questions about flow rate waveform

[tedvpap]

questions about flow rate waveform.  I think the attachments show examples of what I'm asking about.

1.  is the pattern I think I'm seeing really a pattern? it looks like centrals are generally just at or slightly above the 0 flow line while obstructives are generally below the 0 flow line. not sure why this would be so, though, if not-breathing is by definition equal to the 0 flow line; unless apnea isn't necessarily a full 100% cessation of breathing...?

2.  I see quite a few flows that look like apnea but are shorter than 10 seconds.  is it fair to say that shorter 'events' - and the more of them you have - are as bad or almost as bad as an apnea meeting the clinical definition? it looks like sleepyhead has an option to track user defined events. is a proactive doctor likely to take shorter events into account if I bring them to his/her attention or are their actions limited to the 10+ second rule? 

3.  I see quite a bit of uneven breathing, especially before and after an event.  should we expect that if therapy resolves the apparently-associated events, the apparently-associated ragged breathing would resolve as well?  or is uneven breathing something different? and is that treatable?

thanks.

1.  No pattern.  Zero flow rate means that the actual flow rate is equal to the vent rate.  Whether it is due to obstruction of central can not be discerned.  

2.  No way of saying how many near apnea events equals a real apnea event since definitions are arbitrary and everyone is different.   I know of no doctors that look at data on a breath by breath basis.  They tend to work based on summary statistics.  

3.  There is always problematic breathing surrounding apnea events.  If your OSA was better treated, you would have fewer OSA events, and fewer OSA related "non-events".

I understand you did not ask but I think it is important to state:  when diagnosed with OSA, properly treat the OSA before chasing after other theories.   

I hope this helps.

[sheepless]

tedvpap, many many thanks for the clear and direct answers.

I'm a little nervous about posting this but I want to respond to your last comment / admonition:

first, thanks for the reality check (really). it's sound advice. I understand and appreciate the value of being systematic and honing in on a known problem rather than going off half-cocked hypothesizing (inventing?) other problems. however, in my mind, circumstances warranted it.

let me explain. what follows can be gleaned from other threads but to consolidate:

I was initially diagnosed with csa, not osa. more recently I was diagnosed with osa but I suspect that was for the convenience of the doctor and insurance company as I had nearly equal csa:osa on the night of the sleep study. commenters in my threads have noted csa's but are mostly uncertain as to whether I'm a candidate for a different modality, I think partly because I guessed which charts to post and the charts I chose to post in various threads for various purposes vary themselves, and ultimately that is because the efficacy of my therapy has been variable. even Sleeprider figuratively threw up his arms as he indicated my situation (fragmentation in particular) is not within his experience. honestly, I felt left to "chase after other theories" because it seemed I had run into a dead end on this forum and because osa alone doesn't seem to satisfactorily explain my issues (higher than desirable ahi's, variable ahi's on any particular setting, terribly fragmented sleep, and continuing to be all but completely useless after 18 months of apap). as for chasing down osa problems first, as you suggest, I have made direct requests for help resolving awakenings associated with flagged (mostly osa) events (thanks WallaWalla for pointing out positional clusters). I have made direct requests for help figuring out the cause of so many unflagged awakenings and sought opinions with regard to whether (obstructive) disordered breathing might be causing them (thank you tedvpap for pointing me to UARS). rather than give up, I've tossed speculative ideas out there trying first, to canoodle out on my own what ails me, and second, to trigger informative responsive posts like yours, detailed and specific, that I and others can learn from. in my ignorance I haven't always known what questions to ask or how to ask them without context and explication that I didn't / don't understand. in lieu of that, speculation at least implicitly frame some of my issues and questions. I'm not promoting them, stating them as fact or using them to advise others. notice that a lot of it is in the form of questions or associated with expressions of uncertainty - invitations to confirm or deny and thereby educate. in addition, having reached an apparent dead end, speculation gave me a means to resume interaction with the forum. confirming or corrective responses, no matter to me, are equally instructive. my feelings aren't hurt by being corrected & instructed; I'm asking you to do just that. and while it's up to you and others to say, I don't think responding to my theorizing is a waste of your time precisely because the result is instructive.

in sum, at the risk of protesting too much, these are the reasons I don't think I was blindly or irresponsibly chasing after other theories.

notwithstanding all above, I apologize if by theorizing or by this explanation (defense?), I've overstepped and/or annoyed anyone.

thanks for "hearing" me out. thanks again for all your and others' time and insight and to all that make this apnea community such a great resource. I, for one, am very grateful.

[tedvpap]

tedvpap, many many thanks for the clear and direct answers.  

