20 cm h2o means..20 centimeters of water..and that means?

DreamStalker · Post by **DreamStalker** » Mon Sep 18, 2006 1:04 pm

Goofproof wrote:
sinkem wrote:Just to put it in writing.
From HG45's web site: 20 CMH2O = .28 PSI
From http://www.1728.com/convpres.htm?b0=1++
20 cmh20 = 0.72255 psi

You don't suppose they were using distilled Water. Jim

Jim -

Your conversion is for "inches" of h2o not cm of h2o ... according to Pascal's Law it is referenced to distilled water.

- roberto

Goofproof · Post by **Goofproof** » Mon Sep 18, 2006 1:08 pm

DreamStalker wrote:
Sleepless in St. Louis wrote:
That is all for today’s lesson on hydrostatic pressure ... tomorrow's lesson ... how to build a CPAP system with advice from your friendly cpaptalk members.
Correct me if you think I'm wrong, but you really could create your own basis cpap if you had time on your hands and the inclination. For a motor you'd use a vacuum cleaner motor. You'd needd any type of reastat to control the speed of the motor. A home made water column to measure and adjust the flow and some duct tape to attach to your interface hose. You'd need a few other assorted hoses and clamps, but you really could do it. You may not want to actually use what you built but it would be a fun project for the Mc Gyver types.
I think I would stick to something smaller and quiter like an air pump for a fish tank ... a vaccum cleaner motor might cure you of the CPAP treatment for good by exploding your lungs.

- roberto

DreamStalker · Post by **DreamStalker** » Mon Sep 18, 2006 1:15 pm

Goofproof wrote:Invention of the CPAP for obstructive sleep apnea
The original CPAP device was the result of studies on obstructive sleep apnea being done by Dr. Colin Sullivan in Australia during the 1970's and 1980's. He along with 2 colleagues Michael Berthon-Jones and Faiq Issa were doing experiments on occlusion in humans. Dr. Sullivan was working with a patient that was about to undergo a tracheotomy for his apnea and really did not relish the procedure. An experiment was set up to try keeping the patient's airway open using some available tubing and a pressure device that was available. The experiment worked and proved to Dr. Sullivan that blowing air into the patient would allow the patient to sleep throughout the night.
From these early experiments, the first, crude CPAP devices were developed. At first, a mask was literally made and "glued" onto the patient. The first blowers tried were vacuum cleaners run in the reverse mode. From these humble beginnings, the modern CPAP devices of today were developed. New technologies and materials have helped make the CPAP the accepted method of treating sleep apnea.

They must have been wimpy vaccum cleaners back then because I'm pretty sure my Hoover Wind Tunnel vaccum would shoot a column of water 3 to 4 feet in the air.

- roberto

Goofproof · Post by **Goofproof** » Mon Sep 18, 2006 1:48 pm

DreamStalker wrote:
Goofproof wrote:Invention of the CPAP for obstructive sleep apnea
The original CPAP device was the result of studies on obstructive sleep apnea being done by Dr. Colin Sullivan in Australia during the 1970's and 1980's. He along with 2 colleagues Michael Berthon-Jones and Faiq Issa were doing experiments on occlusion in humans. Dr. Sullivan was working with a patient that was about to undergo a tracheotomy for his apnea and really did not relish the procedure. An experiment was set up to try keeping the patient's airway open using some available tubing and a pressure device that was available. The experiment worked and proved to Dr. Sullivan that blowing air into the patient would allow the patient to sleep throughout the night.
From these early experiments, the first, crude CPAP devices were developed. At first, a mask was literally made and "glued" onto the patient. The first blowers tried were vacuum cleaners run in the reverse mode. From these humble beginnings, the modern CPAP devices of today were developed. New technologies and materials have helped make the CPAP the accepted method of treating sleep apnea.
They must have been wimpy vaccum cleaners back then because I'm pretty sure my Hoover Wind Tunnel vaccum would shoot a column of water 3 to 4 feet in the air.

- roberto

DreamStalker · Post by **DreamStalker** » Mon Sep 18, 2006 2:30 pm

Goofproof wrote:Actually the first vaccum cleaners were hand pumped. .... Jim

Hand pumped? You would think they could have done better with Flintstone's technology

You probably have one of these laying around your cave don't you Jim?

- roberto

Goofproof · Post by **Goofproof** » Mon Sep 18, 2006 2:45 pm

DreamStalker wrote:
Goofproof wrote:
sinkem wrote:Just to put it in writing.
From HG45's web site: 20 CMH2O = .28 PSI
From http://www.1728.com/convpres.htm?b0=1++
20 cmh20 = 0.72255 psi

You don't suppose they were using distilled Water. Jim
Jim -

Your conversion is for "inches" of h2o not cm of h2o ... according to Pascal's Law it is referenced to distilled water.

