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Set CPAP to APAP 90% pressure?
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pupcamper Offline

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Posts: 401
Joined: Nov 2015

Machine: PR DreamStation CPAP Pro
Mask Type: Nasal pillows
Mask Make & Model: AirFit P10 Pillows; Quatro Air FFM
Humidifier: DreamStation Heated Humidifier
CPAP Pressure: 10.5 cmH2O; no ramp; no C-Flex
CPAP Software: SleepyHead EncorePro

Other Comments: Lung cancer survivor since 11/2004; CPAP since 11/2015

Sex: Male
Location: Van Buren, Arkansas, USA.

Post: #1
Set CPAP to APAP 90% pressure?
I have been running my DreamStation CPAP Pro on auto trial for the last couple of weeks. During that time my 90% pressure has been a steady 10 cmH2O. Is that what my straight CPAP pressure should be set to?

"....respiration,—a troublesome practice, but one which custom has rendered necessary to our easy existence...." Oliver Twist, Charles Dickens- 1837

I use FlashPAP to load data from a FlashAir III wifi sd card in my machine to my computer and display it with SleepyHead .
robysue's Beginner's Guide to SleepyHead
03-14-2016 05:43 PM
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Napmeister Offline

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Posts: 74
Joined: Jan 2015

Machine: Resmed S9 Elite
Mask Type: Nasal pillows
Mask Make & Model: Resmed P10 Pillow mask
Humidifier: H5i
CPAP Pressure: testing 10.2 cm
CPAP Software: ResScan SleepyHead

Other Comments: Windows 8.1 64 bit

Sex: Male
Location:

Post: #2
RE: Set CPAP to APAP 90% pressure?
(03-14-2016 05:43 PM)pupcamper Wrote:  I have been running my DreamStation CPAP Pro on auto trial for the last couple of weeks. During that time my 90% pressure has been a steady 10 cmH2O. Is that what my straight CPAP pressure should be set to?

Think that would be a good trial, however, results should be monitored. It's possible to find out you can get away with less but again results should be monitored in case it goes the other way. I had better results at 10.2 than my prescribed 11.0 cm.

If you post results of experiments there are many here that are qualified to suggest improvement settings based on those results.
(This post was last modified: 03-14-2016 06:09 PM by Napmeister.)
03-14-2016 06:06 PM
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JudgeMental Offline

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Posts: 324
Joined: Feb 2012

Machine: Respironics DreamStation Auto-CPAP
Mask Type: Full face mask
Mask Make & Model: Respironics Amara View
Humidifier: Respironics
CPAP Pressure: 11-14
CPAP Software: SleepyHead

Other Comments:

Sex: Male
Location: Florida USA

Post: #3
RE: Set CPAP to APAP 90% pressure?
You may have this knowledge already but I will repeat the definition of the 90% figure for clarification is needed..
"The 90% pressure is defined as the pressure at which the device spent 90% of the time AT or BELOW."
For example, if the device recognized airflow for 10 hours, and 9 of those hours were spent at or below 11cm, and 1 hour was spent above 11cm, then the 90% pressure figure would be 11cm. The unknowns are, how much higher was the pressure for 1 hour and what was the average of the less then 11cm in order to form a base figure. Most people strive to set their "APAP" (not CPAP) pressures to 2-4 cm's below the 90% and 2 or 3 above the 90% in order to accomadate the unknowns.

Yesterday is history; Tomorrow is a mystery; Today is a gift; Thats why its called "The Present".
(This post was last modified: 03-14-2016 06:20 PM by JudgeMental.)
03-14-2016 06:16 PM
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pupcamper Offline

Advisory Members

Posts: 401
Joined: Nov 2015

Machine: PR DreamStation CPAP Pro
Mask Type: Nasal pillows
Mask Make & Model: AirFit P10 Pillows; Quatro Air FFM
Humidifier: DreamStation Heated Humidifier
CPAP Pressure: 10.5 cmH2O; no ramp; no C-Flex
CPAP Software: SleepyHead EncorePro

Other Comments: Lung cancer survivor since 11/2004; CPAP since 11/2015

Sex: Male
Location: Van Buren, Arkansas, USA.

Post: #4
RE: Set CPAP to APAP 90% pressure?
(03-14-2016 06:16 PM)JudgeMental Wrote:  You may have this knowledge already but I will repeat the definition of the 90% figure for clarification is needed..
"The 90% pressure is defined as the pressure at which the device spent 90% of the time AT or BELOW."
For example, if the device recognized airflow for 10 hours, and 9 of those hours were spent at or below 11cm, and 1 hour was spent above 11cm, then the 90% pressure figure would be 11cm. The unknowns are, how much higher was the pressure for 1 hour and what was the average of the less then 11cm in order to form a base figure. Most people strive to set their "APAP" (not CPAP) pressures to 2-4 cm's below the 90% and 2 or 3 above the 90% in order to accomadate the unknowns.

Yes, that is the way I understood the 90%. My AHI had been creeping up so I ran CPCP Check for several weeks. After a while, CPAP Check adjusted my pressure from my prescribed 8cm to 9cm. My AHI dropped some, but not to it's previous level. Out of curiosity I set my machine on Auto Trial. It was a big improvement. My AHI went to below 1 and most nights below .5, with no large leaks. Last night my AHI was 0.0. This afternoon I set the machine back to CPAP Check. I assumed it would still be set on 9cm as it had been when I went to Auto Trial. I thought I would leave it on 9cm and then raise it to 9.5cm if the numbers started creeping up again. It was set on 10cm instead of 9cm when I checked it. That was the reason for my question.

Thanks for the info. I think I will follow my first inclination and set it to 9.5cm and monitor my numbers, possibly slowly raising it until I reach the point of diminishing returns.

"....respiration,—a troublesome practice, but one which custom has rendered necessary to our easy existence...." Oliver Twist, Charles Dickens- 1837

I use FlashPAP to load data from a FlashAir III wifi sd card in my machine to my computer and display it with SleepyHead .
robysue's Beginner's Guide to SleepyHead
03-14-2016 08:07 PM
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