Just got Encore - Have Central Apenas

[mikeandtina]

Greetings!

I've just got Encore Viewer and am looking at the daily detailed information. What I have noticed is that my CA (Clear Airway Apnea - which I believe are also called "Centrals") occur more frequently than my Obstructed Airway Apneas. Both are probably both considered low, but I always seem to feel much better when my total AHI numbers are 2.5 or less. I'm 5'5" and weigh 135lbs. so maybe they bother me more since I'm not carrying alot of extra weight -- I don't know just a guess.

I am concerned because every night I have central apneas - they can range from 1.0 to 4.0 a night. Should I be concerned? My obstructed airway apneas range from 0.1 to 1.4. My doctor didn't mention it at my last appointment so perhaps it is nothing to worry about. But I would feel more assured hearing the opinion of the experienced CPAP'ers on the list.

Also, any information on what causes central apneas would appreciated.

Thank you!
Tina

[JohnBFisher]

... I've just got Encore Viewer and am looking at the daily detailed information. ...

That's a good thing to do to keep an eye on your own therapy ... I honestly think an active participation helps you more than anyone.

... What I have noticed is that my CA (Clear Airway Apnea - which I believe are also called "Centrals") occur more frequently than my Obstructed Airway Apneas. Both are probably both considered low ... I am concerned because every night I have central apneas - they can range from 1.0 to 4.0 a night. Should I be concerned? My obstructed airway apneas range from 0.1 to 1.4. My doctor didn't mention it at my last appointment so perhaps it is nothing to worry about. But I would feel more assured hearing the opinion of the experienced CPAP'ers on the list. ...

Of course, just remember that while I've had the chance over 20 years to learn about sleep and apnea (obstructive and central), there is no way I (or almost any of us) would substitute for your doctor. So, take what we say with a lick of salt!

Your doctor probably did not mention it for one of two reasons (or both). First, let's assume you sleep only six hours per night. An CA score of 4 with an OA score of 2 (being generous) is 6 total for 6 hours. That gives you an AI of only 1. That is, 6 apneas (obstructive and central) divided by 6 hours is 1 apnea per hour (on average). If your AHI goes over that, it means the rest of the AHI score is hypopneas - which is not as bad for you as apneas. Oh, it will disrupt your sleep, but many doctors discount *some* hypopneas.

So, with an Apnea Index (AI) that's less than 5, your apnea is well controlled.

The other reason might be that central apneas often cluster. That cluster tends to come when you transition to or from sleep. During that transition central apneas are normal and NOT considered during a sleep study. Unfortunately, your xPAP device can not determine if this is the case, so scores them regardless.

So, if you have apneas during the transition to or from sleep, it would be considered normal - and not mentioned by your doctor.

Either way, the number of central apneas per night is very low and well within "normal" range.

However, having said that, I do want to comment that you mention you feel better when your AHI score is above 2.5. That makes me think you might have more hypopneas than anything. You might want to see if something will help reduce that. For example, increasing the height of your head sometimes helps. Or perhaps bumping up your pressure by a notch. You get the idea. Don't over do it. But a little bit of careful tinkering might be a way to see if you can keep your numbers consistently lower.

... Also, any information on what causes central apneas would appreciated. ...

Tina, there are three basic different causes of central sleep apneas.

First, it appears the chemoreceptors that determine the amount of CO2 in the blood can be damaged / "set too high". Often if someone has severe sleep apnea for a long time they develop problems with gauging the correct amount of CO2 in the blood.

Second, someone with cardiovascular problems (especially with the heart) develops problems that lead to the a waxing and waning (increase then decrease) of respiration. This is known as Cheyne-Stokes Respiration (CSR) that often occurs in someone that has congestive heart failure and other heart related injury.

Third, some people develop problems with their brain stem and or the central nervous system, which controls respiration. For example, I have a condition known as Sporadic OPCA. It impacts my brain stem and results in depressed respiration. I need a special machine that acts as a ventilator when I fail to breathe normally. By sustaining my breathing, it helps restart my respiration without repetitive undershoot / overshoot.

In all three situations, the body initially fails to register the build up of CO2. It is actually that build up of CO2 that changes the blood chemistry (makes it more acidic) that drives our respiration. This is the undershoot cycle. That is, the body fails to properly breathe to maintain the proper CO2 levels in the blood. Then the body finally recognizes the increase in CO2. It tends to over compensate. This is the overshoot side of the cycle. The body hyperventilates and blows off too much CO2. And by blowing off too much CO2, the respirator drive is depressed and it sets up the next repeat of the cycle. And the cycle repeats over and over and over and over ...

To address this, when breathing falls behind (the projected volume of the next breath does not meet the moving average of the past three minutes), then an Adaptive Servo-Ventilation (ASV) system helps sustain ventilation. That is, by increasing the pressure to 25 to 30cm H2O, it helps move some of the CO2 out of the blood stream and allow some O2 to enter. This helps break the constant undershoot / overshoot cycle. The machine only intervenes when it projects the respiration will not meet that moving average. Thus, it is not a full ventilator, but it is much more than a "simple" BiLevel machine.

Hope that helps you understand this. However, in summary, you don't have much to worry about from the central apneas / clear airway events. Of course, as I mentioned, if you can reduce the hypopneas, then it appears it will help you.

[mikeandtina]

Thanks for your extensive response; I appreciate your effort in order to help me!

I’m glad to hear that my central apnea number is very low – and even within a normal range. I will try the elevating-the-pillow trick and bump up my lower pressure number by .5. I actually tried it tonight but for some reason cannot get to sleep – it’s almost 3:00 am!

Thanks for the education on central apneas. I have never heard of Sporadic OPCA, but thank goodness you have a machine that can help you deal with this problem. It sounds much more serious than your typical apneas. I didn’t know that CO2 drives our breathing; but it makes perfect sense. I did have undiagnosed apnea for 6+ years, but with my low centrals my chemoreceptors are hopefully not damaged.

