Abstract: A nasal respiratory mask for a high flow oxygen therapy apparatus, comprising: a mask frame; and a mask cushion on the mask frame for contacting and substantially sealing against a face of a patient, the mask frame and mask cushion defining a nasal breathing cavity, wherein the mask frame comprises: a hose attachment portion for attaching a hose for delivering a supply of oxygen enriched air to the patient; and a mask aperture for restricting the flow of gas from the nasal breathing cavity directly to ambient, wherein the mask aperture maintains a positive end-expiratory pressure (PEEP) in the nasal breathing cavity of between 0.2 kPa and 1 kPa during the administering of high flow oxygen therapy to the patient.

Abstract: A nasal respiratory mask for a high flow oxygen therapy apparatus, comprising: a mask frame; and a mask cushion on the mask frame for contacting and substantially sealing against a face of a user, the mask frame and mask cushion defining a nasal breathing cavity, wherein the mask frame comprises: a hose attachment portion for attaching a hose for delivering a supply of oxygen enriched air to the user; and at least one of: i. a passive one-way valve configured to move from a closed position in which air is restricted from flowing through the one-way valve, to an open position in which air can flow from the nasal breathing cavity through the one-way valve to outside the mask, wherein the one-way valve has a valve opening pressure of between 0.2 kPa and 1 kPa, ii.