Sierra

Window got too narrow to read or type in!

First just to clarify my diagnosis and treatment, I was diagnosed with an AHI of 37.3. Of that 0.4 was central apnea, and 17.4 was obstructive apnea, with the remainder hypopnea. Clearly untreated I had dominant obstructive sleep apnea. However when I first started treatment with an APAP in auto mode this drastically changed. Unlike my wife who was diagnosed up around 80 for AHI and went immediately to <1.0 for AHI, my outcome was very poor. I can't go back to all the details because SleepyHead "ate" my early data, and all I have left are some random screenshots. I recall AHI's as high as 13 or so. My ratio of CA to OA events went to about 3 to 1. This is a classic case of treatment emergent complex apnea. This is not uncommon at all. I have seen estimates that 6.5% of people treated for obstructive sleep apnea get this treatment emergent complex apnea with high central apnea. That is a large number of people when you consider how many get diagnosed with sleep apnea. Fortunately in most this emergent condition goes away in 6-8 weeks. I was not one of the ones where it went away. I seriously considered at that time going back to my doctor to request a prescription for a VAuto BiPAP or full ASV. But with help from forums and my own research I persevered with changes to my ResMed APAP. If my SleepyHead stats are correct, I have used over 40 different setups searching for an answer. Now with the machine in fixed CPAP mode and a relatively low pressure of 11 cm, and 2 cm of EPR I am finally getting good results with average AHI <1. Still not quite as good as the results my wife is getting (still in Auto mode), but pretty close. My conclusion is that a simple CPAP, set up properly, can be very effective in addressing treatment emergent complex sleep apnea.

I notice that you keep saying an APAP cannot distinguish between central apnea events and obstructive events because it cannot supply missing breaths. That is kind of mixing apples and oranges. Distinguishing between central and obstructive events is done very well with a ResMed APAP. Providing assistance for missing breaths is not a feature of an APAP, and is a totally different issue. The AirCurve VAuto can do that on a very crude basis, and of course as you know the AirCurve ASV does it in a much more sophisticated way on a breath by breath basis. And there are certainly types of complex or pure central apnea that do require an ASV. So far I have not found it necessary in my treatment emergent type of apnea though. If someone requires a significantly higher pressure to control the obstructive portion of the apnea, this fixed pressure option may not be effective. A BiPAP is not likely to work either, and an ASV will be necessary.

I run my APAP machine in fixed pressure CPAP mode. I don't want the machine to be chasing central hypopneas, or adjusting pressure at all. All I want is a fixed pressure high enough to treat most OA events. That is one of the secrets in treating complex apnea with a CPAP or APAP in CPAP mode.

You are correct, and are probably referring to the work done by Robert Thomas, M.D., Associate Professor of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center. He has written an article in the blog section here.

Complex Sleep Apnea

A quote from the article:

"I also remember noting that bilevel positive airway pressure (BILEVEL) was often resulted in worse responses than continuous positive airway pressure (CPAP, including auto CPAP). In fact, in patients with NREM dominant sleep apnea, auto CPAPs seemed to “chase” changing breathing patterns with pressures that went up and down during sleep, resulting in even poorer results than use of fixed CPAP."

He also describes the experimental treatment which essentially reduces the mask ventilation to increase the CO2 levels.

Altitude can play a significant role in central and complex apnea. People living at higher elevations can have significant issues with central apnea. I worked with one poster here that had a permanent home at a lower elevation but vacationed at a high elevation lake in Mexico. His machine worked at home but not in Mexico with the same settings. My recollection is that he didn't want to keep changing his machine so he bought an AirCurve ASV.

I live at 2000 feet so not high altitude compared to places like Denver but I notice a significant lowering of AHI when I vacation for a couple of weeks at sea level. I am also convinced that my AHI also changes with weather here at home and suspect it is likely to be changes in atmospheric pressure.

One thing for sure. Complex apnea is complex!

