Help wanted on interpreting air flow shape

[PeterFD]

WisNaeMe said, ""Spiky" looks like expiratory mouth breathing".

I have recently come to suspect that this is the case.

I verified that, despite the ResMed chin strap being reasonably tight, by lowering my tongue and relaxing my lips I could get a smooth air leak without vibration (necessary for the observed smooth plateau during exhale).

I have now tried the Knightsbridge chin strap. What a nightmare! I put the chin strap on first and then the mask. Is that the wrong order? 

For some reason I could not avoid leaks, particularly near my eyes (I suffer from dry eyes). My mask and the KB chin strap jostle for supremacy in the same place at the back of my neck. I woke up during the night with pain in the jaw area and had to loosen the non-elastic strap. (The straps have no preset hooks, so each night would be a guess how tight to fasten each strap.)

The straps under my chin are too wide for my short jaw and so cut into my throat, particularly with my head down (if I were standing).

While lying on my back and clenching my teeth (not really necessary), if I lowered my tongue, air escaped through my lips. Therefore, the KB device is not really any improvement over the ResMed in this regard.

Maybe all I need is a good well-sealed mouth plus nose mask.

[WisNaeMe]

When I started with the KB chinstrap, I experienced similar problems to you and it took a few nights to get the position and tension on the straps right for me. I always put the mask headgear on top of the KB - though still struggled a bit initially with their respective velcro fastenings sticking to each other (and the pillow!). I also initially put the straps too far back towards my throat which cut in causing some discomfort.

So probably don't over tension the elasticated strap and use the 'non-stretchy' strap to regulate the force being applied. Only use the 'stretchy' strap to provide some flex and the 'non-stretchy' to keep things in position/place. But I found it's more about simply holding the jaw in place, rather than clamping it ...and that it wasn't necessary to overlay the straps - that they could be applied at slightly different angles to get a better hold/fit.

It maybe that the more parallel strap arrangement/bridge on your Eson just conflicts with the KB chinstrap, particularly at the back of the neck. I was using a ResMed P40 mask which has a lower profile and more criss-cross 'X' strap arrangement, so stayed well clear of the KB's back-of-the-neck velcro adjustment.

I actually bought two KB's of differing sizes - the first being too big (but with allowed me to put the mask straps below the KB) and the second one being the next size down, which was more skin-tight and which was the one I finally settled on using.

When it works it's great, but I found it requires a fair bit of persistence. I would stick with it a bit longer - it took me a good few days to master it.

[PeterFD]

Thanks for your experience, and perhaps I could learn to love it too, but the overriding consideration is, "Can it help me when the ResMed doesn't?"

If my jaws are clamped shut by me and I can still get air leaks from my lips, how can the KB help in stopping air leaks? The direction of the force is not important provided that it shuts my jaws, and the ResMed does that if it is tight enough. 

Agreed, the ResMed strap may retract my lower jaw a bit but by only a very small amount. My teeth are well worn down with irregularities which prevent my lower jaw being retracted very much when my jaws are fully closed.

Note that since my lower front teeth locate behind my upper front teeth, as is normally the case, my worn-down teeth force my lower jaw to be retracted more than when I was young. I have sometimes wondered whether I would benefit from a mandible advancement device which is sometimes used instead of (or as well as?) a CPAP machine.

[LaurenceShaw]

For many people, just having the jaw raised is sufficient to prevent mouth leaks, but of course one's lips might still open even with the jaw raised.  Mouth tape is more intrusive, but that might be the solution for you.  Or a full face mask. (You also ask about a mandibular advancement device ... I haven't heard of people using them to prevent leaks, but would be interested to hear from the community if that is a "thing.")

Although the Knightsbridge might not be the solution for you, I would note:
  (1) People wear the Knightsbridge both under and over the mask.  With the Eson mask, it may be that wearing the Knightsbridge over the mask would be preferable.  I can see that the rear strap of the Eson might press against the Velcro size-adjustment strap and that would be uncomfortable.
  (2) WisNaeMe's advice is correct regarding the tensioning of the straps.  You want the non-elastic blue strap to be snug and only add a gentle additional force with the elastic strap.  The Knightsbridge will maintain the jaw in the elevated position when the jaw muscles are relaxed.  It is not intended to prevent the jaw from opening when your muscles attempt to do so.
  (3) The Knightsbridge is purposefully designed to allow flexibility in where the straps are attached, so it should be possible to attach the straps so that they don't press into the throat.  If you have limited below-the-jaw area, it is okay for the front edges of the straps to extend somewhat forward from the tip of the chin.

As I note above, I'm not sure the Knightsbridge is the solution for you, but if you want to explore this further I suggest you contact me by phone.  Often, with front and view side pictures so I can see your head shape and how it fits, we can get it working.  The phone number is post on our website, Supplier #37.  (Please use that link -- keyword searches will still likely lead you to our counterfeiter.)

[tarah]

Here is a shot inspiratory nasal breathing, expiratory mouth breathing (on the right) The machine DOES NOT record a leak.

I recorded multiple instances of this while awake and sometimes it's not even obvious it's expiratory mouth breathing. It's just an "arousal" looking event.