Mouth Breathing (mouth leaks) with Nasal Mask- Waveforms

[Jay Aitchsee]

Flow wave examples of mouth breathing wearing a nasal mask:
23:43:30 to 23:44:00 Normal Breathing; Nose In, Nose out.
23:44:00 to 23:44:44 Total Mouth Breathing; Mouth in, Mouth out. 44 second apnea scored at resumption of nasal breathing, no leaks scored.
23:44:50 to 23:45:20 Exhalation by Mouth: Nose in, mouth out, scoring a leak of about 8L/min

Note: With a nasal mask, Flow is only that which passes through the hose connected to the nose. The machine can not directly measure any flow through the mouth. The machine determines leak by measuring the outflow compared to the inflow. If outflow is greater than inflow, ignoring mask vent rate, there is a leak. When exhaling through the mouth, some outflow is lost (to the hose) and the machine scores a leak. When inhaling through the mouth, inflow from the machine is reduced or stopped and the machine registers an apnea.
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Below:
Normal sleep breathing on top, expiratory mouth breathing on the bottom in large leak (shaded area)
Notice the flattening of the expiratory portion of the wave with exhalation by mouth.





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Knowing whether leaks are from the mouth or mask could be helpful. The sample below contains two sets of flow waves from the same night taken during periods of over threshold high leak as indicated by the shade. The expiratory portion of the top set has the rapid rise and relatively flat run typical of a mouth leak. The bottom sample does not.
Since the over threshold leak is present with or without mouth leaks, I can assume it to be a mask leak and my pillows or headgear need attention.


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Classic mouth leak plateau shaped waveforms



Mouth Leaks Defined: Patent Application

In some cases, pressurized air flows through the velopharyngeal sphincter (i.e. between the lateral pharyngeal walls and the soft palate) into the oral cavity and then out through the lips, resulting in a mouth leak. When a mouth leak occurs, pressurized air does not reach the lungs and does not contribute to ventilation, thereby rendering the treatment less effective or ineffective. In addition, because of the one-way airflow through the nasal passages, mouth leaks tend to dry the mucosal surfaces resulting in nasal congestion after only several hours of use. In some applications, the CPAP system will apply a higher pressure through the nose mask when a mouth or mask leak is detected to compensate for the leak which only exacerbates the problem. In many cases, the side effects are often so severe that the patient is no longer able to tolerate treatment.

For more on this subject, please see viewtopic/t171982/Mystery-solved-ever-h ... l#p1255757 by member yrnkrn

[palerider]

nice!

[Holden4th]

So if I look at an OA, and then works backwards on the flow rate graph, I can see where I am mouth breathing?

[Jay Aitchsee]

So if I look at an OA, and then works backwards on the flow rate graph, I can see where I am mouth breathing?

Maybe, but probably not. Better might be to examine the area where some leak is occurring.

If you are inhaling through your nose, but have leaks from your mouth, your flow wave will look similar to that of example in the shaded area above. The expiratory portion of the flow wave (the negative part below the "0" line) will become flatter and a leak will be shown. This is because, with a nasal mask, the machine is measuring the flow only through your nose. It senses the amount inhaled, but since part of the exhaled amount is lost through the mouth, it doesn't sense that and the expiratory flow measured is less, with the difference being shown as a leak. The more of the expiratory flow lost through the mouth, the flatter the trace and the greater the leak.

If you are exhaling through your mouth, then you might also be inhaling through your mouth. But here it becomes trickier to determine. With a nasal mask, a breath taken totally through the mouth will look like a short term apnea. The machine senses no flow through the nose and the top of the flow wave is chopped off. If you were to continue to inhale totally through the mouth for several breaths (a breath typically lasts 4 or 5 seconds) exceeding 10 seconds, an apnea would be scored. But, as far as I can determine, it would appear just as any other apnea. So, you might suspect an OA to be a result of a mouth inhalation, if mouth exhalation was shown nearby as described above, but not be sure. Further complicating the determination of mouth inhalation is that I've found that sometimes the machine will score a CA rather than an OA. In a lab this would all be sorted out by having additional sensors.

In prolonged mouth breathing sometimes the flow wave looks flat, but if examined closely there could be small positive flows at the start of each breath representing a small amount of inflow through the nose. If this flow is large enough, the machine recognizes it as a breath and no apnea is scored. Examining the breaths immediately preceding and following an apnea might yield additional clues. Large breaths before might indicate a disturbance, while large breaths after might indicate a true apnea had occurred. See examples here.

[ChicagoGranny]

[PEF]

Hi Jay - I am very interested in this. I don't quite understand how to examine these waves using Sleepyhead, how to zoom in - Do I do this in Sleepyhead or in Imgur? I want to look at these in my own case.

