A respiration sensor fluid delivery device is provided. The device includes first and second nasal exhalation flow passages that extend through the device, wherein the first and second nasal exhalation flow passages can be aligned in parallel to one another with respect to a nasal respiratory flow direction. A housing of the respiration sensor fluid delivery device fluidly couples with one of a nasal cannula assembly and a respiratory mask assembly. The device provides for respiration monitoring of a subject via a sensor and fluid delivery, such as oxygen, to the subject. Methods of using a respiration sensor fluid delivery device and fluid delivery devices are also provided.