We disclose a mask for administering a breathable gas to a patient, which comprises a mask body and a gas flow disrupter joined to the mask body for generating a turbulent gas plume rearwardly towards the nose and mouth of the patient. The mask body is configured to position the flow disrupter so as to be spaced from and opposing the patient's nose and mouth region when the mask is worn by the patient. The mask includes a gas inlet for admitting gas from an external source into the mask interior, through the gas flow disrupter. The gas flow disrupter can be configured to generate a turbulent gas plume wherein the velocity of gas exiting the disrupter is approximately the same as the gas velocity entering the mask from the gas inlet.