After doing so well for so long, I am having problems again that are causing me to not use my CPAP much now for fear of my nose getting severely stuffed in the night. The weather here has changed to the tropical wet season and, since we now have gone from El Nino effects to La Nina (colder and wetter), I seem to be having serious allergy issues. I suspect the 100% humidity in the middle of the night is causing me extreme nasal congestion. To prevent mouth breathing, I use a nasal mask with tape over my mouth which worked fine before. However, the last week or so, I wake up in the middle of the night gasping for air because my nose is stuffed up and running, so I take off the mask and the tape. I have a FFM, but still cannot even get to sleep with it, if I am lucky enough to even get it on successfully. Tonight, I am going to disconnect the humidifier on my machine in case that is making things worse. Before, I was using the air conditioning, but now I am not. The air conditioning tended to reduce the humidity in the room.

So I want to try to get a better idea of what is happening at night. My impressions about what goes on while I am asleep have been wrong in the past. So could you explain how to zoom in to the waves?

[Jay Aitchsee]

So could you explain how to zoom in to the waves?

Sure, there are several ways. I'll cover a few.

1st, Select the Daily View in SleepyHead. The Flow Rate Chart should be among the charts on the right side. If it isn't, look to the right side bottom and check the push button "Graphs" to make sure the Flow Rate is on (green). If it's not listed, go to File/Preferences/Waveforms and put a check in the box.

Once the Flow Rate waveform is displayed, go to "View" (top left) and check "Toggle Line Cursor" to get the green cursor to show on your charts.

Place the cursor over a time you want to examine more closely and left click until you have reached the desired level of magnification. You can click down to one minute fills the screen. If you want to go even larger, left click and drag to expand an area further.

Once on the chart side, you can: Left click and drag to expand an area, Right click and drag to move the area in time, Left click to zoom in, Right click to zoom out.

You can use the up down left right arrows to do the same functions, i.e., zoom in, out, move left, right.

You can open the events tab on the left and left click on an event which will zoom to the size specified in the box at the bottom. You can click on an event in the Event Flags Graph and it will zoom to the size selected under the Events Tab on the left.

You can reset all graphs to 100% by right clicking on any graph label area and selecting 100% zoom level.

And probably a few more.

[PEF]

Thanks so much, Jay. Tonight I am going to use my nasal mask without using tape. Then examine my data tomorrow. I hope to see exactly how much trouble I am having with mouth breathing.

I continue to work at stopping the mouth breathing entirely. I practice during the day holding my tongue against the roof of my mouth and then opening my mouth that way and even talk like that. I am trying to get out of the habit of letting my tongue drop down. So far I have made progress, but not as much as I would like.

[Jay Aitchsee]

If your nasal mask is relatively leak free, then a comparison of nights with and without tape should indicate how much mouth leaking is contributing to the total. Unfortunately, the "best" solution to mouth leaks is probably a full face mask because it allows either nasal or oral breathing without compromising therapy. Unfortunately as well, I also know from experience that not all of us can tolerate a full face mask. The next best solution is probably tape, but that can also become intolerable. I am working on a solution I think is slightly better than tape. Stay tuned.

[Sylvia54]

Thanks so much, Jay. Tonight I am going to use my nasal mask without using tape. Then examine my data tomorrow. I hope to see exactly how much trouble I am having with mouth breathing.

I continue to work at stopping the mouth breathing entirely. I practice during the day holding my tongue against the roof of my mouth and then opening my mouth that way and even talk like that. I am trying to get out of the habit of letting my tongue drop down. So far I have made progress, but not as much as I would like.

Hi PEF; This includes another tip that helps control the mouth breathing/leaking, think its helped me (most of the time) but as you know, not an immediate fix;

Tongue Position
Learn to keep your tongue pressed to the roof of the mouth. This method helps to prevent mouth leaks by stopping the air getting out, thus no more CPAP dry mouth.
Make an effort before falling asleep to seal your lips and create a small suction inside your mouth and push your tongue forward against your teeth and up to the roof of your mouth. The suction should hold your tongue there.
Practice (during the day) keeping your tongue positioned in the roof of the mouth.

Have you tried a chin strap? I wear the "Halo" chinstrap, mfr Breathewear, Inc. Ordered it from cpap.com. It's wider, more comfortable, easy to adjust, and supports the chin better than most. Again, not an immediate or complete fix but helps me. Didn't take long to get used to the feel.

[Jay Aitchsee]

Here's an item I suggest rather than tape. It's a stretch headband made from a thin, soft cotton like material similar to that of a T shirt. It is double thickness (a tube), but still thin with a seam at one edge. It doesn't unravel when cut. It is about 2.5 inches wide and fits nicely between the nose and chin. I think it would fit most without being too tight or loose. I wear it just like a headband only pulled down over the mouth and ears. I cut holes for my ears. It does not interfere with a P10 or Dreamwear nasal mask. When it is worn with the seam down, it tends to keep the bottom lip closed. It is porous so that chipmunk cheeks are less likely to form, but at the same time, it restricts the flow and reduces mouth leaks considerably. It also softens the noise of mouth leaks and discourages mouth inhalation. I've worn it for about two months and it has reduced my average nasal mask leaks (mouth) from an average of about 12L/m to about 5 rarely exceeding the large leak mark. I've see them sold at various places including grocery and drug stores. They cost about $5 for a set of five and are washable. One set should easily last a year. Here's some at Amazon.

