APAP what causes increase in pressure

[plainhat]

OK I'm learning to look at my data and am wondering at how the machine decides to increase pressure. I'm looking at the graphs where I see it increase the pressure and don't see anything that indicates WHY it chooses to increase when it does. What am I missing?

[Wulfman...]

OK I'm learning to look at my data and am wondering at how the machine decides to increase pressure. I'm looking at the graphs where I see it increase the pressure and don't see anything that indicates WHY it chooses to increase when it does. What am I missing?

The two main things ALL APAPs/Autos use to trigger pressure increases are Flow Limitations and/or Snores.
Those two things are programmed into the machines' algorithms with the belief that they should precede Apneas.
Some people have them and some people don't.......preceding apneas. If they don't, then the apneas will occur without a pressure increase to prevent them. Even with FLs and Snores, if the starting pressure is too low and it takes too long for the pressure to increase to get to a point to where it needs to be to prevent them, then the apneas will also occur without the machine being able to reach an appropriate pressure.
Virtually NO APAP/Auto in a range of pressures will attempt to stop an apnea in process. For one thing, it takes at least 10 seconds for the machine to recognize whether the "event" (lack of breath) is actually an apnea. Once that 10 seconds elapses, the "event" will be recorded as an apnea.

Any more questions?


Den

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[avi123]

As a person’s airway begins to reduce in size a characteristic flattening of the smooth sinusoidal curve of normal breathing appears before clinical signs are apparent. CPAPs developers came up with algorithms that compared the shape of the airflow curve of a current breath with the average of previous breaths. At the commencement of flattening, air pressure is gradually increased to a level at which the shape returns to that normal breathing. The pressure then drops to a lower maintenance level.

[ChicagoGranny]

how the machine decides to increase pressure

For a more accurate description, read through this - http://www.resmed.com/int/clinicians/co ... nc=dealers

[Wulfman...]

As a person’s airway begins to reduce in size a characteristic flattening of the smooth sinusoidal curve of normal breathing appears before clinical signs are apparent. CPAPs developers came up with algorithms that compared the shape of the airflow curve of a current breath with the average of previous breaths. At the commencement of flattening, air pressure is gradually increased to a level at which the shape returns to that normal breathing. The pressure then drops to a lower maintenance level.

What you're stating is under the presumption that it can be done or certain characteristics exist.
Some people just have nasal obstructions or breathing issues like enlarged turbinates or deviated septums that make the "curve" flattened to begin with. For some people, increasing pressures may not only NOT restore the shape of the air curve, but may also make it worse. Consequently, the pressure keeps increasing and the Flow Limitations get worse. And, those breathing anomalies may not precede apneas either.


Den

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[ButtermilkBuoy]

Some people just have nasal obstructions or breathing issues like enlarged turbinates or deviated septums that make the "curve" flattened to begin with. For some people, increasing pressures may not only NOT restore the shape of the air curve, but may also make it worse. Consequently, the pressure keeps increasing and the Flow Limitations get worse.

The algorithms recognize persistent patterns of flow limitations (PFLs) and consider them as normal. The algorithms do not raise the pressure in response to PFLs.

[Wulfman...]

Some people just have nasal obstructions or breathing issues like enlarged turbinates or deviated septums that make the "curve" flattened to begin with. For some people, increasing pressures may not only NOT restore the shape of the air curve, but may also make it worse. Consequently, the pressure keeps increasing and the Flow Limitations get worse.

The algorithms recognize persistent patterns of flow limitations (PFLs) and consider them as normal. The algorithms do not raise the pressure in response to PFLs.

I don't know what the criteria is for which you're referring, but I've seen many cases of pressures maxing out on flow limitations. And, the increased pressures didn't reduce the flow limitations......and in many cases got worse.
In some cases, Flow Limitations can result from a reflex reaction from the increasing pressures.


Den

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[palerider]

OK I'm learning to look at my data and am wondering at how the machine decides to increase pressure. I'm looking at the graphs where I see it increase the pressure and don't see anything that indicates WHY it chooses to increase when it does. What am I missing?

The two main things ALL APAPs/Autos use to trigger pressure increases are Flow Limitations and/or Snores.
Those two things are programmed into the machines' algorithms with the belief that they should precede Apneas.

you really should read the link that Granny posted and update what you say to be more accurate.

[palerider]

OK I'm learning to look at my data and am wondering at how the machine decides to increase pressure. I'm looking at the graphs where I see it increase the pressure and don't see anything that indicates WHY it chooses to increase when it does. What am I missing?

here are links gathered by Robysue that will more than answer your questions:

viewtopic.php?f=1&t=111653&p=1072250

[Wulfman...]

OK I'm learning to look at my data and am wondering at how the machine decides to increase pressure. I'm looking at the graphs where I see it increase the pressure and don't see anything that indicates WHY it chooses to increase when it does. What am I missing?

The two main things ALL APAPs/Autos use to trigger pressure increases are Flow Limitations and/or Snores.
Those two things are programmed into the machines' algorithms with the belief that they should precede Apneas.

you really should read the link that Granny posted and update what you say to be more accurate.

I did and I have and I don't see anything that particularly contradicts anything I've said.

