Bi-pap AVS better for treating UARS?

[gobears]

Been on CPAP with pressure of 8 for 1.5 years now, and feeling better. AHI is low and I generally don't have many apnea/hypopneas. However, I am still not nearly back to 100% again. I went into the sleep lab, and they found I had consistent flow limitations at all pressure levels, up to about 14. At that point, FL decreased but I started getting a few central apneas. They believe I have UARS, with a very mild case of complex apnea. So, now they are going to titrate me on an ASV machine with bi-level pressure. The ASV will help fight the central's at higher pressure, and they also said it would help round out the breathing.

This got me to thinking. I read alot about treating UARS with bi-pap on other threads. In my case, I need Bi-pap + ASV. However, could ASV also be better for those who have pure UARS problems (without the centrals)?

Or, put another way. Assuming cost is not an issue. Would bi-pap + ASV be better than bi-pap for treating UARS? Would the ASV help "round-out" the breathing pattern as Dr. Krakow mentioned?

[dsm]

Bipap is pretty well proven now as a very effective form of cpap therapy. SV added to ipap pressure is designed to round out breathing in people with things like Cheynes-Stokes & Centrals. The extra pressure is *not* good for people who are primarily OSA as the last thing that is needed during an OSA event is a sudden boost in pressure even if limited to 3 CMs over current ipap, within 1 breath.

However, I am one who believes that the SV smoothing is beneficial to those of us who are mild OSA but prone to flow lims, hypops & centrals.

DSM

[rested gal]

gobears, I'm no expert about machines or about treatment. But from what you've described, I think the sleep doctor is going after flies with a cannon, if he's thinking about switching you to an ASV machine for nothing more than this happening:

they found I had consistent flow limitations at all pressure levels, up to about 14. At that point, FL decreased but I started getting a few central apneas.

I'm not trying to trivialize UARS (Upper Airway Resistance Syndrome) which it does sound like you may have. But it doesn't take an ASV machine to treat UARS well. I guess I just don't quite see why they would be thinking of switching from CPAP to ASV at this point.

Anyway, these are the two things that bother me the most, if what you described reflects their thinking...

1. They (the techs/doctor/whomever) seem bound and determined to round out every last flow limitation by using high pressures that you may not really need. High pressures that might, in fact, cause you unnecessary problems (mask issues, aerophagia, etc.) We're not talking apneas/hypopneas -- we're talking "flow limitations" that don't meet the criteria for hypopnea.

Did they say you were getting a significant number of arousals associated WITH most of those flow limitations? RERAs (Respiratory Effort Related Arousals) in significant numbers? That is what would usually earn a person a UARS diagnosis (with or without OSA showing up) to my limited layperson's understanding.

2. I'm also concerned that the appearance of a few centrals at pressure of 14 would make them conclude that you need to use an ASV machine. True, ASV machines are designed to treat central apneas. BUT -- a titration that took you all the way up to a pressure of 14 BEFORE "a few centrals" started popping up, doesn't seem like a good reason to conclude that you are going to have a problem with centrals, nor does it seem to point toward "needing" an ASV machine. New pressures that your body wasn't used to (especially if the titration went upward rather fast) can cause temporary centrals that will subside if the body is given time to adjust to the change in pressure.

Was the entire titration done as a CPAP titration? Or did they, at some point, switch to a bilevel (bipap) titrating?

Was it a split night study (couple of hours of no mask, no cpap at all, just gathering diagnostic data) and then a mask put on you during the night for the titration to begin later in the night?

I'd seriously seek a second opinion outside of that sleep lab about the titration, the diagnosis, and the recommendation to bypass prescribing a regular bipap machine in favor of something as specialized (designed mainly to treat central apneas) as an ASV machine. A few centrals finally appearing at the highest pressure they used in the titration do not mean a machine designed primarily to treat centrals is called for -- imho.

I think you'd find a regular bilevel machine much easier and more comfortable (and probably more effective) for your sleep disordered breathing if what you really have is OSA and/or UARS. From what "you said they said", I think recommending ASV sounds off the wall. There may be a lot more to what turned up in the sleep study and titration though. Seems like second opinion time to me!

[rested gal]

Been on CPAP with pressure of 8 for 1.5 years now, and feeling better. AHI is low and I generally don't have many apnea/hypopneas. However, I am still not nearly back to 100% again.

About that... there can be soooooo many other health issues, or even sleep hygiene issues, that can cause a person to not feel great even if cpap treatment is doing its part of the job perfectly. Just a thought.

