ASV vs CPAP - and the winner is...

Well Resmed of course! Yup the authors are ResMed (and one of the commentary authors is associated with both Philips Respironics and ResMed[2]).

The Citation:

Morgenthaler TI, Kuzniar TJ, Wolfe LF, Willes L, McLain WC, Goldberg R. The complex sleep apnea resolution study: a prospective randomized controlled trial of continuous positive airway pressure versus adaptive servoventilation therapy. SLEEP 2014;37(5):927-934 Related article (commentary):833

Things noted while reading the article:

With Complex Sleep Apnea (CompSAS) they seem to be happy to get the AHI below ten (rather than five).

In the study pressures above 15 cm/H2O were excluded (usability?).

In both the ASV and CPAP arms each lost 36% because the participants did not use the machines enough during the three month study. With additional losses (drop outs – 6% on the ASV arm and 3% on the CPAP arm) only 54% completed the study to become part of the “evaluable participants”.

The authors report that their use rates are comparable to those in other studies.

They add “... we were unable to identify any clinical or PSG features that would predict resolution of CompSAS on CPAP. We believe that the analysis of other variables or physiological responses that are not currently collected during typical clinical and PSG evaluation, such as the measurement of apneic threshold, carbon dioxide (CO2) reserve, controller gain, gain margin via measurement of end-tidal CO2, additional dead space, or responses to hyperventilation by conventional bilevel device or proportional assist device may be needed to predict this response[32-34] ”

At 90 days CPAP and ASV had very similar results in terms of usability, total sleep time, sleep efficiency, total arousal index, average daily usage, ESS (daytime sleepiness) index, SAQLI (quality of life) index, and comfort.

However ASV did much better at initially reducing central events and continued to do better regarding these events at 90 days such that total AHI was 9.2 for CPAP and 4.9 for ASV.

[2] Orr J, Javaheri S, Malhotra A. Comparative effectiveness research in complex sleep apnea. SLEEP 2014;37(5):833-834

[32] Salloum A, Rowley JA, Mateika JH, Chowdhuri S. Omran Q, Badr MS, authors. Increased propensity for central apnea in patients with obstructive sleep apnea: effect of nasal continuous positive airway pressure. Am J Respir Crit Care Med, 2010;181:189-93

[33] Younes M, Ostrowski M, Thompson W, Leslie C, Shewckuk W, authors. Chemical control stability in patients with obstructive sleep apnea. Am J Respir Crit Care Med. 2001;163:1181-90

[34] Gilmartin G, McGeehan B, Vigneault K, et al., authors. Treatment of positive airway pressure treatment associated respiratory instability with Enhansed Expiratory Rebreathing Space (EERS). J Clin Sleep Med. 2010;6:529-38

I'm curious what conclusion you are drawing from this. It seems pretty straightforward, to me: ASV, which is designed to treat complex apneas that CPAP/APAP have difficulty treating, seems to treat such complex apneas better than CPAP/APAP. *shrug*

The Latinist wrote:I'm curious what conclusion you are drawing from this. It seems pretty straightforward, to me: ASV, which is designed to treat complex apneas that CPAP/APAP have difficulty treating, seems to treat such complex apneas better than CPAP/APAP. *shrug*

They are only beginning to really look at this.

Basically the only thing that ASV seems to improve over CPAP at 90 days is reducing central events. Usability, quality of life, sleepiness, total arousal index, average daily usage, and perceived comfort are about the same.

Is four times the cost worth that?

Perhaps the reduced vascular change load within the brain from reduced central events is worth that but I think it would take years to find out (for it to show the difference).

Arousal index is identical at 24/h!

When a lot of periodic breathing and “clear airway” events appeared in my life I noticed the arousal event issues and decided to take care of the clear airway events with EERS[34] and stay with CPAP. I am glad I did. I think that I have been thus enabled to heal more and faster with less arousals.

[34] Gilmartin G, McGeehan B, Vigneault K, et al., authors. Treatment of positive airway pressure treatment associated respiratory instability with Enhansed Expiratory Rebreathing Space (EERS). J Clin Sleep Med. 2010;6:529-38

It seems to me that it should be up to the patient and his doctor whether they feel that reducing central apneas justifies the added expense. I don't see anything wrong with ResMed offering the tech as long as they aren't making false representations about it; and since what you are talking about is published research from ResMed, it seems to me that they are being quite honest about it.

I guess it depends on how you feel after a nights rest.
For me the ASV works best!
It's only money you can't take it with you.