I'm even copying and highlighting the information from that website link to emphasize the points. And, I wasn't just talking about ResMed Autos because many users may not have ResMed APAPs or their more recent machines with newer algorithms.

Den

.


Lower average treatment pressures

The clinically validated1 AutoSet™ algorithm allows the delivery of lower average pressures1, without compromising efficacy
The pre-emptive response focuses on keeping the upper airway open
This can mean lower treatment pressures, increased comfort for your patients and fewer complaints of pressure-related side effects



AutoSet device's Three Lines of Defence

Click on the question to expand and reveal more information...

1. Flow Limitation

What is flow limitation?

A physiological change in the status of the upper airway
Causes a spectrum of closure, from subtle narrowing to partial collapse


What is the significance of flow limitation?

It usually precedes snoring and apnea. It is therefore, usually, the earliest sign of impending airway collapse3
Airway changes limit flow despite respiratory effort and in fact, cause increased respiratory effort. This may lead to arousal

How do I observe flow limitation?

The inspiratory flow time curve represents inspiratory flow limitation
The shape of the curve indicates the status of the upper airway. A normal upper airway is observed as a bell-shaped curve. The curve flattens with increasing flow limitation and airway narrowing/ closure

How does a ResMed AutoSet device measure flow limitation?
It calculates flow limitation on a breath-by-breath basis, detecting and responding to subtle changes

How does a ResMed AutoSet device respond to flow limitation?

If flow limitation is detected, AutoSet Spirit responds by gradually increasing pressure to bring the airway back to normal. Typically, this helps prevent snoring and apneas4
If no further events occur, AutoSet Spirit gently decreases the pressure, towards the minimum set pressure



2. Snore

What is snore?
Snoring occurs when the walls of the upper airway narrow and vibrate

What is the significance of snore?
It may precede obstruction of the airway and apneic events

How do I observe snore?

During snore, the inspiratory flow time curve flattens and the snore oscillation is super-imposed


How does a ResMed AutoSet device measure snore?
It has a pressure transducer that measures vibrations of the airflow

How does a ResMed AutoSet device respond to snore?

Increases pressure based upon the severity of the snore
If no further events occur, AutoSet Spirit gently decreases the pressure, towards the minimum set pressure



3. Apnea

What is apnea?
A condition where the upper airway becomes completely obstructed or severely limited

What is the significance of apnea?

Apnea involves sleep fragmentation, oxygen desaturation, and arousals during the night as well as several daytime symptoms5
Sleep Disordered Breathing (SDB) has been shown to be a significant contributing factor for hypertension,6,7,8 one of the leading risk factors for stroke and Congestive Heart Failure (CHF)

How do I observe apnea?

During apnea, the inspiratory flow time curve disappears, leaving a straight time line, since there is no flow


How does a ResMed AutoSet device measure apnea?
As the apneic cessation of airflow or breathing for more than 10 seconds

How does a ResMed AutoSet device respond to apnea?

Typically prevents apneas, by treating flow limitation and snore. These usually act as early signals for more severe apneic events
In the event of a sudden apnea that occurs without any preceding flow limitation or snore, AutoSet Spirit increases the pressure after the apnea has ceased to prevent further apneic events
Pressure response is based on the duration of the apnea
If no further events occur, AutoSet Spirit gently decreases the pressure, towards the minimum set pressure


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[palerider]

you really should read the link that Granny posted and update what you say to be more accurate.

I did and I have and I don't see anything that particularly contradicts anything I've said..

it's not so much contradictions of what you said, more the things you left out.

[Wulfman...]

you really should read the link that Granny posted and update what you say to be more accurate.

I did and I have and I don't see anything that particularly contradicts anything I've said..

it's not so much contradictions of what you said, more the things you left out.

< Yaaaaaawwwwwwnnnnnnnnn >


Den

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[palerider]

it's not so much contradictions of what you said, more the things you left out.

< Yaaaaaawwwwwwnnnnnnnnn >

yeah, I know, giving people good and accurate information is boring... give the half of the story that interests you, that's good enough, eh?

[Wulfman...]

it's not so much contradictions of what you said, more the things you left out.

< Yaaaaaawwwwwwnnnnnnnnn >

yeah, I know, giving people good and accurate information is boring... give the half of the story that interests you, that's good enough, eh?

Well, there was almost an hour from the time that the OP originally posted........and YOU didn't post any information, so I took a stab at it. I also hate to post loooooong posts that put people to sleep.......so I try to keep my responses somewhat brief and to the point. And, there already is an abundance of information on this forum and the manufacturers sites.

From now on, I'll just wait for you to post first. And then critique your posts.


Den

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[palerider]

Well, there was almost an hour from the time that the OP originally posted........and YOU didn't post any information, so I took a stab at it. I also hate to post loooooong posts that put people to sleep.......so I try to keep my responses somewhat brief and to the point. And, there already is an abundance of information on this forum and the manufacturers sites.

well, if you hadn't beaten the "APAPs raise pressure because of snores and flow limitations" incomplete bit into the dirt already, I might buy that...

From now on, I'll just wait for you to post first. And then critique your posts.

awesome, help keep me on my toes and make sure I'm providing *correct* information