EPR (Expiratory Pressure Relief)

Expiratory Pressure Relief (EPR) is a ResMed comfort feature that reduces the air pressure during exhalation by 1, 2, or 3 cmH2O below the therapeutic pressure. This makes breathing out against positive pressure feel more natural, as the resistance during expiration is reduced.

EPR settings can affect flow limitation analysis because higher EPR creates a larger pressure drop during the transition from expiration to inspiration. This momentary pressure reduction can sometimes allow the airway to narrow briefly at the start of each breath, potentially contributing to flow limitation patterns in the waveform.

AirwayLab reads the EPR setting from the STR.edf file and reports it alongside other therapy settings. If flow limitation metrics are elevated, one potential approach is to reduce EPR (trading comfort for less inspiratory pressure drop). However, EPR changes should be discussed with your clinician, as reducing EPR may affect therapy adherence if it makes the machine less comfortable to use.