Rhythmical Spikes in pressure?

[Ailu]

Ah, what a wonderful night's sleep I had! Couldn't wait to grab a cup of coffee and analyze the results.

Well um, I guess things look pretty good... but what in the world are these rhythmical spikes in pressure all about?

[attachment=1572]

[Sleeprider]

Your profile does not say what machine you use, but it's not necessary. The Respironics PRS1 Auto is programmed to evaluate pressure increases of 2 cmH2O at regular intervals. If it does not find an improvement, it drops the pressure back to minimum or until it detects flow limitation or snores. Your chart is absolutely typical for that machine.

[Ailu]

Yep, it's the Respironics. Thanks for reminding me to update my profile, I'll do that now.

[MobileBasset]

Your profile does not say what machine you use, but it's not necessary. The Respironics PRS1 Auto is programmed to evaluate pressure increases of 2 cmH2O at regular intervals. If it does not find an improvement, it drops the pressure back to minimum or until it detects flow limitation or snores. Your chart is absolutely typical for that machine.

I did not know this about the PR. 2 cm seems like a big step, how is this not a disruptive characteristic? I'm pretty sure I would "feel" these pulses. Does it take a series of flow limits or some other happening to trigger these spikes or is it a given regardless of flow pattern? Since I haven't heard about this before I guess most people don't have a problem with it.

[vsheline]

I did not know this about the PR. 2 cm seems like a big step, how is this not a disruptive characteristic? I'm pretty sure I would "feel" these pulses. Does it take a series of flow limits or some other happening to trigger these spikes or is it a given regardless of flow pattern?

Actually, theses are slow adjustments rather than pulses.

On the waveform posted, each major horizontal division was 20 minutes, and each minor division was 2 minutes.

The pressure appears to ramp up slowly, taking around 2 minutes for each 1 cmH2O while ramping up, and the pressure ramps down slowly, taking around 1 minute while ramping down.

Indications of Flow Limitation will cause the machine to increase the pressure (IPAP) right away.

Separately, the slow background variation periodically raises the pressure to see if the Flow waveform looks better (smoother and less flattened) if the pressure is higher (in which case the pressure will remain at the higher level), or if the Flow looks just as good when the pressure is lower (in which case the pressure will remain at the lower level).

[MobileBasset]

Thanks for the information. I notice the slope on decrease is often twice as steep as the increase and I don't see the correlation between the spikes and the event flags. Maybe the flow data would show that. Anyway it all seems rather intense. I need pressure support but am very sensitive to the level so I know I would definitely try a PR out before I would decide to buy.

[zonk]

Ah, what a wonderful night's sleep I had! Couldn't wait to grab a cup of coffee and analyze the results.

Well um, I guess things look pretty good... but what in the world are these rhythmical spikes in pressure all about?

Is this nightly occurrence or just one-off?
Comparison with EncoreBasic would be interesting

I'll get a coffee too

[Ailu]

Well I've only had the machine 2 nights. And the first night, I was a mess. But the 2nd night was bliss, and the rythmical spikes are from that night. I'll watch the next couple of nights and report back on them...

Ah, what a wonderful night's sleep I had! Couldn't wait to grab a cup of coffee and analyze the results.

Well um, I guess things look pretty good... but what in the world are these rhythmical spikes in pressure all about?

Is this nightly occurrence or just one-off?
Comparison with EncoreBasic would be interesting

I'll get a coffee too

[quiescence at last]

just keep in mind - these routine blips are a sign of things being good. the pressure change is gradual and not even 2 cm. looking carefully, it is 1.5 cm.

see post http://www.apneaboard.com/forums/Thread-...#pid101641

It is important to note - the study uses a signal generator to mimic normal and then flow limited breathing. It clearly shows that the algorithm bumps up pressure periodically even when no flow limitations occur.

QAL

[Mosquitobait]

Huh. I found the pressure going up and down so quickly was not helping me (I have a Respironics loaner). It got so bad that I finally changed from auto-pressure to straight pressure at 11. I'm still not sleeping great, but I'm not as compelled to nap as I am without a cpap. I really didn't expect that. Even though the algorithms are different, the results should have been somewhat similar based on DocWils experiment. Of course, not all my problem is cpap related - I still have the restless legs although the new treatment (magnesium & zinc) has helped.

Still awaiting my replacement Resmed Airsense for Her.

I'm glad you are feeling the help from the cpap, Ailu. It took me a week before I started to see improvement (no need to nap), the first time out with my former used machine.