water chamber

The doctor is changing me from an AutoPap to a BiPap. I am trying to decide between the ResMed AirCurve10 BiPap and the Respironics Dreamstation BiPap. My current autopap is a Respironics System One. The pressure is set at 16-18. It doesn't have heated tubing, but I have an insulated cover for the hose. The humidity is set to a 4 (5 being the highest). Because my mouth is still so dry when I wake up, I would like to go to the highest level, but the water chamber runs out of water after about 5 hours.

I would like to avoid this problem with my new BiPap machine. While researching, I noticed the ResMed AirCurve10's water chamber is 380 cm3 versus the Dreamstation's 325 cm3. Do the water chambers on both of these machines run out of water if set to the highest humidity level after 6-7 hours of use? Is there rain out if set to the highest level or does the heated tubing prevent that problem?

With the BiPap, my pressures will be a little lower than with the C Autopap I now use. Will that make a difference in how much water is used? The BiPap's inhale pressure will be 14, and the exhale 10. I use the Amara View full face mask, and have no mask leaks. I am a mouth breather and have not been able to change that, hence the full face mask. We live in southern NM where the climate is dry most of the year. I would like to get the Dreamstation, but just don't want to run out of water too soon.

Thanks for your help.

Hi baseten. How quickly the water evaporates from the chamber depends on many things. Some examples are humidity level in the room, room temperature, whether heated tubing is being used, and how much you are mouth breathing. Rain out also depends on some of these same things. Heated tubing can help with both rain out and with keeping keeping the humidity level a bit higher at the mask to prevent dry mouth. Whichever machine you choose, you might consider a room humidifier to help with moisture in the air. Best wishes!

Ahhh dry mouth! I think the first thing I would look at would be your leak rate. If your mouth is opening and you breathe through your mouth, the water will go FAST and if you turn the humidity level up to help ease the dry mouth, well, the tank will go down even faster. I can say this because it was a reality in my case. I had dry mouth so bad that I tried every spray, mouthwash and lozenge on the market. Nothing helped totally till I figured out how to keep my jaw from going slack and my mouth slipping to the low edge of my full face mask and my mask leaking. My AHI was still pretty good but the dry mouth was not. Today I can turn off the humidity without having any dry mouth at all. I do get chapped lips if I do so I run it on 3 in a range of 0 to 10.