CPAP machine with built-in filtration

lindalq wrote:
We understand that one reason the distilled water is to prevent mineral build up, but we thought the more important reason for distilled water was so the microbes in the water will not get into your lungs? Our researched lead us to this, which made us believe that the main reason for using distilled water is to prevent infection of the person? ‘the use of tap water (for sleep apnea machine humidifier) within Neti pots in Louisiana has led to a few reports of harmful parasite infections affecting the brain’ http://sleepdisorders.about.com/od/livi ... difier.htm

Furthermore, isn't another reason to not use tap water is because it contain minerals that you definitely don't want to breath into your lungs?

Thank you for your feedback. please let us know what you think.

(Also, regarding your comment about water getting into the hose. I think we meant about the humidified air. sorry for the misunderstanding)

Really? And you are college students? And you don't understand the difference between water vapour and rinsing your nose with water? How about doing some basic science research on water vapour and what it can hold.

lindalq wrote:Hi everyone,

Just want to get some of your opinion on this. Our fourth year biomedical engineering design project at University of Toronto involves improving on CPAP machines and this is one of the idea we brainstormed. We would definitely love some user feedback on this.

What do you think of a CPAP machine with built-in filtration system? This way, you don't have to especially buy/prepare distilled water for it. Instead just pour tap water into it and the machine will make sure the humidified air that goes into your hose is purified and filtered.

Since I had someone in my family go through this same process (different subject) at Johns Hopkins in USA, I understand your need for this input & would have been glad to help.

Her group of 5 won the University's award for their project.
And, they have 3 separate patents on what they developed.
Just waiting for someone to try to build what they developed to start collecting on those patents.

But, IMHO, you do NOT have viable areas (distilled water & filtration system) to work with.

There are so many other things that need to be done FIRST to improve CPAP machines.

Just search this forum.
There have been at least a few threads dealing with what "we" wanted in future versions of CPAP machines. At least 1 of those threads deals with the hopes for the ResMed S10 (which does NOT yet exist).

If I find any of those threads, I will post links here - but there are 6 workmen at my house right now changing out my central A/C & heat & I am a bit overwhelmed at the moment.

Our water is extremely hard. Anything other than distilled water is NOT an option.
My home distiller is very NOISY. I would not want it running at night--and especially not in the bedroom.
There are no stupid questions, but there are a heap of dumb ideas; this is one!

Ah, yes. I certainly do remember the search for my senior design project in biomedical engineering. I'm glad that was more than 35 years ago.

I echo the others in saying that your hunt is not over. You haven't found your project. Distilled water is only for avoiding lime scale buildup in the humidifier. Distilled water is cheap and easy to get for home use. Any water that is safe to drink is fine to use in the humidifier, so when travelling or camping one can use any available potable water. A built-in distiller would add unacceptable bulk, weight, and expense. CPAP machines are a pain to lug around as they are without adding to them.

Good luck in finding a suitable project.

Design project?
If I were in the same position, I would investigate the field of facial biometrics and 3D imaging
to design a mask fitting system that would enable a patient to find a mask that fits the individual face.
--across all manufacturers. A university approach would not be linked to one particular company,
for universal use and economy.
The current "system" may require the purchase of hundreds of dollars worth of masks by each patient,
most of which will never be used. It took well over a thousand dollars worth of masks for me to find my mask.
The waste is shameful!

And check out the last thread on crud left by water distiller - you would still be cleaning disgusting crud out of some container.

Hi Everyone,

Thank you so much for all your input. It seems like our idea of having built-in filtration will only work for some people, while unnecessary for others.

Please note that the built-in filtration is one of our ideas and with your inputs so far, we will probably decide to focus on one of the others. Wireless transfer of data is another idea, and please let us know what you think here: viewtopic/t93903/CPAP-machine-with-data-features.html

A lot of you mentioned that we should consider some other ideas, and we just want to outline below some of the key design ideas we eliminated due to the restrictions on our project and to show that we have considered some of the common problems mentioned on the forum as well as other websites.

To ensure all the group starts at the same point, our project is restricted to improving the Philips System One REMstar Auto CPAP Machine, and our design changes have to be able to be implemented in a 2 years time. The hypothetical scenario we're given is that sale of REMstar Auto is going down and that our goal is to implement a design change such that the sale will go up. Of course, this is a hypothetical scenario given to us by our profs. Specs about REMstar Auto can be found here: http://www.cpapsupplyusa.com/DS550HS-Re ... ifier.aspx

Some common CPAP problems we found are:

• - rainout -- however this is solved in the REMstar Auto, since it has heated humidifier tubing as well as adjustable humidity with respect to the environment humidity.
  - mask fittings ---- Mask problems seem to be the number 1 issue discussed. We had an idea with 3D scanning of a person's face and then 3D printing a custom mask to solve it. But we ran into 3 main problems with this idea: 1) we're asked to only change the machine and unless we're willing to couple the mask with the machine completely, we can't change only the mask 2) it seems that a person's face structure also changes due to different sleeping patterns and thus a perfect fitting is hard and the fitting also depends on the soft gel parts? 3) mask fitting would require clinics to have such equipment and technicians familiar with the equipment, which is difficult to implement in a 2 years time.
  - steep learning curve for CPAP --- seems like this problem is somewhat solved with the ramp feature as well as the many helpful support ideas provided on the net.
  - noise --- we were originally going to target this, but we've been getting different opinion in this since some people complain it's too loud while others said it's quiet. Also, some people say the machine is noisy whereas others say the mask is noisy.
  - size and weight - Decreasing these are not feasible unless we know the current components of the machine
  - water getting into the machine ----- REMstar Auto designed a seal prevent this from happening.

