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Central Apnea question
#11
(05-03-2014, 09:48 AM)jbuchanan6196 Wrote: what are the small blue dots that don't rise or have a number above them?
Hypopnea
ResScan does not shows the number (duration in seconds) but SleepyHead does
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#12
(05-03-2014, 09:10 AM)jbuchanan6196 Wrote: Sorry I left out some info! AHI has been low, like around 0.5, I don't think its ever gotten up to 2.0 which I know is great. I'm fairly new to therapy, my machine reads: Days>4 hours = 49/66, so about 9 weeks.

You're in wonderful shape. I wouldn't worry about a thing. Having days where you don't feel rested is normal.

Remember that the only reason we undergo CPAP therapy is so that we can enjoy the time we have when we're awake. I recommend you focus on that. The data you're collecting indicates that your therapy is working for you.

Assuming, of course, that your leak rate is under control. Look for periods of time where your leak graph spikes. If those are occurring they could be a sign that you're mouth-leaking, which would also interfere with the quality of your sleep. If so, a chin strap is recommended.

Do you have a sleep doc who's keen to look at your data?
Sleepster
Apnea Board Moderator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#13
(05-03-2014, 09:10 AM)jbuchanan6196 Wrote: Sorry I left out some info! AHI has been low, like around 0.5, I don't think its ever gotten up to 2.0 which I know is great. I'm fairly new to therapy, my machine reads: Days>4 hours = 49/66, so about 9 weeks. That includes the couple weeks I was on Auto and the period I was trying to get used to it.

Then there is nothing to worry about and very little you can do about it anyway.

There are 3 types of events:

Obstructive Apnea -- the machine realizes you aren't breathing and determines there is an obstruction.

Clear Airway (when MAY be a Central Apnea) -- where you stop breathing but the machine cannot find an obstruction. You just stop breathing.

Hypopnea -- you are breathing, but your volume is reduced to some significant percentage and the machine thinks you aren't getting enough air/oxygen. (The Resmed machine and both software programs tend to score these too often in my opinion. You can see this by looking at the detail of your flow in SleepyHead or Rescan.)

The simpler types of machines - CPAP and APAP (like your AutoSet) -- don't deal with CAs.

Most of us like to "play the game" of seeking "The 0.0 AHI" but really anything consistently below 5 is considered fully treated and if you keep it below 1 (or even 2) that's about as good as anyone an expect.

There ARE ways to reduce CAs that don't involve changing machines, but they are hit or miss and likely only worth pursuing if you recognize that trying to lower a 1 or 2 AHI is MERELY PLAYING A GAME.

I like to play so here are some ways to do that (only read the following if you realize that this is JUST A GAME):

1) Turn off or turn down EPR -- for some people this will lower CAs. I turned mine off, didn't miss it, but ended up turing it back to 1. Never FELT a difference but it seemed to buy me a 1/2 point to turn it off and maybe 1/4 (or less) to use 1.

2) Restrict your airflow a little -- using the SMALL pillows in my AirFit P10, seem to drop my CAs about a 1/4 point.

3) Find the perfect range on your APAP (I put this last because theoretically you doctor is the only one who is 'supposed' to order the settings changed although I started setting my machine DAY 1 before the FIRST SESSION.

IF you are doing this, first get your lower number up to cover almost all the OAs, THEN if you can get your Upper Number to trim just a LITTLE from your max or 95% pressure you MIGHT gain a little benefit in CAs.

Likely your BEST BET would actually be looking at your lifestyle, things like drugs and alcohol use etc.; this might lower your CAs or other apnea even more.

Remember at these levels it is JUST A GAME.

I was pulling an occasional 1 to 2 after getting my treatment stabilized in the first week, but in the last 20 days, my max is 0.7, and 0.1 to 0.5 represents the majority with a rare 0.0 or 0.6/0.7.

Getting rid of the AHI readings near and greater than 1 was about playing those games.



Sweet Dreams,

HerbM
Sleep study AHI: 49 RDI: 60 -- APAP 10-11 w/AHI: 1.5 avg for 7-days (up due likely to hip replacement recovery)

"We can all breathe together or we will all suffocate alone."
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#14
(05-03-2014, 03:45 PM)herbm Wrote:
(05-03-2014, 09:10 AM)jbuchanan6196 Wrote: Sorry I left out some info! AHI has been low, like around 0.5, I don't think its ever gotten up to 2.0 which I know is great. I'm fairly new to therapy, my machine reads: Days>4 hours = 49/66, so about 9 weeks. That includes the couple weeks I was on Auto and the period I was trying to get used to it.

Then there is nothing to worry about and very little you can do about it anyway.

