EVIDENCE OF AIRFIT P10 VENT OBSTRUCTION CAUSING HYPERCAPNIA

[Sleeprider]

It's interesting you spoke with Dr. Thomas. He was the developer of Enhanced Expiratory Rebreathing Space (EERS) that I mentioned earlier, and his research is the basis for our EERS wiki article. Plugging the vent and using a Whisper exhale vent with a designed dead-space for CO2 is the basis for EERS.

[mdmarmd]

Sleeprider,

I kinda suspected this might refer to the same thing you mentioned since he used it in studying central apnea patients.  I just had too much going on to bother looking it up.

[ghce]

they were really black with dust!

ghce,

i curious to know the conditions that led to your vents being so dirty?

Usually, they just begin to look a little grey/brown to the naked eye compared to new P10 vents.

Did you use it a really long time? It sounds like you've used them at least for a years time.

Do you change your CPAP filter with some regularity?

Do you live in a very dusty environment?

Anyway, just curious to know what would lead to such visually prominent dust deposits.

I took some macro photos prior to cleaning them, will try and upload them later.

The P10 mask I am using is just shy of 1 year old in usage, I cleaned it about 5 months ago though it didnt look quite as dirty as this time.

The CPAP machine sits in the floor which may contribute to the dirt / dust build up. My house gets vacuumed several times a week and the bedroom windows are closed 99.99% of the time so there should be less blown in dust.

I only run the machine humidity on a setting of 2 and dont use the heater, the tube is always free from condensation and never looks in any way dirty.

The inlet filter is still the origional one so likewise just shy of a year old though I have blown it out with my 110 PSI compressor a couple of times in the past year.

[mdmarmd]

ghce,

I look forward to seeing your pictures.

I always use a filter and change them fairly frequently since they are cheap, and probably the best way to protect your vents, as well as the blower in your CPAP.

Once, for a short period I used my CPAP without the filter because I needed to accelerate making "dirty vents" so I could try the ultrasonic cleaner since I'd cleaned all my P10s already.  When I looked at it under magnification to do the "before" pictures, it was clear that the CPAP filter was not there because there were minute, black fibers scattered about.  These would have never made it past the CPAP filter. They clearly were in the room air and were blown into the vents.  

Some have conjectured that the dirt comes from our exhaled breath, but I doubt this is much of a contributer. Particulate matter is efficiently trapped by the mucous membranes and cillia of our airways. However, if you cough or sneeze, the velocity of the air accelerates enough to aerosolize secrections and bacterial matter (how TB spreads). If you have COPD and bronchitis you may hack up a lot more solid material. But otherwise, I think most of what's trapped in the vents has entered through the intake port of the CPAP.

[ghce]

Left and right exterior and one interior

[ghce]

ghce,



I always use a filter and change them fairly frequently since they are cheap, and probably the best way to protect your vents, as well as the blower in your CPAP.

I did notice that there was a mention of hypoallegenic filters being available which sounds like a good idea, I dont like the look of the supplied origional filters ( its a very open weave!) but I guess the better the filter the more restrictive to airflow it will be and that would make hard work for the machine pump and flow volumes.

[mdmarmd]

Wow!

Those really are dirty. I've never gotten mine that bad.

I think you are fortunate that you have not experienced frank condensation, otherwise I can't imagine that your vents would not be fully obstructed.  

Would have liked to measure your CO2 then...or maybe not.

It looks to me like you might even be growing stuff on your side of your precleaned vents.  If that's the case, I think I'd replace them, because there might be enough bio material on the plastic to culture something up again.



BTW you mentioned:  I guess the better the filter the more restrictive to airflow it will be and that would make hard work for the machine pump and flow volumes.

I don't really think it's a problem because I don't think the velocity of the air flow is so high that the filter creates that big a drag on the system (unless you let it get too impregnated with dust).  The bigger load is from the pressure differential downstream from the CPAP, at least when the vents are open. When the vents obstruct, the CPAP faces maximum load as it tries to push air forward but can't.  

