A medical mouthpiece may include a U-shaped first member (110) having a tubular portion, the first member forming at least one lateral interocclusal passageway (116) extending through the first member (110), and a second member received within the tubular portion. A medical breathing apparatus may include a U-shaped first member forming left and right lateral interocclusal passageways (116) extending through the first member (110), a second member (180) attached to the first member (110), and an adapter receivable within a tubular portion of the first member (110), wherein the adapter includes a respiratory orifice configured to deliver respiratory gas to the left and right lateral interocclusal passageways (116). A method for delivering positive pressure and/or a respiratory gas to a patient may include inserting a mouthpiece (100) into a mouth of the patient, and delivering the positive pressure and/or the respiratory gas through the mouthpiece (100) to a space adjacent a posterior oropharynx of the patient.
