S9 Escape Auto (important question)

After a year of CPAP therapy it has come to my attention that my providers in New York City are highly incompetent. When asked about why they ordered for me an Escape Auto vs. an Autoset, they dance around the answer by saying things like "we see from your report you are doing fine". I asked them point blank what advantages the Escape had over the Autoset and of course they had no reply. Also, and this is what really upsets me, what if my report -- which is produced 3 months after i've been on the machine -- HAD shown there was clearly more data required, then what? Would they have admitted -- OOPS, we gave you the wrong machine? Highly unlikely/impossible. They are clearly looking after themselves and the mighty dollar.

But, on to my important question. The S9 clinician manual (which I got through someone on this website -- thank you!) states that for the S9 Escape, "APAP mode treats apneas up to 10 cm H2O and does not differentiate between different types of apneas. The APAP algorithm automatically adjusts pressure in response to inspiratory flow limitation, snore and apnea." For the Autoset it states "The AutoSet algorithm automatically adjusts pressure in response to inspiratory flow limitation, snore and apnea. AutoSet mode offers optional EPR. You can set the minimum and maximum allowable treatment pressures."

So for the APAP mode of the Escape, it "treats" apneas only up to 10 cm H20? I am so confused -- the upper end setting on my Escape auto machine is 20 cm H2O, and my "average pressure" on my machine last night (one of the very few pieces of data available on the Escape) was 11.0 . So what does it mean in the clinician manual that the Escape Auto only treats apneas up to 10 cm H20? Does the Autoset treat them differently?

Separately, I had done some experiments on my own with the APAP 6 months ago to make sure it was working. While awake, I would hold my breath as if I were having an episode and watch to make sure the pressure would go up (my high end setting is set to the maximum). This would work until I got to 10.0 and then, sure enough, i could NOT get it to go higher than 10.0 . I called my incompetent people at the sleep center in NYC and they said it was because above 10.0 it assumes the apneas are central apneas and doesn't go higher....

So to summarize my questions:
A) Is it correct that in APAP mode the Escape only treats up to 10.0?
B) How is it that my average pressure last night was 11.0 in APAP mode (my limits that I assign it are 6.0 on low end and 20.0 on high end) if it only treats apneas up to 10.0 in APAP mode?
C) If this 10.0 max threshold on the Escape is a difference between the S9 Escape Auto and the S9 Autoset, which presumably doesn't have that issue, why hasn't anyone else written about this as an important difference between the two machines? It's more than just the Autoset gives more data!

Thanks you all for your help. Without you I'd have to rely on those incompetent "professionals" at the NYC center....

Short version for the moment until I can find better explanation or Robysue chimes in as she knows the technical details really well.

NYCzzz wrote:A) Is it correct that in APAP mode the Escape only treats up to 10.0?

and (B)

Not entirely. The S9 Escape Auto uses the older A10 algorithm which can't distinguish between centrals and obstructives and while it is commonly thought that it won't increase the pressure past 10 that is not true. It will respond to flow limitations and snores and likely explains why you see it go higher.
The S9 AutoSet uses the new algorithm which uses the FOT to help distinguish between centrals and obstructives and thus it can respond to more than just flow limitations and snores when pressures are past 10.0 and it senses obstructives rather than centrals are occurring.

NYCzzz wrote:C) If this 10.0 max threshold on the Escape is a difference between the S9 Escape Auto and the S9 Autoset, which presumably doesn't have that issue, why hasn't anyone else written about this as an important difference between the two machines? It's more than just the Autoset gives more data!

We have written about it and often. I think Robysue went into a lot of detail about this difference but I can't find it at the moment. People have to understand the A10 algorithm (used on the S8 and older machines) first and it can be difficult for people to understand this 10.0 pressure thing. Back in 2008 and 2009 lots of discussion about it because that was all we had back then with Resmed machines and a lot of people thought the APAP wouldn't increase past 10.0 which wasn't true. It just wouldn't do it unless it was specifically sensing flow limitations or snores...if it was just sensing apneas it wouldn't because back then it was commonly thought that 10.0 cm pressure was a common trigger point for centrals and ResMed chose to ignore rather than risk triggering.
We had ways of dealing with it though by setting the minimum pressures higher to start with.

