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Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Printable Version

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Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - VisitorX - 07-28-2019

I am experimenting with the Respironics DreamStation vs. Resmed S10 APAP machines, trying to compare how they handle my mixed / complex apnea. I currently use APAP in the range of 8-12 cm.

Though I like the physical design of Resmeds better, and I had always imagined they might be a bit ahead of Respironics technically, I recently found that I was having some very bad nights on the Resmed, worse than on the Respironics. I found that the Resmed fairly quickly cranked the pressure to the top of the APAP range (12 cm, in my case) and kept it there, and the higher pressure made my central apneas worse. At first I thought that the Resmed was responding to my centrals inappropriately, that is, by raising the pressure, which it should not do. But I communicated with someone at Resmed then looked at the clinical manual and learned that when the Resmed algorithm detects two obstructive apneas within a three-minute period, it automatically raises pressure to the top of the APAP range and *holds it there till the end of that sleep session* (i.e., till the machine goes off). 

In contrast, the Respironics seems to respond to the obstructive apneas in a more usual way, raising and then eventually lowering the pressure again. The Resmed approach seems like a bad one, and it certainly caused problems for me. Has anyone else had this experience, or does anyone else have additional insights into the question of Resmed vs. Respironics APAPs for mixed/complex apnea?

Thank you!


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Melman - 07-28-2019

I have a Resmed autoset and it does not behave as you describe. I looked at several nights when I had 2-3 OA in a two min period. The pressure did go up but dropped again after 15-30 min. Can you quote the section of the manual that says it stays at the max until turned off?


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Sleeprider - 07-28-2019

If you are trying to treat complex or central apnea with either machine, you certainly know by now that neither is intended for this therapy. If you need the ASV or Auto SV, then that is what your should pursue. It is pointless to compare the effectiveness of any CPAP in treating complex apnea,..neither is correct. When are you moving to ASV?


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - VisitorX - 07-29-2019

Sleeprider -- thank you for pushing me on this. I needed that shove. Would you be willing to communicate with me by private messenger? 

Melman - thanks for sharing your experience. I just looked in two brochures and could not find what I was looking for. I'm sorry; I can't devote more time to searching right now, though I feel fairly certain about what I referred to -- though for full disclosure I would not have full confidence in it till I located the relevant passage again.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - WhyMe - 07-29-2019

From page 10 of the clinician’s manual:

Minimum pressure (Min. Pressure) that adjusts  according to  the frequency of apneas: If two  apneas  occur within  a  minute, the  pressure reached in response  to  the  second  apnea  will become the  new  minimum  treatment pressure until the next treatment  session.


I assume this is what the OP was referring to - it was all I found that discussed frequency of events in relation to the pressure settings.


Edit:  should point out that this refers specifically to the “for her” mode.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Melman - 07-29-2019

Again, my autoset drops to a lower pressure after two OAs within one minute but it's over two years old and not the for her model. Perhaps they changed the algorithm. It just seems to run counter to the concept of an auto adjusting machine. the critical issue here, as Sleeprider pointed out, is the OP's selection of machines.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Stom - 07-29-2019

(07-28-2019, 05:51 PM)VisitorX Wrote: But I communicated with someone at Resmed then looked at the clinical manual and learned that when the Resmed algorithm detects two obstructive apneas within a three-minute period, it automatically raises pressure to the top of the APAP range and *holds it there till the end of that sleep session* (i.e., till the machine goes off).

That is not correct. Just think about it. If it were true, then under the default 4-20 cm APAP settings just 2 OAs would immediately ramp the pressure up to 20 cm and stay there. That is not how the ResMed algorithm works, and it would be crazy.


This is the OA response for S9 and "S10" Autosets:

Quote:Increases pressure based on current pressure every 10 s of apnea: increment max 3 when pressure is 4. Increment drops linearly down to 0.5 when pressure is 20.

The "For Her" response to OA:
Quote:Increases pressure based on current pressure every 10 s of apnea: increment max 2.5 when pressure is 4. Increment drops linearly down to 0.5 when pressure is 20.

-Treatment of sleep-disordered breathing with positive airway pressure devices: technology update, Medical Devices (Auckland, N.Z.), October 2015
Karin Gardner Johnson, Douglas Clark Johnson


Here is the section from the ResMed Clinical Manual that you misunderstood:
Quote:Minimum pressure (Min. Pressure) that adjusts according to the frequency of apneas:
If two apneas occur within a minute, the pressure reached in response to the second apnea will become the new minimum treatment pressure until the next treatment session.

"[T]he pressure reached in response to the second apnea" is not the max prescription setting, it is based on the increments I noted above.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - VisitorX - 07-29-2019

Storm,

As I read them, you comments do not resolve the issue, for at least two independent reasons. The following response for simplicity applies only to the "him" machine.

First, if I understand your citation scheme correctly, you are quoting from a non-Resmed source that is additionally uncertain because it is dated 2015 and thus may not apply to the current algorithm.

