What is the Difference Between CPAP & APAP?

In order to obtain a CPAP or APAP machine, you first need to confirm your diagnosis of OSA by conducting a sleep study.

CPAP machines provide one constant stream of air at a set fixed pressure. APAP machines automatically adjust the air pressure when an apnoea is detected.

Automatic positive airway pressure (APAP) machines function by adjusting the pressure of the air provided. APAP machines detect the pressure needed in order to prevent an apnoea from occurring. APAP machines will increase the pressure, when an apnoea is present. When an apnoea passes, the APAP machine will decrease the pressure accordingly. APAP ensures maximum comfort, while still keeping your airways open to allow you to breathe easily throughout the night.

Continuous positive airway pressure machines function slightly different to APAP machines. CPAP machines provide one constant stream of the fixed, prescribed pressure. CPAP machines will be set to a fixed pressure, prescribed from your sleep study examination. Fixed pressures are set to the maximum level required in order to keep your airways open.

Automatic positive airway pressure is usually the most common choice of therapy. Find out why below!

APAP is usually the most common form of therapy to treat sleep apnoea as it has many advantages over all other treatment options. APAP machines have the ability of adjusting the airway pressure at any time during the night, through intelligent sensors. Apnoeas detected will automatically increase a raise in pressure. As an apnoea passes, the pressure will lower back down again. Essentially, you are only given what you need at any given time.

CPAP machines are set to a prescribed pressure, from the results conducted in an overnight sleep study unit. The disadvantage of CPAP therapy is that over a period of time, your body will adapt. CPAP machines might not be as accurate as APAP. Losing or gaining weight, suffering from seasonal allergies, a cold or a respiratory infection, might affect the pressure you need. Fixed pressure settings might need to be changed over  a period of time to ensure they are accurate to the pressure required.

Most commonly, APAP machines are the preferable option because they only need a documentation confirming OSA, rather than a specialist fixed pressure setting given in a sleep unit.