POLL: Machine Pressure is not accurate?

I've noticed some discussion about building your own manometer to test your machine to make sure its putting out the correct pressure. I know you can also purchase them.

I'm just curious.

Has anyone here gone to the trouble to test their machine and found out that it actually was putting out the wrong pressure? (example: Its set to output a pressure of 10 but instead its pumping out a 12)

If so, what did you do about it?

I've attached a poll to help figure this out.

I can't believe that ANY DME wouldn't do this as a free service....it take about 2 minutes.

You need a choice: I don't think it matters if my machine is accurate.

Your titrated pressure is just a starting point. You should be watching your numbers and homing in on the optimal setting...regardless of the actual empirical pressure that setting represents. Once you've found the setting that works for you, who cares what the number is?

LinkC wrote:You need a choice: I don't think it matters if my machine is accurate.

Your titrated pressure is just a starting point. You should be watching your numbers and homing in on the optimal setting...regardless of the actual empirical pressure that setting represents. Once you've found the setting that works for you, who cares what the number is?

Thats a good point, although the number is helpful for people that use more than one machine, or people that get their optimal pressures figured out on a loaner auto and then have to use their c-pap on the 90(95) % pressure.

Its just helpful to have some sort of standard for measurement so that you can track and discuss your therapy with medical professionals and just keep track of things your self in some sort of standardized measurement system.

I do admit, if you have an auto, it becomes less important since it will ramp up the pressure as needed.

I think the other concern people sometimes have is that perhaps over time, the machine becomes worn out and is either not accurate, OR looses accuracy during a session. (slowly loosing pressure over the course of several hours but returns to proper pressure after it has rested during the day) I'm not sure how likely that is, but I think I've read a few posts of people wondering about this.

blakepro wrote:I've noticed some discussion about building your own manometer to test your machine to make sure its putting out the correct pressure. I know you can also purchase them.

I'm just curious.

Has anyone here gone to the trouble to test their machine and found out that it actually was putting out the wrong pressure? (example: Its set to output a pressure of 10 but instead its pumping out a 12)

If so, what did you do about it?

I've attached a poll to help figure this out.

I tested one machine one time using the (cheapest) method I linked to in this thread.

viewtopic.php?f=1&t=49152&p=450105&hili ... er#p450105

And, it indicated the pressure in my machine was correct.


Den

I bought the Fisher & Paykel Water Manometer and have checked 4 machines. Two of them were older machines and two were fairly new. They were all right on the correct pressure.

Jerry

6PtStar wrote:I bought the Fisher & Paykel Water Manometer and have checked 4 machines. Two of them were older machines and two were fairly new. They were all right on the correct pressure.

Jerry

Thanks for the confirmation. My suspicion is that this will overwhelmingly be the case, but it will be interesting to see if there are any people that had a different story.

I've checked both my machines with manometers at the sleep lab and using my home-made manometer. (Yes, I got it working correctly.)
My M-Series Pro was off by just shy of half a cm lower than listed. The S9 is dead on target. I tested both at 11cm and 16cm.

I was sure that my cpap when powered directly via a DC power source was giving me less pressure then via an AC power source. I tested it and nope the pressure was exactly the same... about 1/4cm high on both.

Your Poll Got me to thinking Maybe I should check it. So I did.

I used a "machinist's scale" Graduated in 64ths of an inch (It's what I had, OK?)

Anyway, found the procedure in my "Provider's Manual" and checked it 7.5 cm Spot on and at 12 cm it was 12.065 cm +/- my eyesight

In other words there goes my excuses

I am not surprised at the results, the manufacturers must have a stated tolerance for that reading for the FDA; and current Good Manufacturing Practices probably indicate that you have to be within +/- minus a tenth of a cm or better (just my SWAG based on my experience with the FDA inspectors).

Now I plan to repeat the checks every 6 months or so to monitor performance for "issues".

Cheers,

Dave

My equipment comes along with me every visit to my sleep doc (I don't go often) for checking and pressure testing. Even tho I didn't buy my APAP from him, he tested & set it up initially...well, his RT did . Seeing him in a few wks, so it'll all go in with me: Escape (backup for now), AutoSet, power cords, humidifiers, reports, hoses, mask, the whole shebang.

Muse-Inc wrote:My equipment comes along with me every visit to my sleep doc (I don't go often) for checking and pressure testing. Even tho I didn't buy my APAP from him, he tested & set it up initially...well, his RT did . Seeing him in a few wks, so it'll all go in with me: Escape (backup for now), AutoSet, power cords, humidifiers, reports, hoses, mask, the whole shebang.

Thats probably a very good idea. Does your doc inspect your equipment when you bring it in?

I had my old Remstar Pro tested just after my last sleep study. It was a free service by the Provider.

I used that machine EVERY NIGHT and EVERY NAP from September 2002 until February 2008 and it was still right on!

After I bought my M Series Auto, I bought one of those little pressure gauges and I check the M Series one in a while. It has always been right on.

I am assuming that little pressure gauge device is fairly accurate.

Be sure to use distilled water in your manometers as the dissolved minerals in tap water will make it slightly heavier...

blakepro wrote:...Does your doc inspect your equipment when you bring it in?

Yup, tests everthing, examines/looks for leaks, holes, tears, the whole shebang. Took me several visits to remember to bring EVERYTHING for them to checkout...finally just made a checkoff list.