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Agree about the dangers of unvented masks which are mostly designed for hospital use with a specific circuit and not with CPAP. Increasing dead space is certainly a way of increasing the carbon dioxide levels above the 'apnea threshold' but is difficult to control.

No mention yet in this post about simpler methods of controlling CO2. With Bilevel a reduction in the pressure support (Pressure support = IPAP minus EPAP) will help reduce the volume of ventilation, increase the CO2 levels and reduce the likelyhood of developing central periodic breathing. With CPAP a reduction in pressure may help reduce central events also probably by decreasing the volume of ventilation. Reducing the EPR (which is low level pressure support) can also reduce central events in some individuals (this is work in progress).

Personally I would try these methods before resorting to increasing dead space etc. In this case it might mean reverting to CPAP from Bilevel particularly if snoring is the only reason for being on Bilevel.
Ian

Hi All -

I am under the care of one of the physicians who wrote those papers about using dead space to improce CO2 control, etc. to improve control of central apneas.

Regarding the controversy around non-vended masks, the solution that my physician recommends, is to find a vented mask which you find comfortable, and then block the vents with putty or silicone to create your own comfortable non-vented mask. Then using the deadspace as prescribed with the appropriate vents in the hose (after the 10"). I've been on this therapy for years, and still living to tell about it.

Maybe this will help one of you guys... of course, better with the recommendation/support of a competent specialist.

This is the link to Respironics Whisper Swivel II Exhalation Port (part 332113) that must be used with any non-vented mask (including the mask that JDS74 put in trash):
https://www.cpap.com/productpage/whispe ... onics.html
Note that every time when a “non-vented mask” is mentioned in CPAP context, it actually means a non-vented mask AND this exhalation port.
Is it really dangerous to try a non-vented mask (with this exhalation port)? I do not know for sure, but I doubt.
From the whisper swivel description on its cpap.com page: “It is to be used only with Respironics Reusable Silicone Contour, Gold Seal and older Profile Lite masks that do not come with a swivel.” All these masks were quite popular many years ago and many people used them every night with their CPAPs. Yet I’m not aware of any epidemic “brain damages” or deaths among those patients (but I have to admit that I do not know much about CPAP history).

buran wrote:Note that every time when a “non-vented mask” is mentioned in CPAP context, it actually means a non-vented mask AND this exhalation port.

No it doesn't.

Online sellers sell the non-vented mask without a swivel/exhalation port. They don't even have any kind of warning on their web page. I presume the legit sellers only sell with prescription, but I don't know what they'd do if someone with a regular prescription for a CPAP mask placed an order. I've seen them for sale on places like eBay with no warnings.

Several people have brought home non-vented masks from the hospital or other treatment without getting the separate exhalation port.

Some hospital setups for respiratory devices use a different type of connection that may provide oxygen, measure flows, provide medicine, AND provide venting of waste air. Unvented masks are not always used with the Respironics Whisper Swivel Exhalation port, but there must be some form of venting.

I don't think an unvented mask WITH the exhalation port is dangerous. What's dangerous is accidentally assembling it wrong and using it without the expiration port. Maybe you'll forget it and assemble it wrongly after cleaning some day. If some user of normal masks gets an unvented mask and doesn't know they need to add a swivel vent, they'd be at risk.

I suspect a normal CPAP user would quickly realize something is wrong and take the mask off, although if they had a really leaky mask, they might not notice right away. If they were incapacitated and someone else is putting the mask on them, there could be trouble. If it's a "normal" CPAP user who's drunk or on medication, they might not figure it out in time.

archangle
Just to clarify: What is used in hospitals is “non-invasive ventilation”. A non-vented mask can be used with a ventilator without exhalation port. Note that ventilators also have CPAP/BIPAP mode. Here is the first link I found:
http://socmob.org/2013/11/socmob-using- ... e-lendrum/
But if we are talking about CPAP/BIPAP/ASV machine and EERS (as it was originally introduced in R. Thomas 2010 paper – Ref.[1] in Todzo post above), a non-vented mask is always meant to be used with exhalation port.
Yes, you can buy a non-vented mask with a regular CPAP prescription:
https://www.cpap.com/productpage/Respir ... -Mask.html
But if the mask is non-vented, the need of an “exhalation device” is usually (or may be always) written on the mask package.

-----eucapnic . . . roulette?
--at least DIY, without adequate training.

chunkyfrog wrote:-----eucapnic . . . roulette?

Eucapnic means at normal/optimal CO2 levels and so it is never ever dangerous to be eucapnic.

What is dangerous is to never ever treat the unstable breathing associated with sleep apnea whether through respiratory gain issues or the extra gain given to the respiratory system though the pressure imposed by the use of CPAP.

igdoc wrote:Agree about the dangers of unvented masks which are mostly designed for hospital use with a specific circuit and not with CPAP.

