Abstract: A multiple lumen nasal cannula that can be used to delivery two separate supplies of gases to a patient. The multiple lumen nasal cannula includes a first lumen for delivering a first gas and a second lumen for delivering a second gas. The first lumen includes support structure that reduces the tendency of the cannula to kink and lock the delivery of gas to a patient. The cannula assembly includes a mixing chamber positioned near the patient such that the two supplies of gas are not mixed until a location approximate to delivery to the patient. The nasal cannula assembly includes a connecting device that allows the two separate supplies of gas to be correctly delivered to the two different lumens of the nasal cannula.