[CPAP] Use Of Distilled Water In Humidifier

[philipquillen]

I recently upgraded from a Resmed S8 to a Resmed Airsense S10 Autoset machine. Embossed on the top of the humidifier chamber is the phrase "Distilled Water Only".

Is there some specific reason for this advisory? I am assuming that the humidifier chamber is the last element in the airflow chain .. just before the air is fed to the hose.

Is the use of distilled water really required? Is this a medical issue or simply a machine maintenance issue? I used my S8 for eight years using high quality well water dispensed through a Brita filter without any problems. Well that is besides not being able to effectively clean the S8 humidifier chamber .. aesthetically a lovely piece of work but from an industrial design perspective, zero maintainability .. but I digress.

Any thoughts?

[DocWils]

There are good design and maintenance reasons to use distilled water, including avoiding build up of various distillates in the chamber, but a health reason as well - bacterial and/or fungal build-up is a problem that humidifiers have and using distilled water is one way to keep that at a minimum, especially if you are not washing out your tank with hot water and soap every day and blow drying it. These colonies can transfer up the tube as well, carried by the air flow or hitching a ride on evaporatae, so your tube and hose can also get infected.

There has been considerable debate in this forum about the use of distilled water and what constitutes distilled water and if is necessary to use pure distilled water, some of the opinions are very firm, based on solid reason but not experimentation. I decided to answer it by getting some students to borrow a few machines from the sleep lab and use them for a few weeks, some with and some without pure distilled water or various forms of "similar/like distilled" water, each with varying cleaning schedules, and taking daily swabs of the tank, outlet tube, hose and mask (nice thing about working in a hospital - labs are available to culture samples with ease). The results clearly pointed to the advantages of pure distilled water both in maintenance and in health. Sorry, I cannot publish the results here - one student has decided to follow this up for a part of a thesis on colonial dynamics in health services devices at my encouragement, and therefore gets data and publishing priority over me. But this should put paid the debate, although I know it won't. As I said, lots of firm opinions here. For those who can wait two years (and can read German), I will point a link to the thesis once it is published.

[Napmeister]

Thanks Doc, appreciate the insight. I'll stick to my distilled water regime.

[OpalRose]

Same here, distilled water is fairly cheap. It just makes sense. Why take a chance of having bacteria buildup and possibly breathing this in.

[philipquillen]

Thanks for the input Doc .. will switch to distilled water.

[trish6hundred]

Hi philipquillen,
WELCOME! to the forum.!
There are some threads here on the board about using distilled water versis other water.
I have used distilled water since I started therapy.
Hang in there for more responses to your post and much success to you with your CPAP therapy.

[PaytonA]

There are good design and maintenance reasons to use distilled water, including avoiding build up of various distillates in the chamber, but a health reason as well - bacterial and/or fungal build-up is a problem that humidifiers have and using distilled water is one way to keep that at a minimum, especially if you are not washing out your tank with hot water and soap every day and blow drying it. These colonies can transfer up the tube as well, carried by the air flow or hitching a ride on evaporatae, so your tube and hose can also get infected.

There has been considerable debate in this forum about the use of distilled water and what constitutes distilled water and if is necessary to use pure distilled water, some of the opinions are very firm, based on solid reason but not experimentation. I decided to answer it by getting some students to borrow a few machines from the sleep lab and use them for a few weeks, some with and some without pure distilled water or various forms of "similar/like distilled" water, each with varying cleaning schedules, and taking daily swabs of the tank, outlet tube, hose and mask (nice thing about working in a hospital - labs are available to culture samples with ease). The results clearly pointed to the advantages of pure distilled water both in maintenance and in health. Sorry, I cannot publish the results here - one student has decided to follow this up for a part of a thesis on colonial dynamics in health services devices at my encouragement, and therefore gets data and publishing priority over me. But this should put paid the debate, although I know it won't. As I said, lots of firm opinions here. For those who can wait two years (and can read German), I will point a link to the thesis once it is published.

I do use distilled water but there are a few things in this presentation that are questionable to me. First, water from any moderate to large size community water service will very likely have as little bacterial infestation as distilled water. Secondly, if you are depending on distillation to remove or kill bacteria then why would not the heated humidifier do the same.

Your description of the experimental design leaves a lot of questions. I understand that you do not want to divulge too much in order to protect this student's thesis. My initial questions are along the line of:

Were the masks and tubes disinfected after each use?
What types of bacteria were found in hoses and masks?

I do not know if you feel that you can divulge the answers to those questions but I would be interested in knowing if you feel that you can.

Best Regards,

PaytonA

[Sleeprider]

DocWils, in the study you mentioned, is the maintenance and daily cleaning controlled? In other words, do both the distilled water group and tap-water group use the same maintenance other than water source?

[justMongo]

Were the machines and accessories cultured before the trial?

Was there at least one control sample; a machine that was not used but still subjected to daily cleaning ritual, and swabbed for culture like the rest?

(If used in a hospital -- perhaps already infected with MRSA.)

[DocWils]

I cannot go into too much detail, sorry, but the following criteria were used for each group - one week with daily cleaning and drying of tank, hose, mask, one week with alternate day cleaning and drying, one week with tank topped up over the week and the hose removed daily to hang, all shaken out on day 7 and dried, and one week with the water disposed of daily, the tank shaken out and returned to the machine, the blower then run for 40 minutes to ensure a dry hose and mask as well. The device, tank, tube, hose and mask were all given a thorough, hospital grade cleaning between each of the four sessions. Cultures were taken of the water before and after use, the tank before and after use, tube, hose from both ends and the middle and mask in various places. All machines and all parts were cultured before first use and after each thorough cleaning before the next phase of testing. In addition, each student was assigned a different type of mask, one ffm, one nasal mask, one nasal pillow, since each water type had three volunteers, so three masks between them, and a chance to study how various build-ups happen in each type of mask (you would be surprised by what we found, but I cannot say much about it due to thesis study - don't need to freak out, but I do advise you to clean your masks, of any type, pretty thoroughly at least every three days no matter what with a good dish soap and plenty of hot water, and then blow dry it with the machine)

The results were interesting enough that it warranted further study, more in depth, as part of a greater study of medical gear colonisation. The student in question is very likely headed into the microbiology department after graduating, methinks.

Tap water is not clean, it is full of microbes and lots of other things you may prefer not to think about, and picks up more on its journey through the pipes before it reaches your spigot, but for most places in the West it is safe to drink. But for use in a humidifier, where it is mildly heated (not enough to kill anything, btw, but more than enough to encourage colony growth) I don't think I would recommend it. Even Zurich water, which we used for tap water in the study, and is some of the best quality in Europe, showed kalk* build-up pretty quickly, even in tanks that were cleansed daily, as well as in the tube and hose entrance, and bacterial worths for sitting water rose rapidly.

Yes, this was a quick and dirty test, done as much for my own curiosity as to teach the next generation how to think clinically and critically, since I am of course a CPAP user and how much I need to clean the bugger is a good question for me. But the results were enough to get someone excited, and give us a good idea as to what works and what doesn't, water wise and cleaning wise (the latter, it turns out, depends on the water type and how you dry your gear, both which seem to dictate the frequency of cleaning and how you do it).

Properly distilled and stored pure distilled water will not have any bacterial build-up. De-ionised water will, although it is often sold for distilled water or in place of it. It is NOT the same thing, nor is filtered water.

*don't know the English spelling, sorry,only the German. Same sound different spelling.