My guess it that the normal use of unvented masks is to efficiently plumb in an O2 feed. If you add O2 pre-vent you would be adding say 3 liters per minute oxygen to a circuit that will vent at 20 liters per minute or higher! You are not going to get a lot of O2 that way.

igdoc wrote: Increasing dead space is certainly a way of increasing the carbon dioxide levels above the 'apnea threshold' but is difficult to control.

Well it is a lot better than letting the breathing levels remain out of control!!! That would be unhealthy indeed!!

I find that it does make breathing levels much easier to control and much better sleep at night.

That said I only use it as necessary.

igdoc wrote:No mention yet in this post about simpler methods of controlling CO2.

Like it is somehow hard to wear a mask when you already have to wear a mask?

igdoc wrote: With Bilevel a reduction in the pressure support (Pressure support = IPAP minus EPAP) will help reduce the volume of ventilation, increase the CO2 levels and reduce the likelyhood of developing central periodic breathing. With CPAP a reduction in pressure may help reduce central events also probably by decreasing the volume of ventilation. Reducing the EPR (which is low level pressure support) can also reduce central events in some individuals (this is work in progress).

My musician brother is trying to make Bilevel work. He uses two fans blowing air and making noise in his room to help mask the noise of the “tone changes” he is very aware of as the fan speed changes to facilitate the changes in pressure each breath. Pitch is very important to a musician.

It has not been a “simple” change for him.

igdoc wrote:Personally I would try these methods before resorting to increasing dead space etc. In this case it might mean reverting to CPAP from Bilevel particularly if snoring is the only reason for being on Bilevel.
Ian

One of the reasons I have grown to appreciate the use of enhanced expiratory rebreathing space (EERS)[1] is that it is simple and simply reduces the unstable breathing with it's excessive arousals without causing arousals itself.

The end result is much better sleep and health.


[1]: Gilmartin G, McGeehan B, Vigneault K, Daly RW, Manento M, Weiss JW, Thomas RJ.
Treatment of positive airway pressure treatment-associated respiratory instability with enhanced expiratory rebreathing space (EERS).
Source: J Clin Sleep Med. 2010 Dec 15;6(6):529-38. Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Link: http://www.ncbi.nlm.nih.gov/pubmed/21206741

bacinmass wrote:Hi All -

I am under the care of one of the physicians who wrote those papers about using dead space to improce CO2 control, etc. to improve control of central apneas.

I was extremely fortunate to find that paper. I was dealing with great stress at that time and it greatly affected how CPAP worked for me. Excessive arousals (and even awakenings with my heart beating out of my chest and breathing hard wanting more air) along with dry mouth (and I am not a mouth breather) and Aerophagia became part of my then shredded nights.

Adding a bit of EERS[1] quieted things well!!!

bacinmass wrote:Regarding the controversy around non-vended masks, the solution that my physician recommends, is to find a vented mask which you find comfortable, and then block the vents with putty or silicone to create your own comfortable non-vented mask. Then using the deadspace as prescribed with the appropriate vents in the hose (after the 10"). I've been on this therapy for years, and still living to tell about it.

Maybe this will help one of you guys... of course, better with the recommendation/support of a competent specialist.

I really would like to see a kind of tapered aspect added to the simple formula you mention above. I think that if you studied the air flow waveforms you might well be able to design a system with several vents along the line. If the person was breathing at reasonable rates no air would be rebreathed (and so minimum amounts of air would be needed) but if breathing increased to dangerous levels the needed CO2 would become part of the scene.

I am glad to see EERS mentioned much more in the literature year to year. And indeed as they look more carefully at how effective the current therapies are not it is clear that something like EERS is needed for many.

But the ventilatory control aspect of sleep apnea is off the radar for many doctors.

Please do talk with your doctors about [1,2].

[1]: Gilmartin G, McGeehan B, Vigneault K, Daly RW, Manento M, Weiss JW, Thomas RJ.
Treatment of positive airway pressure treatment-associated respiratory instability with enhanced expiratory rebreathing space (EERS).
Source: J Clin Sleep Med. 2010 Dec 15;6(6):529-38. Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.
Link: http://www.ncbi.nlm.nih.gov/pubmed/21206741

[2]: Dynamic CO2 therapy in periodic breathing: a modeling study to determine optimal timing and dosage regimes
Yoseph Mebrate, Keith Willson, Charlotte H. Manisty, Resham Baruah, Jamil Mayet, Alun D. Hughes, Kim H. Parker and Darrel P. Francis
J Appl Physiol 107:696-706, 2009. First published 23 July 2009; doi: 10.1152/japplphysiol.90308.2008
Link: http://www.ncbi.nlm.nih.gov/pubmed/19628721