Use a CPAP Machine With NO Pressure

SleepingUgly wrote:so I guess I don't know much about how to not asphyxiate myself.

Nor do I ... as a mouth taper for 7 years now.

Please note I'm not saying that these things are "wrong." I'm just pointing out that there is reason for worry.

SleepingUgly wrote:

Also, just because you don't have any apneas at 4 cm doesn't mean you won't have any apneas without CPAP.

That is true if one assumes that 4cm is a therapeutic pressure. Certainly it's a pressure that can do something for some types of respiratory events, but I don't know if it's a therapeutic pressure for an obstructive apnea. It may eliminate hypopneas and relegate them to FLs or something. Who knows.

I'm assuming that some people get relief at 4 vs. 0. I know I was really suffering at 8 vs. 11.

SleepingUgly wrote:

Modifying the machine to go below 4 cm is theoretically dangerous due to CO2 accumulation. It would be dangerous even with a full face mask or oral mask with an asphyxiation valve. The asphyxiation valve works at 0 pressure. It might not work at 1 cm.

Interesting. I didn't know that. I didn't even know there wasn't an anti-asphyxiation valve on a nasal pillow mask, either, so I guess I don't know much about how to not asphyxiate myself.

I've never seen a nasal pillow or nasal mask with an anti-asphyxiation valve, but there may be some.

Once again, just because 10 people will wake up before they asphyxiate doesn't mean the next 10 people will all do the same. Especially if they're old, medicated, drunk, extremely tired, sleep derived, or suffering from other medical conditions.

By the way, I should say "anti-asphyxiation" valve. An "asphyxiation" valve would probably be a bad thing.

datguykirt wrote:Has anyone tried using the CPAP with no pressure to get a base line reading to use as a comparison to gauge the effectiveness of the treatment? Mine (S9 Elite) only goes as low as 4 cm H2O but I suspect that would be controlled by altering the XML file, ResScan.XML
Any thoughts on this?

As I understand it, an XML file is a method to provide parameters to a software program. The s/w has to have been written to look for and accept specific data from the xml file. If the s/w isn't looking for it, it's presence in the xml will have no effect on the s/w.

Now, as I mentioned in the other thread you started about editing the xml file, all data generation takes place inside the S9. The only interaction between Resscan and the S9 is that Resscan is a display medium for the S9 data, and operating parameters for the S9 can be written to the SD card through Resscan. When the card is inserted into the S9 the parameters are changed accordingly. When the SD card is used for this purpose all data on the card is removed. In the S9 it's the same as inserting a new blank card as far as data recording goes. All the allowable operating ranges of the S9 are in its firmware. You cannot force the S9 to operate at a setting, such as zero pressure, that the firmware is not programmed to accept. Also, you cannot input parameters from the S9 any different from what you can manually set via the clinician's menu. The only purpose for having Resscan write parameters to the SD card is so the sleep doctor can make changes to your machine settings without having to physically handle the machine.

So, the conclusion is the S9 is not internally programmed to operate at less than 4 cm of pressure, and since the Resscan xml file has no relationship with the S9 it cannot be used to make changes to the S9.

datguykirt wrote:Has anyone tried using the CPAP with no pressure to get a base line reading to use as a comparison to gauge the effectiveness of the treatment?Any thoughts on this?

Would not a pressure of 0 mean that NO air at all would come throught the hose?

StevenXXXX wrote:

datguykirt wrote:Has anyone tried using the CPAP with no pressure to get a base line reading to use as a comparison to gauge the effectiveness of the treatment?Any thoughts on this?

Would not a pressure of 0 mean that NO air at all would come throught the hose?

Your lungs would drive air back through the CPAP machine and would suck air back up the hose. There is some resistance, but you can do it. Unplug your mask some time, stick the hose in your mouth and breathe in and out through it.

The problem is that you're rebreathing most of the same air over and over. You'd get a lot of CO2 buildup and low levels of oxygen. If you had a full face, oral, or hybrid mask, the anti-asphyxiation vent would keep air from flowing into the machine and that would screw up the measurement as well.

I suspect the software would get confused because the airflow sensors probably can't tell airflow in one direction from airflow in the other direction.

Once again, neat idea, but the standard CPAP equipment won't work.