The most common and non-evasive therapy for sleep apnea is Positive Airway Pressure, or PAP, therapy.

The best way to describe how positive airway pressure works is to use the example of inflating a balloon.

When your upper airway is obstructed by relaxed tissue during an apnea event, the upper part of your throat is like a collapsed balloon. Some balloons are difficult to fill with air. To get the balloon to inflate you have to exert more pressure.

The same idea is used to treat sleep apnea with positive airway pressure. For some patients a low pressure is all it takes to gently open the airway. However for other patients the pressure may have to be much higher to open the airway and eliminate the obstruction.

Positive airway pressure acts like a splint or cushion of air that holds your upper airway open as you sleep allowing you to breathe in and out normally.

A PAP unit is the combination of a small device (that converts room air into pressurized air) and a small mask that fits over your nose and/or mouth. The mask is connected to the PAP unit by a flexible tube through which pressurized, heated and humidified air is delivered to you while you sleep. 

CPAP delivers a steady and gentle flow of pressurized air to you throughout the night.

The constant flow of pressurized air maintains an open airway during sleep preventing airway narrowing or obstruction. CPAP therapy is considered the most common treatment of choice.

Bi-PAP delivers two different pressures. The first pressure is set higher, working like CPAP to prevent narrowing or obstructing of the upper airway while you breathe in. The second pressure is set lower making it easier to breathe out.

Bi-PAP therapy is usually prescribed to patients who have difficulty adjusting to CPAP or have central sleep apnea. There are multiple Bi-PAP units designed to treat more complex cases of sleep apnea by offering additional adjustment options.