Time to upgrade from S9 VPAP Auto - technical questions

McSleepy · Post by **McSleepy** » Fri Aug 24, 2018 6:07 pm

I've had my ResMed S9 VPAP Auto for the requisite three years plus 13 months that the insurance (and my local DME) consider long enough to pay for a new one. (Side note: an insurance phone rep told me the doctor will want to order a sleep study

) Anyway, I was hoping someone knowledgeable will save me the effort to go through full research identifying the next step. The natural progression would be the AirCurve 10 VAuto, but I wanted to hear whether there might be other options. My main issue with other machines has been the lack of adjustability; in the S9 (and S8 before that), I had the ability to set some pressure rate parameters (Ti Min/Max durations, cycle/trigger sensitivity, etc.) but most importantly the rise time. Other machines (e.g., Respironics System One) simply did not work for me, so my next machine would have to have this or similar adjustability. I will eventually obtain the clinician manual for whichever machine is the candidate, but I hope someone will know this and let me know: are there any other machines with similar characteristics/capabilities, and does the AirCurve 10 VAuto have this annoying drawback, like he S9, to not offer adjustability of the rise time when in auto mode? Because of the latter, I have not been able to use it in auto mode, which is not a big deal, but I'd like to have that option. If anyone is curious as to why I'm so sensitive to the rate of pressure increase, it has something to do with my nasal passages, because when I tried briefly to use an oral mask, I did just fine on much lower pressure and with the lower default rise time of the auto mode. I just can't quite get used to the oral mask for other reasons.

McSleepy

Fetou · Post by **Fetou** » Fri Aug 24, 2018 6:34 pm

McSleepy wrote: ↑
Fri Aug 24, 2018 6:07 pm
I've had my ResMed S9 VPAP Auto for the requisite three years plus 13 months that the insurance (and my local DME) consider long enough to pay for a new one. (Side note: an insurance phone rep told me the doctor will want to order a sleep study ) Anyway, I was hoping someone knowledgeable will save me the effort to go through full research identifying the next step. The natural progression would be the AirCurve 10 VAuto, but I wanted to hear whether there might be other options. My main issue with other machines has been the lack of adjustability; in the S9 (and S8 before that), I had the ability to set some pressure rate parameters (Ti Min/Max durations, cycle/trigger sensitivity, etc.) but most importantly the rise time. Other machines (e.g., Respironics System One) simply did not work for me, so my next machine would have to have this or similar adjustability. I will eventually obtain the clinician manual for whichever machine is the candidate, but I hope someone will know this and let me know: are there any other machines with similar characteristics/capabilities, and does the AirCurve 10 VAuto have this annoying drawback, like he S9, to not offer adjustability of the rise time when in auto mode? Because of the latter, I have not been able to use it in auto mode, which is not a big deal, but I'd like to have that option. If anyone is curious as to why I'm so sensitive to the rate of pressure increase, it has something to do with my nasal passages, because when I tried briefly to use an oral mask, I did just fine on much lower pressure and with the lower default rise time of the auto mode. I just can't quite get used to the oral mask for other reasons.

McSleepy

The "EasyBreathe" algorithm that controls the rise time is mandatory in auto mode on the VAuto. You can adjust the rise time in the fixed "S" mode.

Pugsy · Post by **Pugsy** » Fri Aug 24, 2018 7:41 pm

You are going to want to stay with ResMed and go with the newer model the AirCurve 10 VAuto.
You don't want to be changing brands or models. Essentially the same thing as the S9 VPAP Auto but in a different package and a couple additional minor feature additions.
Same algorithm and the basic guts of how it does its job.

palerider · Post by **palerider** » Fri Aug 24, 2018 7:47 pm

You don't like EasyBreathe? I *LOVE* EasyBreathe! Makes me feel like my PS of 6 is non-existent... it's almost like breathing without the mask.

McSleepy · Post by **McSleepy** » Sat Aug 25, 2018 9:27 am

Thanks, Pugsy! Could you elaborate on the feature additions in the AirCurve 10? I may need some arguments to convince the sleep doctor for the new prescription. I'll go get the manual now.

No, I don't like EasyBreathe - for some reason anything other than a violent 100ms (virtually instantaneous) rise from ~15 to ~21 cm H2O makes me feel like I can't inhale and I can't fall asleep or I wake up.

I also don't like how the auto-mode settings are strucutured - you have to start at the lowest pressure! I understand that most people have a problem with the high pressures (hence the ramps, etc.) but since day 1 I've only had problems with low pressure; actually, with insufficient airflow, but the only way I can get enough flow is to have high pressure. In fact, that's the main reason why my pressures are so high. I wonder if it may be worth it trying to retrain myself, but I don't know that the auto mode will have any advantages for me. AHI is not my problem currently; waking up is. I think I may also have UARS.

McSleepy

Jay Aitchsee · Post by **Jay Aitchsee** » Sat Aug 25, 2018 12:03 pm

I dunno, If there isn't anything wrong with your S9, you might want to wait a while before trading it in. The Airsense line was introduced in 2014, I believe, and ResMed has introduced new models about every 5 years, or so. It is my understanding that there really isn't much difference, operationally, between the S9 and the Airsense - mainly external packaging. A comparison of the two clinician's manuals should point up any differences.
Note the qualifiers I believe, or so, and my understanding in the forgoing. Perhaps someone else could add a little more certainty.

StuUnderPressure · Post by **StuUnderPressure** » Sat Aug 25, 2018 3:10 pm

I currently use the AirCurve 10 VAuto & I love it.
Have been on it for just under 1 year.

But, I jumped from the S9 AutoSet to the AirCurve 10 VAuto.