Please let us know what you think and if there are some problems that escaped our notice.

Thanks!

BlackSpinner wrote:And check out the last thread on crud left by water distiller - you would still be cleaning disgusting crud out of some container.

Hi BlackSpinner,

We meant coating the reservoir with hydrophobic material so that crud will not stick to it, thus allowing an easier cleaning protocol. Or even redesigning the architecture of it so that there are no edges.

(apologies for the link regarding tap water is unsafe. The link was provided to us and we did not read it as carefully as we should have. Thank you for pointing it out.)

OK, a couple more tentative ideas:
--Power outlets for some of the additional electrics that may populate our nightstands.
(this would be especially useful when traveling where outlets are in short supply)
--a larger, better display, with more information.

I am disappointed that no one is interested in using 3D scanning to help in mask FITTING.
A custom mask could be made less expensively with 3D printing; but that was not my idea.
Differences in the facial paradigms used by different companies would mean that masks are
already being made for different faces--but finding the right mask is usually limited to a vertical measurement only.
Three dimensional analysis of existing masks/sizes could help guide a patient to narrow down their choices,
saving hundreds of dollars, and preventing many therapy drop-outs.

I would bear in mind the fact that your instructors are probably teaching due to the fact that
they were unqualified for the jobs you hope they will train you for.

Been using tap water for years. I put in water jug and let sit open for a week so chlorine smell goes and have a months worth of water for free. Wash machine once a week and no problems. I think a water filter in the resivour seems like unneccesary expense and complication. Air quality is what I would look to improve if anything. I can buy or purify my own water but the surrounding atmosphere when not at home is something I cant. My home is set up to always be at positive pressure and intake air and recirculated air is filtered through media filter and activated charcoal filter. But when travelling who knows what is floating in the hotel air. More air moves through the machine than water. One of my companies does indoor air quality assesments and upgrades. Amazing how many mold spores and dust mites in most peoples homes and hotel rooms. The filtration system on cpap machines seems to be an afterthought in design process.

Hi chunkyfrog,

Thank you for the input.

--Power outlets for some of the additional electrics that may populate our nightstands. (this would be especially useful when traveling where outlets are in short supply)

What do you mean by power outlets? Could you not have purchased one from the store? How would having it integrated with the CPAP machine be better? Could you elaborate on this?

--a larger, better display, with more information.

We thought of improving the REMstar screen into a LCD screen, which shows your previous night's sleep data. So the next morning, you can quickly glance at your sleep pattern the night before. Would this be a helpful feature? Some people mentioned that they would just view it on their computer and some of the data that they want to see requires multiple screens, thus not feasible on a small LCD. And what more information would you like to see? other than AHI, snoring and leak?

What do you think of wireless transfer of data? Instead of using SD cards?

I am disappointed that no one is interested in using 3D scanning to help in mask FITTING. .... saving hundreds of dollars, and preventing many therapy drop-outs.

We were really disappointed when we were told that we couldn't change the mask, it seemed like most people have problems getting used to the mask as well as having an unfit mask which causes discomfort and leakage. Interesting idea you have regarding three dimensional analysis to access fitting of the mask. We saw that most of the fitting online requires you to print out a piece of paper and fit it onto your face, which is not accurate at all. Your idea might actually be feasible if we want to target improvements on masks. Because in addition to this, in our research, we saw a software which allows you to take photos of your face and then reconstruct it into a 3D file. I'm pretty sure most of the mask are injection molded, so some of them might already have a 3D CAD file for it and you might be able to combine these two together.

I would bear in mind the fact that your instructors are probably teaching due to the fact that
they were unqualified for the jobs you hope they will train you for.

Our instructors are not big on design. The course we're taking is more focused on regulatory pathways. Many medical devices does not reach the market due to the regulatory barriers, and they had hoped that this course will help us overcome this barrier.

Btw Linda, Remstar auto may still be used by people (mine's my backup), but it's no longer carried by major dealers and doesn't have a lot of features newer machines do. It was called the "Tank" because it was reliable, did a good job, etc. etc. but is too large.

I was definitely surprised that you're unfamiliar with 'data' as it's the #1 desirable (well, maybe after the 'right' mask) feature of new machines. The PR S1 and S9 Autoset (Resmed) are state of the art in that respect. Go to the lightbulb at the top of these pgs you can read all about data, not the least of which is the latest build by 'Jedimark', a member here who wrote a really good program called Sleepyhead... that even has a Mac version - something the previous ones did not. Go to Pugsy and look under her notes for links to it.

