forum - https://sleep.tnet.com/resources/sleepyhead/shorganize

But Encore Viewer is also suitable.