CPAPtalk.com

Velbor
distilled water is not sterile water..... Or alternatively, what is reasonable and prudent (which may be different for each individual).

I suppose we could always consider the sterile liquid of urine for our humidifiers..........considering urine is considered a sterile astronaut drink. I empty, rinse and refill HH daily.....I've never topped off a glass of water throughout the day, I always start with a fresh glass. Yet, if I'm toting a bottle of water, I will drink until gone/finished before starting a new one after replacing the cap between drinks. Individual differences and individual susceptibility is likely a factor in our preference for topped off water or starting with water that has set on a shelf in a jug for 2 years!!!!

elg5cats

elg5cats wrote:I suppose we could always consider the sterile liquid of urine for our humidifiers

Aside from aesthetic considerations, that would be a bad choice. Just as with tap water, inorganic compounds would precipitate onto the chamber plate and walls. Worse, the organic compounds would likely become a sticky muck in the heated environment, and cause even greater havoc to the equipment. And since urine does contain organic substances on which microbial colonies (which would find their way in) could feed, just "topping it off" each night would likely result in a biological disaster as well.

Not a good choice. No, not a good choice at all!

My water that I use is from a reverse osmosis system I have installed in my home. Would you'll consider that comperable to distilled water?

Cindy

I think the recommendation to use distilled water in our humidifiers is to prevent mineral buildup. Although the distilled water we get from jugs (unless they are glass) is not 100 percent completely free of anything but H2O, it is close enough for the purpose. And it is by defintion sterile or the next thing to it.

Distilled water is used in the cooling systems of high power TV transmitters. In those transmitters, the high power tubes (klystrons, mainly) boil water into steam (called 'vapor cooling'), which extracts a great deal of heat from the tube. It is condensed into water again in a heat exchanger. Even though this water is effectively distilled hundreds of times a day, it is still amazing what it contains for impurities. And how corrosive it is (water, even distilled water is more corrosive than most people realize). (And it is still cleaner than the best distilled water you can get in a store.)

Bacteria cannot live in distilled water unless there are enough bacteria for them to feed on each other. Even then, it would be self-limiting (and the water would be far from being 'distilled'!)

Yes urine is supposed to be sterile. I have to remind myself of this fact each time a lion nails me with spray

DreamStalker wrote:
Sorry Joy ... your reference is wrong or misleading.

E. Coli is about 2,000 nanometers
Rhinovirus is about 20 nanometers
Water molecule is 0.278 nanometers

It is physically impossible for an object to hitch a ride on an airborne object 100 times smaller ... no can do. It would be like you trying to hitch a ride on a bumble bee. And if you were an E. Coli, it would be like you trying to hitch a ride on a nat

Well, my research was done 31 years ago , and now I have brain damage from long-term undiagnosed OSA . . . but I stand my ground nonetheless

Here's the deal, my cute little monkey friend:

Your stats on Rinovirus & E. coli are correct. Instead of nanometers (nm) . . . I usually use microns (same as micrometers) and abbreviated "µm". Rhinovirus 0.02 µm (or 20 nm) and E. coli 2 µm long (2,000 nm). However E. coli is spread by contact. The types of bacteria usually transported via droplets or water vapor aggregates are smaller, as small as 0.2 µm.

HOWEVER, We are NOT talking about transmission on "a water molecule". We are talking about water droplets (100-500 µm), and droplet nuclei (2-5 µm). A droplet of water vapor consists of "10 to the 11th power" or more water molecules. It is basic knowledge in microbiology that no researcher would dispute, whether environmental or clinical (especially in the hospital environment or surgical stage) that airborne bacteria are transported via water droplets, aerosols, hygroscopic droplet nuclei.

