CPAP Humidity Issues

This is an excerpt from my forthcoming book, The 7 Day Sleep Apnea Solution: Get the sleep you need and the life you want. Please feel free to make comments and suggestions. If I select and implement your suggestions, I’ll acknowledge you in my book.

Next to the mask, humidification issues can either make or break your CPAP experience. Even 10 years ago, humidification was an option for most patients. Doctors could prescribe either a cool water passover humidifier or a heated humidifier. Passover humidifiers work by passing air from the CPAP machine over a chamber filled to room temperature air. We now know that this setup isn’t strong enough to make any significant difference with humidity settings. These days, heated humidification is standard, with numerous studies showing that using it can significantly increase CPAP usage and comfort levels. It’s also one of the few comfort features that you have control over. 
Passing dry air can cause a lot of nasal problems, including dryness, crusting, nosebleeds, and nasal congestion. If your nose is congested, then you’re more likely to open your mouth. This can worsen mouth leaks, with can lessen CPAP effectiveness. So if your nose gets congested when staring with CPAP, one option is to try increasing your humidity level.
At the other extreme, you can have too much humidification. Depending on what type of climate that you live in, and how much humidify you have in your bedroom, humidity levels from your CPAP machines can vary greatly. Some newer models actually adjust humidify levels based on the room’s temperature and ambient humidity levels. 
One common problem is something called rainout. Since the air is heated and humidified, and if the room air is cold, then the water vapors inside the tube can condense, leading to water accumulating inside the tube. it can be disturbing to have water coming into your nose in the middle of the night. As I mentioned before, this can be solved by either turning down the humidification level, covering the tubing, or adding a heated tubing system.
According to manufacturers, the water tank should be emptied and washed every day. If you look on the online CPAP forums, people have widely varying cleaning schedules. Since everyone will have different patterns of use, everyone will have different cleaning schedules. Emptying the tank every day and washing once weekly is probably a reasonable schedule, but your requirements may vary. Rinsing the tank with some white vinegar in water once a week is also generally recommended to disinfect the tank. 
What type of water should I use for CPAP?
Manufacturers recommend distilled water. In general, recommending distilled water is not for safety reasons, but more for the durability of the water chamber and the machine. Mineral deposits from tap water can build up and potentially damage the machine. If you’re in a pinch, it’s OK to use bottled water, but try to go back to using distilled water as soon as possible.
There are reports of people successfully using boiled water or from reverse osmosis. Regardless, if your water chamber gets covered with grimy material to quickly, then it’s probably time to re-evaluate your choice of water.

 Next: Miscellaneous CPAP topics

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3 thoughts on “CPAP Humidity Issues

  1. Jim Hales DDS and I would like to know why after five years of using a CPAP my legs and arms would start moving. In fact the whole body would shake at times.

    After three years of using a MAD device tried the CPAP and on the second night the shakes reappeared.

  2. Mr. Miller,

    One possible explanation is that your CPAP pressure may not be adequate after 5 years. It can be either too high or too low. Arm and leg movements (periodic limb movements) have been shown to be significantly diminished with CPAP in a laboratory setting. This may not be mainstream thinking yet, but you can think of limb movements being similar to dental grinding or clenching as a protective mechanism to wake up from deep to light sleep when your breathing begins to obstruct.

  3. I found that raising the humidity on my CPAP above 2, caused me to have increased AHI’s can you explain why this would happen? When I raised from 2 to 4 humidity my AHI’s went from very low figures between 2-5, right up to 17.5 AHI! When I reset the humidity back down to 2. I dropped my AHI back to 2.0.