Need guidance for complex sleep apnea and leaks follow-up

[jmayer180]

I've had the usual struggles over the last 13 years gradually getting recognition that I have severe complex sleep apnea.  After a great amount of help from Sleeprider, Roby Sue, and many other mentors, I've finally been on a ResMed AirCurve S10 ASV for the last three years and saw disappearance of CA's and very low UA's, but with persistence of hypopneas, with AHI’s usually in the single digits.  I've felt fairly well, still some nap attacks but I am obese (there, I said it) and old (77) and arthritic.  My sleep doc thought that was about the best I could hope for.  I've been complacent the last few years and the doc has spaced my follow-ups to annual visits with prn email contact in interim.  Now he has retired and I am about to face a brand-new sleep doc (with a Pediatric background) and have no idea what her philosophy will be.  


I seem to have forgotten what little I learned from the Forum and couldn’t explain the difference between a flow limitation chart and a decibel.  (I hope that is not a prodrome to a different medical issue coming - knock wood!)  But it does seem that my total AHI's are starting to creep upwards, mostly from hypopneas.  I hope for some adult reassurance or suggestions for preparing for my New Doc visit.  I'll enclose a two-year Oscar Statistics chart, and a two-part Oscar graph with the six recommended charts for 11 Nov 2021.  That is a fairly typical day for the last couple of years.  Since then, I’ve played around futzing with a few pressure changes, and also switching temporarily to a different nasal mask to rest my battered forehead.  Times past I would experiment with setting changes, but finally became convinced that with the ASV the machine pretty well regulated itself.  

I have tried nearly every mask known to man and get the best results with the Mirage LT, but periodically I need to get it the pressure off the forehead and use one of the nasals that has the non-forehead strapping system (like the Airfit N20).  I have more trouble with leakage then, and this has been a long-term problem which I blame on my usually high pressures and perhaps a pudgy face.  and that raises one of my main questions…. how much does my usual relatively large leak rate affect my numbers?  And does anyone have suggestions, assuming the hypopneas are fairly reliable, in how to reduce them?  


  Oscar Stats Mar 2019-Nov11, 2021.pdf (Size: 420.49 KB / Downloads: 6)

   

   

[SarcasticDave94]

I see two possible problems with your therapy. One is high leaks, likely mask leaks due to the spikey pattern on the chart. Second, possibly these Hypopnea might be Positional Apnea clusters.

Leaks at this rate will affect therapy effectiveness and accuracy of reporting.

[Sleeprider]

Your tidal volume and minute vent are abnormally high with median values of 9.13 mL and 10.63 L/min respectively. Without a pulmonary workup, it's hard to know if much of this is dead-space air moving, or excessive inflation caused by the high minimum PS. We can't ignore the potential error your high leak rate may be introducing to the detection of respiratory flow. In any event, the Resmed ASV wants to target this high vent rate, and is pushing the maximum PS a great deal of the time. When this pressure support fails to hyperinflate your lungs, based on the respiratory airflow measured, it marks a hypopnea. It is my theory that you are unable to exhale enough air from time to time to create room for this extraordinary air volume, and that the automatic pacing of the Resmed ASV may aggravate this problem for you. It would take close examination of the respiratory flow, mask pressure, tidal volume and minute vent to evaluate any asynchrony between your needs and the ventilator. This reference briefly discusses some of that, but there are many other possibilities including breath stacking this does not cover https://www.ers-education.org/lrmedia/20...298531.pdf

We don't know from the mile-high view why you have hypopnea, and even with closer examination of the flow rate, we may or may not figure it out. It might help to think back at past pressure and pressure support settings to consider what worked best, or if the hypopnea have always been present. I suspect a lower PS min would help you to more completely exhale. You might also be someone that could respond better to the manually set pace and volume of the Philips SV machine.

[Geer1]

A lot of ugliness in this graph and it makes it a bit tough to know where to start. My first thought was why are you using PSmin of 6 cm with an ASV? Do you have a logical explanation for this?

The advantage of ASV is that it manipulates PS and the Resmed you now use does so aggressively. I find it unlikely you need this high of PSmin and if you do I think there may be other issues.

Too high of PSmin could be causing these hypopneas and it also limits the min EPAP which limits your ability to treat central apnea. Right now your settings are kind of handcuffing the machine making it ineffective at treating both obstructive and central issues and it really isn't clear what is the primary issue.

My recommendation is to step back and run through some different settings on a learning curve to better try and understand what is going on. If you are willing to give this a try my first change is to reduce PSmin to 3 cm with no other changes. If the results seem somewhat promising stick with this for a while, if there is something obviously wrong then post it up so we can see why.

I see you have an oximeter and would like you to use it when trying these different settings so we can see of oxygen levels are affected by these changes.

[jmayer180]

"Sleeprider: It would take close examination of the respiratory flow, mask pressure, tidal volume and minute vent to evaluate any asynchrony between your needs and the ventilator. "

FWIW.  I'm struggling through your reference.  I'll leave PS at 3 and try to be patient for a few days.  In past, I never saw much dramatic movement with PS changes.

      

[Sleeprider]

We need to find a way to clean up the leaks. The leaks are certainly the most important factor affecting your sleep quality and integrity. As far as trying to determine a cause for hypopnea events. we need to look at the 2-3 minute zooms so we can see the nature of the hypopnea. I wanted to include the tidal volume and minute vent graphs to understand the actual impact of the hypopnea and flow rates. Your respiratory volume is so high that the hypopnea are essentially non-events with tidal volume near 500 mL and minute vent over 6 L/min which is normal for most individuals.

[jmayer180]

Do these  help at all?  Can't seem to find how to zoom properly. 

   

   

[Geer1]

Use mouse to select a portion to zoom to (click and drag) or use arrow keys then can do a regular screenshot in Oscar.

You say you don't notice a correlation with PS but in the summary data you posted some of best results were at PS of 4. The problem with PS is that you said you have complex apnea. Min PS and central apneas are not friends and it is often counter productive. PS is also not how you treat obstructions. PS is a last stage resort for restrictive breathing that cannot be resolved using other methods. I believe you have many options to test before settling with a high PSmin. My recommendation to try PSmin of 3 is to see it as a baseline in comparison to these current settings before we start trying other changes.

[jmayer180]

Which graphs should I zoom? Willco with the PS 3.

I'm still clueless enough not to know how to interpret Leaks. What l/min over med/95%/95.5% is acceptable? .All the mask guides say "Do not overtighten" but I have to have pretty durn tight straps and often a supplemental band over the face to get anything like a leak reduction.

[Crimson Nape]

The zoom function is global to all graphs in the Daily screen. Use the F12 key to capture the screenshot image. The screenshot will provide much more information than using the "Print" option for our purposes.