US Patent 8225796 Respiratory therapy system including a nasal cannula assembly

A nasal cannula, for supplying a respiratory gas to a patient, comprising: a pair of spaced apart supply lines which each have a head at one end thereof with a discharge opening therein. The opposite end of each supply line is connectable to a respiratory gas source. Each head is sized to be snugly received and retained within one of the nasal cavities of the patient while forming a sufficient leakage passage, between a portion of inwardly facing nasal cavity skin of a patient and a portion of an exterior surface of the head, to facilitate exhausting of any excess respiratory gas supplied to the patient through the leakage passage and also facilitate inhalation of any room air required in excess of the respiratory gas to be supplied to the patient. The invention also relates to a respiratory therapy system incorporating the nasal cannula, a method of treating a patient with sleep disorder by using the nasal cannula, a diagnostic tool for measuring nasal cavity pressure of a patient, and a method of using the diagnostic tool for measuring nasal cavity pressure of a patient.