Can't agree. I had treatment emergent complex apnea with a very high ratio of CA to OA events. A ResMed AirSense 10 AutoSet in fixed pressure CPAP mode works just fine for me. My total AHI over the last 285 days is 0.83. The CA component is still dominant at 0.52, compared to the obstructive index at 0.27. This compares very favourably to the total AHI of 3 to 5 I was getting in APAP mode. Now it may not work for every type of central apnea and complex apnea, but it does work for me

I think you are misunderstanding my point. I am not saying that ASV's don't work in treating central apnea and mixed apnea. Clearly they do. What I am saying is that with certain types of central apnea such as treatment emergent complex apnea, a simple CPAP can work well too, and an ASV is not necessary. And further if an APAP is not working well on treatment emergent complex apnea, then a move to a BiPAP may be a mistake. Anything that increases treatment pressure can make it worse. A change to fixed pressure CPAP mode may be more effective.

I see the use of CPAP, APAP, BiPAP, and ASV's a bit differently. Yes, the ASVs are the only ones that monitor each individual breath and provide pressure support on a breath by breath basis. There are some BiPAPs that detect absence of regular breaths, and provide longer term pressure support, and may do a timed backup pressure support mode (VAuto ResMed?). And not all CPAPS and APAPs can distinguish between central apnea events and take the appropriate action. CPAPs take no action on either type of event, and that is the correct action in the case of a central event. The ResMed and Phillips DreamStation APAPs can distinguish between CA and OA events and basically use the same method to do it. And, they both respond appropriately in most cases which is no pressure increase in response to a CA event. One issue with them is that they don't distinguish between central based hypopnea events and obstructive based hypopnea events. If one is having central based hypopnea and the machine responds with more pressure then the treatment induced type of central apnea is aggravated instead of corrected. BiPAP machines try to use more pressure support and that also can aggravate central apnea. For these reasons pressure induced central apnea may be best treated with a simple CPAP or APAP in fixed pressure CPAP mode.

There are some machines out there, and the F&P SleepStyle may still be one of them that do not have the capability to distinguish between the obstructive and central events. They are the worst machines of all to treat complex apnea with central apnea. They actually increase pressure in response to CA events and that is the worst possible thing to do. I dodged a bullet when I got my sleep study done. The clinic I used would only offer a SleepStyle and not a ResMed or DreamStation. That machine would not have worked for me in Auto mode, but it may have in CPAP mode. And to your original point of this post it makes you wonder why they would only offer one brand of machine. This same sleep clinic only offered my wife the ResMed S9 a couple of years earlier. What changed? More of a "kickback" on the F&P SleepStyle?

The article at this link gives a deep dive look at the technical differences between the popular machines. It is a bit dated but does include the ResMed A10 and For Her versions, so is not that old. The Respironics machine included is the System One Remstar Auto, which I believe now is the DreamStation Auto.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update

My only experience with Ontario comes from helping people out there through the forum, and both my wife's and my machine came from on line companies in Ontario. From what I understand there are two slightly different types of stores there. Some are qualified to OHIP standards and some are not. You may have to be a bricks and mortar store to qualify as a supplier of the OHIP paid machines. OHIP sets the price they will pay, so that kind of puts a ceiling on the prices charged in Ontario, which is a good thing. Some stores provide follow up assistance with the machine. Where my son got his machine in Ontario which I think was the same place my wife got hers does provide some follow up. Or, at least they promise it. I have checked my son's machine and they have never changed anything on it. The only changes are the ones I have made for him. I bought my machine at a different place that was on line only and they do not do follow up. They may in fact have the same owners as the storefront operation qualified to OHIP. They will do an initial set up based on your sleep study report, but that is it. I asked for my machines to be left as configured in the factory.

My only experience with the US DMEs is in helping people on the forum. It really does not sound like a good system at all, although I guess like Ontario it does provide machines without cost. These DME outlets seem to force patients to follow their procedures for machines depending on their assessed needs. In the worst case it seems one would have to be prescribed a fixed CPAP first along with the mandatory in lab titration study to set the pressure, then if that does not work, an Auto version, and if that does not work, then a BiPAP, and when that does not work on central apnea finally an ASV. And this is done despite the fact that the last time I checked an APAP machine is only $80 more expensive than a basic CPAP. And, there is no data to support that a BiPAP is more effective in treating central or mixed apnea than an APAP. It may in most cases be worse. Seems like a horrible waste of time and money.

