Rainout is when water builds up inside of CPAP tubing. The water sometimes makes a popping or gurgling noise in the tubing and well and build up inside a CPAP Mask. This is very annoying and can wake up a patient from a sound sleep.
Rainout usually occurs when the temperature in the sleeping area is very cool and the humidifier is turned up to high. If patients experience rainout, turning down the humidifier setting may help. Thoroughly drying the tubing each morning will help as well. A hose cover can help to reduce rainout. A hose cover will act as a sleeping bag for the hose. This keeps the warm air insulated. Patients will still be able to receive humidity, but without water build-up. Keeping the hose under the covers may also help. The blanket as well as body heat will prevent rainout from occurring. Most newer humidifiers have a built in sensor that checks the room temperature and the amount of moisture that is being put out by the machine. It will not allow the machine to heat to the point of rain out. Some manufacturers offer climate-controlled hoses which has heated coils throughout the hose. The heated coil keeps the air warm and a consistent temperature so the patient consistently receives the same amount of humidity.