[Pressure] Call this good, or keep going?

[SleepingFish]

New user finally over the newb hump. Got my AHI down to 1.98. Do I call it good here, or do I ramp pressure and seek better results?

Hated APAP so turned it off.
Hated EPR so turned it off.

Rocking a steady 8 cmH2o.

So do I go up to 9 or 10, or say 1.98 is a real good for a "low" pressure, call it good and leave it?

[Melman]

AHI of 1.98 is acceptable, especially if your feeling rested. What didn't you like about EPR? Use of EPR would reduce your flow limitations, hypopnea, and RERAs.

[SleepingFish]

AHI of 1.98 is acceptable, especially if your feeling rested. What didn't you like about EPR? Use of EPR would reduce your flow limitations, hypopnea, and RERAs.

1) Physically, I dislike it. It makes you "follow" the machine, it's not really the machine following you. So for example if I roll over and delay a breath by 2 seconds, I am off cycle and suddenly have to push out with a ton of pressure. This almost always wakes me up.

2) I have no problem exhaling at a pressure of 8. I am sure as this rises it can get harder, but once I settle in it feels very natural.

3) Watching youtube videos of Lefty etc, it sounds like a lot of professionals thing EPR is only useful for:
   a) Users which high pressure (16+) that need a BIPAP machine, but only have a CPAP machine
   b) Brand new users getting used to CPAP
But is not actually a good thing to leave on long term.  Since I settled in without it, it would seem a step back to go to EPR. However,

>   reduce your flow limitations, hypopnea, and RERAs.

Those are all things I want to do, so am a bit confused.

Attaching a picture of last night. It seems to be about the same. I was basically perfect midnight - 4am. Will a bit more pressure solve this? I think I need to try it to find out.

Is there no chance that raising my pressure to 9 or 10 would reduce my Hyponeas and RERAS?  That seems a pretty easy thing to try on my end.

[Sleeprider]

I disagree with your conclusions concerning EPR. I have found it is a means of providing bilevel PAP pressure support to users that have a CPAP prescription. This pressure support, when used properly actively mitigates flow limitation/restriction as well as making therapy more comfortable an tolerable to users of all experience levels. There is no correlation between the use of EPR and years of experience in using CPAP. Resmed's EPR is triggered and cycled based on spontaneous respiratory flow, so while you perceive it is leading your respiration, it is actually designed to follow your lead, and that is demonstratable by closely analyzing charts in Oscar. EPR follows Resmed's EasyBreathe™ algorithm, so very little time is actually spent at IPAP. It's pretty clear the majority of a user's respiration will be at pressures below the current setting. This can result in loss of efficacy if pressure is not adjusted upward, or the Autoset algorithm used to ensure the airway remains patent throughout the respiratory cycle.

Your respiratory statistics clearly show the effects of a relatively high flow limitation, not only by the FL 95% statistic of 0.21 and 99% at .44, but also by the relatively long inspiration time of 2.28 seconds, compared to much shorter expiration time of 1.94 seconds. This reflects a lot of inspiratory effort to overcome your upper airway resistance, so breaths are being decapitated for peak flow and are taking longer to meet your tidal volume needs. This is the birthplace of RERA and hypopnea that we see in your charts. Your flow chart shows many spikes in flow as recovery breaths and arousals are likely occurring. In addition, you are using fixed pressure because the Autoset algorithm would otherwise increase pressure to treat these flow limits, so while your pressure of 8.0 is satisfactory for preventing OA events, it is not able to address any increases in obstructive flow. A zoomed view of your flow rate would show these problems are relatively severe compared to most of our members here whom have used EPR to mitigate this problem. Our wiki shows an example of flow limitation without and with EPR http://www.apneaboard.com/wiki/index.php...limitation

You are practically the poster child for why we recommend EPR, and while it may take some time to become accustomed to the pressure support, I think in the long run you would find it more comfortable and effective if you start gradually with EPR at 1 and increase as you tolerate it. My suggestion would be to start in Autoset mode with minimum pressure 8.0, maximum pressure 10.0 and EPR 1 and eventually move towards a pressure range of 10.0-14.0 with EPR 3, but move at a pace that works for you.

