Posted by BostonBoy on October 19, 2001 at 13:53:03:

In Reply to: Re: Question for Breeze users posted by Jim in Dallas on October 19, 2001 at 10:10:28:

Jim - I'm still having trouble connecting the dots.
But first of all, what make/model of humidifier are you using? Is it rated about 80W power consumption?
Secondly, I suggest that you hose-up and sit on the bed watching what happens over 20-30 mins. while the humidifier setting is at max., if there is a lamp or LED that shows when the heater flicks on and off. You'll quickly see whether the device is working hard to keep up with your needs, or whether it seems to have plenty of spare capacity (in the form of available 'on' time). I'm asking you to do this to make sure that you are generating enough water vapor for your needs, before losing some of it to the condensation that is occurring at the pillows shell (manifold).

Back to connecting the dots:
I think I'm close enough to right when I guess that your humidifier is raising the liquid water temperature to about 110-120degF when it is working flat out.

For argument's sake, presume that your hoses are at about 70degF, because they are insulated. That then is the temperature that governs how much water vapor can be carried at 100%RH to your nasal pillows.

At the end of the hoses you have a small amount of plastic in the shell. It's polycarbonate, it's thin, and it has a surface area of maybe 8-10 sq. inches, a small fraction of the surface areas for the two hoses. The shell is being somewhat warmed by your exhaled breath, let's say at 90degF.

See where I'm going? It's not clear to me that you are losing access to a significant amount of water vapor just because the shell is not insulated! In fact I doubt that much of the air you inhale has actually had enough contact time with the material of the shell to make much difference. Some difference - yes. Enough difference - no.

Do you drink a lot of liquids during the day, by comparison with other people? Are you a very large person? Do you know from your trombone playing that you seem to have much larger lung capacity than other brass players? Those things could make a difference, but I just don't know enough to know whether they could make sufficient difference.

Looking at the whole picture, I'm leaning hard toward thinking that you may be a big saliva producer, that saliva drains back to your throat when you are sleeping, and that a lot of the condensate in the shell comes from that, rather than from loss of water vapor by chilling before it is inhaled. The condensation in the shell does not of itself conclusively prove that you are being under-supplied with humidity.

You could cut up some of the neoprene strap material that is used to hold on nasal masks, and stick it to the outside of the shell, but I'll be astonished if it makes a difference to your nose/throat comfort while sleeping. It might reduce the condensation enough to reduce the already small amount of condensate that can trickle around the edge of the nasal pillows, thereby reducing the slight chilling effect on your lip or cheek when that occurs. But that's an improvement in skin comfort, not in nose/throat comfort.

I'm not sure that I've helped much. I guess that what I'm really saying is that I'd look to the primary source (the humidifier) rather than to the sources of small vapor losses. But warming the air before it enters the humidifier's chamber will likely be ineffective: I think that the plate heater will shut down earlier and longer, and that you will not be able to cheat it into increasing the output significantly. After all, the device is already designed to humidify very much more air than the quantity you actually breathe: it's running all of the time, not just while you are inhaling. And it's designed to fail safe, such that it cannot cause a fire when the chamber runs dry, or burn you if you casually touch the plate.

I'll be verey interested to learn the rest of your findings as you experiment. Good luck!

Follow Ups:

• Re: Question for Breeze users Jim in Dallas 22:06 10/19/01 (1)
  • Re: Question for Breeze users Jim in Dallas 06:50 10/20/01 (0)
• Re: Question for Breeze users BostonBoy 15:30 10/19/01 (0)

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