ASV Recently Prescribed: Hypopneas Have Returned

Well, here is a short history: my sleep study's PSG gave me the following results:

Diagnostic
AHI (Non REM): 21.6
AHI (REM): 27
SaO2 nadir: 90%
All Hypopneas

CPAP
AHI (Non REM): 11.84
AHI (REM): 8.47
SaO2 Nadir: 89%
Again, hypopneas

Bipap
AHI (Non REM): 0
AHI (REM): 0
SaO2 Nadir: 94%

So, that seems to be a "happily ever after ending", but a month later, with an at home AHI ranging from 7 - 11 (where 90% of these consisted of Clear Airway Events). Occasionally I would feel lucky to have 7, or less, but noticed increased brain fog. I, just as most folks, dislike brain fog... a lot. Nuvigil was not helping at this point. My doctor listened to me, and prescribed my System One Bipap ASV.

ASV Settings
Night One:
Epap min = Epap Max = 9,
PS min = 1,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 12 (since myaverage bpm 13.5 or so).

Night one yielded an AHI of 6.1 or so. This was a noteworthy improvement, but what is this... sleepy head tells me that my Hypopnea Index (HI) increased to a whopping 4.61.

Being who I am I gradually tweaked parameters to "streamline" or optimize my treatment. I looked for titration algorithms and read some useful comments on this forum (notably papernanny and brianintn had logs), and gave consideration to a few ranges. These tweaks were made like this:

Night two:
Epap min =9,
Epap Max = 11,
PS min = 1,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 13
I obtained an AHI of 2.49!!!!
I felt AWESOME, better than I had in a long while.

Night three:
Epap min =9,
Epap Max = 11,
PS min = 3,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 12
I obtained an AHI of 2.45!!!! I more felt AWESOME. The logic: raise the PS min to reduce the hunt and peck.

On the fourth night I raised PS min = 4, and the AHI increased to 4.99.

Notes:
1) keeping the PS min = 3 is probably a good idea.
2) the central component of the AHI is now <1.

Question:
1) Do EPAP or IPAP take care of Hypopneas more effectively? (yes, I realize that both have a role, but which would be more crucial?)

Disclaimer: I'm not whining about an AHI of 2.5 that is the best I have done in months... I'm just attempting to understand, post my results, and "streamline" this. I also realize that I should contact my doctor again about my changes to the pressures (doctor lives far out of town and is busy). So, thoughts, ideas, advice, etc are welcome.

Bipap Background
So, this either verifies that I the bipap may have been overtitrated, as my pressure was 15/11. Later the Dr. Prescribed 15/10 to "see if some of those centrals clear up". At 15/10 I felt FAR worse... AHI went from 7 + or - 2 to 9 + or minus 2. So, this led to prescription of the ASV. During the 3 week wait for insurance and delivery I felt progressively worse, and attempted to feel better with minor manipulations within the intervals between prescriptions. None of that was helping.

To keep congestion at bay I use a neti rinse.

I will probably post my sleepyhead, but for some reason the pressures seem to be multiplied by a factor of ten for the ASV, while all else seems to be reliable. There were no such problems for the Bipap Auto, but then I also didn't feel rested in the morning.

RationalEntropy wrote:I will probably post my sleepyhead, but for some reason the pressures seem to be multiplied by a factor of ten for the ASV, while all else seems to be reliable. There were no such problems for the Bipap Auto, but then I also didn't feel rested in the morning.

If SleepyHead is reporting the wrong pressure I would suggest bringing this to Jedimark's attention. ASV data is newly added and maybe a little setting or wording in the code is off.

I would suggest waiting at least a week between pressure changes. Give yourself time to get used to the new settings.
I think EPAP and IPAP probably have an equal role is treating OSA. DR. Rapoport says the EPAP should not be lower than your prescribed CPAP pressure, or the lower number for Bilevel. Good luck. It sounds like you are doing a good job.

RationalEntropy wrote:... Night three:
Epap min =9,
Epap Max = 11,
PS min = 3,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 12
I obtained an AHI of 2.45!!!! I more felt AWESOME. The logic: raise the PS min to reduce the hunt and peck....

I would stay with these parameters for a while. You will see some natural variation throughout a week or so.

Some thoughts on your numbers.