But yes...it is more than just the fact that the S9 AutoSet records more efficacy data...it uses the new and improved algorithm which can distinguish between centrals and thus if pressures higher than 10.0 are needed for apneas that are obstructive in nature the machine will go there. Potentially better therapy.
It's not like the S9 Escape Auto's older algorithm totally wouldn't/couldn't do the job. It just had its hands tied a bit with the requirement of FLs and/or snores be present and those warning signs don't always pop up with the appearance of the OAs or hyponeas.

NYCzzz,

I'm sorry to hear about the S9 Escape Auto.

On to your question

NYCzzz wrote: But, on to my important question. The S9 clinician manual (which I got through someone on this website -- thank you!) states that for the S9 Escape, "APAP mode treats apneas up to 10 cm H2O and does not differentiate between different types of apneas. The APAP algorithm automatically adjusts pressure in response to inspiratory flow limitation, snore and apnea." For the Autoset it states "The AutoSet algorithm automatically adjusts pressure in response to inspiratory flow limitation, snore and apnea. AutoSet mode offers optional EPR. You can set the minimum and maximum allowable treatment pressures."

So for the APAP mode of the Escape, it "treats" apneas only up to 10 cm H20? I am so confused -- the upper end setting on my Escape auto machine is 20 cm H2O, and my "average pressure" on my machine last night (one of the very few pieces of data available on the Escape) was 11.0 . So what does it mean in the clinician manual that the Escape Auto only treats apneas up to 10 cm H20? Does the Autoset treat them differently?

Short answser:
The S9 Escape Auto uses the older Auto algorithm from the S8 that was developed before the FOT algorithm was developed for distinguishing between clear airway apneas and obstructive apneas; the S9 AutoSet's Auto algorithm makes full use of the FOT algorithm and that in turn changes a lot about how the S9 AutoSet's Auto algorithm works.

Long answer:
The S8 AutoSet auto algorithm which the S9 Escape Auto uses
This algorithm has no way to distinguish between clear way (central) apneas and obstructive apneas. Hence the S8 algorithm scores As (apneas) but it does not try to label them as OAs or CAs. Because the probability that a person with ordinary OSA will have a significant number of central apneas at a pressure below 10cm is relatively low, the S8 Auto algorithm assumes that all apneas that are recorded below 10cm are obstructive and the machine will increase the pressure when a cluster of 2 or more As happen when the pressure is below 10cm.

While most PAPers do not go on to develop problems with pressure induced central apneas, the risk for developing this problem is much higher at pressures above 10cm. In the S8 algorithm, Resmed made the choice to have the algorithm to record but NOT respond to apneas that occur above 10cm in order to minimize the chance that the machine will inappropriately raise the pressure in a patient who is prone to having pressure induced centrals. The thing about pressure induced centrals is that the more the pressure is raised, the more (central) events there are. And so if the machine starts inappropriately responding to a string of central apneas, the the patient gets trapped in a very bad feedback loop: the centrals trigger a pressure increase which causes more centrals which causes another pressure increase which causes more centrals .... In other words, once the pressure gets sufficiently high, the patient's breathing never stabilizes and the pressure increases make things worse instead of better.

Once the pressure is above 10cm, the S8 algorithm and the S9 Escape Auto will continue to increase pressure in response to flow limitations and snoring, but it will NOT respond to clusters of events by increasing the pressure.

The S9 AutoSet Auto algorithm
The S9 AutoSet's Auto algorithm uses the FOT algorithm to distinguish the between clear airway apneas and obstructive apneas by determining the patency of the upper airway. If the FOT algorithm indicates that the airway is NOT blocked, a CA is scored, the apnea is presumed to be a central apnea, and the machine does NOT increase the pressure. On the other hand, if the FOT algorithm indicates that the airway is blocked, an OA is scored, the apnea is presumed to be an obstructive apnea, and the machine increases the pressure (if the OA is part of a cluster of events).

