Discussion for Robert W Daly.

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Permalink Reply by Robert W Daly on November 28, 2011 at 15:47

Hi, I'm in the colonies too, in fact in Massachusetts we started the whole ruckus.  First, "complex sleep apnea" in the U.S. is sort of an insurance concept, not exactly a scientific one as currently defined.  What we are really talking about is periodic breathing and in some cases full-out Cheyne-Stokes respiration.  What surprised us was that the events can be partly or even all obstructive, but you know it is happening when the events are highly regular, dominantly occur in NREM sleep and go away during REM, and are spaced around 55 seconds apart +/-15s or so.  For the scientifically inclined, the cause is mostly excessive sensitivity to changes in blood levels of carbon-dioxide.  So, first you have to understand that the AHI is not really a sensitive measure of what is bothering the patients.  They have come in because of the terrible autonomic arousal burden, not because of their O2 status, which usually isn't really so bad anyway.  Hundreds of heart rate spikes is a better indication of the severe autonomic arousal stress that is destroying their lives, but to see them you need to scale the channel correctly--say 50-100bpm.  It breaks my heart to read these posts where people are hoping that their AHI will drop further from the existing level of like 30.  I want to cry when I read these posts because I know for sure how they must feel.  I am of the opinion that there are more effective means of abolishing unstable neurological control of breathing than APAP, BiPAP, etc but this is not for me to decide, it is for people who know a lot more about it than I do.  The key is stabilizing and normalizing blood gases, and lowering CO2 with air pressure just seems like heading in the wrong direction.  So, what do my research friends do?  The reason I posted such a strong statement about self-treatment is that we published some papers and some people read them and started trying it at home.  One very nice lady had gotten it so wrong that she could have asphyxiated herself.  It was very frightening.  This absolutely, positively, cannot be done by the patient.  So I cannot even hint at what has been done for fear that people will self-treat.  But you have my name and you as a professional know how to look up papers that I have co-authored in sleep journals, so I suggest you have a look, and very quickly focus on my co-authors, because I'm just a mechanic.  Talk it over with physicians who refer to your lab.  Incidentally, this is absolutely identical to what normal people look like at high altitude on the first couple of nights, so you must see a lot of this.   

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Permalink Reply by RockRpsgt on November 29, 2011 at 20:15

I have read several of your papers. Brenden is a great tech and role model for those of us that are newer to the industry. I can see how the rebreathers might cause some problems if not made correctly. My question is thus. Titrating dead space is primarily used for central sleep apnea and not complex. Correct?

 

 

The article in the Journal of Clinical Sleep Medicine was amazing! I have a copy of it hanging in my lab.

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Permalink Reply by Robert W Daly on November 29, 2011 at 22:11

The following is 100% the opinion of a patient, and not in any way meant to suggest that anyone but I endorse this view.  I arrive at these conclusions based on brutal personal experience, 15 overnight sleep studies, many done by the incomparable Brendon, and hundreds done with a full PSG system at home. 

Depends on what you mean by complex.  Insurance definition, completely irrelevant to the patient's complaint, is failing CPAP on the titration night by exhibiting specifically central apneas, per the official definition of same.  This definition was created in 2006 as part of a strategy that made it possible to fit complex apnea into an existing code.  I ignore it except to the extent that it gets the DME company paid.  This is not a definition of a disease, it's more like an adverse drug reaction.  BTW, papers that suggest that this problem is resolved after six months on CPAP use the AHI and thermistors to prove this concept.  O2 sat is not these patients' problem, arousals are.  So real-world patients with severe autonomic arousal burdens in my experience tend to disagree.  Use finger pleth, heart rate, PTT or anything but the AHI to see how your therapy is working.  If all else fails, ask the patient how they feel (joke).      

Real definition of complex=dominantly chemoreflex driven events of any kind, identifiable by highly regular repetition at interval about twice as long as it takes a change in breathing to show up at the fingertip.  So, let's say the sat channel is trailing flow by 25s.  Double that.  Now, if events are repeating like clockwork at 50s or so, are dominantly in NREM, REM is better than NREM, this is chemoreflex-driven SDB and it is the parent category for central, CSR, complex, you name it.  These patients are at almost 100% risk of failing CPAP, I personally wouldn't even try it except for reimbursement reasons.  Typically, their PaCO2 is like 37-38 mm Hg or lower.  Put them on BiPAP and you're looking at <35 in a lot of cases.  Events can be obstructive, mixed, central, central hypopneas--what matters is the arousal, which you will notice always occurs around the third recovery breath.  Why is that, by the way?  Your mission is to abolish the arousals, so you need to be looking at them and unless you have very fancy stuff the heart rate is at least one possible way as long as you don't scale it from 0-150.  Success is perfection in NREM, as in O2Sat is +0%/-1% for fifteen minutes straight.  See if you can do that with an APAP. 

This second definition of complex describes an actual disease, meeting all of the requirements of same.  The point is, CPAP may just not be indicated in this disease.  There are two crucial rules:  1)Blood gas must be normal and must remain normal and must not budge from normal.  2)  There really should be more or less zero autonomic or cortical arousals except at stage transitions.    If you can do this, the patient will name you in their will.

Do you have access to an IRB?