[gobears]

Rested Gal,
More information would probably be helpful. I am very new to posting on this site, so not used to giving all the background information that could be useful to the more experienced members, and help get me better feedback. Also, I am not yet fully educated about sleep apnea, UARS, etc... so please forgive me if I am not using the right terminology. I will try to give a clearer picture:

Yes, the flow limitations were RERA's. My AHI without CPAP is around 6.5. With CPAP at a pressure of 8, the AHI goes down very low (< 0.5). However, I still have many RERA's. In fact, my RDI, even with CPAP treatment up to a pressure of 14, remains stubbornly high (> 20), while the AHI portion remains low. And, the RERA's are very disruptive in my case, not allowing me to get much phase 3, phase 4 and REM sleep. There were no other significant disturbances to my sleep. In the next sleep lab visit, they will try pressures above 14 on a Bi-pap, with a much lower pressure for the exhalation phase (probably only need about , to eliminate the RERA's. However, the higher pressure seems to uncover complex apnea. That last part, needs confirmation from the next sleep lab study. So, we will see.... I am not yet convinced I need an ASV either. However, if it can treat some centrals that get uncovered at higher pressures, which I need to treat the UARS, and it also is not otherwise detrimental, then it seems reasonable. That is why I am asking if the ASV Bi-Pap machine is as good for treating UARS as standard Bi-pap, or even better for that matter.

[ozij]

From the data you've added, I think your question should be rephrased, possibly as a number of questions:
Should RERA's be treated? Yes
What happens if an attempt to treat RERA's results in central apneas? That could be an indication of complex sleep apnea, although you may find professional disagreements about the syndrome, some in the profession maintain that the centrals in response to high pressure are temporary, and no longer appear once people get used to them (I think a few weeks were mentioned).
Is an ASV a good treatment machine for complex sleep apnea? Yes. Two companies make them and some people respond well to one company's treatment algorithm, while others respond better to the other one's. The ASV is supposed to be able to maintain your proper flow, without letting central apneas happen.

Does it make sense to start out with a Bi-level (non ASV) titration?
Absolutely
O.

[gobears]

Hi Ozij,
Yes, that is very helpful to break up the questions, and appreciate your answers. There is one more question that was added to the list, which DSM responded.

The question is:
Can ASV added to Bi-PAP (while not neccesarily required), have additional benefits for treating flow limitations in mild OSA cases, or is it rather detrimental? DSM gave his opinion on this:

I am one who believes that the SV smoothing is beneficial to those of us who are mild OSA but prone to flow lims, hypops & centrals

Anybody else have opinions or experience along the same lines, especially in regards to treating RERAs?

[old64mb]

...especially in regards to treating RERAs?

The treatment plan here strikes me as slightly odd.

It certainly sounds like you may have UARS, but also sounds like they haven't confirmed it by measuring pressure differentials. I'll quote Wellpoint: "Upper airway resistance syndrome (UARS) as defined by AHI (or RDI) less than 5/hr but with more than 10 EEG arousals/hr associated with increased respiratory efforts (with or without concomitant observed snoring) and increased negative esophageal pressure (more negative than -10cms H2O).". That part I can understand, since many (most?) sleep labs aren't set up with the equipment (esophageal catheters et al) to do so.

But what I don't quite get is why they're immediately going to the heaviest weapon in their arsenal.

My limited understanding of the step therapy involved for UARS is to really try to get at what's causing your upper airway to compress from a firehose to a straw and try to fix that first. Have you already been on long term pharmacological therapy (nasal steroids etc) to clear up any congestion? If that doesn't work, then have they referred you to an ENT to look at if there's something structurally wrong?

I also wonder how they're going to get an ASV past an insurer; they'll go for a BiPAP since you've "failed" CPAP, but an ASV is in a different league. When you say "higher pressure seems to uncover complex apnea", were you having significant centrals over 14, or from 8 onwards? I'd go back to what RG says about temporary centrals from higher pressures. If you weren't having them until you got to higher pressure, I suspect the insurance company may not agree with the complex apnea diagnosis until you've had a lot longer than two nights to adjust to it. If they don't buy in to it, getting them to pay for the much more expensive machine before you try a BiPAP will be very tough.

[gobears]

The ENT already fixed the nasal issues. They fixed my deviated septum, and also performed a turbinate reduction, with some improvement in air flow. It was never really bad to begin with, but it gave a noticeable improvement. Now, I have very good air flow through the nasal passages. The ENT also examined my tongue, uvula, etc... and did not feel further surgery was necessary.

As for the centrals, I have them at lower pressures too, but they get worse with increasing pressure. I think the next sleep lab visit, scheduled for April, will clarify alot of things. In the mean time, I appreciate very much all the helpful feedback from the forum as it pertains to my personal case. At the same time, I am still eager to learn about AVS technology as it affects flow limitations and the shape of breathing. I read alot of Dr. Krakow's material about trying to get a very natural shape. I am quite certain my doctor will not prescribe AVS unless its necessary for centrals, as its too costly. I don't really care, as long as its fixed. I still have an academic interest in how AVS could benefit / hurt treatment of flow limitations (at this point, please don't take that to mean I am trying to justify one for my case, I am sure the sleep lab will go with the most effective solution). It just seems to me, AVS could help "round-out" the breathing pattern. Just as 2-levels are better than 1 level for this situation, wouldn't 2 levels, with some "adaptive rounding" be even better? Maybe someday the cost will come down and that would become the mainstream solution for treating RERA's.

