Apnea Forum Posting

Posted by ChuckS on September 29, 2000 at 07:31:08:

In Reply to: Re: Wacky CPAP...How do I build manometer? posted by DENNYBOP on September 27, 2000 at 21:42:55:

This post is long, because it has several ideas and a lot
of detail. Some of these ideas could be used with other
people`s home-brew manometers or even a real one.
The simple thing is to use the long CPAP hose as the manometer.
I put the CPAP on top of my car. I connected the long hose to
my humidifier and let it go down and back up. I put somewhat
more than 20 cm of water into the hose. I turned on the CPAP and
the pressure pushed the water down one side asnd up the other.
Theoretically, the difference in height of the
2 columns of water in cm should be
the pressure. Part of the reason for doing this outside is that
I had concern that the water may splash out the hose. If
there is too little water, that may happen. After I was sure
that wouldn`t happen, I rolled up the car window to gently clamp
the end of the hose to free up a hand.
There are a few problems with this. My CPAP hose is hard to
see through. More on this below. I don't want to bend
the hose too much at the bottom,
so the 2 sides are far apart, making it difficult to measure the
difference. I think a solution to this is to use a carpenter's
T-square. You could eyeball it to keep it reasonably level, or
tape a small level to it. Some have a level. In the US, most
levels are in inches. You could tape a metric scale to it or
translate. To translate with a calculator, for example 3-5/8
inches, do "5 divided by 8 + 3 = times 2.54="
The first "=" may only be needed for scientific calculators,
but it won`t hurt for anything. 2.54 in the number of cm to
an inch.
I also used it while wearing my mask. I made a "T" fitting
with PVC pipe and a PVC "T" fitting. I found the size PVC
that my hose fits. Tou could take your hose to the hardware
store to check the size. I cut 3 pieces of pipe and beveled and
smoothed them. After I cut the first piece of pipe, I
chould have put it into the "T" and put the hose onto it to see
if I had cut it the right size. It was close enough, though. The
PVC glue said to use primer for pressure applications. I
think this is fairly low pressure, but I used primer
anyway. After it dried 24 hrs, I connected a short hose from
a nebulizer from the humidifier (or it could have been the
CPAP) to the "T". I then ran the long hose from the "T" to
my mask, which I put on my face normally. I connected a
spare CPAP long hose to the other "T" fitting to be the
manometer, as described above. In this arrangement,
breathing causes the level to bounce around. To get
a good reading you probably have to hold your breath.
Maybe it's time for a sick joke. Some may think a
"man"ometer is something like a macho-meter
This arrangement may work if your CPAP changes pressure
while you're looking at it. If not, you'd want to set
something up next to your bed. You could use some cheaper
clear tubing for the manometer. This would be easier to read
and you bend it more. you could duct-tape it to the "T"
or find some PVC fitting that will fit some tubing or
some of each. I found some tubing that fit normally, but
it was quite stiff. [You could also put somebody else's manometer
on the "T".] If the CPAP is on the floor, run the tubing
up, down, up, and then down a little to keep dust out of
the end. I'd use a board to attach the tubing to and
then put feet on it or lean it on the wall or furniture.
It could also be attached to the wall or furniture.
There are combination clamp/nails that could work.
Have the middle down and up segments close to each
other and put a metric scale between the segments.
You'll probably have to subtract the 2 numbers the
columns af water are next to. Put
water into the middle section through the loose end and
position the open end down. Put a flashlight where
you can reach it without changing your position.
Another thing you could do is to feel the air
coming out of the exhaust vent in your mask. Wetting
your hand will probably make it more sensitive. You
could have some water near your bed. You may be able
to tell a difference in pressure this way,
although it's surely less accurate than the other way.
My CPAP seems to be very low pressure sometimes, so
I'll probably do this myself.

Follow Ups:

• Or buy one? ChuckS 11:58 10/02/00 (1)
  • Re: Or buy one? Linda 12:13 10/02/00 (0)

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