Abstract: An oxygen delivery device for delivering oxygen to a patient. A delivery mode selector is movable between first and second mode positions. A delivery rate selector is movable over a range and includes a first set of scale indicia having a first calibration and a second set of scale indicia having a second calibration being different from the first calibration. A method of operating the device includes selecting a first mode of operation of the device by setting the delivery mode selector to the first position and selecting a delivery rate by operating the delivery rate selector using the first set of scale indicia. The method also includes selecting a second mode of operation of the device by setting the delivery mode selector to the second position and selecting the delivery rate by operating the delivery rate selector using the second set of scale indicia.

Abstract: Passive humidifier for a continuous positive airway pressure (CPAP) device having a plurality of chambers defined by arced baffles. Each opening between the arced baffles is provided with a deflector baffle to prevent direct passage of air.