Condensation in CPAP hose and Rain Out

Condensation in the hose during CPAP or BiPAP treatment is an annoying and irritating problem that many sleep therapy patients have experienced.   Water vapor that is in the pressurized air flowing through your CPAP hose to the mask condenses into liquid water and begins to pool.    The condensation in the hose can create annoying gurgling noises as the blowing air from the positive airway pressure (PAP) machine pushes the water up the tube.  When enough water has formed, the pressurized air can actually push the water through the mask and splash you in the face.  This rude splash is known as rain out.

This is most common for patients that are using a heated humidifier with their PAP equipment.   Because continued exposure to the dry and pressurized air of CPAP therapy can result in nasal irritation from dry nasal passages and also cause dry mouth and other discomforts, many patients opt to use heated humidification with their CPAP or BiPAP machines.   Heated humidifiers warm and moisten the air, making the air more comfortable to breath in.  However, the warm moisturized air from heated humidifiers does tend to leave condensation in the CPAP hose.

Warmer air is able to hold more moisture, and the heated air leaving the heated humidifier contains a lot of water vapor.  Cool air is less able to hold moisture and so when the warm moist humidified air cools, the water vapor in the air condenses into liquid water.   As the warm and moist air moves down the CPAP tube towards your mask, it starts to cool and some of the water vapor will condense in the tube.

Typically the temperature drops during the night, and so as you are sleeping with your CPAP machine running with the heated humidifier, more and more condensation begins to form in the tube as the night air becomes colder.  As a result, liquid water begins to accumulate in the tube, causing the gurgling noise that gets worse as more water forms.  When enough water forms, it can get pushed up through your mask and splash you. 

The best way to reduce or eliminate condensation in the tube is to keep the air in the tube from cooling down.  A simple and inexpensive solution is to wrap your CPAP hose with a tube cover.  The tube cover serves to insulate the hose so that the temperature inside the hose remains more constant.

It does not take a very large temperature drop to cause water vapor to condense into liquid water.  Wrapping your CPAP hose with tube cover keeps the air temperature inside the tube from dropping with the ambient room temperature as it gets colder in the night, so that condensation will not occur.  The tube cover can keep the temperature inside the tube more constant, and reducing the condensation.

Tube covers can also serve to make your PAP equipment less clinical looking as they come in different colors and prints.  Tube covers can also serve to protect the tube from becoming punctured or damaged.

Another solution to help reduce or eliminate condensation is to use heated tubing.  Heated tubing operates on the same principle as using a tube cover in that the goal is to keep the air temperature inside the tube warm so that the water vapor in the pressurized air does not condense in the tube.  The Hybernite Rainout Control System is a great stand alone heated tube system that effectively eliminates condensation.

The Hybernite Rainout Control System is a heated tube that you plug into an outlet.  Copper wires along the length of the tube generate heat to keep the temperature inside the tube warm and constant and therefore eliminating condensation within the tube.

Condensation in the tube can be very irritating.  To better comply with your sleep therapy, you can use the aforementioned solutions to eliminate the problem of condensation and rain out so that your PAP treatment is more comfortable you can get the sleep that you need.

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