Flow limitations and other questions

[sleepless badger]

Hello all:
I have been using APAP since late Dec., 2017.  It hasn't been the easiest of journeys.  However, I am doing better - but am hoping to continue to improve particularly regarding flow limitations that remain a concern for me.

The following are changes I have made to improve my results.

1.   I have turned EPR on to 2. I tried 1, 2 and 3 with 2 feeling most comfortable. This has somewhat tamed my flow limitation graph (tho it is still not pretty), and has changed the trace shape of my individual breaths so that they are a bit more rounded and not quite as sawtooth. Also, I am feeling much more rested most nights.  In addition, this has increase my tidal volume to what I understand is a more normal amount for a women of my size (110#).  Before the change to EPR of 2, I was somewhere in the 260 range.  

2.  I use a double layer of micropore tape along with headband idea over top. This has really improved my leak line and I am no longer getting large leak warnings.  A chin strap doesn't work well for me as it pushes my jaw back a bit further narrowing my airway.  

3.  I requested oximetry testing due to concern with clusters of hypopneas - it took forever to get this scheduled as the DME had persistent problems with the computer software to read it. However, it is finally done and that leads to my questions.

I have a Dr. appointment for this coming Friday to go over the results of the O2 testing. This appointment was originally scheduled for this past Wednesday with the nurse practitioner, but I got a call the day before from the office telling me that they had rescheduled this with the actual sleep Dr.. I am apparently beling "squeezed in". I have never met this man as my only two appointments with this sleep dept. office have been with a PA and the NP - the usual wait for an appointment for the sleep Dr. is 4 - 5 months. So...I am a bit alarmed! I want to have my ducks in order when I go and while I know that I want to address the O2 testing results and flow limitations, I was hoping that others could look at my sleepyhead chart of that night and give suggestions. (I suspect I originally started many years ago with what would now be called UARS and in fact, that was the diagnosis in 2006 following a sleep study which showed low AHI, but significant oxygen desats.  I used a MAD successfully for many years, but now have Obstructive sleep apnea overlaid on the UARS.)

You will see that ugly cluster of hypopneas (the whole reason I request the testing).  I don't always have that many - but I do usually have clusters which I assume are when I am in REM sleep.   - Am I looking at bipap?  

As a side note, this a higher AHI than I have had for a bit - I am usually running in the range of .8 to 1.3 or so.  I was having trouble sleeping with that wrist thing for the testing.  Also up 2 X with my legs - have been taking magnesium with fairly good success - but was having more difficulty that night - usually I am up on 1 X often about 4 - 5 hours into the night.

Here is the Sleepyhead chart from that night along with one from more recently for comparison - no ugly clusters on that night - and a pretty good AHI for me.

[attachment=8426]


[attachment=8427]

I would appreciate any feedback and suggestions.
Thanks:  Sleepless badger

[Walla Walla]

About the best thing you can do is increase your EPR to 3cm. When you see the Doctor I would bring up the idea of switching to the Resmed VAUTO. It will allow you to have greater pressure support to combat the flow limitations. The AirSense 10 is a good machine but with only 3cm EPR it's limited to what it can do for flow limitations.

As far as O2, again increasing the EPR 3cm along with increasing pressure will help a little. But a BPAP type machine like the VAUTO is really what you need.

[Sleeprider]

I agree with Walla on the possibility of bilevel (Resmed Aircurve 10 Vauto). This article in our wiki should help you prepare. http://www.apneaboard.com/wiki/index.php..._and_BiPAP

You really don't have an OA problem, even with a minimum EPAP of 10.40 (I'm going to use bilevel setting terminology in this post because I think that is the better solution). Bilevel will allow lower EPAP pressures and more pressure support to manage hypopnea and flow limitations. Currently your pressure increases are in response to flow limitations. AHI looks pretty good, even in spite of the clusters of hypopnea. It will be interesting to hear what the results of O2 testing is. It could be the doctor is looking at either bilevel or supplemental oxygen. We won't know until you have the appointment. If the finding is that you have a low oxygen level at times, the real question I think you should keep in mind is "should I treat the symptoms of low O2, or the cause of the symptom, flow limitation"?