Thank you again for your kindness!

[JDS74]

To elaborate a little on what John said about the CO2 level receptor in your brain. There is a second and different one for O2. When you are awake, the O2 sensor governs breathing, when asleep, the CO2 one governs. When transitioning between awake and asleep, both are used and if they don't exactly correspond, you get central apneas because the blood level if O2 is higher than the O2 sensor trigger point while the CO2 blood level is below the CO2 trigger point. In that range, no breaths are triggered and you oscillate between these two points until you are actually asleep and the CO2 sensor takes control.

You take a breath ( or several ) and the O2 level gets above the keep-on-breathing value and the CO2 levels falls below the CO2 trigger point - then the impulse to breath stops. Now the O2 level starts to fall. As the O2 level falls and the CO2 level rises you wait until the CO2 level gets high enough and you breath again. It's during this interval that the O2 level is above your O2 trigger point while the CO2 level is below the CO2 trigger point that centrals occur. The farther apart these to points are, the longer the period of central apneas will continue until control is finally switched to the CO2 sensor completely and your brain ignores the O2 level.

[JohnBFisher]

... I have never heard of Sporadic OPCA, but thank goodness you have a machine that can help you deal with this problem. It sounds much more serious than your typical apneas. ...

I am happy to help others. I've had a lot of 'fun' along the way. I figure that helping others helps bring meaning to my own experience. And if it helps others better manage their health, then my 'adventure' is worthwhile.

I am not surprised that you had not heard of my condition. Sporadic Olivopontocerebellar Atrophy (OPCA) is rarer than MS or ALS or ... The incidence rate of it is about one person is 100,000. It sometimes progresses into an uglier condition known as Multiple Systems Atrophy (MSA). I am showing signs of developing problems with my autonomic nervous system that might indicate my situation is headed toward MSA.

And you are right. Before I was put on an ASV unit, during that transition to or from sleep, I would stop breathing for more than a minute at a time. My bilevel machine would cut off if it did not detect breathing after one minute. The assumption by the engineers was that the patient must have take off the mask if there was no breathing. Well, it would cut off time after time after time. As you can imagine, I would awaken in the morning with HORRIBLE headaches. My blood pressure was out of control. And I used Ibuprofen for the headaches (as well as the aches and pains). Unfortunately, the bottles do not include a warning that high blood pressure and Ibuprofen causes kidney damage. Arrgh!

As JDS74 implies, that transition time (to or from sleep) can be difficult. If there are problems with the central nervous system (as is my case with problems with my brain stem), that transition gets downright dicey. The ASV machine was a godsend. Without it, I do not think I would be alive now.

So, I spend my time trying to help others avoid the same situation. And I also try to help educate folks like you who might be worried, but don't (from the numbers) have to worry. Knowledge is a powerful and helpful tool.

[JohnBFisher]

... To elaborate a little on what John said about ...

That's a great explanation! Thank you.

In fact, I think I will use the Hallmark style of blog posting ... "When you care enough to steal the very best!"

[mikeandtina]

Have you found anyone else on the list have OPCA? I hope you are able to find people who can help you, too; but thank goodness you are here to help those of us with just regualar apneas. I hope you have not had kidney damage from the Ibuprofen, and that your headaches are controlled.

Take care and be well!

Tina

[JohnBFisher]

Have you found anyone else on the list have OPCA? I hope you are able to find people who can help you, too; but thank goodness you are here to help those of us with just regualar apneas. I hope you have not had kidney damage from the Ibuprofen, and that your headaches are controlled.

Take care and be well!

Tina

Tina, thank you for your concern. I appreciate it.

Nope. No one (that I know of) has OPCA here. However, over at the National Ataxia Foundation (NAF) there are others with similar issues. They have a Facebook page on which I participate. And being a proactive sort of person, I am helping start a local support group in my state. During our first meeting I met several other folks with similar problems. So, I'm not alone and can find others who have similar issues (so I can find out what type of walkers work best ... or how to handle swallowing problems ... or speech problems ... or ... you get the idea). Sharing our experiences helps everyone.

Unfortunately, I did have some kidney damage. That's why I try to caution others about it. However, it's not severe and as long as my blood pressure remains stable, it should not advance (or at least only very slowly). So far over the past two years it has been stable or improved slightly. However, due to my diabetes, sleep apnea, kidney disease, ataxia, I decided it is important to have a MedicAlert bracelet. I want it to help talk for me when I can not. A friend's mother was recently treated for hospital caused drug overdose ... they failed to take into account that she had kidney disease when they administered opiate based pain medicine ... I'm hoping the MedicAlert bracelet will help emergency personnel remember that my body functions are not "normal".

And the ASV unit is a godsend! No more morning headaches. I dream again. And I feel rested in the morning. When I went in for the ASV titration, the sleep technologist warned me that a lot of people have problems adjusting to how an ASV works. Well, once I experienced the machine taking over for me when I stop breathing, I was hooked. It's REALLY reassuring to know that I can just "let go" and fall asleep.

In fact, I can normally tell when my body senses that I will have a bad night of sleep. Somehow, I subconsciously sense little clues that warn me of problems. I first consciously notice it when I realize that I am reluctant to go to sleep. It's a sign that I have to consciously step into the situation and go to sleep, knowing the machine will help.

[mikeandtina]

http://www.livestrong.com/article/13174 ... y-support/
http://www.livestrong.com/article/23174 ... m_medium=3

Hi, John,

Glad that you are feeling well and have your medical problems under control.
I don't know if you are interested in alternative medicine,but here are some links for diet and herb-related kidney support.

Thanks again for your help.

Tina