Disclosed are devices, systems, and methods, including an oxygen delivery device that includes an oxygen delivery module, at least one sensor to detect patient breathing, and a controller configured to control the oxygen delivery module to cause the oxygen delivery module to deliver oxygen to the patient based on data from the at least one sensor such that in response to a determination, based on data from the at least one sensor, that no breathing is detected for a first pre-determined period of time, the controller causes the oxygen delivery module to deliver oxygen to the patient in continuous flow mode, and in response to a determination, based on additional data from the at least one sensor, that breathing is detected for a second period of time, the controller causes the oxygen delivery module to deliver oxygen to the patient in a pulse flow mode.