Treshold PEP is used to airway clearance, bronchial hygiene, or as an alternative to chest physical therapy.  Treshold PEP incorporates a flow independent one-way valve to ensure consistent resistance with adjustable specific pressure settings (in cm H2O) which are set by the healthcare professional.

When patients exhale through Treshold PEP, the resistive load creates positive pressure that helps open the airways and allows mucus to be expelled during "huff" coughing (forced expiratory technique.)