I'm a little nervous about posting this but I want to respond to your last comment / admonition:

first, thanks for the reality check (really). it's sound advice. I understand and appreciate the value of being systematic and honing in on a known problem rather than going off half-cocked hypothesizing (inventing?) other problems. however, in my mind, circumstances warranted it.

let me explain. what follows can be gleaned from other threads but to consolidate:

I was initially diagnosed with csa, not osa. more recently I was diagnosed with osa but I suspect that was for the convenience of the doctor and insurance company as I had nearly equal csa:osa on the night of the sleep study. commenters in my threads have noted csa's but are mostly uncertain as to whether I'm a candidate for a different modality, I think partly because I guessed which charts to post and the charts I chose to post in various threads for various purposes vary themselves, and ultimately that is because the efficacy of my therapy has been variable. even Sleeprider figuratively threw up his arms as he indicated my situation (fragmentation in particular) is not within his experience. honestly, I felt left to "chase after other theories" because it seemed I had run into a dead end on this forum and because osa alone doesn't seem to satisfactorily explain my issues (higher than desirable ahi's, variable ahi's on any particular setting, terribly fragmented sleep, and continuing to be all but completely useless after 18 months of apap). as for chasing down osa problems first, as you suggest, I have made direct requests for help resolving awakenings associated with flagged (mostly osa) events (thanks WallaWalla for pointing out positional clusters).  I have made direct requests for help figuring out the cause of so many unflagged awakenings and sought opinions with regard to whether (obstructive) disordered breathing might be causing them (thank you tedvpap for pointing me to UARS). rather than give up, I've tossed speculative ideas out there trying first, to canoodle out on my own what ails me, and second, to trigger informative responsive posts like yours, detailed and specific, that I and others can learn from. in my ignorance I haven't always known what questions to ask or how to ask them without context and explication that I didn't / don't understand. in lieu of that, speculation at least implicitly frame some of my issues and questions. I'm not promoting them, stating them as fact or using them to advise others. notice that a lot of it is in the form of questions or associated with expressions of uncertainty - invitations to confirm or deny and thereby educate. in addition, having reached an apparent dead end, speculation gave me a means to resume interaction with the forum.  confirming or corrective responses, no matter to me, are equally instructive. my feelings aren't hurt by being corrected & instructed; I'm asking you to do just that. and while it's up to you and others to say, I don't think responding to my theorizing is a waste of your time precisely because the result is instructive.    

in sum, at the risk of protesting too much, these are the reasons I don't think I was blindly or irresponsibly chasing after other theories.  

notwithstanding all above, I apologize if by theorizing or by this explanation (defense?), I've overstepped and/or annoyed anyone.

thanks for "hearing" me out. thanks again for all your and others' time and insight and to all that make this apnea community such a great resource. I, for one, am very grateful.

Thanks for explaining - I didn't realize that there was a back story.  I am terrible with recognizing names so I didn't realize we have had other interactions on other threads.  
I sent you a PM.

[Sleeprider]

Sheepless, we have discussed ASV in the past, and have tried to make CPAP work reasonably consistently. Your breathing pattern and AHI reminds me a lot of another member, Spy Car. He ultimately ended up on ASV, but I think it would be interesting for you to go back to his threads from a year ago or more and see how his journey proceeded. I'm pretty sure you will see similarities, and if ASV is appropriate for you, his story can give you a lot of insight on productive ways to proceed.

ASV has a number of interesting tricks that would work to benefit you. It can eliminate CA and hypopnea through pressure support, but it also evens out the respiratory volume and rate (timing). The erratic breathing patterns you show in some of your graphs are examples where ASV will prevent the lost breath, or even out the volume of the ones that are so uneven. The minute vent and respiratory rate are targeted in the Resmed machine based on your own baseline resp rate and volume, so it eventually feels natural and comfortable. ASV takes some getting used to. I think your sleep studies offer important clues that your therapy on CPAP is not appropriate, and your results show you are only marginally treated and still have excessive AHI. Take a look at Spy Car's old threads and maybe it's time to move forward to change your therapy.

[sheepless]

thanks Sleeprider.  elsewhere you mentioned spycar and another I can't remember off hand and I have read through them both.  I see similarities with me in those and elsewhere where apap works okay but not well enough.  I guess the problem is that while my apap ahi's range from around 2 - 20, they average close to 5 - 6 or so, so I'll need to be armed with the charts and statistics supporting my apparent need for a different modality.  a little feedback along this line would help me a lot.  what are the factors or symptoms I exhibit that I should emphasize as an advocate for making this change.  I can't imagine the system denying the chance to try a different modality 'though I guess it happens; I just have to make it happen.  it seems I can find a used machine online or go through the sleep doc system which I should probably do but maybe my biggest problem to overcome at the moment is that I am not currently associated with one (new hmo insurance and they do not have a board certified sleep specialist available unless maybe I go shake the bushes and hope they let me go elsewhere).  I assume if I can find a way to go back through the sleep medicine system, they'll figure out what machine I need.  even so, I would like to be informed enough to know if I'll agree with their assessment.  I'd also like to know, and this is my 2nd question to you now (first one = feedback re symptoms, charts and statistics), what machine (s) you think might work for me that I can look for used.  I think you might have listed a few in a different thread of mine; I'll have to go back and look.  once I know what to look for / ask for, I can use it to advocate for a different therapy through the system and/or find a used machine on my own.  gonna get there, wherever that is, eventually.  especially with all the help and support from this forum.  I appreciate you and others not giving up on me.

edit: actually, on re-read, you might have answered part of my question with your description of asv capabilities.

[allanri]

gwc2795, what would you say the attached waveform represents?

It doesn't seem to match any of the profiles in your post, above.
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