Chest and Stomach Pain

Does anyone on this forum fully understand how the Resmed S9 Elite model works? I’ve been on CPAP for about two years now. I took a break for a few months earlier this year but my general health deteriorated again. Since I restarted in October I wake up every night after 3 to 5 hours with intense pain and extreme nausea in my chest and abdomen. It takes about an hour of kneading my abdomen to expel air before the pain subsides. I visited the sleep clinic (Cape Town, South Africa) yesterday but after checking the CPAP settings and checking my Mirage Quattro mask they were happy with the equipment and the reading on the SD card, but they didn’t seem to understand the problem of waking up in pain every night. I have thought of visiting an anaesthetist who might be able to advise me but thought I’d put it out to this forum initially. Please I’d appreciate any help I can get. Many thanks 🙏

One other thing I don’t understand. Under Settings the EPR is set at FULL TIME and the EPR Level set at 3. Does this sound right or should it be changed?

It sounds like you may have aerophagia, or air in the stomach. I have never experienced it, but I understand it tends to affect new users of CPAP that are on a higher pressure. What pressure settings do you have? I believe the S9 Elite is a fixed pressure model. Here is a link to an article on aerophagia.

Aerophagia Causes and Resolution

The article may give you some ideas on what to try. One of the suggestions is to use expiratory pressure relief, or EPR to reduce the pressure when you exhale. Your machine is set to do that if it is set to EPR full time and at the maximum 3 cm reduction setting. The problem with EPR is that it also tends to raise the inhale pressure required to control apnea. For example if your pressure setting is 15 cm, each time you exhale it goes down to 12 cm. That makes it easier to exhale, but it also lowers your effective pressure for treating obstructive apnea to 12 cm. But at the same time it subjects you to a 15 cm pressure. It doesn't work this way with everybody, but you could possibly the same treatment with the set pressure at 12 cm and the EPR set to ramp only. In ramp only it makes it more comfortable to go to sleep, but stops the reduction at the end of the ramp. So out of this there are two possibilities for machine settings.

If your AHI is good, is it possible that the machine setting could be reduced, and if necessary could the EPR be set to ramp only. This is a little more difficult to determine with a fixed pressure machine, as about the only way you can find out is by changing the settings and trying it. In an auto machine you could stop the EPR and see if the auto function brings the pressure down by itself. In any case I don't know if you adjust your own machine or not. If not, then this would be something to discuss with your sleep clinic. Also keep in mind that with many people some adjustment time is required, and they get over it.

Thank you Sierra. I can adjust the settings myself. My CPAP was originally set at 18 two years ago and then reduced right down to 10. This aerophagia started a few weeks ago so I thought maybe 10 was too low so increased it to 12 and then to 14 but this made no difference. As my AHI levels are very low I'm going to take it right down to 8 and set it at RAMP ONLY and see if that makes any difference.