M-Series Leaks showing up as Apena's?

[Rustyolddude]

Was having some minor leak issues , little intermittent leaks at the corners of my mouth and nose. Leak line was starting to look a little choppy, up 3-5 points, no big leaks. The Apneas were creeping up in number too. As I looked at the charts, the leak spikes also seemed to directly corelate to apnea events atrificially inflating my AHI. Once I readjusted things and got my leaks back under control, the AHI came down. I'm certain the leaks were so small they had no effect on my therapy, they were spikes, not broad periods of leakage. Anyone else notice something similar?

[turbosnore]

Seeing the curves might help.

Anyway, I think it is possible that leaks and higher AHI may be coupled via REM:
Vivid REM -> higher AHI AND more movements -> leaks.

[ozij]

There's no movement in REM sleep - all voluntatry muscles are paralyzed.

AHI leak correlation can be:
Something in the machines logic
or
Leak causing arousal --> non-breathing caused by arousal / tossing and turning and that type of non-obstructive apnea will get registrered.

Restless, sleepless nights -- the kind of sleeplessness caused by thoughts -- often have the machine registering more apneas and hypopneas for me.

O.

[turbosnore]

Aha, always learning something new.
I have been under the wrong impression that dreams and movements go together in REM whereas
phenomenon like sleepwalking doe take place typically in deep sleep stages.

Anyway, found this in http://www.sleepeducation.com:

Sleepwalking can occur when sleep is fragmented by other sleeping problems. Obstructive sleep apnea (OSA) is a common
medical problem that can lead to frequent arousals from sleep. This may increase the risk of parasomnias such as sleepwalking.
Symptoms of OSA include snoring, waking up gasping for air, and daytime sleepiness. Treatment of OSA may improve sleepwalking.

Maybe some bodily restlessness is connected to apneas in the deep sleep.

[GumbyCT]

Either,
Leaks will cause a drop in treatment pressure and allow apneas to occur.
Or when apneas occur the leaks arise because (the flow is blocked and) the mask does not fit correctly.
Hard to tell which came 1st.

This is exactly why it is said - you MUST get your leaks under control BEFORE your AHI can be believed. Your treatment air will take the path of least resistance.

HTH

[Velbor]

.... Leaks will cause a drop in treatment pressure and allow apneas to occur. ....

Many knowledgable, experienced and thoughtful xPAP users, such as I know GumbyCT to be, express this view.

Others of us (if I may be so bold as to classify myself similarly) would prefer a more nuanced statement:

VERY LARGE AND PROLONGED leaks MAY OVERWHELM THE MACHINE'S ABILITY TO COMPENSATE AND cause a drop in treatment pressure WHICH MAY allow apneas to occur.

Leaks of any kind, amount and duration may have a variety of unwelcome effects on the xPAP user. But the machinery we use (all major brands) is well enough engineered that it takes a MAJOR leak insult to compromise machine function and reporting.

Regards, Velbor

[DoriC]

On our reports there doesn't seem to be any correlation between leaks and apneas. Data can show an almost straight leak line and there can be some corresponding apneas but reports showing a choppy leak line show no corresponding events. There doesn't seem to be any correlation between snores and apneas either. So will this question ever be answered??

[ozij]

The "low leak" /apnea relationship is not necessarily machine related, it may be so for some people, and much less so for others.

A case in point is BleepingBeauty, whose data showed a tremendous difference between leaky and non-leaky nights, and who only got her therapy going only when show found the mask that would keep her from leaking -- even a bit.

Good night
img]http://i675.photobucket.com/albums/vv12 ... 1245343281[/img]

Bad night


Here's Muffy's explanation of why leaks may have disrupted BB's breathing.

viewtopic.php?p=390738#p390738

While the Respironics software looks at leaks in a very coarse fashion (compliments of the "25/32 Rule") I think the pattern of leaks in BB's case shows that her event salvos are always associated with an unstable leak pattern, and that event-free breathing is always associated when Observed Leak approximates Designed Leak.

Finally, I believe what makes BB so susceptible to this phenomenon is her low CO2 reserve. This consideration will be better seen in looking at FRC in complete PFT. Her physical stature should make her at risk for a low value here.

Muffy (aka "Still Another Guest") runs a sleep center, and knows whereof he speaks.

[LinkC]

VERY LARGE AND PROLONGED leaks MAY OVERWHELM THE MACHINE'S ABILITY TO COMPENSATE AND cause a drop in treatment pressure WHICH MAY allow apneas to occur.

