A patient interface is provided for sealing a delivery
airflow to improve sleep
breathing disorders. The patient interface includes a seal forming structure for forming a pneumatic seal with a patient
airway inlet; a positioning and stabilizing structure for maintaining the seal-forming structure in sealing contact with an area around the
airway inlet of the patient; a
plenum chamber pressurized in use at a pressure higher than
ambient pressure; a connection port for delivering a flow of breathable gas into the patient interface; and a device positioned within the
breathing chamber defined at least in part by the seal-forming structure and the
plenum chamber, where the device divides the
breathing chamber into a posterior chamber and an anterior chamber, and where the device includes a plurality of apertures to allow air to pass through the device and to capture hot and / or moist air by a patient, and exchange at least part of heat and / or
moisture with the air inhaled by the patient.