Central Detection Driving Me Nuts!!

[Reznik]

Hi Guys,

I know that the gurus around here all recommend the smart machines, but I just wanted to take a minute to see if anyone else is having the same problem that I do with them.

All of the smart machines have some mechanism for detecting central apneas.  Resmed uses the Forced Oscillation Technique, which blows a 4hz pulse of 1cm air at you starting four seconds after any apnea and continuing until you start breathing again.  Respironics send a 2cm pulse starting ten seconds after any apnea and continuing for 2 seconds.

Both of these technologies wakes me up repeatedly, particularly as I drift off to sleep and about 6 hours later.  Even when I don't wake up, I still feel miserable in the morning.  I raised this issue with my doctor, but he was under the impression that central apnea detection is only used when the machines are in auto-titrating mode.  He was wrong, as both Resmed and Respironics use central detection in their non-brick machines even when they are set to CPAP mode. 

The only way to get a Resmed or Respironics CPAP that doesn't do central detection is to buy the base model CPAP machine, which have no detailed data, and which the gurus here describe as "bricks."  Interestingly, you can also buy the AirCurve 10S or VAUTO, and set it to S mode with easy-breathe off, and you'll get no central detection but you will get detailed data reporting.  I've now tried a machine with no central detection and I've found a night and day difference.  I wake up far less frequently and I feel better in the morning.  

I honestly can't help but wonder whether people who are unable to adapt to CPAP are failing because the central detection methods are disturbing their sleep???  

Is it really wise to recommend that people buy the smart machines given this potential side effect?

Does anyone else find these central apnea detections disturbing??

[Apnea Infant]

Hi Reznik

Good to read you again.

You clearly are very sensitive to pressure increases to be able to sense these pulses. Also perhaps you know about them and thus are aware of them. I cannot say my awakenings are due to central apnea detection or other but I do not have total undisturbed sleep often. I can count on one hand how often I have slept solidly through the night. That said, short awakenings do not keep me up much. I fall asleep again pretty quickly.

Sorry this is not really answering your question.

[Walla Walla]

Is it really wise to recommend that people buy the smart machines given this potential side effect?

Compared to the alternative of recommending a brick? Yes I'd say it's wise to recommend a full data machine. Are you sure it's the testing of the event that wakes you up and not the event itself?

[kiwii]

...Resmed uses the Forced Oscillation Technique, which blows a 4hz pulse of 1cm air at you starting four seconds after any apnea and continuing until you start breathing again.

Is this true? I'm using the ResMed AirCurve 10 VAuto, and have woken up to find that I am not inhaling. The machine is doing nothing, as far as I can tell. There is certainly no increase in pressure until I start breathing again. This is why my doctor(s) are recommending a machine that has a backup rate for me.
What you have written is what I expected from my machine -- some way to 'make' me breath if I had stopped. Mine does not do that.

[Grandpapa-G]

Hi Reznik,
Are your apneas that cause the problem scored as centrals or obstructive? When I have an arousal (enter a period of sleep / wake junk) I have many events that are scored as centrals and I can see the 4 herz oscillation on the graphs - but I certainly not able to feel anything. I have even tried to feel this when I am wide awake and resting (while using the machine) but I feel nothing as the 4 Hz oscillations start. However if, after 5-6 hours of sleep, I have an arousal I do have a great deal of trouble falling back asleep - which I have come to accept as normal. During these periods of sleep wake junk my respiration rate drops to 9-10 / minute (from 12-13 during sleep) which triggers these false centrals. I suppose it is possible that on some subconscious level my body does respond to the oscillations.

[Sleeprider]

Maybe we could work on resolving the events that result in the machine testing for an open airway, then the FOT pulse should not be a problem?

[Reznik]

Thank you to everyone who responded to far.  I'm going to respond to each of you, below:

... perhaps you know about them and thus are aware of them. I cannot say my awakenings are due to central apnea detection or other but I do not have total undisturbed sleep often. ...

I wasn't aware of the pulsing and the FOT until they started to wake me up.  However, I suspect that they can cause arousals and/or micro-arousals which are not enough to wake me up, but which are enough disturb my sleep and make it less restful.

Compared to the alternative of recommending a brick? Yes I'd say it's wise to recommend a full data machine. Are you sure it's the testing of the event that wakes you up and not the event itself?

I'm almost certain.  I've tried a machine that doesn't do central detection and I wake up feeling refreshed.  When I use a machine that has central apnea detection, I wake up feeling worse than I would have had I not used a CPAP at all.

If the net effect is that the machine makes a person less rested than when they weren't using a CPAP at all, then I have to disagree.  Most people will never review the data.  But, if they are having arousals and micro-arousals from the FOT, then they probably get better sleep and better treatment with a brick.

...Resmed uses the Forced Oscillation Technique, which blows a 4hz pulse of 1cm air at you starting four seconds after any apnea and continuing until you start breathing again.

Is this true? I'm using the ResMed AirCurve 10 VAuto, and have woken up to find that I am not inhaling. The machine is doing nothing, as far as I can tell. There is certainly no increase in pressure until I start breathing again. This is why my doctor(s) are recommending a machine that has a backup rate for me.
What you have written is what I expected from my machine -- some way to 'make' me breath if I had stopped. Mine does not do that.

