Sierra

Franco, your good results using EPR motivated me to try it again for myself. I went through a very long trial and error process to end up with what I have been using for a couple of years now -- 11 cm fixed pressure in manual CPAP mode with EPR on Ramp Only. For last night I changed that to 13 cm (to compensate some for the EPR reduction) and turned EPR back to full time. I had intended to try this a long time ago but had never gotten around to it after I settled on the fixed pressure mode. Your results prompted me to try it.

In any case I got about the best results I have ever had with this change -- API of 0.4. 95% Flow Limitation was 0.01. Almost zero. This is one night only and may have been a fluke, but I will leave it there to see. My biggest issue has been hypopnea events and not so much OA events. For the night I got zero hypopnea events and one each of the CA and OA. Kind of amazing. Will have to see if it is repeatable. I did not notice the extra pressure during sleep and my leak rate was quite acceptable, although not zero.

I agree. EPR seems to be helping you. First time I have seen it demonstrated to be a benefit. I learned something.

First to be clear, I am not a doctor, just a mechanical engineer. I know more about machines than bodies. ResMed does not say much about flow limitations but the machine certainly does respond to it in Auto mode by increasing pressure. I think it may be the first warning of an impending hypopnea event or even obstructive apnea event. My wife also uses a CPAP and her 95% Flow Limitation also seems to be up in the 0.28 range, like yours are with no EPR. My typical 95% Flow Limitation is 0.09. She also suffers from Snore more than I do. I was diagnosed at about 37 for API. She was diagnosed at more like 83. So perhaps it is an overall indication of sensitivity to apnea. I have found that I can reduce the flow limitation and snore for her with more pressure. However she dislikes the additional pressure and I cut it back. Her machine is set with a minimum of 13.6 cm and 14.4 cm Max, and no full time EPR.

But we are all kind of different. My wife almost always is under 1 for AHI. I am happy to be under 2. She gets no CA events, and for me after H events CA are the most common.

All considered, with your EPR on Full Time I think your machine is set up well. Allowing pressure to go above 16 cm may reduce your Flow Limitation numbers, but like my wife, possibly not your comfort level. Some clinics set the maximum pressure at the 20 cm default and let the machine do what it wants. It is an option, but you will deal with the potentially increased frequency of mask leaks. On the other hand I cannot let the machine keep increasing pressure as it causes lots of CA events. That is the main reason I switched my AirSense 10 from Auto to fixed pressure CPAP mode.

Well, even though the AHI is better the pressure is certainly not lower. I don't think you are gaining anything with the EPR set to Ramp Only. I think I would switch it back to Full Time. The 95% Flow Limitation number seems to have about doubled from when you had the EPR full time. It has gone up from about 0.12 to 0.28. Your OA events have gone to zero, but I think Flow Limitations are driving the pressure up.

If you ever have issues not being able to control the Flow Limitation issue, you may be a candidate for a BiLevel machine instead of the standard APAP. EPR on an APAP is limited to 3 cm differential between inhale and exhale pressure. A BiLevel can go much higher, and the maximum pressure can go up to 25 cm instead of the 20 cm limit on an APAP. But, for now I think you are doing fine with an APAP.

It may be worth trying it another night just to confirm, but from what I see you may be one of the few that do not benefit from having EPR off during sleep. It looks like the pressure is being driven up by the Flow Limitation rather than the obstructive events. The EPR may be helping to reduce the Flow Limitations and actually results in a lower pressure. If pressures do not come down on the second night, it would be best to go back to EPR Type of Full Time. That is the way it goes with CPAP treatment. It is always a bit of trial and error.

I will start a new full width post because when you keep replying to post after post they get kind of narrow on the page! You said:

"Given the fact that with the increased pressure my AHI's are so dramatically low, with practically no OA's and very few, short Hypoapneas, what perceived benefits should I expect from using the Ramp-only feature? Better, more refreshed?"

I can't predict how refreshed you will feel, but what you quite likely will see is that the actual pressure used in auto over the night will go down. This should feel more comfortable, and make the mask less likely to leak. That also could make you feel more comfortable. I wouldn't expect your AHI or apnea events to get better or worse.