Your prescribed pressure is EPAP min and max of 9. That's only only pressure. By setting the max a little higher, you allow it to be a little more responsive to obstructive apneas that might not be cleared by the pressure of 9. EPAP essentially clears the obstructive component of complex sleep apnea. The IPAP [ which is the combination of the current EPAP and the current Pressure Support (PS) ] helps address the central sleep apnea.

Normally the titration protocol recommend starting the PS at a minimum of 3. I find it a little easier to breathe with a PS of 4. But that's me - and probably a due to my extreme obesity.

The PS max of 10 means that the IPAP will not be more than 10cm H2O over the current EPAP. This is needed to help sustain breathing (by acting as a ventilator when you experience a central apnea or experience hypoventilation). Of course, even though PSmax of 10 plus EPAP max of 11 is 21cm H2O, the IPAP max is throttled at 20. I suspect the sleep study found that you experience a significant number of central apneas above a pressure of 20cm H2O.

In your shoes, I would come back to this setting and let things settle out for a while. Remember that your body will be adjusting to this therapy. As you've noted, due to the way that ASV adapts to your breathing, it is *not* like CPAP or BiPAP therapy. It takes a while for you and your machine to get used to one another. Of course, you will be doing most of the adjusting!! But you should find that you will start to sleep more soundly and effectively with this therapy.

RationalEntropy wrote:... Question: Do EPAP or IPAP take care of Hypopneas more effectively? (yes, I realize that both have a role, but which would be more crucial?) ...

EPAP has more of an impact on Hypopneas and Obstructive Sleep Apneas. IPAP (via PS) is sets the limits on the ventilation pressure needed to help support your breathing during hypoventilation and/or central sleep apneas.

RationalEntropy wrote:... I also realize that I should contact my doctor again about my changes to the pressures (doctor lives far out of town and is busy). So, thoughts, ideas, advice, etc are welcome. ...

No problem with making changes - as long as you proceed with caution and remember to take your time making the changes. The more you change at one time, the less certain you are of what made the difference in your therapy. And one night is not enough to determine the best option for your therapy.

Once you find something that works for you, you can then inform your doctor of (a) the process you used, (b) how you determined the best options, and (c) the result ... which we hope is that you are sleeping better and feeling better.

Hope this helps.

Needless to say I'm not surprised to see that this is a very helpful community... definitely a knowledgeable group who is very supportive.

Now, last night I changed one parameter last night: EPAP Min = 8, EPAP Max =11, with everything else the same. AHI was 3.1, mostly hypopneas.

I am likely to run with advice regarding not changing parameters. Namely these:
Epap min =9,
Epap Max = 11,
PS min = 3,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 12

At first my AHI consisted entirely of Hypopneas with not pure obstructions or Centrals. The hypopneas were to be reduced through CPAPping. I was titrated initially to 11 was the maximal effective CPAP, but with the AHI mentioned earlier on for CPAP. CPAP was not tolerated... and then BPAP was phased in to 15/11, and the "clear airway apneas began". Now the saga of the ASV.

I was diagnosed with OSA, and when treated had the clear airway apneas when the hypopneas were eliminated. Now the clear airways have all but been eliminated with a few lingering hypopneas. Funny how things work.

I will also notify Sleepyhead's developer, obtain the latest version of Encore, and follow your advice. Thanks again, everyone. I will keep you posted.

NIght 5:
My results were not quite as good. The Sleepyhead screen caps should echo this. Still feel better than with the Bipap... hahaha.

I now have an apnea related album on photobucket here: http://s575.photobucket.com/albums/ss19 ... 20Records/ Password: password1

There I have posted my most recent night, and will post more soon.

Night 5 Parameters:
Epap min =9,
Epap Max = 11,
PS min = 3,
PS Max = 10,
IPAP max = 20,
Ti = 2,
Backup Rate = 12

Night 5 Results:
AHI: 7.03 0.o
5.35 from Hypopneas
1.53 from clear airway.
Flowlimit: 0.15
VSnore: 1.07

Soon the results from other evenings will be listed on this photobucket account.
Duration with Mask seemed to be the whole night (I think that I have the times set up incorrectly, should just cave and obtain Encore)

I just looked at my settings, and found that my EPAP max was actually at 10, changed that back to 11 (this must have been from two days ago with the 3<AHI<4). I am hoping to obtain number like the two best days. On the bright side there were a few more hours of mask time.