- roberto

You are correct, and that site doesn't do it in cm. got to divide by 2.5
At least I am glad to hear they aren't using Heavy Water, I don't need the extra radiation, with all the Radon that's already filling my Cave. Jim

TerryB · Post by **TerryB** » Mon Sep 18, 2006 2:47 pm

Goofproof,
There is no input for cm of H2O the input available is inches of H2O thus the 2.5xxx times larger.

TerryB

Goofproof · Post by **Goofproof** » Mon Sep 18, 2006 2:57 pm

In the good old days, the hung the carpets outside and beat them clean with a heavy duty fly swatter.

I'm glad they came up with XPAP, I wouldn't want the wife staying up all night, beating me with a fly swatter, when I quit breathing. Jim

snoozie_suzy · Post by **snoozie_suzy** » Mon Sep 18, 2006 5:07 pm

I so totally needed to read this post first thing in the morning, not at the end of the day! You guys make me feel like I'm in highschool with all the extremely smart kids that would be fighting each other to get called on 1st with the answer and me praying the teacher didn't call on me because I didnt' have a clue.

I always used the excuse I started school very young and was almost a year younger than everyone in my graduating class, but I don't think that excuse pans out anymore!

I am very good common sense/street smart, not so good with equations or math or anything. My dad was a calculus/astro physicist professor so I might have been a slight disappointment in the math department to him!

Suzy

dllfo · Post by **dllfo** » Mon Sep 18, 2006 6:39 pm

Me and Suzy in the back row shaking our heads.

All that and smart too? Our cup runneth over. I understood the one about standing in the pool.

Thanks again

Goofproof · Post by **Goofproof** » Mon Sep 18, 2006 8:32 pm

I sat in the back for a reason, I stuttered, and didn't want to be noticed. If and when the teacher call on me for a answer, I would tell her I didn't know, be cause it was easier to get that out and maybe she would leave me alone.

It took some teacher two month or more to figure out I knew, and to just leave me alone. Good old school days, some bad memories. Then I got out ing the world and overcame it, but I still get excited and revert at times.

Jim

Now I stutter when I type.

tooly125 · Post by **tooly125** » Mon Sep 18, 2006 8:59 pm

I knew I shouldn't have skipped that class!

Ric · Post by **Ric** » Mon Sep 18, 2006 9:43 pm

dllfo wrote:My wife asked me exactly what does cm H2O mean? Can we compare it to Pounds per Square Inch (PSI) ?

This is from a previous post way back on nov 25 of last year, when GARYML pointed out that 10 cm H2O equates to 0.1422 pounds per square inch. Then some fool with too much time on his hands at the time pointed out that .....

Ric wrote:did YOU know,
that equates to about...

2.4908891 pieze
1.8683202 centihg
0.2490889 decibar
0.0024909 dekabar
0.0002491 hectobar
186.8320435 decitorr
24,908.8908333 barye
0.8333333 foot of head
1,868.3204351 centitorr
18,683.2043515 millitorr
0.0520233 kip/square foot
5.7803667 ounce/square inch
249,088.9083333 centipascal
644.6252176 foot of air [0 °C]
0.0254 atmosphere [technical]
2.4908891 sthene/square meter
24,908,890,833,333,328 attobar
0.0232247 ton/square foot [long]
8,161.7358807 inch of air [15 °C]
0.0245832 atmosphere [standard]
2,490,889,083,333.333 nanopascal
253.9999983 kilopond/square meter
25.3999998 centimeter of water [4 °C]
24,908.8908333 dyne/square centimeter
24,908,890,833,333,328,920,472,008,024e+28 yoctopascal

and the one you've all been waiting for.......

24,908,890,833,333,328,920 zeptobar !!!

(of course you will need to double those values to explain to your wife what 20 cm h2o represents. hope that helps )

-Ric

GoofyUT · Post by **GoofyUT** » Mon Sep 18, 2006 10:14 pm

Tim-

You described EXACTLY how Dr. Colin Sullivan constructed the FIRST CPAP device (in Canada I think, though he is Australian)!!!

Bravo!

Chuck

jeepdoctor · Post by **jeepdoctor** » Mon Sep 18, 2006 11:06 pm

[quote="Sleepless in St. Louis"]Just to add to what goofy said, it is a linear scale of measurement. 10 cm is twice as much volume of air as 5 cm. If you've ever seen a manometer, it works like that.

_________________

Not quite so, Sleepless. 10 cm H2O is a measure of pressure, not volume. There is a vast difference. Pressure is "push", volume is "amount."

For anyone who wants to see the arithmetic, a 34 foot (1036.32 cm) column of water exerts a static pressure of 14.7 psig. So 70.5 cm = 1 psig and 7 cm = 0.1 psig. Not a lot of pressure, but enough to blow up an air mattress. (I recently used my cpcp machine to blow up an air mattress -- it worked great!)

20 cm h2o means..20 centimeters of water..and that means?

Re: 20 cm h2o means..20 centimeters of water..and that means

Sleepless in St. Loius