Portable Oral Positive Expiratory Pressure-Generating Devices with Variable Expiratory Airflow Resistances

A method of reducing a subject's respiratory rate compared to the subject's normal respiratory rate comprising the subject placing a rigid hollow device in their mouth and breathing through the rigid hollow device for a period of time, the rigid hollow device having at least one air chamber, at least one opening in the portion of the rigid hollow device that is held in the mouth and at least one additional airflow orifice;

• wherein the rigid hollow device is configured to be supported by the mouth of the subject without the need for additional support by hands or another device, and further, wherein the subject has a breathing cycle with an exhalation phase and, when the rigid hollow device is in use, it prolongs the exhalation phase of the subject's breathing cycle.

A method of maintaining an oxygen saturation level for a subject with one or more pulmonary disorders who experiences exertional desaturation comprising the subject placing a rigid hollow device in their mouth and breathing through the rigid hollow device for a period of time, the rigid hollow device having at least one air chamber, at least one opening in the portion of the rigid hollow device that is held in the mouth and at least one additional airflow orifice;

• wherein the rigid hollow device is configured to be supported by the mouth of the subject without the need for additional support by hands or another device, and further, wherein, during exertion, the subject maintains an oxygen saturation level at or above 88% of a resting oxygen saturation level.