SevereApnea Resmed N30 vents blocked: hypercapnea?

[SevereApnea]

First post.
Many thanks to all in this Forum, so much to read.
I have been lurking for a while so as not to appear too ill informed before I post.

I refer to a post by mdmarmd (search P10 vent obstruction etc)
Yesterday, I read this post above with some concern. There are other similar posts about the Resmed Quiet Air bits and pieces.

During my Trial of CPAP I chose the N30 nasal cradle as the most comfortable (read “least problematic”) and chose that for my Titration study. This mask did not, as far as I can remember have the quiet air filtration.

I then bought my own APAP and  N30 cradle, and noticed it DID have the quiet air filter, initially I was pleased with this.  Today I have serious concerns about this.

I am on Day 28 of my N30 own nasal cradle, struggling with leaks etc (more on my personal journey in later posts.) I wash the silicone cushion daily. I wash and dry my ClimateLine hose and mask and headgear once a week, so the N30 cradle and headgear have only been washed 4 times. I wash them in the morning with Morning Fresh (similar to Dawn), dry the hose and mask using the PAP machine blower for ½ hour then hang to dry for the rest of the day.

I use a Foam Neck collar to keep the chin up, and two Alice bands around the mouth to quieten the audible mouth leaks. I try and keep all other variables fairly constant for 3 to 4 days at a time to get an idea of what works and what does not.

Since 18 March 2020 my 95% leak rates range between 6L/min and 41 L/min. Clearly I want to get these down so the PAP can do its thing.
Variable but generally good AHI’s many nights no OSA,  just some CA and hypopneas.

Last Night I did two things.

1. Removed the pillow from the cradle, wrapped lips around the cradle vent, blocked hose attachment and breathed through the vent holes (the ones that house the mesh filter.)
Breathing in felt fine, some resistance as expected.
Breathing out through the mesh was **much** more difficult and made a totally different noise.

2. Just before going to sleep, I tightened the headgear more than I normally do,  used the Run Mask Fit as usual and off to sleep.

This morning woke up at 03:30 feeling really bad: pounding head, sore neck, chest felt stressed, Pulse rate of 60 bpm but heart and rib muscles felt what I can only describe as tired (similar to pre-PAP therapy.)

Stayed awake for a while, read a book until I felt I could sleep again.

Then at 07:40 awoke again to find really good AHI or 0.4 and low 95% leak rate of 4.8 L/min. No dreaded dry mouth!

Happy days, Except That…

I felt even worse! Not felt this bad on PAP therapy, can't even remember feeling that bad prior to PAP. Head felt more puffy, pounding, headache, heart pounding, palpitations etc.
Still have not recovered by 5 PM. Needless to say I can't use this again tonight.

Today I looked at the mask/cradle more closely.
Removed the filter to find the dreaded black spots! I am not a smoker, am meticulous about room cleanliness.

[attachment=21863]

I placed these between my lips to test the flow resistance and found they tasted really salty and soapy. Clearly they are getting blocked, with some residue, my expiratory moisture and or/residual from last week's washing. The tiny spaces between the mesh must be the victim of surface tension and locking in the residue.
Could it be that this is acting like a one way valve and not venting as it should?

Needless to say I will have to make other plans for tonight's therapy.

My Oxygen sats remained good (more on why I am following this in a later post), so I am confident about that.

My question is: is this hypercapnia as discussed by mdmarmd and others?

Have others found the same thing with this Resmed N30 nasal cradle?

[attachment=21862]

[SarcasticDave94]

I don't have the N30 like yours. I have the ResMed F20 AirFit, the silicone full face. My QuietAir elbow did develop the black spots after some use, a month's worth of time or a bit longer as I recall. I would say that at times I felt exhale resistance was higher with QuietAir. I used needle nose pliers to remove the white packing material, and the resistance seemed to disappear. It's vent action and exhalation became louder.

[yankees123]

I use both the p10 and the n30.  I have noticed that using the p10 I can feel more air escaping through the exhalation ports when I am wearing the mask compared with the n30.  I never took it apart and wondering if someone has taken apart the p10 to see of the black dots are also visible.  I would expect it to be the same since the exhaust meshwork looks very similar.

[jaswilliams]

The P10 is just mesh there is no material between the mesh unlike the quiet elbows

[yankees123]

Would it make sense then not to submerge either the N30 or P10 and just use mask wipes to clean?

[SevereApnea]

I took the mesh pieces, soaked them in water only and then used the hairdryer to dry them out thoroughly.
In doing so they seemed to fluff up / expand quite a bit.
Replaced the mesh and just testing it out while awake it does seem the flow is better.
Still too nervous to use this again during sleep at the moment but will likely test this out again over the weekend.

Was at the sleep centre earlier today and discussed this with them. I mentioned that during my trial of CPAP, from memory, the N30 did not come with the mesh. She mentioned that when they order the masks from Resmed they order them either for sale (they come with the mesh) or for trial purposes: then they are not supplied with mesh because of difficulty sterilizing them between users. She did seem to indicate it would not matter if I replaced the mesh or not, apart from being a bit noisier as mentioned by SarcasticDave94. Personally I don't mind the extra noise, but this may be an issue for others.

I wonder if others have noticed any differences when the mesh is removed, either subjectively with respect to sleep quality or AHI, leaks and flow limitations etc.