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mrnetwurm
 
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Pressure pulse (what does it mean?)

Postby mrnetwurm on Thu Aug 11, 2011 7:39 pm

Hello, I have been using CPAP for about 3 weeks. I just looked at my data with SleepyHead software and I am puzzled by the "Pressure Pulse" events.
I have between 25 and 50 of these events each nite. I am using the C-Flex option level 1. I am not using C-flex plus.

PR System One REMstar Pro CPAP Machine with C-Flex Plus

Sometimes I wake up and the machine is pulsating air. It feels like its pushing me or trying to wake me up. Is this a pressure pulse ?

Here is a typical report for one night:
Clear airway apnea 4 events
Hypopnea 5 events
Obstructive apnea 10 events
Pressure pulse 35 events
RERA 2 events

Any thoughts ?

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Pugsy
 
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Re: Pressure pulse (what does it mean?)

Postby Pugsy on Thu Aug 11, 2011 7:49 pm

Pressure pulse is when the machine is testing the airway to see if it senses either a collapsed airway or open airway.

Your number of events needs to be divided by the number of hours slept to get an hourly index of each type of event.
Clear airway + Hyponeas + Obstructive events divided by hours of sleep = AHI (Apnea Hyponea Index)

Generally an AHI of less than 5 is considered okay though many feel like they need it to be lower to feel their best.

_________________
Machine: PR System One REMStar 60 Series BiPAP Auto with Bi-Flex
Mask: TAP PAP Nasal Pillow CPAP Mask with Improved Stability Mouthpiece
Humidifier: PR System One 60 Series Heated Tube Humidifier with Heated Tube
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SleepyHead download site
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Mr Bill
 
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Re: Pressure pulse (what does it mean?)

Postby Mr Bill on Fri Aug 12, 2011 9:34 pm

I have been informed recently there are no such thing as 'pressure pulses'. I think the air valves are capable of ramping up and down quite quickly so that it could be experienced as a 'pulse' but the air valves are totally under looped servo control at every flow/pressure. :)

_________________
Mask: EasyLife Nasal CPAP Mask with Headgear
Humidifier: Remstar Integrated Passover Humidifier
Additional Comments: Devon Medical PC68B Recording Pulse Oximeter, APC Back-UPS RS 1500
EPAP min=6, EPAP max=15, PS min=3, PS max=12, Max Pressure=30, Backup Rate=8 bpm, Flex=0, Rise Time=1,
90% EPAP=7.0, Avg PS=4.0, Avg bpm 18.3, Avg Min vent 9.2 Lpm, Avg CA/OA/H/AHI = 0.1/0.1/2.1/2.3 ... updated 02/17/12

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archangle
 
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Re: Pressure pulse (what does it mean?)

Postby archangle on Fri Aug 12, 2011 10:27 pm

Mr Bill wrote:I have been informed recently there are no such thing as 'pressure pulses'. I think the air valves are capable of ramping up and down quite quickly so that it could be experienced as a 'pulse' but the air valves are totally under looped servo control at every flow/pressure. :)


I don't think there are any valves. Just a fan controlled by a stepper motor.

I don't know what the person who told you there isn't a pulse meant. A "pulse" is simply a pressure change that goes up to a higher pressure and then drops back down to the original pressure. All pulses have a rise time and fall time for the pressure to go from one pressure to another. Perhaps they don't consider a pulse with a slow rise time to be a "pulse."

_________________
Machine: S9 AutoSet™ CPAP Machine
Mask: Swift™ FX Nasal Pillow CPAP Mask with Headgear
Humidifier: S9™ Series H5i™ Heated Humidifier with Climate Control
Additional Comments: Also SleepyHead, PRS1 Auto, Respironics Auto M series, Legacy Auto, and Legacy Plus
Last edited by archangle on Sat Aug 13, 2011 11:26 am, edited 1 time in total.
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Re: Pressure pulse (what does it mean?)

Postby robysue on Sat Aug 13, 2011 10:16 am

Given that the OP has a System One machine, it's reasonable to assume the question about Pressure Pulses is coming from looking at the Encore Pro or Sleepy Head flow wave forms where the PP's are indicated with little red dots.

