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90%
#1
even when i read the glossary definition, i really don't understand this factor. i don't use sleepy and my resmed s9 is no help.
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#2
90th percentile, the value that was equaled or exceeded only 10% of the time. Or the value you were at or below 90% of the time. If you were in the 90th percentile in school, 10% of the class was smarter, and 90% achieved less. Still confused? If so, you'd be below the 90th percentile Smile

It refers to statistical distribution. The figure below is a perfectly normal distribution where the mean and median are the same, at the peak of the graph, and all the values from zero to the 90th percentile occupy 90% of the area, and only 10% of the values are above that. If you never did statistics, then chances are, this concept is more difficult.

[Image: 90-percentile1.png]
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#3
Think of it like this: that is the pressure at which you were over for only 10% of the time. The rest (90%) of the time you were below, or at, this pressure. It really only has meaning in relation to your min and max and median and average pressures. For example, if your 90% pressure and your max pressure are the same, that is a suggestion to look at your other stats and detail data and see if an increase in maximum pressure might help.
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#4
A lot of people recommend that the min and max pressure be set 2 cm below and 2 cm above the 90% point, at least I think I got that right. It's chose so when an event happens the machine does not have to "climb" the pressure too much in order to prevent more events. Humm maybe it's just 2 cm below the 90% point and not really related to the high side. Either way the gist of what it is will be the same
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#5
Does the 90% relate to my breathing pattern, or to the designated machine numbers? My S9 is a vpap st, and I use the ST setting, which, as I understand it, compensates for any breathing variance. Also, I wonder how important the 90% data are to me personally? Finally, if I do not make use of Sleepy, how can I even determine the 90% factors? Thanks, and do try to ignore my ignorance.
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#6
CPAP Pressure: 17.8/12.6 is what your machine is set to, your 90% level will be in that range and indicates where you spend 90% of the time at or below the noted pressure. So if your 90% is 16.2 you are spending at or below 16.2 most of the time on CPAP. If you were at 17.6 it would indicate that you might want to consider raising your upper limit above 17.8

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#7
(06-18-2016, 01:01 PM)nativedancer Wrote: My S9 is a vpap st, and I use the ST setting, which, as I understand it, compensates for any breathing variance. Also, I wonder how important the 90% data are to me personally? Finally, if I do not make use of Sleepy, how can I even determine the 90% factors?

Hi nativedancer,

Officially, mathematically, your 90 percentile IPAP pressure was the pressure your mask was at or below at least 90% of the time during the times you were inhaling. It is also the pressure you were at or above at least 10% of the time while inhaling.

Similarly, your 90% EPAP pressure would have been the pressure you were at or below at least 90% of the time while exhaling.

In ST therapy mode, I think when your pressure settings are 17.8/12.6 this means your inhale pressure will be 17.8 cmH2O all night, and your exhale pressure will be 12.6 all night. The difference is 5.2 which is called Pressure Support, the amount the pressure is boosted during inhalation. An ST machine is constantly switching back and forth between EPAP and IPAP in synchronization with your own breathing (or, if you stop, at the backup rate), but the machine does not auto-adjust EPAP or IPAP.

Your machine in ST mode has the backup respiration rate feature, meaning, even if you stop all breathing effort the machine won't stop cycling between EPAP and IPAP. The machine will continue cycling back and forth between 12.6 and 17.8, and when the pressure is 17.8 it will push more air into your lungs and when the pressure drops to 12.6 the air which had been pushed in will exit, keeping some fresh air circulating through your lungs each breath, keeping you perhaps halfway ventilated instead of in complete central apnea. Or, if instead of stopping all effort, if you merely lose about half of your respiratory drive and are exerting about half the effort you normally use when asleep and breathing on your own, perhaps with the machine helping you are getting completely enough air, even when you are providing only about half the breathing effort. Or, if instead of a central event there is an obstructive event, depending on how strong the obstructive event is, there might or might not be any airflow, even though the mask pressure continues to cycle between EPAP and IPAP.

The point is, all night the pressure the machine provided during IPAP was always 17.8 (assuming the Ramp feature wasn't used), and all night the pressure it provided during EPAP was always 12.6 (assuming the Ramp wasn't used).

So the minimum IPAP pressure and the median (50%) IPAP pressure and the 90% IPAP pressure and the max IPAP pressure were all the same, 17.8.

For those who are using bilevel ST mode or bilevel S therapy mode (same as ST mode except without the backup rate feature) or fixed-pressure CPAP therapy mode, the 90% pressure is not of interest. It is significant only to those who are using an auto-adjusting machine.

In an ST machine, it may be significant (or at least interesting) to know what percentage of breaths were patient-triggered (spontaneous) and what percentage of breaths were machine triggered. If all breaths are 100% patient-triggered, perhaps the the backup rate feature is not contributing a benefit (except as a form of insurance; it is there in case it is needed).

Take care,
--- Vaughn
Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#8
(06-17-2016, 02:55 PM)PoolQ Wrote: A lot of people recommend that the min and max pressure be set 2 cm below and 2 cm above the 90% point, at least I think I got that right. It's chose so when an event happens the machine does not have to "climb" the pressure too much in order to prevent more events. Humm maybe it's just 2 cm below the 90% point and not really related to the high side. Either way the gist of what it is will be the same

My 90% pressure for June was 12.20 according to Sleepyhead. So my minimum should be 10.2? Interesting. I have it set to 9 for now.
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#9
(06-19-2016, 08:36 AM)Weird Tolkienish Figure Wrote: My 90% pressure for June was 12.20 according to Sleepyhead. So my minimum should be 10.2?

Hi Tolkienish,

Not necessarily.

A few CPAPers have found they feel most rested when their Min Pressure setting is about as high as their reported 95% pressure or even slightly higher. For example, this might be the case for someone with UARS who is being treated with an APAP instead of a possibly-more-appropriate bilevel machine.

A few other users have found they need to limit their Max Pressure setting very severely in order to avoid terrible aerophagia or in order to avoid huge number of central apneas, or in order to limit pressure on their inner ears or eyes or jaw, perhaps because of dizziness or high intraoccular pressure, or TMJ problems.

Lowering the Max Pressure setting to a pressure reached more than 10% of the night would tend to result in the reported 90% pressure often being the same as the max pressure.

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#10
(06-19-2016, 11:08 AM)vsheline Wrote:
(06-19-2016, 08:36 AM)Weird Tolkienish Figure Wrote: My 90% pressure for June was 12.20 according to Sleepyhead. So my minimum should be 10.2?

Hi Tolkienish,

Not necessarily.

A few CPAPers have found they feel most rested when their Min Pressure setting is about the same as their 95% pressure or even slightly above. For example, this might be the case for someone with UARS who is being treated with an APAP instead of a possibly-more-appropriate bilevel machine.

A few other users have found they need to limit their Max Pressure severely in order to avoid terrible aerophagia or in order to avoid huge number of central apneas, or in order to limit pressure on their inner ears or eyes or jaw.

Lowering the Max Pressure setting to a pressure used more than 10% of the night would tend to result in the 90% pressure becoming the same as the max pressure.

I have about 1 central apnea a night if that.
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