The FOT pulses are NOT enough to stimulate a breath.  If you want a machine that's going to force you to breath when you stop breathing, you need a machine with a timed backup (AirCurve 10 ST) or an ASV model (AirCurve 10 ASV).  Both are VERY expenses.

Hi Reznik,
Are your apneas that cause the problem scored as centrals or obstructive? When I have an arousal (enter a period of sleep / wake junk) I have many events that are scored as centrals and I can see the 4 herz oscillation on the graphs - but I certainly not able to feel anything.  I have even tried to feel this when I am wide awake and resting (while using the machine) but I feel nothing as the 4 Hz oscillations start.  However if, after 5-6 hours of sleep, I have an arousal I do have a great deal of trouble falling back asleep - which I have come to accept as normal.  During these periods of sleep wake junk my respiration rate drops to 9-10 / minute (from 12-13 during sleep) which triggers these false centrals. I suppose it is possible that on some subconscious level my body does respond to the oscillations.

Any kind of apnea will cause the machine to go into FOT.  

FYI- You can have arousals that you are not aware of.  They're not enough to wake you up, but enough to disturb your sleep.  If you've ever gently tapped your spouse to get her to roll over when she was snoring, you should know what I'm talking about.  What do you think would happen to her sleep if you were doing that 3-5 times per hour?  

Also, note that the Resmed machines will not do FOT when they are in a timed ramp or during the first 30 seconds or so of therapy with no ramp.  So, if you're trying to feel the pulses, you need to turn off the ramp, and use the machine for about 30 seconds.  Then hold your breath while you're lying down and not moving around.  You'll feel them.

Maybe we could work on resolving the events that result in the machine testing for an open airway, then the FOT pulse should not be a problem?

My AHI is between 1.8 and 3, which is very good and certainly better than without a CPAP.  I'm definitely working on fine tuning it to get the AHI down to 0.  Part of my problem is that, like many new CPAP users, I'm experiencing treatment emergent central sleep apneas ("TECSA").  The TECSA will likely go away on its own over time without me doing anything.  But, as long as the machine keeps arousing me everytime one happens, I'm not going to be able to get a good night's sleep.

[SideSleeper]

I got my CA's down to none (most of the time) by dropping my exhale support (Flex on my PR machine) to 1 from the 3 that was in my original prescription. Is this EPR on ResMed machines? I seem to be able to live with the pulses on my machine, thankfully!

[Grandpapa-G]

[quote pid='247876' dateline='1520191913']


Any kind of apnea will cause the machine to go into FOT.  

FYI- You can have arousals that you are not aware of.  They're not enough to wake you up, but enough to disturb your sleep.  If you've ever gently tapped your spouse to get her to roll over when she was snoring, you should know what I'm talking about.  What do you think would happen to her sleep if you were doing that 3-5 times per hour?  

Also, note that the Resmed machines will not do FOT when they are in a timed ramp or during the first 30 seconds or so of therapy with no ramp.  So, if you're trying to feel the pulses, you need to turn off the ramp, and use the machine for about 30 seconds.  Then hold your breath while you're lying down and not moving around.  You'll feel them.

[/quote]

I guess I wasn't clear on my previous reply. Some months ago I had read a previous post (your's?) about being able to feel these pulses so I tried relaxing , while awake for 15 minutes or so, and I certainly saw some centrals scored and some 4 Hz ripples on the graphs - but I felt absolutely nothing. I did hold my breath but that was not necessary. 
Six months after starting CPAP therapy I had a second overnight sleep test at the sleep clinic with a BiPap machine. Although I did not sleep much the doc said I had no apneas but many times when the time between subsequent inhales exceeded 10 seconds and would have been interpreted by a cpap machine as apneas.  As far as I know I can Identify most if not all of my arousal periods (over 1 minute or so in duration) by inspecting my flow limit graph which flat-lines (at 0.0) during these periods.

[Reznik]

I guess I wasn't clear on my previous reply. Some months ago I had read a previous post (your's?) about being able to feel these pulses so I tried relaxing , while awake for 15 minutes or so, and I certainly saw some centrals scored and some 4 Hz ripples on the graphs - but I felt absolutely nothing. I did hold my breath but that was not necessary. 
Six months after starting CPAP therapy I had a second overnight sleep test at the sleep clinic with a BiPap machine. Although I did not sleep much the doc said I had no apneas but many times when the time between subsequent inhales exceeded 10 seconds and would have been interpreted by a cpap machine as apneas.  As far as I know I can Identify most if not all of my arousal periods (over 1 minute or so in duration) by inspecting my flow limit graph which flat-lines (at 0.0) during these periods.

If you want to feel the pulses, you must ensure that your machine is not in a timed ramp period, and then you must stop breathing.  Just relaxing while you're awake won't cause the pulsing to occur.  Also, you really have to be lying down.  If you're sitting up, your body is doing a lot of work to hold your head and torse in the area, and you're much less likely to notice the pulsing.  

My flow limit graph goes to 0.0 all the time without an arousal, so I'm not sure that you can use that as a measure of arousal.  You really need something to monitor brainwaves in order to find an arousal.