New S9 humidifier uses way more water than the loaner

[Paul_H]

Hi:

I just got my permanent ResMed S9 Autoset, with the humidifier and climate control hose, after using an apparently identical machine on loan for 6 weeks. I'm a bit perturbed, as - at exactly the same temperature and humidity settings - the new machine uses easily twice the amount of water as the old one. I used to be able to get 2-3 days from the old one without refilling, now I get a day, but have to refill each night, as over half the water has been used overnight. Any ideas about this? I'm reluctant to ask the technician who sold it to me, as I apparently already know more about the machine than he does, so I wouldn't expect much of an answer from him. Is one or the other machine defective? If so, which one? Oddly enough, I don't really notice any great change in the amount of humidity I am receiving, although I am getting a bit of condensation in the mask, which I don't remember seeing before. Not enough to bother me, though.

My settings are: temp - 28C (82F), and humidity - 4.5.

Thanks.

Paul

[Sleepless in Ca]

I have the same machine and find my water lasts 3 nights. Though I wonder if it works at all as often my mouth is so dry it is horrible. This is the main thing that makes using CPAP so miserable.

[Pugsy]

Amount of water consumed is usually related to
1. Ambient room humidity...has that changed?
2. Pressures used...higher pressure needs will use up more water
3. Leaks...higher than normal leaks will use up more water
4...combination of 1 through 3.

[Pugsy]

I have the same machine and find my water lasts 3 nights. Though I wonder if it works at all as often my mouth is so dry it is horrible. This is the main thing that makes using CPAP so miserable.

The usual culprit for dry mouth is mouth breathing/leaking/opening and it doesn't take much mouth breathing to dry out the mouth.
Are you still using a full face mask? If so, you are likely mouth breathing. The humidifier can't always keep up with the drying effects of mouth breathing even at max setting. So while a full face mask will keep the therapy pressure within the close circuit it can't always rehydrate the mouth sufficiently. The humidifier just can't put out enough added moisture for some people's mouths even at max setting.
Of course there are other reasons for dry mouth...meds, etc and they can of course make any mouth breathing dryness..worse.

[Paul_H]

Amount of water consumed is usually related to
1. Ambient room humidity...has that changed?
2. Pressures used...higher pressure needs will use up more water
3. Leaks...higher than normal leaks will use up more water
4...combination of 1 through 3.

Hi Pugsy:

Thanks for the thoughts. I did increase the lower pressure from 6 to 7. However, that minor adjustment seems unlikely to have caused the dramatic increase in water consumption. The humidity and temperature at night fluctuates like normal, but it did so with the loaner machine too, and is always in the 40-50% range for humidity, and temperature has been fairly average for this time of year at night.. Leaks are less now that I've switched to a nose pillow mask.

Still a mystery to me.

Paul