To understand how a Bi-Level Positive Airway Pressure (BiPAP) machine works, it is necessary to first understand what it is. A BiPAP machine is a device that provides non-invasive ventilation. What makes these machines non-invasive is the fact that they do not require tubing to enter the body to force air into the human body. These machines are used primarily with patients who suffer from sleep apnea. Sleep apnea is a medical condition that causes the patients airway to narrow or become blocked in some way during sleep. This airway restriction causes the patient to stop breathing for a short period of time. This can occur between ten to fifty times an hour, causing significant oxygen deprivation for the patient.

BiPAP machines work by providing positive pressure when a person breathes in and lowering the pressure upon exhalation. The machine works with two pressure settings. The exhalation pressure, or EPAP, and the inhalation pressure, or IPAP, are both preset to allow the right amount of pressure per breath for optimal benefit. Some continuous positive airway pressure (CPAP) machines are also equipped with a breaths per minute (BMP) setting. This will ensure that if the sleeping person begins to hold his or her breath, the machine will take over and increase pressure automatically, forcing the patient to breathe. The air pressure will then immediately decrease, which allows the patient to exhale properly. BiPAP machines will vary the pressure as the person's pressure needs change throughout their sleeping patterns. This allows the patient to receive a more beneficial sleeping period.

Another benefit to obtaining a BiPAP machine is its size and convenience. BiPAP machines are small enough to fit on the patient's nightstand and quiet enough to run throughout the night without disturbing the other members of the household. These machines also have the option of attaching a heated, or non-heated, humidifier. These humidifiers add moisture to the air that is coming out of the device so as not to dry out the patient's mucous membranes and thereby decreasing the possibility of discomfort during the sleeping period. There are also choices of the type of mask that can be used with the machine. Patients can choose from a nasal pillow mask or a full face mask. Patients can choose the one that they find to be the most comfortable and effective. Nasal pillow masks are usually found to be more light weight and comfortable than full face masks. However, full face masks cover both the nose and mouth for optimal performance.