CPAP filters are filters which are used to clean the air which moves through a continuous positive airway pressure (CPAP) machine, ensuring that people inhale clean air while using the machine. Such filters are important for the function of a CPAP machines, and most machines require filter changes every 30 to 60 days, depending on the model. Detailed information about the filter models a particular machine accepts are found in the user's manual and sometimes inside the filter compartment, along with information about how often filters should be changed.
There are two types of CPAP filters. Some are reusable, in which case they need to be periodically removed, cleaned, and allowed to dry before being replaced. Reusable filters are made from materials which can withstand repeated washing and reuse, although eventually they can clog, requiring replacement. Disposable filters are designed to be discarded and replaced with a fresh filter once their term of use is up.
CPAP filters usually remove bacteria, pollen, and allergens such as pet dander and dust. The filter keeps bacteria out of the machine, ensuring that it will not colonized by harmful bacteria which could cause an infection if inhaled in large volumes. The filter also helps the patient breathe easier while on the CPAP machine, and it avoids the triggering of allergies which can occur when unfiltered air is inhaled through a CPAP machine.
Filter replacement guidelines are just guidelines, not rules set in stone. A user who sleeps with a CPAP machine in a dusty area, a house with animals, or in a region with high pollen counts may need to change the filter more often than recommended. Signs that the filter needs to be changed include decreases in air flow from the CPAP machine, or visible dirt and clogging on the filter itself. It's usually very easy to examine the filter to determine whether or not it needs to be replaced. If a patient does develop an infection or allergies while using a CPAP machine, it may be necessary to send the machine out for maintenance, during which technicians can check for signs of bacterial colonization inside the machine.
Some companies sell additional CPAP filters which attach to the CPAP headgear. Care should be taken when using these products, as they could lower the air pressure and make the machine less effective. As a general rule, people should try to stick to using products like CPAP filters which are authorized for use with their CPAP machines, and if they aren't sure about whether an attachment or filter would be appropriate, they should call the manufacturer for information.