Dreamstation pressure spikes

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jtech1
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Dreamstation pressure spikes

Post by jtech1 » Thu Jan 11, 2018 11:12 am

I had been running my Dreamstation at fixed min and max for a couple months, trying to narrow down a good pressure for me. I zeroed in on 9.5 giving me the best AHI. Last week, as next step in tests, I set range to 9.0-12.0. When I have an OA I do see the pressure ramp up for a while with plateau, and then back down... but, I am also seeing triangle spikes during times when there are absolutely no events or breathing issues happening. Can anyone tell me what they are?

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USMCVet
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Re: Dreamstation pressure spikes

Post by USMCVet » Thu Jan 11, 2018 11:16 am

Could be the pulse feature? Making sure your airway is open?:

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Pugsy
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Re: Dreamstation pressure spikes

Post by Pugsy » Thu Jan 11, 2018 11:22 am

The spikey sawtooth looking pattern you see on the pressure graph is just the normal auto adjusting test pressure probes.
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palerider
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Re: Dreamstation pressure spikes

Post by palerider » Thu Jan 11, 2018 6:28 pm

USMCVet wrote:Could be the pulse feature? Making sure your airway is open?:
The pressure pulses are 1cm pressure change for one second.

The spikes are 1.5 (iirc) changes over the period of several minutes.

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jtech1
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Re: Dreamstation pressure spikes

Post by jtech1 » Thu Jan 11, 2018 11:02 pm

Thanks... what I am seeing is 1.5 for 4-5 minutes... I am not sure WHY SleepyHead shows them as ONE point at +1.5 with ramp up and down taking 4-5 minutes... makes me wonder if it is really a ramp up and down that gradually... or if it is only logging points every 2 minutes, and this is the best resolution you get.

I understand the purpose of the 1cm for 1 sec pulses... but what is the purpose of the 1.5 pulse for 4-5 minutes? And is there a setting to disable it?

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palerider
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Re: Dreamstation pressure spikes

Post by palerider » Fri Jan 12, 2018 12:26 am

jtech1 wrote:Thanks... what I am seeing is 1.5 for 4-5 minutes... I am not sure WHY SleepyHead shows them as ONE point at +1.5 with ramp up and down taking 4-5 minutes... makes me wonder if it is really a ramp up and down that gradually... or if it is only logging points every 2 minutes, and this is the best resolution you get.
That's a really good question. Unfortunately, to get the answer, you'd need a logging pressure meter.

Sleepyhead reports what the *data* that's logged from the CPAP shows... But Respironics machines show very coarse pressure changes, whether that is what they actually do, or just what they log is open to interpretation.

Resmeds report much more detail about the pressure measurements.
jtech1 wrote:but what is the purpose of the 1.5 pulse for 4-5 minutes? And is there a setting to disable it?
It's some handy wavy BS about their 'special' algorithm, someone with more insider information alleged that it's something to do with their idea that if your sleep is disturbed, they don't want to do something blah blah and if it's good then blah blah something something...

It makes no sense whatsoever, the stated purpose of the pressure probes is 'to see if a pressure increase makes your sleep better" and if not, the pressure goes back.... HOWEVER...

If you look at enough respironics traces, you'll see that when the flow rhythm is nice and regular, the machine starts doing those *pokes* at you, like it's not satisfied with really good sleep... HOWEVER, if your breathing rhythm is irregular, then it does sweet FA, the exact time when a little more pressure might be advantageous to open up the airway and make the sleep a bit better... It's like they've got some variable check backwards in the code.... but they've been doing it that way for 8 years and 3 generations so far.

The takeaway is, if you've got spikes, the machine thinks you're sleeping great.... if your pressure is flatlined, you're not sleeping that good.

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Holden4th
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Re: Dreamstation pressure spikes

Post by Holden4th » Fri Jan 12, 2018 4:40 am

This was something I noticed with my PR760 as well and there were a quite a few of them.

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