CPAP Pressure (or CPAP air pressure) is measured in centimeters of water (cmH2O). Standard CPAP machines usually operate within a range of between 4 and 20 cmH2O of pressure. For patients needing higher pressures, some BiLevel (BPAP) machines can be set to a high pressure of up to 35 cmH2O.
How Pressure is Determined
Proper CPAP pressure is usually determined by a titration during a sleep study at a sleep lab. Automatic CPAP machines are capable of adjusting CPAP pressure to a patient's ongoing needs during sleep.
Adjusting CPAP Pressure
Modern CPAP machines have built-in menu systems (in the Clinician Setup Menu) to adjust pressures to the desired levels. Older CPAPs may not have this capability and might need to be adjusted using a manometer. Patients wishing to make small, incremental adjustments to their own CPAP machine should do so only after following the advice on our CPAP Adjustment page.