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Why is My CPAP Trying to Drown Me?

by / Thursday, 19 April 2012 / Published in Cleaning and Comfort, Sleep Apnea and CPAP

It’s funny when Moe spritzes Curley in the face with a seltzer bottle. It’s not so funny when your CPAP machine does the same to you at 2:30 in the morning. Rainout, as it’s commonly known, is the buildup of condensation inside your CPAP tube. This condensation can travel through your mask, into your face and up your nose. At best, it’s a mild annoyance. At worst, it can severely disrupt your sleep, defeating the benefits of your CPAP therapy. So how should it be dealt with?

First off, we need to get an understanding of what’s actually occurring with rainout. Rainout results when water vapor traveling from the humidifier comes in contact with the cooler, inner wall of the tubing. (Picture the outside of a cold can of soda on a humid summer day.) Such vapor condenses, and forms droplets. These droplets can accumulate to such an extent that rolling over in bed can send an army of them rushing toward your face with the force of the Old Faithful (or so it might seem). Many a CPAP user has awakened gasping and reaching for tissues to dry themselves off.

The first way to deal with this is to let gravity work for us. If possible, the CPAP machine should be located lower than our mask when we’re in sleeping position. If this can’t be done, we should at least position our hose so that there’s a substantial hose droop that hangs lower than the rest of our gear. Now, any accumulated water will have to fight the forces of gravity in order to reach our face.

Another way to deal with this is to go without a humidifier. This is probably not a good option. The benefits of humidified air in CPAP therapy are well documented. Not to mention the oral and nasal dryness that can occur when not using a humidifier. Perhaps a compromise can do the trick. Simply turning down the setting might be enough to cut back on the water content of the air passing through the tube, and thus stop the rainout.

Still another approach would be to change the ambient room temperature to more closely match that of the heated water vapor passing through the CPAP tube. If you’re like me, and you’re particular about your sleeping climate, (I don’t enjoy sleeping in tropical rainforest-like conditions), this approach may not be for you.

The most common way of conquering rainout is to insulate your CPAP hose. (Picture a cold can of soda on a humid summer day–only now it’s in a foam cooler) This can be done in a number of ways. First, the low tech approach: For this you need to fashion some kind of sleeve to cover the length of your hose. I’ve heard of everything from sweatshirt sleeves, to athletic socks with the toes cut off, being used for this purpose. (Note: if using athletic socks, please wash first!) For those handy with needle and thread, you can purchase fleece or similar insulating material at your local fabric outlet and create your own hose wrap. Many choose to purchase ready-made hose insulators, as they are inexpensive and readily available on-line, or through other outlets.

For those with serious rainout problems, ones that ordinary hose insulators can’t seem to fix, there’s the Rolls Royce of rainout solutions: The heated CPAP hose. This type of hose has a heating element running through its length that elevates the temperature just enough so as to keep the humidifier water in vapor form. This style of hose replaces your conventional CPAP hose, and either plugs into the wall, or is powered by the CPAP machine itself. While somewhat pricier than the other rainout remedies, many have found that a dry night’s sleep is worth the extra expense.


Getting the hang of CPAP therapy presents enough of a challenge in itself. Do we really need the extra insult of being spit in the face by an ungrateful machine? The answer is no! Fortunately, we have enough resources at our disposal to allow us to finally say no
to rainout.

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