AVAPS vs Bilevel and which machine is best

I’ve currently been using a Resmed Aircurve 10 Vauto since August 2018. Upon starting treatment I began having high levels of treatment emergent centrals. Thanks to Sleepyhead I can see that I’ve had centrals lasting almost one minute long, back to back with several over 40 seconds long. I also have a neuromuscular disorder and thanks again to Sleepyhead, I know that my tidal volume, respiratory rate and minute ventilation is averaging on the low side.

At the end of October I had another sleep titration to get me on AVAPS therapy. The study was done on a Philips Respironics machine and the ending results showed that I need the setting to keep the tidal volume at 470 or higher also with a backup rate of 12.

Questions:

What’s the difference between Bilevel and AVAPS? I didn’t realize until recently that there is a difference.

Based on the above information which machine is best to treat all that and why? I’m looking at either one of these:

Resmed. https://www.resmed.com/us/en/healthcare ... 0-sta.html
Philips. https://www.usa.philips.com/healthcare/ ... ventilator

Or is there a different machine I should consider?

I’m supposed to be getting the ResMed Aircurve ST-A in about a week, but I’m just still wondering if I should have gone with a machine that specifically has AVAPS on it?

I’m going to post this on a couple different forums because I value the opinions and want to learn all I can.

This video is really good at explaining AVAPS and why it may be used. https://www.youtube.com/watch?v=49hZ8G_r0IM&t=1s

On the Philips Respironics BiPAP AVAPS or DreamStation AVAPS, AVAPS is an additional setting that can be enabled while in the Spontaneous (S), Spontaneous/Timed (S/T) or Pressure Control (PC) modes. I believe only on the actual PR ventilators, such as the A40 or the Trilogy, AVAPS-AE (AVAPS + auto-EPAP) is an independent therapy mode and not just an add on setting.

AVAPS is designed to target an average tidal volume that is programmed by the clinician that supposedly matches the patients ventilation needs. AVAPS stands for average volume assured pressure support. It's designed specifically to treat hypoventilation. What AVAPS does is you set a min and max IPAP, and the machine auto adjusts the IPAP as needed (aka the pressure support since EPAP stays the same as programmed) to maintain the average target tidal volume.

The ResMed iVAPS machine is somewhat similar but its' VAPS algorithm targets alveolar ventilation, taking into account the amount of deadspace (estimated by the patients height) that does NOT contribute to gas exchange. The algorithm in conjunction with a dynamic backup respiratory rate helps maintain a consistent target minute ventilation, even when the respiratory rate changes. Minute volume is the product of RR and Vt, so technically targeting a Vt is only half of the equation.

The ResMed machine is superior in terms of customization settings and build quality, plus the algorithm is much more responsive. However, IMO iVAPS therapy is harder to set up than AVAPS.

Since you were already titrated in the lab using a machine with AVAPS, I would just ask for the DreamStation AVAPS as it seems like they were able to make it work for you. If we were talking CPAP or just your average bipap/bi-level I would recommend ResMed all day. But in your case the machine with AVAPS was already tested on you so I wouldn't want to mess with setting up ResMed on my own, unless they can titrate you on that machine, but who knows the lab could use only PR.

Thanks so much for the response. I stumbled upon that YouTube video about an hour before I posted the question. Those videos showed me how little I know.

I’m used to the ResMed and like the Easy-Breathe technology, so I specifically took my prescription to Apria where I knew I would get a ResMed machine.

But I think you may be right. Based on my lack of knowledge, I didn’t really know the difference in AVAPS until today. Now I’m questioning myself.

I see on your machine information that you use a Respironics AVAPS. Was it harder to get used to? In one of the Youtube videos I watched it said that the volume can go really high if the tidal volume drops too low. Is it a lot different from using an AirCurve vAuto?

I have not used an AVS machine. That said, my DME let me swap from a Dreamstation to an Aircurve when I was having issues adapting from my S9 to a DS. As long as it was within 30 days, they were very cool about it.

The question here: How did you like the product you used in the lab? If it was great, so be it. If it wasn't then we can talk about options.

Again, someone like raisedfist is way better at comparing the two....

LookingUp! wrote: ↑

Mon Dec 10, 2018 9:24 pm

Thanks so much for the response. I stumbled upon that YouTube video about an hour before I posted the question. Those videos showed me how little I know.

I’m used to the ResMed and like the Easy-Breathe technology, so I specifically took my prescription to Apria where I knew I would get a ResMed machine.

But I think you may be right. Based on my lack of knowledge, I didn’t really know the difference in AVAPS until today. Now I’m questioning myself.

I see on your machine information that you use a Respironics AVAPS. Was it harder to get used to? In one of the Youtube videos I watched it said that the volume can go really high if the tidal volume drops too low. Is it a lot different from using an AirCurve vAuto?

