general questions/therapy

[1speechpick]

What is considered to be a "normal" minute vent value?

There's a very wide range of what constitutes "normal".
It varies widely due to sex, height, weight, body build, etc.
https://en.wikipedia.org/wiki/Minute_ventilation

In terms of what you see on the cpap software data it really isn't a data point that we normally worry about from the regular cpap machines.
Only important when someone is on a real ventilator where the machine is actually forcing a targeted amount of air movement.

Thanks for your response, Pugsy! I noticed last night my minute vent ranged from 3-4 (I have small frame, normal BMI, 5' 4' height, age mid 50s). The tidal volume was normal. Is 3-4 low for a minute vent?

I forgot to add "I'm a female "

[Pugsy]

It's probably normal for you. I am small female myself (not quite 5 ft tall) and 69 yrs of young. My minute ventilation numbers have always averaged on the "low" side but it's normal for me.
Especially if someone tends to be a more shallow breather vs big breath person. Weight also impacts things. People who are obese tend to be more shallow breathers.

Unless someone has hypoventilation syndrome...you can google it....doesn't mean much.
Usually if someone has a problem with adequate ventilation they and their doctor are already aware of it because of the other stuff that points to some sort of respiratory issue.

Best thing to do if you see one of the lung function/respiratory numbers on the software data that might concern you is to just ask your doctor about them. I don't even bother with any of the lung function/respiratory numbers on the software data because I know that the range of "normal" is so varied that going by just a number doesn't mean much.

[1speechpick]

It's probably normal for you. I am small female myself (not quite 5 ft tall) and 69 yrs of young. My minute ventilation numbers have always averaged on the "low" side but it's normal for me.
Especially if someone tends to be a more shallow breather vs big breath person. Weight also impacts things. People who are obese tend to be more shallow breathers.

Unless someone has hypoventilation syndrome...you can google it....doesn't mean much.
Usually if someone has a problem with adequate ventilation they and their doctor are already aware of it because of the other stuff that points to some sort of respiratory issue.

Best thing to do if you see one of the lung function/respiratory numbers on the software data that might concern you is to just ask your doctor about them. I don't even bother with any of the lung function/respiratory numbers on the software data because I know that the range of "normal" is so varied that going by just a number doesn't mean much.

Thanks Pugsy! Does shallow breathing generally create higher minute vent values?

[Pugsy]

Does shallow breathing generally create higher minute vent values?

No. The opposite.

[1speechpick]

It's probably normal for you. I am small female myself (not quite 5 ft tall) and 69 yrs of young. My minute ventilation numbers have always averaged on the "low" side but it's normal for me.
Especially if someone tends to be a more shallow breather vs big breath person. Weight also impacts things. People who are obese tend to be more shallow breathers.

Unless someone has hypoventilation syndrome...you can google it....doesn't mean much.
Usually if someone has a problem with adequate ventilation they and their doctor are already aware of it because of the other stuff that points to some sort of respiratory issue.

Best thing to do if you see one of the lung function/respiratory numbers on the software data that might concern you is to just ask your doctor about them. I don't even bother with any of the lung function/respiratory numbers on the software data because I know that the range of "normal" is so varied that going by just a number doesn't mean much.

Hi Pugsy: Are you willing to say what your minute vent numbers average? If not, I totally understand. Also, do pressure and/or flow limitations (from nasal congestion) affect the minute vent value? Thank you!

[Pugsy]

My minute vent numbers are normal for me and that's really all that matters.
If you are concerned about your numbers for you....then you really need to talk to your doctor.
Am I at the low end of the "normal" spectrum for the general population??? Probably but then I am tiny person with small lungs so those small lungs aren't expected to move as much air volume as a larger person.

do pressure and/or flow limitations (from nasal congestion) affect the minute vent value?

I wouldn't think so. Minute vent is nothing more than lung function and nasal issues shouldn't affect actual lung function and pressure itself doesn't either. All the pressure will do is hold the airway open and prevent tissue collapse.
Pressure doesn't affect how much air you move. At least not with these machines because they can't go high enough or fast enough to affect real lung function. Now those specialized high end machines where the docs can actually set for a certain ventilation rate or function are a different story but you aren't using one of those machines.

If you think your lungs aren't normal or respiratory system is compromised then you need to have a chat with your doctor and have the special tests that can be done to really measure lung function.
We can't really diagnose lung function issues by the numbers these machines give us. They were never designed for that sort of reporting. We just can't make any sort of determination for lung issues based on a couple of numbers.