Now how all that relates to our discussion of CPAP humidifiers is not something I'd swear to, but it seems like one could make some applications that would at least seem to make sense. After all, there is a fan blowing air over the water, and that might form a kind of aerosol that would doubtless carry some microbes with it (assuming it's contaminated). We're dealing with a humidified environment, so the droplet or aggregate of water molecules mixed with microbes wouldn't easily dry out. (The dried out droplet nuclei are hygroscopic anyway so would attract more water molecules). And the guy or gal with the slimy humidifier would be on the other end of the hose with the air pushing the evil aggregates right into his/her respiratory system. Heck, I don't know but seems it could be a viable scenario. (Check out the CMAJ article below mentioning CPAP/BIPAP machines)

Hey, guys, here's a great powerpoint presentation from the CDC on "Aerobiology of Infectious Agents". It's a great review for this rusty old microbiologist, and I think, would be interesting for many of you too.
http://www.cdc.gov/niosh/npptl/resource ... 20Cole.pdf

Research done at the University of Calgary, Dept of Infectious Disease & Microbiology was published in the Canadian Medical Association Journal, and says:

Airborne transmission refers to dissemination of microbes within droplet nuclei (particles < 5 µm in diameter), which result from the evaporation of larger droplets (or exist within dust particles) and remain suspended in the air for long periods. Although most respiratory viruses are transmitted by droplet and contact methods, microbes that can spread via airborne transmission include the agents of measles, smallpox, tuberculosis and varicella–zoster.

The SARS outbreaks helped us to recognize the enhanced transmissibility of respiratory pathogens during respiratory procedures that may generate aerosol particles. These procedures have the potential to generate a multitude of large and small droplets, and the procedure itself may propel these droplets well beyond the 1-m radius usually associated with larger droplets.

Agreement about aerosol-generating procedures is not universal, but the use of nebulizers, high-flow oxygen, bronchoscopy, non-intubated ventilation (continuous or bilevel positive airway pressure), bag–valve ventilation and uncontrolled intubation are considered higher-risk procedures; they can cause the lines between droplet and airborne transmission to become blurred. What SARS has taught us is that the use of these specialized respiratory procedures can increase the potential for episodic localized airborne transmission and probably expand opportunities for fomite and droplet transmission.

Full article: http://www.cmaj.ca/cgi/content/full/175/3/263

Food for thought

Joy

Joy, your logic is reasonable, but this is an apples and oranges situation.

You are correct that microbes may be spread from water DROPLETS or any form of nebulizer.

This is the case with nebulizers, cooling tower droplets, cold air humidifiers that use physical action to create DROPLETS.
Pathogens can indeed be spread this way.

Some pathogens are indeed airborne, but xPAP does not increase the likelihood of these being a problem.
Think about all those people who do not use PAP and yourself who only uses it perhaps 8 hours a day.
All the other times you are breathing air that may have pathogens and the pap does not affect this.
In fact the filter in the pap would greatly decrease the proability of inhaling an airborne pathogen.

The HH produces water vapor, not droplets.
Otherwise your logic is rational, but your facts are not.

Just what was Obama thinking when he promised to close Gitmo?

timbalionguy wrote: ...........(water, even distilled water is more corrosive than most people realize). .........

Lion,

What, besides iron and iron-containing substances, will distilled water corrode?

Regards,

rooster wrote:

timbalionguy wrote: ...........(water, even distilled water is more corrosive than most people realize). .........

Lion,

What, besides iron and iron-containing substances, will distilled water corrode?

Regards,

It's true Rooster friend. Water is the universal sovent. It carves mountains and canyons. It is a dipole molecule that reacts pretty much with everything, thus making life possible.

Tomjax wrote:

The HH produces water vapor, not droplets.
Otherwise your logic is rational, but your facts are not.

Hi Tim,
Yes, I know HH produces water vapor. The fact is that "droplet nuclei" are different than "droplets", and they do exist in water vapor. Carrying microbes, they are light enough to move with air until they reach their destination. They are also hygroscopic, can grow in size and become droplets and finally settle out (depending on humidity, temperature, etc).

Here is the definition of droplet nuclei (from microbiologylprocedure.com):

Droplet Nuclei - Small droplets in a warm, dry atmosphere tend to evaporate rapidly and become droplet nuclei. Thus, the residue of solid material left after drying up of a droplet is known as droplet nuclei. These are small, 1-4µm, and light. They can remain suspended in air for hours or days, traveling long distances.