That's been my understanding, as well. Either I read or assumed that when Respironics reports "Large leaks", that is their criteria for what is deemed "Large"...i.e. "large" is too much for the machine to compensate.

[GumbyCT]

Just fixin Ozij's link -

Good night


Bad night


Here's Muffy's explanation of why leaks may have disrupted BB's breathing.

viewtopic.php?p=390738#p390738

While the Respironics software looks at leaks in a very coarse fashion (compliments of the "25/32 Rule") I think the pattern of leaks in BB's case shows that her event salvos are always associated with an unstable leak pattern, and that event-free breathing is always associated when Observed Leak approximates Designed Leak.

Finally, I believe what makes BB so susceptible to this phenomenon is her low CO2 reserve. This consideration will be better seen in looking at FRC in complete PFT. Her physical stature should make her at risk for a low value here.

Muffy (aka "Still Another Guest") runs a sleep center, and knows whereof he speaks.

Don't forget about the fact that an apnea can lead to a leak also. And if you dip below the threshold pressure that will keep your airway open - I would guess you are setting yourself up for more events whether hypops or apneas.

[Scarlet834]

From personal experience and some conversation with my RT I agree that "excessively large and prolonged leaks can compromise therapy". The REMStar Pro is supposedly able to compensate for smaller leaks. There is a definite difference in how I feel (for me) between when my mouth has been hanging open vs. the mask slipping slightly vs. slight puffs of air escaping the mouth. I have a meeting in about a week and a half where we're going to go over all my data in detail and hopefully I will understand much more after that.

I would be interested in clarification of the statement that the AHI cannot be believed until leaks are under control. I can imagine that in extreme cases, the large leaks, so much air is escaping that the machine cannot adequately register how our own breathing impacts pressure in the hose. However, if leaks are in the range where the machine can presumably try to compensate, can't it also register breathing changes? I think it can register events properly, based on my own experiences and how the AHI correlates with how I feel. I have no reason to doubt the numbers, although I will admit 1 or 2 exceptions where I've gone, "What the #*(^(#%?"

The one thing that I've theorized re: AHI numbers is that if you have a night where you really don't sleep well, presumably for non-apnea reasons, you could possibly have a low AHI just because you never reached deep enough sleep to trigger apneas. My insomniac nights are thankfully very rare. I also once recorded a particularly dense cluster of OAs where I know for a fact I was awake, probably thrashing around. I found it interesting.

[ozij]

Thank you, Gumby.

From my personal experience, there is a major difference between mask leak, and mouth leaks. Mask leaks can easily become large leaks and overwhelm the machine's ability to compensate. Mouth leaks on the other hand (at least mine) never overwhelm the machine's ability to compensate, but they do invalidate the therapy.

O.

[Velbor]

.... Mask leaks can easily become large leaks and overwhelm the machine's ability to compensate. Mouth leaks on the other hand (at least mine) never overwhelm the machine's ability to compensate, but they do invalidate the therapy.

Thank you, ozij. We've discussed this before, and our ongoing difference in understanding continues.
In what way do you believe that mouth leaks "invalidate the therapy"?
If they do not "overwhelm the machine's ability to compensate", what do you believe is happening?

I maintain that in the xPAP environment, even with (moderate) mouth leak, the pressure in the mouth is still the same as the pressure in the throat is the same as the pressure in the nose is the same as the pressure in the mask is the same as the pressure the machine is delivering and maintaining. I maintain that in a "limited" volume as is involved in xPAP therapy, the location of a leak, so long as it can be compensated for, does not matter. Just because the mouth may be physically "closer" to the site of airway obstruction than is the mask cushion, there is no difference in the effect of leak on pressure anywhere in the system. This is my understanding of the physics involved.

I look forward to your thoughts. Blessings, Velbor

[ozij]

.... Mask leaks can easily become large leaks and overwhelm the machine's ability to compensate. Mouth leaks on the other hand (at least mine) never overwhelm the machine's ability to compensate, but they do invalidate the therapy.

Thank you, ozij. We've discussed this before, and our ongoing difference in understanding continues.
In what way do you believe that mouth leaks "invalidate the therapy"?
If they do not "overwhelm the machine's ability to compensate", what do you believe is happening?