 

 

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Permalink Reply by RockRpsgt on December 1, 2011 at 7:25

IRB? Independent Review Board? Sorry that one is above my head.

 

Unfortunately most sleep labs won't allow blood gas test anymore.

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Permalink Reply by RockRpsgt on December 1, 2011 at 8:59

Or more than a 3 lead ECG. ;(

 

Sleep medicine seems to be in the 2 step backwards process. Hopefully after all this budget cutting BS is done we can take 3 steps forward again.

RockRpsgt said:

IRB? Independent Review Board? Sorry that one is above my head.

 

Unfortunately most sleep labs won't allow blood gas test anymore.

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Permalink Reply by Robert W Daly on December 1, 2011 at 15:52

I know what you mean.  The thought, though, is that if one of your referring doctors could go to their hospital IRB to get approval for a pilot program, you could definitely set up to help a lot of people.  As far as equipment, it would probably be necessary to borrow an end-tidal CO2 monitor if you don't have one, but other than that your lab probably has everything already.  The fix, as you already know, costs almost nothing.  The part that is so crucial is that the official definition of "complex sleep apnea" is not ideal for patient selection, instead careful recognition of NREM-dominant, chemoreflex-driven disease is the key.  And, the most telling thing in recognizing these patients is not the event type, but the highly characteristic timing of events. 

When I say blood gas should be normal and stay normal, I'm really talking about what you'll see on the end-tidal monitor.  Many current therapies take a patient with mild respiratory alkalosis and make it much more severe.  The patient won't feel right until CO2 is moved closer to normal, and the therapy you use should not make it abnormal.  The bit about arousals is that we are trained to look at and score cortical arousals, and since we can't directly measure blood pressure spikes we tend to under-emphasize the autonomic arousals.  But there is plenty of information about that if you look at it correctly, and a place to start is the pulse channel. 

 

Anyway, it's an opportunity to help a lot of people, which is a great blessing.  If there is anything at all the Boston folks could do to help you and your referring physicians you would all receive a very warm welcome and a lot of support. 

 

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Permalink Reply by RockRpsgt on December 2, 2011 at 0:20

I will bring it up in the next meeting. Moving from the huge medical complex of the IU med school to rural colorado has been like taking a step back in time. I was a contract traveler when  I first arrived. My first lab had a Co2 monitor and did not know how to use it. It took my entire contract to get everyone up to speed. Educating those higher than me on the importance of Co2 monitoring  other than peds has been a lesson in patience to say the least. I started with an emphasis on those with a BMI over 40%. Next the conversation went to complaints of dyspnea and syncopy. Not long after winning the battle my contract ended.

 

You would not believe the fight I have had getting techs and docs to buy into the central hypop theory. I have been told they don't exist and no matter what you always raise the pressure for hypopneas. This was a sleep educator! You would think at this altitude they would have a better understanding of centrals as it's a nightly sight.

 

Anyways thank you very much for your continued support.

 

RockRpsgt

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Permalink Reply by Kath Hope on December 2, 2011 at 0:29

This is all very educational Rock and Robert - thanks for sharing your discussion publicly :)

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Permalink Reply by Robert W Daly on December 2, 2011 at 2:46

This is why I love sleep technicians, because they are face to face with the patient, and the observant ones know truths that the physicians just don't have to face.  In the U.S. I'm very sorry to say that all too many physicians prescribe from the scoring report and don't even look at a single page of the sleep lab tracings.  But the sleep technicians see the facts about treatment failure up close and personal.  It therefore comes down the fact that the sleep technicians must more forcefully communicate the truth that CPAP not only fails extremely frequently and cannot be made to work by itself with a very meaningful percentage of patients, but in fact that it actually makes enough patients worse to the point that if you are working in a four-bed laboratory, you see such a patient as often as weekly.  I am one of them, so I know this at a personal level.  And, as RockRpsqt very accurately reports, with many, even board-certified sleep specialists, this simple fact of life is something that can meet with well intentioned skepticism or even outright resistance. 

But, how do you overcome bad science?  With good science.  And that is what I am determined to devote the remainder of my life to, promoting science that will make it absolutely clear to every sleep physician that better therapies are both needed and possible.  There are so many lives to be saved.  Patients can help in this process by directing their frustrations not inward, but back to the sleep medicine community, stating in no uncertain term that being given a therapy that leaves you with a score of 30 is being given a therapy that has failed miserably, and that it should not be our obligation to address this failure.  The absolute responsibility to recognize and admit to the majestic scope of the public health problem that remains to be solved lies with sleep medicine, not with the sufferers.  Since sleep physicians are on the whole dedicated, caring and highly intelligent people I am confident that more good science and better therapeutic alternatives will ultimately win the day.

In the meantime, to RockRpsgt, if we can help you with papers and evidence, please contact me directly (Kath can arrange that, I think) and we can load you up with whatever you need.  If we can help one patient that comes through your lab, it's worth it. 

  

 

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Permalink Reply by RockRpsgt on December 2, 2011 at 11:38

For the record I prefer technologist over technician.;)

 

I have been thinking about doing something different here in Colorado for some time Robert. Even to the point that I have excepted that it may result in my finding new employment. Let me do some research and think on it. I will be back soon. Ty for the convo and the support!

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