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Anybody know what these pressure pulses are for?
#1
Question 
I routinely get 1.6cm spikes in the pressure chart from my PRS Auto, and they don't seem to be associated with anything on the event chart.

Does anybody have any idea what they are and what they're for and/or are preventing?

If they're preventing something, would I be better off bumping up my minimum pressure a cm or two?

Whole Night

Magnified Section

Thanks!

Terry


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#2
That is so very, very weird.

With no corresponding breathing event, I am leaning toward machine hiccup. Especially since it seems to last almost exactly a full minute.

Second guess is my standby: aliens.
PaulaO2
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#3
(06-12-2015, 05:44 PM)PaulaO2 Wrote: That is so very, very weird.

With no corresponding breathing event, I am leaning toward machine hiccup. Especially since it seems to last almost exactly a full minute.

Second guess is my standby: aliens.

That's what I was thought. Aliens. 8-)

They seem to be in response to "something" since there are more of them on worse nights, but I'm not good enough at reading the pressure chart to know what's going on.
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#4
PRS1 Autos have a hunt-n-peck algorithm which raises pressure by 1.5cm H20 in Auto mode periodically to see if it improves breathing waveform. If according to its calc, there is no significant improvement, it ramps back down. I suspect this is what is happening in this case.

If this is how your waveform looks every night then you may actually try straight pressure equal to your lower limit of APAP pressure
or try lowering the lower limit of APAP pressure while in Auto mode.

Resmeds don't do this so they have a different characteristic waveform (aggressive ramps up and gradual slow decays in pressure)
Started APAP 4-20, Closed range to 7.5-14, then straight 8.0 w/ Aflex 3
RDI always below 1. But sleep much much better at straight pressure.
Started on F10, Tried Quattro Air successfully. Finally settled on P10.
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#5
(06-12-2015, 06:57 PM)AshSF Wrote: If this is how your waveform looks every night then you may actually try straight pressure equal to your lower limit of APAP pressure
or try lowering the lower limit of APAP pressure while in Auto mode.

That's really interesting.

If I lower the lower limit to 14, it still hunts around, but ends up spending more time @ 15 than 14, which is how I ended up at 15.

Depending on how my allergies are doing, auto-mode sometimes runs at 16 for most of the night, but that's not very frequent.

Is there anything to be gained with a straight 15? Do the pressure jumps of that size disturb sleep?

Thanks for the info!

Terry
[/quote]

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#6
Some people have found that straight pressure allows them to use a slightly lower pressure than an APAP would migrate to for their therapy. The APAP pressure fluctuations are also bothersome to some users to the extent that even though the apnea events are prevented, sleep is disturbed in the process which makes the therapy seem self defeating.

My brother has been on fixed pressure @ 15 cm for the past 12 years. Since he was having a little trouble with leaks at that pressure, I thought to do him a favor so I loaned him my APAP and set it for min 10 and max 15. Testing it for 7 nights, his AHI zoomed to the low 20's. That was very disappointing since on fixed 15 cm, he was getting AHI's of 1 to 1.8 regularly.

We are all different in this regard and if you are having trouble using the auto mode, then by all means try straight pressure for a few days. I suggest you try 15 cm fixed pressure for starters and see how it goes. It may be the answer you're looking for. For some of us, the auto mode is fine for a rough titration insight but for the most comfortable therapy, fixed pressure is better tolerated.
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#7
Philips Respironics has developed a new proprietary algorithm that differentiates obstructed airway (OA) versus clear airway (CA) apneas by a positive airway pressure (PAP) device. The OA versus CA detection algorithm works by delivering one or more pressure pulses when spontaneous breathing is not detected. The PAP device evaluates the response of the patient’s airway to the pressure pulse(s) and may identify OA or CA apneas based on the resulting patient flow; no flow indicates an obstructed airway.
http://www.healthcare.philips.com/main/h...apneas.wpd
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#8
(06-12-2015, 09:58 PM)Terry Wrote: That's really interesting.

If I lower the lower limit to 14, it still hunts around, but ends up spending more time @ 15 than 14, which is how I ended up at 15.

Depending on how my allergies are doing, auto-mode sometimes runs at 16 for most of the night, but that's not very frequent.

Is there anything to be gained with a straight 15? Do the pressure jumps of that size disturb sleep?

Thanks for the info!

Terry
As surferdude mentioned, APAPs seem to overshoot the max pressure needed to hold off all apneas by some delta. That is why doctors like to use APAP for titration and then set CPAP pressure to 90% pressure (in case of respironics). So if your APAP experience is thought of as a trial, then you should set your cpap pressure to 90% of last 30 days on ur respironics machine, and use that as a baseline cpap pressure. You can use this new pressure for 30 days and then increment or decrement by 0.5cm and iterate this way. This is exactly how I came to 7.5cm straight pressure. Although in my case my 90% pressure was closer to 9.5cm but I chose 8 as my first cpap pressure (I subtracted the 1.5cm hunt-n-peck pressure from my 9.5). I stayed on 8 for 30 days, my numbers looked good. Then I reduced it by 0.5cm and my numbers still look good.

About the pressure pulse algorithm that zonk mentioned, these pulses to distinguish between apnea types are much shorter in duration ( unlike the 1.5cm pulses in OP's case that are 2 minutes each). Also these pulses show up on pressure pulse event on sleepyhead and do not register on pressure graph.

My 2 cents. YMMV.
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#9
(06-12-2015, 11:01 PM)zonk Wrote: Philips Respironics has developed a new proprietary algorithm that differentiates obstructed airway (OA) versus clear airway (CA) apneas by a positive airway pressure (PAP) device. The OA versus CA detection algorithm works by delivering one or more pressure pulses when spontaneous breathing is not detected. The PAP device evaluates the response of the patient’s airway to the pressure pulse(s) and may identify OA or CA apneas based on the resulting patient flow; no flow indicates an obstructed airway.
http://www.healthcare.philips.com/main/h...apneas.wpd

That was my first thought too Zonk, but I have such a machine and the pulses are just that - a short pulse of less than a second - and they don't show on the Sleepyhead charts.

As well as that the auto pressure step-up in response to OA's appear to have a minimum duration much longer than 1 minute.
Disclaimer: The 'Advisory Member' title is a Forum thing that I cannot change. I am not a doctor and my comments are purely my opinion or quote my personal experience. Regardless of my experience other readers mileage may vary.
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#10
So last night I set it to a straight 15cm, and slept like a rock, although there were a couple of patches that would have needed 16-16.5 to fix, which is exactly where the machine was going. When I woke up I felt a little dopier than usual. I think I'll set it back to auto.

My best guess is that it's fixing something that it thinks is going to occur, but isn't reporting what it's doing.

Interestingly enough, the spikes occur exactly in the same areas that groups of prs1_01 markers show up in sleepyhead. Nobody knows what the markers means, but I get a bunch of markers at the same time as the pressure spikes.

[Image: esZDj0h.png]



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