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What causes this pattern of tidal volume?
What causes this pattern of tidal volume?
Hey guys, I'm posting this separately from my therapy thread so that more people with tidal volume issues click on the thread. I've been plagued by extremely poor sleep quality with fairly debilitating daytime symptoms and want some answers and solutions.

I wanted to know if anyone had tidal volume graphs that consistently (every night) stays stable for some period, then erratic, then stable again, as shown below:

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RE: What causes this pattern of tidal volume?
Did you notice any difference when trying nasal mask or it was pretty much the same?

I would be kind of curious to see if a cervical collar affects this at all. I have been wearing one due to a neck fracture and noticed it evened out some of my flow rate graphs (which is what is a mess in your case and what causes the TV chart to fluctuate). Can see my experience in the following thread.


It would be good to see your minute vent chart too. I assume your respiratory rate fluctuates in accordance with TV to maintain roughly same MV.

Edit: Oh yeah and one more thought in your case. I have never understood the TV fluctuation and high TV at the beginning of every night. It is almost like you are hyperventilating or something and it appears similar to some of these other fluctuating TV periods making me wonder if some of them are awake periods (think I mentioned that in your other thread already but might as well mention here too). A lot of people have a handful of high volume breaths when first starting the machine but yours is often exaggerated for some reason.
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RE: What causes this pattern of tidal volume?
I did try using the Fisher & Paykel Eson 2  Nasal mask last night with BreatheRight strips and mouth tape but genuinely felt like I was suffocating and switched to the f20 FFM. I'm going to try using the nasal mask after using Afrin tonight to see if Nasal breathing is plausible.

Here is the screenshot with minute vent as well:

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RE: What causes this pattern of tidal volume?
That is what I couldn't remember, the minute vent does fluctuate as well.

You can try a decongestant in order to test nasal mask but clearly that is not a long term solution. I know I mentioned Dymista to you, have the docs tried it? If it provides relief it would be better than a decongestant and can be used longer term (docs were pretty much going to leave me on it I believe). It works far better than either an antihistamine or steroid on their own. 

Your case is one that I believe is either not breathing related or CPAP/bilevel just doesn't seem to help that much (although you do seem to be doing better and more coherent in posting now, it just isn't clear if that improvement is because of CPAP use or all the other things you have done). 

ASV would be kind of interesting and potentially could combat these fluctuations but they are expensive machines and it would be an off label use. I know you somehow convinced doctor to get a bilevel but ASV would be even less likely and not guaranteed to solve the issue or symptoms. If you could just try one for a bit I would say go for it but I have a hard time recommending buying one out of pocket and hoping it will fix the issue. 

There was recently another member on here that ended up having surgery done and claimed it improved his breathing substantially but even more so than ASV I have a hard time recommending surgery. I think it can have its place and be beneficial in some cases but CPAP forums aren't the place to figure out if it will be beneficial for you. The problem is finding a good doctor that you can trust to diagnose what the issue is with tests, measurements, imaging etc and then a good surgeon that does a good quality job. Not sure if the best person to see is ENT, Orthodontist or if there is some other kind of doctor for that stuff but I think the key is trying to find someone that does sleep disordered breathing related surgeries as their primary occupation and see what they recommend if anything. If you do consider any surgeries definitely research it and potentially even get second opinions before diving in.
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RE: What causes this pattern of tidal volume?
If you're going to use a nasal spray, I really suggest using something like Flonase rather than Afrin. Don't get me wrong, Afrin is really amazing, but with it's renown rebound effect it can adversely affect you for several weeks. Flonase (fluticasone propionate) is well suited to countering the effects of inflammation and allergies. It takes a couple days to become fully effective, but can be used without rebound or adverse effects long-term. The problem with posting this as a new thread, is I have to go back to your previous thread to compare the tidal volume that is the subject of this discussion. The fact of the matter is that your tidal volume is higher (380) than in your previous thread where tidal volume is consistently 340 mL, and even minute vent is measuring higher at 6.38 L/min vs 5.88 or less L/min. So your perception is not reality. You may indeed be pulling harder to get the air you crave with this mask, but it has not reduced your respiratory volumes; apparently quite the opposite.
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RE: What causes this pattern of tidal volume?
What does your inspiration time chart look like? My tidal volume fluctuations look much like yours when my fitbit  indicates I'm awake and I think this is to be expected. It can also indicate extended periods of sleep/wake junk possibly accompanied by lucid dreaming although you should be aware of this. The inspiration time chart would also show even more dramatic fluctuations.
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RE: What causes this pattern of tidal volume?
To Sleeprider:

The screenshot I've posted was while I was using the F20 FFM after I switched to it 30 minutes after using the F&P nasal mask. I believe the increased median TV was a result of raising PS to 5.

I do have a Flonase prescription, but am currently off it to avoid the chance of developing Empty Nose Syndrome after my turbinectomy that I underwent at the end of August. I will restart it soon (or ask my ENT / Primary Care Physician about dymista) but want to confirm whether the nasal mask is effective before going back home (to a different country where I can't receive supplies) for the holidays.

I will be careful about my Afrin usage to avoid rebound congestion, and will only use it once tonight.

To Grandpapa:

While I do remember bits and pieces of a decent amount of my dreams, I don't believe I'm aware that I'm dreaming during those periods. 