I have put two regular filters on instead of just one, once I realized how important it was to keep the vents dust free. I don't think it sounded like tha CPAP was taxed by doing so.

[ghce]

During the winter I did have problems with rainout in the tube and that led me to do the first mask clean though I hadnt been particularly aware of the reduced mask venting as that concept had not filtered into my brain until you starting this thread. Venting must have been close to zero, it  was almost zero prior to cleaning it 3 days ago!

I most certainly would have liked to know what the CO2 levels were like as this last year I had been noting like you that I was having ( still am) memory problems which I have never had in the past prior to starting CPAP even with my AHI being 48 prior to treatment. 

I had always in the past  believed that CO rather than CO2 was the one to avoid and that we could tolerate much higher levels of CO2 with out issue other than an increased respiration rate. This thread has given me pause for thought.

Good to know that you can double up on the filters though it would be nice to find a finer filter than the OEM one.

[Hydrangea]

I have not read past the first couple posts and the last couple posts in this thread (thus far), but I'd like to share my experience in order to add to the discussion.

I switched to the P10 and was a mega-fan due to the simple interface. I took to it with ease. After about a year, I'd wake up around 5-6am with a slack jaw and mouth wide open allowing all air to escape. I concluded my body must no longer be willing to keep my mouth closed in the early AM hours, so I must need to switch to a FFM. (And I've been using a FFM since then.)

I recently switched DMEs, and encountered fantastic RTs and support staff. I mentioned my P10 saga, and was immediately asked how often I cleaned my P10s. I admitted I had become quite complacent and didn't ever clean it besides switching out the actual pillow every 4 weeks in order to maintain a good seal. The RT said that's my problem, and she specifically pointed out "The same slime that forms in your humidifier tank also forms in your mask." Well that grossed me out, and was an effective comparison, because my humidifier tank sure does get slimy after just a couple of days (if I'm not changing the water daily).

What struck me was the RT wasn't at all surprised by what I'd said, and she acted like it was a totally normal problem that people experience with the P10, but that regular and thorough cleaning could prevent it.

Honestly, the reason why I so very rarely cleaned the P10 was because of all of the stories I'd heard here about the vents getting clogged with moisture from having been recently cleaned.

So maybe it's imperative to clean the mask vents often (weekly??), and to have a 2nd set on hand to use the night of the cleaning while the just-cleanded one dries thoroughly?

P.S. The vents on my P10 look clear (not at all gray). I also change my CPAP filters every few weeks.

[SnoringInOregon]

I once again want to thank Doug aka mdmarmd for investigating this issue.

As I mentioned on a previous post a few weeks ago
http://www.apneaboard.com/forums/Thread-...#pid285024
I also had this problem. Fortunately my problem was clearly due to water condensation, not dirt. I was able to solve it by dialing back the humidity setting on my machine.

Having graphs of CO2 quantifies the problem. But that's not practical for most of us. But we all should be using SleepyHead. So I want to emphasize that using SleepyHead will show you how well air is flowing thru your mask, which is what you really want to know.

Unfortunately SleepyHead terminology (maybe because of Philips Respironics terminology?) uses phrases like "Leak Rate" and "Total Leaks" in its graphs. That can be confusing.

At least for SleepyHead v1.0.0-beta-2, when used with the Philips Respironics DreamStation, the line labelled "Total Leaks" in the "Leak Rate" graph is the one to look at. Total Leaks really means "the total amount of airflow coming out of the DreamStation to your mask in liters per minute". It's not a "leak". It's just regular, normal, airflow.

On the night I had my problem with my P10, look at the picture attached for the values of my Total Leak line. At the minimum point, my total airflow falls from about 24 liters per minute to about 2 liters per minute. That's bad. That's very bad. I'm sure that if I had a CO2 sensor I would have seen a corresponding buildup of CO2.

So, long story short, look at your total airflow. It is a good indication of whether or not your mask vents are working properly.


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