Sleepweaver masks

[symmit]

<puts fluid dynamics engineering head on> actually it is a dynamic not a static system as the fluid (air) is moving, therefore the static (measured) head declines the further you get away from the pressure source, so the pressure at the mask end of an 8' tube will be less than 6' one. As the viscosity of air is low, the flow is turbulent and the tube roughness is small, the difference will only be small though.

The pressure difference is why your set-up has the tube back from the mask (the air in there will be static, so no pressure loss), and the same for a fully titrated sleep study. Most systems are calibrated based on a standard 6' tube and mask leak rate, so the pressure delivered by an 8' tube will be slightly less. By my quick off-the-cuff calculations though it would be less than 0.2 cmH2O difference when a machine is running 16cm H2O

15 years since I last did Fluid Flow anaysis...never thought I'd be doing it again.

Thanks for the detail - of course with the system being vented it is a dynamic system, in fact the air in the mask is also moving and can be quite turbulent, but I wanted to keep the model simple - I'd forgotten the vent makes it constant flow...

10 ft tubes were another option - if anyone has a noisy flow generator it could be a cheap solution - put it in the next room

The constant adjustment of flow to maintain pressure is one of the reasons I prefer mine on a constant pressure setting and not in flex mode - the reduction in pressure on the exhale causes mask movement, which I find offputting, even though the stats seem to infer I get slightly better oxygenation through the night in flex I find it harder to get to sleep. Especially irritating with the sleepweaver.

[DebbieT]

Thanks for all your advice. my pressure is at 10 and i don't use a the ramp. I tried again last night but still couldn't get a seal, i even tried 3 different types of headgear to see if that helps but it didn't. I will have another go at the weekend when i may be more relaxed. The only way I can get a seal is if I hold it down over the bridge of my nose which obviously i cant sleep doing that all night.

I am not giving up yet

[Fredxx]

The CPAP machine blows air to a set pressure, since static pressure in a fluid (such as air) is pretty much constant throughout the fluid the pressure sensor in the machine that sets the flow rate doesn't care how long the tube is, only if it leaks...

<puts fluid dynamics engineering head on> actually it is a dynamic not a static system as the fluid (air) is moving, therefore the static (measured) head declines the further you get away from the pressure source, so the pressure at the mask end of an 8' tube will be less than 6' one. As the viscosity of air is low, the flow is turbulent and the tube roughness is small, the difference will only be small though.

The pressure difference is why your set-up has the tube back from the mask (the air in there will be static, so no pressure loss), and the same for a fully titrated sleep study. Most systems are calibrated based on a standard 6' tube and mask leak rate, so the pressure delivered by an 8' tube will be slightly less. By my quick off-the-cuff calculations though it would be less than 0.2 cmH2O difference when a machine is running 16cm H2O

15 years since I last did Fluid Flow anaysis...never thought I'd be doing it again.

[symmit]

Is there no pressure drop in using an 8 foot over a 6 foot hose?

The CPAP machine blows air to a set pressure, since static pressure in a fluid (such as air) is pretty much constant throughout the fluid the pressure sensor in the machine that sets the flow rate doesn't care how long the tube is, only if it leaks.

That's why you can hear the speed of the motor change even if the machine is fixed - it will increase the flow if there is more leakage to keep the same pressure, and increase the flow when you inhale and decrease it when you exhale. It's also why you get a huge gale if you take the mask off (or lose it in the night) as it is increasing the flow in order to bring the pressure back to the required level.

Additionally my machine has a seperate "pressure line" which measures the pressure at the mask rather than at the machine - I'm not really sure this has any real advantage but it's how it is.

[Barely Awake]

We're looking to source universal 90 degree elbow couplings with 360 degree swivels on both ends so you can make masks like these behave more like you want in terms of routing the hose.

I'm sure you know they exist already James, but I have a universal 90 degree elbow with a 360 degree swivel on one end. I don't use it but I can have a look to see if it has a manufacturing mark or name if you wish.

[Barely Awake]

I've just ordered an 8 ft hose specifically because of this, if my wife gets up early I tend to take up the whole bed, which has resulted in a disconnected mask twice now!

Is there no pressure drop in using an 8 foot over a 6 foot hose?

[symmit]

So indeed, for the time being, you will probably find that with the SleepWeaver, the hose will point downwards along your chest only. Whether or not it can then loop back up depends on your tubing, hose management arrangements and how you sleep.

I've just ordered an 8 ft hose specifically because of this, if my wife gets up early I tend to take up the whole bed, which has resulted in a disconnected mask twice now!

[James @ Intus]

but you say, "down only hose position" and that may mean it's not viable for me.

I take it this means you'd need a sizeable loop in the hose, from mask down toward your navel, before heading vertically upward to a HoseLift - kinda making the HoseLift a waste of time?

The SleepWeaver doesn't have the double 360 degree swivel that general masks have. It has a single-directional 360 degree swivel so indeed the hose points downwards, which may not be everybody's favourite direction.

We're looking to source universal 90 degree elbow couplings with 360 degree swivels on both ends so you can make masks like these behave more like you want in terms of routing the hose. But despite the myriad of couplers and adapters available to us, we've yet to find this exact piece (I personally would have thought to exist). I'll make this a suggestion to the manufacturers as well, they're very open to ideas for future developments.