Unlike the VAuto machine in VAuto mode, the ST-A and ST machines do not have "EasyBreathe" as an option to enable, only a rise time value to set. Both machines you can adjust rise time. But only on the ResMed can you set a Ti Min and Ti Max or adjust the trigger and cycle settings.

The VAuto mode auto adjusts IPAP and EPAP in order to respond to OSA and things like snoring and flow limitation. The BiPAP AVAPS adjusts to target an average tidal volume so they are quite different from each other.

The AVAPS algorithm is pretty smooth BUT just like when using an APAP, the min pressure is very important to figure out. Where most people screw up AVAPS is they set the min and max IPAP so far apart, basically min 8 and 25 max. Just like people who run their APAP at 4-20 and wonder why their therapy is crap. This can cause huge IPAP changes as say you are at an IPAP of 10 and your volumes are far below the set target, the machine will kick into gear and go from a 1cm h2o per minute increase to a 3cm h2o increase to reach the target volume. I doubt you'd wake up from this, but if this happens while awake it can be uncomfortable and hard to get to sleep.

If you dig into the DreamStation titration protocols, or PowerPoint/PDF lectures or presentations on setting up AVAPS, you begin to learn that it's recommended to set the min IPAP close to or at the therapeutic/prescribed IPAP. Usually then the IPAP mostly just increases during REM sleep so it ends up being more comfortable and you have a nice safety net knowing the machine will raise the pressure a bit when needed to maintain volume.

LookingUp! wrote: ↑

Mon Dec 10, 2018 8:21 pm

What’s the difference between Bilevel and AVAPS? I didn’t realize until recently that there is a difference.

That's like asking "what's the difference in a philips and a screwdriver"

An AVAPS (or iVAPS if you're talking Resmed) is a TYPE of bilevel.

raisedfist wrote: ↑

Mon Dec 10, 2018 8:52 pm

This video is really good at explaining AVAPS and why it may be used. https://www.youtube.com/watch?v=49hZ8G_r0IM&t=1s

And here's info from the other side:
https://www.youtube.com/watch?v=O54vPGx2dKs
https://www.youtube.com/watch?v=nKniYnjMp9c

At this point I'm not sure what to do about knowing the ST-A will be coming in probably within a week. It was special ordered by the DME.

This is the wording on my sleep study:
This AVAPS titration study showed adequate control of OSA and CSA with AVAPS using a Respironics unit with the following settings: EPAP 12cm H2O, IPAP min 17 cm H2O, IPAP max 25 cm H2O, Vtital 470cc, Tinsp 1.5 seconds, rate 12 bpm. A small Simplus interface was used.

Any idea if the ST-A will be the same as far as the EPAP and IPAP settings go? I know on the ResMed there isn't a separate Tidal Volume setting. The machine does that automatically. Hopefully Apria will know how to set the ST-A as close to this as possible.

I often wake up now feeling anywhere from a little bit short of breath to a medium amount short of breath, if that makes sense. When I did the sleep study, the next morning that was no different. I was short of breath about half the day afterward. I remember waking up a very short time in the middle of the night and thinking that the air coming in felt great. I didn't have any issues breathing with the settings they finally arrived at with the Philips Respironics. At this point I don't know if I finally find the right settings on either the ST-A or AVAPS if that will go away and I will actually wake up feeling like I can breathe right.

When I went into my Doctor appointment with my SleepyHead results, showing my AHI anywhere from 20-33 AHI per night, my mind was focused on needing an ASV machine. I remember now the doctor switching over and saying AVAPS but at the time it didn't sink in that he meant a whole different type of study. So my head had been geared to only treating the centrals, not the tidal volume. I didn't know until very recently that a machine could target Tidal volume. And that for some people it is necessary.

Currently my average Median Tidal volume is somewhere between 360-480, Often it's like this as per SleepyHead:
Tidal VolumeAmount of air displaced per breath (ml)
W-Avg: 430.72 0.00 400.00 640.00 1060.00

Palerider, thanks for this analogy "That's like asking "what's the difference in a philips and a screwdriver. An AVAPS (or iVAPS if you're talking Resmed) is a TYPE of bilevel." Obviously I was still not understanding but that makes sense to me. And thanks also for the video recommendations.

TropicalDiver wrote: ↑

Mon Dec 10, 2018 9:51 pm

I have not used an AVS machine. That said, my DME let me swap from a Dreamstation to an Aircurve when I was having issues adapting from my S9 to a DS. As long as it was within 30 days, they were very cool about it.

The question here: How did you like the product you used in the lab? If it was great, so be it. If it wasn't then we can talk about options.

Again, someone like raisedfist is way better at comparing the two....

