If you’re a CPAP user, have you ever found yourself waking up with water on your face?Or maybe you’ve been startled awake by a loud gurgling noise – if so, no need to worry!This is a common problem known as rainout, with a couple simple solutions!

What is rainout?
Most CPAP users have a humidifier attached to their CPAP machine, creating moisture that allows the air to be humid and prevent dry mouth. If the room temperature is colder than the temperature of the humid air inside the CPAP tubing, water condensation will accumulate inside the tubing. This causes rainout – water droplets dripping onto the user throughout the night.
What are the consequences of rainout?
Besides the discomfort of water dripping on you through your mask during the night, rainout can also have other consequences:
• Noise: Excess moisture in your CPAP tube can lead to some unique noises during the night. These include gurgling, or a banging or knocking as water droplets disrupt the CPAP air flow.
• Bacteria growth on CPAP supplies: CPAP supplies must properly dry out after each use to prevent bacteria buildup. If there is excess moisture in your tubing, this could affect your equipment’s cleanliness as the excess moisture is a breeding ground for different bacteria, molds, and germs!
• Replacing equipment more frequently: Excess moisture that remains in your supplies throughout the day can contribute to the breakdown of the material your CPAP supplies are made of. This can even contribute to tony holes in your tubing which may be difficult to notice.
What can you do to combat rainout?
1. Check out your humidification settings.
Typically, rainout is caused by the air in your bedroom being cooler than the temperature of the humid air inside the tubing. The ResMed AirSense 10 series helps to combat rainout with their Climate Control options:
• Automated Climate Control: This feature automatically adjusts the humidity level of your water chamber, as well as the temperate of your heated hose according to your environment.
• Heated Tubing: The ClimateLine Air heated tube virtually eliminates rainout and delivers ideal temperature and humidity levels to your mask. The tube temperature can be set to anywhere between 60 and 86°F (16 and 30°C) and remain constant despite temperature shift in your room.
• Tube Drier: Once you finish CPAP therapy for the night and your device is turned off, you will see a snowflake symbol flashing at the top of your screen – this indicates the device is in cooldown mode, which helps dry out any moisture left in your tubing.
The Philips Respironics DreamStation and Fisher & Paykel SleepStyle Auto devices also allow for heated tubing, and various settings which can help control rainout.
2. Upgrade to a heated tube.
Heated tubing is an effective way to prevent rainout. If you already have a heated hose and are still experiencing rainout, you may need to manually adjust your settings – try increasing the tube temperature. Increasing the temperature of your tubing will help prevent water droplets from forming, essentially preventing rainout.
3. Use tube cover to protect your tube.
If a heated hose isn’t an option, don’t panic! There’s an alternative that is also effective: a tube cover.
Adding a tube cover helps ensure there is a barrier between any cool air in your room and the warm humid air in your tubing.
Instead of the cool air in your room causing the water vapour to condense, the tube cover will provide a layer of protection and insulation which will ensure the humid air in your tubing does not turn into water droplets!

4. Don’t Forget to Clean Your CPAP!
Although the most noticeable problem with water buildup is the noise and discomfort it causes during CPAP usage, there is a second, less obvious problem that can occur with ongoing rainout. Moisture buildup can lead to bacteria growth in your CPAP hose and supplies!
Regular cleaning and ensuring your equipment is fully dried in between usages can help prevent any bacteria buildup. Currently there are sanitizers available to ensure your CPAP device and equipment are being effectively cleaned, providing peace of mind for CPAP users!
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