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

[Shin Ryoku]

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. 

...

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

On the contrary:

1) The Wiki article contains exactly the kind of generic advice I am talking about, so it is not the case that this site lacks generic advice.  Some members go as far as to copy the generic advice from that Wiki to their forum signature. And some even seem to think that generic advice from the Wiki is some sort of evidence-based, established standard. But it is only one version of such generic advice and not an evidence-based one at that. Hence I am curious as to whether different members here have their own such "rules of thumb".

2) I am not looking for one size fits all.  I specifically said "initial step" for a "typical" case of OSA with the stipulation that it was "pending a closer look at the data". I never asked for a "set it and forget it" rule or something that could be used to the exclusion of individual circumstances.

[SuperSleeper]

Note that they have no specific suggestions about how to determine an APAP range...

Nor should they have specific suggestions that should be applied equally to the entire population of APAP users. As Rose said, individualized suggestions based upon many differing criteria (specific to each patient and their data) needs to be taken into consideration.

I think the Wiki article is given as a "starting point" and is only a suggestion to help newbies start the process of CPAP optimization for their specific needs. Ongoing monitoring, data analysis and small "adjustments" over time are going to be the best route for patients who want to take a more active role in their own therapy.

As was said previously, as there is no "One size fits all" advice or suggestion that will work for everyone, neither is there a "typical" case of OSA-- each patient is different. This whole business of CPAP therapy optimization is a process, and cannot easily be defined nor treated using a standardized set of "rules" or a specific "regimen" that can be applied with a broad brush to the majority of patients.

[Shin Ryoku]

Nor should they have specific suggestions that should be applied equally to the entire population of APAP users.  As Rose said, individualized suggestions based upon many differing criteria (specific to each patient and their data) needs to be taken into consideration.

I think the Wiki article is given as a "starting point" and is only a suggestion to help newbies start the process of CPAP optimization for their specific needs. Ongoing monitoring, data analysis and small "adjustments" over time are going to be the best route for patients who want to take a more active role in their own therapy.

We all agree on all of that. I have been plainly clear about as much. This suggestion that I am looking to depersonalize the approach to care is a straw man argument.

I am specifically asking starting point guidance for a typical case of OSA. By "typical", I mean someone who has OSA, does not have any CAs, and does not have comorbid conditions such as COPD, neuromuscular disease, etc. I do not mean that everyone with OSA is the same.

I am asking for something similar to what the Wiki offers. Nothing more or less.

I think the Wiki article is given as a "starting point" and is only a suggestion to help newbies start the process of CPAP optimization for their specific needs.

Let me ask you the same question in a different way.  Do you agree with the "starting point" quoted below as written in the Wiki?  Or would your version of it be different in some manner?

• 6.1 Maximum pressure
  

If the machine reaches the maximum set pressure and stays there for a period of time, this indicates that it is trying to go higher to treat obstructive events. (This applies if your maximum pressure is less than 20. If it is set to 20 and the machine is stuck there, a more detailed analysis is necessary, and a different type of machine may be required). Frequently we see pressure induced CA events. We want to minimize these so we will lower Max Pressure as necessary to accomplish this frequently ending with a very narrow pressure range or even a single fixed pressure.

• 6.2 Minimum pressure
  

If your pressure is too low you are likely to see obstructive apneas and hypopneas. If you notice your average auto pressure is higher than your minimum setting, the hypopnea are likely from the minimum pressure being too low. 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. Note: there is no need to reduce the max unless there is concern over CA events or to minimize the max for comfort at this time. Note that once your titration is complete a good practice is to set the max pressure for just above the max that you normally see, just to prevent “run-away” pressures and leave enough room that you can see your pressure ran higher than you expected.

I can find no examples in the clinical literature of any such starting point guidance, either for clinicians or for patients. At the same time, I think it's great to have something like the Wiki to provide starting point guidance because even a generic starting point is likely to be an improvement on the 4-20 default that so many people are left on, and it provides a step towards more individualized optimization.

My reason for starting this thread is that I think a "starting point" that suggests setting an APAP minimum 2cm H2O below the P90 (or P95) is too aggressive and will result in higher than necessary pressures for a lot of people. It has nothing to do with trying to force everyone's treatment into a cookie cutter approach.

What do you think? Do you agree with the starting point guidance quoted above from the Wiki, or would your version of it be different?

[Crimson Nape]

Shin Ryoku case in point; Due to my flow limitation pattern, if I do not employ the EPR feature on my Resmed, it will sense the limits and keep increasing pressure up to .2cm below the set maximum.  This means that if I don't use EPR then I have to set my CPAP to a straight pressure.  Your theoretical range would be useless for a patient like me without taking flow limitation waveform into account.

