The Stanford Center for Sleep Sciences and Medicine

Types of Therapies

Continuous Positive Airway Pressure (CPAP)

Continuous Positive Airway Pressure (CPAP) therapy was developed by Colin Sullivan of Sydney Australia in 1981 and delivers a fixed, or stable, pre-determined level of air pressure. Since there is only one pressure, it remains the same during the inhalation and exhalation.

CPAP is typically the first PAP therapy used to treat sleep disordered breathing. Itís simple approach to supporting the airway is effective for many sleep apnea patients. However, it may not successfully treat everyone. If your symptoms arenít eliminated after consistent use of the device, contact your doctor to assess whether your pressure needs to be adjusted or if you would benefit from a different PAP option such as an auto-titrating device or a BiLevel machine.

BiLevel Positive Airway Pressure

BiLevel Positive Airway Pressure (BiLevel) machines have two different pressures; a higher pressure when breathing in and a lower pressure when breathing out. By alternating the inhalation and exhalation pressures, the BiLevel encourages the lungs to operate more efficiently.

Most BiLevel machines work by switching between the two air pressures in response to your breathing. This is known as spontaneous BiLevel. However, patients with more complicated pulmonary disorders (chronic obstructive pulmonary disease, emphysema, etc.) may require the machine to set the respiratory rate through either a backup rate or a timed rate. Most BiLevel machines can deliver up to 30 cm H2O.

BiLevel machines can also be an effective treatment option for Central Sleep Apnea.

Auto-Titrating Devices

An auto titration PAP machine, also called a ďsmartĒ machine, adjusts the air pressure in response to changes in your breathing pattern, allowing the pressure to vary across the night. The auto titrating machines have an algorithm that increases the air pressure when your breathing is compromised and lowers the air pressure after a period of normal respiration.

Auto-titrating machines are ideal for people who need a significantly higher pressure during just a portion of the night, for instance when sleeping on their back or in REM sleep because you donít need to fix the pressure to the highest level needed. Instead, the changing pressure allows you to have the lowest pressure possible throughout the night. Auto-titrating machines also work well to compensate for minor weight changes or use of alcohol or other sedatives. However, the algorithms are not perfect, and factors such as a mask leak can interfere with the machineís feedback loop, which may result in the wrong pressure being delivered.

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