Tidal Volume Drop

[MeWho]

I have been using a ResMed Airsense 10 for about 2 years. This spring, around April, I started feeling like the therapy wasn't as successful as it had been. I have ignored it for a long time because I wasn't in a seriously bad place, but I was feeling more tired that I had and feeling like something wasn't as good as it had been. There were no changes in my prescription and my machine is set to auto.

I finally downloaded SleepyHead to see if I could see a change, and at first I didn't see much until I looked at Tidal Volume. There is a noticeable change on a day in April when the tidal volume declined. I don't believe there were any equipment changes and I know there was no prescription change or other change under my control that could account for it. I wouldn't care too much about the change except that is coincides with the feelings I have of being under-treated compared to previously. I also thought I started noticing strange behavior on my device as it seems the auto-start doesn't work as well as it used to and it doesn't automatically shut off if I remove the mask.



Does anyone have any suggestions for investigating this further? Was there perhaps an update to the device that was pushed out over-the-air that might be causing my problems?

I would rather not return to the sleep doctor if I can do some simple machine diagnostics first. Any suggestions for things to look at would be appreciated.

[OkyDoky]

When did you change to the P10 and did you change the mask type in the settings?

[MeWho]

When did you change to the P10 and did you change the mask type in the settings?

I haven't changed anything about my equipment at all and have been using the nasal pillows, (That is the P10, correct?) since the beginning.

[LSAT]

I have been using a ResMed Airsense 10 for about 2 years. This spring, around April, I started feeling like the therapy wasn't as successful as it had been. I have ignored it for a long time because I wasn't in a seriously bad place, but I was feeling more tired that I had and feeling like something wasn't as good as it had been. There were no changes in my prescription and my machine is set to auto.

I finally downloaded SleepyHead to see if I could see a change, and at first I didn't see much until I looked at Tidal Volume. There is a noticeable change on a day in April when the tidal volume declined. I don't believe there were any equipment changes and I know there was no prescription change or other change under my control that could account for it. I wouldn't care too much about the change except that is coincides with the feelings I have of being under-treated compared to previously. I also thought I started noticing strange behavior on my device as it seems the auto-start doesn't work as well as it used to and it doesn't automatically shut off if I remove the mask.



Does anyone have any suggestions for investigating this further? Was there perhaps an update to the device that was pushed out over-the-air that might be causing my problems?

I would rather not return to the sleep doctor if I can do some simple machine diagnostics first. Any suggestions for things to look at would be appreciated.

If your machine is set on AUTO you are showing the wrong machine in your profile. You are showing the Airsense 10 CPAP where it should be Airsense 10 Autoset.

[MeWho]

If your machine is set on AUTO you are showing the wrong machine in your profile. You are showing the Airsense 10 CPAP where it should be Airsense 10 Autoset.

I think I have it set in my profile correctly. I definitely have the autoset and use it in the autoset mode (Does that make it an APAP? Still learning the lingo)

[Pugsy]

Does that make it an APAP?

Yes.
APAP is auto-adjusting positive airway pressure
CPAP is continuous positive airway pressure

An APAP is a cpap with an additional mode of operation where the pressure can auto adjust as needed.
So it has 2 modes...cpap and auto...like having 2 machines in one.
You can use an apap in cpap mode but a cpap machine only has one mode of operation..fixed pressure.

[Jay Aitchsee]

Tidal Volume is the volume of one breath. Average Tidal Volume is around 500ml. Your Average is a little difficult to see from the chart, but it looks to be a little higher than 500 prior to April and a little lower after for a median value (not average) over the period of 420. The maximum values are probably experienced while awake.
I can think of four things that might cause a reduction in Tidal Volume, but these are only guesses.
1. Decreased lung capacity (for some unknown reason).
2. An increase in Flow Limitaions.
3. Mouth Breathing. viewtopic.php?f=1&t=112758&p=1085906#p1085906 - Mouth breathing will cause an apparent decrease in tidal volume because the machine can't measure flow thru the mouth when using a nasal only mask.
4. Perhaps ill fitting, collapsing, or wrong sized pillows or a dirty mask exhaust vent. Did you change pillows around this time?

You might change the Y value scale of your Flow limitation chart to see if there is a corresponding increase. Check the leak graphic for an increase about that time which could signify mouth breathing. Look at the pressure graphic as well for a corresponding change in average pressure.
What has your AHI been doing over this period? Changes in total or type?
You might try changing your pillows and cleaning (requires a good stiff brush) the mask vent screen.

How about posting a few more Overview charts to include some of the things above as well as some representative Daily charts

Did you change beds, location or sleeping position?

[MeWho]

(edited to reduce image size)
Large image below of most of the relevant graphs. The leak rate went to near zero. I can't figure out how to get the flow rate as anything other than a day-by-day view, but just eyeballing the days before and after April 17th, it looks perhaps there is an increase in the overall flow limitations after the 17th. It is difficult to tell without any summary statistics. I tried exporting the data to CSV and doing some averages on the before and after summary statistics and got the following:



The AHI went way down, but that doesn't track with how I feel. I feel worse by a noticeable margin.