There are 3 types of events:

Obstructive Apnea -- the machine realizes you aren't breathing and determines there is an obstruction.

Clear Airway (when MAY be a Central Apnea) -- where you stop breathing but the machine cannot find an obstruction. You just stop breathing.

Hypopnea -- you are breathing, but your volume is reduced to some significant percentage and the machine thinks you aren't getting enough air/oxygen. (The Resmed machine and both software programs tend to score these too often in my opinion. You can see this by looking at the detail of your flow in SleepyHead or Rescan.)

The simpler types of machines - CPAP and APAP (like your AutoSet) -- don't deal with CAs.

Most of us like to "play the game" of seeking "The 0.0 AHI" but really anything consistently below 5 is considered fully treated and if you keep it below 1 (or even 2) that's about as good as anyone an expect.

There ARE ways to reduce CAs that don't involve changing machines, but they are hit or miss and likely only worth pursuing if you recognize that trying to lower a 1 or 2 AHI is MERELY PLAYING A GAME.

I like to play so here are some ways to do that (only read the following if you realize that this is JUST A GAME):

1) Turn off or turn down EPR -- for some people this will lower you CAs. I turned mine off, didn't miss it, but ended up turing it back to 1. Never FELT a difference but it seemed to buy me a 1/2 point to turn it off and maybe 1/4 (or less) to use 1.

2) Restrict your airflow a little -- using the SMALL pillows in my AirFit P10, seem to drop my CAs about a 1/4 point.

3) Find the perfect range on your APAP (I put this last because theoretically you doctor is the only one who is 'supposed' to order the settings changed although I started setting my machine DAY 1 before the FIRST SESSION.

IF you are doing this, first get your lower number up to cover almost all the OAs, THEN if you can get your Upper Number to trim just a LITTLE from your max or 95% pressure you MIGHT gain a little benefit in CAs.

Likely your BEST BET would actually be looking at your lifestyle, things like drugs and alcohol use etc.; this might lower your CAs or other apnea even more.

Remember at these levels it is JUST A GAME.

I was pulling an occasional 1 to 2 after getting my treatment stabilized in the first week, but in the last 20 days, my max is 0.7, and 0.1 to 0.5 represents the majority with a rare 0.0 or 0.6/0.7.

Getting rid of the AHI readings near and greater than 1 was about playing those games.

I like the point about it being a game. Both myself and my sleep doc consider me well treated if my AHI is below '10'. Why so high? Because my untreated OSA was so severe! Yes, lower *is* better, but I so rarely get below 5, it's just a random event.

Some folks *like* chasing numbers, and there is nothing wrong with that as long as you understand both what you're doing, and why you are doing it.

There are so many outside variables to consider:
  • Drugs - script or otherwise
  • Booze - a single beer or a lot
  • Food - within 3hrs of bedtime
  • Drink - other than water within 3hrs of bedtime
  • Stress
  • Exercise - too much, or too little
  • Mood
  • Change in perscription meds
  • Different pillow
  • Too hot, or too cold
  • Humidity set wrong
  • Mask change

The list really can go on and on. How bout too much or not enough sleep even?

Two things to remember?
(1) Low leaks, and AHI below 5 = success, PERIOD!
(2) If you make any changes, do so very slowly, one at a time, over a period of weeks, not days.
*I* am not a DOCTOR or any type of Health Care Professional.  My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
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#15
(05-03-2014, 02:00 PM)zonk Wrote:
(05-03-2014, 09:48 AM)jbuchanan6196 Wrote: what are the small blue dots that don't rise or have a number above them?
Hypopnea
ResScan does not shows the number (duration in seconds) but SleepyHead does

In Rescan, Select the day, view Detailed Graphs, look on the "Events" chart, the little number above each event is the time in seconds of the event.

There is very little that Rescan can do that SleepyHead cannot and vice versa -- but each makes SOME THINGS quite a bit easier.

The main advantages of Rescan are the many reporting options and the ability to use MERELY the summary data if you forget to put your card back in the machine during a sleep session -- SleepyHead won't see that session (or perhaps entire day if you forget overnight).

Sweet Dreams,

HerbM
Sleep study AHI: 49 RDI: 60 -- APAP 10-11 w/AHI: 1.5 avg for 7-days (up due likely to hip replacement recovery)

"We can all breathe together or we will all suffocate alone."
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#16
(05-02-2014, 06:11 PM)jbuchanan6196 Wrote: For example, last night it showed I had 7 centrals while the night before just I had one. ...
My body definitely feels like I had that many apneas today more than other days, even with using CPAP.