RationalEntropy wrote:... Night 5 Results:
AHI: 7.03 0.o
5.35 from Hypopneas
1.53 from clear airway.
Flowlimit: 0.15
VSnore: 1.07 ...

While the numbers might not be quite as good as you would like, you are headed in the right direction. You are sleeping more with the ASV, you feel better than you did with BiPAP and you are narrowing in on what works for you.

Many of us find that with ASV therapy we slowly seem to see a drop in AHI values. I speculate (and it's just that), that our bodies adjust to the therapy and seem to behave better with the therapy. Of course, take away the therapy and chaos reigns once again. Again, this is just based on my experience and not any studies (of which I am aware).

Since the slightly higher AHI score is mostly due to Hypopneas, you probably do feel much better. Usually, hypopneas do not contribute as much to a drop in O2 as the apneas do. So, an AHI with a high hypopnea score is not as bad as it might seem.

Hang in there!

Just so it is known I believe that the EPAP Max was 10 cm H2O only last night and possibly the night before.

I think using the effective parameters should hold, but I was wondering what would happen if I attempted to use EPAP Min: 10 Cm H20 and EPAP Max 11 Cm H2O (11 is what I was titrated to for my EPAP for the Bilevel therapy). The reason for this thought was that changing the EPAP max on the after the first evening seemed to help a lot, and that there are Red dots in all of my sleepy head graphs during the first hour and 45 minutes or so... almost CONSISTENTLY. This indicates snoring, I believe, which would imply obstructive disturbance (I believe). Following this logic I assume that my hypopneas are obstructive. I have also noticed that before the hypopneas occur there seems to be a greater inhalation (about 2 times in some cases).

I realize that there is a good bit of adaptation to be done, but I do think that extending that range to cover obstructive events helped, and wonder if increasing minimum EPAP would help or not (only by .5 - 1 Cm H2O). I should probably just listen to the advice (STAY WITH THE EFFECTIVE PARAMETERS.). Why refine something to death at risk of failure (if it ain't broke, don't fix it.)?

Also, I plan to drop about 20 lbs of excess weight by refining my semi-broken diet, continuing with my weight training, and increasing cardio/conditioning work. If my therapy begins to become less effective with a bit of fat loss, what signs should I look for? For the record I'm a 235 lb 5'10" male who has a large neck, and is reasonably fit. I miss being about 215 (cosmetically), and it probably couldn't hurt the obstructive component of my apnea to drop a little excess fat. Even when I had abdominals at 183-200 my sleep quality was not all that good, but I chalked that up to stress, at the time.

We have success. AHI has been reduced to 0.5 as of last night (one week one day). Quality of life has improved much, and I've not felt this good in a few years. My relationships have improved (friends, family, professional, romantic), my exercise performance is improving again, as is my recovery from exercise. Mask time has also increased from 5 hours-ish to the entire night, and feeling rested. Wow, I had no idea how much I was missing out.

Lessons learned: EPAP range increase did it, and sometimes less is more.

For those who chimed in... your thoughts were greatly appreciated, and I thank you.

Now I am planning further optimization because there is a lot of variation. I have noted that the Average PS is a touch above 3.5 on my best nights (PS 90% is usually >4.0), and that my Min EPAP is somewhere between 9.0 and 10 on these nights. The range of AHI is anywhere between 0.5 and 4.99. Though this is not bad, it could probably be improved. So, for the sake of sanity, and minimizing diminishing returns these values should only be increased very slowly. The only thing being varied will be the PS. My absolutely best night had an average PS of 4.1, and 90% PS of 4.7, with MAX PS reaching 9.9.

When I am again below 220lbs (probably 1.5 months away) I may have to change the machine's parameters, so that will eventually be noted in a thread of it's own. It should probably be noted that each person is a case study complete with data of varying accuracy. I'm being terrible for not posting every graph, also. Perhaps this should be remedied.

The gradual ASV parameter adjustment with fat loss may be useful for some.

For those wondering: I believe in bf% being a better indicator of health than BMI, but even then that is only one gauge of health. Mainly because I enjoy lifting weights, and have that bias... er, um belief.