[old64mb]

As for the centrals, I have them at lower pressures too, but they get worse with increasing pressure.

Ok, with your history it all makes more sense now, since it sounds like you've already been through pretty much everything else and it hasn't worked.

I think you can also see why several of us were somewhat confuzzled; you're swatting at big game rather than flies, so their suggestion of an ASV makes a lot more sense as well (let alone being covered by insurance!)

I too am curious as to what the experts have to say about this as well as what else is out there for RERAs that don't respond to CPAP....

[dsm]

I am happy to further qualify my prior comments by adding that I believe SV is ideal for UARS. If the sleeper is experiencing OSA events & little else, then cpap or bilevel will & should work for them.

If the sleeper is prone to centrals, hypopneas & flow-lims (read UARS), then any device that can detect a flagging volume within 1 breath, and can re target volume within that breath and can adjust pressure instantaneously in an attempt to maintain the target volume,that device has to be beneficial - unless!, the sleeper has some disorder that dictates only gentle pressure rises (COPD patients may need to be careful in the set up of an SV machine).

There are other considerations that come into how effective SV might for particular people (build & lung capacity etc: etc:) but the discussion really gets too specific & becomes a distraction.

The most important thing about SV is that it may be no good for people who are purely OSA sufferers (typically with solid builds & large necks). As mentioned before, if the sleeper is having a typical OSA event above the epap pressure, an SV won't know it is OSA as it works on the principle that epap is dealing with no-flow events and the machine will assume it needs to boost pressure rapidly to maintain target volume.

In future versions of SVs they may add more tests to determine if an apnea experienced above the epap pressure is a no-flow blockage (i.e. by using FOT bursts or some other probing technique). Then based on such a determination, suspend the SV algorithm but perhaps raise epap (I have seen a patent that appears to do this). But today, from what I understand of the technologies available on the market, this type of extension to SV is still experimental.

DSM

#2 Added this link where the authors say they can achieve a high level of accuracy determininga CSA vs OSA events using FOT (goes back to the late 1990s)
http://ieeexplore.ieee.org/Xplore/login ... pdf?temp=x

[gobears]

Thanks DSM!
That was a very informative post, and answers my questions. Now I am well armed with knowledge to discuss with my sleep doctor. Sounds like SV could be a good fit for me, and my sleep doctor is likely on the money with his call. Will let everyone know the results (mid-April).

By the way, I am with Kaiser Permanente, so arguing with insurance about a doctor's recommendation is not an issue.

[dsm]

My prior post got me really thinking hard & remembering the machines that were 'pushing the envelope' with techniques such as FOT. Well it seems what I was calling experimental & the info I saw in a patent on varying Epap to deal with OSA events, is real and not experimental at all, just not in a brand name we are familiar with. The SOMNOvent CR appears to be far more advanced than even the Resmed & Respironics ASV machines.

So, this thread below was created whilst following up on this and other topics.
viewtopic/t39643/Can-cpap-detect-diff-b ... maybe.html

DSM

[gobears]

A brief update: My sleep lab date finally arrived last night! And it could not happen soon enough. Despite using my CPAP religiuously the past months, I have felt pretty worn out.

The sleep lab set me up with a Fisher & Paykell Flexifit 432 full mask. Never used a full mask before. It was surprisingly comfortable. They did a split test, with a few hours of Bi-pap followed by several hours of SV. The bi-pap did not go well. Slept very unsoundly and felt I was fighting the machine. My inhalation breaths kept getting cut short by the sudden switch over. The sleep tech had to do numerous adjustments. I simply could not adjust to it. It was the abrupt switch between IPAP & EPAP and back again. It felt very unnatural and disrupted my breathing patterns.

The SV, on the other hand, felt great! Slept straight through for 4+ hours. The breathing felt very natural.

Anyway, just wanted to capture my experience while its fresh. I will update with the official report later.

[Kiralynx]

They did a split test, with a few hours of Bi-pap followed by several hours of SV. The bi-pap did not go well. Slept very unsoundly and felt I was fighting the machine. My inhalation breaths kept getting cut short by the sudden switch over. The sleep tech had to do numerous adjustments. I simply could not adjust to it. It was the abrupt switch between IPAP & EPAP and back again. It felt very unnatural and disrupted my breathing patterns.

The SV, on the other hand, felt great! Slept straight through for 4+ hours. The breathing felt very natural.

For my titration, I had a mask which worked for me because I'd tried it before. I remember sleeping very badly for part of the titration -- and it was exactly what you said. At one point, the machine seemed to be going faster and faster and faster, and I was hyperventilating, trying to keep up with it.

I don't know if they switched to an ASV, but the tech did some kind of adjustment, and it got better. I have never had that kind of experience since I go my ASV.

Hope you are able to get one, as you slept so well with it. I know it's been great for me.