What is ASV?

kona0197 wrote:What is ASV?

adaptive servo ventilation (ASV)

Todzo wrote:When a lot of periodic breathing and “clear airway” events appeared in my life I noticed the arousal event issues and decided to take care of the clear airway events with EERS[34] and stay with CPAP. I am glad I did. I think that I have been thus enabled to heal more and faster with less arousals.

[34] Gilmartin G, McGeehan B, Vigneault K, et al., authors. Treatment of positive airway pressure treatment associated respiratory instability with Enhansed Expiratory Rebreathing Space (EERS). J Clin Sleep Med. 2010;6:529-38

Is there a good reference thread where you describe exactly how you went about this? I remember something about using a couple of 2L plastic bottles but not the necessary calculations or methodology, CPAP settings, etc.

SleepWrangler wrote:

Todzo wrote:When a lot of periodic breathing and “clear airway” events appeared in my life I noticed the arousal event issues and decided to take care of the clear airway events with EERS[34] and stay with CPAP. I am glad I did. I think that I have been thus enabled to heal more and faster with less arousals.

[34] Gilmartin G, McGeehan B, Vigneault K, et al., authors. Treatment of positive airway pressure treatment associated respiratory instability with Enhansed Expiratory Rebreathing Space (EERS). J Clin Sleep Med. 2010;6:529-38

Is there a good reference thread where you describe exactly how you went about this? I remember something about using a couple of 2L plastic bottles but not the necessary calculations or methodology, CPAP settings, etc.

The referenced article has a good set of pictures and all which could help a doctor to do this and I certianly do think that anyone with CompSAS should be talking about EERS with their doctor.

Moving and calibrating a vent point is not a hard thing to do although somewhat technical. Water is a great way to determine volume. My doctor at the time agreed that it was a reasonable approach and it worked well for my stress related CPAP emergent hypocapnic central apnea events. It is certainly is a lot cheaper than ASV.

I just had another sleep study. They called me and told me I will be getting an asv machine. Does this relate to what your talking about. What is eers?

Bennnyp wrote:I just had another sleep study. They called me and told me I will be getting an asv machine. Does this relate to what your talking about.

The article talks about a study which looks at ASV vs CPAP treating Complex Sleep Apnea (CompSAS). This is where a person develops Central Sleep Apnea while using CPAP. It tends to be hypocapnic rather than hypercapnic in nature and related to the respiratory control system gain being too high. In other words the pressure of CPAP helping you to breath more tends to reduce the carbon dioxide levels to the point where they go below the apneic threshold and so a hypocapnic (hypo: too little capnic: related to carbon dioxide) central apnea is created.

I do not know your particulars but would strongly encourage you to talk with your doctor about how this relates to your specific situation. In six months the article will be free. However it might well be worth the purchase of it or a subscription to SLEEP.

Bennnyp wrote: What is eers?

When we breath out the very last portion of our breath is very high in carbon dioxide. So it takes only a little of it to allow us to maintain enough carbon dioxide (CO2) reserve to keep our CO2 levels above the apneic threshold.

Most modern CPAP systems use a “lossy mask” to eliminate breathed air and facilitate the breathing of fresh air. Simply they vent the air near the nose or nose/mouth. A typical vent rate might be in the oder of 30 liters per minute, a typical “minute volume” air use rate by a person might be in the oder of 6 liters per minute. During times of heavy breathing the peak rates may exceed the vent rate and a bit of breathed air may back up into the supply tube but most likely it will clear before inspiration begins.

To create an enhanced expiratory rebreathing space (EERS) the vent point is simply moved away from the nose/mouth as necessary to provide the desired amount (see [1] for photographs and details).

Talk with your doctors about [1,2].

[1]: Gilmartin G, McGeehan B, Vigneault K, Daly RW, Manento M, Weiss JW, Thomas RJ.
Treatment of positive airway pressure treatment-associated respiratory instability with enhanced expiratory rebreathing space (EERS).
Source: J Clin Sleep Med. 2010 Dec 15;6(6):529-38. Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Link: http://www.ncbi.nlm.nih.gov/pubmed/21206741

[2]: Dynamic CO2 therapy in periodic breathing: a modeling study to determine optimal timing and dosage regimes
Yoseph Mebrate, Keith Willson, Charlotte H. Manisty, Resham Baruah, Jamil Mayet, Alun D. Hughes, Kim H. Parker and Darrel P. Francis
J Appl Physiol 107:696-706, 2009. First published 23 July 2009; doi: 10.1152/japplphysiol.90308.2008
Link: http://www.ncbi.nlm.nih.gov/pubmed/19628721

letsride wrote:I guess it depends on how you feel after a nights rest.
For me the ASV works best!
It's only money you can't take it with you.

