Sierra

A post from Ace copied and pasted here:

"Sierra, I am a 52 year old man that was diagnosed with obstructive apnea. I also have astma, but not central apnea. I use the RESMED airsense 10 since one year approximately. The healthcare detected high blood pressure cause of apnea. And since I got the apap treatment the blood pressure has gone down. But now when I went through a 24 hour test I've noticed that the blood pressure is high during awakening. I've also noticed that I can wake up a couple of times catching my breath........ when I'm half awake, so to speak, it's almost like I have central apnea. This is quite scary, when you find yourself not even atempting to breathe. What sleeptech is writing is not to be taken lightly. The industry itself will never bring up matters like this. Obviously they want to develop their products to be as good as possible to be competitive and sell more. But during development there will be issues like this. And these "issues" can actually cost lives(!) Now to my point. I've tried with decreasing the EPR-level from the preset level 3 to 2, 1 and finally the last weeks turning it off. When the EPR turned off completely, I've noticed a very big difference. I breathe much better and sleeps better. My natural brething (respiratory effort) is normal again. If the EPR-funtion (Expiratory Pressure Relief) affects and increases the CO² levels creating central apnea we should never even consider trying out the EPR(!) As sleeptech mentioned: "should be avoided in almost every instance." Concering CO²-levels and central apnea: "I have recorded evidence of this happening." "Where I work, we only ever allow our patients to use EPR or C-Flex if they have had a sleep study with it and we can verify that it is not causing any harm. Otherwise we do not use it at all. I can think of fewer than 5 people who have actually had some benefit from using EPR/C-Flex in all my years of being a sleep tech." Please take his warnings seriously. (For comfort, setting the ramp with EPR is of no harm obviously.)"

My reply to your post:

Based on my personal experience when I awaken during the night short of air, I believe I have had an apnea. It could be either central or obstructive. I unfortunately suffer from more central apnea events than obstructive, and increased pressure is of no benefit in reducing central events.

I have also adjusted EPR from none to 3 on numerous occasions. As I said in my post, it has had no repeatable impact on my frequency of central apnea. But also as I said I can get the same apnea normalization with less maximum mask pressure when EPR is turned off. On that part I agree with Sleeptech. It has some negative impacts but I would suggest it is in mask pressure not any impact on central apnea frequency.

With respect to impact on oxygen and CO2 levels I think you have to put it in perspective. We are talking about a pressure increase of 3 cm of water. Yes, that means more oxygen will go into the lungs, but the question is whether or not 3 cm is significant. I won't bore you with the math, but if you do it the atmospheric air pressure when the weather changes from a low pressure formation to a high pressure formation, the pressure in CPAP units changes by about 35 cm of water. That is a factor more than 10 times higher than turning EPR on or off at a setting of 3 cm. My conclusion is that 3 cm is not significant in the scheme of things. Also remember that standard atmospheric pressure is about 1030 cm of water in absolute units. A change of 3 divided by 1030 results in a very small percentage change.

You mentioned that you gained some benefit by turning EPR off. Again without going through my previous post again, I think that is quite possible in that depending on how your machine is set up turning EPR off may reduce the frequency of obstructive apnea. Have you quantified what your before and after central and obstructive apnea frequency was? I find one needs to document at least a month's worth of data to determine what the change had been.

Another thing to consider is that one of the treatments for higher than 5 AHI due to central apnea is to use a BiPAP machine. A BiPAP really only differs from an APAP in that it can use an EPR of higher than 3 cm. Yes it is called pressure support but it is really the same thing -- a split in the IPAP and EPAP pressures. And central apnea is actually treated by using a higher than 3 cm split in the pressures. Some question the effectiveness of it, but it is done. I know because I suffer from central apnea and I have investigated all options to deal with it including a BiPAP and an ASV machine.

So I will say again that I agree with Sleeptech in that there are some downsides to using EPR for someone who is mainly suffering from obstructive apnea, but causing central apnea is not a very likely one. It certainly has not been my personal observation although I wish it was. I don't think you will find credible sources elsewhere that suggest it causes central apnea either. If there are, I have missed them. If you have them, then I certainly would be interested in looking at them.

I am 68 years old and have mixed sleep apnea (obstructive and central). I am also Type 2 diabetic. But, I am not a doctor and cannot provide you with any kind of diagnosis. That said I have suffered from time to time from some of the same things you describe.

Getting dizzy when standing up is called orthostatic hypotension. I am aware of it as it is a symptom of diabetic neurophathy, and that I have to be observant of. It can also be caused by low blood pressure and many other conditions. It can be a side effect of blood pressure medications. Headaches, waking up to pee several times a night, and night sweats are symptoms of diabetes and high or low blood sugar. I have experienced them personally. Blood sugar variations can cause similar symptoms that you describe like feeling dizzy or drunk. My suggestion is to be sure to ask your doctor to test you for diabetes if that has not already been done. You are a little old to have juvenile type 1 diabetes, and not old enough to be a typical type 2, but in my opinion as a diabetic, you have enough symptoms to be tested. There are three tests for diabetes and ideally you want them all done. One is an overnight fasting blood glucose test, another is the oral glucose tolerance test (OGTT), and the last is the AIC test which estimates blood glucose over the last three months. All can be done in one lab visit. Having all three tests done is much more conclusive than relying on one single test.