Data tells us how long we slept, how many Apneas and/or Hypopneas we had overnight ("AHI"), how many and what type of leaks occurred, what flow rates were, if we snored, and a whole bunch of other stuff. Very cool!

hueyville wrote:Been using tap water for years. I put in water jug and let sit open for a week so chlorine smell goes and have a months worth of water for free. Wash machine once a week and no problems. I think a water filter in the resivour seems like unneccesary expense and complication. Air quality is what I would look to improve if anything. I can buy or purify my own water but the surrounding atmosphere when not at home is something I cant. My home is set up to always be at positive pressure and intake air and recirculated air is filtered through media filter and activated charcoal filter. But when travelling who knows what is floating in the hotel air. More air moves through the machine than water. One of my companies does indoor air quality assesments and upgrades. Amazing how many mold spores and dust mites in most peoples homes and hotel rooms. The filtration system on cpap machines seems to be an afterthought in design process.

Hi hueyville,

Interesting idea. In addition to this, someone recently mentioned how the inflow filter to the CPAP machine is just a little sponge filter. Which also get dirtied easily.

However, we're having a little trouble understanding the reasoning behind your idea. During the day, wouldn't you be breathing the surrounding atmosphere? Could it be that the filtration system on CPAP machines is an afterthought because the air is what you breath during the day and that someone without the CPAP would also be breathing in this air during sleep right too? Unless you're saying that a person using CPAP is more vulnerable to the spores and dust mites in the surrounding atmosphere?

Thanks!

You wanted an idea – well here is one – from another thread here:

ThisIsMyUserName wrote:So I use a very low pressure (5 cm), which works great from an apnea perspective: I went from an AHI in the moderate-sever range to less than 1 on average. This is great from the CPAP perspective: no need for APAP, or complicated whatevers. I do have two questions, though: sometimes it feels like I can't get enough air, which I've heard is common at low pressures, but makes no sense to me at all, since at any pressure, the pressure is still well above room pressure. Second, I noticed a disclaimer on my mask info sheet that basically said that low pressures may not be enough to clear the CO2 from my breathing out, which can occassionally lead to, you know, death. I'm not all that worried, but it did get me thinking about whether the pressure is enough to fully clear excess CO2 and, if not, whether that means I'd be breathing low-oxygen air all night. Thoughts or knowledge on this?

If you can look up the vent rate for your mask and note the pressure used to determine that rate - then calculate the vent rate at your current pressure. What is the result?


At night my the amount of air I use averages some 6.5 liters per minute. However, a portion of my exhale will often reach over thirty liters per minute. If my vent rate is say 20 liters per minute then for a very short time air is being pushed back down the pipe. But then as I continue to exhale at a lower rate the air goes out the vent before inhale begins.

CO2 when increased in the blood tends to open up circulation. While part of me looks at the potential for a very low vent rate to not clear as much CO2 in the process of breathing with the mask and that the body would respond by increasing respiration which would make for a higher amount of not clearing CO2 at the same time the increased circulation tends to calm things down when in comes to breathing control so it would seem that a reasonable equilibrium might be found.

With EERS[1] the last bit of air exhaled becomes the first bit of air inhaled and the amount is consistent breath to breath. This tends to prevent hypocapnia during times of high air use (over breathing). But I suppose if the actual vent rate is too low it is possible that you could end up breathing a whole lot more resulting in a very large portion of the air being rebreathed. If that were the case simply making a bigger vent port would easily solve the problem.

[1]: Gilmartin G, McGeehan B, Vigneault K, Daly RW, Manento M, Weiss JW, Thomas RJ.
Treatment of positive airway pressure treatment-associated respiratory instability with enhanced expiratory rebreathing space (EERS).
Source: J Clin Sleep Med. 2010 Dec 15;6(6):529-38. Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Link: http://www.ncbi.nlm.nih.gov/pubmed/21206741


Ya know this suggest a potential vent system that could help many who intermittently over breath, which is suspect is all of us. Two vents. A small one near the entrance of the mask and a large one say some 150ml to 250ml or so down stream. So when the person is breathing quietly as one would expect at rest in bed there would be no rebreathed air. But if the persons breathing rose toward points where one could predict that hypocapnia would be a result the amount of rebreathed air would increase – to a point.

I think this could very much increase ventilatory stability while using CPAP.

I think that ventilatory instability is the greatest cause of people giving up on CPAP.

The 3D mask fit idea deserves 100 times more attention than all the other ideas mentioned here combined.

That said, WiFi or blue tooth data access would be nice.

The data we look at with Sleepyhead shows a series of graphs for the length of time we slept with events disbursed along the time line as the occurred. The current display technology simply provides an average over the full length of sleep. By looking at how the events were clustered or disbursed we can correlate them to arrousals for bathroom breaks or other events as well as pressure variations so we can fine tune machine settings.

I use reverse osmosis water in my humidifier and would not pay for a built in distiller or filter. After 2.5 years I could not tell the difference between my old reservoir and the replacement. I never did more than swish plain water in it every week or two.