If you slept 7 hrs the 7 CA events would represent a Central Apnea Index of 1.0, which I think the health profession in the USA would consider completely negligible, especially since all were fairly short.

However, if you continue to definitely feel worse after nights when larger numbers of central events occur, you definitely should not ignore these events. Keep an eye on them and see what you can come up with, to minimize them.


(05-02-2014, 06:50 PM)SnuffySleeper Wrote: Don't worry too much about central apneas in rescan/sleepyhead as these programs can only use air resistance recorded in wavforms to measure such events.

This in turn gives false positives as all the machine knows is that it sent a puff of air and never got anything back. This can be caused by many things, like changing position, breathing goes out of sync for a bit, mask leaked for a little bit..etc.....

Actually, I think ResMed's Forced Oscillation Technique (FOT) is quite accurate, unless unintentional leak is too high (more than 24 Liters per minute) or is varying quickly.

Please see "Central Sleep Apnea Detection and the Enhanced AutoSet Algorithm" white paper; the link is at the bottom of the following ResMed webpage:

http://www.resmed.com/uk/products/s9_ser...nc=dealers


(05-02-2014, 06:50 PM)SnuffySleeper Wrote: My observation as I am a low pressure guy like you, is that resscan/sleepyhead reports CA events that are really hypopneas (shallow breathing) but because the pressure is low it doesn't have as much air resistance to read and marks it a central apnea.

As far as I know, it is excessive Leak or quickly varying Leak, not low or high pressure, which limits the accuracy of ResMed's central apnea detection algorithm.


(05-02-2014, 08:12 PM)jbuchanan6196 Wrote: I was taken off AutoPap when they determined that a straight pressure of 7 was effective for me. I just went through some of the data and noticed the median was more around 8-9. I may try to bump it up a notch.

If a long term average of the nightly Median Pressure was 8-9 during your APAP trial, then 7 would probably have been lower than optimal as a fixed CPAP setting. I doubt it, but maybe your doctor or therapist was giving you time to adjust to the pressure and was planning to increase your pressure in future, after watching the data for a while. If using a fixed CPAP pressure, I think somewhere around the 95 percentile APAP pressure would be more appropriate, or possibly higher, unless problems appeared like aerophagia or headache or hearing/dizziness issues or excessive central apneas, or excessive daytime sleepiness.

Further, if using the machine in CPAP mode (a fixed pressure all night), for some patients changing the amount of EPR (Exhalation Pressure Relief) can affect treatment efficacy, so ideally the APAP trial would be repeated using the new EPR setting. Having an APAP machine allows this re-titration to be done easily and without extra cost, merely by changing the operating mode of the machine to APAP for a time. For some patients who are on a fixed-pressure machine, increasing the EPR setting (which decreases EPAP, the pressure during exhalation) may tend to allow more obstructive apneas to occur unless the Pressure setting is raised an equal amount to compensate, to raise the EPAP back to the previously titrated setting.


(05-02-2014, 11:50 PM)herbm Wrote: BTW: You can also get these by just holding your breath while turning over ...

Whenever we "hold" our breath I think our airway tends to get closed off, making this effectively obstructive. When we stop breathing while turning over, rather than this mimicking a central apnea, I suspect we tend to create a brief obstruction which usually is not scored by the machine (because it lasts less than 10 seconds).


(05-03-2014, 12:15 AM)Sleepster Wrote: Are you new to CPAP therapy? If so, that is most likely the cause, and they will soon fade away. Your body is not used all the extra oxygen you're supplying, and those elevated oxygen levels trick your brain into thinking you don't need to breathe.

I've heard that usually the frequency of central apnea events decreases during the initial weeks or months of CPAP therapy as we become accustomed to CPAP therapy, as we become accustomed to the changed level of CO2 in our blood.


(05-03-2014, 12:15 AM)Sleepster Wrote:
Quote:However, some nights they are more frequent than others. For example, last night it showed I had 7 centrals while the night before just I had one. So is there any reason that these apneas occur more frequently some nights than others? I'm wondering what caused me to have more last night than previous nights.

Nothing is causing this, it's just a natural variation. It's like asking why it rains more on some days than others. That's just the way it is.

I agree with Sleepster that a variation of 1 per night compared to 7 per night may simply be natural variation, especially since both numbers are still very low and are usually considered insignificant.

At the same time, many things can affect the frequency of central apnea events. For example: how many hours we are sleeping, what time we go to bed, stress and anxiety, common non-prescription medications, changes in diet and exercise, developing or recovering from anemia, developing or recovering from heart conditions, changes in what time we drink caffeinated drinks, etc., all these things may have an influence.

