Hypothetical question re: typical APAP optimization for OSA based on 2-week data

[Shin Ryoku]

Hypothetically speaking, let's say that all we have to go by initially is the following:

A person with straightforward OSA (no CSA) has been on APAP for two weeks with a Min pressure of 4cm H2O and a Max pressure of 20cm H2O.

The two-week average of their daily median pressure = X

The two-week average of their daily 95th percentile pressure (P95) = Y

Based on those generic data, you have to suggest a new Min and Max that you think will be a significant improvement for them as an initial step towards more optimized settings.

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For example:

New Min = X-2, New Max = Y+2

or

New Min = X-1, New Max = Y

or

New Min = Y-4, New Max = Y + 1

etc

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I'm just thinking of something formulaic as a starting point, pending a closer look at the data.  What would you say?

[Crimson Nape]

In my opinion you will need a formula based on each CPAP brand, since a Resmed responds differently in treating OSA compared to a Philips.

[Shin Ryoku]

In my opinion you will need a formula based on each CPAP brand, since a Resmed responds differently in treating OSA compared to a Philips.

So what would your formula be for a ResMed and a Philips, respectively?


Again, for the sake of this question, please assume that the person in question has plain, uncomplicated OSA with a typical response to APAP and zero CAs on treatment.

[Gideon]

Read this wiki article

http://www.apneaboard.com/wiki/index.php...ng_therapy

Fred

[Shin Ryoku]

Read this wiki article

http://www.apneaboard.com/wiki/index.php...ng_therapy

Fred

Thanks, Fred.  I've read that before and don't personally agree with this part:

"A good rule of thumb is to keep your minimum pressure setting about 2-cm below your 90% pressure or near the average if they are close."

Curious to know what "rule of thumb" others here keep in mind when making suggestions.

[Gideon]

That article also describes and contains links to the titration protocols that sleep clinics use.

[Shin Ryoku]

That article also describes and contains links to the titration protocols that sleep clinics use.

Thank you.  I have read the article in full as well as all of the linked pages and documents.  I've read in full the latest AASM guidelines, the latest ResMed and Philips protocols, and a lot of the medical literature about APAP.

None of that provides a solid evidence base for adjusting APAP Min and Max values.  I am therefore interested to hear expert opinion, ie what folks here tend to keep in mind as "rule of thumb" formulas based on initial APAP median and/or P90/P95 values.

One such opinion is set forth in the article you linked. For example, the article gives examples of Min = P90 - 2 for PR, or Min = Med -2 for ResMed.

A good rule of thumb is to keep your minimum pressure setting about 2-cm below your 90% pressure (PR) or Med Pressure (ResMed) or near the average if they are close. The Dreamstation tends to be conservative with raising pressure, and the algorithm favors returning to the minimum setting. This can often adequately treat OA, but leave you with excessive Hypopnea (H) events. The remedy is an increase in the minimum pressure setting. PR machine: If your 90% setting is 12 cmH2O Min is set to 10 cmH2O and Max Remains at 20 cmH2O ResMed machine: Use the Med value for pressure. If your Med setting is 11 cmH2O, set the minimum to 9 cmH2O and Max remains at 20 cmH2O.

But I am guessing that not everyone uses that approach.  Others likely have different rule of thumb formulas they tend to keep in mind.

Anyone willing to share theirs? I'll share mine:

Given person with straightforward OSA (no CAs either on diagnostic study or while on APAP) has been on APAP for two weeks with a Min pressure of 4cm H2O and a Max pressure of 20cm H2O.

The two-week average of their daily median pressure = X

The two-week average of their daily 90th or 95th percentile pressure (P90/P95) = Y

My approach to initial adjustment would typically be as follows:

New Min = X-2 or 5, whichever is higher

New Max = Y+2 or 20, whichever is lower

That is regardless of whether they were using a ResMed or Respironics device and with the understanding that further adjustments would be made based on response.

[Walla Walla]

Why bother. You'll just disagree.

[OpalRose]

Shin,
This Wiki article http://www.apneaboard.com/wiki/index.php...ng_therapy is an excellent starting point for members to use to optimize their own therapy settings.

I realize from your original post, you are seeking a "Generic" answer from forum members on what "rule of thumb" they might use to advise folk.  Here is where I stand on this subject:
We don't give out "Generic" answers here.  There is no ONE SIZE FITS ALL.  

When advising someone on pressure changes, there are several factors to consider.  We ask them to post data so that we can make the best determination on what direction to take.  I believe a good rule of thumb is the one stated in the Wiki article, but there are many variables to consider before making recommendations, such as how long have they been on therapy, how long have they been on the same pressure settings, what the total AHI is, what the breakdown of AHI is, comfort settings such as EPR and do they have any other medical issues that would come into play?  

There may be instances where a person has Complex Apnea, or mainly Clear Airways.  In that case, we would "not" recommend anyone to raise their pressure.  Sometimes in those cases, we might suggest a Straight CPAP setting based on what is seen in the data.  

You see, we don't give "Generic" answers here.  Each person is an individual and the recommendation would never be the same.

[Shin Ryoku]

The medical literature is particularly conservative / stingy with practical advice, as tends to be the case when an evidence base is lacking. For example, see this recent article written by two physician experts in the field on this topic, see this: https://www.uptodate.com/contents/mode-s...lay_rank=4

Note that they have no specific suggestions about how to determine an APAP range other than this:

For those patients who have residual symptoms and/or snoring, a residual AHIFlow >10 events per hour, a normal leak profile and data to suggest they frequently reach the maximum of the APAP pressure range, we typically empirically increase the top of the pressure range (eg, initial pressure range of 8 to 14 cm H20 would change to 8 to 16 cm H2O) and re-evaluate the patient's symptoms and adherence data in two to four weeks. Issues regarding mask fit and reasons for poor response are also assessed.