Second, for the sake of discussion, I'll assume that 2015 source is accurate and applies to my machine. For discussion, assume a starting pressure of 12 c.m., which is halfway between 4 and 20 cm. Assuming a linear decrease in the incremental pressure increase down to 0.5 cm at 20 cm, as per your source, this gives an incremental pressure increase (with a starting pressure of 12 cm) of 3 cm + 0.5 cm = 3.5 cm / 2 = 1.75 cm. Now, note that that 1.75 c.m. increase is per 10 seconds of an apnea. Assuming an apnea of 50 seconds, to illustrate, this gives a pressure increase of 50s / 10s = 5; and 5 x 1.75 cm gives a maximum pressure increase of 8.75 cm in response to this apnea.

So, we are now "allowed" in this example a pressure increase of 8.75 c.m. In the case of an APAP range of (to illustrate) 12 cm - 20 cm, this would cause pressure to rise from 12 to 20 cm for the duration of the session, irrespective of how many central apneas and central hypopneas this induced.

I agree with your general comment that it would be "crazy" for the machine to do this (unless Resmed conducted some impossibly massive risk-benefit analysis) but bear in mind that I started exploring this issue because my pressure went from my starting point of 8 cm. to the maximum of 12 cm all at once and stayed there for the duration of my session, inducing many centrals. So, crazy or not, what happened to me seems consistent with my reading of the information you provided.

Again, as per an earlier post in this thread, I am not putting full stock in my original exposition of the algorithm until I can find it clearly stated in the manual (and what you quoted from the manual was not what I saw -- or thought I saw -- which was a simple and unequivocal statement). But the bottom line here is that your post, and the sources you cited, if I am reading all correctly, does not resolve the issue.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Sleeprider - 07-29-2019

In other threads, you have indicated you have complex apnea and you even have an ASV you're not using in ASV mode.

(07-03-2019, 02:11 PM)VisitorX Wrote: First, regarding my machine: DreamStation is my base machine, but I'm currently experimenting with an AirCurve 10 ASV, which for now I'm keeping in the CPAP (not ASV) mode . Once I debug the oximeter, I will see if I can benefit from the ASV function (I have mixed central/obstructive apnea).

 If I make a permanent change in machines, away from my DreamStation, I will update my profile.  As an aside, I'll mention that I also have access to an Autoset 10 -- Resmed's ordinary autotitrating CPAP.

This approach makes no sense at all. If you have complex apnrea, it would help if you posted a chart so we can see the nature of the problem, and if you have ASV, it is the correct technology to treat both the obstructive and central events of complex apnea. If you need help with settings, we can discuss the appropriate settings to start with. It would really help to see charts to understand how your obstructive apnea and central apnea seem to pressure. Why are you not using the ASV?

I do not do private consultations via PM, and prefer any discussions remain on the forum where others can contribute their thoughts or benefit from the discussion. If you have complex apnea then the default settings for ASV are ASVauto mode, EPAP min 4.0, EPAP max 15.0, PS min 3.0, PS max 15.0. CPAP mode is a waste of time, assuming you have already determined that CPAP and APAP do not work.


RE: Question on Resmed vs. Respironics APAP for Complex / Mixed Apnea - Stom - 07-29-2019

(07-29-2019, 06:18 PM)VisitorX Wrote: Storm,

As I read them, you comments do not resolve the issue, for at least two independent reasons. The following response for simplicity applies only to the "him" machine.

First, if I understand your citation scheme correctly, you are quoting from a non-Resmed source that is additionally uncertain because it is dated 2015 and thus may not apply to the current algorithm.

The source I cited is one you can look up yourself. It's an academic paper on the differences in algorithms of various manufacturers. You are unlikely to get this level of detail from talking to a customer service rep or other random person at ResMed. The data I quoted is for the S9 and both the regular Airsense 10 Autoset and the Airsense 10 Autoset 10 "For Her". The Airsense 10 Autoset was released in 2014. There is no reason to think that the algorithms have changed in any major way since the introduction.

(07-29-2019, 06:18 PM)VisitorX Wrote: Second, for the sake of discussion, I'll assume that 2015 source is accurate and applies to my machine. For discussion, assume a starting pressure of 12 c.m., which is halfway between 4 and 20 cm. Assuming a linear decrease in the incremental pressure increase down to 0.5 cm at 20 cm, as per your source, this gives an incremental pressure increase (with a starting pressure of 12 cm) of 3 cm + 0.5 cm = 3.5 cm / 2 = 1.75 cm. Now, note that that 1.75 c.m. increase is per 10 seconds of an apnea. Assuming an apnea of 50 seconds, to illustrate, this gives a pressure increase of 50s / 10s = 5; and 5 x 1.75 cm gives a maximum pressure increase of 8.75 cm in response to this apnea.

So, we are now "allowed" in this example a pressure increase of 8.75 c.m. In the case of an APAP range of (to illustrate) 12 cm - 20 cm, this would cause pressure to rise from 12 to 20 cm for the duration of the session, irrespective of how many central apneas and central hypopneas this induced.

I'm going to ignore your math because the A10 is not for treating complex apnea.

(07-29-2019, 06:18 PM)VisitorX Wrote: Again, as per an earlier post in this thread, I am not putting full stock in my original exposition of the algorithm until I can find it clearly stated in the manual (and what you quoted from the manual was not what I saw -- or thought I saw -- which was a simple and unequivocal statement). But the bottom line here is that your post, and the sources you cited, if I am reading all correctly, does not resolve the issue.

My citation from the Clinical Manual is a cut and paste from the manual.