There are some that advocate using home sleep studies, and immediately prescribing an APAP with no in lab testing or titration. This eliminates a lot of the expense. This is the way the system is going in Alberta. I know many people that get an APAP, and none of them actually go the route of an in lab sleep test, and just use a home test kit, no titration test, and then use an APAP in Auto. There are still in lab test facilities but they are suffering big time, and are not impressed with all the home study private companies that have popped up in Alberta. They are almost as many of them here now as there are pot retail shops! Perhaps that is because they pocket the $1900 profit on each machine they can get customers or the insurance company to pay for.

And then if APAP does not work as well as it should then there is the option to switch it into fixed CPAP mode and set the pressure at the 90% pressure level based on the experience in Auto mode. Some even advocate that as the best final solution especially for those that have central or complex apnea. That is where I am.

There are also now on line stores for CPAP machines and supplies in Alberta. I get some of my supplies there now as the delivery can be better, and prices sometimes are lower. One is a company called Sleep Yeti. I may buy my wife's replacement machine there if they ever get some stock... Right now like others they have nothing.

I don't think we have anything like the DME in Alberta. These sleep clinics are privately owned, and do the sleep testing and then sell you a machine. You are free to go to any one of them if your doctor gives you a referral.

There is something very fishy in the Canadian sleep clinic business at least in Alberta. Each province may be different. The standard practice here is for a clinic to offer a "free" sleep test, and if it indicates a need for a CPAP device they give you one on trial, again for free. But, when it comes time to get the machine, the cost is $2400 (prices from 3 years ago or so). However if you go to an on line supplier, the price for the same machine and mask etc is $800 with free shipping. So what does the full CPAP setup really cost? 500$? don't know, but it has to be around there. So this begs the question as to where the $1900 difference between the cost of the machine and the sleep clinic goes? Private insurance companies cover this $2400. What is even more puzzling is that my son had his insurance company agree to the $2400 for the sleep clinic package. Then when he found out from me that he could buy the ResMed AirSense 10 AutoSet machine full package for $800 plus $1200 for a second portable (Z1 Auto) machine, the insurance company agreed to pay for them both. That would suggest they are not getting a kickback from the sleep clinic or from ResMed. So perhaps it is really the Sleep Clinic that is making totally exorbitant profit of $1900 from each customer. And this is not just ResMed. I was offered a F&P SleepStyle machine (which I disliked) for the same $2400, and I know of others who got a DreamStation for the same $2400. Kind of puzzling...

What it makes me think is that the private insurance thing is a rip off. You are better just paying for your own machine and not paying for insurance at all. That is what my wife and I did. No coverage for CPAP so we bought our own for the $800 or so each price.

You may find this article in the blog section at MyApnea of interest. It is written by Robert Thomas, M.D., Associate Professor of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center. From this article and others, it seems that the body mainly uses CO2 in the blood not O2 to control breathing. Probably CO2 is more sensitive than O2 in determining whether we are breathing to fast or too slow. My theory in this whole issue of central and complex sleep apnea is that there may be a number of different root causes, like heart failure, drugs (opioids or similar), and altitude, but the problem manifests itself in a control system instability or failure. In the case of low blood circulation the system gets out of sync with breathing rate and CO2. Then it becomes like a poorly performing cruise control in a car. You hit a bit of a hill, the car slows down, and the cruise after a delay give the engine more gas. If this delay is too long then, you may be going down the other side of the hill by the time it gives more gas, and then the speed goes too high, starting the cycle all over again. I see this effect quite clearly in my SleepyHead graphs. An obstructive apnea event happens spontaneously, and like the hill in the cruise control analogy that starts an unstable control system response which then results in one or more central apnea events.

I have not heard of apnea during the day to be an issue, but a number have reported sleep onset apnea. But, I have never seen it documented on a SleepyHead or OSCAR graph. In your case I would be worried about apnea during sleep as I suspect during the day it may be unpleasant but is self correcting at some point. In any case here is a link to the article.

Complex Sleep Apnea - A Patient’s Introduction