Take care,
--- Vaughn

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#17
(05-03-2014, 06:31 PM)vsheline Wrote: Actually, I think ResMed's Forced Oscillation Technique (FOT) is quite accurate, unless unintentional leak is too high (more than 24 Liters per minute) or is varying quickly.

24L is the amount of leaks that can happen before the therapy is negatively impacted, meaning when it starts to affect CM h2o pressure.

Resmed likes to toot their own horn but my own experience I had tons of CA events, and I was worried and brought it up to my doctor. We compared the sleepyhead data I brought in with the sleep study that was done, all the "CA" events my s9/sleepyhead was reporting were actually hypopnea events. Knowing that it uses air resistance to measure the events the logic is the more pressure, the more data it has to analyze. I upped my pressure from 8 to 10 just to see what would happen, low and behold all my CA events in sleepyhead turned to Hyponeas and it was more inline with my sleep study data.


My Doctor said it's best not to worry about the "type" of event because the Cpap machine can just guess with an algorithm. The cpap data is just meant for overall trends to see how your therapy is going, it's not meant to identify single events with accuracy although it tries.

When taking data into sleepyhead you can actually zoom in on the wavform of each event (can't do that in resscan as far as I know) and see that there are A LOT of false positives the algorithm identifies. If the cpap machines were that accurate we would have no need for sleep studies Wink

That's why in sleep studies you usually have a camera on you, electrodes and o2 meter. As each event is gone through meticulously by a person (my sleep lab has 5 employees that just mark sleep studies all day everyday) and identified to an exact science. Which a single algorithm just can't do, but who knows, maybe in the future it will.

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#18
(05-03-2014, 09:48 AM)jbuchanan6196 Wrote: Also, a LITTLE off topic but something else I just noticed:
When looking at detailed data in ResScan under Events, I understand that a RED tick is an obstructive apnea and BLACK/WHITE tick is central. Well, what are the small blue dots that don't rise or have a number above them? Is is something that is to short to pick up? Different type of disturbance?

I know I'm full of questions but remember I'm still a newbie ;-)

The blue dots are hypopneas - periods when your breathing reduces but does not stop. It's typically a 40 or 50% reduction in airflow (depending on which machine / doctor you use). Although they are not as serious as apneas (some air is getting through) they are still undesirable and count towards the AHI score (that's what the H in AHI stands for).
DeepBreathing
Apnea Board Moderator
www.ApneaBoard.com


Bed

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#19
(05-03-2014, 07:13 PM)SnuffySleeper Wrote: Resmed likes to toot their own horn but my own experience I had tons of CA events, and I was worried and brought it up to my doctor. We compared the sleepyhead data I brought in with the sleep study that was done, all the "CA" events my s9/sleepyhead was reporting were actually hypopnea events.

The data was collected by the S9 during your sleep study?

The S9 has a low-inertia flow rate sensor, and it has a pressure sensor. The same is true of all good CPAP machines. It's these two sensors that collect all the data used to make the determination of whether an event is an OA, CA, or hypopnea. During a pause a breathing pressure pulses are sent in an attempt to determine if your airway is open or closed. During a hypopnea your airway is somewhere between open and closed, so I can see why the machine might erroneously determine that your airway is clear when in fact it's partially blocked. In a sleep study a chest belt is used to determine if you're making an effort to breathe during the event.

If you stop breathing and you expend no effort as indicated by the chest belt, that's a true central apnea. All a CPAP machine can do is determine if you're having a clear-airway apnea. Both are referred to as CA's, and it's common in the jargon of the industry to simply refeer to them as "centrals".

None of this matters if your leak rate is too high, because then the CPAP machine can't accurately determine anything about the status of your airway.
Sleepster
Apnea Board Moderator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#20
(05-03-2014, 08:54 PM)Sleepster Wrote:
(05-03-2014, 07:13 PM)SnuffySleeper Wrote: Resmed likes to toot their own horn but my own experience I had tons of CA events, and I was worried and brought it up to my doctor. We compared the sleepyhead data I brought in with the sleep study that was done, all the "CA" events my s9/sleepyhead was reporting were actually hypopnea events.

The data was collected by the S9 during your sleep study?


No the sleepyhead data was from my s9 at home, and we compared it with my sleep study data.

The general overview is the machines know "something" happened and tries to guess. As you said they measure air resistance through censors recorded as wavforms, but that dosen't tell the whole story. My doctor just ignored the single events From the cpap machine and gets a sleep study done which is gone over by his trained staff meticoulsy instead of an algorithm doing it.

Cpap machines can't tell what stage of sleep you"re in either, they can't even tell if your awake and jogging. Which makes their guess at what kind of event not that reliable, but of course it's great for a general overview and knowing how the therapy is going.
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