The pressure setting for a continuous positive airway pressure, or CPAP machine, varies from patient to patient depending on a physician's recommendations. CPAP is the most frequently used form of therapy for sleep apnea, notes WebMD.
A patient diagnosed with sleep apnea typically undergoes a sleep study prior to using a CPAP machine. The study evaluates the correct level of pressure to keep the airway open and enable normal breathing during sleep. A licensed medical practitioner then issues a prescription for the pressure setting that provides optimal benefit for the patient.
On the occasions that patients need to change the setting on their CPAP machine, such as when relocating to a place of higher altitude, patients can contact sleep disorder facilities and sleep laboratories to adjust the pressure setting, according to the CPAP website. A doctor's prescription is also required to alter the preset in a CPAP machine.