A self-administered oxygenation apparatus for increasing pressure within a non-intubated patient's lungs and thereby increasing an amount of oxygen in the non-intubated patient's blood when operated by the patient includes a mouthpiece, a vent member, and a resistance member. The mouthpiece includes an external portion defining a center orifice through which the patient selectively inhales and exhales air. The vent member includes a continuous side wall fixedly coupled to the external portion of the mouthpiece and defining an interior area in fluid communication with the center orifice. The resistance member is positioned between the interior area of the vent member and the mouthpiece, the resistance member having a flexible construction configured to fold inwardly upon inhalation so as to allow ambient air inhaled by the patient to pass thereby without resistance and having a perforated construction configured to decrease the flow of air exhaled by the patient.