I looked back in my calendar to see what I was doing on that day, and it turns out I had gone out of town and had taken my device with me. I returned the night of the 17th, or perhaps the 16th, I can't quite remember, but I know I took the device with me. I returned to my normal bed, no changes or anything. I have been sleeping on the same mattress since 10/10/2015, so well before the change here. Is it possible I damages something moving my device that might cause this? I have disassembled and cleaned my machine many times since then and have traveled with it a few times, so I don't think I just put something together wrong. I have included a bigger screen shot of my data, but let me know if I can provide anything else that might help.

[Julie]

Just gaining a very small amount of weight can often make a surprising difference to how you feel, how your mask fits, and even your report.

[palerider]

if you want to, zip up your SD card and upload it to https://www.dropbox.com/request/0LalWvEsijRIgX8sdM7H and I'll see if I can find anything.

with what you've provided, the only thing I see is the leaks seem to have stopped, and maybe that was causing an issue before, and incorrect reporting.

[Jay Aitchsee]

Thanks for posting some additional charts, but those images are too large and the change period isn't displayed on my device without going to the source.

In my post above I listed some things that might cause a reduction in Tidal Volume, but after thinking about it, I'm guessing this is likely a mechanical thing, like a change in mask, rather than a physiological one. I think the sharp reduction in leak supports that. Are you sure you didn't change mask types about that time?

Further, I don't think the apparent reduction in Tidal Volume is necessarily a negative issue. Part of what makes the change look dramatic is the reduction in the maximum values. The maximums, which are two or three times normal average, represent very deep breaths which likely occur while awake or disturbed.

Waveforms may be included in the Overviews and Daily views by placing a check mark in the appropriate box under file/preferences/events and waveforms.

Daily View screen shots, one before and one after the date of change might be helpful.

Review these references for using sleepyhead and posting images.
https://sleep.tnet.com/resources/sleepyhead
https://sleep.tnet.com/resources/sleepyhead/shorganize
https://sleep.tnet.com/reference/tips/imgur
Imagur is used in these example, but the techniques apply similarly to other photo hosting sites.

Upload your card to pale rider and let him have a look.

Here's a smaller version of your image

[OkyDoky]

In my post above I listed some things that might cause a reduction in Tidal Volume, but after thinking about it, I'm guessing this is likely a mechanical thing, like a change in mask, rather than a physiological one. I think the sharp reduction in leak supports that. Are you sure you didn't change mask types about that time?

That was my thought also especially with the coexisting sharp decrease in the leaks.

Further, I don't think the apparent reduction in Tidal Volume is necessarily a negative issue. Part of what makes the change look dramatic is the reduction in the maximum values. The maximums, which are two or three times normal average, represent very deep breaths which likely occur while awake or disturbed.

My guess is that the leaks were causing disturbed sleep resulting in deep breaths making the maximum look much larger than now. With the leaks corrected there are less deep breaths making the total volume look less but is still probably normal.

The detailed screenshots will be interesting to see.

[MeWho]

Thanks for all the great suggestions. I am uploading my data now to PaleRider to see if there might be insights within. As some of you noted, the sharp drop in tidal volume, which also coincides my my subjective feeling of not resting as well and a more objective measure of more overall time spent in bed, indicates a few things. First is there was a change that was sudden, which wouldn't correlate with things like weight gain or other gradual changes. I was traveling that weekend and on my return home, the lower tidal volume and feelings of not getting sleep started, so it is possible that it was something about unpacking the machine after the trip. In particular, I may have swapped out the nose pillows and possibly the headgear, but it would have been for identical devices. Is it possible something is defective in the headgear? I have replaced the nose pillows multiple times since then, but I may be on the same headgear or maybe not, I can't be sure. I could have also given the machine a good cleaning and normal maintenance stuff as I unpacked.

I know that in the chart, the leaks went down after April 17th, and that would normally be a good thing, but I feel subjectively worse and I am sleeping longer after April 17th, so I believe the leaks going down is a byproduct of lower flow or pressure at my nose somehow. That might also explain the increased difficulty in the getting the machine to auto-start after April 17th.

I have added screen captures of the two days before the event and two days after the event for comparison in the below pictures. You can also download the full-res versions at the download links below that to see more detail.

April 12


April 16


Whatever happened, happened here

April 19


Feb 23


https://1drv.ms/i/s!Ako1_m9xdFg1uZhMFsXCN4O0-CXrKA

https://1drv.ms/i/s!Ako1_m9xdFg1uZhNZj4rpta3yAXTvQ

https://1drv.ms/i/s!Ako1_m9xdFg1uZhLvHABA8c5Jgsgyw

https://1drv.ms/i/s!Ako1_m9xdFg1uZhOdvY3tXySmYcSBA

[palerider]

well, I've got no clue. only that at 23:09 on april 18th, 2016, your breathing went from 460ml TV to 240ml TV... average. it was pretty consistent before, and pretty consistent after. why that happened, I've no clue.

as far as recent data, I'd suggest raising your minimum pressure to eight, or nine.

[Jay Aitchsee]

Same version of SleepyHead? Is this a For Her model Autoset?

Odd, that from PR's post, this change seems to have occurred during a session.

I think an average Tidal Volume of 240 mL is quite small compared to a normal of around 500mL. If my math is right, that would be the amount that might be expected for a person weighing around 75 lbs. (7ml/Kg). If the reading is correct, I don't know what it might mean physiologically.

Perhaps checking these results against ResScan wouldn't hurt, but I wouldn't really expect any difference.
You can get ResScan by following this link to ApneaBoard. You must register with ApneaBoard. Follow their instructions and a link will be sent by email.