Newbie wondering why AHI fluctuates so much

[Bxbomber]

Hello Ockrocket! Thanks for the suggestions to help keep me on my side! I think I'm staying on my sides for the majority of the night. I'm usually in bed early so I'll have to ask the wife the position I'm in when she comes to bed.

[Bxbomber]

BXbomber, I would guess that it is your minimum pressure rating that is the problem, especially with EPR at 3.  Here is what happens.  The minimum pressure of the machine is 4.0 cm, so you start out at 4/4 pressure (IPAP/EPAP).  As pressure increases it becomes 5/4, 6/4, 7/4, 8/5, 9/6.  I'm not going to get into why that is messed upt, but take my word for it.  

Set your minimum pressure to the median or average pressure you have for the last 7 or 30 days...doesn't matter.  If it is less than 8.0 cm, set EPR so that the minimum pressure will be 4.0.   In other words, for a minimum pressure of 6, set EPR at 2.  When you get a chance, post some data and I'm sure we can come up with something even more brilliant.

Hello Sleeprider! First let me say that as I've been reading and trying to educate myself about sleep apnea I've found you to be one of the most knowledgeable persons on the subject and truly appreciate all the assistance you provide for us all! I will do as you say and adjust my settings. I will post my sleepyhead data within the next day or two.

Hello Sleeprider! I'm stumped but I love the challenge of tweaking things to make them run better. Used to enjoy playing with the timing and adjusting the carburetor on my 69 Chevy so I'm going to approach this the same way.

 I took your advice and changed my min. pressure to 6.2 and my EPR to 2. The 6.2 was based on my avg. pressure for the past week. During the night I thought I wasn't getting a good night sleep since I woke up a few times. Thought for sure that I would feel a bit tired today but when I awoke I felt pretty good and still do! Couldn't wait to see what myAir score was going to be... and there it was 9.8 events per hour! It doesn't make sense? 

Anyway I have my first follow up appt. with my pulmonologist since starting therapy later today. I will post my sleepyhead charts afterwards. I guess chill was right when he said not to get hung up on AHI numbers but go by how your body feels.

[Bxbomber]

Hi Everyone here are my sleepyhead charts from last night. Not sure why the machine settings don't reflect the changes I made yesterday afternoon as per Sleeprider's advice. Anyway I look forward to hearing your suggestions. Thanks again for making dealing with apnea much less daunting! I hope I did this correctly? If not, moderators feel free to delete edit or whatever is appropriate.


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[Sleeprider]

Before this change in AHI took place, did you have mostly central apnea? Did you have a titration study, or were you issued a CPAP for self titration? Do you have a summary of your diagnostic sleep study, in particular were central apnea noted? If you have a screenshot of the Statistics chart on Sleepyhead, that might be useful to see the variation of your results.

Turn off EPR and increase minimum pressure to 5.0. What we want to do is to stabilize your pressure to be as constant as possible. If this is a typical result for you, this suggests complex apnea, and you may be on your way to ASV. Let's kill the EPR first and see where that takes us.

[Bxbomber]

Before this change in AHI took place, did you have mostly central apnea?  Did you have a titration study, or were you issued a CPAP for self titration?  Do you have a summary of your diagnostic sleep study, in particular were central apnea noted?  If you have a screenshot of the Statistics chart on Sleepyhead, that might be useful to see the variation of your results.

Turn off EPR and increase minimum pressure to 5.0.  What we want to do is to stabilize your pressure to be as constant as possible.  If this is a typical result for you, this suggests complex apnea, and you may be on your way to ASV. Let's kill the EPR first and see where that takes us.

Hello Sleeprider up until the past three days when my AHI started trending up last night being the highest I thought I was doing pretty well. Lowest AHI being 0.9 and mostly under 5. Never had a titration study. Here is my statistics chart. I made the changes to my machine as you suggested. Thanks for your insight!

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[Sleeprider]

Thanks for the statistics. You ave never had any notable obstructive apnea, and most events recorded up to now have been CA. Your average pressure is just over 5 cm which is quite low, but that apparently controls the OA component of your sleep apnea. Unfortunately the pressure has resulted in triggering what we call complex apnea. It has been at a low enough level so far that it would not be medically necessary to change the therapy approach from CPAP to something like ASV. So any doctor would look at your treatment and tell you it is effective and you are doing well.

What we need to do is recognize that with CPAP, your sleep disturbance goes from an obstructive apnea, to one that consists mainly of central events. This is manageable, with low pressure and avoidance of pressure support, or a separate inhale and exhale pressure that seems to make that worse. Complex apnea may occur in 10-15% of people put on CPAP, so it's not unheard of, but relatively rare. When you have the follow up with your doctor, you need to make a point of telling him that you have to maintain low pressure to avoid CA events. Hopefully you will be feeling rested and will be well treated, but I would guess it in your best interest to your maximum pressure. The statistics don't look reliable for your 90% pressure, but I'm sure as time goes on, we can identify an appropriate maximum pressure.

Other than the fact you have mild complex apnea with CPAP pressure, your results look very good, and I think it is realistic to maintain your AHI including CA under 2.0. If it starts to go much higher with CA events as time goes on, then there will be nothing CPAP can do to treat that. I guess we can deal with that if and when it happens.

[Bxbomber]

Thanks for the statistics.  You ave never had any notable obstructive apnea, and most events recorded up to now have been CA.  Your average pressure is just over 5 cm which is quite low, but that apparently controls the OA component of your sleep apnea.  Unfortunately the pressure has resulted in triggering what we call complex apnea.  It has been at a low enough level so far that it would not be medically necessary to change the therapy approach from CPAP to something like ASV.  So any doctor would look at your treatment and tell you it is effective and you are doing well.  

What we need to do is recognize that with CPAP, your sleep disturbance goes from an obstructive apnea, to one that consists mainly of central events.  This is manageable, with low pressure and avoidance of pressure support, or a separate inhale and exhale pressure that seems to make that worse.  Complex apnea may occur in 10-15% of people put on CPAP, so it's not unheard of, but relatively rare.   When you have the follow up with your doctor, you need to make a point of telling him that you have to maintain low pressure to avoid CA events.  Hopefully you will be feeling rested and will be well treated, but I would guess it in your best interest to your maximum pressure.  The statistics don't look reliable for your 90% pressure, but I'm sure as time goes on, we can identify an appropriate maximum pressure.

Other than the fact you have mild complex apnea with CPAP pressure, your results look very good, and I think it is realistic to maintain your AHI including CA under 2.0.  If it starts to go much higher with CA events as time goes on, then there will be nothing CPAP can do to treat that.  I guess we can deal with that if and when it happens.

Thanks for all your help and insight Sleeprider it's very much appreciated! I did as you said and set the min. pressure on my machine to 5 and turned off the EPR. I'll see how this goes for a few days and will post the results.