Thanks TropicalDiver,

I think for me though that Apria only deals with ResMed products unless the doctor is very specific on the prescription that it must be something different. So I don't see them willing to make this switch for me. I wish there was a way I could try both machines and then decide. I've even been watching eBay, Craigslist and eCrater just to see if there is an AVAPS for sale at a reasonable price. So far I haven't found any AVAPS at all on those sites.

LookingUp! wrote: ↑

Tue Dec 11, 2018 1:12 am

This is the wording on my sleep study:
This AVAPS titration study showed adequate control of OSA and CSA with AVAPS using a Respironics unit with the following settings: EPAP 12cm H2O, IPAP min 17 cm H2O, IPAP max 25 cm H2O, Vtital 470cc, Tinsp 1.5 seconds, rate 12 bpm. A small Simplus interface was used.

You actually have a competent sleep lab and sleep physician that has protocols for patients with neuromuscular disease. I would ask for the Philips Respironics machine in this specific case and refuse the ResMed device (as much as it pains me to say that). It's already been dialed in for your needs, it showed evidence of working, and both the lab and your physician are familiar with the machine and how it works. AVAPS algorithm has been around a long time. I would bet a shiny dime that most physicians wouldn't have the faintest clue on how to set up iVAPS.

LookingUp! wrote: Any idea if the ST-A will be the same as far as the EPAP and IPAP settings go? I know on the ResMed there isn't a separate Tidal Volume setting. The machine does that automatically. Hopefully Apria will know how to set the ST-A as close to this as possible.

The answer is 'sort of.' On the ResMed you can set the EPAP and the min and max IPAP (you actually set min and max pressure support). You have to then dial in your height, and your 'spontaneous breathing rate' because it uses that data to calculate your target alveolar ventilation rate. Then you have to figure out what trigger, cycle, and Ti Min and Ti Max settings work best for you. In the case of NMD, it's not just about what is comfortable, but what is actually effective. On the PR, trigger and cycle are automatic (which can be good or bad) and Ti only applies to backup breaths. It's a dumber machine but if it works for you, it works for you.

LookingUp! wrote: I often wake up now feeling anywhere from a little bit short of breath to a medium amount short of breath, if that makes sense. When I did the sleep study, the next morning that was no different. I was short of breath about half the day afterward. I remember waking up a very short time in the middle of the night and thinking that the air coming in felt great. I didn't have any issues breathing with the settings they finally arrived at with the Philips Respironics. At this point I don't know if I finally find the right settings on either the ST-A or AVAPS if that will go away and I will actually wake up feeling like I can breathe right.

The purpose of bi-level PAP in the case of chronic respiratory insufficiency is to prevent hypoventilation, correct blood gasses and rest the breathing muscles. A properly tuned in device will do all those things. It can quite possibly lead to improved activity during the day. Noticeable improvements will probably not happen overnight but within a few weeks or months it is quite possible.

LookingUp! wrote: When I went into my Doctor appointment with my SleepyHead results, showing my AHI anywhere from 20-33 AHI per night, my mind was focused on needing an ASV machine. I remember now the doctor switching over and saying AVAPS but at the time it didn't sink in that he meant a whole different type of study. So my head had been geared to only treating the centrals, not the tidal volume. I didn't know until very recently that a machine could target Tidal volume. And that for some people it is necessary.

A machine targeting tidal volume is not really necessary, it's just a tool that can be of benefit for some people and it prevents the need for most follow up sleep studies, since the IPAP will adjust automatically even with disease progression. You can just as effectively use a machine in the S/T mode, and with enough pressure support, have just as good results with a carefully titrated set up. But if one day you need more IPAP, the S/T mode will not adjust because it can't.

If you have a condition causing profound hypoventilation, the ASV machine would not be a good match. What ASV does is target your own recent minute ventilation to stabilize ventilation and prevent hyperventilation. In the case of NMD, your own recent minute ventilation is inadequate so you definitely don't want a machine that wants to replicate this.

Your central apneas are most likely due to muscle weakness from the NMD, not from CSA. It's a case of cannot breathe, not a case of will not breathe.The backup rate is what treats this.

LookingUp! wrote: ↑

Tue Dec 11, 2018 1:17 am

TropicalDiver wrote: ↑

Mon Dec 10, 2018 9:51 pm

I have not used an AVS machine. That said, my DME let me swap from a Dreamstation to an Aircurve when I was having issues adapting from my S9 to a DS. As long as it was within 30 days, they were very cool about it.

The question here: How did you like the product you used in the lab? If it was great, so be it. If it wasn't then we can talk about options.

Again, someone like raisedfist is way better at comparing the two....