[1speechpick]

Thanks Pugsy! My guess is that I'm in a similar situation...small frame, small lungs, smaller gas exchange...totally normal for us. I looked back at some of my old Oscar charts and my minute vent is similar, no matter what mask, flow limitations, or pressure I had at the time. I do have very, very mild asthma but it is very well controlled with minimal medication. I'm certain it's normal for me. You really know your stuff, Pugsy!! I can't thank you and the forum members enough for wealth of information you've shared!

[1speechpick]

I just don't understand some of these sleep physicians. My doc is adamant about me being at a CPAP pressure of 4. I understand my doc doesn't want the pressure to get too high because I've been having middle ear fluid and pressure, and too high of pressure gives me more centrals...but a level of 4? Last night, I vaguely recall waking up gasping for air in the middle of the night. I called the RT at my CPAP DME, and they were about as unhelpful as the doc.

Now, I'm wondering...could too low of pressure and gasping for air be causing the aerophagia I'm having?

Also, could too low of pressure cause the RERAs?

I've attached my chart from last night. I think it's time for me to turn on the Auto Set tonight. Any advice or input about my chart would be appreciated. Thank you.

[1speechpick]

I'm about 5 weeks into CPAP therapy, and have had multiple issues getting started. Thanks to the suggestions from you all, most issues are now tolerable, and my AHI is almost always under 5 (except when I wear a full face mask, which is still a mystery as to why the AHI increases with FFM, even with more pressure).

The monster I still haven't been able to solve is aerophagia. Aerophagia made its debut initially a few weeks ago. I started using Tagamet and/or Pepcid before bed (along with no eating 2 hours before bed) and that seemed to get things under control for a while. Now unfortunately for the past 4 days, the aerophagia is back with a vengeance. I've read up on the CPAP Wiki/aerophagia.

I've also spent some time reviewing aerophagia posts (using the search bar). Here's what I have tried the past few days that hasn't worked: elevating the head of bed. cervical collar, changing sleeping positions, varying the pressures a bit, and changing my nasal mask. I'm bummed because I feel like I've made good progress with so many of the other aspects of CPAP, but the aerophagia is really holding me back from being successful and tolerating CPAP. Does anyone have any other tips to get rid of this monster? I'm surprised it went away with meds for a while, and now has returned.

[Pugsy]

AHI is almost always under 5 (except when I wear a full face mask, which is still a mystery as to why the AHI increases with FFM, even with more pressure).

My personal thoughts on why some people who go to a full face mask after using a nasal mask and the FFM user experience is a lot higher AHI or marked increase in pressure needs is because of what the FFM itself does to the airway with the way it has to be anchored on the face.
Specifically the lower strap on most FFM...it tends to pull the jaw back just a little (sometimes a lot depending on how tight someone cranks it down) and when pulled back the airway gets more restricted/smaller and/or it becomes difficult for the cpap machine to hold the airway open and prevent airway collapses/apnea events. Sometimes a LOT more pressure is needed to prevent those collapses...and sometimes just a little more. Probably going to vary a lot between people simply because people vary a lot.

I think if they could ever come up with a full face mask that didn't use lower strap or lower jaw anchoring points that we wouldn't see such a difference in AHI or pressure needs.

All things being equal FFM use shouldn't make a difference but because of how the FFM anchors and seals with that lower strap pulling the jaw back ever so slightly...all things aren't equal.
It is what it is and quite common and just something you have to accept and move on if you want to use a FFM.
Normally we would say just increase the pressure even more but with the aerophagia monster trying to sneak in we can't really go down that road. Not to mention I am not so sure that the jaw altering the airway isn't also maybe causing potential for feeding the aerophagia monster....just something you have to accept and make a compromise because really bad aerophagia can make us miserable and more miserable than the slightly higher AHI might make us.
Sometimes we just have to make compromises between 2 devils and choose the lessor of the 2 devils.

Just my opinion of course but it does make some logical sense. Put that full face mask on and watch how the lower strap pulls the jaw back a bit.

[1speechpick]

AHI is almost always under 5 (except when I wear a full face mask, which is still a mystery as to why the AHI increases with FFM, even with more pressure).

My personal thoughts on why some people who go to a full face mask after using a nasal mask and the FFM user experience is a lot higher AHI or marked increase in pressure needs is because of what the FFM itself does to the airway with the way it has to be anchored on the face.
Specifically the lower strap on most FFM...it tends to pull the jaw back just a little (sometimes a lot depending on how tight someone cranks it down) and when pulled back the airway gets more restricted/smaller and/or it becomes difficult for the cpap machine to hold the airway open and prevent airway collapses/apnea events. Sometimes a LOT more pressure is needed to prevent those collapses...and sometimes just a little more. Probably going to vary a lot between people simply because people vary a lot.