I am glad to hear that it works for you.

I just wish it worked for more of the people in the study.

In my case the ASV machine made a significant difference to how I felt, and to all of the stuff the doctor looked at like blood 02 Levels.

Under CPAP the couldn’t get my AHI below 40 or so and my blood 02 level remained in the 70 percent range during the sleep study under the best pressures they tried me at so they didn’t even prescribe a CPAP for me, they just brought me any for a second titration.
They did try me on a Bipap for 4 months or so, even though at best they could only get my AHI down to the 10 to 20 range with it, and blood 02 levels in the high 80 low 90 range. The sleep doc looked at my trends, how long the apneas were, and in the end went with trying an asv machine rather than try supplemental 02 since my o2 levels were trending down rather than up to the levels he hoped to achieve. With the asv machine my 02 levels have remained mid to high 90’s and my apneas of course well under ahi of 5.

From my perspective, the important part was how I felt during the day. The Bipap made a huge difference, but the results were inconsistent, and not as good as I would have liked. The ASV machine the difference in how I feel isn't as significant as going from no treatment to bipap, but it's noticeable. I will say it admittedly makes it a little harder to sleep some nights, but it results in my feeling consistently good throughout the day making it a very worthwhile improvement, and the stuff the doctor tends to look at all looks pretty good to him as well. As a result the doc and I don’t have to have the debate about supplemental 02 that we had earlier in my treatment.

SeekSleep wrote:In my case the ASV machine made a significant difference to how I felt, and to all of the stuff the doctor looked at like blood 02 Levels.

Under CPAP the couldn’t get my AHI below 40 or so and my blood 02 level remained in the 70 percent range during the sleep study under the best pressures they tried me at so they didn’t even prescribe a CPAP for me, they just brought me any for a second titration.

I am glad it was clear to them on the night tested. I know from my own experience that my tendency toward unstable breathing can change both quickly and dramatically. But the night they tested you they had what they needed to move you toward what you need. That is good!

SeekSleep wrote:They did try me on a Bipap for 4 months or so, even though at best they could only get my AHI down to the 10 to 20 range with it, and blood 02 levels in the high 80 low 90 range.

Yes it from what I read here the way of doing things in our current system is to have the person fail a less expensive treatment to justify the use of a more expensive treatment. I think that is kind of hard on the person needing the treatment.

SeekSleep wrote: The sleep doc looked at my trends, how long the apneas were, and in the end went with trying an asv machine rather than try supplemental 02 since my o2 levels were trending down rather than up to the levels he hoped to achieve. With the asv machine my 02 levels have remained mid to high 90’s and my apneas of course well under ahi of 5.

In the study they do show that the ASV machines work well in terms of getting the numbers to look good.

SeekSleep wrote:From my perspective, the important part was how I felt during the day. The Bipap made a huge difference, but the results were inconsistent, and not as good as I would have liked. The ASV machine the difference in how I feel isn't as significant as going from no treatment to bipap, but it's noticeable.

I very much agree that “feel” (and more measured in my case – performance) is very important and likely more a measure of how the machine is helping us toward health.

SeekSleep wrote: I will say it admittedly makes it a little harder to sleep some nights, but it results in my feeling consistently good throughout the day making it a very worthwhile improvement, and the stuff the doctor tends to look at all looks pretty good to him as well. As a result the doc and I don’t have to have the debate about supplemental 02 that we had earlier in my treatment.

I am very glad to see that they have made a machine which appears to move a person away from hypocapnic central apneas and the associated cerebrovascular impairment. That is good!!!

But apparently dancing the pressure all around to do so causes arousals and fractures sleep as much as the unstable breathing from a normal CPAP would.

I am glad you have a machine which makes you feel better and likely keeps your brain more healthy. I also hope they find a way to get rid of the excessive arousals the machine apparently causes. That will make for a much better day and days.

One of the things I found in this study was reference to the Calgary Sleep Apnea Quality of Life Index (SAQLI)[23].

The quality of life aspects of sleep apnea deserve more consideration.

[23] Flemons WW, Reimer MA. Authors. Development of a disease-specific health related quality of life questionnaire of sleep apnea. Am J Respir Crit Care Med. 1998;158:494-503