Clear Airway Apneas

[philthyphil]

Hi there,

I've just started using the OSCAR sw and completed my 1st import. I seem to have quite a high rate of Clear Airway apneas and was wondering whether this is quite normal for CPAP users, or whether I should look into this more.

My Clear Airway score is almost always higher than my Obstructive or Unclassified scores and last night was 5.22 compared to an Obstructive score of 1.86.

When I first put my mask on I usually concentrate on my breathing for the first minute or so to make sure the fit is good and the machine is working OK, but when I let my mind wander off I quite often just stop breathing and gasp for air, and have to pant to get my breath back. This can happen quite a few times before I nod off, but it looks like it's happening while I'm asleep as well.

Any advice would be great.
Phil

[Sleeprider]

It seems you are new to OSCAR but not to PAP therapy. We don't know anything from your description about your machine, settings or timing of the events. AHI at this level can be the result of a variety of things, and may be something we can help. Please post a copy of the daily details chart and we can quickly interpret the results for you. Instructions for Organizing your OSCAR chart and attaching to a forum post are in my signature links.

[philthyphil]

Hey Sleeprider

I tried, believe me I tried...

After about an hour of following your instructions to prepare and post images, I was greeted with this...

Please correct the following errors before continuing:

• I'm sorry, brand new members are not allowed to post images until they have 4 posts.
  

I will write a couple of other posts about some other issues (without images of course).

Disgruntled Phil

P.S. what do others do in this situation - put up 3 random meaningless posts? Doesn't seem to be a policy designed to encourage rich content.

---

Weird - are my images there anyway? My head is about to explode.

[optimalsleep]

My machine has a test option and shows on the screen whether or not if you are sealed.

Your machine is fixed and ramp up would be nice to possibly compensate possible leaks. I didn't see your leak rate cart. As Sleep rider mentioned, organize your charts and we'll be able to see what's going on with you better.

[jaswilliams]

Yeah Pictures...


OK I would try reducing the EPR to two as you have a bit of periodic breathing adding to your CA score it will likely reduce over time as your a new user

[philthyphil]

Hey Optimalsleep,

It's not a leak problem - I have very few leaks if any (and they are on the charts).

It's just me stopping breathing for some unknown reason.

---

Yeah Pictures...


OK I would try reducing the EPR to two as you have a bit of periodic breathing adding to your CA score it will likely reduce over time as your a new user

Hey, yep I'm not actually new to CPAP (about 15-20 years) just new to OSCAR and this forum. I will look into the EPR options (don't really know that much about it). Thanks.

[Sleeprider]

At least in this image, we see CA events are highly clustered and that after the first pause in breathing that is not even flagged, you get into a kind of feedback loop of CA followed by recovery breathing (larger flow and volume than normal), and the cycle repeats, and slowly decreases becoming variable or periodic breathing before normal respiration is seen at the end.  It's a very interesting sequence, that we have seen before. We think what happens is that following the first pause, you take a large recovery breath which may lower  your serum CO2 (HCO3) casing minor hypocapnea which reduces respiratory drive. We can see flow diminishes then suddenly increases as HCO3 increases and spikes your respiratory drive resulting in more recovery breathing that terminates in a full CA event.  This is a feedback loop that begins with a minor non-event but then amplifies through the sequence. At the end of the cluster your respiration rate increases to more breaths per minute of smaller flow and goes through several oscillations before normalizing. 

This pattern can be exacerbated by pressure support or EPR which tends to increase ventilation to where the apneic threshold is reached.  Reducing EPR or pressure support may help to make this feedback loop less likely to occur or eliminate it altogether.  You are using fixed pressure of 13.4 with EPR at 3 which is a bilevel pressure of 13.4/10.4.  There is nothing wrong with your respiration or neurology, this is just a high sensitivity to increases or decreases of CO2 which directly impacts your respiratory drive (apneic threshold).  I think if you reduce EPR you can also lower the pressure by the same amount (12.4 with EPR 2).  These events may appear disturbing to see until you understand them and realize they are not particularly harmful to your health or sleep.  You may choose to ignore this unless it is a common occurrence or happens fairly often or for longer periods of time.

[philthyphil]

At least in this image, we see CA events are highly clustered and that after the first pause in breathing that is not even flagged, you get into a kind of feedback loop of CA followed by recovery breathing (larger flow and volume than normal), and the cycle repeats, and slowly decreases becoming variable or periodic breathing before normal respiration is seen at the end.  It's a very interesting sequence, that we have seen before. We think what happens is that following the first pause, you take a large recovery breath which may lower  your serum CO2 (HCO3) casing minor hypocapnea which reduces respiratory drive. We can see flow diminishes then suddenly increases as HCO3 increases and spikes your respiratory drive resulting in more recovery breathing that terminates in a full CA event.  This is a feedback loop that begins with a minor non-event but then amplifies through the sequence. At the end of the cluster your respiration rate increases to more breaths per minute of smaller flow and goes through several oscillations before normalizing. 

This pattern can be exacerbated by pressure support or EPR which tends to increase ventilation to where the apneic threshold is reached.  Reducing EPR or pressure support may help to make this feedback loop less likely to occur or eliminate it altogether.  You are using fixed pressure of 13.4 with EPR at 3 which is a bilevel pressure of 13.4/10/4.  There is nothing wrong with your respiration or neurology, this is just a high sensitivity to increases or decreases of CO2 which directly impacts your respiratory drive (apneic threshold).  I think if you reduce EPR you can also lower the pressure by the same amount (12.4 with EPR 2).  These events may appear disturbing to see until you understand them and realize they are not particularly harmful to your health or sleep.  You may choose to ignore this unless it is a common occurrence or happens fairly often or for longer periods of time.

Wow what a great answer - thank you. I understand what the theory is and I've just changed my pressure and EPR to 12.4 and 2 - see how I go over the next few nights.