[Crimson Nape]

Looking at your Flow Limits, show it running a little high.  Because of this, you would benefit from employing the EPR feature.  Since you seem to not like it, you might try starting at a setting of "1" to see if your Flow Limit is reduced enough.  Two caveats about using EPR.  Since the EPR is subtracted from your IPAP pressure, you need to increase your minimum pressure by the EPR's value to make up for this.  The reasoning behind this is your EPAP (exhale pressure) controls the OAs and Hypopneas.  The second is the use of EPR can wash out your CO₂, thus causing CAs.  Usually, as your body adapts to the lower CO₂ levels, the CAs will start to diminish.

Now, your Hypopneas; They are not evenly distributed thought out your sleep session.  This means that your current pressure is satisfactory, and they are caused by either movement or chin tucking.  The simple act of changing positions will cause a person to hols their breath as they turn.  This can be flagged as an OA event.

Finally, the CAs at the start of your session are probably sleep-wake-junk (SWJ).  This is the transition period between erratic breathing while we are awake and the rhythmic breathing pattern while we are asleep.

I hope I addressed most of your questions.


- Red

[SleepingFish]

Sleeprider :

Thank you so much for the detailed reply. It really is amazing work that you do here out of the goodness of your heart, and I thank you from the bottom of mine. You really are a hero.

>  FL 95% statistic of 0.21 and 99% at .44, but also by the relatively long inspiration time of 2.28 seconds, compared to much shorter expiration time of 1.94 seconds. 

So just for science, what would happen if I kept my current setup (no APAP, no EPR) and I bump my pressure from 8 to 10.  FL 95% and FL 99% should both go down, yah?  What am I looking to get as a target metric for my FL 95% and 99%? 

I assume the extra pressure would cause inspiration time would also go DOWN, but expiration time would go UP?  Is my goal for them to be "even", or what are we trying to achieve from a theraputic level comparing inspiration vs expiration?


As an added piece of data that may not be captured by the graph, I am a 40 year old fairly fit male. Max of 15 pounds overweight, and can run marathons (though not at peak fitness right now). Looking back I think Sleep Apnea crept up on me starting around 30 and got a little bit worse year by year, until I was 39 and a zombie all the time (sleep study AHI was 16 FWIW).


Crimson Nape 
When I first got setup, I had an EPR of 3, and also tried 2. In both cases, I had a buttload of CA events.

[SleepingFish]

Here is my flow rate for a good time, a bit zoomed in. I am not seeing the flat peaks like in the wiki. Is it possible I got into a bad position (say accidentally to back) and that made the flow limit?

But the flow rate by my RE, maybe?

[Crimson Nape]

Please provide a more complete screenshot of your Daily screen.  Make sure your View is set to "Standard" and then use the F12 or Fn+F12(for a Mac) to take the screenshot.  The detailed data on the left really helps is reviewing your parameters and making recommendations.

- Red

[mesenteria]

Raising your pressures, either one, runs the risk of introducing treatment-induced central apnea.  There's a reason why people are prescribed certain pressures, even if we often have to fiddle a bit with the prescription to get it 'just right'.

[Sleeprider]

Increasing pressure will further stent the airway and may reduce flow limitations. With conventional CPAP, obstructive hypopnea and flow limitation is indeed treated with a higher pressure. I'm not sure it will increase expiration time, but the ratio should look a lot better.  You can see this in the decision-tree in the Resmed CPAP Titration Protocol below.  Generally we seek to achieve a normal I:E ratio of 1:1 (inspiration is the same as expiration), to 1:3 (inspiration is 1/3 the time of expiration).  When see inverse ratio, we know that is the result of effort or straining to get the breath.  

What you need to recognize is that with the Resmed Autoset, you actually have a bilevel machine with pressure support limited at 3-cm. I can show you flow charts with mask pressure that prove the pressure delivery between the Autoset and Aircurve bilevel is identical or very similar.  Now with a bilevle titration protocol, notice that once OA events are addressed, it is IPAP, or PS that is increased to treat hypopnea, RERA/flow limitation and snoring.  So if we think about using your Autoset as a bilevel, we can optimize your titration better, by using EPR to our advantage rather than just pressure.  So we maintain the EPAP at 8.0 and add IPAP by increasing the set pressure by the same amount that we add EPR. This maintains EPAP 8.0 and with EPR 1 we have 9/8, EPR 2 is 10/8 and EPR 3 11/8 in bilevel terms.  Are we on the same page with this rationale? If EPR stimulates CA events, then we are back to CPAP with little or no EPR. Hopefully these thoughts and titration approaches are helpful.