[sleepless badger]

Wallawalla and Sleeprider:. Thank you for your thoughtful replies!
Further question, I have tried EPR at 3 leaving all other levels the same and have felt pretty awful the next day - little restful sleep and the feeling of waking frequently during the night. On EPR of 3, it feels to me as if the bottom just drops out during exhale and I feel a lag when I go to inhale that is noticeable. Should I be adjusting the upper limit (currently at 16) to 17 when I try this?
Or should I adjust both top and bottom limits?

Sleeprider, I have read the article you kindly included the link for. I am still trying to understand it as it applies to me. I plan to review it before my appointment and hope I have enough time with the Dr. to discuss this.

[Walla Walla]

That's one more reason to ask for a Resmed VAUTO. With the VAUTO you can tailor the inhale/exhale breaths to match your needs. The Air Sense doesn't allow that and neither does the Dreamstation Auto Bipap.

If you increase the EPR to 3 than increase the minimum pressure by one.

[Sleeprider]

A bilevel machine provides "pressure support". This is added pressure during inhale. The definition of pressure support (PS) is IPAP minus EPAP equals PS.

Your CPAP machine has EPR, and it subtracts pressure during exhale from 1 to 3 cm. When your minimum CPAP pressure is 12.4, the IPAP/EPAP is 12.4/10.4 which is a PS of 2 over 10.4 cm H2O. Your Resmed CPAP changes pressure the same way as a bilevel, but since EPAP is subtracted from CPAP pressure, it can result in your EPAP being too low. If you want to maintain your minimum EPAP pressure at 10.4 using EPR at 3, then you would need to change the minimum CPAP pressure to 13.4.

If you had a bilevel, we could set a minimum EPAP pressure of 10 or 11 and add as much pressure support as needed to treat hypopnea and flow limitation. The important difference is, the pressure support can be greater, and it never decreases your expiratory (EPAP) pressure setting, it only increases inspiratory (IPAP) pressure.

[sleepless badger]

Thank you both!    As to possible supplimental O2, from a lifestyle point of view - as well as overall health, I would rather address the reason behind possible O2 desat.   We still travel widely, enjoying hiking adventures etc. and with a daughter overseas; it is enough hassle to tote along a cpap much less additional other supplies.  

Would a machine such as the ResMed Vauto have the same delay upon inhale that I perceive with using the EPR feature on the AirSense 10?  Or would the increase in pressure for inhale be immediate upon end of exhale?   Does the machine "adapt" to the users breath pattern?   The two times I have attempted using EPR at 3, it felt as if I had to fight to get air started.  I did increase the minimum pressure by 1.0 cm the last time I tried the 3 setting.  
I do know that I am extremely sensitive to ANY change in sleep whether with the apap or sleep environment etc..

[Walla Walla]

This is how it's described in the VAUTO manual: "The device has adjustable trigger/cycle sensitivity to optimize the sensing level according to patient
conditions.
Under normal conditions, the device triggers (initiates IPAP) and cycles (terminates IPAP and
changes to EPAP) as it senses the change in patient flow. "

You can lengthen or shorten the time between inhale and exhale. You can also adjust the duration of the inhale and exhale.

[sleepless badger]

Thank you!   I will report back following my Dr. Appt. on Friday.

[sleepless badger]

I am sorry, but I didn't get a reply posted yesterday.   So very disgusted with the sleep Dr.  Results of o2 testing indicated overall o2 for the night at 96%.   One desat to 89%, but not during the cluster of hypopneas.   Was a bit later in the night.  Dr. Totally discounted Sleepyhead information I provided which included a print out of that night, a closeup of the hypopneas and the flow limitation information.   He apparently goes only by ahi and only thinks flow limitation data is valid if done in a lab with an esophageal probe!
I forgot to get a copy of the o2 report -so will try to get one on Monday.
I am considering getting a ResMed Vauto as you have recommended and going my own route (with help from members here!).   I am looking at a gently used one thinking I could always use it as a backup machine in apap mode.   Does this seem like a reasonable course of action?
I am 9 months into use of my current apap and am Medicare.  I have met the compliance requirement during those first 90 days.    Do I still have to demonstrate that I am using the current machine to continue to have Medicare pay their share until the machine is mine?   I googled this, but the information wasn't very clear.
Many thanks for any help!
Sleepless badger