Need Help trying to make things "perfect"

[doickle]

I am looking for some help from the forum.
I have been on CPAP for a few months now with good results. Definitely feeling much better than before and daytime sleepiness only occurs occasionally. Overall it is a big win and I am committed to it for the long haul.
I am also about 7 weeks out from a Septoplasty and Turbinate reduction which opened my airway tremedously. This did mess up my AHI for a few weeks but I think I am back in the swing of things now.
So, the purpose of my post is this:
My AHI for the past two weeks has been +/- 2 with the odd night 3 or 4. I want to ask the experts if they can look at my Sleepyhead data and make some suggestions to how I can get below AHI of 1 consistently. I'm sure that I can but I don't quite have the CPAP experience yet to get things dialed in.
Before I post a bunch of screen shots I want to first ask what you need to see specifically to help with this.
I have posted data before but I was wondering if you need more details or specific charts for this type of question.

Let me know and I will post them and hopefully there will be some suggestions from the group.

Thanks

[Gideon]

without question post them, and in this thread.  You had a significant event that could impactyour therapy.  It needs to be looked at, even if it didn't change.

[doickle]

Thanks for the reply.

I'm posting a weeks worth of graphs and on Overall view of my AHI to give a sense of the trend after the surgery.

Any comments, ideas, or analysis is welcome.

[PaulaO2]

Keep in mind, however, that the goal is to keep the AHI below 5. There is not much reason other than you like to fiddle to get it below 1 consistently. True, the lower it is the better, but don't drive yourself insane trying to get it to zero. It is an unrealistic goal. It is more realistic to work to keep it below 3.

There's many on this forum, myself included, who do work to get it as low as possible mostly because we like to fiddle and we're all about the data, 'bout the data, 'bout the data, no guessing.

[doickle]

Keep in mind, however, that the goal is to keep the AHI below 5. There is not much reason other than you like to fiddle to get it below 1 consistently. True, the lower it is the better, but don't drive yourself insane trying to get it to zero. It is an unrealistic goal. It is more realistic to work to keep it below 3.

There's many on this forum, myself included, who do work to get it as low as possible mostly because we like to fiddle and we're all about the data, 'bout the data, 'bout the data, no guessing.

Thanks for the input.
I totally agree and I am very happy with the way my therapy has been going.
However, I am an engineer and looking at the data and fiddling with the numbers is what I do.
I do understand that there will be ups and downs but I would really like to try and minimize the ups and get the down as low as possible.

Thanks

[Gideon]

As I suspected, and as Paula noted, you are doing well.
I did note some minor issues on your chart, they are minor because your numbers are good.  This means you should apply only minor changes.  Keep your current settings for fallback settings.

That said your pressure is being driven by flow limits.  You may want to increase your max pressure a bit.  Note that you are bouncing into your Max 15 of frequently.  As I said small changes, so to Max 16, Don't be surprised to see some recommending higher.  We are NOT trying to make your numbers good, they already are that.

Fred

[Crimson Nape]

doickle,
Your Flow Limit may drive the Resmed to its highest set pressure.  I learned the hard way.  You might consider using the EPR to try to reduce your Flow Limitations. For proof of concept. I'd use the setting of 3.  If you do try it, set the EPR Inhale setting in Options in the Clinical menu to Medium. This will smooth the return to the inhale pressure. The Fast setting is like going from o to 60 in a half second. You can always try it, you might like the blast of pressure.

I'm looking forward to see your results.

[PaulaO2]

Oh! An engineer! Enough said.

And yeah, increase the pressure slightly. Like Goodbye said, try 16 at first. Keep it there for at least a week, hopefully more. Keep track of how you feel, too.

Also consider raising the minimum. You so rarely go near it and the machine has to raise a lot to get to where it needs to be. Take a look at other days and see if you tend to have a Median of 13ish. If you do, then consider raising the minimum to 10.

[doickle]

Thanks all.

