Thanks for your efforts, HoseCrusher. They are appreciated.
To quote Carl Sagan, "Extraordinary claims require extraordinary evidence". The experimentation described below is interesting, but I think fails to provide the extraordinary evidence required to justify the conclusions that have been made. With this, I've made a few comments, below on where I find the methodology to be weak and unconvincing. I've also tried to point out what might be done to make it stronger.
HoseCrusher wrote:The methodology is very simple.
Wash hose, mask, and humidifier tank.
Rinse with distilled water to make sure no residue is left.
At this point, you need to measure the final rinse water as a test of cleanliness. This step needs to be repeated every time you clean your system for the next experimental run.
HoseCrusher wrote:Fill humidifier tank with distilled water that you have measured the purity of.
Make sure the xPAP machine is on the floor and the hose and mask are elevated above it in elevation. My set up has an elevation change of 24".
Turn the machine on and adjust the air flow to match the air flow of your mask. This involves blocking the air to your nose and making sure the vent is clear.
How did you block the "air to your nose"? Are you certain that the method used did not affect the quality of the condensate? e.g. by addition of salt from sweat?
How long did you run the system?
HoseCrusher wrote:Condense the air flow from the mask, and measure the condensate.
How did you condense the air flow from the mask? Again, are you certain that the method used did not affect the quality of the condensate?
Did you run the experiment more than once and were your results repeatable?
What instrumentation were you using? Did you do a calibration on it before and afterwards by measuring a control solution and did those numbers match? If they didn't, then any of the other measurements cannot be trusted. Calibration with a control solution is an essential element of any quality experimentation.
When using your mask in this experiment, was it a new mask or one that you had worn before? Did you remove the headgear to ensure that there was no way for it to contaminate the experiment with salt from sweat (headgear likely cannot be adequately cleaned for an experiment such as this one).
HoseCrusher wrote:Compare the purity of the distilled water you started with to the condensate you ended up with. Since you started with distilled water, if everything is clean you would expect to end up with condensate that has the same value as the distilled water you started out with. I came very close to the same values.
"very close". But not the same. If you had no salt in your humidifier, what was the source of the salt that caused you to come "very close", but not match the salt concentration in your distilled water? Did you also measure the final salt concentration in your humidifier? It too should match that of the starting solution? And did you use controls to calibrate your measuring equipment before and after each measurement? This is needed to ensure that you are measuring what you think you are measuring and to calibrate the experiment.
HoseCrusher wrote:Now that you are sure everything is clean, add some salt to the humidifier tank water and repeat the process.
if this is a pure distillation process, the condensate should match what you had when you ran distilled water without salt.
In my test I found salt in the condensate. This indicates that some water drops are making it up the hose and through the mask.
My recollection was that you ran your humidifier with salt, first, and later did the run with a "clean" system. Also that you ran no controls to ensure that your system was clean of the salt from the earlier runs. It's also not clear if the headgear is on your mask when you run the experiment, thereby acting as an uncontrolled source of salt (from sweat).
It might be useful to rinse your hose with distilled water and measure it to see if there is any salt in there, too. That sort of control will help determine if the salt is moving through the hose and not just appearing in the distillate water through some other experimental error.
A mechanism for transport of the salt from humidifier to your distillate water also is needed. It has been suggested elsewhere that this is through aerosolisation in the humidifier tank. If this is the case, I would expect that the amount of aerosolisation and resultant salt in your distillate should be directly proportional to the airflow through the humidifier tank. This can be tested in the experiment by carrying out additional runs with varying air flow rates. It would be best to quantify these rates with suitable instrumentation for each run (not sure how you might do this). There should be a lower cut off below which there is no aerosolisation.
Without a plausible explanation of the source of salt that you are measuring in your distillate, all we can really conclude is that the source of salt is unknown, but
suspected to be from the salted humidifier. If you can experimentally demonstrate that there is a link between quantity of salt in the distillate to the air flow rate through the humidifier, I think it would be reasonable to conclude that aerosolisation is occurring in your humidifier tank.
Finally, a complete experiment would seek to make predictions about the amount of salt that can be moved from humidifier to mask for various air flow rates and salt concentrations. This would include assessment of various types of salts (not just NaCl - table salt). Admittedly, this may be beyond the scope of a home experimenter.
In all, I think the experiments have been interesting, and you've advanced the discussion about possible movement of contaminants from from humidifier to mask. However, more work is needed to provide confidence in the results.
HoseCrusher wrote:I decided to take advantage of this "feature." I keep my tank clean and add a little salt to the humidifier water. It's kind of like sleeping on the beach...
I will add that I have had this discussion with my RT and a couple of Pulmonologists. They reported back that a few of their patients were having difficulty with xPAP therapy due to congestion. When they insisted on weekly cleaning of the humidifier tank, the problem congestion disappeared. I don't think they got as far as adding salt, but I was told it wouldn't harm me in any way.
I think it all comes down to what your immune system can bare. You can be pro-active and have a regular cleaning schedule, or you can just let things go and exercise your immune system. If you get sick, have congestion, or have sinus issues, you may want to stack the deck in your favor and clean things a little more often. If you never have a problem, don't worry about it and rejoice in the fact that you have a strong immune system.