Like diabetes you are not a likely candidate for sleep apnea based on your age and weight. However getting a sleep study test done is a good idea. It should be quite revealing as to whether or not apnea could be an issue.

Hope that helps some...

I took the risk. It seemed pretty simple and legit.

Wilson, I am just another user of the AirSense 10 AutoSet machine, and not a professional. So don't take this as professional advice. It is simply that of another user.

1. Yes, your APAP is doing a pretty good job in reducing an AHI of 61 down to a residual AHI of 2.5. An AHI in the 0-5 range is considered normal. That said, an APAP is normally more effective in reducing obstructive apnea than it is in reducing central apnea. What portion of that 2.5 AHI is obstructive and what part is hypopnea? In my experience I think hypopnea can be related to obstructive apnea, or central apnea. So, I always look at the hypopnea component as a bit of a question mark.

2. An APAP tries to normalize obstructive apnea and obstructive hypopnea by keeping the airway open with air pressure. That physically usually works, but it can have some side effects. Mask discomfort is usually the worst one. I have tried 5 different masks and finally settled on a nasal pillow mask. That said masks are very personal and I really can't give you any advice other than to keep trying ones to the extent you can. What I can say is that about the second worst sleep I ever got was my first night with an APAP. The worst night was when I did the at home sleep study. Both terrible sleeps. But, I have slowly gotten used to wearing a CPAP at night and the benefits are now outweighing the initial discomfort and the effect it had on my sleep quality. In short, give it some time. And if a mask is not working for you, ask your supplier to suggest another. You also mention that you have obstructive apnea that is not well controlled with pressure. That is unusual. You may want to ask your general practitioner to refer you to a specialist to see if there are other reasons for obstruction. In my understanding of risk factors, your age and BMI should not put you at high risk of OSA, so there may very well be another reason.

Some general comments. You said your AHI went up to as high as 129 at certain pressures. I would ask your sleep doctor or sleep tech what the reason for that could be. In some people central apnea goes up when pressure goes up. It would be helpful to know if that applies to you. At the same time you could ask if it is a pressure in the 10-20 range that you have been prescribed, and could be a contributor to your residual AHI if the machine runs you all the way up to 20 cm.

Many people who suffer from apnea track their results on SleepyHead. It can be very informative as to what may be affecting your sleep quality, and how well the machine is working for you. If you are interested I can post some more information on it. In my opinion as a user, the ResMed supplied MyAir applications is not very good. SleepyHead is much better.

Hope that helps some. Any questions, just ask.

Sleeptech makes a lot of good comments and is obviously very experienced. However, this is one subject where I partly agree, but not 100%. I believe the main problem with EPR or Flex is that it reduces EPAP (exhale pressure). Apnea can occur on the exhale as well as on the inhale. So if you have an APAP that is set up and working reasonable well, and then turn on EPR at 3, then it will reduce your EPAP by 3 cm. That is most likely to increase apnea, which will in turn cause the APAP to increase the treatment pressure. The net result will be an increase in maximum mask pressure, which may cause discomfort or mask leaks. But, your apnea incidence is likely to remain unchanged albeit with a higher IPAP (inhale pressure). A problem can occur if your maximum pressure is set such that the APAP cannot compensate for the EPR. Then apnea incidence is likely to go up.

I would suggest it is controversial whether or not EPR, and especially Flex actually increases oxygen uptake and as a result may cause some central apnea. I have tried with and without, and can see little difference. This said there are some instances where EPR or Pressure Support in a BiPAP can actually help with the breathing effort, and may reduce central apnea. I believe this only works when the body is slowly reducing breathing effort, and the APAP or BiPAP somewhat compensates for this by switching quickly back and forth between IPAP and EPAP pressures. It is kind of like artificial breathing, but the effect is pretty modest. It is more effective in a BiPAP where the pressure support can be increased above the 3 cm limit of EPR.

What does this mean? For me the increase in IPAP and thus mask pressure is real when I use EPR. I can reduce maximum pressure by about 2 cm when EPR of 3 is turned off. But, especially when going to sleep there is a definite comfort benefit in using EPR. What I do is use the AirSense 10's auto ramp feature to set a comfortable start pressure, and set the EPR at 3, but for the ramp only. After I go to sleep and the ramp ends, the EPR ends. Pressure then ramps up to my minimum, and I don't notice it when I am sleeping.

So in short I think EPR is good for ramp only for most users, but it is not a big risk to use it full time especially if your maximum pressure is low. But if you want to minimize mask pressure, then turn it off. Treatment of central apnea is more complex, and EPR or Pressure Support may help if carefully tuned.

