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An interesting development...

The subject of bacteria from the humidifier being transported in the air stream came up earlier in this discussion. There is on paper on this and I have been in contact with the doctor that wrote it. I told him about my experience with salt in the water of the humidifier and he put me into contact with the editor of the Southern Medical Journal who asked me to write a letter to the editor.

Here is the letter I submitted.

"With much interest I read the article by Dr. Raymond about the possible contamination of CPAP air via contaminated water in the CPAP humidifier tank. Evaporation should not be able to carry contaminants into the airflow, however, Dr. Raymond’s case seemed to indicate otherwise.

As a xPAP user myself, I searched and did not find any other articles discussing this issue, however, I did find many xPAP forums where people were discussing their problems using xPAP therapy including congestion, sinus infections, and so on. I also noticed that humidifier tank “hygiene” does not seem to be taken seriously.

I decided to check this out with some preliminary tests.

Filling my humidifier tank with distilled water and setting the pressure at 4 cm H2O (flow rate of around 20 liters per minute) revealed that my system was basically free of contamination. I then added a little salt to some water and put that water into the humidifier tank. When I measured the condensate water from the machine at a pressure of 4 cm H2O, there was basically no contamination, however, when I increased the pressure to 10 cm H2O (with a flow rate of around 33 liters per minute), salt contamination was observed in the collected condensate.

This suggests that at higher flow rates there may be some turbulence causing some of the water to form an aerosol. While water vapor doesn’t support a transfer of contamination, an aerosol can.

My question for Dr. Raymond is how easily is endotoxin bacteria transported in an aerosol (compared to salt ions), and how much contamination is needed to have adverse health effects? The manufacturers of the xPAP equipment have some recommendations on humidifier tank cleaning, and any additional suggestions would also be welcome.

Thank you for your time."

I have no idea if they will actually publish it, but there seems to be some interest in this. If they do publish it the response from medical professionals will be most interesting.

I am in my late 50s and I remember we had an old Kaz glass vaporizer when I was a kid.
My mom always put a little bit of salt in the water following the instructions. So this makes perfect sense to me.

I would think the salt might inhibit the growth of mold or bacteria--but I have no idea how well.

I live on Cape Cod and our water is naturally salty. I have not had sinus trouble since I started with c-pap. I used to get terrible sinus infections and used nasal rinses etc. For the last 3 1/2 years I hardly even get a bad cold.

This is interesting and certainly consistent with one of my favorite products, Neilmed sinus rinse (employing 1/4 t salt and 1/4 t baking powder dissolved in 8 ounces of distilled water).

As I understand the chemistry and physics involved, salt molecules are too heavy/dense to evaporate. I live near the Great Salt Lake, which is 10x saltier than the ocean, and I am not aware of situations where salt from the lake becomes entrained in water vapor from the GSL. However, I suppose that somebody smarter than me could make the case that other forms of vaporization (like wave action that results in an aerosol mist) could vaporize salt. In any event I am curious enough to dissolve a Neilmed packet into my humidifier tonight and see what happens. I don't think it can do any harm.

SleepGuy, Here it is Friday. Did you survive?