They may serve as a continuing source of infection if the bacteria remain viable when dry. Viability is determined by a set of complex factors including, the atmospheric conditions like humidity, sunlight and temperature, the size of the particles bearing the organisms, and the degree of susceptibility or resistance of the particular microbial species to the new physical environment.

If inhaled droplet nuclei tend to escape the mechanical traps of the upper respiratory tract and enter the lungs. Thus, droplet nuclei may act as more potential agents of infectious diseases than droplets.

http://www.microbiologyprocedure.com/ai ... nuclei.htm

I don't see an "apples and oranges" situation here related to an xPAP humidifier that has "slime" obviously growing in it.

True, "reasonably clean" CPAP units including their humidifiers are not likely to transport microbes any more than the air we breathe. What we are talking about on this thread are units that have not been cleaned for a long time and which some folks report as have slimy growth, indicating a concentration of some kind of microorganism (however it got there; perhaps a filter that hadn't been changed for months or years).

IMHO it is "possible", considering the air pressure in an xPAP and the movement of microbes via droplet nuclei, for microbes from a slimy humidifier to be transported to the cpap-er.

Joy

PS - I change my filters monthly, use distilled water topping it off nightly, and wash my humidifier every month or two. For me, that's "reasonable cleaning".

JoyD. wrote:Tomjax wrote:

The HH produces water vapor, not droplets.
Otherwise your logic is rational, but your facts are not.

Hi Tim,
Yes, I know HH produces water vapor. The fact is that "droplet nuclei" are different than "droplets", and they do exist in water vapor. Carrying microbes, they are light enough to move with air until they reach their destination. They are also hygroscopic, can grow in size and become droplets and finally settle out (depending on humidity, temperature, etc).

Here is the definition of droplet nuclei (from microbiologylprocedure.com):

Droplet Nuclei - Small droplets in a warm, dry atmosphere (aka apples)tend to evaporate rapidly and become droplet nuclei. Thus, the residue of solid material left after drying up of a droplet is known as droplet nuclei. These are small, 1-4µm, and light. They can remain suspended in air for hours or days, traveling long distances.

They may serve as a continuing source of infection if the bacteria remain viable when dry. Viability is determined by a set of complex factors including, the atmospheric conditions like humidity, sunlight and temperature, the size of the particles bearing the organisms, and the degree of susceptibility or resistance of the particular microbial species to the new physical environment.

If inhaled droplet nuclei tend to escape the mechanical traps of the upper respiratory tract and enter the lungs. Thus, droplet nuclei may act as more potential agents of infectious diseases than droplets.

http://www.microbiologyprocedure.com/ai ... nuclei.htm

I don't see an "apples and oranges" situation here related to an xPAP humidifier (aka oranges) that has "slime" obviously growing in it.

True, "reasonably clean" CPAP units including their humidifiers are not likely to transport microbes any more than the air we breathe. What we are talking about on this thread are units that have not been cleaned for a long time and which some folks report as have slimy growth, indicating a concentration of some kind of microorganism (however it got there; perhaps a filter that hadn't been changed for months or years).

IMHO it is "possible", considering the air pressure in an xPAP and the movement of microbes via droplet nuclei, for microbes from a slimy humidifier to be transported to the cpap-er.

Joy

PS - I change my filters monthly, use distilled water topping it off nightly, and wash my humidifier every month or two. For me, that's "reasonable cleaning".

.... or if you prefer ...

"possible" = apples
probable = oranges

Dreamstalker wrote:
.... or if you prefer ...
"possible" = apples
probable = oranges

I'm beginning to feel like we've learned well from dsm/SAG's sparring
There is no apples and oranges because "droplet nuclei" (ie, the dry residue from droplets) are hygroscopic, that is they take up water molecules in a humidified environment.

