What is the PRIMARY function of the EPAP setting in a bi-level device?

The primary function of the EPAP (Expiratory Positive Airway Pressure) setting in a bi-level device is to maintain a patent airway during sleep. EPAP works by providing a baseline level of pressure that keeps the airway open, preventing collapse during expiration. This is crucial in conditions such as obstructive sleep apnea, where the airway may become obstructed, leading to apneas and hypopneas. By providing this positive pressure, EPAP helps to ensure that the airway remains open and allows for normal airflow during sleep.

In addition to maintaining an open airway, EPAP can also indirectly contribute to reducing oxygen desaturation and preventing arousals that often occur in response to airway obstruction. However, its primary mechanism is focused on keeping the airway patent. While enhancing oxygen delivery and reducing CO2 retention are important aspects of overall therapy, they are more closely related to the overall function of the bi-level device and the pressures set, rather than being the primary role of the EPAP setting itself.