Why have my APIs risen considerably?

I've been using my CPAP machine for about a month now. Initial results were good. APIs below 5. Then I developed a sore on my nose so stopped using the a few days until it healed. I saw my sleep doc who increased the pressure from 13 to 14.6. My OSA is quite severe and the pressure need to get to 17. He sold me a silicone Nasal Mask for the sore which is helping somewhat. However my APIs have now risen - mostly above 10. Does anyone know why this has happened. I have trimmed the silicone nose pad quite a bit as it caused a lot of mask leakage.

Sorry. The APIs I refer to should read AHIs 🙄

What makes you say that your pressure should be 17 cmH2O if your AHI was less than 5 at 13 cmH2O? Perhaps you would be better suited to an intranasal mask if you get a sore on your nose. There could be a number of reasons that increase pressure leads to a higher AHI. What is your leak rate?

According to my sleep clinic my AHIs were 27 when tested 18 months ago. My CPAP machine was originally set at 17 but it was too high for me. Swallowed so much air I thought I would pop. They then turned it down to 13 which worked well but since pushing it up to 14.6 my AHIs rose. How do I know what leak rate is? I have a Resmed Elite S9. Thanks.

I would have thought that if your AHI was below 5 they would leave well enough alone. Perhaps you could ask your doctor to have the pressure put back down to where it was when it was working? To get the leak rate on an S9, you would need to get the machine downloaded, or use 3rd party software like Sleepyhead. It will give you a number in L/min which is an objective measure of how much your mask is leaking.