Sleepweaver masks

[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!

[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?

[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.

[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.

[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.

[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

[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.

[symmit]

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

To stop the bridge leaking move the mask as low as you can on your face, and lift it away and back to reseal. It is a very different feeling but if you're machine isn't blowing hard to keep the pressure up then the seal may be good enough.

[Pedallass]

I have been using the sleepweaver for a while now. Like all the other masks I tried it took a bit of adjusting but has been well worth it because I am not left with agonizing nose bridge or sore nostrils (both of these lasted for months after very short use- ) . I have found that the level of the CPAP machine really matters because of the issue of the downward angle of the hose. So I have found a stool that is just the right height and have it beside the bed. Nothing else works- higher or lower- it has to be equal height and right beside the bed. Makes a huge difference as every time the hose falls down it pulls the mask and causes those leaks. As many others have said - dont have the straps too tight. Loosening them can have a surprising effect even when it all feels too loose. And keep pulling up and away from the nose in a kind of pinching movement and re sealing can work. Lastly when I think I am all ready, I flatten it all out slightly and that seems to work. There is a deathly hush when the seal is working that is a great pleasure! (how we get our kicks eh?) Having said all that I have nights when I seem to wake a lot with it. I give myself one night off a week- doesn't seem to make much difference over all...and i need the break! I would say keep persevering for a while longer. Good luck.

[James @ Intus]

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.

Any chance you can take a picture and post it?

[James @ Intus]

Great technical discussion on the effects of longer hoses.

Indeed, often the drop in effective pressure isn't a big deal, especially with APAPs. Some machines have a 10ft hose setting, like the SleepCube. Other machines like the Sandman have an auto-calibrate function. Indeed yet others have an additional pressure line though they seem to be going out of fashion. Not sure how you would extend the pressure line to 8 or 10ft!

@ Debbie - 10 is a very workable pressure so it *should* be OK. Do you sleep on your back or side? Or do you get those leaks when you lie on your back or side at the start of the night?

As a test, you could perhaps stick a band-aid over the cloth and bridge of your nose to at least prove the concept and see if you get a good seal if you were indeed holding down the fabric at the bridge. I appreciate that's not a long-term solution one should have to adopt but it may help answer a few things in your specific situation.

Thanks Pedallass for the additional tips and tricks, that type of feedback is of great help.

[symmit]

Not sure how you would extend the pressure line to 8 or 10ft!

I managed to find a German web based company that sells them with the pressure line in 6, 8 and 10 ft for a much better price than in the UK - also got a shedload of filters from there.

[Barely Awake]

I have been using the sleepweaver for a while now. Like all the other masks I tried it took a bit of adjusting but has been well worth it because I am not left with agonizing nose bridge or sore nostrils (both of these lasted for months after very short use- ) . I have found that the level of the CPAP machine really matters because of the issue of the downward angle of the hose. So I have found a stool that is just the right height and have it beside the bed. Nothing else works- higher or lower- it has to be equal height and right beside the bed. Makes a huge difference as every time the hose falls down it pulls the mask and causes those leaks. As many others have said - dont have the straps too tight. Loosening them can have a surprising effect even when it all feels too loose. And keep pulling up and away from the nose in a kind of pinching movement and re sealing can work. Lastly when I think I am all ready, I flatten it all out slightly and that seems to work. There is a deathly hush when the seal is working that is a great pleasure! (how we get our kicks eh?) Having said all that I have nights when I seem to wake a lot with it. I give myself one night off a week- doesn't seem to make much difference over all...and i need the break! I would say keep persevering for a while longer. Good luck.

Lightweight hose and velcro hose clip would sort the angle/drag of the hose surely?

[Barely Awake]

Any chance you can take a picture and post it?

Have mailed you the images James, there are no markings on it as far as I can see to indicate the maker. My mistake - it does have 360 degree swivels on both ends not on one as previously stated.

[symmit]

Lightweight hose and velcro hose clip would sort the angle/drag of the hose surely?

I'd thought that, but the exit is angled down on an inflated sleepweaver so the bend radius would be huge to get it to go upwards.

As the mask is such a big comfort and compliance thing then I'd say rearrange the room and machine to make it work - the long tube is about the best suggestion I have at the moment (when mine arrives I'll report back)