I will try these tweaks with the EPR and raising my max and min.
My min is already at 10 but I have it in my profile as 7 as that is where my ramp starts. I will try my min at 11 and max at 16.
Perhaps this is too many changes but if things go bad I will start switching back to current settings in a more stepwise manner.
Another thing I am going to try based on some other threads I have read is getting rid of the ramp. I have had no issues with the mask or any of the therapy so I don't think the ramp is really necessary. I typically fall asleep within minutes anyway.
From all of the comments so far one thing has become obvious, I don't understand Flow Limits.
What is the cause of flow limitations in CPAP therapy and how does it affect the therapy?

Thanks,
Darren

[robysue]

doickle,

I understand that you are an engineer and prone to wanting to make things "perfect".

Before saying anything about your data, I do want to ask you some questions:

1) Since you are feeling good now, what do you want to accomplish by lowering your already acceptably low AHI to the Less than 1.0 range?  Do you think you will actually feel any better? Or is it just for bragging rights?

2) At a certain point, lowering the AHI often requires stuff that can marginally increase comfort problems. And increased comfort problems can lead to poorer sleep even if the numbers look better. So what kinds of adjustment problems did you have?  Are there things that you are simply unwilling to do because you know that they will cause you discomfort?

Having said those things, here's what I think about your data.

Leaks
Most of the time your leaks are under excellent control. Resmed's engineers' Happy Face icon should be showing up night after night.  But there is evidence of some mouth breathing here and there.  In particular, the official Large Leaks on May 8 are probably mouth breathing. And there's probably some mouth breathing May 6 and May 7 as well.  Whether perfecting your leak line by adding a chin strap or cervical collar will improve your AHI or your sleep, however, is an open question.  You may find that the work needed to eliminate the short bits of mouth breathing cause you more discomfort than they are worth.  In other words, if adding a chin strap or soft cervical collar improves your AHI, but at the same time makes it more difficult to get to sleep and to stay asleep, the work to fix the minor leak problem may not be worth doing.


Usage
Overall your usage is quite good. Your usage time ranges from a low of 4:07 to a high of 7:09, with most nights in the roughly 7 hours of usage range.

May 1 is an outlier in your data: On May 1 you took the mask off for good at 2:45AM. I assume you returned to sleep without the mask the rest of that night. However, you are still recovering from surgery and that may have been a factor in the usage that night.

On all the other nights, you have roughly 7 hours of usage, bedtimes are reasonably consistent; you go to bed around 11 to 11:30 every night.  Wake up times are also reasonably consistent: You take turn the machine off between 6:00 and 6:30.  

So there's not much to suggest in terms of improving your usage---as long as you feel like you are sleeping pretty soundly all night long.


The AHI and the pressure range
The current pressure range seems to be good at controlling the obstructive events.  The OAs and Hs that are recorded are usually, but not always, isolated rather than occurring in thick clusters.  There may be a tiny bit of small REM-clusters involving 3-6 events on a few nights, but nothing particularly significant.  However, those possible REM-miniclusters do seem to occur when your machine is maxed out near 15cm.  It could be that you need a smidgeon of an increase in the max pressure.


The RERAs, the flow limitation graph and the pressure range
The most "negative" thing in your data are the consistently ragged flow limitation graphs.  There is a lot of activity in these graphs indicating that your machine thinks it is seeing a lot of flow limited breathing.  Whether those flow limitations represent an airway that is threatening to collapse or just some kind of anomaly in the way your airway is physically put together is a different question.  If the flow limitations are indeed being caused by your airway starting to collapse, then increasing the pressure a bit should smooth out the flow limitation curve.  If, however, the flow limitations are caused by something other than an airway that is starting to collapse, more pressure is unlikely to do much about the flow limitations.  (In my own case, the flow limitations recorded by my PR Dreamstation BiPAP do not decrease with additional pressure, and too much pressure seems to make them get worse.)

Again, since your machine is hanging out right at its max pressure for most of the night, it is possible that an increase in the max pressure may help. But because your minimum pressure is 5cm below your current max pressure, you may find that an increase in your minimum pressure may do more to tame your flow limitation curve than an increase in your max pressure does.  

RERAs are a special type of flow limitation. If you can get the flow limitation graph to be less busy, the number of RERAs should drop.