I think if they could ever come up with a full face mask that didn't use lower strap or lower jaw anchoring points that we wouldn't see such a difference in AHI or pressure needs.

All things being equal FFM use shouldn't make a difference but because of how the FFM anchors and seals with that lower strap pulling the jaw back ever so slightly...all things aren't equal.
It is what it is and quite common and just something you have to accept and move on if you want to use a FFM.
Normally we would say just increase the pressure even more but with the aerophagia monster trying to sneak in we can't really go down that road. Not to mention I am not so sure that the jaw altering the airway isn't also maybe causing potential for feeding the aerophagia monster....just something you have to accept and make a compromise because really bad aerophagia can make us miserable and more miserable than the slightly higher AHI might make us.
Sometimes we just have to make compromises between 2 devils and choose the lessor of the 2 devils.

Just my opinion of course but it does make some logical sense. Put that full face mask on and watch how the lower strap pulls the jaw back a bit.

Thanks Pugsy! I completely agree this is likely what is happening with the FFM in my case. It's the only thing that makes sense, as with all the other nasal masks the AHI is well controlled. Last night I used the FFM (I bumped up the pressure 1 cm) with an AHI of 21 (very few were centrals). And the med flow limitations were .95% (which I assume is significant?). This has been a pattern for me.

I did forget to change the mask setting from nasal to FFM last night. Does that make much of a difference?

Does aerophagia ever just disappear on its own? Or am I missing a management technique?

[Pugsy]

Most people I know of who need more pressure when they use a FFM will need at least 3 cm more pressure.

Forgetting to change the mask type setting doesn't really hurt much of anything. It might affect the reported leak numbers a bit but it isn't the cause of the higher AHI.

As for the aerophagia thing....some people find it fades away with time and others find they have it forever.....just another one of the many cpap related things that come with that YMMV sticker.

About the best you can do to battle the aerophagia is max out your exhale relief...or maybe use a cervical collar to keep the airway more open and need less pressure but then it comes with its own baggage. I am not so sure I would want to wear a cervical collar and especially not with a full face mask. Talk about annoying.
If it were me I would just stick with the nasal mask and not worry about a little mouth breathing leaking because I figure that would be less of a problem to deal with than the problems a FFM or cervical collar would cause me.

[zonker]

As for the aerophagia thing....some people find it fades away with time and others find they have it forever.....just another one of the many cpap related things that come with that YMMV sticker.

i'm in the second camp. while my aerophagia is drastically reduced, it still present as gas throughout the night.

in fact, last night, my system went nuts and i was back to the old days of tight belly! but taking off the mask, sitting upright and giving out a tremendous burp cleared that up.

[1speechpick]

As for the aerophagia thing....some people find it fades away with time and others find they have it forever.....just another one of the many cpap related things that come with that YMMV sticker.

i'm in the second camp. while my aerophagia is drastically reduced, it still present as gas throughout the night.

in fact, last night, my system went nuts and i was back to the old days of tight belly! but taking off the mask, sitting upright and giving out a tremendous burp cleared that up.

Thanks, Zonker and Pugsy, for your responses. I'm determined to find a solution. The aerophagia is causing nausea, reduced appetite, and increased GERD.

Is there a chance that a Bilevel machine would help decrease the aerophagia (even though I'm at lower pressures)?

[Pugsy]

Is there a chance that a Bilevel machine would help decrease the aerophagia (even though I'm at lower pressures)?

Yes, a chance ...no guarantees though.
We have forum member RobySue (not active for a while) who had bad (really bad) aerophagia issues even at extremely low pressures on the apap who went to a bilevel and obtained significant relief. She still had to use lower pressures and in an extremely tight range but her aerophagia was really bad if she didn't. She also had to compromise a bit and let a few apnea events slide because to try to kill them with higher pressures caused more problems than it fixed in terms of air in the belly issues.
I don't know if she talks about it much here at her blog but you might check it out or search her old posts here for the discussion.

http://adventures-in-hosehead-land.blog ... er_19.html

https://www.cpaptalk.com/search.php?aut ... 0&sr=posts

Her settings on the bilevel were like EPAP 4 with PS of 4 and max IPAP of 10 because her belly couldn't handle more.