RPT's: technical question

WindFlyer · Post by **WindFlyer** » Fri Dec 01, 2006 9:45 am

After reading posts about "air is forced into my lungs at night" and soforth... it begs the question: Does CPAP really affect partial pressure of O2 in the lungs? 10-15cm of H2O is hardly a large amount of pressure in the grand scheme of things, and unless you have O2 connected to your machine I don't think you're changing the partial pressure at the alveolar level are you?

Thanks in advance...

curtcurt46 · Post by **curtcurt46** » Fri Dec 01, 2006 9:57 am

My opinion is that you are changing the static pressure ever so slightly. This has no effect on the lung unless the lungs are compromised with some obstructive lung disease.

RestedGal may have described 10cm of pressure as what you would experience 10" down in your swimming pool.

O2 level are not changed.

SelfSeeker · Post by **SelfSeeker** » Fri Dec 01, 2006 11:35 am

A CPAP is not meant to get air to the lungs. The pressure that is recorded is the pressure of air needed to keep the airway open (acting like a splint) so that the air you breathe can get to your lungs.

Other machines would force air in.

[quote="WindFlyer"]After reading posts about "air is forced into my lungs at night" and soforth... it begs the question: Does CPAP really affect partial pressure of O2 in the lungs? 10-15cm of H2O is hardly a large amount of pressure in the grand scheme of things, and unless you have O2 connected to your machine I don't think you're changing the partial pressure at the alveolar level are you?

Thanks in advance...

Snoredog · Post by **Snoredog** » Fri Dec 01, 2006 11:49 am

if your airway stayed widely patent you would get normal O2.

cpap restores normal O2 by keeping the airway open (with normal lung function).

Goofproof · Post by **Goofproof** » Fri Dec 01, 2006 10:09 pm

The chest discomfort, some new to XPAP feel, is the chest being forced to a larger size by the XPAP pressure, and the required effort to push that pressure out.

They ran tests on my breathing output volume, it increased 10% after 8 months of XPAP treatment. The extra pressure forces the lungs to inflate more, and the chest muscles get stronger working against the machine. That's why I slowly went from CFlex 3 to 1, to build up breathing power.(I have trouble getting my O2 level high enough) 93% is good for me.

rested gal · Post by **rested gal** » Sat Dec 02, 2006 2:32 am

The swimming pool post Curt mentioned was here:
viewtopic.php?t=13632

I found several explanations in these topics helpful:

Feb 28 2005 subject: Science behind CPAP Pressure
rwguinn wrote:
I have posted what the pressures mean elsewhere.
for example, 25cm H2O is about 10 inches of water. That is a low pressure. To demonstrate:
The center of my lungs is about 10 inches below my chin. If I stand in a swimming pool, with the water up to my chin, the water exerts a pressure exactly equal to what a person on maximum CPAP therapy of 25cm H20 would feel. The difference is that it helps me exhale, and I have to inhale against it.
CPAP helps me inhale, and I have to exhale against the pressure.
Neither one helps me breathe. It is static pressure.

Aug 08 2005 subject: Who thinks what? And what the experts say? Does the pressure

May 02 2005 subject: Formula for calculating volume of air for given pressure

ozij · Post by **ozij** » Sat Dec 02, 2006 1:33 pm

curtcurt46 wrote:.... may have described 10cm of pressure as what you would experience 10" down in your swimming pool.

10cm (ten centimeters) of presesur would be about 4'' (four inches ) down in your swimming pool!

O.

lvwildcat · Post by **lvwildcat** » Sat Dec 02, 2006 1:39 pm

Self seeker is exactly right -the CPAP pressure is the amount needed to splint your airway to stay open.It has nothing to do with added oxygen or forcing air into the lungs.

Mask

Additional Comments: Machine:Resmed S7 Elite; Oracle Mask(YES! My DREAM mask!!)

RPT's: technical question

RPT's: technical question

Re: RPT's: technical question