Velbor wrote:
Consider:
-- As water level drops during the night, microbes adhering to the walls of the chamber are exposed to the airflow stream and can become airborne. They need not "escape" from the water surface.
Absolutely; good to point out
-- Laminar flow over the water surface seems to be assumed. LOOK at the surface of the water in your humidifier as you breathe: on a macroscopic level there will be ripples; on a microscopic scale there will surely be larger "spray droplets". These are irrelevant to humidification, but they cannot be prevented without much fancier equipment than we use.
Interesting point.
-- Whether occasional microorganisms from the humidifier can "make it down the tube" in sufficient quantity to be clinically relevant to the person behind the mask has been argued on this forum, and studies quoted and criticized. Even so, they don't have to "make it down the tube" all at once: particularly if there is rainout, they can theoretically survive and thrive and migrate down the tube.
Technically speaking, some frank pathogens only need to be present in very small numbers for infection. The more relevant point to us, IMO, is that the air pressure can easily transport microbes in "droplet nuclei" (2-5 microns) or as "droplet nuclei in the process of attracting HOH molecules" before settling out.
-- It's argued that if only distilled water is used, there's nothing for microorganisms to feed on to stay alive. First, distilled water is not sterile water. Even if it were, that condition ends once the bottle is opened. And the air around us: The typical ResMed filter looks as though it will keep out insects. The typical Respironics dual filters probably do a bit better. What protects the blower outlet during the day? What protects the humidifier openings from airborne particulates? Postings in this thread and elsewhere support the proposition that microbes DO GROW in distilled water in humidifiers.
Well said.
Pretences of certainty are just that. The bottom line is, "Do you feel lucky?" Or alternatively, how paranoid do you choose to be? Or alternatively, what is reasonable and prudent (which may be different for each individual).

I agree . . . the bottom line is that we each have to decide on what is "reasonable" for us

I have a biology background and am not particularly manic about cleaning my equipment. I wash my cushion in warm soapy water every other day, wash the whole mask every couple months, top off my humidifier with distilled water every day, rinse out my humidifier every couple months, rinse out the hose...maybe once/year.

Of course, my residence is around 68F degress year-round. I might do it more often if my house got hotter.

The bottom line is that the human mouth has a ton more bacteria in it than your equipment ever should. It's also a matter of apples/oranges in that the microbes that grow at room temp in your equipment with almost no nutrient source aren't likely to grow in your body worth a damn.

In fact, you tend to need something with a cell wall to grow in distilled water, like fungi and molds. And those aren't going to get airborne unless they sporulate. By all means, if you find any fluffy or slimy "growths" in your equipment...clean it! But that sounds like a pretty rare event unless your intake filter is bypassed and you let it go a long time.

Apples and Oranges -- a Comparison
by Scott A. Sandford, NASA Ames Research Center, Mountain View, California

O.

Added missing link - thanks, -SWS.

JoyD. wrote:Here is the definition of droplet nuclei (from microbiologylprocedure.com):
Droplet Nuclei - Small droplets in a warm, dry atmosphere tend to evaporate rapidly and become droplet nuclei. Thus, the residue of solid material left after drying up of a droplet is known as droplet nuclei. These are small, 1-4µm, and light. They can remain suspended in air for hours or days, traveling long distances.

Emphasis in the above is mine. Remember that the molecular water vapor produced in a heated humidifier, unlike a raindrop or a sneeze, has no solid material and therefore cannot form a "nucleus" as defined above. The evaporative process leaves all "solid material" behind. Which is not to say that the output of a heated humidifier contains no particulates. Particulates can originate either from the incoming airstream, or from the chamber water due to airflow turbidity at the water surface. The number of these is likely to be small, and the risk of these few happening to "pick up" and carry microbes should be minimal, unless the water and/or the chamber is already heavily contaminated.

I am disturbed by the way in which several of the principles on "both sides" in this conversation, who are clearly highly educated, have used scientific concepts and terminology as blunt weapons with which to cudgel their opponents. Velbor

rooster wrote:What, besides iron and iron-containing substances, will distilled water corrode?

Rooster,

You might find the dihydrogen monoxide research site of interest. Dangerous stuff, it is....

http://www.dhmo.org/facts.html#CONCERN