[Shin Ryoku]

Shin Ryoku case in point; Due to my flow limitation pattern, if I do not employ the EPR feature on my Resmed, it will sense the limits and keep increasing pressure up to .2cm below the set maximum.  This means that if I don't use EPR then I have to set my CPAP to a straight pressure.  Your theoretical range would be useless for a patient like me without taking flow limitation waveform into account.

I understand that we are all different.  If there were a formula that worked for everyone, the APAP machines would use it, and we wouldn't have to do anything.

Does that mean that the Wiki shouldn't have the starting point advice that it currently contains?  (see Wiki sections 6.1 and 6.2 which I quoted above).

Or is the Wiki-proposed rule of thumb okay as currently written because we all understand that it is just a basic starting point?

And if the Wiki is okay because we all understand that it is just a basic starting point, then do we all agree with the starting point rule of thumb it provides?  Or would some of us propose a different rule of thumb than the one it supplies.

I see that Wiki rule of thumb about APAP Min of 2 less P90/P95 getting cited all over the place and not only on this website. Is it a good rule of thumb as a starting point? That is the question I am asking here.

[Walla Walla]

I can't answer for others. I myself believe the Wiki advice is a good basic starting point.

[kiwii]

Just so you know that Shin is not the only one wondering about this.

I actually came today to ask a similar question, as I am currently unable to post charts and am reduced to figuring it out myself.

The [expletive deleted] sleep doctor announced that I am doing well on 7-13, PS 3 (based on a 90-day average AHI that didn't even show the changes in settings over those 90 days), and that any remaining problems could not be related to sleep apnea. He said that I should consult with my PCP to find out what other issues are causing me to be fatigued and fall asleep in my chair.

Anyway, sorry for being so out of sorts. I'm kind of angry. I don't *do* anger well. But I did want to speak up, that it is not only Shin that is curious about this.

[Shin Ryoku]

Why bother. You'll just disagree.

It's not like I'm claiming to have the best version of a starting point rule of thumb. There are a lot of experienced and knowledgeable folks here, and I'm just polling to see whether the Wiki version reflects general consensus here. It sure gets cited a lot.

I can't answer for others. I myself believe the Wiki advice is a good basic starting point.

Thank you. In retrospect, I could have asked my question in a better way.

Do others agree with Walla Walla about this?

Just so you know that Shin is not the only one wondering about this.

I actually came today to ask a similar question, as I am currently unable to post charts and am reduced to figuring it out myself.

The [expletive deleted] sleep doctor announced that I am doing well on 7-13, PS 3 (based on a 90-day average AHI that didn't even show the changes in settings over those 90 days), and that any remaining problems could not be related to sleep apnea. He said that I should consult with my PCP to find out what other issues are causing me to be fatigued and fall asleep in my chair.

Anyway, sorry for being so out of sorts. I'm kind of angry. I don't *do* anger well. But I did want to speak up, that it is not only Shin that is curious about this.

Thanks, kiwii. I hope you get some answers and feel better soon!

[Gideon]

What do you think?  Do you agree with the starting point guidance quoted above from the Wiki, or would your version of it be different?

The recommendation of "about" 2cm below P90/P95 is listed as a Starting Point in the Wiki article.  Keep in mind that this means your machine is using higher pressures.  The goal is to focus on minimizing the range of pressures for the purpose of minimize the number of apneas that occur.  

In the case you site I would look at the 2 weeks of data you have with the 4-20 range and with your statement of how you feel, to recommend the next steps in helping your treatment.

The article also states to post your charts for analysis.

[Shin Ryoku]

The recommendation of "about" 2cm below P90/P95 is listed as a Starting Point in the Wiki article.

That fact was not lost on me from the outset, and I have acknowledged it a number of times in this thread. In case anyone else thinks I'm interpreting the Wiki rule of thumb as an Ending Point, please be assured that I understand that it is a Starting Point.

Everything I have said in this thread is in reference to a rule of thumb Starting Point.

Keep in mind that this means your machine is using higher pressures.  The goal is to focus on minimizing the range of pressures for the purpose of minimize the number of apneas that occur.  

That's the point that I am questioning. If we want to minimize the range of pressures as much as possible, then we have CPAP. One of the potential benefits of APAP is that in certain scenarios it may facilitate the use of significantly lower pressures than CPAP.

For example, in this crossover-design study showing lesser aerophagia symptoms with APAP than with CPAP, the median pressures on APAP were more than 4 cm H2O lower on APAP than CPAP. The AHI was not significantly different on APAP vs CPAP despite the APAP Min being a full 6 cm H2O less than the average P95 on that therapy.

The P90/P95 is a commonly used Starting Point for CPAP (fixed) therapy.

Using "about" P90/P95 - 2 as a common Starting Point for the APAP Minimum pressure strikes me as too high of a Starting Point minimum. It's giving away a fair amount of the potential of APAP to use significantly lower Starting Point pressures as compared with usual CPAP Starting Point pressures.