Q. As I mentioned yesterday I have lately some respiratory problems and I am waiting to see a specialist (takes too long).
I cannot walk long time,, cannot climb stairs and very often I have some coughing attack – especially night time.
I am using a CPAC machine to distribute oxygen when I am sleeping.
1. What is the Chalacha to use this kind of machine on Shabbat? It has a small electric motor that is helping to pump air into your body.
2. When I am using it I am getting dry mouth and have to drink a few sip of water on night time. What to do on a fast day?
Maybe you had this questions answered on Frum Toronto.

A. Indeed we addressed the question on 389 and 467, which I quote: “If someone has sleep apnea, and is advised by doctor to use a sleep apnea machine every night, can one use it on Shabbos, which requires pushing an electric button to activate it and turning it off in the morning?
A. Horav Shlomo Miller’s Shlit”a opinion is that when there is a compelling need for operating the apnea machine on Shabbos, as when the user cannot fall asleep without it (even if his life is not presently in danger), it can be used if it is connected to a timer that automatically turns it on. It should also be the type of machine that does not have a sensor that turns it on and off, responding to the breathing and also adjusts accordingly the pressure needed in real time, (APAP or Auto Positive Airway Pressure system) but rather the simpler continuous air stream machine.
A trial should be done before Shabbos to see if the timer set up works properly.”
You use a CPAP, or Continuous Positive Airway Pressure, which is a form of positive airway pressure ventilator, that applies mild air pressure on a continuous basis to keep the airways continuously open in people who are able to breathe spontaneously on their own. From our recent conversation, it is clear that this machine is also controlled by the breathing of the user and it is also continuously monitored remotely by technicians at a central location.
Horav Shlomo Miller Shlit’a suggested to have them add to the machine an optional switch that can override the sensors and monitoring devices for Shabbos use.
If that is not a possibility the Rov further suggested to obtain for Shabbos use, a simple continuous respirator. You should consult with your doctor before doing any changes.
Please get back to us I you were not able to do the above.
As far as alleviating the dry mouth ailment during a fast day, the Rov would recommend using a humidifier, after consulting with the physician and the technicians involved. The Rov also suggested if possible just gargling with water, without actually swallowing. This would not be permitted during Yom Kippur.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a