On the travel issue, before COVID, we travelled a lot. Airlines let you take a CPAP as an extra carry on piece of luggage with no charge. They will want you to take the CPAP out of the case, but other than that you should sail through security. Getting water for the humidifier can be an issue. For periods of up to two weeks we just use tap water. You probably have to use some extra vinegar to clean out the reservoir after you get back, but overall no harm done. If you look around the airport in the boarding lounge you may be surprised how many people have a CPAP. The advantage of the AirSense 10 is that it packs up quite small. It can accept 230 volts or 110, but you may need an adaptor to fit the wall socket depending on the country. We would not consider travelling without them. My wife and I both use a CPAP.

Franco, I reread my instructions and I see I made a mistake on the name of the option. I said Ramp Type instead of EPR Type. Sorry for misleading you. I corrected the post so it says EPR Type.

See page 16 of this manual. It shows the options under the Comfort section:

AirSense 10 Clinical Manual

From what you are describing, I think you have selected the Ramp Time option instead of the EPR Type. From what I see of your Oscar reports you have Ramp Time set on Auto -- which is good. Go further down to EPR Type. There should only be two options Full Time (which is where your machine is) and Ramp Only. Choose Ramp Only.

From the Manual:

This may be more detail than you really want, but it may help you understand why EPR which is a pressure reduction on the exhale part of the breathing cycle, can cause apnea events. See this zoomed in Daily Report example of a OA event. This was very shortly after I started CPAP treatment (three years ago) and was not getting very good results. At the time my machine was set up with a Minimum Pressure of 10.4, and Maximum of 15 cm. EPR was set to Full Time and at 3 cm.

If you look carefully at this OA event it basically starts where the green vertical cursor line is just before 1:03:40 for time. The Flow rate should have gone above zero in into an inhale cycle at that point, but it does not. The pressure due to the EPR is at 9.5 cm, instead of the higher 12.5 that one would expect it to be at. That is the main learning point. The event which is a collapse of the airway started at the lower exhale pressure. The higher inhale pressure did not prevent it because that machine had not increased it at that point. In fact it did not increase the pressure until just after the machine flagged it as an OA event.

I hope this shows why the EPR feature can have negative impacts on how the CPAP controls apnea events. I now use a much lower fixed 11 cm of pressure and no EPR after the ramp ends and have much fewer events than when I was using EPR. If you have any questions, just ask.

If you want to read a bit more about the issue of using the EPR feature see the link below to an older thread. "sleeptech" was a regular participant here a few years ago. He works as a sleep technician setting up CPAP machines in Australia. I can't say I agree 100% with what he says is an issue, but for sure he is right on the fact it can raise the needed pressure to treat the apnea in most users. The feature is sold as a comfort option, but it has a price of needing more pressure. Not everyone responds the same, but you will find out fairly quickly how well it works for you.

https://myapnea.org/forum/not-understand-epr-setting/1#comment-5056

Here are the steps to change the EPR to Ramp Only:

1. Press the Round button to light up the menu screen
2. Press and hold the Round button and the rectangular Home button at the same time for 5 seconds to display the Clinical Menu screen
3. With the Clinical Menu option highlighted press the Round button to select it
4. Rotate the Round button to highlight the EPR Type option
5. Press the Round button to select it
6. Rotate the Round button to select Ramp Only
7. This will bring you back to the Clinical Menu options
8. Press the rectangular Home button once
9. Rotate the Round button to highlight the Exit Clinical Menu option
10. Press the Round button. You are done!

That is it. It sounds more complicated than it really is. That is the only change you need to make. The pressure does not have to be changed as the machine should automatically use less pressure. You should try it for a few nights to see what difference it makes to pressure. With Oscar you should see the pressure graph change so the red and green lines track over each other after the initial "ramp" at 10 cm ends. You should also see on the left section for Machine Settings show the EPR as Ramp Only.

Minute ventilation is disturbed by apnea events. It can also be disturbed by central apnea breathing issues like CSR. Sometimes you will see minute ventilation cycling before a central event occurs. It is a good overall measure that breathing is stable.

Any questions, just ask.

Are the Canadians back playing again? I was looking forward to the three games this week with Edmonton (where I am from), but they all got cancelled due to COVID...