Severity vs. Pressure Prescription

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D.H.
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Severity vs. Pressure Prescription

Post by D.H. » Wed Feb 14, 2018 8:16 pm

It's widely stated prescription has "nothing to do with" how high one's prescription is.

However, I find it hard to accept that there is absolutely no relation.

For instance I would think it's very uncommon that somebody with a "severe sleep apnea" having a prescription of six or less, or somebody with "mild sleep apnea" having a prescription of 12 or more.

Of course, I understand that the correlation is loose. However, I don't believe that is is non-existent.

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Re: Severity vs. Pressure Prescription

Post by TedVPAP » Wed Feb 14, 2018 8:27 pm


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Re: Severity vs. Pressure Prescription

Post by USMCVet » Wed Feb 14, 2018 8:38 pm

Apnea and hypopneas are scored when they last at least 10 seconds. So what if the Mild apnea person has hundreds of ones that last only 9 seconds?

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Julie
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Re: Severity vs. Pressure Prescription

Post by Julie » Wed Feb 14, 2018 9:29 pm

Severity refers to the number of events you had per hour when tested. Even if you had only one, it's possible your personal airway/throat opening is tiny, so you'd need a higher pressure to keep it open, and even if you had 100 events/hr, but a relatively wide airway, you could possibly need only a very low pressure to do the job of keeping it open. Apples and oranges.

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Re: Severity vs. Pressure Prescription

Post by greatunclebill » Wed Feb 14, 2018 9:39 pm

mild and severe are ranges of numbers of events. Pressure is how much pressure it takes to keep your airway open to prevent the individual apneas.

i might have 35 events per hour that requires a pressure of 10 to keep my airway open. you might have 10 events per hours and it takes a pressure of 18 to keep your airway open.

in some cases you are right and in other cases you are wrong. that's about the best i can do here.


was typing as julie posted.

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Bons
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Re: Severity vs. Pressure Prescription

Post by Bons » Wed Feb 14, 2018 10:38 pm

My AHI was 9 prior to treatment. Higher if I was on my back but usually I’m on my side. My epap averages at 14 and my pressure support about 7 so I am at a pressure around 21 most nights. So there you go- mild apnea and very high pressure.

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Re: Severity vs. Pressure Prescription

Post by jnk... » Thu Feb 15, 2018 9:56 am

D.H. wrote:
Wed Feb 14, 2018 8:16 pm
It's widely stated prescription has "nothing to do with" how high one's prescription is.
Did you mean "diagnosed severity," instead of "prescription"? Because the prescription is most certainly related to the prescription. :wink: :)

Most newbies come here with the assumption that knowing someone's pretreatment AHI, which is what doctors generally use to define severity, is directly relevant to knowing how much pressure that person will need to get the best sleep. To many newbies, "severe" means "needs a lot of pressure." That is often one of the first assumptions that needs to be debunked before someone starts to understand the nature of OSA and the nature of the effective treatment of it. The correction being made is a correction of the nature of accepted medical definitions to remind new ones that the definition of OSA severity does not, in the least, take into account how much pressure will be needed to correct sleep-breathing. That is why it is truthfully and accurately explained to them that according to the definitions doctors use, "AHI, what doctors use to define the severity of one's OSA, has nothing to do with how a doctor figures out the prescription of the pressure that will be needed to fix sleep."

So the "nothing to do with" statement often made here is not a statement of relation or association; it is a statement of the nature of the medical definitions that doctors use and that we need to understand to help one another. It is in that sense that "severity has NOTHING to do with pressure." You can have a "mild" condition that requires a high dosage to fix, and you can have a "severe" condition that can be fixed with a very small dose of pressurized air. That is much the same as diagnosing other medical conditions that require drugs. How sick one is does not define how one responds to a particular drug at a particular dose--some respond to certain drugs better than others, which is not something a doc can predict about a particular patient just by knowing how sick the patient is.