P.S. I put the head band on and marked it with a pen to determine where to cut the ear holes.
Like this:

[sleepychar]

I am going to try the Scunci suggestion... I am a CPAP newbie. Just completed my third night sleeping with the machine. Auto setting from 4-16. So far things are going way more smoothly than I anticipated. After a horrible experience with the first DME Supplier I went to, I found a company that seems to be very responsive and caring. I will be seeing the nurse practitioner in my sleep doctor's office in about two weeks to assess how things are going. The one issue I seem to be having is that I woke up night before last and became aware that I have been exhaling through my mouth instead of through my nose. I think this happens more when the pressure goes up, which is probably logical for that to happen but probably the time I would most benefit from not exhaling from my mouth. The CPAP machine shows there was a 12L leak last night which I suspected was related to the mouth exhalations but this thread seems to confirm that possibility. I think it was 14L the night before. There is a good seal for the mask and I haven't felt uncomfortable breathing. I am trying to be aware of exhaling from my mouth but when I am asleep, of course... I was thinking of ordering a chin strap to try as I really like the nasal pillow mask and I would like to not have to go to a larger type mask unless I absolutely have to. So thank you for posting this suggestion. I am going to try it and I will post how it works out.
So far I have been looking only at the machine display read-out and the ResMed MyAir reports. Eventually I want to learn how to use SleepyHead but I haven't wanted to overwhelm myself with too much information at this point. I want to thank everyone who posts to this site. I have learned so much already just from reading what everyone else has said about their issues and the suggestions people make to resolve them.

[PEF]

Ok - something really interesting that shows how what I often perceive as happening in my sleep is NOT what really happened.

Last night, I forgot to disconnect my humidifier (which I intend to do tonight) until right before I went to bed and realized I needed to change out the hose, so put it off. So the humidifier was still working.

I was so tired that I decided to get a good night's sleep by going to bed the way I was most comfortable - using my P10 and mouth tape. I sleep best this way UNLESS my insomnia is bad. Knowing how bad my allergies can get at night, I took a Clartin to hopefully prevent a stuffed up nose from waking me up. But last night I got to sleep almost right away. 2 hours later (I know that from Sleepyhead this morning, but did not know what time it was when I awoke), I woke up aware that my mouth was extremely dry. I vaguely remember trying to wet my mouth by moving my tongue around and then going back to sleep, which usually works, but this night it did not work and I began to choke and cough. I pulled the mask and mouth tape off. My nose was a little stuffed up, but not bad enough to abandon the mask. I THOUGHT that the dry mouth was because of large mouth leaks, so I did not put the mask back on and went back to sleep without it. I slept pretty well, but awoke with a dull headache and lots of nasal congestion and phlegm, which always happens when I don't wear my mask.

I EXPECTED to find massive large leaks when I imported my data this morning, but was I ever in for a surprise. I was looking a almost perfect data for those 2 hours I slept with the mask. NO large leaks at all and the leak numbers weren't bad for me - very short periods of leaks of 13L to 21L. So obviously, I could have reapplied the tape and put the mask back on and had a very good night's sleep. I chose not to in the middle of the night because of my fear of my nose getting stuffed up and choking because of that. This just goes to show how often what I perceive happening while I sleep is not what is really happening. I am glad to have Sleepyhead to show me that.

This is not the first time I have shot myself in the foot by using antihistamines. So many doctors tell me to take them when using CPAP in allergy season. The first night or 2 they work fine. Then they start to make my mouth and throat so dry that I often choke in the middle of the night, which is probably what caused my extreme dry mouth last night, NOT excessive mouth breathing. the other thing that happens to me when using antihistamines is a very unpleasant rebound effect when I stop using them.

Jay - I have done comparisons of nights using tape and not using it. My masks are relatively leak free unless my nose gets stuffed up. So when I don't have nasal congestion, the only difference is that, nights I use tape, I do not see any large leaks at all and when I don't use tape, I see some large leaks. However, the actual large leak time tends to be no more than 20 to 30 minutes out of 7 or 8 hours.

Thanks so much for your "head band" suggestion. I am going to order one and try it. I have tried both cervical collars and headbands without much success. I usually can't get to sleep at all with a cervical collar and the headbands hurt my jaw.

Sylvia - Thanks for your suggestion about tongue position. I keep practicing.

For some reason, I can't get a lot of the Sleepyhead functions to work. I don't know if it is my computer or the software. I was not able to get the cursor when I selected "View and toggle cursor". Nothing happened. I also was not able to get the 100% zoom to work - nothing happened. My husband, who is better with computers than I was not able to make it work either.

[PEF]

There is a mistake in my last post. What I meant to say is that I have tried CHINSTRAPS with no luck. I did not mean headbands.

[ChicagoGranny]

Knowing how bad my allergies can get at night, I took a Clartin to hopefully prevent a stuffed up nose from waking me up.

Antihistamines can be helpful for short-term problems. But, for chronic problems, an allergist should be consulted - http://acaai.org/locate-an-allergist/results?zip=panama