Thanks TropicalDiver,

I think for me though that Apria only deals with ResMed products unless the doctor is very specific on the prescription that it must be something different. So I don't see them willing to make this switch for me. I wish there was a way I could try both machines and then decide. I've even been watching eBay, Craigslist and eCrater just to see if there is an AVAPS for sale at a reasonable price. So far I haven't found any AVAPS at all on those sites.

Tell your physician to specifically write the exact machine and settings they/you want to have. Call Apria and tell them you will only accept this device. If they refuse, find another DME.

A DME must fill a prescription as written just like a pharmacy with a medication.

Thanks for the input. I have a lot to think about. One last question for now.

I was just getting ready to send a MyChart message to my doctor asking for his input. If he wants the DreamStation BiPap AVAPS then to specifically request it on the prescription.

The question is, for that machine, I heard SleepHead isn't available for it yet. Is that correct? So I feel like I would be in the dark as to what's happening and in asking for help. Is that a situation that I should stick with the ResMed instead then? So at least I can post results?

Based on watching the YouTube videos provided on here and doing some reading I'm wondering if either machine is acceptable as long as I'm patient and can get it dialed in right for me.

LookingUp! wrote: ↑

Tue Dec 11, 2018 10:58 am

The question is, for that machine, I heard SleepHead isn't available for it yet. Is that correct? So I feel like I would be in the dark as to what's happening and in asking for help. Is that a situation that I should stick with the ResMed instead then? So at least I can post results?

Based on watching the YouTube videos provided on here and doing some reading I'm wondering if either machine is acceptable as long as I'm patient and can get it dialed in right for me.

I don't think the DreamStation BiPAP AVAPS works with SleepyHead yet, but you can get Encore Pro 2 from Apnea Board for free. It's not nearly as good as SleepyHead, but it does show all the basic data such as leak rate, respiratory rate, tidal volume, AHI data, etc,.

The ResMed ST-A does work well with SleepyHead. The only data that SleepyHead won't show is the alveolar ventilation target reached compared to the goal rate that is set. You need ResScan for that, which is also free on Apnea Board.

Even if the ST-A does work with SleepyHead, this board to my knowledge doesn't have that many people familiar with iVAPS and how to set it up properly. In addition, your physician and sleep lab may not be able to help you either.

I would seriously consider the AVAPS machine because you will need to work closely with your medical team, especially if your NMD is a progressive one and you require follow up. I am not too sure anyone here is qualified to provide that much useful feedback when it comes to non-invasive ventilation.

As an aside, you can always buy a used ResMed S9 VPAP ST-A on the side and tinker around with that. It operates the exact same as the 10 ST-A therapy wise. I've bought one on here before from another user, and they are also for sale at secondwindcpap.

raisedfist wrote: ↑

Tue Dec 11, 2018 1:48 pm

I don't think the DreamStation BiPAP AVAPS works with SleepyHead yet, but you can get Encore Pro 2 from Apnea Board for free. It's not nearly as good as SleepyHead, but it does show all the basic data such as leak rate, respiratory rate, tidal volume, AHI data, etc,.

The ResMed ST-A does work well with SleepyHead. The only data that SleepyHead won't show is the alveolar ventilation target reached compared to the goal rate that is set. You need ResScan for that, which is also free on Apnea Board.

Even if the ST-A does work with SleepyHead, this board to my knowledge doesn't have that many people familiar with iVAPS and how to set it up properly. In addition, your physician and sleep lab may not be able to help you either.

I would seriously consider the AVAPS machine because you will need to work closely with your medical team, especially if your NMD is a progressive one and you require follow up. I am not too sure anyone here is qualified to provide that much useful feedback when it comes to non-invasive ventilation.

As an aside, you can always buy a used ResMed S9 VPAP ST-A on the side and tinker around with that. It operates the exact same as the 10 ST-A therapy wise. I've bought one on here before from another user, and they are also for sale at secondwindcpap.

It's good to know that Encore Pro 2 and ResScan can be used. That makes me feel much better about it even if it isn't as good as SleepyHead.

I also hadn't thought about the fact that my doctor and sleep lab may be unfamiliar with IVAPS and that very few people on the boards might be able to help me. I'm really glad you mentioned it though.

I have already been in contact with Apria last week and on Monday and told them that the ResMed was fine so I'm not sure if I should tell them now that it isn't. But I did send the message to my pulmonary specialist asking him if he would rather I have the DreamStation and if so would he provide a new prescription to Apria stating specifically that's the machine I should get. Most of the time it takes him several days to respond back so I'll wait to see what he says. If it doesn't matter to him, Apria will be giving me the machine that I already told them I would take. I hadn't looked into it enough before talking with them.

Thanks again for the detailed explanations. It has been a really big help. Thanks also for the reassurance that DreamStation is a great machine. ResMed tends to be the most recommended so I really didn't look to far into Philips devices.