This is my understanding, Velbor:

The aim of the pressurized air supplied by the machine is to keep your tissues from sagging and closing off your airway.
The pressurize environment created in the"mouth /nasal cavity/upper airway" is supposed to keep the soft tissues from collapsing. As long as that system is closed, pressurized air, supplied by the mask and entering through your nose will push against the soft tissues. When they start sagging and or collapsing, the resistance of the pressurize air pushing against them will keep them from collapsing (most of the time).

With the mouth open, when the tissues start sagging, there will be no resistance to the sag, the pressurize air streaming into your nasal cavity is simply rerouted, and escapes through you mouth into the open room. Your collapsing tissues push, and the air column that was supposed to maintain them open obligingly moves out of their way.

The main issue in this therapy is not the amount of pressure supplied by the machine, and whether a leak is compensated for, or not. The issue is having a patent airway. When your mouth is closed, and your tongue sealed against the palate, the path of least resistance is in the soft tissues, and the pressurize air pushes against them and will keep those tissues from sagging.

When your mouth is open, the path of least resistance for the pressurized air is out of your mouth, and that is the path it will take, while your tissues will sag happily down closing off your airway. Pressure is still maintained within the machine's ability to compensate, but not your patent airway or your breathing.

The machine can't compensate for the air being rerouted into the room.
O.

[Velbor]

The aim of the pressurized air supplied by the machine is to keep your tissues from sagging and closing off your airway.
The pressurize environment created in the"mouth /nasal cavity/upper airway" is supposed to keep the soft tissues from collapsing. As long as that system is closed, pressurized air, supplied by the mask and entering through your nose will push against the soft tissues. When they start sagging and or collapsing, the resistance of the pressurize air pushing against them will keep them from collapsing (most of the time).

Here we are almost in agreement. The sticking point is that your view requires that "the system be closed." In fact, "the system" is NEVER closed. It is open by design in the venting of the mask. It is often open unintentionally through seal leak. You may be suggesting that these leaks are "external" to the mouth-nasal-upper airway. I reply that this "externality" is irrelevant - in terms of pressure, the hose and mask and airway are all the SAME system. We also have the issue of your requiring a "closed" airway system, whereas I see the need only for an adequately closed system, one in which the machine is able to provide pressure compensation for the leak flow losses.

With the mouth open, when the tissues start sagging, there will be no resistance to the sag, the pressurize air streaming into your nasal cavity is simply rerouted, and escapes through you mouth into the open room. Your collapsing tissues push, and the air column that was supposed to maintain them open obligingly moves out of their way.

You seem to present an "all-or-nothing" scenario. If the mouth is gaping open, I agree, the leak would be of such an extent that the machine will be unable to compensate. But "mouth leak" may often be far smaller, well within the ability of the machine to maintain pressure. It is not air flow from the machine which holds the airway open, it is air pressurewhich is produced by the flow, when the flow encounters manageable leak. Quantification of the amount of mouth leak is essential; the simple presence of "some" mouth leak does not necessarily impair therapy.

The main issue in this therapy is not the amount of pressure supplied by the machine, and whether a leak is compensated for, or not. The issue is having a patent airway. When your mouth is closed, and your tongue sealed against the palate, the path of least resistance is in the soft tissues, and the pressurize air pushes against them and will keep those tissues from sagging.

When your mouth is open, the path of least resistance for the pressurized air is out of your mouth, and that is the path it will take, while your tissues will sag happily down closing off your airway. Pressure is still maintained within the machine's ability to compensate, but not your patent airway or your breathing.

The machine can't compensate for the air being rerouted into the room.

The "goal" of therapy is certainly, as you state, having a patent airway. The "means" of achieving this most certainly IS pressure and leak compensation - that's how CPAP works. "Least resistance" is not the same as "no resistance". In a mouth-wide-open situation, there is no resistance to flow, and no possibility of pressure compensation. In a small/periodic-lip-leak situation, there is resistance to flow, and if the machinery can compensate for the pressure loss due to that restricted and limited flow, adequate therapy is still providable. The machine OFTEN CAN compensate for SOME air being rerouted into the room, as it does for venting and small cushion leak - AND small mouth leak.

The location of the leak is not the issue; hose-mask-airway from an airflow hydrodynamic perspective is all the same system. The size of the leak is the issue. If the machine can compensate for flow loss AT ANY SITE within the CPAP system, and maintain pressure THROUGHOUT THE SYSTEM, then adequate therapy remains available.

Thank you, ozij, for engaging in this conversation. Blessings, Velbor