Use a CPAP Machine With NO Pressure

[datguykirt]

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?

[scrapper]

I do not believe any of the machines will go below 4...........the ranges generally are 4-20 or 4-30.

[SleepingUgly]

I don't know about modifying files... personally that would make me nervous, but I'm no programmer. I've done 4cm, and would have liked to be able to collect data at 0 cm, but mine doesn't go lower either.

[Breathe Jimbo]

Absurd. With no airflow generated, the machine would have no reliable ability to detect events. Think about it.

[BleepingBeauty]

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?

That's just nutty.

Why do you need a baseline on your own machine to go by? Your diagnostic sleep study serves as the baseline for your untreated apnea.

I'd never even want to run my machine at 4cm (nevermind zero, if that was even possible). I'd certainly feel like I was suffocating. When it's time for a repeat sleep study, maybe I'll ask that they not titrate me for an hour or so, just to see how bad my untreated apnea is at that point. But that's about all the time I'd be willing to go without therapy.

[AndyCelt]

At 4cm (the start level of my ramp) I am gasping for breath! At zero I'd be suffocating... no thank you.

[LSAT]

If you had a titration, you were checked without the CPAP and then with the CPAP. Thats how your initial pressure was determined.
Your idea has no merit. Hook it up and go to sleep...see how you feel in the AM.

[archangle]

You'd be rebreathing your own exhaled air. Without any pressure in the mask, very little air would leak out the exhaust vent, so the O2 level in the air would go down and the CO2 level would go up. It would be like breathing in and out of a paper bag.

In theory, there's a risk of suffocation. Even if it didn't get that bad, it would be uncomfortable. Put your mask on, hook up the hose and don't breathe through your mouth for a while.

Now, it would be interesting to study airflow at zero pressure, but your standard CPAP machine and mask won't do the job.

[SleepingUgly]

I thought the masks were set up so you can breathe even if the electricity went out. The CO2 shouldn't be a factor unless the vent is blocked.

[snuginarug]

Absurd. With no airflow generated, the machine would have no reliable ability to detect events. Think about it.

Yes. Think about it. The detection of flow limitations are how events are detected by your machine. No airflow, no possibility to detect limitations of said air flow.

The diagnostic portion of your sleep study is done without a machine, and does not detect actual flow limitations. It records all kinds of other data, but not flow limitation because there is no way to introduce an air flow that would not alter the sleeper's events.

[archangle]

I thought the masks were set up so you can breathe even if the electricity went out. The CO2 shouldn't be a factor unless the vent is blocked.

Full face masks and oral masks have "anti-asphyxiation" vents that connect you to outside air if the pressure goes away.

Nasal masks depend on you reflexively opening your mouth if you're not getting fresh air through the nose, just like you'll do without a mask if your nose gets clogged. That's why medical professionals are horrified by the idea of mouth taping.

If you have a nasal mask, try unplugging your machine from power, wearing the mask and keeping your mouth closed. You may not actually suffocate, but you'll almost certainly feel like you're suffocating and open your mouth pretty soon.

[BrianinTN]

Let's be a little gentler, especially to a new poster. Frankly, while the idea is indeed untenable, I don't think the underlying objective and desire are totally crazy:
1) Some people have difficulty prying their full results out of their doctor.
2) Event scoring in the lab can differ a bit from how home machines score events.
3) There are lots of people with no insurance and no money to afford a sleep study, and for whom a pro bono study simply isn't viable due to travel considerations or whatnot. If a poor man's diagnostic test were possible, even if it had substantial accuracy issues, it would still be better than the alternative of doing absolutely nothing at all.
4) By the same token, there are those people who absolutely refuse to mention the prospect of apnea to their doctor, let alone go in for a PSG study, but who could maybe be cajoled by a family member to do something at home. I'm thinking of my dad here specifically, but I've read several other accounts here of people running into the same stubborn brick wall.

FWIW, I find a pressure of 4 cm/H2O to be pretty comfortable. That's definitely one of those things that seems to vary a lot by individual.

[rested gal]

The diagnostic portion of your sleep study is done without a machine, and does not detect actual flow limitations. It records all kinds of other data, but not flow limitation because there is no way to introduce an air flow that would not alter the sleeper's events.

Actually, during the diagnostic part of a sleep study (person wired up but not using a CPAP machine) they can (and do) detect and measure flow limitations.

When a person is all wired up for the diagnostic (no CPAP) sleep study, the little thingies (oronasal thermal sensor and nasal pressure transducer) sitting below the nostrils are to sense the amount of air flow occuring while the person is breathing in and out.

[SleepingUgly]

I don't know why people are saying this is crazy idea. It's a great idea, as I've had it before! After my surgery, I wanted to know how "cured" I was, and what I wanted was a way to get data at no pressure. The best I could do was 4cm of pressure. The stupid thing was that this didn't occur to me prior to my surgery, so I didn't collect pre-op data at 4cm of pressure. If I had, that would have been a very good comparison. Elena is a good example of someone who wanted to know how she was doing at no pressure if she slept on her stomach, and she didn't want to have to pay for a sleep study. The best she could do was 4cm of pressure.

In short, IMO, it is not a stupid or kooky idea.

[archangle]

I don't know why people are saying this is crazy idea. It's a great idea, as I've had it before! After my surgery, I wanted to know how "cured" I was, and what I wanted was a way to get data at no pressure. The best I could do was 4cm of pressure. The stupid thing was that this didn't occur to me prior to my surgery, so I didn't collect pre-op data at 4cm of pressure. If I had, that would have been a very good comparison. Elena is a good example of someone who wanted to know how she was doing at no pressure if she slept on her stomach, and she didn't want to have to pay for a sleep study. The best she could do was 4cm of pressure.

In short, IMO, it is not a stupid or kooky idea.

It's a great idea. It just won't work with no pressure and standard CPAP equipment.

Finding out how you do with 4 cm pressure is an interesting idea. You should realize, though that dropping your pressure to 4 cm has many of the same risks as sleeping a night without CPAP.

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

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.