So indeed, for the time being, you will probably find that with the SleepWeaver, the hose will point downwards along your chest only. Whether or not it can then loop back up depends on your tubing, hose management arrangements and how you sleep.

[James @ Intus]

if anyone has any suggestions i would be grateful

Hi Debbie,

Sorry to hear your first attempt didn't go so well.

We've had less than half a percent of people who fell outside of the one-size-fits-almost-all range. You'd have to be specifically petite to be amongst those.

So let's see if we can get there with the straps, perhaps have a try before you go to bed as well.

And which pressure is your machine at?

[Tigers Fan]

Down only hose position

Hi symmit

You may have just saved me a lot of dosh! Ive been ever more tempted to buy one by all the positive SleepWeaver reports but you say, "down only hose position" and that may mean it's not viable for me.

I take it this means you'd need a sizeable loop in the hose, from mask down toward your navel, before heading vertically upward to a HoseLift - kinda making the HoseLift a waste of time?

TF

[symmit]

Well yesterday after a few months of saving my sleepweaver mask arrived and with great excitement I went to bed to try and fit it. After an hour of lengthening and shortening the side and top straps i finally gave up totally disappointed. I have fairly small features and the hole on the mask seemed too big to be able to get a proper seal. I had leaks all over the place and especially into my eyes, will try again tonight but if anyone has any suggestions i would be grateful so it doesnt turn out to be a total waste of £100.

Debbie

Hi Debbie - let me try and help you from my experience with this mask so far.

Firstly as I have mentioned elsewhere, the mask is a bit of a comprimise, in exchange for a mask that doesn't irritate the face it's quite sensitive of positioning and can leak in unusual places.

This is what works for me.

Loosen the top strap. Make sure the neck strap is as low as you can get it behind your neck (if you can get the side straps below your ears) then tighten the side straps quite tightly.

Well before bedtime lie down and get set up.

Turn on your machine and cancel the ramp (so you're at full pressure) - they leak less as the pressure goes up (mine is silly at the ramp start of 4, if you can adjust it then go up a couple of notches on the ramp start pressure on the machine).

Find the tightness of the top strap that causes the lowest leakage into the eyes. Then pull the mask away from your face a little, remount it as low on your top lip and nose as you can (this brings the inner hole seal bit over as much of the nose as possible) and gently rest it back. Keep adjusting until you've got minimal leakage.

Personally I'm not bothered about the slight leakage, after all there is built in leakage and as long as the pressure is still at your therapy pressure then the effectiveness should not be affected - it's very minor. Also after a few nights I feel the material becomes more flexible and stretchy to your face. With adjustment you can get the leakage down or eliminated.

I find now it just slips on and off with the stretchiness of the headgear (it does need quite a lot more headgear tightness than my silicone mask) without having to undo the velcro, so it stays adjusted most nights, I will admit I don't wash it out every day (about every 2-3 days) although with the cold / flu I've just had I have been doing it daily. As per the instructions general washing in warm soapy water can be done with all the headgear in place.

You'll have to weigh the pros and cons for yourself, whether the fiddly fitting, down only hose positioning and poor performance at low pressures is worth the feeling you get from sleeping all night at higher pressures and waking with no face marks or discomfort. And if like me you like to sleep on your side I can't imagine any hard mask is nearly as comfortable for side sleeping. When you roll to your side a little wiggle may be needed again to get it sealed.

Hope the above helps - I'm sure ElleCee will have more advice too!

[ElleCee]

You could try a remzzz liner with it. I use them and it helps the seal but I have to fold over the bottom of the remzzz otherwise I would end up eating it I was also told that it leaks more at the higher pressure so am hoping that mine is better still on a setting of 10 rather than at 18.
All the best
Lorraine

[DebbieT]

Well yesterday after a few months of saving my sleepweaver mask arrived and with great excitement I went to bed to try and fit it. After an hour of lengthening and shortening the side and top straps i finally gave up totally disappointed. I have fairly small features and the hole on the mask seemed too big to be able to get a proper seal. I had leaks all over the place and especially into my eyes, will try again tonight but if anyone has any suggestions i would be grateful so it doesnt turn out to be a total waste of £100.

Debbie

[Barely Awake]

Thanks for all that and your other helpful posts James.

The sleepnetphantom looks an interesting design that would fit my busted nose but sadly unless the side port makes a difference it has little likelihood of working for me as my nostrils tend to collapse and close off inside a normal hard mask. Hence I hoped the sleepweaver might work as it is blowing in the right direction to inflate the nostrils as well as the mask.

Having a badly displaced septum I also can't use nasal pillows, so only the under cushion on the ComfortCurve or Comfortlite work for me at present, but sadly I can't get enough purchase to get a seal with the latter. There are a lot of OSA patients with displaced septums I was told (half someone suggested) so you would think more under cushion designs would be made.

What I would like is a Swift light with an under cushion... I'm sure that would be popular with a lot of OSA folk as the Swift doesn't feel like you have a mask on at all.

[James @ Intus]

BTW has the Sleepweaver been officially trialled in the UK?

Only 3 or 4 masks have been officially trialled full stop, let alone the UK. The SleepWeaver grabbed some interest from CPAP researchers and we expect something to happen this year in that field but it's really like researching something we already know, that patients get on great and love them. So there isn't much point in a way, but it may indeed help convince some doctors. So we're working on it!