For many people a modest 1-2 increase in both the minimum and maximum pressure settings doesn't disrupt their sleep or create problems with aerophagia or increase problems with large leaks.  But for a few people, even a modest 1-2 increase in the pressure range does create problems with sleep disruption caused by either aerophagia or additional significant leaks or increased mouth breathing.  So you could try a pressure range that is more like 11-16 or 12-17 instead of your current 10-15 range in an effort to smooth out your flow limitation curve.  Whether the pressure increase needed to smooth out the flow limitation curve is worth it in terms of how you feel (both during the night and during the day) is a different question.


Breathing variability
I'm lumping several things into this overly broad category.  Some of them are reflected in the tidal volume graphs, but mainly they show up directly in the flow rate graph as well.

If you look at the flow rate graphs, you will notice that on every night there are periods where things are nice and flat and the rate of air going into/out of your lungs is almost constant from breath to breath.  This is reflected by the parts of the flow rate that look like a nice flat black bar at the whole-night scale. If you zoomed in to the point where you see individual breaths, the breaths in these parts of the night would look identical to each other: The maxs and the mins would all be at the same heights and the period between the peak of each inhalation would be regular.  In math speak, the flow rate would look sinusoidal. This kind of super regular breathing represents the best of normal non-REM sleep breathing and it usually indicates that you are both really asleep and that the CPAP/APAP is doing its job very well.  The tidal volume graph during these periods of super stable breathing is also almost a horizontal straight line during these parts of the night.

But there are also other parts of your flow rate that look "ragged" even at the whole-night scale. You can tell there's a lot of breath-to-breath variability just by looking at the flow rate. As an example, look at the data from May 1 and the flow rate for 0:45-1:45 (lots of variability) and compare it to the really smooth flow rate 22:45 and 23:15.  Now the raggedy flow rate can mean a lot of different things.  

• Sometimes it just indicates that you might have hit a REM cycle; breathing in REM is less stable than breathing in Stage 2 and Stage 3 sleep.  
  
• Sometimes it means that you've woken up; normal wake breathing is less stable than breathing in Stage 2 and Stage 3 sleep.  
  
• Sometimes it indicates that you are really restless---you've woken up or aroused, but instead of quickly getting back to Stage 2 sleep, you get stuck going back and forth between wake and Stage 1 sleep.
  
• Sometimes it means that you're having a lot of trouble breathing; when people have dense clusters of obstructive events, the flow rate graph gets ragged because after many events you take several "recovery" inhalations that are larger than normal and these large inhalations correspond to the sharp spikes on the whole-night flow rate graph.
  

And it's not particularly easy to tease out what any particular ragged section of the whole-night flow rate graph might be caused by.

In general, if you remember a lot of tossing and turning during the night, much of this more ragged breathing may just be sleep-wake-junk: You're bouncing back and forth between wake and Stage 1 sleep.  Tweaking the PAP settings may not do anything to prevent that. In some circumstances, tweaking the PAP settings may increase the SWJ if you are physically less comfortable after the settings change.

If the ends of ragged breathing bits are spaced at roughly 90 minute intervals and they increase in length as the night goes on, that's indirect evidence that they may just be normal REM breathing. And if there are not any serious clusters of OAs and Hs during those times, then there's nothing to fix because there's nothing wrong.

In other words, tweaking things may or may not make your flow rate curve look any better. And improving the flow rate curve may or may not make you feel any better.

Conclusion
There's no compelling reason in your data that screams increase the pressure or fix the leaks or use the machine all night long.

There is some evidence that it may be worth investigating whether slightly higher pressure settings might help reduce the flow limitations.  And if a slight pressure increase does reduce the flow limitations, it could be that the ragged periods in the flow rate graph will also settle down somewhat.  

So if you really want to tweak things, you could try two separate experiments:

• Increase the minimum pressure to 11cm, and use 11-15 for a few days.
  
• Increase the maximum pressure setting to 16, and use 10-16 for a few days.
  

After a few days, if there's some evidence of improvement, you could then increase the setting that you left alone and try using 11-16 for a couple of weeks.  The AHI may come down. Or not.  The raggedness in the Flow limitation curve may be reduced. Or not.  Leaks may stay under control. Or not.

After a week or two at 11-16, you can reevaluate whether the new setting(s) are better, worse, or about the same as the 10-15 range you are using now.