In that case, Pugsy's answer is correct: The PP's are the algorithm that PR uses to determine the patency of the upper airway.

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archangle
 
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Re: Pressure pulse (what does it mean?)

Postby archangle on Sat Aug 13, 2011 11:31 am

mrnetwurm, are these pulses you feel one per breath as you breathe in and out, or are they faster?

Do they keep going for long periods of time, or just one pulse occasionally?

Is it a pulse, then a pause, then another pulse, etc.?

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Mask: Swift™ FX Nasal Pillow CPAP Mask with Headgear
Humidifier: S9™ Series H5i™ Heated Humidifier with Climate Control
Additional Comments: Also SleepyHead, PRS1 Auto, Respironics Auto M series, Legacy Auto, and Legacy Plus
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Mr Bill
 
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Re: Pressure pulse (what does it mean?)

Postby Mr Bill on Tue Aug 16, 2011 1:05 am

archangle wrote:
Mr Bill wrote:I have been informed recently there are no such thing as 'pressure pulses'. I think the air valves are capable of ramping up and down quite quickly so that it could be experienced as a 'pulse' but the air valves are totally under looped servo control at every flow/pressure. :)


I don't think there are any valves. Just a fan controlled by a stepper motor.

I don't know what the person who told you there isn't a pulse meant. A "pulse" is simply a pressure change that goes up to a higher pressure and then drops back down to the original pressure. All pulses have a rise time and fall time for the pressure to go from one pressure to another. Perhaps they don't consider a pulse with a slow rise time to be a "pulse."


Perhaps its a matter of time perception. What is a "pulse" to the eye is a carefully orchestrated ramping of flow upward or downward as required, from a higher pressure source (the blower), to a lower pressure (the sleeper). There are several posts along the way that examined this somewhat.

Hopefully, I am not quoting out of context... See my misunderstanding here...
viewtopic.php?p=616500#p616500
and the posts following...

Also I think I recall dsm that posted some very nice pics of blowers and the air valves but I cannot seem to find the thread. :oops:

Ah here it is...
viewtopic.php?p=616991#p616991

_________________
Mask: EasyLife Nasal CPAP Mask with Headgear
Humidifier: Remstar Integrated Passover Humidifier
Additional Comments: Devon Medical PC68B Recording Pulse Oximeter, APC Back-UPS RS 1500
EPAP min=6, EPAP max=15, PS min=3, PS max=12, Max Pressure=30, Backup Rate=8 bpm, Flex=0, Rise Time=1,
90% EPAP=7.0, Avg PS=4.0, Avg bpm 18.3, Avg Min vent 9.2 Lpm, Avg CA/OA/H/AHI = 0.1/0.1/2.1/2.3 ... updated 02/17/12

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archangle
 
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Re: Pressure pulse (what does it mean?)

Postby archangle on Tue Aug 16, 2011 1:28 am

Mr Bill wrote:Perhaps its a matter of time perception. What is a "pulse" to the eye is a carefully orchestrated ramping of flow upward or downward as required, from a higher pressure source (the blower), to a lower pressure (the sleeper).


OK, I understand. You're saying it changes gradually and isn't a "pulse."

In the scientific fields, we still call that a "pulse." A pulse may have a rise time of hours, but we still call it a pulse. For instance, a weather system could send a pulse of high pressure that takes a day to rise, stays that way for a day, then gradually drops to the original pressure over the next day.

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Additional Comments: Also SleepyHead, PRS1 Auto, Respironics Auto M series, Legacy Auto, and Legacy Plus
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Re: Pressure pulse (what does it mean?)

Postby dsm on Tue Aug 16, 2011 1:36 am

Mr Bill wrote:I have been informed recently there are no such thing as 'pressure pulses'. I think the air valves are capable of ramping up and down quite quickly so that it could be experienced as a 'pulse' but the air valves are totally under looped servo control at every flow/pressure. :)


Bill

The 'airvalves' used in Respironics machines are certainly used in the older Bipap models. To be honest, while I know they are in the Bipaps in the 'tank' case, I have no idea if they are used in the 'M' & Series or System One Bipap models. These machines could use them but could also use a variable speed fan. The only way to know for sure is to open a machine up - I did that with all most of the previous machines but haven't done so with any recent ones (too expensive).