The FOT algorithm allows the S9 AutoSet to increase pressure in response to OAs that are scored when the pressure is above 10cm. And the FOT algorithm also allows the S9 AutoSet to NOT increase the pressure in response to CAs that are scored when the pressure is below 10cm. And so when the FOT algorithm is accurately detecting the nature of the apneas, the FOT algorithm allows the S9 AutoSet to react more appropriately to apneas regardless of the pressure at which they happen.

Note, however, the FOT algorithm is not perfect. While the chance that a real OA will be scored as a CA is pretty small, the chance that a real central apnea might be misscored as an OA or H is higher. The reason is simple: A real central apnea occurs when there is no effort to breathe being made and it is possible that the airway can collapse after the central apnea starts. On an in-lab PSG, centrals are scored by looking at the data from the belts around the chest and abdomen; that data determines whether the patient is making an effort to breathe. In the lab they really don't care whether the airway is clear or blocked in a central and they don't try to determine the patency of the airway in centrals.

Separately, I had done some experiments on my own with the APAP 6 months ago to make sure it was working. While awake, I would hold my breath as if I were having an episode and watch to make sure the pressure would go up (my high end setting is set to the maximum). This would work until I got to 10.0 and then, sure enough, i could NOT get it to go higher than 10.0 . I called my incompetent people at the sleep center in NYC and they said it was because above 10.0 it assumes the apneas are central apneas and doesn't go higher....

The incompetent people at your sleep center were actually telling you the truth (for once). Essentially the older S8 Auto algorithm used by the S9 Escape Auto DOES assume that all apneas scored when the pressure is at or above 10cm are centrals, and it doesn't increase the pressure any further.

So to summarize my questions:
A) Is it correct that in APAP mode the Escape only treats up to 10.0?

Yes in terms of treating apneas. No in terms of treating snores and flow limitations.

B) How is it that my average pressure last night was 11.0 in APAP mode (my limits that I assign it are 6.0 on low end and 20.0 on high end) if it only treats apneas up to 10.0 in APAP mode?

The S9 Escape Auto will still respond to snoring and flow limitations after the pressure reaches 10cm. So if you're snoring and the pressure is above 10cm, the machine WILL continue to increase the pressure. If the machine is still detecting flow limited breathing above 10cm, the machine WILL continue to increase the pressure. So if you spend time snoring when the pressure is at 10 cm, the S9 Escape Auto WILL increase the pressure further.

C) If this 10.0 max threshold on the Escape is a difference between the S9 Escape Auto and the S9 Autoset, which presumably doesn't have that issue, why hasn't anyone else written about this as an important difference between the two machines? It's more than just the Autoset gives more data!

It has been written about. It was BIG NEWS on the Resmed web site when the S9 AutoSet was first released. However, when Resmed made the choice to use the older S8 Algorithm in the cheaper S9 Escape Auto, they did not toot their own horn about that decision. But it was buried in the specs for those who knew where to look for the specs on the S9 Escape Auto.

And one more note about the differences between the S9 Escape Auto and the S9 AutoSet.

For reasons only known to Resmed, Resmed made the decision to have the S9 Escape Auto record NO leak data at all.

Editorial comment: The decision to have the S9 Escape Auto NOT recored leak data is even more dumb than using the older S8 Auto algorithm. The S8 Auto algorithm was a state of the art algorithm back when it was developed, but the S8 AutoSet that used it also recorded leak data. Leak data is critically important in trouble shooting a number of different problems newbies can run into. And just as important: When the leaks are at or above 24 L/min for long periods of time, the data recorded by both the S8 Auto algorithm and the S9 AutoSet's Auto algorithm can be seriously compromised in terms of accuracy. And of course, the S9 Escape Auto uses an algorithm that is known to have problems with accuracy of the recorded data in the presence of large leaks, but the S9 Escape Auto has no way of telling you there ARE large leaks present and you need to not assume the data is correct.

thank you, thank you, and thank you. i think i am going to pay out of pocket for the auto set, rather than let my blood continue to boil over the incompetence/misguided incentives of those who ordered me the wrong device...

Thanks to all of you for the info... I managed to convince my sleep center in nyc to exchange my escape auto for an autoset, even after more than 1 year! (I can be very persuasive when armed with facts).

Wow, you're good! You ought to hire yourself out to others here.