There are several factors involved here. First, it used to be that starting my CPAP machine would cause my nostrils to inflate a little but resist the expansion, and then a couple of minutes later they would gradually relax to allow a greater expansion. However I have recently noticed that my nostrils no longer resist the initial application of pressure and seem to go immediately to the fully expanded state.
Secondly, my nasal pillows seem to move further into my nostrils than they used to, to the point that they sometimes cause discomfort or soreness. Several weeks ago I contracted a nasal infection which may be related.
Third, I woke up last night in the middle of the night with a feeling that my mask was suffocating me. My attempts to deliberately breathe more deeply were entirely unsuccessful. Eventually I realized that my left nostril was either blocked or severely restricted and I would have to take off my mask. I then discovered that my left nasal pillow had moved so far up inside my nostril that it was causing the blockage. It took a surprising amount of effort to remove it.
I have never experienced anything like this before. The possible causes that occur to me include: something wrong with the nasal pillows or the CPAP machine; an unusual force acting on the pillows mask while I was sleeping; or nostrils that have gradually become enlarged to the point that a pillow can move up inside.
My CPAP pressure settings are unchanged from 6 months ago, and so that is not the issue.
The fact that last night I was able to put the same pillows mask back on, restart my machine, breathe normally and get some more sleep seems to rule out an equipment defect. The only source I could find of a possible unusual force acting on the pillows mask was a minor torsional twist that I observed in the mask tubing and corrected before going back to sleep. And so I am left wondering about the possibility of my nostrils gradually stretching under pressure.
Has anyone else experienced something similar?