In fact the only reason I know what is in the latest Resmed machines is because Resmed did a video showing their dual stage - dual impeller blower assembly in action & in 3D x-ray view.

But, because of the current high price of the Bipap models, it is quite probable they still use 'airvalves' as they are an expensive to manufacture solution & the price seems to reflect that.

Pressure Pulses are certainly used in the new Respironics Auto cpaps & also the newer Bipap AutoSV & the System One Bipap SV & System One Bipap Autos. The pressure pulse is used to determine if the airway is open or closed. They show up in the charts as little squares. Resmed use the FOT technique to achieve a similar result. The purpose is as previously posted in this thread, to decide if it is an obstructive event or a central. Some times they get it wrong :( but mostly it works well. :)

DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)

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archangle
 
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Re: Pressure pulse (what does it mean?)

Postby archangle on Tue Aug 16, 2011 2:02 am

dsm wrote:The 'airvalves' used in Respironics machines are certainly used in the older Bipap models. To be honest, while I know they are in the Bipaps in the 'tank' case, I have no idea if they are used in the 'M' & Series or System One Bipap models. These machines could use them but could also use a variable speed fan. The only way to know for sure is to open a machine up - I did that with all most of the previous machines but haven't done so with any recent ones (too expensive).


The PRS1 models 150, 250, 450, 550, 650, and 750 all use stepper motor controlled fans and no electrically controlled valves, according to the schematics. This includes BiPap Pro and BiPap Auto. I do not know what's in the higher level models.

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Machine: S9 AutoSet™ CPAP Machine
Mask: Swift™ FX Nasal Pillow CPAP Mask with Headgear
Humidifier: S9™ Series H5i™ Heated Humidifier with Climate Control
Additional Comments: Also SleepyHead, PRS1 Auto, Respironics Auto M series, Legacy Auto, and Legacy Plus
Please enter your equipment in your profile so we can help you.
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Re: Pressure pulse (what does it mean?)

Postby dsm on Tue Aug 16, 2011 2:42 am

archangle wrote:
dsm wrote:The 'airvalves' used in Respironics machines are certainly used in the older Bipap models. To be honest, while I know they are in the Bipaps in the 'tank' case, I have no idea if they are used in the 'M' & Series or System One Bipap models. These machines could use them but could also use a variable speed fan. The only way to know for sure is to open a machine up - I did that with all most of the previous machines but haven't done so with any recent ones (too expensive).


The PRS1 models 150, 250, 450, 550, 650, and 750 all use stepper motor controlled fans and no electrically controlled valves, according to the schematics. This includes BiPap Pro and BiPap Auto. I do not know what's in the higher level models.


Archangle

Thanks for that info - it sort of backs my suspicion that Respironics dropped the airvalve after the 'tank' models. It was a great idea but too expensive to manufacture compared to a single variable speed brush-less motor.

The one challenge they still seem to have is the wave shape their blower produces & the fact they still use BiFlex suggests it is the classic square wave pressure pattern. That doesn't seem to bother us users though.

Also, applying FOT vs a Pressure Pulse also reflects the different types of blower each manufacturer uses. Respironics may not be able to apply FOT with the motor they use. I am sure the airvalve could have done it. But, the pressure pulse does the job even if some users find it intrusive.

DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)

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mrnetwurm
 
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Re: Pressure pulse (what does it mean?)

Postby mrnetwurm on Tue Aug 16, 2011 5:32 am

Wow, lots of tech discussion here. That's great, I would love to take my machine apart, but I think I'll want until
its out of warranty and it needs some work. I do lots of tinkering on mechanical and electronic devices. It's funny,
my son (17) picked up this same trait but he didnt inherit the ability to put things back together.

When I was a teen, I had a motorcylce and much to my parents horror, I disassembled the entire transmission
and engine one day. They thought it would never run again. They were wrong, I cleaned, repainted, and had
it going again in no time.

In regards to my pressure pulses. It's definately something I notice at times. The machine wakes my from
my sleep by pulsing the pressure approximately once per second. I am usually aware of the pulses for about
5 repititions before it occurs to me that it wants me to breathe. And so I do.

