What is EPAP? - Expiratory Positive Airway Pressure

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Why is Positive Pressure Used In Breathing Devices?

If you are live in the United States and are between the ages of 30 and 70 years old, you may be one of the 26 out of 100 people that have sleep apnea. Rates of sleep associated breathing disorders have been on the rise since 2000 as obesity becomes a larger issue. Sleep apnea occurs when your airway collapses; restricting breathing.

If you do not have any lung disorders, you can breath in and out without any obstruction.

However, if you gain weight, it is possible that as you breath out, your upper airway will collapse. This can make it so that the airway does not automatically open back up when you breath and you have an episode of apnea (a temporary cessation of breathing). There are several devices that use positive pressure (pressure going towards the lungs) to assist with breathing. Examples include: CPAP, BiPAP, and EPAP

You should know that while we will discuss a treatment for obstructive sleep apnea, the best thing that you can do to treat your sleep apnea is to lose weight (unless your sleep apnea is not related to obesity).

Consequences of Sleep Apnea

  • daytime sleepiness & fatigue
  • impaired cognitive function
  • metabolic dysfunction - your body doesn't breakdown or absorb nutrients normally
  • heart disease
  • death

Expiratory Positive Airway Pressure

EPAP is an acronym that stands for "expiratory positive airway pressure." This mode of breathing support only applies positive pressure when you are exhaling.

This is thought to work due to a belief that airway collapse and resulting sleep apnea is most at likely to occur when you are breathing out.

One device that utilizes EPAP to treat sleep apnea is called Provent. This technology is known as nasal EPAP. 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 forcing your exhaled breath out through small holes, creating positive pressure in the airway. 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.

Differences Between EPAP, IPAP, CPAP & BiPAP

CPAP, continuous positive airway pressure, is one the most common methods for treating sleep apnea. With CPAP, positive pressure is applied by a machine constantly throughout both inspiration and expiration phases. BiPAP (bilevel positive pressure) applies positive pressure during both phases as well, but not as a continuous pressure. EPAP is different from the previous two modes of breathing support because it does not deliver positive pressure during the inspiratory phase of breathing. It only delivers positive pressure when you are exhaling.

IPAP, inspiratory positive pressure, refers only to positive pressure when you breath in. Ventilators (life support machine for breathing) and BiPAP use both IPAP and EPAP.


American Academy of Sleep Medicine. (2014). Rising prevalence of sleep apnea in U.S. threatens public health. Accessed on 2/28/2016 from http://www.aasmnet.org/articles.aspx?id=5043

Provent Sleep Apnea Therapy. About Provent Therapy. Accessed: June 12, 2010 from http://www.proventtherapy.com/

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.

Yaremchuk, K.L. & Wardrop, P.A. (2010). Sleep Medicine. Accessed on 2/28/2016 from http://www.ebrary.com (Subscription Required)

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