To Geer:

What would be some possible causes for sleep issues besides breathing issues? I do remember saying that for my gender, height, and weight, my median Tidal Volume is abnormally small, although no one was told me that the median TV is the right statistic to consider. PLMs don't seem to be an issue according to my sleep study nor do I have any significant respiratory issues when awake. Most Neurological / Autoimmune disorders have been ruled out as well. And I'm skeptical about how mental health issues affect sleep this significantly. (I Believe poor sleep is the main contributor to my mental health issues)
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RE: What causes this pattern of tidal volume?
The ENT wanted you to go off Flonase or is that something you decided to do? I haven't heard of flonase causing empty nose syndrome and my ENT prescribed me to use a nasal steroid to help my nose heal after my septoplasty and turbinate reduction surgery so it just seems kind of counter intuitive. If you are just worried about empty nose syndrome for some reason I would say don't be, all your symptoms still point to nose being too full still. Dymista is leaps and bounds ahead of Flonase and the top recommendation for nonallergic rhinitis which is what I assume you have. If Flonase use wasn't providing you with clear airways than just tell your doctor that and that you heard Dymista might help more and see what he says.

My comment about not breathing related is because a lot of the symptoms you mention are not specific to sleep disordered breathing. I think there are tons of things that can cause these symptoms and some like say chronic fatigue syndrome and fibromyalgia don't have specific tests for. A lot of these cases aren't easy to figure out, like mine... 3 years in and still trying to figure things out...

Your case may be breathing related but if it is I don't think it is standard apnea/flabby skin that PAP pushes out of the way. I think it is nasal congestion, restricted airways, potentially small airway/bone structure etc (not entirely sure what your structure looks like though). Although some things point to breathing improving while on PAP your titration study also indicated no breathing issues which of course has me hesitant to believe they are the problem (albeit that was only one night of data).
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RE: What causes this pattern of tidal volume?
Hi AmirKas

Interesting observation and thank you for the question. Thought I would chip in my 2c worth.

As Geer1 mentioned we want to look at Tidal Volume(TV) together with Respiratory Rate(RR) and Minute Ventilation (MV)
TV x RR = MV. Ideally your body should regulate the two to give a relatively constant MV. There may be some lag as your body tries to adapt/catch up.

I have looked at my own Tidal Volumes (TV, but I label this as Vt) with interest.

My own TV is highest when I am awake or transitioning between sleep stages.

I find there is a correlation between Leaks and TV (or at any rate the TV that the ResMed machine is able to record.)

In your own chart of Dec 8th you will see wildly fluctuant TV associated with Events e.g. HA and flattened flow rates.
When your Flow Rate is stable so is your TV e.g. between 7:40 to 8:10 and 9:10 to 9:40.

I attach 3 things below that may be of interest and for further discussion.

In my night of Thu Dec 9th...


There is clearly lower TV when there is higher leak.
This is best seen in my graph between 00:15 and 01:00 where there is a large plateau leak and lower Tidal volume, below the Median.
Then from 01:30 to around 02:30 there are low leaks but higher TV, now above the Median.
However, your own leaks on the night of the 8th are really low, so this may not be applicable to you.

I am also seeing some correlation with the periods of Sleep transition recorded by my Garmin SQ but have no idea how accurate that is.
However, clearly when we dream, either in REM or non-REM, our breathing patterns will change, depending on the dream!

I have also been looking at my own data correlations this year and since switching back to my favourite P30i Mask since September (alas I have to accept some leaks).
My Pressure Support on the Vauto has been steady between 0.6 and 1.2 but mostly around 1.0.

There is a significant negative correlation between my Leaks and my TV. This means that for me, the higher the Leaks the lower the Median TV but also the 95 percentile TV: see the top 2 rows here in this image.

For my P30i-only data I note elsewhere that there is no correlation between Pressure Support and Median TV (+0.17) and 95% TV(+0.15).
However I am currently only using PS of around 1.0 and note you are at 5.0.  I suspect this would affect your own TV, as you have already hinted at. I wonder if this will accentuate the variation in TV we normally see.

In fact, for my full year-to-date data with F30i and P30i with PS/EPR ranging from 0-4.4 there is a strong positive correlation between PS/EPR and Med TV of 0.54 and 95%TV of 0.57. These are some of the highest (Pearson) correlations I have found in my data. See the first two rows here.

Also, for me there is clearly a lower Med TV with higher Flow Limitations (95FL vs Med TV = -0.4). This is not a factor on your chart of the 8th because it shows really low FL.

So in summary there are many factors that may affect our TV within the apnoea/SDB environment, including our machine settings, our own Flow limitations and so on.

I merely include these as my own observations and for discussion.

However I fully agree with Geer1 that there may of course be reasons that lie outside of your Sleep Environment and if you have sufficient concerns (e.g. ongoing fatigue or low pO2 levels as two simple examples) you would want to consider discussing this with your own health care provider/physician.

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RE: What causes this pattern of tidal volume?
Severe Apnea those are some interesting findings backing up how a FFM is less effective treatment in your case (results being PS dependent).

I believe this to be the case with Amirkas as well but unfortunately nasal congestion makes it tough for him to use a nasal mask.
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