My point here, is that I believe I stop breathing completely for longer than the machine will allow and its attempt
to determine airway status actually wakes me up and gets me breathing again. My sleep study did not reveal
any central sleep apnea, but I would'nt be surprised if this was the case now and then. I'm pretty sure that I
sometimes do this while awake also. While I'm watching TV or other relaxed activities. (typing at the computer for example)

Jerry

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Re: Pressure pulse (what does it mean?)

Postby robysue on Tue Aug 16, 2011 8:00 am

mrnetwurm wrote:My point here, is that I believe I stop breathing completely for longer than the machine will allow and its attempt
to determine airway status actually wakes me up and gets me breathing again. My sleep study did not reveal
any central sleep apnea, but I would'nt be surprised if this was the case now and then. I'm pretty sure that I
sometimes do this while awake also. While I'm watching TV or other relaxed activities. (typing at the computer for example)

Have you looked at the flow wave form data in SleepyHead? A pretty quick perusal of the data is all you need to confirm/reject your basic hypothesis, which is very reasonable by the way.

And our wakeful breathing is much less regular than our sleep breathing is supposed to be. After all, we are in conscious control of our wakeful breathing. And it is not at all uncommon for us to hold our breath for very short periods (10--30 seconds) when we're deeply engrossed in concentrating on something. And we decide to sigh and that often results in some "shallow" breathing afterwards. All these normal quirks can (and are) misinterpreted as sleep disordered breathing by the machine if they happen when we're AWAKE but wearing the mask with the CPAP on for some reason---such as watching TV or other relaxing activities done while in bed getting ready to fall asleep.

_________________
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Humidifier: PR System One Heated Humidifier
Additional Comments: PR System One REMstar BiPAP Auto (Series 50). Max IPAP = 8, Min EPAP=4, and Rise time setting = 3

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dsm
 
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Re: Pressure pulse (what does it mean?)

Postby dsm on Tue Aug 16, 2011 4:25 pm

mrnetwurm wrote:Wow, lots of tech discussion here. That's great, I would love to take my machine apart, but I think I'll want until
its out of warranty and it needs some work. I do lots of tinkering on mechanical and electronic devices. It's funny,
my son (17) picked up this same trait but he didnt inherit the ability to put things back together.

When I was a teen, I had a motorcylce and much to my parents horror, I disassembled the entire transmission
and engine one day. They thought it would never run again. They were wrong, I cleaned, repainted, and had
it going again in no time.

In regards to my pressure pulses. It's definately something I notice at times. The machine wakes my from
my sleep by pulsing the pressure approximately once per second. I am usually aware of the pulses for about
5 repititions before it occurs to me that it wants me to breathe. And so I do.

My point here, is that I believe I stop breathing completely for longer than the machine will allow and its attempt
to determine airway status actually wakes me up and gets me breathing again. My sleep study did not reveal
any central sleep apnea, but I would'nt be surprised if this was the case now and then. I'm pretty sure that I
sometimes do this while awake also. While I'm watching TV or other relaxed activities. (typing at the computer for example)

Jerry


Jerry

If you like looking at the insides of these machines, here are some of the models prior to the most renet 2 gens of machines. Essentially the same parts but the newer blowers are more sophisticated.

http://www.internetage.ws/cpapinfo

Choose the "look inside cpaps" item off the main menu

Enjoy :)

DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)

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Mr Bill
 
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Re: Pressure pulse (what does it mean?)

Postby Mr Bill on Tue Aug 16, 2011 7:26 pm

I can definitely hear some sort of spooling up when mine decides I need more pressure.

_________________
Mask: EasyLife Nasal CPAP Mask with Headgear
Humidifier: Remstar Integrated Passover Humidifier
Additional Comments: Devon Medical PC68B Recording Pulse Oximeter, APC Back-UPS RS 1500
EPAP min=6, EPAP max=15, PS min=3, PS max=12, Max Pressure=30, Backup Rate=8 bpm, Flex=0, Rise Time=1,
90% EPAP=7.0, Avg PS=4.0, Avg bpm 18.3, Avg Min vent 9.2 Lpm, Avg CA/OA/H/AHI = 0.1/0.1/2.1/2.3 ... updated 02/17/12


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