EPAP is an acronym that stands for "expiratory positive airway pressure." For a person on a ventilator, this would refer to positive airway pressure being provided while they breathe out.
EPAP can also be used to describe a device used to treat sleep apnea called Provent. According to the manufacturer, Provent uses a one-way valve that is placed over the nostrils at nighttime. The valve opens when you inhale, but partially closes during exhalation, creating positive pressure in the airway.
Unlike CPAP, another device for treating sleep apnea, Provent does not use water or an electrical power source. It's also more portable. The manufacturer claims that this is an advantage, and that their studies have shown greater compliance with EPAP than is typically seen in people using CPAP for the treatment of sleep apnea.
While the Provent device may be promising, more studies are needed. Only your doctor can help you decide on the best treatment for your sleep apnea.
Provent Sleep Apnea Therapy. About Provent Therapy. Accessed: June 12, 2010 from http://www.proventtherapy.com/about-provent-therapy.aspx
Rosenthal L, Massie CA, Dolan DC, Loomas B, Kram J, Hart RW. A multicenter, prospective study of a novel nasal EPAP device in the treatment of obstructive sleep apnea: efficacy and 30-day adherence. J Clin Sleep Med. 2009 Dec 15;5(6):532-7.