I tend to side with Jay.
I would wait for the next version.
However, there are no guarantees as to when that might come out - so, if you can't live with the S9, you may not have any choice.

Holden4th · Post by **Holden4th** » Sun Aug 26, 2018 2:30 am

I upgraded from the S9 VPAP to the Aircurve mainly to have a back up machine with the same algorithm. I wasn't expecting any changes but I saw a significant improvement using the Aircurve. I also thought that the differences between the two machines were basically cosmetic with the a couple of minor features thrown in. The big plus is having just one hose whether or not you are using the humidifier. It's possible that Resmed tweaked the algorithm but none of their promotional material says that.

As far as another version goes, unless there is a big breakthrough regarding algorithms, it might be a while. The bottom line is that the Aircurve works very well so why not get one.

McSleepy · Post by **McSleepy** » Sun Aug 26, 2018 2:47 pm

Thanks guys! You're making some good points here. The main reason I'm looking to replace the machine is economic: if the insurance will pay (and it's 100% for me, effectively), why not get one? If my current machine wears out or breaks, the policy of the insurance is "you own it, you pay for repairs". But if they will pay for new one, why not get a new one? Of course, I'd also want it to have some advantages. Case in point, when I got the S9, it had "auto" mode while my S8 was a straight bi-level. I have the manual for the A10 and it appears to be exactly the same as the S9. In fact, one surprising difference is specifically in the parameter that matters to me - rise time - and it is not good: the minimum (i.e., fastest rate) is now 150 ms (and still not available in auto mode), up from the 100 ms of the S9. There is more technical detail in the new manual than the old one. For example, they now disclose the functional location of the main sensors:
.

: S9 vs A10 blower.png (68.54 KiB) Viewed 1170 times

.
Note that the airflow sensor is immediately after the air inlet, and not where the pressure sensor is - at the outlet. Probably good enough, but why not do better. Maybe my professional bias...

Anyway, I'll have to collect some more data and think about this. There is a new sleep doctor in town and I will go and see her; maybe she has some good knowledge to share?

McSleepy

palerider · Post by **palerider** » Sun Aug 26, 2018 3:31 pm

McSleepy wrote: ↑
Sun Aug 26, 2018 2:47 pm
Note that the airflow sensor is immediately after the air inlet, and not where the pressure sensor is - at the outlet. Probably good enough, but why not do better. Maybe my professional bias...

How would putting the flow sensor anywhere else be any 'better'?

The pressure sensor is near the outlet, after the blower, because it measures pressure on the output side.

It doesn't matter where the flow sensor is, the flow is constant throughout the circuit within the machine.

McSleepy · Post by **McSleepy** » Mon Aug 27, 2018 10:51 am

palerider wrote: ↑
Sun Aug 26, 2018 3:31 pm

McSleepy wrote: ↑
Sun Aug 26, 2018 2:47 pm
Note that the airflow sensor is immediately after the air inlet, and not where the pressure sensor is - at the outlet. Probably good enough, but why not do better. Maybe my professional bias...
How would putting the flow sensor anywhere else be any 'better'?

The pressure sensor is near the outlet, after the blower, because it measures pressure on the output side.

It doesn't matter where the flow sensor is, the flow is constant throughout the circuit within the machine.

Since air is highly compressible, the momentary air flow is subject to variations with pressure, such as the at transitions from EPAP to IPAP. As long as there are no leaks in the internal path, the overall (long-term average) airflow will be correct, but the momentary will be subject to implicit filtering, such as delays, low-pass, and similar waveform distortions. We (at work) see this in our systems all the time. Now, how significant that is to the intended use (CPAP), it's hard to say, but then again, it's not very difficult to place both sensors at the outlet, either.

MCSleepy

palerider · Post by **palerider** » Mon Aug 27, 2018 12:45 pm

McSleepy wrote: ↑
Mon Aug 27, 2018 10:51 am
variations with pressure, ... Now, how significant that is to the intended use (CPAP), it's hard to say, but then again, it's not very difficult to place both sensors at the outlet, either.

It's easy to Monday morning quarterback when you don't know the design restrictions. The pressure sensor is located at the exit for the reasons you mentioned. If it were important to locate the flow sensor there, and it was practical, then dont you think that resmed would have done so?

McSleepy · Post by **McSleepy** » Mon Aug 27, 2018 6:10 pm

palerider wrote: ↑
Mon Aug 27, 2018 12:45 pm

McSleepy wrote: ↑
Mon Aug 27, 2018 10:51 am
variations with pressure, ... Now, how significant that is to the intended use (CPAP), it's hard to say, but then again, it's not very difficult to place both sensors at the outlet, either.
It's easy to Monday morning quarterback when you don't know the design restrictions. The pressure sensor is located at the exit for the reasons you mentioned. If it were important to locate the flow sensor there, and it was practical, then dont you think that resmed would have done so?

Oh, I didn't realize you had exclusive rights to "Monday morning quarterback"-ing, sorry to encroach!

I know what it takes to build a small, cheap integrated flow/pressure sensor, so whatever restrictions they had were not of an engineering nature. A pressure sensor is so small, compared to a flow sensor, it could have been easily integrated, and flow meters are quite small to begin with; packaging together with much larger components, such as blowers and ducts, is not an issue with those. But, I never said it was any kind of problem; just unlikely to have been difficult to achieve from an engineering perspective, or anything else ultimately of benefit to the user.

McSleepy

Time to upgrade from S9 VPAP Auto - technical questions

Time to upgrade from S9 VPAP Auto - technical questions

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Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

Re: Time to upgrade from S9 VPAP Auto - technical questions

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