Therapies that mechanically open the upper airway Continuous positive airway pressure (CPAP) therapy CPAP therapy is the most common treatment for OSA. CPAP therapy involves increasing the positive air pressure in the upper airway to prevent the airway from collapsing from negative pressure created when breathing in during sleep. The CPAP machine consists of the motor, hose and mask. The CPAP motor pressurizes and in some cases adds moisture to the air. The pressurized air is then sent through the hose to the mask. Prior to using the CPAP machine, users undergo a titration study to determine the ideal air pressure for sleep. During the study, the user is fitted for a mask. While the user is sleeping, the clinicians slowly increase the pressure of the air released into the mask until the patient no longer wakes up while sleeping. There are three types of masks: nasal pillows, nasal masks and full face masks. Effects are experienced almost immediately. Treatment often reduces snoring and breathing obstructions, improves sleep quality, reduces risk for cardiovascular diseases, lowers blood pressure, increases alertness during the day and reduces daytime drowsiness. One disadvantage of CPAP is that while it initially gradually increases to the optimal pressure level at the beginning of sleep, it stays at that optimal pressure setting, regardless of how the individual’s pressure changes with changes in sleep position, body size or sleep state.