You also may want to prepare yourself for a diagnosis of Mild Apnea. In Alberta CPAP treatment is considered the gold standard for mild apnea, but a dental appliance may be an option. They tend to be quite expensive if not covered by insurance. As I understand it BC Health does not cover the cost of a CPAP if you are in the Mild category (AHI 5-15). They only cover for Moderate (AHI 15-30), or severe (>30). If in this category, I would inquire about options to do a CPAP trial.

That sounds good. You should get a very good indication from an overnight study as to where you stand with the degree and type of apnea you have (or don't have!).

This time I would insist on a copy of the written report of the study findings. It is your right to get it. It is also your right to get copies of the two at home studies you have already had. See the link below and this excerpt from it.

"Enduring Access Are physicians required to give patients access to or copies of their medical records?  Patients own the information in their medical records, as affirmed by the Supreme Court of Canada in its decision in McInerney v. MacDonald in 1992.  Subject to bullet point 3, patients are entitled to examine and receive a complete copy of their medical record, which includes any records created by other physicians, and this access must be provided to the patient upon request (usually within 30 business days).  The duty to provide a patient with access to the record may vary according to the applicable law, any relevant agreement with a third party and the consent of the individual. Physicians must ensure that they know the applicable legislation and rules with respect to a patient’s right of access. Physicians are encouraged to seek the guidance of the CMPA, or their legal counsel, if unsure about how to respond to a request for access. Section 29 of the Personal Information Protection Act (PIPA) states that a physician must generally respond to a patient’s request for that information within 30 business days."

Practice Standards - Medical Records - British Columbia

The ResMed machines show the actual pressure plus the minimum and maximum pressures of an APAP at startup. The DreamStation only shows the current actual pressure. That pressure may be the minimum pressure or it may be the ramp start pressure, depending on how the machine is set up.

I agree that a BiPAP is a bit more complex than an APAP, and one needs to understand what they are doing and why when making adjustments.

The situation may vary widely depending on the region one lives in, but having access to a professional and one that actually is knowledgeable is not a given. I know from your comments here that you are very knowledgeable, but not all sleep technicians are. The one I had told me that the CPAP machine she was recommending would cure my diabetes, which I have had for 20 years. Ok, sure... And then the machine she recommended does not even detect central apnea which is my main problem. I left her and the machine behind and went on my own.

I think the other part of the issue is that sleep clinics make their money doing sleep studies and selling machines (may vary by region), and not by doing followup and adjustments for existing CPAP users. My son has an AirSense 10 and bought it from a source that said they would monitor and adjust his setting remotely. He has had it for nearly 3 years, and I looked at the machine history a few weeks back, and it had never been adjusted once from the initial setup which was not very good.

My conclusion from my experience, my wife's experience, my son's experience, and that of a friend, is that clinic follow up is poor to non existent. I think a user has two choices if they want the best results from their CPAP or BiPAP. One is to use SleepyHead, and learn what is good performance for your machine, and when it is not, then be persistent with your supplier to make changes. And that may not be so easy if they will not monitor your results remotely, and even more difficult if they want to do subsequent titration tests, instead of reviewing your machine data and just doing an adjustment. The issue is that doing adjustments is time consuming and often ends up being iterative. In this posters case, I would expect 3-4 adjustments of IPAP Max will be required to get optimum results. Then if central apnea frequency is not acceptable, then possibly even more adjustments of the pressure support may be needed. It takes time and not all clinics are prepared to do it. The user of course has nothing but time.

So the other option is for the user to educate themselves, do their own monitoring, and make their own adjustments. In my view those users in the end will have the very best results from their machine. Nobody has more interest in getting things right, than the actual user. But, one has to take the time to become informed.

Just my view. I like to provide the information and some advice, and let the user decide what they want to do.

If your machine is set up properly you should not have to do that. The machine should immediately feel comfortable and breathing effort should be unrestricted like you are wearing no mask at all. The trick on an AirSense 10 is to set a minimum pressure of 7 cm for example, use the auto ramp feature with the start pressure also at 7 cm, set EPR to 3 cm and for Ramp only.

When set up like this the machine will immediately give you 7 cm on inhale, which most find comfortable. On exhale pressure will go down to 4 cm which is the lowest possible pressure for the machine. It will stay at those pressures until the machine senses you have fallen asleep. Then it will ramp pressure up to your machine minimum, which may be the same 7 cm in this example, and stop the EPR. Inhale and exhale will be the same. This gives you up to 30 minutes to fall asleep and get used to the machine.

Here is a SleepyHead screen shot showing what that looks like. I use pressures a little higher than in my example. Ramp start of 8.4 cm and a minimum treatment pressure of 11.6 cm. At 11:24 I started the machine. About 10 minutes later at 11:35 the machine decides I am asleep and starts the ramp up. By 11:38 or over 3 minutes the ramp is complete, the EPR reduction on inhale is stopped, and I go to a constant 11.6 cm, until the machine decides I need more. Works really well for me.