Part of the disconnect in all of this is in the fact that AHI isn't even a very good measurement of how disturbed the sleep can be of someone sensitive to changes in his airway. For him, a doctor-defined "mild" condition can be very severe indeed. For the UARS-ish patient with little to no "AHI," he may still need a very high pressure to stabilize his airway sufficiently to allow him to sleep well. That is given only as an example of why doctor-defined "severity" and actual "severity" to a patient can be two very different discussions.

As for the question of the relationship between AHI and treatment pressures, it is best to keep seperate in one's mind the diagnostic process and the titration process. The diagnosis is made to convince payers to allow the opportunity for medical people to see if pressure will help a patient sleep better. Once that proof happens, then the completely separate process of choosing pressure(s) to fix sleep comes into play. Those two processes are directly related only because one has to happen before the other happens. That is the pertinent question of association and causation once one moves out of the realm of the strictly theoretical and into effective treatment, the needs and the results, in my opinion.
Last edited by jnk... on Thu Feb 15, 2018 10:21 am, edited 2 times in total.
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Re: Severity vs. Pressure Prescription

Post by Goofproof » Thu Feb 15, 2018 10:12 am

D.H. wrote:
Wed Feb 14, 2018 8:16 pm
It's widely stated prescription has "nothing to do with" how high one's prescription is.

However, I find it hard to accept that there is absolutely no relation.

For instance I would think it's very uncommon that somebody with a "severe sleep apnea" having a prescription of six or less, or somebody with "mild sleep apnea" having a prescription of 12 or more.

Of course, I understand that the correlation is loose. However, I don't believe that is is non-existent.
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Re: Severity vs. Pressure Prescription

Post by chunkyfrog » Thu Feb 15, 2018 10:23 am

Interestingly, it is not uncommon for a patient to lose weight,
but their required pressure GOES UP.
Not surprised at this nonsense topic---considering the source.

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D.H.
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Re: Severity vs. Pressure Prescription

Post by D.H. » Thu Feb 15, 2018 12:32 pm

Bons wrote:
Wed Feb 14, 2018 10:38 pm
My AHI was 9 prior to treatment. Higher if I was on my back but usually I’m on my side. My epap averages at 14 and my pressure support about 7 so I am at a pressure around 21 most nights. So there you go- mild apnea and very high pressure.
Which machine do you have? Most standard CPAP machines will not go higher than 20. Do you have a "special" machine?

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Re: Severity vs. Pressure Prescription

Post by Pugsy » Thu Feb 15, 2018 4:59 pm

D.H. wrote:
Thu Feb 15, 2018 12:32 pm
Bons wrote:
Wed Feb 14, 2018 10:38 pm
My AHI was 9 prior to treatment. Higher if I was on my back but usually I’m on my side. My epap averages at 14 and my pressure support about 7 so I am at a pressure around 21 most nights. So there you go- mild apnea and very high pressure.
Which machine do you have? Most standard CPAP machines will not go higher than 20. Do you have a "special" machine?
If I remember correctly Bons is using an ASV machine. For sure a bilevel and if I am thinking of the right person it is of the ASV variety.
The link is broken but I think the PR S1 #960.

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Bons
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Re: Severity vs. Pressure Prescription

Post by Bons » Thu Feb 15, 2018 10:04 pm

D.H. wrote:
Thu Feb 15, 2018 12:32 pm
Bons wrote:
Wed Feb 14, 2018 10:38 pm
My AHI was 9 prior to treatment. Higher if I was on my back but usually I’m on my side. My epap averages at 14 and my pressure support about 7 so I am at a pressure around 21 most nights. So there you go- mild apnea and very high pressure.
Which machine do you have? Most standard CPAP machines will not go higher than 20. Do you have a "special" machine?
Yes. I have that special Repironics 960 series ASV that tops out at 25. It’s like sleeping in a wind tunnel when it hits that.

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Re: Severity vs. Pressure Prescription

Post by palerider » Fri Feb 16, 2018 1:17 am

. wrote:
Thu Feb 15, 2018 12:32 pm
Which machine do you have? Most standard CPAP machines will not go higher than 20. Do you have a "special" machine?
Pretty much all bilevels go to 25, some to 30.

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