what is there to know?


CPAP machines are used to provide continuous positive airway pressure to help treat people with sleep apnea and other types of breathing difficulties. The pressure can be adjusted based on the needs and comfort level of the person being treated. Generally it is the doctor's responsibility to decide what pressure setting is appropriate for the patient. Just like with most other types of treatment, the doctor will fill out a prescription and the pharmacist will take it from there. The CPAP machine manufacturers would prefer to keep things this way (I'm assuming for the sake of liability), but there's nothing stopping a patient from adjusting his or her own CPAP settings. Please review this site for more information on adjusting CPAP settings.


The ramp feature available on most CPAP machines allows a person to start with a low pressure and then gradually have it raised depending on how long it takes the person to fall asleep. Generally it is set to 10 or 15 minutes but it can be as long as 45 minutes or so if that's how long it takes for the patient to fall asleep. The method of adjusting the ramp setting varies by manufacturer and model so the user should consult the manual or his or her doctor with questions.


Pressure for CPAP machines is measured with a device called a manometer. Picture a U-shaped tube filled with water. When air pressure is applied to one end of the tube it causes the water to climb on the other side. CPAP settings can range from about 4cm h20 to about 20cm h20. What this means, for example, is that when the CPAP machine has a setting of 10cm h20, the water is moved up the other side of the tube by 10cm. The higher the number of centimeters, the greater the pressure.