Fixed or single pressure CPAP is a mode of therapy that delivers a single pressure regardless of the breathing cycle. For instance, a fixed CPAP machine will deliver 10 cmH2O all night long, no matter if the patient is inhaling or exhaling, contrary to other machine modes that are capable of delivering a two pressures during inhale and exhale or a range of pressures.
Fixed CPAP machines are generally capable of delivering 4-20 cmH2O.
Later generations of machines will include comfort features, such as EPR and FLEX, that make the machine more comfortable to use.
A fixed CPAP machine is used for the treatment of Obstructive Sleep Apnea (OSA).